JPS648345B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for driving a display device such as a bar graph. Currently, bar graph display devices using liquid crystals are used in a wide variety of fields, and examples include the following. For example, FIG. 1 shows three columns of display sections S ₁ , S ₂ , S ₃ that display independent data, and in order to reduce the number of lead wires, each segment electrode group S ₁₁ ...S ₁₆ ,S ₂₁ ...
Connect S ₂₆ , S ₃₁ , and S ₃₆ to 10 lead wires as shown in Figure 2.
P ₁ ...Connected with P ₁₀ . Each segment electrode group
a ₁₁ ...S ₁₆ , S ₂₁ , ...S ₂₆ , S ₃₁ ...S ₃₆ are respectively connected to the common electrodes C ₁₁ ...C ₁₆ , C ₂₁ ...C ₂₆ ,
C ₃₁ ...C ₃₆ are opposed to each other with a liquid crystal (not shown) interposed therebetween. Conventionally, the following methods have been used to drive the display device. For example, when displaying as shown in FIG. 1, display blocks B ₁₃ , B ₁₄ , B ₁₅ , which deselect all display segments are used.
Common electrode of B ₁₆ , B ₂₅ , B ₂₆ , B ₃₄ , B ₃₅ , B ₃₆
Lead wires of C _{13 ,} C ₁₄ , C ₁₅ , C ₁₆ , C ₂₅ , C ₂₆ , C ₃₄ , C 35 , _C 36 q 13 , q ₁₄ , q ₁₅ , q ₁₆ , q 25 , _{q 26 ,} q _{34 ,}
The control signal a ₁ shown in FIG. 4 is constantly supplied to q ₃₅ . Also, the common electrodes C ₁₁ , C ₂₁ , C ₂₂ , C ₂₃ , C ₃₁ , C ₃₂ of the display blocks B ₁₁ , B ₂₁ , B ₂₂ , B ₂₃ , B ₃₁ , B ₃₂ which should select all the display segments Lead
Control signal _a2 is constantly supplied to _q11 , _q21 , _q22 , _q23 , _q31 , and _q32 . Furthermore, a display segment B ₁₂ in which display segments to be selected and display segments that are not selected are mixed,
Common electrode of B ₂₄ and B ₃₃ Lead wire of C ₁₂ , C ₂₄ and C ₃₃
The control signal a ₃ is sequentially supplied to q ₁₂ , q ₂₄ , and q ₃₃ in a time-sharing manner, and the control signal a ₁ is supplied at other times. For example, at time t ₁ , the control signal a ₃ is supplied to the common electrode C ₁₂ , and the control signal a 1 is supplied to the common electrodes C ₂₄ and C ₃₃ , and at time t ₂ , the control signal a ₃ is supplied to the common electrode C ₂₄ . A ₃ is supplied to common electrodes C ₁₂ , C ₃₃
is supplied with a control signal _a1 . At time _t3 , the control signal _a3 is supplied to the common electrode _C33 , and the control signal _a1 is supplied to the common electrodes _C12 and _C24 . On the other hand, control signals _{a4 and a5} are selectively applied to the lead wires P1... _P10 in FIG. 2 in synchronization with the supply of the control signal _a3 to the common electrodes _C12 , _C24 and _C33 . supply. That is, at time t ₁ , the lead wires P ₁ ,
Supply control signal _a5 to _P2 , _P3 , lead wire _P4 ...
A control signal _a4 is supplied to _P10 . As a result, the non-response signal _a7 is applied to the upper three display segments _of the display block B12 , and the response signal a8 is applied to the other display segments. One-sided display block B
A non-response signal _a8 or _a9 is applied to the display segments _{24 and} B33 . Also, at time _t2 , by supplying the control signal _a5 to the lead wires _P1 ... _P5 and supplying the control signal _a4 to the lead wires _P6 to _P10 ,
A response signal _a6 is applied to the lower five display segments _of the display block B24 , and a non-response signal _a7 is applied to the other display segments. At this time, display block B
₁₂ , B33 display segments have non _- response signals _a8 , _a9
is applied. Furthermore, at time _t3 , by supplying the control signal _a4 to the lead wires _P1 , _P2 and the control signal _a5 to _the lead wires _P3 ... _P10 , the lower two display segments of the display block B33 are A response signal _a6 is applied, and a non-response signal _a7 is applied to the other display segments. At this time _, either non-response signal _a8 or _a9 is applied to the display segment of display block B12 _or B24 . Display block to be selected on the other hand, B ₁₁ , B
₂₁ , B22 , B23 _, B31 _, and B32 _{are always} applied with either response signal _{a10 or a11 ,} and unselected display blocks B13 , B14 , _B15 , B16 , _and B _{twenty five} ,
One of the non-response signals a ₈ and a ₉ is applied to the display segments B ₂₆ , B ₃₄ , B ₃₅ , and B ₃₆ . However, this requires a decoder and drive circuit for common electrode selection for each display section.
