JP2011158705A - Liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal display device capable of driving a liquid crystal display panel having both of segment display and dot matrix display by the minimum circuit constitution with a small current consumption. <P>SOLUTION: This device has a constitution including liquid crystal display panels 2, 3 having a segment display part 3a and a dot matrix display part 2a, a microcomputer 6 having a built-in segment driver circuit 5 for supplying a driving signal to the segment display part 3a, and a dot matrix driver IC 4 for supplying a driving signal to the dot matrix display part 2a based on a control signal of the microcomputer 6. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a liquid crystal display device for driving a liquid crystal display panel having a segment display unit and a dot matrix display unit.

  In recent years, a liquid crystal display device using a liquid crystal display panel has been used in various products. For example, a thin liquid crystal television is generally used for a large-sized device, and a watch, Used in mobile phones and electronic shelf labels. Even for small liquid crystal display devices, the amount of information to be displayed tends to increase as the functions of the mounted devices increase in performance and performance. For this reason, the drive circuit that drives the liquid crystal display panel However, it is difficult to reduce the size of the device due to an increase in the amount of wiring, and the power consumption is increased, which is a big problem particularly as a display device for a battery-driven small electronic device.

  From such a background, a driver circuit of a display device that discloses a relatively large amount of display information and reduces current consumption has been disclosed (for example, see Patent Document 1). An outline of a driver circuit of a conventional display device disclosed in Patent Document 1 will be described with reference to FIG. In FIG. 8, reference numeral 101 denotes a main body of an audio set, for example, 105 denotes a microcomputer (hereinafter abbreviated as a microcomputer), and 110 denotes a liquid crystal display panel.

  The microcomputer 105 is for controlling the main body 101 and includes a CPU, a ROM, a RAM, an input port, an output port, a clock circuit (timer circuit), etc., and is made into one chip. The microcomputer 105 is connected to the main body 101 through the port, and controls the main body 101 in accordance with a user's key operation or the like.

  The microcomputer 105 also controls display on the liquid crystal display panel 110. For this reason, the liquid crystal driver circuit 106 is built in, and some of the output ports 107 are assigned for display. Yes.

  The liquid crystal display panel 110 is signal-separated into a display unit 111 that displays even when the power is turned off and a display unit 112 that does not display when the power is turned off. Then, scanning signals and display signals for the display unit 111 are extracted from the liquid crystal driver circuit 106 of the microcomputer 105, and these scanning signals and display signals are supplied to the display unit 111.

  A single liquid crystal driver IC 115 is provided, and the port 107 of the microcomputer 105 is connected to the display unit 112 through the liquid crystal driver IC 115. Further, a switch circuit 117 is provided in a power supply line between the power supply terminal of the liquid crystal driver IC 115 and the power supply VCC, and a control signal is supplied to the switch circuit 117 from the port 107 of the microcomputer 105.

  With this configuration, when the power is turned on, the operating voltage is supplied to the main body 101 to be in an operating state, and the switch circuit 117 is turned on by a control signal from the port 107, so that the liquid crystal driver IC 115 also operates. It becomes a state.

  As a result, the display data is converted into a scanning signal and a display signal by the liquid crystal driver circuit 106 and the liquid crystal driver IC 115 built in the microcomputer 105, and the scanning signal and the display signal are supplied to the display units 111 and 112, respectively. Done.

On the other hand, when the power is turned off, the operating voltage is not supplied to the main body 101, and the switch circuit 117 is turned off by the control signal from the port 107, so that the liquid crystal driver IC 115 is also not supplied with power. However, when the power is off, the display data from the microcomputer 105 is supplied to the built-in liquid crystal driver circuit 106 and converted into a scanning signal and a display signal, and the scanning signal and the display signal are supplied to the display unit 111. The display unit 111 displays the current time, for example.

  As a result, the display driver circuit of Patent Document 1 uses two driver circuits, that is, a single liquid crystal driver IC and a liquid crystal driver circuit built in the microcomputer for the two display units. It is shown that the current consumption can be reduced because the power of the IC 115 is turned off and the display of one display unit 112 is not performed.

  In addition, a portable terminal using a self-holding type display (memory display panel) for at least a part of a display portion in order to reduce current consumption is disclosed (for example, see Patent Document 2). A part of the display part of this portable terminal is a pictotype liquid crystal display panel, and the other display part whose display changes slowly is a self-holding type liquid crystal display panel. And it has the 1st driver circuit which drives a pictotype liquid crystal display panel, and the 2nd driver circuit which drives the self-holding-type liquid crystal display panel from which a display changes slowly.

  The first driver circuit is always turned on, and the second driver circuit that drives the self-holding type liquid crystal display panel is turned on only when the display is rewritten. Thereby, the portable terminal of Patent Document 2 drives the display unit with two driver circuits, and the second driver circuit that drives the self-holding type liquid crystal display panel turns on the power only when the display is rewritten, It has been shown that current consumption can be reduced.

[Description of ferroelectric liquid crystal display panel]
Next, in order to assist in understanding the present invention, which is well known, the configuration and operation of a display panel using ferroelectric liquid crystal that realizes the memory display panel described in Patent Document 2 will be described below. Note that the memory display panel is a display panel in which display information is retained without being erased even if the drive signal is stopped after the display information is written by the drive signal, and the memory display panel of the liquid crystal display device of the present invention. Part or all is constituted by this ferroelectric liquid crystal.

  First, the structure of a memory type liquid crystal display panel having a ferroelectric liquid crystal layer will be described with reference to FIG. FIG. 9A is a plan view schematically showing the configuration of the polarizing plate arrangement of the memory-type liquid crystal display panel. The liquid crystal display panel 120 includes a polarizing plate between the polarizing plates 121a and 121b that are in crossed Nicols. One of the polarization axis C of 121a and the polarization axis D of the polarizing plate 121b, and the molecular long axis direction in the first stable state (arrow E) or the second stable state (arrow F) of the liquid crystal molecules The ferroelectric liquid crystal layer 122 is arranged so that one of them is substantially parallel. Here, in FIG. 9A, the polarizing axis 121a of the polarizing plate 121a and the molecular long axis direction in the first stable state (arrow E) are arranged so as to be substantially parallel.

  Next, FIG. 9B is a cross-sectional view schematically showing the structure of the liquid crystal display panel 120. In FIG. 9B, the liquid crystal display panel 120 includes a pair of glass substrates 123a and 123b that sandwich a ferroelectric liquid crystal layer 122 that is a memory liquid crystal having at least two stable states. Further, the glass substrates 123a and 123b are fixed by a sealing material 126. A plurality of scanning electrodes 124 as drive electrodes and a signal electrode 125 are provided on the opposing surfaces of the glass substrates 123a and 123b, and alignment films 127a and 127b are deposited thereon.

Further, on the outer side of one glass substrate 123a, as described above, the first polarization is made so that the molecular major axis direction in the first or second stable state of the liquid crystal molecules of the ferroelectric liquid crystal layer 122 is parallel. A plate 121a is provided, and a second polarizing plate 121b is provided outside the other glass substrate 123b so as to be 90 degrees different from the polarization axis of the first polarizing plate 121a.

  Next, the operation of the liquid crystal display panel 120 shown in FIGS. 9A and 9B will be described with reference to FIG. FIG. 10 shows changes in the light transmittance L (solid line) with respect to the driving voltage of the liquid crystal display panel 120. Here, the switching of the ferroelectric liquid crystal, that is, the transition from one stable state to the other stable state, applies a voltage at which the product of the pulse width value and the pulse high value of the drive voltage is equal to or greater than a threshold value. It occurs only when applied to the liquid crystal. In FIG. 10, the liquid crystal display panel 120 selects either the first stable state (non-transmission (black) display) or the second stable state (transmission (white) display) depending on the polarity of the drive voltage. Is done.

