Patent Publication Number: US-6661743-B1

Title: Electronic device with display section

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an electronic device having a partially shieldable display section. 
     2. Description of the Related Art 
     Recently, the wearing or display of electronic devices, such as timepieces, as items of fashion has become very common, especially among the younger generation. To be successful, portable electronic devices must have a fashionable appearance and be obviously distinctive from other available products. That is, portable electronic devices are required to be unique. 
     With the above as a background, demand has grown for devices incorporating the ability to display or shield display sections using a shutter function upon demand to achieve versatile display choices for a varied intents and purposes. For example, the user of such a device may wish to use certain display elements only in a specific occasion, may wish to keep the display hidden most of the time to allow others to view certain elements only when the user wishes, may wish to use the display while keeping certain information confidential, or may wish to use the display in a variety of manners. 
     While it may be possible to realize the desired features through mechanical means, employment of mechanical shutters in a portable electronic device would lead to many disadvantages, such as a complicated structure, larger size, and significantly increased cost. Because of these disadvantages, the use of mechanical shutters has been avoided. 
     Therefore, the present invention has been conceived to overcome the above problems and aims to provide an inexpensive electronic device of a simple structure having a display section equipped with a unique shutter function. 
     SUMMARY OF THE INVENTION 
     In order to achieve the above object, according to the present invention, in an electronic device having a display section capable of displaying time, information, and so on, a display section having a plurality of display arrays including at least time display is provided with a light modulating section having a reflection type polarizer at above or below thereof for varying an optical axis of a transmitting light, so that at least a part of the display section can be shielded. 
     With the above, any display which may be unnecessary and/or may impair easy recognition of the displayed information is shielded for refinement of a display section of an electric device into a more easily viewed display section. Further, use of a reflection type polarizer attains neat appearance as a metal-like shielding. That is, with employment of a reflection type polarizer above or below the light modulating section, a part of the display section can be shielded. When a reflection type polarizer is used for one side of the polarizer, a shielded display section presents a mirror-like appearance, which can help maintain an agreeable state. 
     When the display section has both a hand display section and a digital display section, at least one of or a part of the display sections can be shielded by the light modulating section. 
     When the display section is a digital display section comprising a plurality of display arrays or a plurality of laminated display sections, at least one array or layer of the display sections can be shielded by the light modulating section. when one of the plurality of display arrays is for time display while the rest is for display of a time period (such as a chronological time), general information (such as a telephone number), or confidential information, either of the information display sections can be shielded. 
     When the display section includes display characters, such as numbers, letters, symbols, or the like, at least one of the display characters can be shielded by the light modulating section. 
     The display section can be partly shielded when a reflection type polarizer is arranged for either above or below the light modulating section. With a reflection type polarizer used for either above or below the light modulating section, the shielded display section presents mirror-like appearance so that a good-looking state can be maintained. 
     As described above, according to the present invention, there can be provided a unique and versatile display for an electronic device. The shutter mechanism has a simple and unique structure for low cost, which contributes to the ability to offer a wider variation of commodities. 
     In addition, there may be provided an electronic device having a display section, in the form of an LCD electronic watch having an information preparation means for preparing time information or the like, an LCD device for displaying the time information or the like, and a driving means for driving the LCD device. In such a device, an external switch for switching driving or not driving of display of the LCD device by the driving means is provided, and the LCD device may have at least one reflection type polarizer so that, of the segments of the LCD device, either a segment being driven by the driving means or a segment not being driven by the driving means presents a metal-like appearance. 
     Alternatively, a part of the liquid crystal display section, where the segment is not disposed, may present metal-like appearance. 
     In a further alternative, a part of the liquid crystal display section, where the segment is not disposed, may be transmissive. 
     Also, a control circuit may be provided for controlling a driving circuit, based on operation of an external switch, such that the LCD device displays the time information of the like. 
     The control circuit may control the driving circuit such that segments of the liquid crystal display section are sequentially driven, beginning with a segment at an endmost segment of the LCD device. 
     The segments of the LCD device may be divided into upper and lower groups so that the control circuits periodically controls the divided segments sequentially. 
     A frequency from the driving circuit for driving the segments may be gradually changed until the upper and lower segments are both driven before all segments are turned off. 
