JP4787506B2 - Transflective ferroelectric liquid crystal display device - Google Patents

Description

The present invention relates to a transflective ferroelectric liquid crystal display device.

  The memory liquid crystal has a plurality of optical states and has a characteristic (memory characteristic) that maintains a specific state without applying a voltage. Therefore, when a memory-type liquid crystal is used for a liquid crystal display device, it is possible to control so as to continue to maintain a predetermined display without applying a voltage. In a display panel using a memory liquid crystal such as a ferroelectric liquid crystal using such characteristics, a scan electrode is driven only in a portion where the display needs to be changed, and a portion where the display does not need to be changed. Is known to control so as not to drive the scanning electrodes (for example, Patent Document 1).

  In addition, a polarizing plate is disposed on one of the substrates sandwiching a twisted nematic liquid crystal (TN liquid crystal) that rotates the transmitted light by 90 degrees, and a reflective polarizing plate having a reflection axis and a transmission axis is disposed on the other side. A transflective liquid crystal display device that performs reflective display and transmissive display by arranging a transflective absorption layer outside a polarizing plate and an auxiliary light source outside the transflective absorption layer is known (for example, a patent) Reference 2).

  In the transflective liquid crystal display device, when the polarizing plate is arranged so that black display is performed in an ON state (TN liquid crystal is in a transmissive state) in which an H level voltage is applied to the TN liquid crystal at the time of reflective display with the auxiliary light source turned off, At the time of transmissive display with the auxiliary light source turned on, white display is obtained in an ON state (TN liquid crystal is in a transmissive state) in which an H level voltage is applied to the TN liquid crystal. When the auxiliary light source is turned off and the TN liquid crystal is in a transmissive state, the surface color of the turned off auxiliary light source is observed from the outside to display black, and when the auxiliary light source is turned on and the TN liquid crystal is in a transmissive state, This is because the light from the light source is observed from the outside and white display is performed. That is, there is a problem that the black / white display is reversed by turning on / off the auxiliary light source even when the same level of voltage is applied to the TN liquid crystal. Therefore, in accordance with ON / OFF of the auxiliary light source, the voltage applied to the TN liquid crystal is switched (for example, from the H level to the L level) to prevent the black / white display from being inverted.

JP-A-2-131286 (pages 11, 12 and 12) Japanese Patent No. 3485541

  However, in the transflective liquid crystal display device using the memory liquid crystal, there has been no proposal regarding the direction of the reflective polarizing plate, the direction of the polarizing plate, and the alignment direction of the liquid crystal molecules of the memory liquid crystal depending on the application. .

Accordingly, an object of the present invention is to provide a transflective ferroelectric liquid crystal display device having an appropriate reflective polarizing plate direction, polarizing plate direction, and alignment direction of liquid crystal molecules of a ferroelectric liquid crystal layer. To do.

In order to solve the above-described problems, a transflective ferroelectric liquid crystal display device according to the present invention is disposed on a first substrate, a second substrate, and a first substrate, and each of the first substrates orthogonal to each other. And transmitting linearly polarized light having a vibration plane parallel to the first transmission axis and reflecting linearly polarized light having a vibration plane parallel to the first reflection axis. Reflective polarizing plate, linearly polarized light disposed on the second substrate, having a second transmission axis parallel or perpendicular to the first transmission axis, and having a vibration plane parallel to the second transmission axis The liquid crystal molecules are arranged in the first stable state by being held between the transmitting polarizing plate and the first and second substrates and maintaining either the first stable state or the second stable state. The liquid is placed in the second stable state so that the direction of the second transmission axis is inclined 45 degrees counterclockwise. It has a ferroelectric liquid crystal layer in which the orientation direction of molecules is arranged at a position inclined leftward from the second transmission axis, and an auxiliary light source provided on the reflective polarizing plate side, and includes the first transmission axis and the second transmission axis. When the reflective polarizing plate and the polarizing plate are arranged so that the transmission axis is parallel, when the auxiliary light source is turned off, white display is performed in the first stable state and black display is performed in the second stable state. When the reflective polarizing plate and the polarizing plate are arranged so that the first transmission axis and the second transmission axis are perpendicular to each other, the first stable state is maintained when the auxiliary light source is OFF. Control is performed so that black display is performed and white display is performed in the second stable state, and control is performed so that the first stable state and the second stable state are switched when the auxiliary light source is turned on.
In order to solve the above problems, a memory type liquid crystal display device according to the present invention is arranged on a first substrate, a second substrate, and a first substrate, and a first transmission axis and a first orthogonal to each other. A reflection-type polarizing plate that transmits linearly polarized light having a reflection axis of 1 and having a vibration plane parallel to the first transmission axis and reflecting linear polarization having a vibration plane parallel to the first reflection axis; A polarizing plate that is disposed on the second substrate, has a second transmission axis parallel or perpendicular to the first transmission axis, and transmits linearly polarized light having a vibration plane parallel to the second transmission axis; It is sandwiched between the first and second substrates and maintains either the first stable state or the second stable state, and the alignment direction of the liquid crystal molecules in the first stable state is determined from the second transmission axis. And a memory liquid crystal layer arranged so as to have an inclination of approximately 45 °.

  The memory type liquid crystal device according to the present invention preferably further includes an auxiliary light source provided on the reflective polarizing plate side.

  Furthermore, in the memory type liquid crystal device according to the present invention, it is preferable to dispose the reflective polarizing plate and the polarizing plate so that the first transmission axis and the second transmission axis are parallel to each other.

  Furthermore, in the memory-type liquid crystal device according to the present invention, it is preferable that the memory-type liquid crystal layer is set to perform white display when the memory-type liquid crystal layer is maintained in the first stable state.

  Furthermore, the memory type liquid crystal device according to the present invention further includes an auxiliary light source provided on the reflective polarizing plate side, and the memory type liquid crystal layer is maintained in the first stable state with the auxiliary light source turned on. In such a case, it is preferable that black display is performed.

  Furthermore, in the memory type liquid crystal device according to the present invention, it is preferable to dispose the reflective polarizing plate and the polarizing plate so that the first transmission axis and the second transmission axis are perpendicular to each other.

  Furthermore, in the memory type liquid crystal device according to the present invention, it is preferable that the memory type liquid crystal layer is set to perform black display when the memory type liquid crystal layer is maintained in the first stable state.

  Further, the memory type liquid crystal device according to the present invention further includes an auxiliary light source provided on the reflective polarizing plate side, and the memory type liquid crystal layer is maintained in the first stable state with the auxiliary light source turned on. In such a case, it is preferable that white display is performed.