  Here, when the drive voltage is increased in the positive direction, the voltage value at which the light transmittance L starts to change is defined as + Vt, and the voltage value at which the change in the light transmittance L is saturated is defined as + Vh. Next, the drive voltage is decreased, and the voltage value is further increased in the negative direction of the reverse polarity, whereby the voltage value at which the light transmittance L starts to decrease is −Vt, and the voltage value at which the change of the light transmittance L is saturated is −Vh. . Here, ± Vt is defined as the threshold voltage of the ferroelectric liquid crystal, and ± Vh is defined as the saturation voltage.

  As described above, in the liquid crystal display panel 120, the second stable state is selected when a driving voltage equal to or higher than the saturation voltage + Vh of the ferroelectric liquid crystal is applied, and the saturation voltage −Vh having the opposite polarity of the ferroelectric liquid crystal is selected. When the above driving voltage is applied, the first stable state is selected. After that, each stable state is maintained by the memory effect even when the drive voltage becomes 0V.

  As a result, when the polarizing plates 121a and 121b are arranged as shown in FIG. 9A, white display (transmission state) is achieved in the second stable state, and black display (non-transmission state) is achieved in the first stable state. Note that by changing the arrangement of the polarizing plates 121a and 121b, black display (non-transmission state) can be achieved in the second stable state, and white display (transmission state) can be achieved in the first stable state.

  Thus, the liquid crystal display panel using ferroelectric liquid crystal can maintain the display even if the power to the liquid crystal display panel is shut off after applying the driving voltage to rewrite the display to be in a stable state. . The liquid crystal display device of the present invention can realize further power saving by using the memory type liquid crystal display panel using the ferroelectric liquid crystal for a part or all of the liquid crystal display panel to be used. Become.

Japanese Patent Laid-Open No. 6-4034 (page 3, FIG. 1) JP 2000-69134 A (page 3, FIG. 1)

  The driver circuit of Patent Literature 1 mainly divides the display unit into two in order to reduce power consumption, but the two display units are a display method for displaying a segment display or a specific figure corresponding thereto. Yes, it is not possible to display graphics with a large amount of information. Further, when the power to the microcomputer is turned off to further reduce power consumption, there is a problem that all display contents disappear. Further, in order to turn off the power supply of the external liquid crystal driver IC, a power switch circuit is necessary, and there are problems such as a large circuit scale and complicated power control.

Further, in the portable terminal of Patent Document 2, it is necessary to prepare a liquid crystal driver circuit for each of the pictotype liquid crystal display panel and the self-holding type liquid crystal display panel, and the circuit scale becomes large and it is difficult to reduce the size.

  An object of the present invention is to solve the above problems and provide a liquid crystal display device that drives a liquid crystal display panel having both a segment display and a dot matrix display with a minimum circuit configuration and low current consumption.

  In order to solve the above problems, the liquid crystal display device of the present invention employs the following configuration.

  A liquid crystal display device of the present invention includes a liquid crystal display panel having a segment display portion and a dot matrix display portion, a microcomputer incorporating a signal electrode driving liquid crystal driver circuit for supplying a drive signal to the segment display portion, and a microcomputer And a dot matrix electrode driving liquid crystal driver IC for supplying a driving signal to the dot matrix display portion based on the control signal.

  The dot matrix display unit has a ferroelectric liquid crystal layer, and the dot matrix electrode driving liquid crystal driver IC outputs a drive signal for driving the ferroelectric liquid crystal layer.

  The segment display unit has a ferroelectric liquid crystal layer, and the signal electrode driving liquid crystal driver circuit outputs a driving signal for driving the ferroelectric liquid crystal layer.

  Further, the segment display unit and the dot matrix display unit are integrated and configured by one liquid crystal display panel.

  The dot matrix electrode driving liquid crystal driver IC is mounted on a substrate of a liquid crystal display panel.

  Further, the liquid crystal display panel has a connection part for inputting a drive signal from the outside, and the connection part and the microcomputer are electrically connected by a connection member.

  Further, in the liquid crystal display panel, a dot matrix electrode driving liquid crystal driver IC is disposed near the connection portion, a dot matrix display portion is formed at a position close to the dot matrix electrode driving liquid crystal driver IC, and at a position far from the connection portion. A segment display portion is formed.

  The connecting member is a flexible substrate.

  As described above, according to the present invention, a dot matrix display section with a large number of drive signal lines is driven by a single dot matrix electrode driving liquid crystal driver IC, and a segment display section with a small number of drive signals is built into a microcomputer. By driving with a liquid crystal driver circuit, a liquid crystal panel with a large amount of display information can be controlled by a single general-purpose microcomputer and a large amount of information can be displayed. In addition, by arranging the dot matrix display section with a large number of drive signal lines close to the liquid crystal driver IC for driving the dot matrix electrode, the wiring area can be minimized, and the transmission of the drive signal is ensured and the reliability is excellent. A liquid crystal display device can be realized.

Further, by using a ferroelectric liquid crystal having a memory property, a drive signal can be stopped after display rewriting, so that a liquid crystal display device with extremely low power consumption can be realized. Further, information that is not frequently rewritten is performed in the dot matrix display unit, and information that is frequently rewritten is performed in the segment display unit, thereby realizing display quality with less flicker.

It is a block diagram explaining the structure of the 1st Embodiment of this invention. It is a block diagram explaining the structure of the 2nd Embodiment of this invention. It is a block diagram explaining the structure of the 3rd Embodiment of this invention. It is explanatory drawing of the drive electrode of the ferroelectric liquid crystal dot matrix display part of the 3rd Embodiment of this invention. It is a timing chart explaining the drive signal of the 3rd Embodiment of this invention. It is an arrangement drawing explaining an example of arrangement composition of a 3rd embodiment of the present invention. It is explanatory drawing explaining the example of a display by the liquid crystal display panel of the 3rd Embodiment of this invention. It is a block diagram explaining the structure of the conventional driver circuit. It is explanatory drawing explaining the structure of the memory-type liquid crystal display panel which has a ferroelectric liquid crystal layer. It is an operation | movement figure explaining operation | movement of the memory-type liquid crystal display panel which has a ferroelectric liquid crystal layer.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The basic configuration of the present invention is shown as the first embodiment, and the liquid crystal display device using the liquid crystal display panel having the ferroelectric liquid crystal layer in the dot matrix display portion is shown as the second embodiment. As a form, a liquid crystal display device using a liquid crystal display panel having a ferroelectric liquid crystal layer in both a dot matrix display portion and a segment display portion is shown.

  The configuration of the liquid crystal display device of the first embodiment will be described with reference to FIG. In FIG. 1, reference numeral 1 denotes a liquid crystal display device as a first embodiment. The liquid crystal display device 1 includes a liquid crystal display panel 2 having a dot matrix display portion 2a, a liquid crystal display panel 3 having a segment display portion 3a, and a dot matrix electrode driving liquid crystal driver IC 4 for supplying a drive signal to the dot matrix display portion 2a. (Hereinafter abbreviated as dot matrix driver IC4) and microcomputer 6 (hereinafter referred to as microcomputer) incorporating a signal electrode driving liquid crystal driver circuit 5 (hereinafter abbreviated as segment driver circuit 5) for supplying a drive signal to the segment display section 3a. 6).

  Here, the dot matrix display unit 2a is made of general twisted nematic liquid crystal (hereinafter abbreviated as TN liquid crystal) or the like, and is a well-known technique, so its structure is not shown, but the liquid crystal display panel 120 shown in the conventional example. The basic structure is the same as that (see FIG. 9B), and includes a large number of scanning electrodes and signal electrodes. Similarly, the segment display portion 3a is also made of TN liquid crystal or the like, and has fewer scanning electrodes and signal electrodes than the dot matrix display portion 2a, although not shown.

In addition to the segment driver circuit 5, the microcomputer 6 includes a CPU, ROM, RA (not shown).
M, an input port, an output port, a clock circuit (timer circuit), and the like are built in, and a control signal P1 is input from the outside to control the segment driver circuit 5 and output a dot display control signal P2 (not shown). Are supplied to the dot matrix driver IC4.