The circuit configuration was complicated. Furthermore, in order to make all the effective values of the voltages applied to the display segments to be selected _equal , as is clear from FIG. √83)・V is included. If these voltages were to be obtained by resistor division, it would be necessary to make the dividing resistor sufficiently smaller than the resistance value of the liquid crystal, which was undesirable because the current consumption by the resistor would increase. Furthermore, it is necessary to change the waveform of the control signal _a2 depending on the number of display sections. In other words, when the number of display sections changes, the effective value of the voltage applied to the display segment to be selected in the display block where selection and non-selection are mixed changes, and the effective voltage value of the response signals a ₁₀ and a ₁₁ is kept the same. This is because it has to be done. Therefore, each time the number of display sections changes, the configuration of the control signal generation circuit must be changed. Therefore, the present invention simplifies the circuit configuration by sequentially selecting and driving a plurality of display sections in a time-sharing manner, and even when the number of display sections changes, a common control signal can be used, and the signal is supplied to each electrode. By configuring the control signal with a voltage that is an integral multiple of the predetermined voltage, the power supply circuit can be simplified and the operating margin can be increased by √
It is designed to be as large as (8+N)/N. An embodiment of the present invention will be described below based on the drawings. In Figure 5, OSC is an oscillator, D is a frequency divider,
RC is a ternary ring counter, and the display section S ₁ ,
S ₂ and S ₃ are selected in a time-sharing manner. PG is a signal generation circuit, RS ₁ , RS ₂ , and RS ₃ are registers that store the first data of display units S ₁ , S ₂ , and S ₃ respectively, and RS ₄ , RS 5 , and RS ₆ are registers that store the first data of display units S 1 , S ₂ , and S 3 respectively. ₁ , _S2 ,
This is a register that stores the 10th data of _S3 .
SE ₁ and SE ₂ are selection circuits, DE ₁ and DE ₂ are decoders,
CT is a control circuit. PS ₁ , PS ₂ are signal selection circuits, SW ₁ , SW ₂ are signal selection circuits, SW ₁ , SW ₂ ,
SW ₃ is a switching circuit. In the above configuration, the terminal S of the signal generation circuit PG
off, S on, C off, C mix, and C on are the segment electrode non-selection signals shown in Figure 6, respectively.
_a5 , segment electrode selection signal _a4 , common electrode signal _a3
and a common electrode all selection signal _a12 is set to be generated. All of the above signals have a voltage of 0, V,
Since it is configured with either 2V or 3V,
Power supply can be simplified. Moreover, the signals a ₁ , a ₃ , a ₄ , a ₅
are all at the same potential (in this example, 4 to 6 scales from the left in the figure) at the same timing (in this example, 4 to 6 scales from the left in the figure).
0), and only the signal _a12 is configured to have a different potential at the above timing. Now, at time t ₁ , when a pulse is generated from terminal r ₁ of ring counter RC, registers RS ₁ and RS ₄
The outputs of are selected by selection circuits SE ₁ and SE ₂ , respectively, and supplied to decoders DE ₁ and DE ₂ . The signal selection circuit PS ₂ selects the signals a ₁ , a ₃ , a ₁₂ shown in FIG. 6 based on the output of the decoder DE ₂ and supplies them to the switching circuits SW ₁ , SW ₂ , SW ₃ . The signal from the signal selection circuit PS ₂ passes through the switching circuit _{SW 1 due} to the above-mentioned pulse from the terminal r 1 and is supplied to the common electrodes C ₁₁ . . . C ₁₆ in FIG. 3. On the other hand, the switching circuits SW ₂ and SW ₃ generate a common electrode non-selection signal a ₁ from the terminal C off, and the common electrode non-selection signal a 1 in FIG.