  Furthermore, the memory-type liquid crystal display device according to the present invention preferably further includes a light absorption layer that is disposed between the reflective polarizing plate and the auxiliary light source and absorbs light in a partial region. This makes it possible to display the surface color of the auxiliary light source observed on the memory type liquid crystal display device in black when the auxiliary light source is turned off and the memory type liquid crystal is in a transmissive state.

  Furthermore, the memory-type liquid crystal display device according to the present invention preferably further includes a light absorption layer that is disposed between the reflective polarizing plate and the auxiliary light source and absorbs part of the light in the visible light region. This makes it possible to display the surface color of the auxiliary light source observed on the memory type liquid crystal display device in black when the auxiliary light source is turned off and the memory type liquid crystal is in a transmissive state.

  Furthermore, in the memory type liquid crystal display device according to the present invention, it is preferable that a surface of the auxiliary light source is provided with a reflective layer that reflects a part of the light in the visible light region. As a result, it is possible to control the surface color of the auxiliary light source observed on the memory type liquid crystal display device when the auxiliary light source is turned off and the memory type liquid crystal is in a transmissive state.

  Furthermore, the memory-type liquid crystal display device according to the present invention further includes an auxiliary light source provided on the reflective polarizing plate side, which is disposed on one of the first and second substrates, and is provided on the memory-type liquid crystal layer. A scanning electrode for applying a voltage; and a signal electrode disposed on the other of the first and second substrates for applying a voltage to the memory liquid crystal layer; It is preferable to control the polarity of the drive waveform applied to the scan electrode or the signal electrode to be reversed.

  The memory-type liquid crystal display device according to the present invention further includes a power supply unit for supplying power to the memory-type liquid crystal display device, and the inversion control unit inverts the polarity of the voltage generated in the power supply unit to It is preferable to control so that the stable state of the liquid crystal is reversed from one to the other.

  Further, the memory type liquid crystal display device according to the present invention has an arithmetic circuit, and the inversion control unit converts the normal display data into the inverted display data by the arithmetic circuit, thereby changing the stable state of the memory type liquid crystal from one to the other. It is preferable to control so as to be reversed.

  According to the present invention, an optimal display, in particular, a black display can be performed by appropriately disposing the polarizing plate and the reflective polarizing plate and appropriately arranging the directions of the liquid crystal molecules in the first and second ferroelectric states. It was possible to provide a possible liquid crystal panel.

  Hereinafter, a liquid crystal display device 100 according to the present invention will be described with reference to the drawings.

  FIG. 1 shows a schematic block diagram of a liquid crystal display device 100 common to the embodiments.

  The liquid crystal display device 100 includes a liquid crystal panel 20, a control unit 21, a drive voltage waveform control circuit 22, a scan drive voltage waveform generation circuit 23 for applying a voltage waveform to each scan electrode 13a arranged in the liquid crystal panel 20, and a liquid crystal A signal drive voltage waveform generation circuit 24 for applying a voltage waveform to each signal electrode 13b arranged in the panel 20, a power supply unit 25 composed of a solar cell, a secondary battery, etc., a display data storage unit 27, a RAM 30, The ROM 31 and the clock circuit 50 are included.

  Further, the liquid crystal display device 100 includes an auxiliary light source 60 disposed on the back side of the liquid crystal panel 20, an auxiliary light source control circuit 61 for controlling ON / OFF of the auxiliary light source 60, and the user setting ON / OFF of the auxiliary light source 60. An auxiliary light source switch 62 is provided. Although not clearly shown in FIG. 1, each component of the liquid crystal display device 100 is configured to be able to receive power supply from the power supply unit 25.

  The control unit 21 creates display data using time information received from the clock circuit 50 in accordance with a program stored in advance in the RAM 30 or the ROM 31, stores the display data in the display data storage unit 27, and displays the display data corresponding to the time information. Is displayed on the liquid crystal panel 20 so as to output a control signal to the drive voltage waveform control circuit 22.

  Further, the control unit 21 controls the auxiliary light source control circuit 61 to turn on the auxiliary light source 60 when the user turns on the auxiliary light source switch 62 when the surroundings of the liquid crystal display device 100 are dark or the like. Configured.

  Further, as will be described later, the control unit 21 detects that the auxiliary light source switch 62 is turned on, controls the drive voltage waveform control circuit 22, inverts the polarity of the ferroelectric liquid crystal 10, and performs the auxiliary light source 60. Regardless of whether the display is on or off, control is performed so that the display on the liquid crystal panel 20 is not reversed.

  FIG. 2 shows a cross-sectional view of the liquid crystal panel 20 and the auxiliary light source 60 common to each embodiment.

  The liquid crystal panel 20 includes a first transparent glass substrate 11a, a second transparent glass substrate 11b, a scanning electrode 13a provided on the first transparent glass substrate 11a, and a signal provided on the second transparent glass substrate 11b. The electrode 13b, the polymer alignment film 14a applied on the scanning electrode 13a and rubbed, the polymer alignment film 14b applied on the signal electrode 13b and rubbed, the seal member 12, the first and second transparent films The ferroelectric liquid crystal 10 sandwiched between the glass substrates 11a and 11b and sealed by the sealing member 12, the reflective polarizing plate 16 provided outside the first transparent glass substrate 11a, and the second transparent glass substrate 11b. The polarizing plate 15 provided on the outer side.

  As the ferroelectric liquid crystal 10, “Felix 501” manufactured by AZ Materials Co., Ltd. was used, and was sandwiched between the first and second transparent glass substrates 11a and 11b with a thickness of approximately 1.7 μm.

  The reflective polarizing plate 16 is composed of a multilayer film such as a polyester resin, has a transmission axis and a reflection axis orthogonal to each other, transmits linearly polarized light having a vibration plane parallel to the transmission axis, and vibrates parallel to the reflection axis. It has a function of reflecting linearly polarized light having a surface.

  In FIG. 2, an arrow A indicates external light incident on the liquid crystal panel 20 from the outside, and an arrow B indicates light incident on the liquid crystal panel from the auxiliary light source 60.

  In consideration of low power consumption and thinness, a backlight using an organic EL cell as a light emitting element is arranged as an auxiliary light source 60 below the reflective polarizing plate 16 of the liquid crystal panel 20. Note that an auxiliary light source using another light-emitting element can also be used.