  The segment driver circuit 5 built in the microcomputer 6 receives display data from the inside of the microcomputer 6 and outputs a plurality of scanning signals CM and a plurality of display signals SG as drive signals, and the segment display unit 3a described above. To supply. The dot matrix driver IC 4 receives a dot display control signal P 2 including display data from the microcomputer 6, converts the display data, and outputs a plurality of scanning signals MCM and display signals MSG as drive signals. It supplies to the matrix display part 2a.

  The microcomputer 6 and the dot matrix driver IC 4 are driven by inputting the power supply VDD from the outside. The microcomputer 6 operates by being supplied with the power supply VDD, and controls the segment driver circuit 5 and the dot matrix driver IC 4 which are separate chips based on the control signal P1, and the segment display unit 3a and the dot matrix display unit. Various information is displayed in 2a.

  The two liquid crystal display panels 2 and 3 may be separated as shown, or may be a combination of the liquid crystal display panels 2 and 3. The dot matrix display unit 2a and the segment display unit 3a have been described as TN type liquid crystal display panels, but it is needless to say that other types of liquid crystal panels are also applicable.

  As described above, in the liquid crystal display device 1 of the present embodiment, the dot matrix display unit 2a having a large number of drive signals is driven by the dot matrix driver IC 4, and the segment display unit 3a having a small number of drive signals is incorporated in the microcomputer 6. By driving with the circuit 5, a liquid crystal panel with a large amount of display information can be controlled by one general-purpose microcomputer and a large amount of information can be displayed.

  Here, assuming that the dot matrix display unit 2a is a display unit having a pixel number of 128 dots × 160 dots as an example, the number of drive signals required by the dot matrix display unit 2a is 128 scanning signals MCM. The number of display signals MSG is 160, which is 288 in total. Assuming that a liquid crystal display panel that requires a large number of drive signals is directly driven by a single microcomputer, the microcomputer requires a large number of output ports and a large-scale liquid crystal driver circuit. It cannot be used, and it becomes necessary to develop a large-scale custom microcomputer, and the development period and development cost become problems.

  Further, since the number of output pins of the microcomputer is large, the package becomes large, and it is difficult to reduce the size of the liquid crystal display device. In addition, the number of wires for electrically connecting the microcomputer and the display unit becomes enormous, which causes problems such as an increase in the cost of a flexible substrate for connection and a decrease in connection reliability. Also, the fact that general-purpose microcomputers cannot be used is disadvantageous when changing product specifications or product lineups, and even with slight changes in specifications, it is necessary to recreate a custom microcomputer, which is a major problem.

However, in the liquid crystal display device of this embodiment, only the segment display unit 3a having a small number of drive signals is directly driven from the microcomputer 6, and the dot matrix display unit 2a having a large number of drive signals is driven by a dot matrix driver IC4 which is a separate chip. Since it is driven, the microcomputer 6 does not need a large number of output ports and a large-scale driver circuit, and the microcomputer can use a general-purpose microcomputer incorporating a general liquid crystal driver circuit. Also, as the dot matrix driver IC 4, many general-purpose liquid crystal driver ICs with multiple outputs have been commercialized. Therefore, the general-purpose liquid crystal driver IC may be selected and used in consideration of the necessary number of drive signals. The dot matrix driver IC 4 is mounted on a glass substrate of a liquid crystal display panel and a drive signal wiring can be formed on the glass substrate, which will be described later. Therefore, high-density mounting and high-density wiring are possible.

  Therefore, the liquid crystal display device of the present embodiment is a minimum in driving a liquid crystal display panel having both a segment display unit and a dot matrix display unit with a large amount of display information in combination with a general-purpose microcomputer and a general-purpose liquid crystal driver IC. The circuit configuration has great effects such as downsizing, high reliability, shortening the development period, and low price.

  Next, the configuration of the liquid crystal display device of the second embodiment will be described with reference to FIG. In the present embodiment, an FLC liquid crystal display panel using a ferroelectric liquid crystal layer in either the dot matrix display section or the segment display section is employed. Here, a case where an FLC liquid crystal display panel is used for the dot matrix display portion will be described. In FIG. 2, reference numeral 10 denotes a liquid crystal display device as a second embodiment. The liquid crystal display device 10 includes a ferroelectric liquid crystal dot matrix display unit 12 (hereinafter abbreviated as FLC dot matrix display unit 12) having a ferroelectric liquid crystal layer, and a TN segment display unit 13 having a TN liquid crystal layer. A liquid crystal display panel 11, a dot matrix electrode driving ferroelectric liquid crystal driver IC 14 (hereinafter abbreviated as FLC dot matrix driver IC 14) for supplying a driving signal for driving a ferroelectric liquid crystal layer to the FLC dot matrix display unit 12; The signal electrode driving TN liquid crystal driver circuit 15 (hereinafter abbreviated as TN segment driver circuit 15) is built in a microcomputer 16 (hereinafter abbreviated as microcomputer 16).

  Here, like the liquid crystal display panel 120 (see FIG. 9B) shown in the conventional example, the liquid crystal display panel 11 has a pair of glass substrates opposed to each other with a liquid crystal layer interposed therebetween, and FLC is provided on the glass substrate. A dot matrix display unit 12 and a TN segment display unit 13 are formed. Since the FLC dot matrix driver IC 14 is mounted on the glass substrate of the liquid crystal display panel 11, the FLC dot matrix display unit 12, the TN segment display unit 13, and the FLC dot matrix driver IC 14 are used as one liquid crystal display panel 11. It is integrated.

  Further, although not shown here, the FLC dot matrix display unit 12 includes a large number of scanning electrodes and signal electrodes similarly to the dot matrix display unit 2a of the first embodiment described above. Further, the TN segment display unit 13 includes a small number of scanning electrodes and signal electrodes in the same manner as the segment display unit 3a of the first embodiment. The details of these display units will be described in the description of a third embodiment to be described later.

  As in the first embodiment, the microcomputer 16 includes a CPU, ROM, RAM, input port, output port, clock circuit (timer circuit), etc. (not shown) in addition to the TN segment driver circuit 15 and is controlled from the outside. The signal P1 is input to control the TN segment driver circuit 15, and a dot display control signal P2 is output from an output port (not shown) and supplied to the FLC dot matrix driver IC14.

  A plurality of scanning signals CM and a plurality of display signals SG are output as drive signals from the TN segment driver circuit 15 built in the microcomputer 16 and supplied to the TN segment display unit 13 described above. That is, the TN segment driver circuit 15 is a driver circuit for driving the TN segment display unit 13 made of TN liquid crystal. The FLC dot matrix driver IC 14 receives the dot display control signal P2 from the microcomputer 16, outputs a number of scanning signals FMCM and display signals FMSG as drive signals, and supplies them to the FLC dot matrix display unit 12 described above.

Further, the microcomputer 16 and the FLC dot matrix driver IC 14 are driven by inputting the power supply VDD from the outside as in the first embodiment. The microcomputer 16 operates when this power supply VDD is supplied, and controls the built-in TN segment driver circuit 15 and the dot matrix driver IC 14 on a separate chip based on the control signal P1, and the TN segment display unit 13 and the FLC dot Various information is displayed on the matrix display unit 12.

  As described above, in the liquid crystal display device 10 of this embodiment, the FLC dot matrix display unit 12 having a large number of drive signals is driven by the FLC dot matrix driver IC 14 and the TN segment display unit 13 having a small number of drive signals is incorporated in the microcomputer 16. By driving with the TN segment driver circuit 15, a liquid crystal panel with a large amount of display information can be controlled by a single microcomputer and a large amount of information can be displayed.