     As described above, according to the present invention, versatility can be enhanced for a display method for liquid crystal display of information such as a time. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The above and other objects, features, and advantages of the present invention will become further apparent from the following description of the preferred embodiment taken in conjunction with the accompanying drawings wherein: 
     FIG. 1 is a plan view showing a wristwatch according to a first preferred embodiment of the present invention in which FIG.  1 ( a ) shows a digital display section in a shielded state and FIG.  1 ( b ) shows an analogue display in a shielded state; 
     FIG. 2 is a cross sectional view showing major elements of the wristwatch shown in FIG. 1; 
     FIG. 3 is a schematic system diagram for the display shown in FIG. 1; 
     FIG. 4 is a plan view showing a wristwatch according to a second preferred embodiment of the present invention, in which FIG.  4 ( a ) shows a chronological display section and chronological split display section both in a shielded state, FIG.  4 ( b ) shows the chronological split display section in a shielded state, and FIG.  4 ( c ) shows the chronological display section and the chronological split display section both in a fully displayed state; 
     FIG. 5 is a cross sectional view showing major elements of the wristwatch shown in FIG. 4; 
     FIG. 6 is a schematic system diagram for the display shown in FIG. 4; 
     FIG. 7 is a plan view showing a wristwatch according to a third preferred embodiment of the present invention, in which FIG.  7 ( a ) shows a search display and confidential information display both in a shielded state, FIG.  7 ( b ) shows the confidential information display in a shielded state, and FIG.  7 ( c ) shows the search display and the confidential information display both in a fully displayed state; 
     FIG. 8 is a schematic system diagram for the display shown in FIG. 7; 
     FIG. 9 is a plan view showing a wristwatch according to a fourth preferred embodiment of the present invention in which FIG.  9 ( a ) shows display of time, FIG.  9 ( b ) shows a number panel, and FIG.  9 ( c ) shows windows on a light modulating section; 
     FIG. 10 is a schematic system diagram for the display shown in FIG. 9; 
     FIG. 11 is a plan view showing a wristwatch according to a fifth preferred embodiment of the present invention in which FIG.  11 ( a ) shows the wristwatch not with a chronological function not in use and FIG.  11 ( b ) shows the wristwatch with a chronological function in use; 
     FIG. 12 is an exploded perspective view showing an LCD device usable in a preferred embodiment of the present invention; 
     FIG. 13 is a circuitry block diagram showing an LCD electronic watch according to the sixth, seventh, and eighth preferred embodiments of the present invention; 
     FIG. 14 is a plan view showing an LCD according to the sixth preferred embodiment of the present invention; 
     FIG. 15 is a plan view for explaining a display state of an LCD according to the sixth preferred embodiment of the present invention; 
     FIG. 16 is a plan view for explaining a display state of an LCD according to the seventh preferred embodiment of the present invention; 
     FIG. 17 is a circuitry block diagram according to the eighth preferred embodiment of the present invention; and 
     FIG. 18 is a time chart relating to drive signals S 71 , S 72  to be output from a control circuit  307  to a driving circuit  304  of FIG.  17 . 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     In the following, preferred embodiments of the present invention will be described in detail while referring to the accompanying drawings using an example device in the form of a wristwatch. FIG. 1 is a plan view showing a wristwatch according to a first preferred embodiment of the present invention. FIG. 2 is a cross sectional view showing major elements of the wristwatch of FIG.  1 . FIG. 3 is a schematic system diagram for the displaying shown in FIG.  1 . Initially, display configuration of the wristwatch will be described with reference to FIG.  1 . 
     A wristwatch  1  comprises a display section  2  and an operation button  3  for display switching. The display section  2  has an analog display section  4  and a digital display section  5 , which jointly operate to indicate a time, exemplified in the figure by nine minutes after ten o&#39;clock. 
     The wristwatch  1  is equipped with both digital and analog display sections. However, the user may chose to have only one display visible while shielding the other because the combination of displays may actually make time recognition confusing, or simply because the user prefer either the analog or the digital display. For example, the analog display section  4  alone may be displayed, while the digital display section  5  is shielded with a shutter function (described later), as shown in FIG.  1 ( a ). Alternatively, a user preferring digital display may have the digital display section  5  alone to be displayed, while shielding the analog display section  4 , as shown in FIG.  1 ( b ). 
     FIG. 2 is a cross sectional view of the wristwatch  1  of FIG. 1, including the shutter function. A frame  6  of the watch holds a glass sheet  6   a  and a rear cap  6   b . Hands of the analog display section  4  are driven by a movement  7  and a circuit substrate  8 . The digital display section  5 , comprising liquid crystal cells, is driven for display by a signal supplied via a conductive rubber  9  from the circuit substrate  8 . 
     A light modulating section  10  has a function for varying an optical axis of the light having entered from the glass  6   a  side, and a structure comprising a cell  11 , an upper polarizer  12 , and a lower polarizer  13 , as shown in FIG.  1 . The cell  11  comprises liquid crystal with a pattern  11   a  for shielding the analog display section  4  and a pattern  11   b  for shielding the digital display section  5 . 