  In FIG. 2, five scanning electrodes 13 a are shown for convenience, but in this embodiment, 40 scanning electrodes 13 a configured by a transparent conductive film pattern are arranged over the entire liquid crystal panel 20. Also. Although not clearly shown in FIG. 2, 50 signal electrodes 13b formed of a transparent conductive film pattern are arranged over the entire liquid crystal panel 20 so as to be orthogonal to the scanning electrodes 13a. Accordingly, each point where the scanning electrode 13a and the signal electrode 13b intersect becomes each pixel (2000 pixels) of the liquid crystal panel 20.

A first embodiment will be described.
FIG. 3 shows the arrangement of the polarizing plate 15 and the reflective polarizing plate 16 in the liquid crystal panel 20 according to the first embodiment.

As shown in FIG. 3, the transmission axis of the polarizing plate 15 (a ₁₎ and the transmission axis of the reflective polarizer 16 (b ₁₎ is arranged to run in parallel. In addition, the orientation direction of the long axis of the liquid crystal molecules of the ferroelectric liquid crystal 10 in the first ferroelectric state is tilted counterclockwise by θ ₁ (approximately 45 °) from the transmission axis (a ₁ ) of the polarizing plate 15. It was. Further, the alignment direction of the long axes of the liquid crystal molecules of the ferroelectric liquid crystal 10 in the second ferroelectric state is set to a position inclined by θ ₂ counterclockwise from the transmission axis (a ₁ ) of the polarizing plate 15. At two positions along the liquid crystal cone, the alignment direction of the long axis of the liquid crystal molecule of the ferroelectric liquid crystal 10 in the first ferroelectric state and the long axis of the liquid crystal molecule of the ferroelectric liquid crystal 10 in the second ferroelectric state The arrangement direction of was arranged. In the ferroelectric liquid crystal 10 in the first example, θ ₂ was set to be other than 0 °. Accordingly, the arrangement direction of the long axis of the liquid crystal molecules of the ferroelectric liquid crystal 10 in the second ferroelectric state, the transmission axis of the polarizing plate 15 (a ₁₎ and the transmission axis of the reflective polarizer 16 and (b ₁₎ is It is not completely parallel.

When the ferroelectric liquid crystal utilizes birefringence, the relationship between the amount of light incident on the ferroelectric liquid crystal (I _in ) and the amount of light emitted (I _out ) is generally expressed by the following equation (1).

I _out = I _in · sin ² 2θ · sin ² (R / λ) π (1)
Here, θ represents the inclination from the transmission axis (a ₁ ) of the polarizing plate 15, R represents retardation, and λ represents the wavelength of light incident on the ferroelectric liquid crystal.

When birefringence is used, as can be understood from the above equation (1), θ ₁ is 45 ° in the _first ferroelectric state, but as shown in equation (1), the amount of emitted light Since (I _out ) is affected by the wavelength λ of the incident light, I _out is not equal to I _in .

  FIG. 4 shows the relationship between the voltage applied to the ferroelectric liquid crystal 10 and the light transmittance in the liquid crystal panel 20 according to the first embodiment.

  4A shows a state where the auxiliary light source 60 is turned off, and FIG. 4B shows a state where the auxiliary light source 60 is turned on. The horizontal axis of each graph is applied voltage (V) applied between the scanning electrode 13a and the signal electrode 13b with respect to the scanning electrode 13a of the liquid crystal panel 20 (that is, applied to the ferroelectric liquid crystal 10). The vertical axis represents the light transmittance of the liquid crystal panel 20.

  A state where the auxiliary light source 60 is turned off will be described with reference to FIG.

When the polarity of the applied voltage is changed to invert the ferroelectric liquid crystal 10 to the first ferroelectric state, the alignment direction of the major axis of the liquid crystal molecules of the ferroelectric liquid crystal 10 is the transmission axis ( a ₁ ) and the transmission axis (b ₁ ) of the reflective polarizing plate 16 do not coincide with each other, and tilt with an angle θ ₁ (approximately 45 °) with respect to the transmission axis (a ₁ ). The transmission axis of the polarizer 15 enters the liquid crystal panel 20 (a ₁₎ and the external light A having a vibration plane parallel strength by birefringence of ferroelectric liquid crystal 10, the transmission axis of the reflective polarizer 16 (b ₁ ) And is reflected by the reflective polarizing plate 16 (reflection state). Therefore, when the auxiliary light source 60 is turned off, in the first ferroelectric state, the external light A incident on the liquid crystal panel 20 is reflected by the reflective polarizing plate 16 and incident again on the ferroelectric liquid crystal 10 and again strong. Since the vibration direction of light is rotated by the birefringence of the dielectric liquid amount 10 and has a vibration surface parallel to the transmission axis (a ₁ ) of the polarizing plate 15, the light is transmitted through the polarizing plate 15 to display white. It becomes. The light transmittance at this time is Th ₁ -OFF in FIG.

When the polarity of the applied voltage is changed to invert the ferroelectric liquid crystal 10 to the second ferroelectric state, the alignment direction of the major axes of the liquid crystal molecules of the ferroelectric liquid crystal 10 is the transmission axis ( a ₁₎ and a reflective transmission axis of the polarizing plate 16 than parallel to the (b ₁₎ by (the angle theta ₂ tilts). Therefore, the outer having a transmission axis that enters the liquid crystal panel 20 (a ₁₎ and parallel to the vibration surface Most of the light A passes through the liquid crystal panel 20 (transmission state) and is reflected from the surface of the auxiliary light source 60. Since the surface of the auxiliary light source 60 is normally dark, when the auxiliary light source 60 is turned off, in the second ferroelectric state, the light incident on the liquid crystal panel 20 is reflected by the surface of the auxiliary light source 60, and the liquid crystal panel 20 Above is black. The light transmittance at this time is Tl ₁ -OFF in FIG.

Thus, when the auxiliary light source 60 is turned off, the voltage applied to the ferroelectric liquid crystal 10 is increased (beyond the voltage value V ₁ at which the light transmittance starts to increase), and the increase in light transmittance is saturated. If the voltage value V ₂ (positive threshold value) or higher is applied, the ferroelectric liquid crystal 10 maintains the first ferroelectric state without applying a voltage thereafter (ie, 0 V application), and the liquid crystal panel 20 displays white. To maintain. Further, the voltage applied to the ferroelectric liquid crystal 10 (beyond the voltage value V ₃ the light transmittance begins to decrease) by decreasing the voltage value V ₄ a decrease in the light transmittance reaches saturation _(negative threshold) Assuming the following, the ferroelectric liquid crystal 10 maintains the second ferroelectric state and the liquid crystal panel 20 maintains black display even if no voltage is applied thereafter (that is, 0 V is applied).

  A state where the auxiliary light source 60 is turned on will be described with reference to FIG.

When the polarity of the applied voltage is changed to invert the ferroelectric liquid crystal 10 to the first ferroelectric state, the alignment direction of the major axis of the liquid crystal molecules of the ferroelectric liquid crystal 10 is the transmission axis ( a ₁ ) and the transmission axis (b ₁ ) of the reflective polarizing plate 16 do not coincide with each other. The light B having a vibration plane parallel to the transmission axis (b ₁ ) of the reflective polarizing plate 16 incident on the liquid crystal panel 20 from the auxiliary light source 60 is transmitted through the polarizing plate 15 due to the birefringence of the ferroelectric liquid crystal 10. It has a vibration surface substantially perpendicular to (a ₁ ) and is absorbed by the polarizing plate 15. Therefore, when the auxiliary light source 60 is turned on, in the first ferroelectric state, light from the auxiliary light source 60 is absorbed by the polarizing plate 15 and black display is performed on the liquid crystal panel 20. The light transmittance at this time is Tl ₁ -ON in FIG.

When the polarity of the applied voltage is changed to invert the ferroelectric liquid crystal 10 to the second ferroelectric state, the alignment direction of the major axis of the liquid crystal molecules of the ferroelectric liquid crystal 10 is the transmission axis (a ₁ ) and parallel to the transmission axis (b ₁ ) of the reflective polarizing plate 16 (inclined by an angle θ ₂ ), so that the vibration is parallel to the transmission axis (b ₁ ) incident on the liquid crystal panel 20 from the auxiliary light source 60. Most of the light B having a surface is transmitted through the liquid crystal panel 20 (transmission state). Therefore, when the auxiliary light source 60 is turned on, in the second ferroelectric state, light incident on the liquid crystal panel 20 from the auxiliary light source 60 is observed on the liquid crystal panel 20 and white display is performed on the liquid crystal panel 20. The light transmittance at this time is Th ₁ -ON in FIG.

In this way, the voltage applied to the ferroelectric liquid crystal 10 is increased (beyond the voltage value V ₁ at which the light transmittance starts increasing), and the voltage value V ₂ (positive) at which the increase in light transmittance is saturated. If the threshold value is greater than or equal to the threshold value, the ferroelectric liquid crystal 10 maintains the first ferroelectric state without applying a voltage thereafter (that is, 0 V is applied), and the liquid crystal panel 20 maintains the black display. Similarly, strong the voltage applied to the ferroelectric liquid crystal 10 (beyond the voltage value V ₃ the light transmittance begins to decrease) by decreasing the voltage value V _{4 (the} negative threshold decrease in light transmittance is saturated ) If the following is set, the ferroelectric liquid crystal 10 maintains the second ferroelectric state and maintains the white display even if no voltage is applied thereafter (that is, 0 V is applied).

  As understood from FIGS. 4A and 4B, in the liquid crystal panel 20 according to the first embodiment, when the auxiliary light source 60 is switched between ON and OFF, the ferroelectric liquid crystal 10 is in the same ferroelectric state. Even if it exists, the black / white display is reversed. For example, in a state where the auxiliary light source 60 is turned off, a portion of the liquid crystal panel 20 performing white display by being maintained in the first ferroelectric state (the first ferroelectric state in FIG. 4A) When the auxiliary light source 60 is turned on, the display is black (first ferroelectric state in FIG. 4B). Therefore, in this embodiment, the ferroelectric liquid crystal 10 is controlled to invert the polarity (invert from one ferroelectric state to the other ferroelectric state) in accordance with switching of the auxiliary light source 60 between ON and OFF. Then, control is performed so that the black / white display of the liquid crystal panel 20 does not change.

By the way, when the auxiliary light source 60 is turned on and the ferroelectric liquid crystal 10 is inverted to the second ferroelectric state, white display on the liquid crystal panel 20 (Th ₁ -ON in FIG. 4B) indicates that the auxiliary light source 60 is turned on. The light transmittance is lower than the white display (Th ₁ -OFF in FIG. 4A) in the liquid crystal panel 20 when the ferroelectric liquid crystal 10 is turned off and inverted to the first ferroelectric state (that is, Th ₁ -OFF in FIG. 4A). The white display is even more gray.)

Even in the white display on the liquid crystal panel 20 (Th ₁ -OFF in FIG. 4A) when the auxiliary light source 60 is turned off and the ferroelectric liquid crystal 10 is inverted to the first ferroelectric state, the ferroelectric liquid crystal 10 Incident light that is not corrected so as to have a vibration plane that is slightly perpendicular to the transmission axis (b ₁ ) of the reflective polarizing plate 16, and is not reflected by the reflective polarizing plate 16. Light transmittance is reduced. However, in the white display on the liquid crystal panel 20 when the auxiliary light source 60 is turned ON and the ferroelectric liquid crystal 10 is inverted to the second ferroelectric state (Th ₁ -ON in FIG. 4B), the second strong light source 60 is turned on. Since the alignment direction of the liquid crystal molecules in the dielectric state is shifted from the transmission axis (b ₁ ) of the reflective polarizing plate 16 by an angle θ ₂ , most of the light B incident on the liquid crystal panel 20 from the auxiliary light source 60 is transmitted through the polarizing plate 15. This is because it is displaced from the axis (a ₁ ), is reflected by the polarizing plate 15 and cannot pass through the liquid crystal panel 20, and the light transmittance is further reduced.
Further, when the auxiliary light source 60 is turned off and the ferroelectric liquid crystal 10 is inverted to the second ferroelectric state, black display on the liquid crystal panel 20 (Tl ₁ -OFF in FIG. 4A) turns the auxiliary light source 60 off. The light transmittance is higher than that of the black display (Tl ₁ -ON in FIG. 4B) when the ferroelectric liquid crystal 10 is turned on and inverted to the first ferroelectric state (Tl ₁ -ON in FIG. 4B) (ie, The black display becomes more gray.)

Even in black display on the liquid crystal panel 20 when the auxiliary light source 60 is turned ON and the ferroelectric liquid crystal 10 is inverted to the first ferroelectric state (Tl ₁ -ON in FIG. 4B), the ferroelectric liquid crystal 10 Incident light that is not corrected so as to have a vibration plane that is slightly perpendicular to the transmission axis (a ₁ ) of the polarizing plate 15, is not absorbed by the polarizing plate 15, and has a light transmittance. To increase. However, in the black display (Th ₁ -OFF in FIG. 4A) in the liquid crystal panel 20 when the auxiliary light source 60 is turned off and the ferroelectric liquid crystal 10 is inverted to the second ferroelectric state, the second strong light source 60 is turned on. Since the alignment direction of the liquid crystal molecules in the dielectric state is shifted from the transmission axis (b ₁ ) of the reflective polarizing plate 16 by an angle θ ₂ , most of the external light A incident on the liquid crystal panel 20 is reflected by the reflective polarizing plate 16. This is because the light transmittance is further increased as observed on the liquid crystal panel 20.
Therefore, the liquid crystal panel 20 according to the first embodiment can clearly display black display (Tl ₁ -ON in FIG. 4B) with the auxiliary light source 60 turned on (light transmittance is high). Since black display closer to zero can be performed), the auxiliary light source 60 is suitable for use as a display for a mobile phone that emphasizes transmission, which is often used at all times.

  FIG. 5 shows an example in which the liquid crystal panel 20 according to the first embodiment is used in a mobile phone.

  FIG. 5A shows an example in which the liquid crystal panel 20 performs display using the auxiliary light source 60 in the mobile phone 2. In order to save power, the auxiliary light source 60 is turned off when the mobile phone is not operated for a certain period of time. However, when the user turns on the auxiliary light source switch 62 disposed on the mobile phone 2, FIG. ), The auxiliary light source 60 disposed on the back side of the liquid crystal panel 20 is turned on.

  As described above, when the auxiliary light source 60 is simply turned on, the black / white display is reversed, and the display is performed as shown in FIG. Therefore, in the mobile phone 2, when the auxiliary light source switch 62 is turned on, the control unit 21 detects that the auxiliary light source switch 62 is turned on, controls the drive voltage waveform control circuit 22, and controls the strong voltage corresponding to each pixel of the liquid crystal panel 20. The polarity of the dielectric liquid crystal 10 is reversed, and the display on the liquid crystal panel 20 is controlled as shown in FIG.

As described above, black display with the auxiliary light source 60 turned off (Tl ₁ -OFF in FIG. 4A) is black display with the auxiliary light source 60 turned off (Tl in FIG. 4B). _1- ON), the light transmittance is increased, but the state in which the auxiliary light source 60 is turned off is a state in which the mobile phone is not normally used.

  FIG. 6 shows an example of a driving voltage waveform for driving the liquid crystal panel 20.

  6A shows an example of a scanning voltage waveform applied to one scanning electrode 13a, and FIG. 6B shows an example of a signal voltage waveform applied to one signal electrode 13b. 6 (c) shows the combined voltage waveform of (a) and (b).

  FIG. 6 shows driving voltage waveforms for two frames. In the figure, “ON” indicates white display when the auxiliary light source “OFF” shown in FIG. 4A is displayed, and “OFF” similarly indicates FIG. The black display in a) is shown. Here, one scanning period is used to execute display based on one display data. One frame consists of a reset period (Rs) and a scanning period. One scanning period consists of a selection period (Se) and a non-selection period (NSe).

In the reset period (Rs), the ferroelectric liquid crystal 10 is in the first ferroelectric state in which the first half is white display (transmission state) and the second half is black display (non-transmission state) regardless of the previous display state. The second ferroelectric state is forcibly reset. In the reset period (Rs), the scanning voltage waveform (a) is applied with + 20V in the first half and −20V in the second half. In the signal voltage waveform (b), + 5V and -5V voltages are repeatedly applied at predetermined intervals. As a result, a voltage corresponding to the composite voltage waveform (c), that is, a voltage equal to or higher than the positive threshold V ₂ is applied to the pixel of the ferroelectric liquid crystal 10 in the first half of the reset period (Rs). state, negative threshold V ₄ less voltage is reset to a second ferroelectric state is applied in the second half. By providing the reset period, it is possible to maintain good display in the liquid crystal panel using the ferroelectric liquid crystal.

  In the first embodiment, when the driving voltage as shown in FIG. 6 is applied with the auxiliary light source 60 turned off, the first frame is set to the first ferroelectric state and white display is performed. In the second frame, the case where black display is performed by setting the second ferroelectric state is shown.

  A second embodiment will be described.

  The cross-sectional view of the liquid crystal panel 20 and the auxiliary light source 60 according to the second embodiment are the same as those shown in FIG. 2 except for the arrangement of the polarizing plate 15 and the reflective polarizing plate 16, and thus the description thereof is omitted.

  Also in the third embodiment, “Felix 501” manufactured by AZ Materials is used as the ferroelectric liquid crystal 10, and the thickness is approximately 1.7 μm between the first and second transparent glass substrates 11 a and 11 b. I pinched it.

  FIG. 7 shows the arrangement of the polarizing plate 15 and the reflective polarizing plate 16 in the liquid crystal panel 20 according to the second embodiment.

As shown in FIG. 7, the transmission axis of the polarizing plate 15 (a ₂₎ the transmission axis of the reflective polarizer 16 (b ₂₎ is arranged perpendicular. Further, the position in which the long axis alignment direction of the liquid crystal molecules of the ferroelectric liquid crystal 10 in the first ferroelectric state is tilted counterclockwise by θ ₃ (approximately 45 °) from the transmission axis (a ₂ ) of the polarizing plate 15. It was. Further, the arrangement direction of the long axes of the liquid crystal molecules of the ferroelectric liquid crystal 10 in the second ferroelectric state is set to a position inclined by θ ₄ counterclockwise from the transmission axis (a ₂ ) of the polarizing plate 15. At two positions along the liquid crystal cone, the alignment direction of the long axis of the liquid crystal molecule of the ferroelectric liquid crystal 10 in the first ferroelectric state and the long axis of the liquid crystal molecule of the ferroelectric liquid crystal 10 in the second ferroelectric state The arrangement direction of was arranged. Incidentally, in the ferroelectric liquid crystal 10 in the second embodiment, theta ₄ was set to be other than 0 °. Therefore, the arrangement direction of the long axes of the liquid crystal molecules of the ferroelectric liquid crystal 10 in the second ferroelectric state is not completely parallel to the transmission axis (a ₂ ) of the polarizing plate 15.

As described above using Equation (1), in the first ferroelectric state, θ ₃ is 45 °. However, since birefringence is used, I _out is not equal to I _in .

  FIG. 8 shows the relationship between the voltage applied to the ferroelectric liquid crystal 10 and the light transmittance in the liquid crystal panel 20 according to the second embodiment.

  FIG. 8A shows a state where the auxiliary light source 60 is OFF, and FIG. 8B shows a state where the auxiliary light source 60 is ON. The horizontal axis of each graph is applied voltage (V) applied between the scanning electrode 13a and the signal electrode 13b with respect to the scanning electrode 13a of the liquid crystal panel 20 (that is, applied to the ferroelectric liquid crystal 10). The vertical axis represents the light transmittance of the liquid crystal panel 20.

  A state in which the auxiliary light source 60 is turned off will be described with reference to FIG.

When the polarity of the applied voltage is changed to invert the ferroelectric liquid crystal 10 to the first ferroelectric state, the alignment direction of the major axis of the liquid crystal molecules of the ferroelectric liquid crystal 10 is the transmission axis ( a ₂ ) and the transmission axis (b ₂ ) of the reflective polarizing plate 16 do not coincide with each other, and tilt with an angle θ ₃ (approximately 45 °) with respect to the transmission axis (a ₂ ). The transmission axis of the polarizer 15 enters the liquid crystal panel 20 (a ₂₎ and the external light A having a vibration plane parallel strength by birefringence of ferroelectric liquid crystal 10, the transmission axis of the reflective polarizer 16 (b ₂ ) And is transmitted through the liquid crystal panel 20 (transmitted state) and reflected from the surface of the auxiliary light source 60. Since the surface of the auxiliary light source 60 is usually dark, when the auxiliary light source 60 is turned off, in the first ferroelectric state, the light incident on the liquid crystal panel 20 is reflected by the surface of the auxiliary light source 60 and the liquid crystal panel 20. Above is black. The light transmittance at this time is Tl ₂ -OFF in FIG.

When the polarity of the applied voltage is changed to invert the ferroelectric liquid crystal 10 to the second ferroelectric state, the alignment direction of the major axis of the liquid crystal molecules of the ferroelectric liquid crystal 10 is the transmission axis (a ₂ ) and parallel (inclined by the angle θ ₃ ), and the external light A having a vibration plane parallel to the transmission axis (a ₂ ) incident on the liquid crystal panel 20 is transmitted through the transmission axis (b ₂ ) of the reflective polarizing plate 16. And is reflected by the reflective polarizing plate 16 (reflection state). Therefore, when the auxiliary light source 60 is turned off, in the second ferroelectric state, the external light A incident on the liquid crystal panel 20 is reflected by the reflective polarizing plate 16 and white display is performed on the liquid crystal panel 20. The light transmittance at this time is Th ₂ -OFF in FIG.

Thus, when the auxiliary light source 60 is turned off, the voltage applied to the ferroelectric liquid crystal 10 is increased (beyond the voltage value V ₁ at which the light transmittance starts to increase), and the increase in light transmittance is saturated. If the voltage value V ₂ (positive threshold value) or higher is applied, the ferroelectric liquid crystal 10 maintains the first ferroelectric state without applying a voltage thereafter (ie, 0 V application), and the liquid crystal panel 20 displays black. To maintain. Further, the voltage applied to the ferroelectric liquid crystal 10 (beyond the voltage value V ₃ the light transmittance begins to decrease) by decreasing the voltage value V ₄ a decrease in the light transmittance reaches saturation _(negative threshold) Assuming the following, the ferroelectric liquid crystal 10 maintains the second ferroelectric state and the liquid crystal panel 20 maintains white display even if no voltage is applied thereafter (that is, 0 V is applied).

  A state in which the auxiliary light source 60 is turned on will be described with reference to FIG.

When the polarity of the applied voltage is changed to invert the ferroelectric liquid crystal 10 to the first ferroelectric state, the alignment direction of the major axis of the liquid crystal molecules of the ferroelectric liquid crystal 10 is the transmission axis ( a ₂ ) and the transmission axis (b ₂ ) of the reflective polarizing plate 16 do not coincide with each other. The light B having a vibration plane parallel to the transmission axis (b ₂ ) of the reflective polarizing plate 16 incident on the liquid crystal panel 20 from the auxiliary light source 60 is transmitted through the polarizing plate 15 due to the birefringence of the ferroelectric liquid crystal 10. It has a vibration surface substantially parallel to (a ₂ ), passes through the polarizing plate 15 (transmission state), and is observed on the liquid crystal panel 20. Therefore, when the auxiliary light source 60 is turned on, the light from the auxiliary light source 60 is displayed in white on the liquid crystal panel 20 in the first ferroelectric state. The light transmittance at this time is Th ₂ -ON in FIG.

When the polarity of the applied voltage is changed to invert the ferroelectric liquid crystal 10 to the second ferroelectric state, the alignment direction of the major axis of the liquid crystal molecules of the ferroelectric liquid crystal 10 is the transmission axis (a ₂ ) and parallel (inclined by an angle θ ₄ ). The light B having a vibration plane parallel to the transmission axis (b ₂ ) incident on the liquid crystal panel 20 from the auxiliary light source 60 has a vibration plane perpendicular to the transmission axis (a ₂ ), and is thus absorbed by the polarizing plate 15 (reflection). State), not observed on the surface of the liquid crystal panel 20. Therefore, when the auxiliary light source 60 is turned on, black display is performed on the liquid crystal panel 20 in the second ferroelectric state. The light transmittance at this time is Tl ₂ -ON in FIG.

In this way, the voltage applied to the ferroelectric liquid crystal 10 is increased (beyond the voltage value V ₁ at which the light transmittance starts increasing), and the voltage value V ₂ (positive) at which the increase in light transmittance is saturated. If the threshold value is greater than or equal to the threshold value, the ferroelectric liquid crystal 10 maintains the first ferroelectric state and the liquid crystal panel 20 maintains white display without applying a voltage thereafter (that is, applying 0 V). Similarly, strong the voltage applied to the ferroelectric liquid crystal 10 (beyond the voltage value V ₃ the light transmittance begins to decrease) by decreasing the voltage value V _{4 (the} negative threshold decrease in light transmittance is saturated ) If the following is set, the ferroelectric liquid crystal 10 maintains the second ferroelectric state and maintains a black display even if no voltage is applied thereafter (that is, 0 V is applied).

  As understood from FIGS. 8A and 8B, in the liquid crystal panel 20 according to the second embodiment, when the auxiliary light source 60 is switched between ON and OFF, the ferroelectric liquid crystal 10 is in the same ferroelectric state. Even if it exists, the black / white display is reversed. Therefore, in this embodiment, the ferroelectric liquid crystal 10 is controlled to invert the polarity (invert from one ferroelectric state to the other ferroelectric state) in accordance with switching of the auxiliary light source 60 between ON and OFF. Then, control is performed so that the black / white display of the liquid crystal panel 20 does not change.

By the way, when the auxiliary light source 60 is turned off and the ferroelectric liquid crystal 10 is inverted to the second ferroelectric state, white display on the liquid crystal panel 20 (Th ₂ -OFF in FIG. 8A) turns the auxiliary light source 60 on. The light transmittance is lower than that of the white display (Th ₂ -ON in FIG. 8B) in the liquid crystal panel 20 when the ferroelectric liquid crystal 10 is turned on and inverted to the first ferroelectric state (that is, Th ₂ -ON in FIG. 8B). The white display is even more gray.)

Even in the white display (Th ₂ -ON in FIG. 8B) on the liquid crystal panel 20 when the auxiliary light source 60 is turned on and the ferroelectric liquid crystal 10 is inverted to the first ferroelectric state, the ferroelectric liquid crystal 10 Incident light which is not corrected so as to have a vibration plane slightly parallel to the transmission axis (a ₂ ) of the polarizing plate 15 is generated and absorbed by the polarizing plate 15, and the light transmittance is reduced. To do. However, in the white display (Th ₂ -OFF in FIG. 8A) on the liquid crystal panel 20 when the auxiliary light source 60 is turned off and the ferroelectric liquid crystal 10 is inverted to the second ferroelectric state, the second strong light source 60 is turned on. Since the alignment direction of the liquid crystal molecules in the dielectric state is shifted from the transmission axis (a ₂ ) of the polarizing plate 15 by an angle θ ₄ , most of the external light A incident on the liquid crystal panel 20 is transmitted through the transmission axis (b ₁₂ ), and is not reflected by the reflective polarizing plate 16, and the light transmittance is further reduced.
Further, when the auxiliary light source 60 is turned on and the ferroelectric liquid crystal 10 is inverted to the second ferroelectric state, black display on the liquid crystal panel 20 (Tl ₂ -ON in FIG. 8B) indicates that the auxiliary light source 60 is turned on. The light transmittance is higher than black display (Tl ₂ -OFF in FIG. 8A) in the liquid crystal panel 20 when the ferroelectric liquid crystal 10 is turned off and inverted to the first ferroelectric state (ie, Tl ₂ -OFF in FIG. 8A). The black display becomes more gray.)

Even in black display on the liquid crystal panel 20 (Tl ₂ -OFF in FIG. 8A) when the auxiliary light source 60 is turned off and the ferroelectric liquid crystal 10 is inverted to the first ferroelectric state, the ferroelectric liquid crystal 10 Incident light which is not corrected so as to have a vibration plane slightly parallel to the transmission axis (b ₂ ) of the reflective polarizing plate 16 is generated, reflected by the reflective polarizing plate 16 and light transmittance. Will increase. However, in the black display (Tl ₂ -ON in FIG. 8B) in the liquid crystal panel 20 when the auxiliary light source 60 is turned on and the ferroelectric liquid crystal 10 is inverted to the second ferroelectric state, the second strong light source 60 is turned on. Since the alignment direction of the liquid crystal molecules in the dielectric state is shifted from the transmission axis (a ₂ ) of the polarizing plate 15 by an angle θ ₄ , much of the light B incident on the liquid crystal panel 20 is not absorbed by the polarizing plate 15, and the liquid crystal This is because the light transmittance is further increased as observed on the panel 20.
Therefore, the liquid crystal panel 20 according to the second embodiment can clearly display black display (Tl ₂ -OFF in FIG. 8A) with the auxiliary light source 60 turned off (light transmittance is low). It is suitable for use in a display unit such as a wristwatch that emphasizes reflection, which often performs display using external light, without using the auxiliary light source 60 normally. ing. The reason why the auxiliary light source 60 is not normally used in a wristwatch or the like is to avoid power consumption.

FIG. 9 shows an example in which the liquid crystal panel 20 according to the second embodiment is used for a wristwatch.
FIG. 9A shows an example in which the liquid crystal panel 20 performs display using external light without using the auxiliary light source 60 in the timepiece 1. When the outside becomes dark, when the user turns on the auxiliary light source switch 62 arranged on the watch 1, the auxiliary light source 60 arranged on the back side of the liquid crystal panel 20 in FIG. 9A is turned on.

  As described above, when the auxiliary light source 60 is simply turned on, the black / white display is reversed and displayed as shown in FIG. 9B. Therefore, in the timepiece 1, when the auxiliary light source switch 62 is turned on, the control unit 21 detects that the auxiliary light source switch 62 is turned on, controls the drive voltage waveform control circuit 22, and ferroelectrics corresponding to the respective pixels of the liquid crystal panel 20. The polarity of the liquid crystal 10 was reversed, and the display on the liquid crystal panel 20 was controlled as shown in FIG.

As described above, black display with the auxiliary light source 60 turned on (Tl ₂ -ON in FIG. 8B) is black display with the auxiliary light source 60 turned off (Tl in FIG. 8A). ₂₋ OFF), the light transmittance increases, but the state where the auxiliary light source 60 is used is not usually a big problem because the periphery of the watch is often dark.

  The drive voltage waveform for driving the liquid crystal panel 20 according to the second embodiment is also the same as that shown in the first embodiment shown in FIG.

Further, in the first and second embodiments, the position in which the long axis alignment direction of the liquid crystal molecules of the ferroelectric liquid crystal in the first ferroelectric state is tilted counterclockwise from the transmission axis (a ₁ ) of the polarizing plate 15. However, the same effect can be obtained even when the position is tilted clockwise.

  In the above embodiment, when the liquid crystal panel 20 is in the transmissive state, the dark color of the surface of the auxiliary light source 60 is observed on the liquid crystal panel 20. Therefore, it is preferable to provide a light absorption layer between the reflective polarizing plate 16 and the auxiliary light source 60. If the light absorption layer is provided, the surface color of the auxiliary light source 60 observed on the liquid crystal panel 20 can be displayed in black.

  Further, when the auxiliary light source 60 is turned on and the liquid crystal panel 20 is in a transmissive state, in order not to attenuate the light B from the auxiliary light source 60, a large number of fine openings may be provided on the surface of the light absorption layer. preferable. If a large number of fine openings are provided on the surface of the light absorption layer, the light B from the auxiliary light source 60 is transmitted through the openings, so that the amount of light observed on the liquid crystal panel 20 is greatly affected. Absent. In addition, a preferable value can be selected for the aperture ratio due to the minute openings in the light absorption layer from the range of 30% to 70%. The fine openings may be in the form of minute round holes or may be formed in a lattice shape, and the openings need not be regularly formed, and may be formed randomly.

  In the present embodiment, a reflection layer that reflects a part of the visible light region may be provided on the light emitting side surface of the auxiliary light source 60. The reflective layer may be a layer that reflects a part of the wavelength in the visible light region and reflects a specific color as the reflected light, reflects a part of the light amount over the entire visible light region, A transflective film that transmits light may be used. For example, when a reflective layer that reflects blue light is provided, the reflected light from the auxiliary light source 60 observed on the liquid crystal panel 20 can be blue when the liquid crystal panel 20 is in a transmissive state. That is, it is possible to change the display color when the liquid crystal panel 20 is in the transmissive state.

  In the above embodiment, the polarity reversal of the ferroelectric liquid crystal 10 is performed by the control unit 21 using the drive voltage waveform control circuit 22, the scan drive voltage waveform generation circuit 23, and the signal drive voltage waveform generation circuit 24, and the display data storage unit. In FIG. 27, the display data for normal display is stored in advance as negative / positive inversion display data that has been negative / positive inversion, and the polarity of the drive waveform applied to the scan electrode or the signal electrode is stored using the stored negative / positive inversion display data. Control was performed so as to reverse the previous drive waveform. However, the polarity inversion of the ferroelectric liquid crystal 10 can be performed by inverting the polarity of the voltage supplied from the power supply unit 25 to the liquid crystal panel 20 in addition to using display data. In that case, the control unit 21 can use any electronic circuit for inverting the polarity.

Note that the transmission axes b ₁ and b ₂ of the reflective polarizing plate in the above example correspond to the first transmission axis in the claims, and the transmission axes a ₁ and a _{2 of} the polarizing plate 15 correspond to the _second transmission axes in the claims. Corresponds to the transmission axis.

It is a block block diagram of the liquid crystal display device which concerns on this invention. It is a figure which shows the structural example of the liquid crystal panel concerning this invention. It is a figure which shows the relationship between the polarizing plate of the liquid crystal panel which concerns on a 1st Example, and a reflection type polarizing plate. The relationship between the applied voltage and light transmittance of the liquid crystal panel according to the first embodiment is shown, (a) shows a case where the auxiliary light source is turned off, and (b) shows a case where the auxiliary light source is turned on. (A) The example of a display at the time of utilizing the liquid crystal panel concerning this invention for a mobile telephone is shown, (b) is a figure which shows the case where a display is reversed. It is a figure which shows an example of the drive voltage waveform applied to a liquid crystal panel. It is a figure which shows the relationship between the polarizing plate of the liquid crystal panel which concerns on a 2nd Example, and a reflection type polarizing plate. The relationship between the applied voltage and the light transmittance of the liquid crystal panel according to the second embodiment is shown, (a) shows the case where the auxiliary light source is turned off, and (b) shows the case where the auxiliary light source is turned on. (A) The example of a display at the time of using the liquid crystal panel concerning this invention for a wristwatch is shown, (b) is a figure which shows the case where a display is reversed.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Ferroelectric liquid crystal 11a, 11b Transparent glass substrate 13a Scan electrode 13b Signal electrode 15 Polarizing plate 16 Reflective polarizing plate 20 Liquid crystal panel 21 Control part 22 Drive signal waveform control circuit 23 Scan drive voltage waveform generation circuit 24 Signal drive voltage waveform generation Circuit 25 Power supply unit 27 Display data storage unit 50 Clock circuit 60 Auxiliary light source 62 Auxiliary light source switch

Claims (5)

A transflective ferroelectric liquid crystal display device,
A first substrate;
A second substrate;
Arranged on the first substrate, each having a first transmission axis and a first reflection axis orthogonal to each other, and transmitting linearly polarized light having a vibration plane parallel to the first transmission axis, and A reflective polarizing plate that reflects linearly polarized light having a vibration plane parallel to the first reflection axis;
Polarized light that is disposed on the second substrate, has a second transmission axis parallel or perpendicular to the first transmission axis, and transmits linearly polarized light having a vibration plane parallel to the second transmission axis. The board,
It is sandwiched between the first and second substrates, maintains either the first stable state or the second stable state, and the alignment direction of the liquid crystal molecules in the first stable state is the second And a ferroelectric property in which the orientation direction of the liquid crystal molecules in the second stable state is inclined to the left from the second transmission axis. A liquid crystal layer;
An auxiliary light source provided on the reflective polarizing plate side,
When the reflective polarizing plate and the polarizing plate are arranged so that the first transmission axis and the second transmission axis are parallel to each other, the first stable light source is turned off when the auxiliary light source is turned off. Controlled to display white in the state and black in the second stable state,
When the reflective polarizing plate and the polarizing plate are arranged so that the first transmission axis and the second transmission axis are perpendicular to each other, the first stable state is obtained when the auxiliary light source is OFF. To display black and white display in the second stable state,
When the auxiliary light source is ON, the first stable state and the second stable state are controlled to be switched.
A transflective ferroelectric liquid crystal display device characterized by that. The reflective polarizing plate and the polarizing plate are arranged so that the first transmission axis and the second transmission axis are parallel to each other when the transmissive display is important, and the first transmission axis. The transflective ferroelectric material according to claim 1, wherein the reflective polarizing plate and the polarizing plate are disposed so that the second transmission axis is perpendicular to the second transmission axis when importance is placed on reflective display. Liquid crystal display device. In addition, an inversion control unit that controls to invert the stable state of the ferroelectric liquid crystal layer from one to the other in response to ON of the auxiliary light source,
A scan electrode disposed on one of the first and second substrates, and a voltage applied to the ferroelectric liquid crystal layer, and disposed on the other of the first and second substrates. A signal electrode for applying a voltage to the ferroelectric liquid crystal layer,
The transflective ferroelectric liquid crystal display device according to claim 1, wherein the inversion control unit performs control so as to invert a polarity of a driving waveform applied to the scan electrode or the signal electrode. And a power supply unit for supplying power to at least the transflective ferroelectric liquid crystal display device,
4. The transflective reflection according to claim 3, wherein the inversion control unit controls the polarity of the voltage generated in the power supply unit to be inverted to invert the stable state of the ferroelectric liquid crystal layer from one to the other. Type ferroelectric liquid crystal display device. Further, the inversion control unit has an arithmetic circuit,
The said inversion control part is controlled so that the stable state of the said ferroelectric liquid crystal layer may be inverted from one side to the other by converting normal display data into inversion display data by the said arithmetic circuit. Transflective ferroelectric liquid crystal display device.

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