JP2002149124A - Ferroelectric liquid crystal module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device equipped with a ferroelectric liquid crystal panel with which the space required for the module can be reduced and image display can be performed without electric power. SOLUTION: A power source circuit for supplying the electric signal for rewriting the display of the ferroelectric liquid crystal panel is not incorporated into the main body of the module into which the liquid crystal panel is installed, but the electric signal for display rewriting is transmitted from a signal generating device separated from the main body.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus provided with a liquid crystal display panel using a ferroelectric liquid crystal as a liquid crystal layer.

[0002]

2. Description of the Related Art In general, it is known that ferroelectric liquid crystal molecules move along the side surface of a cone (hereinafter referred to as a liquid crystal cone) due to an external change such as an electric field. When a ferroelectric liquid crystal is sandwiched between a pair of substrates and used as a liquid crystal panel, the ferroelectric liquid crystal is controlled so as to be located at two positions on the side surface of the liquid crystal cone by the polarity of voltage application. These two stable ferroelectric liquid crystal states are referred to as a first ferroelectric state and a second ferroelectric state.

FIG. 1 is an example of a configuration diagram of a ferroelectric liquid crystal panel when a ferroelectric liquid crystal is used as a display. Between the polarizing plates 11a and 11b whose polarization axis directions are substantially perpendicular to each other (crossed Nicols), the polarization axis of one of the polarizing plates and the first ferroelectric state when no voltage is applied, or the second A liquid crystal cell 12 in which a ferroelectric liquid crystal is sandwiched between a pair of substrates so that the molecular long axis direction of the ferroelectric liquid crystal in a ferroelectric state or one of the ferroelectric states is parallel.
Was placed. In the case of FIG. 1, it is aligned with the long axis direction of the ferroelectric liquid crystal molecules in the second ferroelectric state.

In the installation configuration of the polarizing plate as shown in FIG. 1, if the ferroelectric liquid crystal takes a ferroelectric state in which the direction of the polarization axis of the polarizing plate is made coincident, here, the second ferroelectric state, the light is Does not pass through, and the ferroelectric liquid crystal panel displays black (non-transmission state). Also, depending on the polarity of the applied voltage, the ferroelectric liquid crystal enters a ferroelectric state that is not aligned with the polarization axis of the polarizing plate,
Since the ferroelectric liquid crystal molecules are inclined at a certain angle with respect to the polarization axis, light is transmitted from the backlight, and white display (transmission state) can be achieved. Here, the polarization axis direction of the polarizing plate matches the second ferroelectric state, but the molecular long axis direction of the first ferroelectric state and the polarization axis direction of the polarizing plate can also match. In that case, black display (non-transmission state) can be performed in the first ferroelectric state, and white display (transmission state) can be performed in the second ferroelectric state. Either of the installation configurations can be adopted in the present invention. Hereinafter, a case where the installation configuration is adopted as shown in FIG. 1 will be described.

FIG. 2 shows the relationship between the value of the applied voltage applied to the ferroelectric liquid crystal panel and the transmittance of the ferroelectric liquid crystal panel. As shown in FIG. 2, when a positive voltage of a certain value or more is applied to the ferroelectric liquid crystal, the ferroelectric liquid crystal enters a first ferroelectric state, and when a polarizing plate is installed as shown in FIG. A transmission state is obtained, and when a negative voltage of a certain value or more is applied, a second ferroelectric state is obtained,
It becomes a non-transmission state in which light does not transmit. As can be seen from this figure, the transmittance of the ferroelectric liquid crystal is maintained even when the applied voltage is 0 V. That is, in the display state in which writing is performed once even when no voltage is supplied from outside, no voltage is supplied from outside. In both cases, the display state can be maintained.

FIG. 3 shows a typical method of driving a ferroelectric liquid crystal display using the ferroelectric liquid crystal panel having the polarizing plate structure shown in FIG. A change in the amount of light (transmittance) transmitted through the ferroelectric liquid crystal panel according to the voltage is shown. ON (W) indicates white display in a transmissive state, and OFF (B) indicates black display in a non-transmissive state. A scanning-side electrode and a signal-side electrode are formed on each of the pair of substrates, and ON and OFF are displayed as pixels where the scanning-side electrode and the signal-side electrode intersect as pixels. The voltage applied to the pixels of the ferroelectric liquid crystal panel can be represented by a combined voltage waveform obtained by combining the scanning voltage waveform applied to the scanning electrode and the signal voltage waveform applied to the signal electrode.