     At least one of the upper and lower polarizers  12 ,  13  comprises a reflection type polarizer. In this embodiment, the lower polarizer  13  is a reflection type polarizer, though the upper polarizer  13  or both of the upper and lower polarizers  12  and  13  may be a reflection type polarizer. The cell  11  receives a signal from the circuitry substrate  8  through the conductive rubber  14 . The principle and structure of the light modulating section  10  will be described later in detail referring to FIG.  12 . 
     FIG. 3 is a block diagram showing major elements of a circuitry structure. A reference signal generation means  15  comprises a time reference source  15   a  and a dividing circuit  15   b . An information generation means  16  comprises a one-second pulse generation circuit  116   a , driven in response to a signal from the dividing circuit  15   b , and a time counter  16   b . The drawing also shows an analog display driving means  17 , a digital display driving means  18 , and previously described analog display section  4  and digital display section  5 . 
     A display switching means  19  operates jointly with the display switching operation button  3 . A shutter control means  20  comprises a shutter open/close control circuit  20   a  and a shutter driving circuit  20   b  for receiving signals from the shutter open/close control circuit  20   a  and the dividing circuit  15   b . A shutter device  21  includes the light modulating section  10 . 
     Operation will next be described referring to FIG.  3 . The dividing circuit  15   b  of the reference signal generation means  15  outputs a signal into the one-second pulse generation circuit  16   a  and the time counter  16   b  of the information generation means  16 . The one-second pulse generation circuit  16   a  outputs a driving signal for the analog system, while the time counter  16   b  outputs a driving signal for the digital system. 
     That is, the one-second pulse generation circuit  16   a  generates and outputs a one-second pulse to the analog display driving means  17  for driving the hands of the analog display section  4  by a motor (not shown). The time counter  16   b  generates and outputs a one-second pulse to the digital display driving means  18  for driving the digital display section  5 . The operation described thus far corresponds to that of a typical combination watch. 
     In a timepiece according to the present invention, in order to have only one of the analog and digital display sections  4 ,  5  displayed while shielding the other, the display switching operation button  3  should be pressed (see FIG. 1) to have the display switching means  19  to output a signal. In response to the signal, the shutter open/close control circuit  20   a  of the shutter control means  20  is activated, causing the shutter driving circuit  20   b  to open in synchronism with the shutter dividing circuit  15   b , so that the shutter device  21  having the light modulating section  10  is opened or shut accordingly. 
     Therefore, to read the time from the analog display section  4 , as shown in FIG.  1 ( a ), the display switching operation button  3  is pressed to have the display switching means  19  to close the shutter for the digital display section  5 . To show a digital display section only, on the other hand, as shown in FIG.  1 ( b ), the display switching operation button  3  is pressed to have the display switching means  19  to close the shutter for the analog display section  4 . Of course, the analog and digital display sections may both be displayed at the same time. 
     In the above, the display section with a closed shutter will display a mirror-like surface when a reflection type polarizer is used for the lower polarizer  13  of the light modulating section  10 , presenting a unique overall appearance of the watch. Also, besides the total shielding of either the analog or digital display section  4 ,  5 , as mentioned above, only a part of the numbers appearing in the digital display section  5  may be shielded by appropriately modifying the control program with the shutter open/close control circuit  20   a.    
     FIG. 4 is a plan view showing a wristwatch according to a second preferred embodiment of the present invention. FIG. 5 is a cross sectional view showing major elements of the watch of FIG.  4 . FIG. 6 is a schematic system diagram for the display shown in FIG.  4 . Referring to FIG. 4, a wristwatch  31  has a display section  32 , a mode operation button  33 , a start/stop operation button  34 , a reset operation button  35 , and a split operation button  36 . The display section  32  includes a time display section  37  for displaying a time of day, a chronological display section  38 , and a chronological split display section  39 . FIG. 5 is a cross sectional diagram showing the watch of FIG. 4, including a shutter function. Framing  40  of the watch holds a glass sheet  40   a  and a rear cap  40   b . The display section  32 , comprising liquid crystal cells  41 , is driven for display by a signal supplied via a conductive rubber  42  from the circuit substrate  43 . Differing from the first embodiment, the liquid crystal cell  41  serves also as a light modulating section  44  so that displaying and a shielding function can both be attained using only a single liquid crystal cell layer. Specifically, the cell  41  works as the light modulation section  44  such that the whole digit pattern in the area shown enclosed by the broken line in FIG.  4 ( a ) (all display segment electrode patterns of the liquid crystal cell) is turned off (no applied voltage state). With the above configuration, a shielded display state can be attained using a single liquid crystal layer. 