  The liquid crystal display panel 11 has a FLC dot matrix display portion 12 and a TN segment display portion 13 formed on a glass substrate, and the FLC dot matrix driver IC 14 is also mounted and integrated on the glass substrate. A display device can be realized, and a large number of signal lines of the scanning signal FMCM and the display signal FMSG for electrically connecting the FLC dot matrix driver IC 14 and the FLC dot matrix display unit 12 can be formed on a glass substrate, and handling is highly reliable. Can be realized. These effects can be similarly obtained even when a ferroelectric liquid crystal layer is used for the segment display portion and a TN liquid crystal layer is used for the dot matrix display portion.

  Further, when the ferroelectric liquid crystal is used for the dot matrix display section, the FLC dot matrix display section 12 has a memory property, so that the scanning signal FMCM and the display signal FMSG are displayed only when the display changes. When supplied and the display is not changed, the FLC dot matrix driver IC 14 can be put into a pause state to stop the output of the scanning signal FMCM and the display signal FMSG. As a result, the current consumption of the FLC dot matrix driver IC 14 and the FLC dot matrix display unit 12 can be made extremely small, so that a liquid crystal display device with a particularly low current consumption can be realized and effective.

  The FLC dot matrix display unit 12 having a memory property displays information with a low frequency of rewriting the display, and the TN segment display unit 13 without a memory property displays information with a high frequency of display rewriting such as a time display. Therefore, it can be used according to the characteristics of each display panel.

  Further, since the microcomputer 16 may be a microcomputer incorporating a driver circuit for driving a general TN liquid crystal, a general-purpose microcomputer can be used as in the first embodiment. The FLC dot matrix driver IC 14 is a driver IC that drives ferroelectric liquid crystal. However, since a general-purpose driver IC for ferroelectric liquid crystal is available in recent years, the FLC dot matrix driver IC 14 is also available. A general-purpose driver IC can be used. As a result, this embodiment can also be realized by combining the general-purpose microcomputer and the general-purpose liquid crystal driver IC, and thus has various effects as in the first embodiment.

[Configuration Description of Liquid Crystal Display Device of Third Embodiment: FIG. 3]
Next, the configuration of the liquid crystal display device of the third embodiment will be described with reference to FIG. Since the basic configuration of the third embodiment is the same as that of the second embodiment described above, the same elements are denoted by the same reference numerals and a part of the description is omitted.

In FIG. 3, reference numeral 20 denotes a liquid crystal display device as a third embodiment. The liquid crystal display device 20 includes a liquid crystal display panel 21 including an FLC dot matrix display unit 12 and a segment ferroelectric liquid crystal display unit 23 having a ferroelectric liquid crystal layer (hereinafter abbreviated as FLC segment display unit 23). FLC dot matrix driver IC 14 for supplying a driving signal for driving the ferroelectric liquid crystal layer to the FLC dot matrix display unit 12 and signal electrode driving for supplying a driving signal for driving the ferroelectric liquid crystal layer to the FLC segment display unit 23 It is composed of a ferroelectric liquid crystal driver built-in microcomputer 26 (hereinafter abbreviated as FLC driver built-in microcomputer 26) that incorporates a ferroelectric liquid crystal driver circuit 25 (hereinafter abbreviated as FLC segment driver circuit 25).

  Here, like the liquid crystal display panel 120 shown in the conventional example (see FIG. 9B), the liquid crystal display panel 21 has a pair of opposing glass substrates that sandwich the liquid crystal layer. A dot matrix display unit 12 and an FLC segment display unit 23 are formed. Since the FLC dot matrix driver IC 14 is mounted on the glass substrate of the liquid crystal display panel 21, the FLC dot matrix display unit 12, the FLC segment display unit 23, and the FLC dot matrix driver IC 14 are used as one liquid crystal display panel 21. It is integrated.

  The FLC dot matrix display unit 12 is the same as the FLC dot matrix display unit 12 of the second embodiment, and includes a large number of scanning electrodes and signal electrodes. The FLC segment display unit 23 is the same as the TN segment display unit of the previous embodiment except that the liquid crystal layer is a ferroelectric liquid crystal layer, and includes a relatively small number of scanning electrodes and signal electrodes. Details of the electrode structure and the like of these display portions will be described later.

  The microcomputer 26 with built-in FLC driver has a built-in CPU, ROM, RAM, input port, output port, clock circuit (timer circuit) and the like (not shown) in addition to the built-in FLC segment driver circuit 25, and a control signal P1 from the outside. The FLC segment driver circuit 25 is input, and the dot display control signal P2 is output from an output port (not shown) and supplied to the FLC dot matrix driver IC 14.

  A plurality of scanning signals FCM and a plurality of display signals FSG are output as drive signals from the FLC segment driver circuit 25 built in the microcomputer 26 with built-in FLC driver, and supplied to the aforementioned FLC segment display unit 23. The FLC dot matrix driver IC 14 receives the dot display control signal P2 from the microcomputer 26 with built-in FLC driver, outputs a plurality of scanning signals FMCM and the display signal FMSG as drive signals, and supplies them to the FLC dot matrix display unit 12 described above. To do.

  Further, the microcomputer 26 with built-in FLC driver and the FLC dot matrix driver IC 14 are driven by inputting the power supply VDD from the outside as in the second embodiment. The microcomputer 26 with built-in FLC driver operates by being supplied with the power supply VDD, and controls the dot matrix driver IC 14 in a separate chip from the built-in FLC segment driver circuit 25 based on the control signal P1, and the FLC segment display unit 23 Various information is displayed on the FLC dot matrix display unit 12.

  As described above, in the liquid crystal display device 20 of the present embodiment, the FLC dot matrix display unit 12 with a large number of drive signals is driven by the FLC dot matrix driver IC 14, and the FLC segment display unit 23 with a small number of drive signals is replaced with a microcomputer with built-in FLC driver. The liquid crystal panel with a large amount of display information can be controlled by a single microcomputer and can be displayed with a large amount of information by being driven by the built-in FLC segment driver circuit 25.

Similarly to the second embodiment, the liquid crystal display panel 21 includes the FLC dot matrix display unit 12 and the FLC segment display unit 23 formed on the glass substrate, and the FLC dot matrix driver IC 14 is also mounted on the glass substrate and integrated. Therefore, a small and thin liquid crystal display device can be realized, and a number of signal lines of the scanning signal FMCM and the display signal FMSG for electrically connecting the FLC dot matrix driver IC 14 and the FLC dot matrix display unit 12 are formed on the glass substrate. Can be formed.

  Further, since both the FLC dot matrix display unit 12 and the FLC segment display unit 23 have memory characteristics, the scanning signal FMCM and the display signal FMSG, and the scanning signal FCM and the display signal FSG are only displayed when the display is rewritten. When the display is not rewritten, the FLC dot matrix driver IC 14 and the FLC segment driver circuit 25 are put into a pause state to stop the output of the scanning signal FMCM, the display signal FMSG, and the scanning signal FCM and the display signal FSG. I can do it. As a result, the current consumption of the FLC dot matrix driver IC 14 and the FLC dot matrix display unit 12, and the FLC segment driver circuit 25 and the FLC segment display unit 23 can be made extremely small, so that a liquid crystal display device with a low current consumption can be realized.

  In addition, since the liquid crystal display device 20 of the present embodiment includes a liquid crystal display panel having memory properties for both of the two display portions, the power supply VDD is supplied during the period from rewriting each display portion to the next display rewriting. The FLC driver built-in microcomputer 26 and the FLC dot matrix driver IC 14 may be completely stopped. As a result, even when the power is off, the two display units display information, but the current consumption as the liquid crystal display device can be made close to zero. Also, only the timer circuit (not shown) of the microcomputer 26 with built-in FLC driver is operated, and the microcomputer 26 with built-in FLC driver is started by interruption every predetermined time from the timer circuit, and the display writing operation is executed. May be.