The driving waveform shown in FIG. 3 is constituted by one scanning period for executing a display based on one display data.
In one scanning period, a selection period (Se) for selecting a display state based on display data and a non-selection period (NSe) for holding the selected display state are set, and the next display is written. A reset period (R) for resetting the ferroelectric liquid crystal to one ferroelectric state independently of the display state.
s) is set before the start of the selection period. In FIG. 3, a driving method is used in which the first ferroelectric state is set to a white display (transmissive state) in the first half of the reset period, and the second ferroelectric state is set to a black display (non-transmissive state) in the second half of the reset period. ing. As described above, in the driving method of the ferroelectric liquid crystal display, in order to perform a good display, a pulse having a different polarity is applied without depending on the immediately preceding display state, and a reset period for executing both ferroelectric states is set. It is generally done.

[0008]

Conventionally, in an apparatus using a liquid crystal display using a general liquid crystal such as a nematic as a display portion, an electric signal for performing the display is always transmitted when the display is performed. Since the power needs to be supplied to the panel, power consumption always occurs, and the power consumption of the device is increased. In addition, it is necessary to incorporate a power supply circuit and the like for supplying the electric signal into the apparatus main body, so that the apparatus main body is enlarged accordingly.

Therefore, the present invention is to reduce the power consumption of normal display and to reduce the size of the module body by using a ferroelectric liquid crystal panel having a memory property for the display portion of the ferroelectric liquid crystal module. The purpose is.

[0010]

To achieve the above object, the present invention uses the following means.

The ferroelectric liquid crystal module has an information input unit, and display information displayed on the ferroelectric liquid crystal panel is output from a signal generator separate from the ferroelectric liquid crystal module via the information input unit. It is characterized by being input. It is desirable that the ferroelectric liquid crystal panel be provided with a reflector.

This ferroelectric liquid crystal module does not include a power supply circuit necessary for rewriting display information, and connects a signal generator and an information input section by information supply means to display the ferroelectric liquid crystal panel. The power required to rewrite information is supplied to the ferroelectric liquid crystal module via the information supply means or from a power supply circuit provided in the information supply means. Further, the information supply unit has a function detachable from the information input unit, and can be attached when rewriting display information.

Examples of applications of the ferroelectric liquid crystal module include a clock face of a clock, a display panel for decoration, and the like.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention employs a ferroelectric liquid crystal panel having a structure in which a ferroelectric liquid crystal is sandwiched between a pair of substrates and a reflection plate is provided on one of the substrates. By providing the reflection plate on one of the substrates as described above, the display can be visually recognized by external light, and there is no need to provide illumination such as a backlight inside the liquid crystal panel. Necessary display information is written to the ferroelectric liquid crystal panel from an external signal generator via an information supply unit.

The power required to rewrite the display of the ferroelectric liquid crystal panel may be supplied from a power supply circuit of an external signal generator to the ferroelectric liquid crystal module via the information supply means, or may be supplied to the information supply means. When the power supply circuit is provided in itself and the information supply means is mounted on the ferroelectric liquid crystal module,
The information may be supplied directly from the information supply means. As described above, by providing the power supply circuit in an external device, it is not necessary to provide the power supply circuit in the ferroelectric liquid crystal module itself. Therefore, even after the display information is rewritten, the power consumption of the ferroelectric liquid crystal module can be reduced to zero even if the still image is continuously displayed.