     The light modulating section  44  has a function for varying an optical axis of the light having entered from the glass  40   a  side, and a structure comprising an upper polarizer  45  and a lower polarizer  46 . At least one of the upper and lower polarizers  45 ,  46  comprises a reflection type polarizer. In the example illustrating the present embodiment, the lower polarizer  46  is a reflection type polarizer. Display shown in a display region in the light modulating section  44  is shielded with no voltage applied to the display segment electrode pattern, and display, such as letters or numbers, can be seen with voltage applied to the display segment electrode pattern as a part of the segment electrode becomes transmissive. 
     FIG. 6 mainly shows a circuitry structure employable in the present embodiment. The reference signal generation means  15 , comprising the time reference source  15   a  and the dividing circuit  15   b , corresponds to that in the embodiment illustrated by FIG.  3 . An information generation means  47 , having received a signal from the dividing circuit  15   b , outputs a signal to a time display driving means  48 , which in turn outputs a signal to the time display section  38 , which then displays a time. 
     An operation button switch means  49  operates cojointly with the respective buttons mentioned above, and is used mainly for chronological function display. A chronological display control means  50  comprises a control circuit  50   a  for receiving signals from the operation button switch means  49  and the dividing circuit  15   b , and a function display driving circuit  50   b  for receiving signals from the control circuit  50   a  and the dividing circuit  15   b . The drawing also shows a function display device  51 , which includes a light modulating section  44 . 
     Operation of this device will next be described referring to FIG.  6 . Operation on the time display section  37  side is the same as that which has already been described in regards to FIG. 3, and will thus not be described again here. Instead, operation on the function display device  51  side will next be described. 
     The time display section  37  is continuously active and displays the present time of day, such as ten twenty-six and twenty-three seconds as shown in the figure. For a user usually wish to view only the time of day, the chronological display section  38  and the chronological split display section  39  are shielded by the light modulating section (described later), presenting a mirror-like surface, as shown in FIG.  4 ( a ). 
     In order to use a chronological function, the mode operation button  33  is operated for selection of a chronological mode, upon which the control circuit  50   a  outputs a signal to the function display driving circuit  50   b  instructing it to open the shutter by the light modulating section  44  on the chronological display section  38  side. In response to the signal, the shutter which is shielding the chronological display section  38  of the function display device  51  is opened, upon which the watch is placed in a chronological function awaiting state. At the same time, the control circuit  50   a  receives a signal from the dividing circuit  15   b . A value such as 0:0:0 is displayed on the chronological display section  38 . 
     When the start/stop operation button  34  is then pressed, display of chronological is begun through operation of the operation button switch means  49  and the chronological display control means  50 . In order to also display a split time in the lapse of a predetermined time after the start of displaying of the chronological time, the split operation button  36  should be operated. Thereupon, the shutter by the light modulating section  44 , which is shielding the chronological split display section  39 , is opened, and a split time is then displayed. 
     When the split time display disappears after operation of the split operation button  36  or because a predetermined time set on a timer has passed, the chronological split display section  39  is again shielded through operation of the chronological display control means  50  to a mirror-like surface, while the chronological display section  38  remains showing an elapsed time, as shown in FIG.  4 ( b ). When the chronological function display becomes no longer necessary, pressing the mode operation button  33  will cause the chronological display section  38  to be shielded, which in turn presents mirror-like appearance. 
     FIG. 7 is a plan view showing a wristwatch according to a third preferred embodiment of the present invention. FIG. 8 is a schematic system diagram for the displaying shown in FIG.  7 . The wristwatch has a cross section with major elements similar to that shown in FIG. 5, that is, including a single liquid crystal cell layer. FIG. 7 shows an exemplary display of data bank as confidential information. The wristwatch  61  comprises a display section  62 , a memorandum retrieval operation button  63 , a search up-rolling button  64 , a search down-rolling button  65 , and a secret display operation button  66 . The display section  62  includes a search display section  68  and a confidential information display section  69  as well as a time display section  67 . 
     Referring to FIG. 8, time displaying operation is the same as that which has been described referring to FIG. 7, and is not described again here. An operation button switch means  70  controls operations of the respective buttons  63 ,  64 ,  65 . A secret display operation switch means  71  controls operation of the secret display operation button  66 . The diagram also shows a confidential information control circuit  72 . 
     A data bank control means  73  comprises a control circuit  73   a  for receiving signals from the operation button switch means  70 , the dividing circuit  15   b , and the confidential information control circuit  72 , and a data bank driving circuit  73   b  for receiving signals from the control circuit  73   a  and the dividing circuit  15   b . The drawing also shows a data bank display device  74 , which includes a light modulating section  44 . 
