JP2007248766A - Liquid crystal display element and method of driving liquid crystal display element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal display element capable of performing high-quality display. <P>SOLUTION: The liquid crystal display element includes a light source, a first polarizing late, a first liquid crystal cell on which light transmitted through the first polarizing plate is incident, a second liquid crystal cell, a second polarizing plate disposed on the second liquid crystal cell on the opposite side from the first polarizing plate, and a control circuit which switches alignment states of the liquid crystal cells. The first liquid crystal cell comprises first and second substrates where first and second areas are defined, a first liquid crystal layer arranged between the first and second substrates, and a reflecting plate which is disposed on the second substrate on the side of the first liquid crystal layer or on the opposite side and reflects light transmitted through the first liquid crystal layer to make the light incident on the first polarizing plate, and can transmit only light projected from one of the first and second areas when the light transmitted through the first polarizing plate travels forward and backward in the first liquid crystal cell and enters the first polarizing plate again. The second liquid crystal cell comprises third and fourth substrates where first and second display units on which light transmitted through the first and second areas is incident are defined, and a second liquid crystal layer disposed between the third and fourth substrates. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a liquid crystal display (LCD) and a driving method thereof.

  FIG. 10 is a schematic exploded perspective view showing an example of the internal configuration of a liquid crystal display element that performs color display.

  The liquid crystal display element is configured to include an upper substrate 50a and a lower substrate 50b disposed to face each other substantially in parallel, and a liquid crystal layer 55 sandwiched therebetween. The upper substrate 50a and the lower substrate 50b are formed of, for example, flat glass substrates (upper and lower glass substrates 51a and 51b) and transparent conductive materials such as ITO (indium tin oxide) on the opposing surfaces thereof, Electrodes having a pattern (upper and lower transparent electrodes 52a and 52b) and alignment films (upper and lower alignment films 53a and 53b) formed so as to cover the electrodes are provided. The liquid crystal layer 55 is a twisted nematic (TN) liquid crystal layer formed of, for example, nematic liquid crystal having positive dielectric anisotropy (Δε> 0), and the upper and lower alignment films 53a and 53b are rubbed. The twist angle determined by the direction is, for example, 90 °. The upper and lower transparent electrodes 52a and 52b overlap with each other with the liquid crystal layer 55 interposed therebetween to define a display portion.

An area color filter 60 and a black mask 59 are arranged between the upper substrate 50a and the liquid crystal layer 55 from the liquid crystal layer 55 side. The area color filter 60 has a red portion 60r, a green portion 60g, a blue portion 60b, and a white portion. Part 60w is comprised. For example, the red portion 60r transmits light in the red wavelength region.

  The black mask 59 is arranged to cover the boundary of the color region and shield it from light and to improve contrast and color purity.

  A pair of upper and lower polarizing plates 54a and 54b are disposed outside the upper substrate 50a and the lower substrate 50b. The upper and lower polarizing plates 54a and 54b each have a transmission axis in the in-plane direction, and transmit only light polarized in the direction of the transmission axis. Both are arranged in a crossed Nicols state along the rubbing direction. In this figure, the direction of the transmission axis is indicated by an arrow.

  A white backlight 57 is disposed outside the lower polarizing plate 54b. The white backlight 57 is configured using, for example, a cold cathode fluorescent lamp (CCFL), and emits white light. In some cases, an inorganic white LED (light emitting diode), an organic white LED, or the like is used.

  The light emitted from the white backlight 57 and incident on the lower polarizing plate 54 b becomes light having a polarization direction in the transmission axis direction of the lower polarizing plate 54 b and enters the liquid crystal layer 55.

  In a state where no voltage is applied to the upper and lower transparent electrodes 52a and 52b, the polarization direction of the incident light is rotated by 90 ° according to the orientation of the liquid crystal molecules, so that the light transmitted through the upper polarizing plate 54a arranged in the crossed Nicols state, Normally-on display is performed.

  In the illustrated liquid crystal display element, light emitted from the white backlight 57 passes through different color regions (each color portion 60r, g, b, w) of the area color filter 60 to become colored light, which is transmitted. Different colors can be displayed for each area.

  In a state where a voltage is applied to the upper and lower transparent electrodes 52a and 52b, the liquid crystal molecules of the liquid crystal layer 55 rise substantially perpendicular to the upper and lower substrates 54a and 54b, and the light incident on the liquid crystal layer 55 is polarized. The liquid crystal layer 55 is emitted without changing the direction. For this reason, black display is performed by being blocked by the upper polarizing plate 54a arranged in the crossed Nicols arrangement.

  Using the structure shown in this figure, segment display and dot display are possible. In addition, the color used for the area color filter 60 can be displayed in a plurality of colors.

  However, in a certain display segment or dot, only a specific color (color of the color portion of the area color filter 60 corresponding to the segment or dot) and black can be displayed.

  As a display element that solves this drawback, a micro color filter type liquid crystal display element is known. The micro color filter method is employed particularly in a full-dot type liquid crystal display element, and fine dots are color-coded into red (R), green (G), and blue (B), and color display is performed using 3 dots as one pixel. It is a display method.

  However, when the display segment or dot is large, the viewer may recognize that one pixel is divided, and the display quality may deteriorate. Further, since one pixel is composed of a plurality of dots, the light use efficiency is lowered, and as a result, it is necessary to improve the luminance of the light (light source), and the power consumption increases.

  For example, in a liquid crystal display element that performs segment display, a field sequential (FS) driving method is well known as a method of independently changing the color of a display area in units of segments.

  FIG. 11A is a schematic exploded perspective view showing an internal configuration example of a liquid crystal display element capable of performing FS driving, and FIG. 11B is a plan view showing a display portion of the liquid crystal display element. It is.

  Reference is made to FIG. 10 differs from the liquid crystal display element shown in FIG. 10 in that a multi-color backlight 56 is used in place of the white backlight 57, and the area color filter 60 is provided between the upper substrate 50a and the liquid crystal layer 55. The black mask 59 is not disposed, and the backlight synchronous drive circuit 75 is added.

  The multi-color backlight 56 is a backlight that can emit light of a plurality of colors, and includes, for example, an RGB multi-color LED light source. In the FS drive, the multi-color backlight 56 repeats time-division light emission in the order of red (R), green (G), and blue (B), for example. The backlight synchronous drive circuit 75 is connected, for example, between the multi-color backlight 56 and the upper and lower transparent electrodes 52a and 52b, and switches the liquid crystal cells (light) in synchronization with the light emission timing of the multi-color backlight 56. On / off).

  In the FS drive method, display is performed by separating image data into R, G, and B color data, and combining (additive color mixing) these on the time axis. By switching the light emission of the multi-color backlight 56 at such a high speed that it cannot be decomposed by the human eye, the mixed color image is recognized by the human eye.

  Reference is made to FIG. The liquid crystal display element is displayed on, for example, a 7-segment display unit 30. The display unit 30 includes display units (each segment) 31 to 37 and a background region 38. Each of the display units 31 to 37 is provided with electrodes that can be driven independently. By selectively applying a voltage to these electrodes, the alignment state of the liquid crystal molecules in the liquid crystal layer corresponding to the electrodes can be changed, and for example, numbers “0” to “9” can be displayed.

  In this specification, for example, a display unit used for displaying numbers is called a display area, and other display units and background areas are called non-display areas. For example, when the number “7” is displayed, the display area means display units 31 to 33, and the non-display area means display units 34 to 37 and the background area 38.

  FIG. 12 is a timing chart showing an example of display control in the liquid crystal display element using the FS driving method. With reference to FIG. 12, an FS liquid crystal driving method will be described.

  In the FS driving method, as described above, the multi-color backlight repeats time division light emission in the order of R, G, and B, for example. A period in which each of R, G, and B emits light sequentially once is called one frame. One frame is 16.7 ms, for example. One image is displayed for each frame. In order to additively mix R, G, and B light, it is desirable that one frame is, for example, 20 ms or less (frame frequency is 50 Hz or more).

  One frame is divided into a plurality of (three) sub-frames (SF). 1SF is, for example, 5.57 ms.

  Refer to the “Multi-color backlight” stage. One SF is divided into a light emission period and a blank period. During the light emission period of each SF (SF1 to SF3), any one of R, G, and B is emitted. In the timing chart shown in FIG. 12, light emission of R, G, and B is performed in each light emission period of SF1, SF2, and SF3.

  In the liquid crystal display element, the time required for the response of the liquid crystal layer to the applied voltage is longer than the time required for switching the emission color of the multicolor backlight. The blank period is a period in which no light of any color is emitted, and is a time necessary for the liquid crystal molecules of the liquid crystal layer to substantially change the alignment state by the applied voltage.

  Reference is made to the column “Display Unit 31”. The notation such as “display unit 31” and “display unit 32” used below represents each display unit shown in FIG. In this figure, “ON” in the display unit stage of the drive timing chart indicates that the display unit is in a state of transmitting light, and “OFF” indicates that the display unit is in a state of not transmitting light. Indicates.

  The display unit 31 transmits light in SF1 and SF2. Therefore, yellow (Y), which is a mixed color of R and G, is recognized by the observer.

  Reference is made to the column “Display Unit 32”. The display unit 32 transmits light in SF1 and SF3. Therefore, the observer recognizes magenta (M), which is a mixed color of R and B.

  Reference is made to the column “Display Unit 37”. The display unit 37 transmits light in SF2. Therefore, green (G) is recognized by the observer.