[0016]

(Embodiment 1) An embodiment of the present invention will be described below in detail with reference to the drawings. FIG. 5 is a configuration diagram of a reflection type ferroelectric liquid crystal panel used in the present invention. The ferroelectric liquid crystal panel used in this embodiment includes a pair of glass substrates 53a and 53b having a ferroelectric liquid crystal layer 52 having a thickness of about 1.7 μm. The electrodes 54a and 54b are provided on the opposite surface of the glass substrate.
Was formed, and the polymer alignment films 55a and 55b were applied thereon and rubbed. Further, outside the one glass substrate, the polarization axis of the polarizing plate and the average molecular axis direction of the ferroelectric liquid crystal molecules in the second ferroelectric state when no voltage is applied,
The first polarizing plate 51a is installed so as to be parallel, and the polarization axis of the second polarizing plate 51b is provided outside the other glass substrate.
The second polarizing plate 51b was set so that the direction of the polarizing axis of the first polarizing plate 51a was different from the direction of 90 °. A reflecting plate 56 is provided outside the polarizing plate, and a glass substrate 53 on the viewer side is provided.
The incident light from a is reflected.

FIG. 4 is a diagram showing the configuration when the ferroelectric liquid crystal module is incorporated in a clock face of a watch. The dial portion is a ferroelectric liquid crystal panel 41. Display information desired to be displayed on the ferroelectric liquid crystal panel is input from the information input unit 42. As the display information, a favorite image such as a landscape image or a photograph of a child can be displayed. Since a reflection type panel is used for the ferroelectric liquid crystal panel, no backlight is required, and a power supply circuit necessary for rewriting display information of the ferroelectric liquid crystal panel is not incorporated in the timepiece.

An electric signal serving as display information necessary for rewriting the display was supplied from a signal generator separate from the timepiece body. FIG. 6 shows a diagram in which a signal generator and a timepiece incorporating a ferroelectric liquid crystal module are connected via information supply means. In FIG. 6A, the signal generating device and the information input section 42 of the timepiece incorporating the ferroelectric liquid crystal module are connected as the information supply means 60 with a connection cable. When the display information on the clock face was rewritten, the connection cable was connected, and the display information was input from the signal generator. The power required for rewriting was supplied simultaneously from the signal generation circuit. In addition, the display information of the clock face can be sent to the signal generation circuit.

FIG. 6B shows a diagram in which a signal generator such as an infrared ray or a radio wave as the information supply means 60 and an information input section of the ferroelectric liquid crystal module are connected off-line. In FIG. 6B, an infrared communication device is attached to the information output unit of the signal generator as information supply means 60, and a similar infrared communication device is attached to the information input unit 42 of the watch incorporating the ferroelectric liquid crystal module. I have. When this infrared communication device was used as the information supply means 60 and the display information on the clock face was rewritten, the display information was input from the signal generator. The power required for rewriting was supplied from an infrared communication device which was information supply means 60 attached to the clock.
Also, as in the case where the connection cable is used, the display information of the clock face can be sent to the signal generation circuit. Here, an infrared communication device is used as the information supply unit, but a communication unit using magnetic lines of force, radio waves, or the like other than infrared light may be used.

FIG. 7 is a circuit diagram of the signal generator. The signal generating device includes a display data generating circuit 61, a driving voltage waveform control circuit 62, a scanning-side voltage waveform generating circuit 64, a signal-side voltage waveform generating circuit 63, a power supply circuit 67, and an information output section 65.
It has. When rewriting display information displayed on the ferroelectric liquid crystal module, the scanning-side voltage waveform and the signal-side voltage waveform output from the signal generator are applied to the ferroelectric liquid crystal panel of the ferroelectric liquid crystal module. .

FIG. 3 shows a driving method used as a conventional technique, but can also be used in the present invention. The drive waveform of FIG. 3 is composed of one scanning period for executing display based on one display data, and each scanning period is a selection period (Se) for determining a display state based on display data of a pixel. And a non-selection period (NSe) for maintaining the state determined in the selection period (Se),
Before the start of the scanning period, there is provided a reset period (Rs) for always resetting to an arbitrary state without depending on the display state. When a polarizing plate is installed as shown in FIG. 1 and the relationship between the applied voltage and the light transmittance is as shown in FIG. 2, if the combined voltage applied to the pixels during the reset period is equal to or higher than the positive threshold, the ferroelectric liquid crystal In the first example, the ferroelectric liquid crystal enters the first ferroelectric state, and white display is performed. When the negative threshold is exceeded, the ferroelectric liquid crystal enters the second ferroelectric state, and black display can be performed.

The reset period is composed of six phases. In the first three phases, the scanning-side voltage waveform is set to 20 V, and in the second three phases, -20 V is set. In the ferroelectric state of No. 2, black display was performed. During the selection period of the scanning voltage waveform, 0 V was applied to the first phase, -20 V was applied to the second phase, 20 V was applied to the third phase, and 0 V was applied during the non-selection period.
A voltage of ± 5 V was applied to the signal side voltage waveform. The pulse width of each pulse was set to about 35 μs. As the voltage applied to the pixel, a composite voltage waveform of the scanning-side voltage waveform and the signal-side voltage waveform input from the signal generator is applied, and the state of the ferroelectric liquid crystal molecules in each pixel is determined.

When the display data is ON (white display),
The third phase of the selection period of the composite voltage waveform exceeds the positive threshold value of the ferroelectric liquid crystal and enters the first ferroelectric state. This is maintained during the non-selection period, and white display can be performed. Display data is O
In the case of FF (black display), black display is always performed during the reset period regardless of the previous display state.
A composite voltage equal to or lower than the threshold voltage was applied during the selection period, and black display was maintained during the reset period.

(Embodiment 2) Another embodiment of the present invention will be described below in detail with reference to the drawings. FIG. 8 is a schematic diagram of the present invention. This embodiment is an apparatus in which a ferroelectric liquid crystal module is incorporated in a photo stand as a display panel for decoration. That is, in the past, a photo was placed on a photo stand and displayed, but this device uses a ferroelectric liquid crystal panel instead of the photo and displays the photo to be displayed on a liquid crystal display. In the second embodiment, the same configuration as that of the first embodiment is used, and the polarizing plate is installed as shown in FIG. 1, and the panel configuration is the same as that of the first embodiment shown in FIG.

Also in this embodiment, the connection to the signal generator was performed by inputting and outputting display information using the information supply means as shown in FIG. The same driving method as in Example 1 was used for ON and OFF driving methods required for display.

(Embodiment 3) FIG. 9 is a schematic view of this embodiment. In this embodiment, a ferroelectric liquid crystal module is incorporated in a card-type information device such as a credit card or a commuter pass. In order to write information necessary for display from outside at the time of use, an electric signal required for writing is supplied from the signal input device 42 from the signal generator, and the information is written in the display portion. Also in the present embodiment, the connection with the signal generator was performed by inputting and outputting display information using the information supply means as shown in FIG. The same driving method as in Example 1 was used for ON and OFF driving methods required for display. Once the information was written, the card itself did not have a power supply, but the display could be maintained due to the memory properties of the liquid crystal itself.

FIG. 10 is a configuration diagram of the ferroelectric liquid crystal panel used in this embodiment. The ferroelectric liquid crystal panel of this embodiment was provided with a heater outside the reflection plate. A power supply circuit for the heater was not provided in the device of the ferroelectric liquid crystal module, and a current was supplied from the outside through the information supply means at the time of display rewriting. When the heater is provided inside the liquid crystal panel, the ferroelectric liquid crystal panel can be warmed even at a low temperature, and the display can be rewritten as usual.

(Embodiment 4) FIG. 11 is a schematic view of this embodiment. The present embodiment is an example of a card-type information device having a function of an entrance permit for a visitor. The admission badge incorporates the ferroelectric liquid crystal module of the present invention, and a photograph of a visitor, a nomination, and the like are displayed on a liquid crystal panel. In the present embodiment, the same configuration as that of the first embodiment is adopted for the installation of the polarizing plate as shown in FIG. 1, and the panel configuration is also the same as that of the first embodiment shown in FIG.

Also in this embodiment, the connection with the signal generator is made by using information supply means as shown in FIG.
Input / output of display information. As shown in FIG. 12, the signal generating device employed in this embodiment incorporates a device for photographing, and writes the photograph taken by this device to the ferroelectric liquid crystal panel of the badge body through the information supply means. It is.
The ON and OFF driving methods required for display use the same driving method as in the first embodiment. Since the liquid crystal panel of the ferroelectric liquid crystal module has a memory property, it is not necessary to incorporate a circuit such as a power supply in the badge for permitting entry.

[0030]

The ferroelectric liquid crystal module of the present invention, in which a ferroelectric liquid crystal panel is incorporated, does not incorporate a power supply required for an electric signal for rewriting, so that it is easy to reduce the size of the device. In addition, since the display state can be maintained without applying an electric signal, power for maintaining the display is not required, and the power consumption of the apparatus main body can be reduced.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a ferroelectric liquid crystal panel and a polarizing plate used in the present invention.

FIG. 2 is a transmittance curve diagram of a ferroelectric liquid crystal display used in the present invention.

FIG. 3 is a diagram showing a driving waveform of a ferroelectric liquid crystal display used in the present invention.

FIG. 4 is a conceptual diagram of a timepiece module used in the present invention.

FIG. 5 is a configuration diagram of a ferroelectric liquid crystal panel used in the present invention.

FIG. 6 is a diagram in which the ferroelectric liquid crystal module of the present invention and a signal generator are connected by information supply means.

FIG. 7 is a circuit diagram of a signal generator used in the present invention.

FIG. 8 is a diagram showing an example in which the present invention is used as a decorative display panel.

FIG. 9 is a diagram showing an example in which the present invention is used as a card-type information device.

FIG. 10 is a configuration diagram of a ferroelectric liquid crystal panel used in the present invention.

FIG. 11 is a diagram showing an example in which the present invention is used as a card-type information device.

FIG. 12 is a schematic diagram showing an example of a signal generator used in the present invention.

[Explanation of symbols]

 11a, 11b Polarizing plate 22 Liquid crystal cell 41 Ferroelectric liquid crystal panel 42 Information input unit 51a, 51b Polarizing plate 52 Ferroelectric liquid crystal 53a, 53b Substrate 54a, 54b Electrode 55a, 55b Alignment film 56 Reflecting plate 60 Information supply means 91 Heater

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) G09F 9/00 304 G09G 3/20 611A 5G435 G09G 3/20 611 612G 612 633L 633 660U 660 680Z 680 691F 691G 510 F term (reference) 2H088 HA06 HA21 JA17 MA20 2H089 HA19 HA40 QA11 2H093 NA11 NA31 NB09 NB13 NB14 ND42 NF17 5C006 AA28 AC02 AC24 AF67 AF69 BA12 BB12 BF42 BF44 EC06 EC08 EC13 FA41 FA47 5C080 AJ01 JJ04 DD05 KK30 KK49 KK51 5G435 AA12 AA18 BB12 EE49

Claims (9)

[Claims] 1. A ferroelectric liquid crystal module including a ferroelectric liquid crystal panel having a ferroelectric liquid crystal sandwiched between a pair of substrates, the ferroelectric liquid crystal module having an information input unit,
A ferroelectric liquid crystal module characterized in that display information displayed on a ferroelectric liquid crystal panel is input and output from a signal generator separate from the ferroelectric liquid crystal module via an information input unit. 2. The ferroelectric liquid crystal module according to claim 1, wherein the ferroelectric liquid crystal panel includes a reflector. 3. The ferroelectric liquid crystal module according to claim 1, wherein the ferroelectric liquid crystal panel is provided with a heater. 4. The ferroelectric liquid crystal module according to claim 1, wherein the ferroelectric liquid crystal module does not include a power supply circuit necessary for rewriting display information of the ferroelectric liquid crystal panel. 5. The signal generator and the information input unit are connected by an information supply unit, and electric power necessary for rewriting display information of a ferroelectric liquid crystal panel is supplied via the information supply unit or the information supply unit. 2. The ferroelectric liquid crystal module according to claim 1, wherein the power is supplied to the ferroelectric liquid crystal module from a power supply circuit provided in the means. 6. The ferroelectric liquid crystal module according to claim 5, wherein the information supply means has a function detachable from the information input unit. 7. The ferroelectric liquid crystal module according to claim 1, wherein the module is used as a clock face. 8. The ferroelectric liquid crystal module according to claim 1, wherein the module is used as a display panel for decoration. 9. The ferroelectric liquid crystal module according to claim 1, wherein the module is used as a card-type information device.