     Referring to FIG. 8, operation for data bank display will be described. As shown in FIG.  7 ( a ), time display is usually shown in the time display section  67 . By operating the memorandum retrieval operation button  63 , the button switch means  70  is caused to output a signal into the control circuit  73   a . The control circuit  73   a  then outputs a signal to the data bank driving circuit  73   b  for the light modulating section  44  on the search display section  68  side to open the shutter, in response to which that shutter which is shielding the search display section  68  is opened. 
     Here, by operating the search scrolling buttons  64 ,  65 , a desired name, e.g., “LIZ”, is selected and displayed on the search display section  68  via the operation button switch means  70 . The confidential information display section  69  is kept shielded while searching, presenting mirror-like appearance, until “LIZ”, is found. Telephone numbers corresponding to respective names cannot be seen by others. 
     When the search is completed, pressing the secret display operation button  66  will cause the switch  71  to operate, and the shutter which is shielding the confidential information display section  69  is opened via the data bank control means  73  under control by the confidential information control circuit  72 . This allows the user to read the telephone number for “LIZ”. To finish the display, the buttons  66  and  63  are operated to shield the confidential information display section  69  and the search display section  68 , respectively, to have them again present mirror-like appearance. 
     FIG. 9 is a plan view showing a wristwatch according to a fourth preferred embodiment of the present invention. FIG. 10 is a schematic system diagram for the displaying shown in FIG. 9. A panel with numbered described thereon, as shown in FIG.  9 ( b ), is disposed under a liquid crystal cell as a light modulating section  86  according to a preferred embodiment other than this embodiment. FIG.  9 ( b ) is a top view of a number panel as mentioned above. The number panel  83  includes an hour number section  84  and a minute number section  85 , wherein numbers 1 and 2 and the numbers 0 through 5 are printed in the tens columns of the hour number section  84  and the minute number section  85 , respectively, and the numbers 0 through 9 are printed in the unit columns of the hour number section  84  and the minute number section  85 . 
     FIG.  9 ( c ) is a top view of a light modulating section. The light modulating section  86  comprises two and ten hour windows  87  for the tens and unit columns, respectively, and six and ten minute windows  88  for the tens and unit columns, respectively, corresponding to the respective numbers on the number panel  83 . These windows can be opened/closed. In addition, a colon display section  89  for indicating seconds is formed between the hour windows  87  and the minute windows  88 . FIG.  9 ( a ) is a plan view showing a wristwatch. In the wristwatch  81 , the number panel  83  of FIG.  8 ( b ) and the light modulating section  86  of FIG.  9 ( c ) are arranged one on the other in this order on the rear cap between the glass sheet and the rear cap. 
     FIG. 10 is a schematic system circuit for driving the wristwatch  81 . Respective means up to the information generation means  47  involved in the driving operation correspond to those in FIG. 8, and will therefore not described again here. A shutter control means  90  comprises a shutter open/close control circuit  91  for receiving a signal from the information generation means  47 , and a shutter driving circuit  92  for receiving a signal from the shutter open/close control circuit  91  and the dividing circuit  15   b.    
     Operation according to the fourth preferred embodiment will be described using an example when the current time, measured by the information generation means  47 , is fifteen twenty-seven. With respect to that time, the shutter open/close control circuit  91  controls the shutter control means  92  such that the shutter device  86 , or a light modulating section, opens windows corresponding to “1” for the tenth column and “5” for the unit column of the hour window  87  and those corresponding to “2” for the tenth column and “7” for the unit column of the minute window  88 . 
     The colon display  89  formed on the light modulating section  86  blinks to indicate seconds. With the above arrangement, the numbers printed on the number panel  83 , or an hour minute printed panel, can be seen through the respective windows open on the shutter device  86 , and seconds can be known from the blinking colons. That is, the user can know the time as fifteen twenty-seven, as shown in the wristwatch  81  of FIG.  9 ( a ). Here, second intervals are known by means of a flashing colon. 
     FIG. 11 is a plan view showing a wristwatch according to a fifth preferred embodiment of the present invention. The wristwatch  101  of FIG. 11 may be achieved using a display section  102  of, for example, two liquid crystal cell layers. That is, the upper liquid crystal cell may be used to indicate the time by means of a hand pattern  103 , while the lower liquid crystal cell may be used to indicate the time or a time period by means of a number display section  104 . In this embodiment, a chronological time is indicated using the number display section  104 . 
     As shown in FIG.  11 ( a ), when the chronological function is not used, the number display  104  is shielded, similar to the second preferred embodiment, presenting mirror-like appearance using a reflection type polarizer employed for a light modulation section. In a chronological display state, as shown in FIG.  11 ( b ), a split time is also displayed. When the split time is not displayed, the chronological display section  104   a  alone is shown with the split display section  104   b  being shielded, similar to the second preferred embodiment. 