C ₂₁ ... C ₂₆ , C ₃₁ ... C ₃₆ are supplied. For example, when displaying as shown in Fig. 1, the common electrode C ₁₃ ...C ₁₆
A common electrode non-selection signal _a1 is supplied to the common electrode _C12 , a common electrode selection signal _a3 is supplied to the common electrode C11, and a common electrode full selection signal _a12 is supplied to the common electrode _C11 . In addition, the output of the decoder DE ₁ is supplied to the control circuit CT, and when the data at the 10th place is an even number, the output from the terminal d ₁ ...
The outputs from d ₁₀ appear on terminals e ₁ ... e ₁₀ , respectively,
When the data in the 10th place is an odd number, the terminal d ₁ ... d ₁₀
The outputs from the terminals e ₁₀ ... e ₁ are generated respectively. This is because each segment electrode group is connected in a zigzag manner with a common lead wire P ₁ ... P ₁₀ .
This is because the lead wires P ₁ ...P ₁₀ are connected in the reverse order in the even-numbered segment electrode groups and the odd-numbered segment electrode groups. Now, depending on the output from the control circuit CT, the signals a ₄ and a ₅ shown in FIG. 6 are selectively generated from the signal selection circuit PS ₁ . When performing the display shown in Figure 1, segment electrode non-selection signals are connected to lead wires P ₁ , P ₂ , and P _3.
The segment electrode selection signal _a4 is supplied to the lead wires _P4 ... _P10 . Therefore, either response signal a ₁₃ or a ₁₄ is applied to each display segment of display block B ₁₁ , and either non-response signal a ₈ or a ₉ is applied to the display segment of display block B ₁₃ ... B ₁₆ . is applied. Further, a non-response signal _a7 is applied to the upper three display segments _of the display block B12 , and a response signal _a6 is applied to the lower seven display segments. On the other hand, since the common electrode non-selection signal a ₁ is supplied to each common electrode of the display sections S ₂ and S ₃ , either the non-response signal a ₈ or a ₉ is applied to each display segment. Next, at time _t2 , when a pulse is generated from terminal _R2 of ring counter RC, registers _RS2 ,
The output of RS ₅ is selected, and signals a ₄ and a ₅ are selectively supplied to leads P _{1 .} . . P ₁₀ based on the data of register RS ₂ . On the other hand, the output of the signal selection circuit PS ₂ is connected to the common electrode C ₂₁ through the switching circuit SW ₂ ...
C ₂₆ and the common electrode C ₁₁ ... C ₁₆ , C ₃₁ ...
A common electrode non-selection signal _a1 is supplied to _C36 . Therefore, a signal corresponding to the data is applied to each display segment of the display section _S2 , and one of the non-response signals _a8 and _a9 is applied to each display segment of the display sections _S1 and _S3 . be done. Furthermore, at time _t3 , when a pulse is generated from the terminal _r3 of the ring counter RC, the display section _S3 is selected and the non-response signals _a8 , _a9 are applied to the display sections _S1 , _S2 . The above operation is repeated, and the display parts S ₁ , S ₂ ,
S ₃ is selected in a time-sharing manner. Here, the signal applied to each display segment is
Taking time T = t ₁ + t ₂ + t ₃ as one period, looking at the effective voltage values, the values of the unselected display segments are all 1/√2・V, and the values of the display segments to be selected are all √116・V. V, the ratio of the two is √113, and sufficient contrast can be obtained. In FIG. 7, _a common electrode full selection signal a ₁₅ is used in place of the common electrode full selection signal a ₁₂ in FIG. As a result, response signals a ₁₆ and a ₁₇ having exactly the same effective values as the response signals a ₁₃ and a ₁₄ are obtained. By the way, in the above embodiment, there are three display parts S ₁ ,
Although the case of driving S ₂ and S ₃ has been described, it may also be used to drive two display sections. In this case, each signal may be exactly the same as above, and the effective values of the voltages applied to the selected and non-selected display segments will be √52 and 1/√2, respectively.