  However, when the line of sight is deviated from the display portion obtained by additive color mixing of two or more colors, or when the liquid crystal display element is vibrated, the images of the SFs that are not normally recognized by the observer's eyes are separated. The phenomenon observed in this way, the so-called color break phenomenon, may occur. The color break phenomenon is noticeable when the surroundings are dark. The occurrence of the color break phenomenon is not preferable because of the influence on the psychology of the observer.

Therefore, the inventors of the present invention prevent a color break phenomenon by forming a light of a desired color for each SF and causing it to emit light, and setting a display unit that is in a light-transmitting state in one SF to a light-blocking state in another SF. The liquid crystal display element driving method (the driving method is also included in the FS driving method) has been proposed. (For example, see Patent Document 1.)
FIG. 13 is a timing chart for explaining the driving method of the liquid crystal display element according to the previous proposal.

  Refer to the “Multi-color backlight” stage. In one frame shown in the figure, in SF1, white light is emitted by simultaneous lighting of a plurality of light sources, orange light in SF2, and blue light by single light source emission in SF3. In this figure, the blank period is set to 3 ms in the 1SF period of 5.57 ms.

  Reference is made to the column “Display Unit 31”. In the display unit 31, only SF1 is in a translucent state. Therefore, white display is performed.

  Reference is made to the column “Display Unit 32”. In the display unit 32, all the SFs are light-shielded. Therefore, the display color is black.

  Reference is made to the column “Display Unit 37”. In the display unit 37, only SF2 is in a translucent state. Therefore, an orange display is performed.

  According to the driving method of the liquid crystal display element described in Patent Document 1, the color break phenomenon is prevented and the lighting color of the multi-color backlight can be changed for each frame, so that various color displays are possible. is there.

JP-A-2005-070440

  An object of the present invention is to provide a liquid crystal display element capable of high quality display.

  Another object of the present invention is to provide a liquid crystal display element capable of color display with a plurality of colors.

  It is another object of the present invention to provide a method for driving a liquid crystal display element capable of high quality display.

  It is another object of the present invention to provide a driving method of a liquid crystal display element capable of color display with a plurality of colors.

  According to one aspect of the present invention, a plate-like light source that emits light, a first polarizing plate on which light emitted from the light source enters, and a first light on which light transmitted through the first polarizing plate enters. (I) a first substrate provided with a first electrode having a predetermined shape; and (ii) substantially parallel to the first substrate and on the opposite side to the first polarizing plate. A second substrate provided with a second electrode having a predetermined shape and disposed at a position where the first electrode and the second electrode are opposed to each other; A second substrate having an area defined; (iii) disposed between the first substrate and the second substrate and applying a voltage between the first electrode and the second electrode A first liquid crystal layer whose orientation state can be switched, and (iV) the first liquid crystal layer side of the second substrate, or the first liquid. Disposed on the opposite side of the layer, the light transmitted through the first liquid crystal layer is reflected, emitted from the first liquid crystal cell, and incident on the first polarizing plate to transmit at least a part thereof. When the light transmitted through the first polarizing plate reciprocates through the first liquid crystal cell and enters the first polarizing plate again according to the alignment state, the first area, A first liquid crystal cell capable of preventing light emitted from one of the second areas from passing through the first polarizing plate and preventing light emitted from the other from passing through the first polarizing plate. A second liquid crystal cell on which light reflected by the reflector and transmitted through the first polarizing plate is incident, (i) a third substrate including a third electrode having a predetermined shape; (Ii) a fourth substrate provided with a fourth electrode having a predetermined shape and disposed substantially parallel to the third substrate; The first display unit in which the light transmitted through the first area enters the position where the third electrode and the fourth electrode face each other, and the light transmitted through the second area A fourth substrate in which a second display unit on which light is incident is defined; and (iii) the third electrode and the fourth electrode disposed between the third substrate and the fourth substrate. The second liquid crystal cell comprising a second liquid crystal layer whose orientation state can be switched by applying a voltage between the first liquid crystal cell and the first polarizing plate of the second liquid crystal cell is opposite to the first polarizing plate The second polarizing plate disposed on the side and receiving the light transmitted through the second liquid crystal cell and the period for displaying one image as one frame, one frame is time-divided into a plurality of sub-frames. The first light source is caused to emit light in each subframe and synchronized with the light emission of the first light source. There is provided a liquid crystal display element having a control circuit capable of switching the alignment state of the liquid crystal cell.

  According to another aspect of the present invention, a plate-like light source that emits light, a first polarizing plate on which light emitted from the light source is incident, and light that has passed through the first polarizing plate is incident. (I) a first substrate provided with a first electrode having a predetermined shape, and (ii) the first polarizing plate substantially parallel to the first substrate. A second substrate provided with a second electrode of a predetermined shape disposed on the opposite side, wherein the first area and the second electrode are opposed to each other at the first area, and A second substrate having a second area defined; and (iii) disposed between the first substrate and the second substrate, and between the first electrode and the second electrode. A first liquid crystal layer capable of switching an alignment state by applying a voltage; and (iV) the first liquid crystal layer side of the second substrate; or 1 disposed on the opposite side of the first liquid crystal layer, the light transmitted through the first liquid crystal layer is reflected, emitted from the first liquid crystal cell, incident on the first polarizing plate, and at least a part thereof When the light transmitted through the first polarizing plate reciprocates through the first liquid crystal cell and is incident on the first polarizing plate again, the first polarizing plate according to the alignment state. The light that has exited one of the second area and the second area can be transmitted through the first polarizing plate, and the light that has exited the other can be prevented from passing through the first polarizing plate. A liquid crystal cell, and a second liquid crystal cell on which light reflected by the reflecting plate and transmitted through the first polarizing plate is incident, and (i) a third liquid crystal cell having a third electrode having a predetermined shape A substrate, and (ii) a fourth electrode having a predetermined shape and disposed substantially parallel to the third substrate. A first display unit in which light transmitted through the first area is incident at a position where the third electrode and the fourth electrode face each other, and the second area A fourth substrate in which a second display unit on which transmitted light is incident is defined; (iii) disposed between the third substrate and the fourth substrate; and the third electrode and the fourth substrate A second liquid crystal cell including a second liquid crystal layer whose orientation state can be switched by applying a voltage between the first and second electrodes, and the first polarizing plate of the second liquid crystal cell. The second polarizing plate is disposed on the opposite side of the first liquid crystal cell, and the light passing through the second liquid crystal cell is incident thereon. When one image is displayed for one frame, one frame is divided into a plurality of sub-frames. Time-dividing, causing the light source to emit light in each subframe, and synchronizing with the light emission of the light source, A method of driving a liquid crystal display element having a control circuit capable of switching an alignment state of the first liquid crystal cell, wherein a display is performed with light emitted from the first area in a subframe. Displaying in the other sub-frame with the light emitted from the second area, and each of the first and second display units is displayed in at most one sub-frame in one frame. A method for driving a liquid crystal display element is provided.

  ADVANTAGE OF THE INVENTION According to this invention, the liquid crystal display element in which a high quality display is possible can be provided.

  In addition, it is possible to provide a liquid crystal display element capable of color display with a plurality of colors.

  Furthermore, it is possible to provide a method for driving a liquid crystal display element capable of high-quality display.

  In addition, it is possible to provide a method for driving a liquid crystal display element capable of color display with a plurality of colors.

  The inventors of the present application have proposed a liquid crystal display device having a novel structure and a display method thereof in Japanese Patent Application No. 2004-118870 (Japanese Patent Application No. 2004-118870, Disclosure of Invention [0010] to [0042]). .

  A liquid crystal display device according to Japanese Patent Application No. 2004-118870 will be briefly described with reference to FIGS.

  FIG. 1A illustrates a display portion of a liquid crystal display device. The display unit includes, for example, three segment units (“STANLEY R & D” and left and right seven segment units). According to the liquid crystal display device, it is possible to change the color tone for each segment portion, for example. For example, “5” can be displayed in red in the left seven segment portion, “7” in yellow in the right seven segment portion, and “STANLEY R & D” in blue. In this figure, the area displayed in red, yellow, or blue is indicated by hatching.

  FIG. 1B is a schematic exploded perspective view showing an example of the internal configuration of the liquid crystal display device.

  The liquid crystal display device shown in the figure includes a display liquid crystal cell 76 and an area dividing liquid crystal cell 77. Both the cells 76 and 77 are arranged in alignment with the display liquid crystal cell 76 on the upper side and the area dividing liquid crystal cell 77 on the lower side.

  Both the cells 76 and 77 are configured to include an upper substrate 50a and a lower substrate 50b disposed to face each other substantially in parallel, and a liquid crystal layer 55 sandwiched therebetween.

  For both of the cells 76 and 77, the upper substrate 50a and the lower substrate 50b are formed of, for example, flat glass substrates (upper and lower glass substrates 51a and 51b) and transparent conductive materials such as ITO on the opposing surfaces thereof. , Electrodes (upper and lower transparent electrodes 52a and 52b) having a predetermined pattern, and alignment films (upper and lower alignment films 53a and 53b) formed so as to cover the respective electrodes.

  The liquid crystal layer 55 is a TN liquid crystal layer formed of, for example, a nematic liquid crystal having a positive dielectric anisotropy (Δε> 0), and a twist angle determined by the rubbing directions of the upper and lower alignment films 53a and 53b. Is, for example, 90 °.

  Between the upper transparent electrode 52a and the lower transparent electrode 52b, a voltage applying means 68 capable of applying an arbitrary voltage is connected between the electrodes 52a and 52b. The alignment state of the liquid crystal molecules of the liquid crystal layer 55 between the electrodes 52a and 52b can be changed by the voltage applied between the electrodes 52a and 52b by the voltage applying means 68.