  In addition, since the FLC segment display unit 23 may be time-division driven at most about 1/4 considering the number of pixels, the display flickering phenomenon caused by the reset operation described later is small when rewriting the display. is there. For this reason, information that is frequently rewritten, such as time display, is performed by the FLC segment display unit 23 so that the flicker phenomenon is not noticeable even if the display is frequently rewritten, and information that is not frequently rewritten is FLC with a large number of divisions. The dot matrix display unit 12 can be used, and even if flickering is visible, the frequency of rewriting is low, so that an inconspicuous configuration can be employed. In this way, by selecting the display contents of the two display units of the FLC segment display unit 23 and the FLC dot matrix display unit 12 in consideration of the rewrite frequency, a liquid crystal display device with better display quality can be realized.

  Further, the microcomputer 26 with built-in FLC driver used in the present embodiment must be a microcomputer having a driver circuit capable of driving a ferroelectric liquid crystal, but the microcomputer capable of driving the ferroelectric liquid crystal is already being commercialized. It seems that the general-purpose type microcomputer with built-in FLC driver can be obtained sufficiently. Therefore, also in this embodiment, by using a general-purpose FLC driver built-in microcomputer together with a general-purpose driver IC for ferroelectric liquid crystal, various excellent effects can be obtained as in the first and second embodiments. .

[Description of drive electrode of dot matrix display section: FIG. 4]
Next, a configuration example of the drive electrode of the dot matrix display portion of each embodiment will be described with reference to FIG. Note that, as a premise of the description, the internal structure of the dot matrix display unit is the same as that of FIG. 9B shown in the conventional example, and therefore detailed description thereof is omitted, and only the configuration of the electrodes will be described. In FIG. 4, the dot matrix display unit 2a includes scanning electrodes COM1 to COM7 and signal electrodes SEG1 to SEG7, which are transparent drive electrodes, arranged in rows and columns, and the overlapping portion of each electrode is a pixel G. Formed. Although not shown, a TN liquid crystal layer or a ferroelectric liquid crystal layer is formed between the scan electrodes COM1 to COM7 and the signal electrodes SEG1 to SEG7.

  For the purpose of description to be described later, the pixel G1 is a pixel formed by the scan electrode COM1 and the signal electrode SEG1, the pixel G2 is a pixel formed by the scan electrode COM2 and the signal electrode SEG1, the pixel G3 is a pixel formed by the scan electrode COM3 and the signal electrode SEG1. A pixel formed by COM4 and the signal electrode SEG1 is defined as a pixel G4, and is referred to as a pixel G when an unspecified pixel is indicated.

  The number of scan electrodes COM and signal electrodes SEG is shown as seven for convenience of explanation. However, the number is not limited to this, and actually, as an example, there are 128 scan electrodes COM and 160 signal electrodes SEG. It is. The segment display unit has the same basic configuration except that the number of drive electrodes and the electrode shape are different. For example, in the case of static drive, the number of signal electrodes SEG is the same as the number of pixels, and the scan electrodes COM can be a single solid electrode.

[Description of Drive Signal: FIG. 5]
Next, an example of a drive signal for rewriting the dot matrix display portion 2a will be described with reference to FIGS. As the drive signal, a general drive method for driving a liquid crystal panel using TN liquid crystal or ferroelectric liquid crystal can be employed. Here, as an example, the drive signal of the FLC dot matrix display unit using ferroelectric liquid crystal will be described in detail. The FLC dot matrix display unit 12 shown in the previous embodiment has a number of scan electrodes and signal electrodes as described above, but here, for convenience of explanation, 4 supplied to the four scan electrodes COM1 to COM4. One scanning signal FMSG1 supplied to one scanning electrode FMCM1 to FMCM4 and one signal electrode SEG1 is illustrated, and driving signals applied to the pixels G1, G2, G3, and G4 will be described. Further, the combined drive signals FMCM1-FMSG1 applied to the pixel G1 and the combined drive signals FMCM4-FMSG1 applied to the pixel G4 will be described with reference to the drawings.

  Each drive signal is output as a four-value voltage, that is, voltage V0, voltage V1, voltage V2, and voltage V3. Here, the voltage V3 is set to a voltage value equal to or higher than the saturation voltage Vh of the ferroelectric liquid crystal shown in FIG. 10, and the voltage V1 is set to a voltage value equal to or lower than the threshold voltage Vt. As an example, voltage V3 = 5 volts, voltage V2 = 2/3 × voltage V3, voltage V1 = 1/3 × voltage V3, and voltage V0 = 0 volts. Therefore, the voltage differences among the voltages V0, V1, V2, and V3 are equal to each other and become the value of the voltage V1.

  In FIG. 5, the drive signal includes a reset period Rs for resetting the ferroelectric liquid crystal layers of all the pixels G (see FIG. 4) to one stable state in order to rewrite the display, and display data for each pixel G. A selection period Sct for writing. The selection period Sct includes a period S1 for selecting the scan electrode COM1, a period S2 for selecting the scan electrode COM2, a period S3 for selecting the scan electrode COM3, and a period S4 for selecting the scan electrode COM4. When the number of scan electrodes is n, the selection period Sct is from the period S1 to the period Sn although not shown.

  First, the reset period Rs will be described. As described above, the reset period Rs is a period for resetting the ferroelectric liquid crystal layer of the FLC dot matrix display unit 12 to one stable state. All of the scanning signals FMCM1 to FMCM4 output a pulse of the voltage V3 in the first half of the reset period Rs and output the voltage V0 in the second half of the reset period Rs. Further, the display signal FMSG1 outputs the voltage V0 in the first half of the reset period Rs and outputs a pulse of the voltage V3 in the second half of the reset period Rs. When the number of scan electrodes is n, all of the scan signals FMCM1 to FMMCn output a pulse of the voltage V3 in the first half of the reset period Rs, and when the number of signal electrodes is n, the display signals FMSG1 to FMSGn All output a pulse of voltage V3 in the second half of the reset period Rs.

As a result, for example, the combined drive signals FMCM1-FMSG1 applied to the ferroelectric liquid crystal layer of the pixel G1 (see FIG. 4) formed by overlapping the scan electrode COM1 and the signal electrode SEG1 are reset period Rs as shown in the figure. In the first half, voltage + V3 is applied, and in the second half of the reset period Rs, voltage -V3 is applied. That is, in the reset period Rs, a bipolar reset pulse having a voltage ± V3 is applied to the pixel G1.

  Similarly, the composite drive signal FMCM4-FMSG1 applied to the ferroelectric liquid crystal layer of the pixel G4 (see FIG. 4) formed by overlapping the scan electrode COM4 and the signal electrode SEG1 is a bipolar reset of the voltage ± V3. A pulse is applied. As described above, the voltage + V3 is applied in the first half of the reset period and the voltage -V3 is applied in the second half, so that all the pixels G of the FLC dot matrix display unit 12 first apply the voltage + V3 to the second stable state. The state (white display: refer to FIG. 10) is entered, and the first stable state (black display: refer to FIG. 10) is instantaneously reset upon application of the next voltage -V3.

  That is, all the pixels G are rewritten to black display by the reset pulse applied in the reset period Rs. It is also possible to reset to the second stable state (white display) by inverting the reset pulse.

  Next, when the reset period Rs ends, the drive signal shifts to the selection period Sct described above. Here, since the period S1 is a selection period of the scan electrode COM1, the scan signal FMCM1 applied to the scan electrode COM1 is output with the voltage V0 in the first half of the period S1 and the voltage V3 in the second half of the period S1, as shown in the figure. Is output. The waveforms of the voltages V0 and V3 in the period S1 are selection waveforms for selecting the scan electrode COM1. Further, during the other period of the scanning signal FMCM1, that is, the periods S2 to S4, as shown in the figure, the voltage V2 is output in the first half of each period and the voltage V1 is output in the second half of each period.

  Further, since the period S2 is a selection period of the scan electrode COM2, the scan signal FMCM2 applied to the scan electrode COM2 is output with the voltage V0 in the first half of the period S2 and the voltage V3 in the second half of the period S2, as shown in the figure. Is output. The waveforms of the voltages V0 and V3 in this period S2 are selection waveforms for selecting the scan electrode COM2. Further, in the other period of the scanning signal FMCM2, that is, the periods S1, S3, and S4, as shown in the figure, the voltage V2 is output in the first half of each period and the voltage V1 is output in the second half of the period. The

  Further, since the period S3 is a selection period of the scan electrode COM3, the scan signal FMCM3 applied to the scan electrode COM3 is output with the voltage V0 in the first half of the period S3 and the voltage V3 in the second half of the period S2, as shown in the figure. Is output. The waveforms of the voltages V0 and V3 in the period S3 are selection waveforms for selecting the scan electrode COM3. Further, during the other period of the scanning signal FMCM3, that is, the periods S1, S2, and S4, as shown in the figure, the voltage V2 is output in the first half of each period and the voltage V1 is output in the second half of the period. The

  Further, since the period S4 is a selection period of the scan electrode COM4, the scan signal FMCM4 applied to the scan electrode COM4 is output with the voltage V0 in the first half of the period S4 and the voltage V3 in the second half of the period S2, as shown in the figure. Is output. The waveforms of the voltages V0 and V3 in the period S4 are selection waveforms for selecting the scan electrode COM4. Further, during the other period of the scanning signal FMCM4, that is, the periods S1 to S3, as shown in the figure, the voltage V2 is output in the first half of each period and the voltage V1 is output in the second half of the period.

Next, the display signal FMSG1 in the selection period Sct will be described. As an example of rewriting the pixel, a case will be described in which the pixels G1 and G4 are rewritten from black display in the reset state to white display, and the pixels G2 and G3 are continued in the reset state black display. Here, when the pixels G1 and G4 are rewritten to white display, the pixel G1 has a period S during which the scan electrode COM1 is selected.
Since the display signal FMSG1 is selected by 1, the voltage V3 is output in the first half of the period S1, and the voltage V0 is output in the second half of the period S1, as shown in the figure. Further, since the pixel G4 is selected by the period S4 for selecting the scan electrode COM4, the display signal FMSG1 outputs the voltage V3 in the first half of the period S4 and the voltage V0 in the second half of the period S4 as shown in the figure. .

  Further, since the pixel G2 that is not rewritten is selected in the period S2 for selecting the scan electrode COM2, the display signal FMSG1 outputs the voltage V1 in the first half of the period S2, as shown in the figure, and in the second half of the period S2. The voltage V2 is output. Similarly, the pixel G3 that is not rewritten is selected in the period S3 during which the scan electrode COM3 is selected. Therefore, the display signal FMSG1 outputs the voltage V1 in the first half of the period S3 as shown in FIG. The voltage V2 is output in the second half.

  Next, a waveform of the combined drive signal FMCM1-FMSG1 applied to the pixel G1 in the selection period Sct will be described. First, in the period S1, in the first half of the period S1, the voltage V0 of the scanning signal FMCM1 and the voltage V3 of the display signal FMSG1 are combined to become a voltage −V3 as illustrated. In the second half of the period S1, the voltage V3 of the scanning signal FMCM1 and the voltage V0 of the display signal FMSG1 are combined to become a voltage + V3 as shown in the figure. Thereby, the pixel G1 is rewritten from black display to white display in the period S1.

  In the first half of the other periods S2 and S3 of the combined drive signal FMCM1-FMSG1, the voltage V2 of the scanning signal FMCM1 and the voltage V1 of the display signal FMSG1 are combined to become the voltage + V1 as shown. In the second half of the periods S2 and S3, the voltage V1 of the scanning signal FMCM1 and the voltage V2 of the display signal FMSG1 are combined to become a voltage −V1 as shown in the figure.

  Similarly, in the first half of the other period S4 of the combined drive signals FMCM1-FMSG1, the voltage V2 of the scanning signal FMCM1 and the voltage V3 of the display signal FMSG1 are combined to become a voltage -V1 as shown. In the second half of the period S4, the voltage V1 of the scanning signal FMCM1 and the voltage V0 of the display signal FMSG1 are combined to become a voltage + V1 as illustrated. Therefore, the voltage ± V1 is applied during the period S2 to S4 of the pixel G1, and the voltage ± V1 is lower than the threshold voltage Vt of the ferroelectric liquid crystal as described above. Continues to display white without being rewritten.

  Next, the waveform in the selection period Sct of the composite drive signal FMCM4-FMSG1 applied to the pixel G4 will be described. Here, in the first half of the period S1 of the combined drive signals FMCM4-FMSG1, the voltage V2 of the scanning signal FMCM4 and the voltage V3 of the display signal FMSG1 are combined to become a voltage -V1 as shown. Further, in the second half of the period S1, the voltage V1 of the scanning signal FMCM4 and the voltage V0 of the display signal FMSG1 are combined to become a voltage + V1 as illustrated.

  Similarly, in the first half of the periods S2 and S3 of the combined drive signal FMCM4-FMSG1, the voltage V2 of the scanning signal FMCM4 and the voltage V1 of the display signal FMSG1 are combined to become the voltage + V1 as illustrated. In the second half of the periods S2 and S3, the voltage V1 of the scanning signal FMCM4 and the voltage V2 of the display signal FMSG1 are combined to become a voltage −V1 as illustrated. Accordingly, the voltage ± V1 is applied during the periods S1 to S3 of the pixel G4, and the voltage ± V1 is lower than the threshold voltage Vt of the ferroelectric liquid crystal as described above. Continues black display without being rewritten from the reset state.

In the first half of the period S4 of the combined drive signal FMCM4-FMSG1, the voltage V0 of the scanning signal FMCM4 and the voltage V3 of the display signal FMSG1 are combined to become a voltage -V3 as shown. Further, in the latter half of the period S4, the voltage V3 of the scanning signal FMCM4 and the voltage V0 of the display signal FMSG1 are combined to become a voltage + V3 as shown in the figure. Thereby, the pixel G4 is rewritten from the black display in the reset state to the white display in this period S4.

  As described above, each pixel G of the FLC dot matrix display unit 12 applies the voltage V3 in the first half of the selection period and the voltage in the second half in accordance with the timing of the scanning signal in which the pixel is selected. By applying V0, the black display in the reset state can be rewritten to white display.

  After the display is rewritten, the FLC dot matrix display unit 12 has a memory property, so that the scanning signal and the display signal may be fixed at the voltage V0. That is, the drive waveform shown in FIG. 5 may be supplied when the FLC dot matrix display unit 12 is rewritten, and when it is not necessary to rewrite, all the drive signals may be fixed at the voltage V0, for example. As a result, a liquid crystal display device that consumes very little current can be realized.

  In FIG. 5, only the combined drive signals FMCM1-FMSG1 applied to the pixel G1 and the combined drive signals FMCM4-FMSG1 applied to the pixel G4 have been illustrated and described, but the pixel G2 selected in the period S2 The combined drive signal applied to the pixel G3 selected in the period S3 is such that the waveform of the display signal FMSG1 is both the voltage V1 in the first half of the period and the voltage V2 in the second half of the period. V1 and the pixels G2 and G3 are not rewritten.

  That is, the scanning signals FMCM1 to FMCM4 and the display signal FMSG1 illustrated in FIG. 5 rewrite the pixels G1 and G4 in the dot matrix display section shown in FIG. 4 to white display and maintain the pixels G2 and G3 in black display in the reset state. It is an example of the drive waveform to perform. The driving waveform of the FLC dot matrix display unit 12 is not limited to that shown in FIG. 5 and may be arbitrarily changed according to the characteristics of the ferroelectric liquid crystal.

  In addition, as described above, the driving of the ferroelectric liquid crystal generally rewrites the display after resetting the entire screen, so a predetermined time is required until the screen is rewritten after entering the reset state. If the number of scanning electrodes is large, the time until rewriting becomes long, and a flicker phenomenon may be seen on the display screen when rewriting the display. This flicker phenomenon is a noticeable phenomenon when the number of scan electrodes is large and the rewrite frequency is high. Here, as described above, the liquid crystal display device of the third embodiment includes two display units, the FLC segment display unit 23 with a small number of scanning electrodes and the FLC dot matrix display unit 12 with a large number of scanning electrodes. Therefore, the display information with a low rewrite frequency is displayed on the FLC dot matrix display unit 12, and the display information with a high rewrite frequency is displayed on the FLC segment display unit 23, whereby the flicker phenomenon can be reduced. .

  The driving waveform of the FLC segment display unit 23 may be the same as the driving waveform shown in FIG. Further, since the driving waveform of the TN liquid crystal used in the first and second embodiments is known, the description thereof is omitted here.

[Description of arrangement configuration: FIG. 6]
Next, an example of an optimal arrangement configuration of the segment display unit, the dot matrix display unit, and the dot matrix driver IC in the liquid crystal display device of the present invention will be described with reference to FIG. It should be noted that either a liquid crystal display panel using TN liquid crystal or a liquid crystal display panel using ferroelectric liquid crystal can be used. Here, both the segment display unit and the dot matrix display unit are used. The case of using ferroelectric liquid crystal is described below. The same elements as those in the block diagrams of the above-described embodiments are denoted by the same reference numerals, and a part of overlapping description is omitted. In FIG. 6, the configuration of the liquid crystal display device 20 is roughly divided into a liquid crystal display panel 21, a circuit board 30 on which the microcomputer 26 with built-in FLC driver is mounted, and a connection member that connects the liquid crystal display panel 21 and the circuit board 30. It is constituted by a flexible substrate 40 (hereinafter abbreviated as FPC 40).

  Similarly to the liquid crystal display panel 120 (see FIG. 9) shown in the conventional example, the liquid crystal display panel 21 has a pair of glass substrates 22, and the FLC segment display unit 23 and the FLC dot matrix are provided on the glass substrate 22. The display unit 12 is formed, and the FLC dot matrix driver IC 14 is mounted on the surface of the glass substrate 22 by a flip chip mounting method or the like. In addition, a connecting portion 22a for connecting the FPC 40 is provided on the lower side of the glass substrate 22 in the drawing. The connecting portion 22a is formed of a plurality of transparent electrodes made of an ITO (Indium Tin Oxide) film.

  Here, the electrical connection between the elements on the liquid crystal display panel 21 will be described. Since the electrical connection between these elements is as shown in the block diagram shown in FIG. 3 described above, the overlapping description is omitted, but the connection unit 22a and the FLC dot matrix driver IC 14 have a plurality of dot displays. A control signal P2 is connected. The FLC dot matrix driver IC 14 and the FLC dot matrix display unit 12 are connected to a large number of scanning signals FMCM and display signals FMSG. Further, the scanning signal FCM and the display signal FSG are connected to the connection unit 22a and the FLC segment display unit 23. Each signal line on the drawing is schematically shown and does not indicate the actual number of wirings. The power supply VDD and the like are not shown. Each signal line is formed of an ITO film on the surface of the glass substrate 22.

  Next, the arrangement of each element on the liquid crystal display panel 21 will be described. Here, the FLC dot matrix driver IC 14 is disposed near the connection portion 22a located at the lower end of the glass substrate 22, and the FLC dot matrix display portion 12 is formed near the FLC dot matrix driver IC 14 to connect the connection portion. The FLC segment display unit 23 is arranged at a position far from 22a. That is, the connecting portion 22a is arranged at the lower end of the glass substrate 22 in the drawing of FIG. 6, and from this connecting portion 22a, the FLC dot matrix driver IC 14, the FLC dot matrix display portion 12, and the FLC segment display are displayed. The parts 23 are preferably arranged in the order.

  Although not shown, when the connecting portion 22a is disposed at the upper end of the glass substrate 22, the connecting portion 22a, the FLC dot matrix driver IC 14 and the FLC dot matrix display portion 12 are viewed from above the glass substrate 22. The FLC segment display unit 23 is preferably arranged in this order.

  The above-described arrangement of the elements of the liquid crystal display panel 21 provides many advantages. For example, as described above, the FLC dot matrix display unit 12 preferably has a large number of pixels for displaying various information. For example, the FLC dot matrix display unit 12 has a pixel of 128 dots × 160 dots. The matrix driver IC 14 outputs 128 scanning signals FMCM and 160 display signals FMSG, that is, a total of 288 drive signals, and is connected to the FLC dot matrix display unit 12. As described above, the number of drive signal lines of the FLC dot matrix display unit 12 is enormous. However, since the FLC dot matrix display unit 12 and the FLC dot matrix driver IC 14 are arranged close to each other as shown in the drawing, a large number of drive signals are provided. Lines can be connected with the shortest route.

  Thereby, since the area of the drive signal wiring area on the glass substrate 22 can be reduced, the useless area of the glass substrate 22 can be eliminated and the external size of the liquid crystal display panel 21 can be reduced. Further, since the length of the drive signal line is short, the wiring resistance of the ITO film forming the drive signal line can be minimized, the driving waveform is prevented from being dull, and each pixel of the FLC dot matrix display unit 12 is reliably driven. I can do it.

  Further, as shown in the figure, the FLC segment display unit 23 and the connection unit 22a are arranged at a distance from each other because the FLC dot matrix display unit 12 and the FLC dot matrix driver IC 14 are located between them. The number of signal lines of the scanning signal FCM and the display signal FSG, which are drive signals for connecting the connection portion 22a, and the number of signal lines of the scanning signal FMCM and the display signal FMSG for connecting the FLC dot matrix driver IC 14 and the FLC dot matrix display portion 12 are as follows. The number is considerably smaller than that.

  For example, when the FLC segment display unit 23 is a four-part matrix drive and the number of pixels is 44, there are four scanning signals FCM and 11 display signals FSG, which is a total of 15. Therefore, even if the positions of the FLC segment display portion 23 and the connection portion 22a are separated from each other, the number of wirings is small, so that the signal line width formed of the ITO film can be increased. For this reason, even if the wiring distance is long, the wiring resistance can be reduced, the driving waveform is prevented from being dull, and each pixel of the FLC segment display unit 23 can be driven reliably.

  Further, since the connecting portion 22a and the FLC dot matrix driver IC 14 are arranged at close positions, the wiring distance of the dot display control signal P2 connecting the connecting portion 22a and the FLC dot matrix driver IC 14 can be shortened. High-speed control signals can be transmitted with high quality with low resistance wiring.

  Further, since the connecting portion 22a for connecting the FPC 40 is connected only to the scanning signal FCM, the display signal FSG, the dot display control signal P2, and the power source (not shown), the number of connections is small, and the number of wirings of the FPC 40 is small. Therefore, each wiring width of the FPC 40 can be designed to be thick, and the outer width of the FPC 40 can be made relatively narrow. As a result, the wiring resistance of the FPC 40 can be lowered and the handling becomes easy. In addition, the small number of FPCs 40 connected increases the reliability of the connection between the FPC 40 and the connection part 22a of the glass substrate 22 and the connection between the FPC 40 and the circuit board 30 and the workability of the fixing work for connection. It is very effective. The wiring of the FPC 40 is not shown.

  Next, the circuit board 30 will be described. On the circuit board 30, a microcomputer 26 with a built-in FLC driver and a connector 31 are mounted. The circuit board 30 is connected to the aforementioned FPC 40, and the circuit board 30 and the liquid crystal display panel 21 are electrically and mechanically connected by the FPC 40. The connection between the circuit board 30 and the FPC 40 may be directly fixed by solder or the like, or may be connected via a surface mount connector (not shown). Further, the FLC driver built-in microcomputer 26 outputs signal lines such as a dot display control signal P2, a scanning signal FCM, and a display signal FSG, and is electrically connected to the FPC 40.

  By this wiring, the dot display control signal P2, the scanning signal FCM, and the display signal FSG from the microcomputer 26 with built-in FLC driver are transmitted to the liquid crystal display panel 21 via the FPC 40. The connector 31 is installed for inputting a control signal P1 and a power source (not shown) from a main body (not shown) in which the liquid crystal display device 20 is incorporated, and a control including display information is performed via the connector 31. The signal P1 is input and transmitted to the FLC driver built-in microcomputer 26. Note that the wiring of the circuit board 30 is schematically shown, and does not indicate the actual number of wirings. Further, the circuit board 30 is mounted with only the microcomputer 26 with built-in FLC driver and the connector 31, but is not limited to this, and other electronic components such as a memory and a battery may be arbitrarily mounted.

6 shows the case where the liquid crystal display panel using the ferroelectric liquid crystal is used for the dot matrix display section and the segment display section, that is, the third embodiment is taken as an example. The arrangement is not limited to the third embodiment, and this arrangement example is also applied to the first and second embodiments. That is, in the first embodiment, the liquid crystal display panels 2 and 3 are separated, but are combined as one liquid crystal display panel, and the dot matrix display unit 2a, the segment display unit 3a, and the dot matrix drive IC 4 are combined. The arrangement can be the same as in FIG. Also in the second embodiment, the FLC dot matrix display unit 12, the TN segment display unit 13, and the FLC dot matrix drive IC 14 can be arranged in the same manner as in FIG.

[Description of display example: FIG. 7]
Next, a display example by the liquid crystal display panel of each embodiment will be described with reference to FIG. Here, as a premise for explanation, the arrangement diagram of FIG. 6 is adopted, and the liquid crystal display device of the present invention is incorporated in a device as a display panel of an electronic shelf label for displaying product prices and the like as an example. .

  In FIG. 7, the liquid crystal display panel 31 of the liquid crystal display device of the present embodiment has a segment display unit 3a having a six-segment seven-segment display at the top of the drawing, and a dot matrix display at the bottom of the drawing. A dot matrix display portion 2a is arranged. Here, as described above, when this liquid crystal display device is used as an electronic shelf label, the 6-digit display of the segment display unit 3a displays the time, and here, as an example, 10:08:59 is shown.

  Further, the dot matrix display unit 2a has, for example, pixels of 128 dots × 160 dots, and arbitrarily displays a name, a price, a place of production, a barcode, a figure, etc. for explaining a product as shown in the figure. I can do it.

  Here, in the case of an electronic shelf label, the display content of the dot matrix display unit 2a for explaining the product may be determined and displayed before the opening of the day, such as the type and price of the product. It is more convenient to adopt an FLC dot matrix display unit using a ferroelectric liquid crystal layer having a property. That is, the microcomputer 26 with built-in FLC driver (see FIG. 3) operates before the opening of the day, controls the FLC dot matrix driver IC 14 (see FIG. 3), rewrites the display content of the dot matrix display unit 2a, The dot matrix display unit 2a continues the rewritten display information by putting the FLC dot matrix driver IC 14 in a dormant state or turning off the power supply and setting the drive signal to the dot matrix display unit 2a to 0 volts. In addition, the current consumption for displaying the dot matrix display portion 2a can be made substantially zero.

  In addition, even when displaying the time on the segment display unit 3a, if the FLC segment display unit using a ferroelectric liquid crystal layer having a memory property, after rewriting the display content, until the next display is updated, Since the drive signal can be fixed at 0 volts, the current consumption for displaying the segment display unit 3a can be extremely reduced.

  Further, the segment display unit for displaying the time may be the TN segment display unit 13 having a general TN liquid crystal layer as in the second embodiment. That is, in the case of the time display including the second display, the display content needs to be rewritten every second, so that there is little need for a segment display unit having a memory property.

  Further, both the segment display unit 3a and the dot matrix display unit 2a may be a liquid crystal display panel using a TN liquid crystal layer as in the first embodiment. In this case, the liquid crystal display panel needs to be driven at all times. However, since it can be manufactured by a general TN liquid crystal, it is excellent in mass productivity and the cost can be reduced.

Although FIG. 7 shows an electronic shelf label as an example, the liquid crystal display device of the present invention is not limited to the electronic shelf label, and can be applied to display devices of various electronic devices. For example, in the case of a liquid crystal display device incorporated in a multi-function type watch, the segment display unit 3a displays time, and the FLC dot matrix display unit 12 displays one month calendar. Can be rewritten once a day or once a month, and is suitable as a liquid crystal display device having a memory property.

  Further, the block diagram and the layout diagram shown in the embodiment of the present invention are not limited to this, and may be arbitrarily changed as long as they satisfy the gist of the present invention.

  Since the liquid crystal display device of the present invention has a simple configuration and low current consumption, it is particularly suitable as a display device for battery-driven small electronic devices, and displays such as electronic shelf labels, electronic watches, mobile phones, and portable terminals. It can be used as a device.

DESCRIPTION OF SYMBOLS 1, 10, 20 Liquid crystal display device 2, 3, 11, 21, 31 Liquid crystal display panel 2a Dot matrix display part 3a Segment display part 4 Dot matrix electrode drive liquid crystal driver IC (dot matrix driver IC)
5 Signal electrode drive LCD driver circuit (segment driver circuit)
6, 16 Microcomputer (microcomputer)
12 Ferroelectric liquid crystal dot matrix display (FLC dot matrix display)
13 TN segment display unit 14 Dot matrix electrode driving ferroelectric liquid crystal driver IC (FLC dot matrix driver IC)
15 TN liquid crystal driver circuit for signal electrode drive (TN segment driver circuit)
22 Glass substrate 22a Connection part 23 Segment ferroelectric liquid crystal display part (FLC segment display part)
25 Signal electrode drive ferroelectric liquid crystal driver circuit (FLC segment driver circuit)
26 Microcomputer with built-in ferroelectric liquid crystal driver (microcomputer with built-in FLC driver)
30 Circuit Board 31 Connector 40 Flexible Board (FPC)
G, G1 to G4 Pixels COM1 to COM7 Scan electrode SEG1 to SEG7 Signal electrode P1 Control signal P2 Dot display control signal CM, MCM, FCM, FMCM Scan signal SG, MSG, FSG, FMSG Display signal VDD Power supply

Claims (8)

A liquid crystal display panel having a segment display section and a dot matrix display section;
A microcomputer incorporating a signal electrode driving liquid crystal driver circuit for supplying a driving signal to the segment display unit;
A liquid crystal driver IC for driving a dot matrix electrode for supplying a drive signal to the dot matrix display unit based on a control signal of the microcomputer;
A liquid crystal display device comprising:   2. The dot matrix display unit includes a ferroelectric liquid crystal layer, and the dot matrix electrode driving liquid crystal driver IC outputs a drive signal for driving the ferroelectric liquid crystal layer. A liquid crystal display device according to 1.   3. The segment display unit includes a ferroelectric liquid crystal layer, and the signal electrode driving liquid crystal driver circuit outputs a driving signal for driving the ferroelectric liquid crystal layer. A liquid crystal display device according to 1.   4. The liquid crystal display device according to claim 1, wherein the segment display unit and the dot matrix display unit are integrated to form a single liquid crystal display panel. 5.   5. The liquid crystal display device according to claim 1, wherein the dot matrix electrode driving liquid crystal driver IC is mounted on a substrate of the liquid crystal display panel. The liquid crystal display panel has a connection part for inputting the drive signal from the outside,
The liquid crystal display device according to claim 1, wherein the connection portion and the microcomputer are electrically connected by a connection member. In the liquid crystal display panel, the dot matrix electrode driving liquid crystal driver IC is disposed near the connection portion,
7. The liquid crystal display according to claim 6, wherein the dot matrix display section is formed at a position close to the dot matrix electrode driving liquid crystal driver IC, and the segment display section is formed at a position far from the connection section. apparatus. The liquid crystal display device according to claim 6, wherein the connection member is a flexible substrate.

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