     As an alternative of the embodiment of FIG. 11 (though not shown), when the hand pattern  103  overlaps the number display section  104  being lit, the minute pattern  103   b , which overlaps the number display section  104 , may be shielded while the hour pattern  103   a  alone is lit. The hour pattern  103   a , or other display, can be similarly shielded, when it overlaps the number display section  104 . One alternative of the fifth preferred embodiment may be a combination watch which has hour and minute hands of analog display, instead of the hour and minute patterns  103   a ,  103   b  of liquid crystal display. 
     Here, operation of a light modulating section comprising a reflection type polarizer, an absorption type polarizer, and a liquid crystal cell will be described. With a reflection type polarizer, a vibration panel (a reflection axis) orthogonal to a light transmission facilitation axis is a sheet for light reflection. With an absorption type polarizer, a vibration panel (an absorption axis) orthogonal to a light transmission facilitation axis is a sheet for light absorption. Therefore, when reflective and absorptive polarizers are arranged above and below the light modulating section comprising liquid crystal cell, a ratio between the transmission and reflection rates can be varied by rotating the light axis of the light having entered from the outside into the liquid crystal cell. 
     DBEF (trademark) optical film manufacture by Sumitomo 3M is one commercially available material suitable for a reflection type polarizer. A combination of a metal grid type polarizer (a metal grid of 0.2 μm pitch formed on a glass sheet), liquid crystal, and a phase difference panel can also realize such a panel. 
     That is, when the respective polarizers are arranged such that their transmission facilitation axes are set orthogonal to each other (in other words, the reflection axis of the reflection type polarizer and the absorption axis of the absorption type polarizer are set orthogonal to each other), the light having entered the light modulating section is reflected, presenting a metal-like reflection surface. 
     On the other hand, when the transmission facilitation axes of the reflection type and absorption type polarizers are arranged in parallel to each other (in other words, the reflection axis of the reflection type polarizer and the absorption axis of the absorption type polarizer are set in parallel to each other), the light having entered the light modulating section passes therethrough. 
     This will be described in further detail referring to FIG.  12 . 
     FIG. 12 is a cross sectional view showing an LCD device using a reflection type polarizer. 
     A typical polarizer  221  (hereinafter referred to as a normal polarizer) has a transmission axis in the direction  221   a . Liquid crystal molecules  222   a  are arranged spirally in the liquid crystal cell, as shown in FIG.  12 . 
     When a voltage is applied, the liquid crystal molecules  222   a  of the liquid crystal cell  222  change their vertical orientation. 
     A reflection type polarizer  223  has a transmission axis  223   a  and a reflection axis  223   b.    
     A blue reflection panel  224  reflects received light with a blue wavelength. 
     In a normal state as shown in FIG. 12, when light enters the polarizer  221  from thereabove, only the portion thereof in the direction of the transmission axis  221   a  reaches the liquid crystal cell  222 , with the rest being absorbed by the normal polarizer  221 . 
     The light having reached the liquid crystal cell  222  is rotated by 90 degrees by the liquid crystal molecules  222   a  before reaching the reflection type polarizer  223 . 
     In the reflection type polarizer  223 , as the direction of the reflection axis  223   b  thereof is coincided with that of the received light, the received light is reflected and reaches the liquid crystal cell  222 . 
     The liquid crystal molecules  222   a  of the liquid crystal cell  222  again rotates the light by 90 degrees, so that the rotated light reaches the normal polarizer  221  in the same direction as that of transmission axis  221   a  of the normal polarizer  221 . 
     As a result, the received light is reflected intact, which causes the entire liquid crystal device to have a mirror-like (hereinafter referred to as metal-like) appearance when viewed from thereabove. 
     However, when a voltage is applied to the liquid crystal cell  222 , the liquid crystal molecule  222   a  of the liquid crystal cell  222  rise vertically. Therefore, the light having entered via the upper surface of the device proceeds through the normal polarizer  221  only in the direction of the transmission axis  221   a , reaching intact the reflection type polarizer  223 . The reached light further proceeds through the reflection type polarizer  223  as it directs in the same direction as that of the transmission axis  223   a  of the reflection type polarizer  223  until it reaches the blue reflection panel  224  and is then reflected as blue light. 
     The reflected blue light proceeds intact through the liquid crystal cell  222  and then the polarizer  221 . 
     Therefore, the light appears blue in this case. 
     That is, when the time is displayed using the above LCD device, only the black parts in FIG. 14 appear blue, with other segment electrode patterns as well as the background  200  appear metal-like. 
     A sixth preferred embodiment of the present invention will be described, referring to FIG. 13, wherein the present invention is realized in the form of an electronic watch with LCD display. 
     The drawing shows an oscillation circuit  301  for outputting a reference signal, a dividing circuit  302  for dividing a reference signal, a time signal preparation circuit  303  for outputting a time signal, a driving circuit  304  for driving a liquid crystal device, and a liquid crystal device  305  for showing a time. 
     The drawing additionally shows an external switch  306  and a control circuit  307  for controlling the driving circuit  304  in response to operation of the external switch  306 . 
     Operation of the sixth preferred embodiment will be described referring to FIGS. 13 and 15, using an example wherein the time of day is twelve thirty-four. 
     The time signal preparation circuit  303  prepares a time signal utilizing a dividing signal from the dividing circuit  302 , and sends it to the driving circuit  304 . The driving circuit  304  prepares a driving signal for driving a segment, based on the time signal. However, when the external switch  306  is not operated, the LCD device  305  displays nothing under control by the control circuit  307  so as not to generate any driving signal. 
     Therefore, the LCD device  305  continuously appears metal-like. 
     Here, when the user wishes to know a time and operates the external switch  306 , the control circuit  307  controls the driving circuit  304  so as to validate the segments  341 ,  342 , as shown in FIG.  15 . 
     Therefore, a voltage is resultantly applied to the segments  341 ,  342 , as shown in FIG.  15 ( b ), which thereupon turn appear blue. 
     After 0.25 seconds, the control circuit  307  validates the segments  343 ,  344 ,  345 . However, as the driving circuit  304  supplies a driving signal only to the segment  344 , the segment  344  alone becomes blue with the other two remaining in metal-like appearance, as shown in FIG.  15 ( c ). 
     After another 0.25 seconds, the control circuit  307  validates the segments  346 ,  347 . However, as the driving circuit  304  supplies a driving signal only to the segment  346 , the segment  346  alone becomes blue with the other two remaining in metal-like appearance, as shown in FIG.  15 ( d ). 
     In this manner, numerals for time indication are gradually displayed from the smallest time unit as if a metal-like shutter were gradually opened, revealing the underlying numbers for time. After the elapse of a predetermined time (e.g., 10 seconds) after all required segments for the time indication have been displayed, the control circuit  307  controls the driving circuit  304  so as to top outputting of a driving signal, so that the display returns to its original metal-like appearance. 
     A seventh preferred embodiment of the present invention will be described referring to FIGS. 13 and 16. 
     A circuit block diagram for the LCD electronic watch in the seventh preferred embodiment is the same as that referred to in the sixth preferred embodiment, or that shown in FIG.  13 . 
     The watch in the seventh preferred embodiment usually remains as in the sixth preferred embodiment. 
     When the external switch  306  is once activated for time display, the control circuit  307  validates the upper half of the segments, those above the broken line in FIG.  16 ( a ), whereby the LCD device  305  appears as is shown in FIG.  16 ( b ). Subsequently, the control circuit  307  invalidates the upper half of the segments in FIG.  16 ( a ), and simultaneously validates the lower half thereof, whereby the LCD device  305  appears as is shown in FIG.  16 ( c ). 
     The above operation is carried out periodically as predetermined, which enables time displaying in a manner similar to that by a rotary-type display device, such as a display board installed in an airport or the like. After a predetermined time (e.g., five seconds), the upper and lower segments are both validated to indicate the time. 
     After a further predetermined time (e.g., ten seconds), the control circuit  307  controls the driving circuit  304  so as to stop outputting of a driving signal. Thereupon, the watch returns to present its original metal-like appearance. 
     It should be noted that the present invention is not limited to the above described seventh preferred embodiment. A displaying manner similar to that for a rotary-type display device can be achieved through modification in which a period of time for the upper and lower segments to blink is set to be gradually reduced. 
     A modified seventh preferred embodiment in which a blinking frequency for the display device is gradually lowered will be described as an eighth preferred embodiment with reference to FIGS. 17 and 18. 
     FIG. 17 is a circuitry block diagram showing the eighth preferred embodiment with detailed description of the control circuit  307  and the driving circuit  304  of FIG.  13 . 
     Selectors  701 ,  702  selectively output either of input A or B based on a signal supplied to the C terminal. 
     Respective timers  703  through  706  continually output an H-level signal during a period from turning-on of the external switch  306  to the lapse of a predetermined time. In this embodiment, the predetermined time is set at 15 seconds, 25 seconds, 30 seconds, and 60 seconds for the timers A, B, C, and D, respectively. 
     The drawing shows AND gates  707  to  710  and inverters  711  to  713 . 
     An upper segment driving circuit  741  drives the respective segments above the line  451  in FIG. 16, while a lower segment driving circuit  742  drives the respective segments therebelow. 
     Operation of this embodiment will be described referring to FIGS. 17,  18 . FIG. 18 is a time chart indicative of driving signals S 71 , S 72 , which are to be output from the control circuit  307  to the driving circuit  304 . 
     When a user wishes to know the time and operates the external switch  306 , the timers  703  through  706  output H-level signals. Thus, the selector A  701  selects a signal of 32 Hz and outputs the signal intact to the selector B. The selector B in turn outputs the received 32 Hz signal intact. As the timers  705 ,  706  also output H-level signals, the control circuit  307  outputs driving signals S 71 , S 72 , as shown in FIG. 18, to the driving circuit  304 . As the segment driving circuits  741 ,  742  drive segments only while they receive an H-level driving signals S 71 , S 72 , the upper and lower segments are alternatingly driven. Note that those segments which are then driven are only those effective for time indication. 
     After a set period, such as fifteen seconds, the timer A  703  expires and the output therefrom becomes L-level. Then, the selector A 701  outputs a signal of 16 Hz. As the other timers B, C, D  704 ,  705 ,  706  continue to output “H” level signals, the control circuit  307  outputs a 16 Hz signal, as indicated after the 15 second line in FIG.  18 . Therefore, the respective segments in the display device are alternatingly driven in a 16 Hz cycle. 
     In a further ten seconds, the timer B  704  expires and outputs an L-level signal. Accordingly, the respective segments in the display device are alternatingly driven in a 16 Hz cycle. 
     In a still further five seconds, timer C  705  expires and outputs an L-level signal. Accordingly, the AND gates  707 ,  708  output an L-level signal. Therefore, the control circuit  307  outputs an L-level signal for both upper and lower segments of the display device, as shown after the 30-second line in FIG.  18 . This state remains in sixty seconds until time is up for the timer D  706 . After another thirty seconds, output of a driving signal is suspended, and the display device then returns to the initial state. 
     In the above, a not-limiting preferred embodiment has been described in which a driving cycle for the display device becomes gradually longer. Alternatively, various other modification can be made to a cycle by providing a larger number of timers, selectors, and so on. Changing a time to set on the respective timers may also effective to add more variation in a displaying manner. 
     The present invention is also not limited to the structure shown in FIG.  16 ( a ), in which the central segments in contact with the broken line  451  are grouped into the lower segment group. These segments may be grouped into the upper segment group, or may be operated all the time as long as a driving signal is output from the driving circuit  304 . 
     Further, differing from the above, in which all segments are turned off immediately after all segments are lit, the frequency may be gradually increased to thereby turn off all segments. In addition, a frequency (cycle) variation pattern for lighting can be freely changed. Still further, segments may be divided not only into upper and lower groups, but also to right and left groups, or even into more than two groups. In this case, the respective groups may be sequentially driven. 
     The present invention is not limited to an arrangement for displaying hours and minutes only, as is described in the sixth, seventh, and eighth preferred embodiments. Similar control can be applied also in displaying any information other than time, such as seconds and dates. 
     The present invention is not limited to a blue reflection panel as shown in FIG. 12, and a reflection type polarizer may be disposed on the upper surface of the liquid crystal cell. 
     Differing from the sixth, seventh, and eighth preferred embodiment, in which any not-driven segments and background  200  are arranged to present metal-like appearance in contrast to the driven segments, an opposite manner of displaying may also be achievable by rotating the positional relationship between the polarizer  221  and the reflection type polarizer  223  by 90 degrees from that is shown in FIG. 12 (i.e., by setting the transmission axis  221   a  of the normal polarizer  221  and the reflection axis  223   b  of the reflection type polarizer  223  in parallel to each other). 
     An emission element such as an EL panel may be employed rather than reflection panel described above. With this arrangement, the emission element is driven in conjunction with a switch for retrieving time information or the like, which is also effective to suppress a power consumption increase. 
     Instead of using a switch to retrieve time information, as in the above, a switch may be used to activate other functions (e.g., an alarm time, or the like) while the time is continuously displayed. 
     Though the sixth, seventh, and eighth preferred embodiments were described using examples wherein liquid crystal cell segments were controlled for time display, similar display can be achieved with provision of a dedicated liquid crystal cell for display shielding. 
     In the above description, an electronic watch is used as an example of a popular portable electronic device. However, the present invention is not limited to an electronic watch, and obviously may be applied to various other devices with displays, such as pagers, electronic datebooks, game devices, calculators, portable telephones, and on the like, without departing from the scope of the present invention. 
     Industrial Applicability 
     As described above, the present invention is applicable to any electronic devices having a display, such as a wristwatch, pager, electronic datebook, portable telephone, or any other compact information device.