  When no voltage is applied, the light incident on the cells 76 and 77 is emitted from the cells 76 and 77 by changing the polarization direction by 90 ° in the liquid crystal layer 55. When a voltage is applied, the light incident on the cells 76 and 77 exits the cells 76 and 77 without changing the polarization direction.

  The liquid crystal cell 76 for display and the liquid crystal cell 77 for area division differ in the shape of an electrode. The electrode of the display liquid crystal cell 76 has a shape corresponding to the shape of the segment portion shown in FIG. The electrodes of the area dividing liquid crystal cell 77 will be described with reference to the next figure.

  The upper polarizing plate 54 a is disposed outside the upper substrate 50 a of the display liquid crystal cell 76, the lower polarizing plate 54 b is disposed outside the lower substrate 50 b of the area dividing liquid crystal cell 77, and between the cells 76 and 77. Central polarizing plates 54i are arranged parallel to each other. These polarizing plates 54a, 54b, 54i each have a transmission axis in the in-plane direction, and transmit only light polarized in the direction of the transmission axis. In the figure, the direction of the transmission axis is indicated by an arrow. The transmission axis directions of the polarizing plates 54a, 54b, and 54i are parallel to each other.

  A multi-color backlight 56 is disposed outside the lower polarizing plate 54b. The multi-color backlight 56 is a light that can selectively emit light of a plurality of colors, and has, for example, an RGB multi-color LED light source on the side, and irradiates incident light toward the liquid crystal layer. . As the color light source, an organic LED, an inorganic LED, a CCFL, an FE lamp, or the like can be used. The change of the emitted light color may be realized by a configuration using a plurality of monochromatic light sources having different emission colors, or may be realized by a configuration using a single light source capable of changing the emission color.

  A synchronizing circuit 78 is connected between the multi-color backlight 56 and the voltage applying means 68 of the display liquid crystal cell 76 and the area dividing liquid crystal cell 77. The synchronizing circuit 78 turns on / off the multi-color backlight 56 and applies a voltage to both electrodes 52a and 52b of the display liquid crystal cell 76 and the area dividing liquid crystal cell 77 (change in the alignment state of the liquid crystal molecules in the liquid crystal layer 55). ) Can be synchronized.

  With reference to FIGS. 1C to 1E, the operation of the liquid crystal display device shown in FIG. 1B will be described. For example, driving is performed using an FS driving method in which one frame is divided into three SFs of SF1 to SF3.

  The multi-color backlight 56 emits red light in SF1, blue light in SF2, and yellow light in SF3. The emitted light becomes polarized light having a polarization direction in the transmission axis direction of the lower polarizing plate 54 b and enters the area dividing liquid crystal cell 77.

  The area dividing liquid crystal cell 77 has a predetermined area (in FIG. 1C to FIG. 1E, the area 81 is defined as the incident light from the multi-color backlight 56 is defined on the upper substrate 50a side by the shape of the electrode. The three areas (˜83) can be divided and emitted. That is, the electrode shape of the area dividing liquid crystal cell 77 is formed corresponding to the shape of the areas 81 to 83.

  Areas 81 and 82 are areas corresponding to the left and right seven-segment portions shown in FIG. The numbers “0” to “9” can be displayed by the light emitted from the areas 81 and 82, respectively.

  The area 83 is an area corresponding to the character string “STANLEY R & D” in the segment portion shown in FIG. 1A, and the character string can be displayed by the light emitted from the area 83.

  In the display liquid crystal cell 76, a voltage is applied to predetermined electrodes through SF1 to SF3. In the left 7-segment part, a voltage is applied to the electrodes corresponding to the display units 31, 33, 34, 36, and 37 that display “5”. In the right 7-segment part, a voltage is applied to the electrodes corresponding to the display units 31 to 33 displaying “7”. Further, a voltage is applied to the electrode corresponding to the character string “STANLEY R & D”.

  Reference is made to FIG. In SF1, a voltage is applied between the electrodes 52a and 52b corresponding to the area 81 of the area dividing liquid crystal cell 77. For this reason, of the red light emitted from the multi-color backlight 56, only the light emitted from the area 81 is transmitted through the central polarizing plate 54i while maintaining the polarization state defined by the lower polarizing plate 54b.

  Corresponds to the electrodes 52a and 52b that define the display units 31, 33, 34, 36, and 37 that display “5” in the left seven segment portion of the display liquid crystal cell 76 out of the light transmitted through the central polarizing plate 54i. Only the light transmitted through the liquid crystal layer 55 (red light displaying the character “5”) passes through the upper polarizing plate 54a in the polarization state as it is and reaches the eyes of the observer.

  Reference is made to FIG. In SF2, blue light is emitted from the multi-color backlight 56 as described above. In addition, a voltage is applied between the electrodes 52 a and 52 b corresponding to the area 82 of the area dividing liquid crystal cell 77. In the display liquid crystal cell 76, a voltage is applied to the electrodes corresponding to the display units 31 to 33 that display “7” in the right seven segment portion.

  For this reason, only the blue light that displays the character “7” in the right seven-segment portion passes through the upper polarizing plate 54a and reaches the eyes of the observer.

  Reference is made to FIG. In SF3, yellow light is emitted from the multi-color backlight 56 as described above. A voltage is applied between the electrodes 52 a and 52 b corresponding to the area 83 of the area dividing liquid crystal cell 77. In the display liquid crystal cell 76, a voltage is applied between the electrodes 52a and 52b that display the character string “STANLEY R & D”. Therefore, only the yellow light that displays the character “STANLEY R & D” is the upper polarizing plate 54a. To reach the observer's eyes.

  Thus, when the liquid crystal display device according to Japanese Patent Application No. 2004-118870 is used, the color tone can be changed for each segment portion, for example.

  FIG. 2 is a schematic exploded perspective view showing an example of the internal configuration of the liquid crystal display device according to the embodiment.

  The liquid crystal display element according to the embodiment includes a display liquid crystal cell 76 and an area dividing liquid crystal cell 77 having the same configuration as the cell used in the liquid crystal display device shown in FIG. In the liquid crystal display device shown in FIG. 1B, when no voltage is applied, the light incident on the area dividing liquid crystal cell 77 is changed in the polarization direction by 90 ° by the liquid crystal layer 55 and is emitted from the cell 77. As described above, the retardation of the liquid crystal layer 55 of the area dividing liquid crystal cell 77 is determined. However, in the liquid crystal display element according to the embodiment, for example, when light incident upon no voltage application passes through the liquid crystal layer 55 twice, the polarization direction The retardation of the liquid crystal layer 55 is determined so as to change by 90 ° (for example, the x component is delayed by a half wavelength).

  An upper polarizing plate 54 a is disposed outside the upper substrate 50 a of the display liquid crystal cell 76, and a reflector 67 that reflects incident light is disposed outside the lower substrate 50 b of the area dividing liquid crystal cell 77. The The reflector 67 is made of metal, for example. The reflection plate 67 may have a mirror surface, or may have a scattering reflection surface subjected to anti-glare processing, for example. Further, the reflection plate 67 can be arranged inside instead of being arranged outside the lower glass substrate 51 b of the area dividing liquid crystal cell 77.

  Between the lower substrate 50b of the display liquid crystal cell 76 and the upper substrate 50a of the area dividing liquid crystal cell 77, a multi-color light 66, a central polarizing plate 54i, and a quarter wavelength plate 69 are arranged in this order. They are arranged in alignment from the cell 76 side.

  The multi-color light 66 is, for example, a plate-like light source, and can irradiate light toward the area dividing liquid crystal cell 77. The quarter-wave plate 69 is composed of, for example, a combination of a half-wave plate and a quarter-wave plate, and emits a quarter wavelength delayed phase to the x component of incident light. The central polarizer 54i and the quarter wavelength plate 69 constitute a circular polarizer.

  In the figure, the transmission axis direction of the polarizing plates 54a and 54i and the slow axis direction of the quarter wavelength plate 69 are indicated by arrows. The polarizing plates 54a and 54i are arranged, for example, in parallel Nicols, and the display liquid crystal cell 76 (not considering the multi-color light 66, the upper polarizing plate 54a, the upper substrate 50a, the liquid crystal layer 55, the lower substrate 50b, and the center). The portion constituted by the polarizing plate 54i constitutes a normally-off type element. The angle formed by the slow axis direction of the quarter-wave plate 69 and the transmission axis direction of the central polarizing plate 54i is, for example, 45 °.

  In the embodiment, one polarizing plate is inserted between the lower substrate 50b of the display liquid crystal cell 76 and the upper substrate 50a of the area dividing liquid crystal cell 77 (central polarizing plate 54i). It is also possible to adopt a configuration in which one sheet is inserted into each of the liquid crystal cell 76 side and the area dividing liquid crystal cell 77 side. Further, it is desirable that the display liquid crystal cell 76 be black in the non-display area in consideration of the appearance of the display when the external light is incident. In this regard, in the embodiment, the display liquid crystal cell 76 is a normally-off type element, but may be realized as a configuration including a black mask that shields the entire background region.

  In addition, the liquid crystal element part comprised by the center polarizing plate 54i, the quarter wavelength plate 69, the area division | segmentation liquid crystal cell 77, and the reflecting plate 67 is normally on.

  A synchronizing circuit 78 is connected between the multi-color light 66 and the voltage applying means 68 of the display liquid crystal cell 76 and the area dividing liquid crystal cell 77. The synchronization circuit 78 time-divides one frame into a plurality of SFs, turns on / off the multi-color light 66 within each SF, and applies voltages to both electrodes 52a and 52b of the display liquid crystal cell 76 and the area division liquid crystal cell 77. (Change in the alignment state of the liquid crystal molecules in the liquid crystal layer 55) can be synchronized. Further, the multi-color light 66 can be controlled to emit light of different colors in all SFs in one frame.

  In the embodiment shown in FIG. 2, the liquid crystal element portion composed of the central polarizing plate 54i, the quarter-wave plate 69, the area dividing liquid crystal cell 77, and the reflecting plate 67 has a TN type normally-on configuration. However, for example, between the quarter-wave plate 69 and the area dividing liquid crystal cell 77, the liquid crystal twist direction is opposite to that of the area dividing liquid crystal cell 77, and the alignment direction of the central molecule in the thickness direction of the liquid crystal layer is A liquid crystal cell orthogonal to that of the area dividing liquid crystal cell 77 may be inserted to form a normally-off configuration. Instead of the liquid crystal cell, an optical film having an equivalent function, for example, Twistar manufactured by Polatechno Co., Ltd. can be used.

  Alternatively, the area dividing liquid crystal cell 77 may be formed of a negative type liquid crystal material to be a vertical alignment type.

  Hereinafter, the operation of the liquid crystal display device according to the embodiment will be described. 1A is defined on the light emission surface of the display liquid crystal cell 76 (for example, the surface of the upper substrate 50a of the display liquid crystal cell 76), and the light emission of the area dividing liquid crystal cell 77 is defined. Areas 81 to 83 shown in FIG. 1C are defined on the surface (for example, the surface on the quarter-wave plate 69 side of the upper substrate 50a of the area dividing liquid crystal cell 77). "Is displayed in red," 7 "is displayed in blue, and" STANLEY R & D "is displayed in yellow. The liquid crystal display element is driven using, for example, an FS driving method in which one frame is divided into three SFs of SF1 to SF3.

  The multi-color light 66 emits red light in SF1, blue in SF2, and yellow in SF3 toward the area dividing liquid crystal cell 77. The emitted light first passes through the central polarizing plate 54i, becomes polarized light having a polarization direction in the transmission axis direction of the central polarizing plate 54i, and enters the quarter-wave plate 69, and is ¼ in the x component. In response to the slow phase of the wavelength, the light enters the area dividing liquid crystal cell 77.

  Light incident on and transmitted through the area dividing liquid crystal cell 77 is reflected by the reflector 67 and reenters the area dividing liquid crystal cell 77 from the lower substrate 50b side. The light transmitted through the area dividing liquid crystal cell 77 enters the quarter-wave plate 69 from the lower side.

  In the area dividing liquid crystal cell 77, a voltage is applied between the electrodes 52a and 52b corresponding to the areas 82 and 83 in SF1. For this reason, only the liquid crystal molecules in the portion of the liquid crystal layer 55 corresponding to the areas 82 and 83 are aligned substantially perpendicular to the upper and lower substrates 50a, 50b, and that corresponding to the other portions (including the area 81) is aligned. Does not change state. Therefore, in the process of being transmitted through the area dividing liquid crystal cell 77, reflected by the reflector 67, and retransmitted through the area dividing liquid crystal cell 77, light emitted from portions other than the areas 82 and 83 (light emitted from the area 81). Is subjected to a ½ wavelength delayed phase by the liquid crystal layer 55. Further, the light emitted from the areas 82 and 83 is not changed in the polarization state.

  The light emitted from the upper substrate 50a of the area dividing liquid crystal cell 77 (including the light emitted from the areas 81 to 83) is uniformly delayed by a quarter wavelength plate 69 with a quarter wavelength in the x component. Receive.

  As described above, after exiting the central polarizing plate 54i, the light is reflected by the reflection plate 67, and is incident on the portion other than the areas 82 and 83 (including the area 81) before being incident on the central polarizing plate 54i again. The received light undergoes a slow phase corresponding to a total of one wavelength in the x component. In addition, the light that enters and exits the areas 82 and 83 is subjected to a slow phase corresponding to a total of ½ wavelength in the x component.

  Therefore, the light that enters and exits the part other than the areas 82 and 83 (including the area 81) passes through the central polarizing plate 54i and the multi-color light 66 from the lower side, and below the display liquid crystal cell 76. The light enters the side substrate 50b. Light entering and exiting the areas 82 and 83 is blocked by the central polarizing plate 54i.

  In the display liquid crystal cell 76, a voltage is applied to predetermined electrodes through SF1 to SF3. In the left 7-segment part, a voltage is applied to the electrodes corresponding to the display units 31, 33, 34, 36, and 37 that display “5”. In the right 7-segment part, a voltage is applied to the electrodes corresponding to the display units 31 to 33 displaying “7”. Further, a voltage is applied to the electrode corresponding to the character string “STANLEY R & D”.

  In the display liquid crystal cell 76, only the liquid crystal molecules in the liquid crystal layer 55 corresponding to the electrode to which the voltage is applied are aligned substantially perpendicularly to the upper and lower substrates 50a and 50b, so that “5”, “7”, Only the light incident on the position corresponding to “STANLEY R & D” exits the upper substrate 50a in the polarization state equal to that at the time of incidence, passes through the upper polarizing plate 54a, and reaches the eyes of the observer.

  In SF1, only the light emitted from the portions other than the areas 82 and 83 (including the area 81) is incident on the lower substrate 50b of the display liquid crystal cell 76, and is incident on the position corresponding to “5”. Only the transmitted light passes through the upper polarizing plate 54a. Therefore, the light representing “5” reaches the eyes of the observer.

  In SF2, a voltage is applied between the electrodes 52a and 52b corresponding to the areas 81 and 83 of the area dividing liquid crystal cell 77. For this reason, as in the case of SF1, after exiting the central polarizing plate 54i, it is reflected by the reflecting plate 67 and is incident on the central polarizing plate 54i again (including the area 82). ), And the emitted light is subjected to a slow phase of a total of one wavelength in the x component. In addition, the light that enters and exits the areas 81 and 83 is subjected to a slow phase corresponding to a total of ½ wavelength in the x component.

  Therefore, the light that enters and exits the portion other than the areas 81 and 83 (including the area 82) passes through the central polarizing plate 54i and the multi-color light 66 from the lower side, and below the display liquid crystal cell 76. The light enters the side substrate 50b. Light entering and exiting the areas 81 and 83 is blocked by the central polarizing plate 54i.

  Therefore, in SF2, only the light incident on the position corresponding to “7” among the light emitted from the portions other than the areas 81 and 83 (including the area 82) is transmitted through the upper polarizing plate 54a. For this reason, the light representing “7” reaches the eyes of the observer.

  In SF3, a voltage is applied between the electrodes 52a and 52b corresponding to the areas 81 and 82 of the area dividing liquid crystal cell 77. For this reason, as in the case of SF1, after exiting the central polarizing plate 54i, it is reflected by the reflecting plate 67 and is incident on the central polarizing plate 54i again (including the area 83). ), And the emitted light is subjected to a slow phase of a total of one wavelength in the x component. In addition, the light that enters and exits the areas 81 and 82 is subjected to a slow phase corresponding to a total of ½ wavelength in the x component.

  Therefore, the light that enters and exits the portion other than the areas 81 and 82 (including the area 83) passes through the central polarizing plate 54i and the multi-color light 66 from the lower side, and below the display liquid crystal cell 76. The light enters the side substrate 50b. Light entering and exiting the areas 81 and 82 is blocked by the central polarizing plate 54i.

  Therefore, in SF3, only the light incident on the position corresponding to “STANLEY R & D” among the light emitted from the portions other than the areas 81 and 82 (including the area 83) is transmitted through the upper polarizing plate 54a. For this reason, the light representing “STANLEY R & D” reaches the eyes of the observer.

  Through the above operation, the observer can visually recognize red “5”, blue “7”, and yellow “STANLEY R & D”.

  As can be understood from the above description of the operation, it is not always necessary to use a liquid crystal cell that responds quickly to light emission as the display liquid crystal cell 76. Therefore, for example, since a dot display cell driven by a simple matrix can be employed, the manufacturing cost can be reduced.

  On the other hand, since the area dividing liquid crystal cell 77 is required to have a high-speed response, it is preferable that the area dividing liquid crystal cell 77 be driven with a low duty, particularly with a static drive. The area dividing liquid crystal cell 77 is easy to be a static driving cell because the electrode configuration is not fine compared to the display liquid crystal cell 76.

  As described above, the area dividing liquid crystal cell 77 and the multi-color light 66 are synchronized, for example, for each SF, whereas the display liquid crystal cell 76 and the multi-color light 66 are, for example, changed in display. Synchronize with.

  Reference is made to FIGS. 3A and 3B. In the following, through the simulation, the liquid crystal display element according to the embodiment will be considered in more detail, and the effects produced will be mentioned.

  FIG. 3A shows a liquid crystal display element according to an example used for the simulation. In the element shown in FIG. 2, the quarter wavelength plate 69 is composed of a half wavelength plate 69a and a quarter wavelength plate 69b. The half-wave plate 69a and the quarter-wave plate 69b are arranged so that the slow axis is located at a position of 75 ° and 15 ° counterclockwise with respect to the transmission axis of the central polarizing plate 54i, respectively. . Moreover, both the half-wave plate 69a and the quarter-wave plate 69b were assumed to be made of polycarbonate. Note that the liquid crystal display element shown in this figure is a reflective liquid crystal display element including the reflection plate 67 as described above.

  FIG. 3B shows a liquid crystal display element according to a comparative example. The liquid crystal display element according to the comparative example is a transmissive liquid crystal display element. The liquid crystal display element shown in FIG. 1B is arranged in the order of the area dividing liquid crystal cell 77 and the display liquid crystal cell 76 from the multi-color backlight 56 side, and the display is from the upper substrate 50a of the display liquid crystal cell 76. In contrast, the liquid crystal display element according to the comparative example is arranged in the order of the liquid crystal cell for display 76 and the liquid crystal cell for area division 77 from the multicolor front light 70 side, and the display is performed for the liquid crystal for area division. This is performed with light extracted from the lower substrate 50 b of the cell 77. In the liquid crystal display element shown in FIG. 1B, the polarizing plates are arranged in parallel Nicols for both the area dividing liquid crystal cell 77 and the display liquid crystal cell 76. However, in the liquid crystal display element according to the comparative example, Is different from the liquid crystal cell 77 for area division in that the polarizing plates are arranged in crossed Nicols. The liquid crystal cell for area division was changed to normally white to have the same optical configuration as the proposed reflective type. The alignment direction of the liquid crystal molecules located in the center of the thickness direction of the liquid crystal layer 55 of the area dividing liquid crystal cell 77 is the transmission axis direction of the central polarizing plate 54i and the transmission axis direction of the lower polarizing plate 54b. Each is at 45 °.

  As a polarizing plate used in the liquid crystal display element according to the example shown in FIG. 3A and the liquid crystal display element according to the comparative example shown in FIG. 3B, SHC125U manufactured by Polatechno Co., Ltd. was assumed. In addition, the liquid crystal layer 55 of the area dividing liquid crystal cell 77 of both liquid crystal display elements is configured using a positive type liquid crystal having a dielectric anisotropy Δε = 5.1. The liquid crystal molecular alignment in the liquid crystal layer 55 was horizontal TN alignment, and the pretilt angles of the upper and lower substrates 50a and 50b were 1 °. The ratio between the liquid crystal layer 55 thickness d and the chiral pitch p in the liquid crystal layer 55 was set to 0.1. The twist direction was set counterclockwise.

  This inventor analyzed about the Example and comparative example which are shown to FIG. 3 (A) and (B) using the simulator "LCD MASTER 6" made from Shintech. In performing the simulation, the twist angle of the area dividing liquid crystal cell 77 was changed in a range of 60 ° to 110 °.

  4A to 4C show the analysis results of the area dividing liquid crystal cell 77 of the example and the comparative example.

  Reference is made to FIG. When the twist angle of the area-dividing liquid crystal cell 77 is changed, the inventor of the present application reflects the reflective plate 67 for the example, and the maximum reflectance of the light reaching the polarizing plate 54i, for the comparative example, The thickness d of the liquid crystal layer 55 of the area dividing liquid crystal cell 77 giving the maximum transmittance (hereinafter referred to as maximum reflectance / maximum transmittance) in the lower polarizing plate 54b was obtained. FIG. 4A shows the twist angle dependence of the product (retardation Δnd) of the liquid crystal layer 55 thickness d and the birefringence Δn of the liquid crystal material.

  The horizontal axis of the graph indicates the twist angle in the unit “° (degrees)”. The vertical axis indicates retardation Δnd in the unit “μm”. Curve a shows the relationship between the liquid crystal display elements according to the embodiment shown in FIG. 3A, and curve b shows the relationship between the liquid crystal display elements according to the comparative example shown in FIG.

  In the comparative example (curve b), as the twist angle increases, the retardation Δnd that provides the maximum transmittance also increases. On the other hand, in the example (curve a), the retardation Δnd at which the maximum reflectance is obtained does not significantly depend on the twist angle. Moreover, the value of retardation Δnd is small, and when compared with the comparative example, in the range of the twist angle of 70 ° to 110 °, the value obtained in the example is approximately 0.38 of the value obtained in the comparative example. For example, when the twist angle is 90 °, it is about 0.5 times.

  Therefore, the liquid crystal display element according to the embodiment adopting the reflection type configuration is compared with the liquid crystal display element according to the comparative example adopting the transmission type configuration, for example, when the birefringence Δn of the liquid crystal material is equal, The liquid crystal layer 55 thickness d of the cell 77 can be 0.38 times to 0.55 times.

  The falling response speed of the liquid crystal molecules is inversely proportional to the square of the liquid crystal layer thickness. In order to increase the response speed of the liquid crystal element, it is effective to increase the falling response speed of the liquid crystal molecules. Therefore, it can be said that the liquid crystal display element according to the embodiment is a liquid crystal display element capable of driving the area dividing liquid crystal cell 77 at high speed.

  FIG. 4B is a graph showing the twist angle dependence of contrast. The simulation for creating this graph was carried out using retardation Δnd that gives maximum reflectance / maximum transmittance at each twist angle, instead of making retardation Δnd constant. That is, FIG. 4B shows the calculated contrast for a liquid crystal cell having a retardation Δnd that gives the maximum reflectance / maximum transmittance at each twist angle.

  The horizontal axis of the graph indicates the twist angle in the unit “° (degrees)”. The vertical axis indicates the contrast in the unit “au (arbitrary unit)”. Curve c shows the relationship between the liquid crystal display elements according to the embodiment shown in FIG. 3A, and curve d shows the relationship between the liquid crystal display elements according to the comparative example shown in FIG. 3B.

  In the example (curve c) and the comparative example (curve d), there is a maximum contrast value (peak contrast) at a twist angle of 90 ° to 100 °. It can be seen that the example (curve c) has a smaller peak contrast value than the comparative example (curve d), and the black display performance is not good. This is because the influence of the wavelength dispersion characteristic of the circularly polarizing plate appears. Two wave plates (1/2 wave plate 69a and ¼ wave plate 69b) of the liquid crystal display device according to the embodiment shown in FIG. 3A are formed of a material having a small wavelength dispersion characteristic (for example, norbornene resin). Thus, the contrast can be improved.

  FIG. 4C is a graph showing the twist angle dependence of the maximum reflectance / maximum transmittance. The horizontal axis of the graph indicates the twist angle in the unit “° (degrees)”. The vertical axis represents the maximum reflectance / maximum transmittance in the unit “%”. Curve e represents the relationship between the liquid crystal display elements according to the embodiment shown in FIG. 3A, and curve f represents the relationship between the liquid crystal display elements according to the comparative example shown in FIG.

  In the comparative example (curve f), the maximum transmittance is almost constant regardless of the twist angle. On the other hand, in the example (curve e), the maximum reflectance largely changes with a peak of about 70 °.

  For example, in the FS drive for performing color display, the maximum reflectance / maximum transmittance is an important factor that determines the display quality, so it is desirable that it be as high as possible. On the other hand, black for black display is important for improving the color purity of color display. In consideration of the results shown in FIGS. 4A to 4C, when it is determined that both are preferable, the area dividing liquid crystal cell 77 of the liquid crystal display device according to the embodiment shown in FIG. The twist angle is 60 ° to 90 °, and the retardation Δnd is 0.18 μm to 0.26 μm.

  The inventor of the present application produced four types of modifications of the embodiment, and performed FS driving for each of them to confirm the display state.

  With reference to FIGS. 5A to 5C, configurations and operations common to the liquid crystal display elements according to the four types of modifications will be described.

  FIG. 5A is a plan view showing a display portion of the liquid crystal display element. The upper transparent electrode 52a and the lower transparent electrode 52b of the display liquid crystal cell 76 can define a display unit (a plurality of display units for displaying and a background region) on the upper substrate 50a side. The display unit includes dots 88a to 88u which are display units, a segment 89, and a background region 90. Each of the dots 88 a to 88 u and the segment 89 is provided with an electrode that can be driven independently of the display liquid crystal cell 76. By selectively applying a voltage to these electrodes, the alignment state of the liquid crystal molecules of the liquid crystal layer 55 corresponding to the electrodes can be changed, and various displays can be performed.

  The display unit is defined corresponding to the position where the upper transparent electrode 52a and the lower transparent electrode 52b of the display liquid crystal cell 76 face each other, and the background region is the upper transparent electrode 52a and the lower transparent electrode of the display liquid crystal cell 76. It is defined corresponding to the position where the electrode 52b does not face.

  FIG. 5B is a plan view showing an area defined on the upper substrate 50 a side of the area dividing liquid crystal cell 77.

  The area dividing liquid crystal cell 77 can divide and emit incident light for each predetermined area (two areas 86 and 87 in FIG. 5B) defined by the shape of the electrode. It is. The shapes of the areas 86 and 87 correspond to the electrode shape of the area dividing liquid crystal cell 77, and are defined at positions where the upper transparent electrode 52a and the lower transparent electrode 52b of the area dividing liquid crystal cell 77 face each other.

  The light emitted from the area 86 is incident on the area including the dots 88a to 88u, and the light emitted from the area 87 is incident on the area including the segment 89, and the liquid crystal cell for area division 77 and the liquid crystal cell for display 76 are displayed. Are arranged in alignment.

  FIG. 5C shows a display realized by operating four types of modifications by FS driving. The dots 88a to 88e, 88j, 88p, and 88u (shown with a slanting line slanting left in the figure) display the letter “L” in red and the segment 89 (in this figure). , Indicated by a slanting line with a downward slope to the right.), The letters “ST” were displayed in yellow. In this case, the dots 88a to 88e, 88j, 88p, 88u and the segment 89 are display areas, and dots and background areas which are not the remaining display areas are non-display areas (black).

  In the FS driving of the four types of modification examples, one frame is set to 16.7 ms and divided into two SFs (SF1 and SF2) each having 8.35 ms. The first 3 ms of both SFs was the blank period (the multi-color light 66 extinguishing period), and the remaining 5.35 ms was the light emission period. In the liquid crystal cell 76 for display, voltage was always applied only to a predetermined electrode described later. A voltage was applied to the area dividing liquid crystal cell 77 at a timing described later.

  With reference to FIGS. 6A to 6C, a liquid crystal display element according to a first modification and a driving method thereof will be described.

  FIG. 6A is a schematic exploded perspective view showing an example of the internal configuration of the liquid crystal display element according to the first modification. The first modification is a liquid crystal display element having a normally-off display liquid crystal cell 76 portion and a normally-on area dividing liquid crystal cell 77 portion.

  The first modification is similar to the embodiment shown in FIG. 3A, but uses a negative type liquid crystal material in which the display liquid crystal cell 76 is substantially vertically aligned on the surfaces of the upper and lower substrates 50a and 50b. The difference is that the vertical alignment cell used is used. Another difference is that two polarizing plates (an upper polarizing plate 54a and a central polarizing plate 54i) on the upper and lower substrates 50a and 50b of the display liquid crystal cell 76 are arranged in crossed Nicols. In the first modification, the twist angle of the liquid crystal molecules and the retardation Δnd of the liquid crystal layer 55 of the TN type liquid crystal cell 77 are 70 ° and 0.245 μm, respectively.

  FIG. 6B is a table showing the application / non-application of voltage to the electrodes of the display liquid crystal cell 76. The dots 88a to 88u and the electrodes corresponding to the segments 89 shown in FIG. “ON” in the drawing indicates that a voltage is applied through SF1 to SF3, and “OFF” indicates that no voltage is applied through SF1 to SF3.

  Among the electrodes corresponding to the 20 dots of the dots 88a to 88u, the voltage is applied to the electrodes corresponding to the 8 dots of the dots 88a to 88e, 88j, 88p, and 88u, and the electrode to which the voltage is applied. When dots corresponding to are connected, an “L” shape is formed. A voltage is also applied to the electrode corresponding to the segment 89 displaying “ST”.

  The liquid crystal element portion composed of the upper polarizing plate 54a, the display liquid crystal cell 76, and the central polarizing plate 54i is normally off. Therefore, the liquid crystal element portion transmits only light incident on “L” by dots and “ST” by segments.

  FIG. 6C is a table summarizing application / non-application of voltage to the area dividing liquid crystal cell 77 and turning on / off of the multi-color light 66.

  The application / non-application of voltage to the area dividing liquid crystal cell 77 is shown for each electrode corresponding to the areas 86 and 87 shown in FIG. In the column of “area division liquid crystal cell 77”, “ON” indicates that a voltage is applied to the corresponding electrode with the corresponding SF, and “OFF” indicates that no voltage is applied to the corresponding electrode with the corresponding SF. It shows that.

  In addition, in the column of “multi-color light 66 lighting color”, the color that is turned on in the corresponding SF is described.

  The liquid crystal element portion composed of the central polarizing plate 54i, the quarter wavelength plate 69 (the half wavelength plate 69a and the quarter wavelength plate 69b), the area dividing liquid crystal cell 77, and the reflection plate 67 is normally on. (Light that is incident on the central polarizing plate 54i in a state where no voltage is applied to the area dividing liquid crystal cell 77 is reflected by the reflecting plate 67 and then passes through the central polarizing plate 54i again). For this reason, in the liquid crystal element portion, only the light incident on the area where no voltage is applied to the corresponding electrode is reflected by the reflecting plate 67 and then passes through the central polarizing plate 54i again.

  Refer to the SF1 row. In SF1, red light is emitted from the multi-color light 66. The area dividing liquid crystal cell 77 does not apply a voltage to the area 86 but applies a voltage to the area 87.

  For this reason, red light emitted from the multi-color light 66 and incident on the area 87 is reflected by the reflecting plate 67 and then blocked by the central polarizing plate 54i. On the other hand, the red light incident on the portion other than the area 87 (including the area 86) passes through the central polarizing plate 54i and the multi-color light 66 and enters the lower substrate 50b of the display liquid crystal cell 76. Among these, only red light incident on “L” by the dots is transmitted through the upper polarizing plate 54 a of the display liquid crystal cell 76 and visually recognized by the observer.

  Refer to the SF2 line. In SF2, yellow light is emitted from the multi-color light 66. The area dividing liquid crystal cell 77 applies a voltage to the area 86 and does not apply a voltage to the area 87.

  For this reason, the yellow light emitted from the multi-color light 66 and incident on the area 86 is reflected by the reflecting plate 67 and then blocked by the central polarizing plate 54i. On the other hand, the yellow light that has entered the portion other than the area 86 (including the area 87) passes through the central polarizing plate 54i and the multi-color light 66 and enters the lower substrate 50b of the display liquid crystal cell 76. Of these, only yellow light incident on “ST” by the segment passes through the upper polarizing plate 54a of the display liquid crystal cell 76 and is visually recognized by the observer.

  In this way, as shown in FIG. 5C, red “L” characters can be displayed in dots on a black background, and yellow “ST” characters can be displayed in segments. .

  When the inventor of the present application has driven the liquid crystal display element according to the first modification as described above, the red “L” is actually displayed in dots, the yellow “ST” is displayed in segments, and the black background is displayed. Could be realized inside. As a result of research by the inventors of the present application, when the display liquid crystal cell 76 is set to a normally-off mode, it has been found that when a vertical alignment type liquid crystal cell is adopted as the display liquid crystal cell 76, the appearance is good. This is presumably because the vertically aligned liquid crystal cell is excellent in viewing angle characteristics.

  With reference to FIGS. 7A to 7C, a liquid crystal display element according to a second modification and a driving method thereof will be described.

  FIG. 7A is a schematic exploded perspective view showing an example of the internal configuration of the liquid crystal display element according to the second modification. The second modification is a liquid crystal display element having both a normally-off display liquid crystal cell 76 portion and an area dividing liquid crystal cell 77 portion.

  The second modification differs from the first modification in that the dividing liquid crystal cell 77 is a vertical alignment cell using a negative liquid crystal material that is substantially vertically aligned on the surfaces of the upper and lower substrates 50a and 50b. . In the second modification, the retardation Δnd of the liquid crystal layer 55 of the vertical alignment type dividing liquid crystal cell 77 is set to 0.2 μm.

  FIG. 7B is a table showing application / non-application of voltage to the electrodes of the liquid crystal cell 76 for display.

  As in the case of the first modification, among the electrodes corresponding to the 20 dots of the dots 88a to 88u, the voltage is applied to the 8 dots of the dots 88a to 88e, 88j, 88p, and 88u. When the dots corresponding to the electrodes to which the voltage is applied are connected, the “L” shape is obtained. A voltage is also applied to the electrode corresponding to the segment 89 displaying “ST”.

  Similarly to the first modification, the liquid crystal element portion including the upper polarizing plate 54a, the display liquid crystal cell 76, and the central polarizing plate 54i is normally off. , And only the light incident on “ST” by the segment is transmitted.

  FIG. 7C is a table summarizing application / non-application of voltage to the area dividing liquid crystal cell 77 and turning on / off of the multi-color light 66.

  The liquid crystal element portion constituted by the central polarizing plate 54i, the quarter wavelength plate 69 (the half wavelength plate 69a and the quarter wavelength plate 69b), the area dividing liquid crystal cell 77, and the reflection plate 67 is normally off ( The light incident on the central polarizing plate 54i in a state where no voltage is applied to the area dividing liquid crystal cell 77 is reflected by the reflecting plate 67 and then blocked by the central polarizing plate 54i. For this reason, in the liquid crystal element portion, only the light incident on the area where the voltage is applied to the corresponding electrode is reflected by the reflecting plate 67 and then passes through the central polarizing plate 54i again.

  Refer to the SF1 row. In SF1, red light is emitted from the multi-color light 66. The area dividing liquid crystal cell 77 applies a voltage to the area 86 and does not apply a voltage to the area 87.

  For this reason, red light emitted from the multi-color light 66 and incident on portions other than the area 86 (including the area 87) is reflected by the reflecting plate 67 and then blocked by the central polarizing plate 54i. On the other hand, the red light incident on the area 86 passes through the central polarizing plate 54 i and the multi-color light 66 and enters the lower substrate 50 b of the display liquid crystal cell 76. Among these, only red light incident on “L” by the dots is transmitted through the upper polarizing plate 54 a of the display liquid crystal cell 76 and visually recognized by the observer.

  Refer to the SF2 line. In SF2, yellow light is emitted from the multi-color light 66. The area dividing liquid crystal cell 77 does not apply a voltage to the area 86 but applies a voltage to the area 87.

  For this reason, yellow light emitted from the multi-color light 66 and incident on portions other than the area 87 (including the area 86) is reflected by the reflecting plate 67 and then blocked by the central polarizing plate 54i. On the other hand, the yellow light incident on the area 87 passes through the central polarizing plate 54 i and the multi-color light 66 and enters the lower substrate 50 b of the display liquid crystal cell 76. Of these, only yellow light incident on “ST” by the segment passes through the upper polarizing plate 54a of the display liquid crystal cell 76 and is visually recognized by the observer.

  In this way, as shown in FIG. 5C, red “L” characters can be displayed in dots on a black background, and yellow “ST” characters can be displayed in segments. .

  When the present inventor has driven the liquid crystal display element according to the second modification as described above, the red “L” is actually displayed in dots, the yellow “ST” is displayed in segments, and the black background is displayed. Could be realized inside.

  With reference to FIGS. 8A to 8C, a liquid crystal display element according to a third modification and a driving method thereof will be described.

  FIG. 8A is a schematic exploded perspective view showing an example of the internal configuration of the liquid crystal display element according to the third modification. A third modification is a liquid crystal display element having both a normally-on display liquid crystal cell 76 portion and an area dividing liquid crystal cell 77 portion.

  The third modification is similar to the embodiment shown in FIG. 3A, but two polarizing plates (upper polarizing plate 54a) on the upper side of the display liquid crystal cell 76 and on the outer side of the lower substrates 50a and 50b. And the central polarizing plate 54i) is different in that it is arranged in crossed Nicols. Another difference is that a black mask 59 covering the background region is disposed on the liquid crystal layer 55 side of the upper substrate 50a of the display liquid crystal cell 76. In the third modification, the liquid crystal layer 55 of the TN type liquid crystal cell 77 for division has a twist angle of liquid crystal molecules of 70 ° and a retardation Δnd of 0.245 μm.

  FIG. 8B is a table showing the application / non-application of voltage to the electrodes of the display liquid crystal cell 76.

  Of the electrodes corresponding to the 20 dots of the dots 88a to 88u, the electrode to which no voltage is applied is the electrode corresponding to the 8 dots of the dots 88a to 88e, 88j, 88p, and 88u, and the electrode to which no voltage is applied. When dots corresponding to are connected, an “L” shape is formed. Also, no voltage is applied to the electrode corresponding to the segment 89 displaying “ST”.

  The liquid crystal element portion composed of the upper polarizing plate 54a, the display liquid crystal cell 76, and the central polarizing plate 54i is normally on. Therefore, the liquid crystal element portion transmits only light incident on “L” by dots and “ST” by segments.

  FIG. 8C is a table summarizing the application / non-application of voltage to the area dividing liquid crystal cell 77 and the turning on / off of the multi-color light 66.

  The liquid crystal element portion composed of the central polarizing plate 54i, the quarter wavelength plate 69 (the half wavelength plate 69a and the quarter wavelength plate 69b), the area dividing liquid crystal cell 77, and the reflection plate 67 is normally on. (Light that is incident on the central polarizing plate 54i in a state where no voltage is applied to the area dividing liquid crystal cell 77 is reflected by the reflecting plate 67 and then passes through the central polarizing plate 54i again). For this reason, in the liquid crystal element portion, light incident on a portion other than the area where the voltage is applied to the corresponding electrode is reflected by the reflecting plate 67 and then passes through the central polarizing plate 54i again.

  Refer to the SF1 row. In SF1, red light is emitted from the multi-color light 66. The area dividing liquid crystal cell 77 does not apply a voltage to the area 86 but applies a voltage to the area 87.

  For this reason, red light emitted from the multi-color light 66 and incident on the area 87 is reflected by the reflecting plate 67 and then blocked by the central polarizing plate 54i. On the other hand, the red light incident on the portion other than the area 87 (including the area 86) passes through the central polarizing plate 54i and the multi-color light 66 and enters the lower substrate 50b of the display liquid crystal cell 76. Among these, only red light incident on “L” by the dots is transmitted through the upper polarizing plate 54 a of the display liquid crystal cell 76 and visually recognized by the observer.

  Refer to the SF2 line. In SF2, yellow light is emitted from the multi-color light 66. The area dividing liquid crystal cell 77 applies a voltage to the area 86 and does not apply a voltage to the area 87.

  For this reason, the yellow light emitted from the multi-color light 66 and incident on the area 86 is reflected by the reflecting plate 67 and then blocked by the central polarizing plate 54i. On the other hand, the yellow light that has entered the portion other than the area 86 (including the area 87) passes through the central polarizing plate 54i and the multi-color light 66 and enters the lower substrate 50b of the display liquid crystal cell 76. Of these, only yellow light incident on “ST” by the segment passes through the upper polarizing plate 54a of the display liquid crystal cell 76 and is visually recognized by the observer.

  In this way, as shown in FIG. 5C, red “L” characters can be displayed in dots on a black background, and yellow “ST” characters can be displayed in segments. .

  When the present inventor has driven the liquid crystal display element according to the third modification as described above, the red “L” is actually displayed in dots, the yellow “ST” is displayed in segments, and the black background is displayed. Could be realized inside.

  With reference to FIGS. 9A to 9C, a liquid crystal display element according to a fourth modification and a driving method thereof will be described.

  FIG. 9A is a schematic exploded perspective view showing an example of the internal configuration of the liquid crystal display element according to the fourth modification. The fourth modification is a liquid crystal display element having a normally-on display liquid crystal cell 76 portion and a normally-off area dividing liquid crystal cell 77 portion.

  The fourth modification is the same as the third modification with respect to the liquid crystal element portion composed of the upper polarizing plate 54a, the display liquid crystal cell 76 (including the black mask 59), and the central polarizing plate 54i. . Further, a liquid crystal element portion constituted by the central polarizing plate 54i, the quarter wavelength plate 69 (the half wavelength plate 69a and the quarter wavelength plate 69b), the area dividing liquid crystal cell 77, and the reflection plate 67 is described. This is the same as the second modification.

  FIG. 9B is a table showing the application / non-application of voltage to the electrodes of the display liquid crystal cell 76.

  Of the electrodes corresponding to the 20 dots of the dots 88a to 88u, the electrode to which no voltage is applied is the electrode corresponding to the 8 dots of the dots 88a to 88e, 88j, 88p, and 88u, and the electrode to which no voltage is applied. When dots corresponding to are connected, an “L” shape is formed. Also, no voltage is applied to the electrode corresponding to the segment 89 displaying “ST”.

  The liquid crystal element portion composed of the upper polarizing plate 54a, the display liquid crystal cell 76, and the central polarizing plate 54i is normally on. Therefore, the liquid crystal element portion transmits only light incident on “L” by dots and “ST” by segments.

  FIG. 9C is a table summarizing application / non-application of voltage to the area dividing liquid crystal cell 77 and turning on / off of the multi-color light 66.

  The liquid crystal element portion constituted by the central polarizing plate 54i, the quarter wavelength plate 69 (the half wavelength plate 69a and the quarter wavelength plate 69b), the area dividing liquid crystal cell 77, and the reflection plate 67 is normally off ( The light incident on the central polarizing plate 54i in a state where no voltage is applied to the area dividing liquid crystal cell 77 is reflected by the reflecting plate 67 and then blocked by the central polarizing plate 54i. For this reason, in the liquid crystal element portion, only the light incident on the area where the voltage is applied to the corresponding electrode is reflected by the reflecting plate 67 and then passes through the central polarizing plate 54i again.

  Refer to the SF1 row. In SF1, red light is emitted from the multi-color light 66. The area dividing liquid crystal cell 77 applies a voltage to the area 86 and does not apply a voltage to the area 87.

  For this reason, red light emitted from the multi-color light 66 and incident on portions other than the area 86 (including the area 87) is reflected by the reflecting plate 67 and then blocked by the central polarizing plate 54i. On the other hand, the red light incident on the area 86 passes through the central polarizing plate 54 i and the multi-color light 66 and enters the lower substrate 50 b of the display liquid crystal cell 76. Among these, only red light incident on “L” by the dots is transmitted through the upper polarizing plate 54 a of the display liquid crystal cell 76 and visually recognized by the observer.

  Refer to the SF2 line. In SF2, yellow light is emitted from the multi-color light 66. The area dividing liquid crystal cell 77 does not apply a voltage to the area 86 but applies a voltage to the area 87.

  For this reason, yellow light emitted from the multi-color light 66 and incident on portions other than the area 87 (including the area 86) is reflected by the reflecting plate 67 and then blocked by the central polarizing plate 54i. On the other hand, the yellow light incident on the area 87 passes through the central polarizing plate 54 i and the multi-color light 66 and enters the lower substrate 50 b of the display liquid crystal cell 76. Of these, only yellow light incident on “ST” by the segment passes through the upper polarizing plate 54a of the display liquid crystal cell 76 and is visually recognized by the observer.

  In this way, as shown in FIG. 5C, red “L” characters can be displayed in dots on a black background, and yellow “ST” characters can be displayed in segments. .

  When the present inventor has driven the liquid crystal display element according to the fourth modification as described above, the red “L” is actually displayed in dots, the yellow “ST” is displayed in segments, and the black background is displayed. Could be realized inside.

  According to the driving method described above, various color displays are possible in that light of an arbitrary color can be emitted from the multi-color light. Further, as shown in the embodiment, display in different colors is possible for each area. For example, if three areas and three SFs are provided, and light of different colors is emitted from the multi-color light in each SF, display can be performed in different colors for each area. When one frame is divided into n SFs, it is possible to display n + 1 colors including the non-display area color (black).

  In addition, since the display units belonging to one area are displayed with light from the light only in at most one SF, a color break can be prevented.

  Furthermore, as described above, the liquid crystal display elements according to the embodiments and the modification examples are liquid crystal display elements in which the area dividing liquid crystal cell can be made thin, and therefore, high speed operation is possible. For this reason, it is easy to increase the number of SFs in one frame, and various color displays are possible in this respect as well.

  A feature of the liquid crystal display element according to the embodiment and the modification is that a multi-color light is arranged between the display liquid crystal cell and the area dividing liquid crystal cell.

  For example, in the configuration in which the light is arranged on the light extraction surface side, leakage light from the light may be observed. However, according to the liquid crystal display elements according to the present embodiment and the modification, this point is improved and the display quality is improved. Can be improved.

  Further, for example, in the configuration in which the light is arranged on the light extraction surface side, the display position is deepened by the thickness of the light. However, according to the liquid crystal display element according to the present embodiment and the modification, the display position is Therefore, the display quality can be improved.

  As mentioned above, although this invention was demonstrated along the Example, this invention is not limited to these. It will be apparent to those skilled in the art that various modifications, improvements, combinations, and the like can be made.

  It can be used as a segment type, a full dot type, a composite type liquid crystal display element of segment display and dot display, and a driving method thereof. The driving method may be simple matrix driving or active matrix driving.

(A)-(E) are the figures for demonstrating simply regarding the liquid crystal display device based on Japanese Patent Application No. 2004-118870. It is a schematic exploded perspective view which shows the example of an internal structure of the liquid crystal display element by an Example. (A) is a schematic exploded perspective view showing an internal configuration example of a liquid crystal display element according to an embodiment used in the simulation, and (B) is a schematic view showing an internal configuration example of a liquid crystal display element according to a comparative example. It is a disassembled perspective view. (A)-(C) is a graph which shows the result analyzed about the liquid crystal cell 77 for area division of an Example and a comparative example. (A)-(C) are the figures for demonstrating the structure and operation | movement common to the liquid crystal display element by four types of modifications. (A)-(C) are the figures for demonstrating the liquid crystal display element by the 1st modification, and its drive method. (A)-(C) are the figures for demonstrating the liquid crystal display element by the 2nd modification, and its drive method. (A)-(C) are the figures for demonstrating the liquid crystal display element by the 3rd modification, and its drive method. (A)-(C) are the figures for demonstrating the liquid crystal display element by the 4th modification, and its drive method. It is a schematic exploded perspective view which shows the internal structural example of the liquid crystal display element which performs a color display. (A) is a schematic exploded perspective view showing an example of the internal configuration of a liquid crystal display element capable of performing FS driving, and (B) is a plan view showing a display unit of the liquid crystal display element. It is a timing chart which shows an example of the display control in the liquid crystal display element using a FS drive system. It is a timing chart for demonstrating the drive method of the liquid crystal display element by a previous proposal.

Explanation of symbols

30 Display unit 31 to 37 Display unit 38 Background region 50a Upper substrate 50b Lower substrate 51a Upper glass substrate 51b Lower glass substrate 52a Upper transparent electrode 52b Lower transparent electrode 53a Upper alignment film 53b Lower alignment film 54a Upper polarizer 54b Lower polarizing plate 54i Central polarizing plate 55 Liquid crystal layer 56 Multi-color backlight 57 White backlight 59 Black mask 60 Area color filter 60r Red portion 60g Green portion 60b Blue portion 60w White portion 66 Multi-color light 67 Reflector 68 Voltage applying means 69 1/4 wavelength plate 69a 1/2 wavelength plate 69b 1/4 wavelength plate 70 Multi-color front light 75 Backlight synchronous drive circuit 76 Display liquid crystal cell 77 Area division liquid crystal cell 78 Synchronous circuits 81-83, 86, 87 Area 88a-88u dot 89 segment 90 background area

Claims (12)

A plate-like light source that emits light;
A first polarizing plate on which light emitted from the light source is incident;
A first liquid crystal cell into which light transmitted through the first polarizing plate is incident; (i) a first substrate including a first electrode having a predetermined shape; and (ii) the first substrate; A second substrate provided with a second electrode of a predetermined shape, disposed substantially parallel to the opposite side of the first polarizing plate, wherein the first electrode and the second electrode are A second substrate having a first area and a second area defined at opposite positions; and (iii) disposed between the first substrate and the second substrate; A first liquid crystal layer capable of switching an alignment state by applying a voltage between the second electrode and the second electrode; (iV) the first liquid crystal layer side of the second substrate; Or disposed on the opposite side of the first liquid crystal layer, reflects the light transmitted through the first liquid crystal layer and emits it from the first liquid crystal cell; A reflecting plate that is incident on one polarizing plate and transmits at least a part thereof, and the light that has passed through the first polarizing plate reciprocates through the first liquid crystal cell and then returns to the first polarizing plate. When incident, according to the orientation state, light emitted from one of the first area and the second area is transmitted through the first polarizing plate, and the light emitted from the other is the first polarized light. A first liquid crystal cell that can be prevented from passing through the plate;
A second liquid crystal cell on which light reflected by the reflecting plate and transmitted through the first polarizing plate is incident, (i) a third substrate including a third electrode having a predetermined shape; and (ii) ) A fourth substrate provided with a fourth electrode having a predetermined shape and disposed substantially parallel to the third substrate, wherein the third electrode and the fourth electrode are opposed to each other. A fourth substrate in which a first display unit on which light transmitted through the first area is incident and a second display unit on which light transmitted through the second area is incident are defined; (iii) A second substrate disposed between the third substrate and the fourth substrate and capable of switching an alignment state by applying a voltage between the third electrode and the fourth electrode; A second liquid crystal cell comprising a liquid crystal layer;
A second polarizing plate disposed on the opposite side of the second liquid crystal cell from the first polarizing plate, on which light transmitted through the second liquid crystal cell is incident;
When a period for displaying one image is one frame, one frame is time-divided into a plurality of subframes, the light sources are emitted in each subframe, and the first light source is synchronized with the light emission of the light sources. A liquid crystal display element having a control circuit capable of switching an alignment state of a liquid crystal cell.   The control circuit controls light emission of the light source so that display is performed with light emitted from the light source in at least one sub-frame in each of the first and second display units. Item 2. A liquid crystal display device according to item 1.   The liquid crystal display element according to claim 1, wherein the control circuit controls the light source to emit light of different colors in all subframes in one frame.   Furthermore, the said 1st liquid crystal cell contains the quarter wavelength plate which forms a circularly-polarizing plate in combination with a said 1st polarizing plate in the said 1st polarizing plate side of the said 1st board | substrate. The liquid crystal display element of any one of -3.   The liquid crystal display element according to claim 4, further comprising a half-wave plate used in combination with the quarter-wave plate.   The liquid crystal display element according to claim 1, wherein the first liquid crystal cell is a twisted nematic liquid crystal cell and has a twist angle of 60 ° to 90 °.   The liquid crystal display element according to claim 6, wherein the retardation of the first liquid crystal layer is 0.18 μm to 0.26 μm.   The liquid crystal display element according to any one of claims 1 to 7, wherein a portion configured by the first polarizing plate, the second liquid crystal cell, and the second polarizing plate is in a normally-off mode.   The liquid crystal display element according to claim 8, wherein the second liquid crystal cell is a vertical alignment type liquid crystal cell.   The liquid crystal display element according to claim 1, wherein the second liquid crystal cell includes a black mask.   The liquid crystal display element according to claim 1, wherein the light source can selectively emit a plurality of colors of light. A plate-like light source that emits light, a first polarizing plate on which light emitted from the light source is incident, and a first liquid crystal cell on which light transmitted through the first polarizing plate is incident, (i ) A first substrate having a first electrode of a predetermined shape; and (ii) a second of a predetermined shape disposed substantially parallel to the first substrate and opposite to the first polarizing plate. A second substrate having a first area and a second area defined at a position where the first electrode and the second electrode face each other. And (iii) switching the alignment state by applying a voltage between the first electrode and the second electrode, which is disposed between the first substrate and the second substrate. A first liquid crystal layer capable of forming (iV) the first liquid crystal layer side of the second substrate, or the opposite side of the first liquid crystal layer; A reflection plate that reflects the light transmitted through the first liquid crystal layer, emits the light from the first liquid crystal cell, enters the first polarizing plate, and transmits at least a part thereof; When the light transmitted through the polarizing plate travels back and forth through the first liquid crystal cell and is incident on the first polarizing plate again, one of the first area and the second area according to the alignment state. The first liquid crystal cell that can prevent the light emitted from the first polarizing plate from passing through the first polarizing plate and the light emitted from the other from passing through the first polarizing plate is reflected by the reflector. A second liquid crystal cell on which light transmitted through the first polarizing plate is incident, wherein (i) a third substrate including a third electrode having a predetermined shape; and (ii) the third substrate; A fourth substrate provided with a fourth electrode having a predetermined shape and arranged substantially in parallel, wherein the third electrode A first display unit in which light transmitted through the first area is incident on a position facing the fourth electrode, and a second display unit in which light transmitted through the second area is incident A defined fourth substrate; and (iii) applying a voltage between the third electrode and the fourth electrode, disposed between the third substrate and the fourth substrate. And a second liquid crystal cell comprising a second liquid crystal layer capable of switching an alignment state, and disposed on the opposite side of the second liquid crystal cell from the first polarizing plate, When the second polarizing plate on which light transmitted through the liquid crystal cell is incident and the period for displaying one image is one frame, one frame is time-divided into a plurality of sub-frames, The alignment state of the first liquid crystal cell is switched in synchronization with the light emission of the light source. A method of driving a liquid crystal display element having a control circuit that can be switched,
In a subframe, displaying with the light emitted from the first area;
In another sub-frame, display is performed with light emitted from the second area, and each of the first and second display units is displayed in at most one sub-frame in one frame. A driving method of a liquid crystal display element.

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