The ratio between the two is √5. It may also be used to drive four or more display sections, and in this case, each signal may be exactly the same as above, and when the number of display sections is N, selection and non-selection display The effective value of the voltage applied to each segment is √
It is expressed as (8+N)/2N·V, 1/√2, and the ratio between the two is expressed as √(8+). Figures 8 and 9 show other examples of signals supplied to each electrode, and each signal is composed of 0, V, 2V, 3V, or 4V. , the effective values of the voltages applied to the selected and unselected display segments are the same as in the above embodiment. Moreover, in each example, the common electrode non-selection signal, the common electrode selection signal, the segment electrode selection signal, and the segment electrode non-selection signal have portions that are at the same potential at the same timing, and only the common electrode full selection signal is as described above. They are configured to have different potentials at different timings. Although the above embodiment describes driving a bar graph display device, the present invention is not limited to this, and the present invention may be used to display hours, minutes, etc. by arranging two display portions concentrically. As detailed above, according to the present invention, a plurality of display sections are selected in a time-sharing manner, and a signal consisting of a predetermined voltage and a voltage that is an integral multiple thereof is selectively supplied to each common electrode and each segment electrode. A response signal and a non-response signal each having a constant voltage effective value were selectively applied, and the ratio of the voltage effective value of the response signal and non-response signal was set to √(8+) (N is the number of display sections). , the power supply circuit can be simplified, the operating margin can be increased, and a high contrast display without crosstalk can be performed. Moreover, even if the number of display sections changes, there is no need to change the signal waveform, so there is no need to change the design of the control signal generation circuit.

[Brief explanation of drawings]

Figure 1 is a front view showing an example of a display device, Figure 2 is a front view showing an example of a display device;
3 and 3 are explanatory views showing the segment electrodes and common electrodes of the display device shown in FIG. 1, respectively, FIG. 4 is an explanatory view showing signal waveforms according to the conventional driving method, and FIG. A block diagram showing the circuit configuration of the embodiment and FIGS. 6 to 9 are explanatory diagrams showing signal waveforms according to the present invention, respectively. S ₁ , S ₂ , S ₃ ...display section, B ₁₁ to B ₁₆ , B ₂₁ to B
₂₆ , B31 _to B36 ...display block, _{S11 to S16} , _S21
〜S ₂₆ , S ₃₁ 〜S ₃₆ ...Segment electrode group, C ₁₁ 〜
C ₁₆ , C ₂₁ ~ C ₂₆ , C ₃₁ ~ _{C 36} ... Common electrode, a ₁ ...
Common electrode non-selection signal, a ₃ ... common electrode selection signal,
a ₄ ... Segment electrode selection signal, a ₅ ... Segment electrode non-selection signal, a ₁₂ , a ₁₅ ... Common electrode all selection signal, a ₆ , a ₁₃ , a ₁₄ , a ₁₆ , a ₁₇ ... Response signal , a ₇ ,
_a8 , _a9 ...Non-response signal.

Claims (1)

[Scope of Claims] 1. N (N is an integer of 2 or more) display blocks each including a common electrode and a group of segment electrodes facing the common electrode via a liquid crystal to perform integrated display. It has a display section, each segment electrode group is connected by a common lead wire, each of the display sections is sequentially selected in a time-sharing manner, and voltages of 0, V, and 2V are applied to the common electrode of the selected display section. ,
A common electrode non-selection signal a ₁ consisting of at least any two voltages among nV (n=3, 4...),
Common electrode selection signal a ₃ and common electrode all selection signal
Either a ₁₂ or a ₁₅ is selectively supplied, and the voltages 0, V, 2 V, . . . are applied to the segment electrodes.
A response signal is applied to a desired liquid crystal by selectively supplying a segment electrode selection signal _a4 and a segment electrode non-selection signal _a5 consisting of at least any two voltages of nV (n=3, 4...). , the common electrode non-selection signal a ₁ is supplied to _each common electrode of the non-selected display section, and a non-response signal is applied to all of the liquid crystals; The common electrode selection signal a ₃ , the segment electrode selection signal a ₄ and the segment electrode non-selection signal a ₅ all have portions that are at the same potential at the same timing, and the common electrode all selection signals a ₁₂ and a ₁₅ is a different potential from the same potential at the above timing, and is caused by the potential difference between the common electrode non-selection signal _a1 , the segment electrode selection signal _a4 , and the segment electrode non-selection signal _a5 . The non-response signal applied to the liquid crystal due to the potential difference between the common electrode selection signal _a3 and the segment electrode non-selection signal _a5 have the same effective voltage value. A response signal applied to the liquid crystal due to the potential difference between the common electrode all selection signals _a12 , _a15 , the segment electrode selection signal _a4 and the segment electrode non-selection signal _a5 , and the common electrode selection signal _a3. and the response signal applied to the liquid crystal due to the potential difference between the segment electrode selection signal _A4 and the segment electrode selection signal A4 have the same effective voltage value, and the ratio of the effective voltage value of the non-response signal and the response signal is √(8+). A method for driving a display device, characterized in that: