JP2007199158A - Liquid crystal display element and method for driving liquid crystal display element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal display element with which a wide variety of colors are displayed. <P>SOLUTION: The liquid crystal display element has: a first substrate equipped with a first electrode; a second substrate equipped with a second electrode and delimiting display units including first and second display units and a background region; a liquid crystal layer disposed between the first and second substrates; a first polarizing plate placed opposite to the first substrate; a first light source placed opposite to the first polarizing plate; a transmission/reflection plate placed opposite to the second substrate and transmitting or reflecting incident light depending on the polarization state; a second polarizing plate placed opposite to the transmission/reflection plate; a second light source placed opposite to the second polarizing plate and equipped with first and second emission ports for respectively conducting display in the first and second display units; a voltage applying means to apply voltage between the first and second electrodes; and a control circuit with which a frame is time divided into sub-frames, and the first or the second light source is made to emit light within respective sub-frames. In the liquid crystal display element, the transmission/reflection plate reflects light in the polarization state of being transmitted through the first polarizing plate and the liquid crystal layer with no voltage applied thereto, and transmits light in the polarization state of being transmitted through the second polarizing plate. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

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

  In the segment type, dot matrix type, and liquid crystal display elements that combine both, the display color of the area other than the segment or dot used for display (non-display area) can be adjusted to improve display visibility and design. Improvements are being made.

  FIGS. 9A to 9C are schematic exploded perspective views showing an example of the internal configuration of a liquid crystal display element capable of adjusting the color tone of the non-display area.

  Reference is made to FIG. 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 liquid crystal layer formed of, for example, nematic liquid crystal having a positive dielectric anisotropy (Δε> 0), and the twist angle determined by the rubbing directions of the upper and lower alignment films 53a and 53b is For example, 90 degrees.

  On the outside of the upper substrate 50a and the lower substrate 50b, a pair of upper and lower polarizing plates 54a and 54b are arranged in a crossed Nicols state along the rubbing direction. 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. With no voltage applied, the polarization direction of the incident light rotates according to the orientation of the liquid crystal molecules and transmits through the polarizing plate to perform normally white display. In FIG. 9A, the direction of the transmission axis is indicated by an arrow.

  A multi-color backlight 56 is disposed outside the lower polarizing plate 54b. The multi-color backlight 56 is a backlight that can emit light of a plurality of colors, and uses, for example, an RGB multi-color LED light source.

  The voltage application means connected between the upper and lower transparent electrodes 52a and 52b applies a voltage to the liquid crystal layer 55, so that the liquid crystal molecules rise from the horizontal direction to the vertical direction. It is not affected by the layer and is shielded by the cross polarizer.

  When the light emitted from the multi-color backlight 56 and passed through the liquid crystal layer 55 is transmitted through the upper polarizing plate 54a, “bright” is displayed by the color of the emitted light, and when the light is blocked by the upper polarizing plate 54a, “ A “dark” display is made.

  In a normally white type liquid crystal display element that displays the display area in black using “dark” display, the color tone of the non-display area can be obtained by using a multi-color backlight that can change the emission color of the backlight. Can be arbitrarily changed.

  Reference is made to FIG. The liquid crystal display element shown in FIG. 9B uses upper and lower color polarizing plates 54c and 54d instead of the upper and lower polarizing plates 54a and 54b, as compared with that shown in FIG. 9A. And in that a white backlight 57 is used instead of the multi-color backlight 56.

  The white backlight 57 is configured by using, for example, a cold cathode fluorescent lamp (CCFL). In some cases, an inorganic white LED (light emitting diode), an organic white LED, or the like is used.

  The upper and lower color polarizing plates 54c and 54d are arranged in a crossed Nicols arrangement.

  The upper and lower polarizing plates 54a and 54b in FIG. 9A are, for example, neutral gray color polarizing plates, while the upper and lower polarizing plates 54c and 54d in FIG. Color polarizing plate. By transmitting the light emitted from the white backlight 57 through the upper and lower color polarizing plates 54c and 54d, the background color can be set to the color determined by the upper and lower color polarizing plates 54c and 54d. .

  Reference is made to FIG. The liquid crystal display element shown in FIG. 9C is different from that shown in FIG. 9B in that a retardation plate 58 is inserted between the upper polarizing plate 54a and the upper substrate 50a. By inserting the phase difference plate 58, the color tone of the non-display area can be adjusted.

  The color tone of the non-display area can be adjusted by adjusting the thickness of the liquid crystal layer, the twist degree of the liquid crystal molecules, a combination of a polarizing plate and a retardation plate, and the like.

  Note that in the liquid crystal display element shown in FIGS. 9B and 9C, the color of the non-display area cannot be changed after the element is completed.

  FIGS. 10A and 10B are schematic exploded perspective views showing an example of the internal configuration of a liquid crystal display element capable of adjusting the color tone of a dot portion or a segment portion.

  Reference is made to FIG. The liquid crystal display element shown in FIG. 10A is different from that shown in FIG. 9A in that an area color filter 60 and a black mask 59 are arranged between the upper and lower substrates 50a and 50b. Another difference is that a white backlight 57 is used instead of the multi-color backlight 56.

  The area color filter 60 includes, for example, a red part 60r, a green part 60g, a blue part 60b, and a white part 60w. In the illustrated liquid crystal display element, light emitted from the white backlight 57 passes through different color regions (each color portion 60 r, g, b, w) of the area color filter 60, thereby displaying a plurality of colors. It becomes possible.

  The black mask 59 covers the boundary of the color area and is arranged to increase contrast and color purity.

  Reference is made to FIG. The liquid crystal display element shown in FIG. 10B differs from that shown in FIG. 9A in that the upper and lower polarizing plates 54a and 54b are arranged in parallel Nicols. When light emitted from the multi-color backlight 56 is polarized by the lower polarizing plate 54b and rotated in accordance with the alignment state of the liquid crystal molecules when no voltage is applied, the polarization direction of the upper polarizing plate 54a is orthogonal. , Shielded from light. That is, the liquid crystal display element shown in this figure is a normally black type liquid crystal display element using a multi-color backlight. A plurality of colors can be displayed depending on the color of light emitted when a voltage is applied.

  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. In the liquid crystal display element shown in FIG. 11A, a backlight synchronous driving circuit 75 is added to that shown in FIG.

  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 cell (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 56 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 (three) of sub-frames (SB). 1SB is, for example, 5.57 ms.

  Refer to the “Multi-color backlight” stage. One SB is divided into a light emission period and a blank period. During the light emission period of each SB (SB1 to SB3), 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 SB1, SB2, and SB3.

  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 change the alignment state to some extent 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 liquid crystal display element is in a state of transmitting light, and “OFF” indicates that the liquid crystal display element is in a state of not transmitting light. It shows that there is.

  In the display unit 31, light is transmitted through SB1 and SB2. 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”. In the display unit 32, light is transmitted through SB1 and SB3. Therefore, the observer recognizes magenta (M), which is a mixed color of R and B.

  Reference is made to the column “Display Unit 37”. In the display unit 37, light is transmitted in SB2. Therefore, 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 vibration is applied to the liquid crystal display element, images of the SBs 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 the color break phenomenon by forming light of a desired color for each SB and causing it to emit light, and setting the display unit in a light-transmitting state in one SB to a light-blocking state in another SB. A driving method of the liquid crystal display device was proposed. (For example, see Patent Document 1.)
FIG. 13 is a timing chart for explaining the liquid crystal driving method according to the previous proposal.

  Refer to the “Multi-color backlight” stage. In one frame shown, in SB1, white light is emitted by simultaneous lighting of a plurality of light sources, orange is emitted in SB2, and blue light is emitted by single light source emission in SB3. In this figure, the blank period is set to 3 ms in the 1SB period of 5.57 ms.

  Reference is made to the column “Display Unit 31”. In the display unit 31, only SB1 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 SBs are in a light shielding state. Therefore, the display color is black.

  Reference is made to the column “Display Unit 37”. In the display unit 37, only SB2 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, since the lighting color of the multi-color backlight can be changed for each frame, various color displays are possible.

  However, with the above-described technique, it is difficult to control the display area and the non-display area separately to each other and to an arbitrary color tone after manufacturing the liquid crystal display element. If it is a full dot matrix liquid crystal display element using a micro color filter, it is possible to make it possible to adjust the color of the non-display area and the display area independently, but the micro color filter The use of increases the cost.

In particular, in the case of a segment type or a segment and dot composite type liquid crystal display element, low cost is required, so it is preferable not to use a color filter such as a micro color filter. (For example, see Patent Document 2.)
In FS driving, the optical response of the liquid crystal layer is preferably completed within one SB. When FS driving is performed using a liquid crystal display element including a liquid crystal layer having a slow optical response, an intended display color may be difficult to obtain. In particular, when a simple matrix drive is performed in a dot matrix display element having a large duty ratio, for example, a liquid crystal operation mode (for example, STN mode) having a low response speed is usually used, so that an intended display state can be realized. It is often difficult.

JP-A-2005-070440 Japanese Patent Laid-Open No. 49-074438

  An object of the present invention is to provide a liquid crystal display element capable of displaying various colors and a driving method thereof.

  According to one aspect of the present invention, a first substrate provided with a first electrode having a predetermined shape, and a second substrate provided with a second electrode having a predetermined shape disposed substantially parallel to the first substrate. A plurality of display units including a first display unit and a second display unit that perform display at a position where the first electrode and the second electrode are opposed to each other, and the first electrode And a second substrate in which a background region is defined in a position where the second electrode and the second electrode do not face each other, and the first substrate and the second substrate are disposed between the first substrate and the second substrate. A liquid crystal layer capable of switching an alignment state by applying a voltage between the first electrode and the first electrode disposed on the opposite side of the first substrate from the side on which the liquid crystal layer is disposed. A polarizing plate, a first light source disposed on the opposite side of the first polarizing plate from the side on which the first substrate is disposed, and the second light source. A transmitting / reflecting plate that transmits or reflects incident light according to a polarization state, disposed on a side opposite to the side on which the liquid crystal layer is disposed, and the second substrate of the transmitting / reflecting plate. A second polarizing plate disposed on the opposite side of the disposed side, and a second polarizing plate disposed on the opposite side of the second polarizing plate from the side on which the transmission / reflecting plate is disposed. Applying a voltage between the first electrode and the second electrode, a second light source having first and second emission ports capable of performing display of the first and second display units; When the voltage application means and the period for displaying one image are one frame, one frame is time-divided into a plurality of subframes, and the first or second light source is caused to emit light within each subframe. A control circuit capable of transmitting the transmission / reflection plate A polarizing state of light transmitted through the liquid crystal layer when no voltage is applied, and a polarized state of light transmitted through the second polarizing plate, and the second polarizing plate and the transmitted light. The light transmitted through the reflector and the liquid crystal layer when no voltage is applied is shielded by the first polarizing plate, and is normally black type liquid crystal display with respect to the light emitted from the second light source An element is provided.

  According to another aspect of the present invention, a first substrate including a first electrode having a predetermined shape, and a second electrode having a predetermined shape disposed substantially parallel to the first substrate are provided. A plurality of display units including a first display unit and a second display unit for displaying at a position where the first electrode and the second electrode are opposed to each other; A second substrate having a background region defined at a position where the first electrode and the second electrode do not face each other; and the first electrode is disposed between the first substrate and the second substrate. And a liquid crystal layer capable of switching an alignment state by applying a voltage between the first electrode and the second electrode, and disposed on a side opposite to the side on which the liquid crystal layer is disposed on the first substrate. A first polarizing plate and a first light source disposed on the opposite side of the first polarizing plate from the side on which the first substrate is disposed; A transmission / reflection plate that transmits or reflects incident light according to the polarization state, disposed on the opposite side of the second substrate from the side where the liquid crystal layer is disposed, and the first of the transmission / reflection plate A second polarizing plate disposed on the side opposite to the side on which the second substrate is disposed, and the second polarizing plate disposed on the side opposite to the side on which the transmission / reflection plate is disposed, and emitted. A second light source having first and second emission ports capable of performing display of the first and second display units with light, respectively, and a voltage between the first electrode and the second electrode. When the voltage application means that can be applied and the period for displaying one image is one frame, one frame is time-divided into a plurality of subframes, and the first or second light source is provided in each subframe. A control circuit capable of emitting light, and the transmission / reflection plate is Reflecting light in a polarization state that transmits through the first polarizing plate and the liquid crystal layer when no voltage is applied, transmits light in a polarization state that transmits through the second polarizing plate, and transmits the light through the second polarizing plate. The light transmitted through the transmission / reflection plate and the liquid crystal layer when no voltage is applied is shielded by the first polarizing plate, and is normally black type with respect to the light emitted from the second light source. The method for driving the liquid crystal display element according to claim 1, wherein a display is performed with light emitted from the first light source in a subframe, and a light emitted from the second light source in another subframe. A method of driving a liquid crystal display element in which each display unit is displayed with light emitted from the first or second light source in at most one subframe in one frame. Provided.

  ADVANTAGE OF THE INVENTION According to this invention, the liquid crystal display element which can display various colors, and its drive method can be provided.

  The inventor of the present application proposed a liquid crystal display element having a novel structure capable of displaying various colors in Japanese Patent Application No. 2006-005156 (Japanese Patent Application No. 2006-005156, disclosure of invention [0028] stage to [0116]. Step). In the present invention, the invention according to the application is further considered.

  The inventors of the present invention have also 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 [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, a segment unit (“STANLEY R & D”) and a dot unit (in the figure, a portion represented by a square arranged in a matrix). According to the liquid crystal display device, for example, when displaying a set of “STANLEY” and “R & D” or displaying characters in a dot portion, it is possible to change the color tone in units of characters.

  For example, “STANLEY” and “R & D” segment parts are displayed. In the dot portion, one character is displayed with 20 dots in 5 rows and 4 columns in order from the left, and characters “L”, “C”, and “D” are displayed in the entire dot portion. For example, “STANLEY” and “L” are red, “C” is blue, and “R & D” and “D” are yellow. In this figure, the area displayed in color 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 twisted nematic liquid crystal layer formed of, for example, nematic liquid crystal having a positive dielectric anisotropy (Δε> 0), and is determined by the rubbing direction of the upper and lower alignment films 53a and 53b. The angle 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.

  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 dot portion and 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.

  An upper polarizing plate 54 a is disposed outside the upper substrate 50 a of the display liquid crystal cell 76. A lower polarizing plate 54 b is disposed outside the lower substrate 50 b of the area dividing liquid crystal cell 77. A central polarizing plate 54 i is disposed between the liquid crystal cells 76 and 77. 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.

  A portion constituted by the display liquid crystal cell 76, the upper polarizing plate 54a and the central polarizing plate 54i, and a portion constituted by the area dividing liquid crystal cell 77, the lower polarizing plate 54b and the central polarizing plate 54i are, for example, no. This is a Mariblack liquid crystal element.

  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 area dividing liquid crystal cell 77. The synchronization circuit 78 synchronizes the turning on / off of the multi-color backlight 56 and the application of voltage to both electrodes 52 a and 52 b of the area dividing liquid crystal cell 77 (change in the alignment state of the liquid crystal molecules in the liquid crystal layer 55). it can.

  With reference to FIG. 1C, operation of the liquid crystal display device illustrated in FIG. 1B will be described. For example, driving is performed using an FS driving method in which one frame is divided into three SBs SB1 to SB3.

  The multi-color backlight 56 emits red, blue, and yellow light in each of SB1, SB2, and SB3. 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.

  In the area dividing liquid crystal cell 77, the incident light from the multi-color backlight 56 is divided into predetermined areas (5 in areas 81 to 85 in FIG. 1C) defined on the upper substrate 50a side by the shape of the electrodes. It is possible to divide and emit for each area. That is, the electrode shape of the area dividing liquid crystal cell 77 is formed corresponding to the shapes of the areas 81 to 85.

  The area 81 is an area corresponding to a 5 × 4 region located on the left side of the dot portion shown in FIG. The letter “L” can be displayed by the light emitted from the area 81.

  Area 82 is an area corresponding to an area of 5 rows and 4 columns located in the center in the dot portion shown in FIG. The letter “C” can be displayed by the light emitted from the area 82.

  The area 83 is an area corresponding to a 5 × 4 region located on the right side of the dot portion shown in FIG. The letter “D” can be displayed by the light emitted from the area 83.

  The area 84 is an area corresponding to the character string “STANLEY” in the segment portion shown in FIG. 1A, and the character string can be displayed by the light emitted from the area 84.

  The area 85 is an area corresponding to the character string “R & D” in the segment portion shown in FIG. 1A, and the character string can be displayed by the light emitted from the area 85.

  Through the SB1 to SB3, in the display liquid crystal cell 76, among the electrodes 52a and 52b corresponding to each of the 5 rows and 4 columns on the left side, the center, and the right side of the dot portion, the segment portion that displays “STANLEY” and “R & D”, A voltage is applied between the electrodes 52a and 52b displaying the characters “L”, “C”, and “D”, respectively.

  In SB1, a voltage is applied between the electrodes 52a and 52b corresponding to the areas 81 and 84 of the area dividing liquid crystal cell 77. For this reason, among the red light emitted from the multi-color backlight 56, only the light emitted from the areas 81 and 84 is transmitted through the central polarizing plate 54i while maintaining the polarization state defined by the lower polarizing plate 54b. To do.

  Of the light transmitted through the central polarizing plate 54i, in the liquid crystal cell 76 for display, among the segments 52a and 52b corresponding to the 5 rows and 4 columns on the left side of the segment portion displaying the dot portion and the dot portion, “L Only the light that has passed through the liquid crystal layer 55 corresponding to the electrodes 52a and 52b displaying the characters "" (the red light displaying the characters "STANLEY" and "L") passes through the upper polarizing plate 54a as it is. It penetrates and reaches the eyes of the observer.

  In SB2, blue 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 areas 83 and 85 of the area dividing liquid crystal cell 77. In the display liquid crystal cell 76, the electrodes 52a and 52b for displaying the letter "D" among the segments 52 for displaying "R & D" and the electrodes 52a and 52b corresponding to 5 rows and 4 columns on the right side of the dot portion. Since a voltage is applied between them, only the blue light displaying the characters “R & D” and “D” passes through the upper polarizing plate 54a and reaches the eyes of the observer.

  In SB3, yellow 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 between the electrodes 52a and 52b displaying the letter "C" among the electrodes 52a and 52b corresponding to the 5 rows and 4 columns in the center of the dot portion. Only the yellow light displaying the characters "" passes through the upper polarizing plate 54a and reaches the eyes of the observer.

  As described above, when the liquid crystal display device according to Japanese Patent Application No. 2004-118870 is used, for example, when character display is performed with a group of segment portions or with dot portions, the color tone can be changed in units of characters.

  The outline of the liquid crystal display device according to the embodiment described in detail with reference to FIGS. 3 to 7 will be described with reference to FIGS.

  Reference is made to FIG. The liquid crystal display element 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.

  The upper substrate 50a and the lower substrate 50b are, for example, flat glass substrates (upper and lower glass substrates 51a, 51b), electrodes formed on a transparent surface such as ITO on opposite surfaces thereof, and having predetermined patterns ( Upper and lower transparent electrodes 52a and 52b) and alignment films (upper and lower alignment films 53a and 53b) formed to cover the respective electrodes.

  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.

  The liquid crystal cell 76 for display and the liquid crystal cell 77 for area division differ in the shape of an electrode. This will be described with reference to FIGS. 2B and 2C.

  An upper polarizing plate 54 a is disposed outside the upper substrate 50 a of the display liquid crystal cell 76. A lower polarizing plate 54 b is disposed outside the lower substrate 50 b of the area dividing liquid crystal cell 77. In addition, a polarized light separating / transmitting / reflecting plate 67 is disposed outside the lower substrate 50 b of the display liquid crystal cell 76. A central polarizing plate 54 i is disposed between the polarization separating / transmitting / reflecting plate 67 and the upper substrate 50 a of the area dividing liquid crystal cell 77.

  The upper polarizing plate 54a, the lower polarizing plate 54b, and the central polarizing plate 54i are, for example, a linear polarizing plate, a circular polarizing plate, or an elliptical polarizing plate. 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 case of a circularly polarizing plate and an elliptically polarizing plate, a retardation plate is further provided inside.

  The polarized light separating / transmitting / reflecting plate 67 transmits or reflects incident light according to its polarization state. As the polarized light separating transmission / reflection plate 67, for example, broadband cholesteric used in D-BEF (brightness enhance film) manufactured by 3M, Inc., brightness enhancement film PCF (polarization conversion film) manufactured by Nitto Denko Corporation, etc. A film can be used.

  In both the liquid crystal cell for display 76 and the liquid crystal cell for area division 77, a voltage at which an arbitrary voltage can be applied between the electrodes 52a and 52b between the upper transparent electrode 52a and the lower transparent electrode 52b. Application means 68 is connected. 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.

  A multi-color front light 66 and a multi-color backlight 56 are disposed outside the upper polarizing plate 54a and the lower polarizing plate 54b, respectively. The multi-color front light 66 and the multi-color backlight 56 are lights that can selectively emit light of a plurality of colors. For example, the multi-color front light 66 and the multi-color backlight 56 have RGB multi-color LED light sources on the side, Irradiate 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. The multi-color front light 66 transmits light from the liquid crystal layer.

  The multi-color backlight 56 controls display of display areas such as dots and segments. The multi-color front light 66 is used to realize color display in a non-display area.

  The synchronization circuit 78 turns on and off the multi-color backlight 56, turns on and off the multi-color front light 66, and switches the liquid crystal layer 55 of both cells 76 and 77 (changes in the alignment state of liquid crystal molecules, light-transmitting state and light-blocking state). This is a circuit for performing synchronization of switching). One frame is time-divided into a plurality of sub-frames, the multi-color front light 66 or the multi-color backlight 56 is emitted in each sub-frame, and the liquid crystal layer 55 of both cells 76 and 77 is switched in synchronization with the light emission. It can be performed.

  The portion constituted by the display liquid crystal cell 76, the upper and center polarizing plates 54a and 54i, and the polarization separation transmission / reflection plate 67 is a normally black type with respect to the light emitted from the multi-color backlight 56. It is a liquid crystal element. In addition, the portion constituted by the area dividing liquid crystal cell 77 and the central and lower polarizing plates 54 i and 54 b is normally black type or normally white type with respect to the light emitted from the multi-color backlight 56. This is a liquid crystal element.

  FIG. 2B 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 (one or a plurality of display units for performing display 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. 2C 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 divides the incident light from the multi-color backlight 56 into predetermined areas (two areas 86 and 87 in FIG. 2C) defined by the shape of the electrodes. It is possible to divide and emit. 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.

  In such a liquid crystal display element, by controlling the emission colors of the multi-color front light 66 and the multi-color backlight 56, the display area and the non-display area can be expressed separately with different color tones.

  Hereinafter, a specific configuration and operation of the liquid crystal display element will be described. In the liquid crystal display element shown in FIGS. 3 to 5, D-BEF manufactured by 3M Co., Ltd. was used as the polarization separation / transmission / reflection plate 67 in FIG. The D-BEF has a reflection axis in the in-plane direction and reflects light polarized in the reflection axis direction. Further, in the liquid crystal display element shown in FIGS. 6 and 7, the broadband cholesteric film used in the brightness enhancement film PCF manufactured by Nitto Denko Corporation as the polarization separation transmission / reflection plate 67 in FIG. It was used. The broadband cholesteric film reflects, for example, right circularly polarized light and transmits left circularly polarized light. Some broadband cholesteric films do the reverse.

  FIG. 3 is a schematic exploded perspective view showing the liquid crystal display device according to the first embodiment.

  In the display liquid crystal cell 76, the liquid crystal layer 55 is formed using a liquid crystal material having a negative dielectric anisotropy (Δε <0), thereby obtaining a vertical alignment type liquid crystal display element. The liquid crystal layer 55 of the area dividing liquid crystal cell 77 is formed of nematic liquid crystal having positive dielectric anisotropy (Δε> 0), and the twist angle is 90 °. In this figure, both cells 76 and 77 show the alignment state of the liquid crystal molecules when no voltage is applied.

  Linear polarizers were used as the upper, lower, and central polarizers 54a, 54b, 54i. The upper and central polarizing plates 54a and 54i were arranged in a crossed Nicols arrangement, and the central and lower polarizing plates 54i and 54b were arranged in a parallel Nicols arrangement. In the figure, the directions of the transmission axes of the polarizing plates 54a, 54b, 54i are indicated by arrows.

  The D-BEF 69 was arranged so that the reflection axis and the transmission axis of the upper polarizing plate 54a were parallel.

  The operation of the liquid crystal display device according to the first embodiment will be described.

  The liquid crystal molecules of the display liquid crystal cell 76 are aligned substantially perpendicular to the upper and lower substrates 50a and 50b when no voltage is applied. For this reason, the light incident on the liquid crystal layer is transmitted through the liquid crystal layer without changing the polarization direction.

  When a voltage is applied, the alignment state of the liquid crystal molecules in the non-display area is not different from that when no voltage is applied. Thus, the birefringence effect is given to the light that is inclined toward the direction of 45 ° in the in-plane direction and is incident on the liquid crystal layer. The liquid crystal layer has the same effect as the half-wave plate, and incident light is emitted from the liquid crystal layer with the polarization direction changed by 90 °.

  On the other hand, the liquid crystal molecules of the area dividing liquid crystal cell 77 are twisted by 90 ° between the upper and lower substrates 50a and 50b when no voltage is applied. For this reason, in an area where no voltage is applied, light incident on the liquid crystal layer is transmitted through the liquid crystal layer with its 90 ° polarization direction changed.

  When a voltage is applied, the liquid crystal molecules are aligned substantially vertically between the upper and lower substrates 50a and 50b. Therefore, in the area where the voltage is applied, the light incident on the liquid crystal layer passes through the liquid crystal layer without changing the polarization direction.

  First, the light emitted from the multicolor front light 66 will be described.

  The light emitted from the multicolor front light 66 enters the liquid crystal layer 55 as linearly polarized light having a polarization direction in the transmission axis direction of the upper polarizing plate 54a.

  In the non-display area (area where no voltage is applied), the light passes through the liquid crystal layer 55 without changing the polarization state, and enters the D-BEF 69. The reflection axis direction of the D-BEF 69 is parallel to the transmission axis direction of the upper polarizing plate 54a. For this reason, the light of the multi-color front light 66 that has passed through the liquid crystal layer 55 is reflected almost 100% by the D-BEF 69 and again passes through the liquid crystal layer 55 and the upper polarizing plate 54a. The transmitted light is visually recognized by an observer.

  In the display region (region to which voltage is applied), the alignment state of the liquid crystal molecules has changed since no voltage was applied, so that the light incident on the liquid crystal layer 55 changes the polarization direction by 90 ° to change the liquid crystal layer. 55 is emitted. The polarization direction of the linearly polarized light emitted from the liquid crystal layer 55 and the reflection axis direction of the D-BEF 69 are orthogonal (parallel to the transmission axis direction of the D-BEF 69). Therefore, the linearly polarized light emitted from the liquid crystal layer 55 passes through the D-BEF 69 and then the central polarizing plate 54i, propagates to the area dividing liquid crystal cell 77 side, and disappears due to scattering or the like. For this reason, the light emitted from the multi-color front light 66 is not visually recognized by the observer.

  Next, light emitted from the multicolor backlight 56 will be described.

  The light emitted from the multi-color backlight 56 becomes linearly 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.

  In an area where no voltage is applied, the light emitted from the multi-color backlight 56 changes its polarization direction by 90 ° and exits the area dividing liquid crystal cell 77, so that it is arranged in parallel with the lower polarizing plate 54b. The light is absorbed by the central polarizing plate 54i and does not enter the display liquid crystal cell 76 side.

  In the area where the voltage is applied, the light emitted from the multi-color backlight 56 is emitted from the area dividing liquid crystal cell 77 without changing the polarization direction, so that the centrally polarized light arranged in parallel with the lower polarizing plate 54b is arranged. The light passes through the plate 54 i and then the D-BEF 69 and enters the display liquid crystal cell 76.

  In the liquid crystal cell 76 for display, when a voltage is applied to an electrode at a position corresponding to an area where light from the multi-color backlight 56 is emitted, the polarization direction of the light is changed by 90 ° at the electrode position. Since the light is emitted from the display liquid crystal cell 76 and passes through the upper polarizing plate 54a, it is visually recognized by an observer.

  Accordingly, in the non-display area, the light emitted from the multi-color front light 66 can be visually recognized by the observer, and in the display area, the light emitted from the multi-color backlight 56 can be visually recognized by the observer. .

  As described above, the liquid crystal display element according to the first embodiment can independently express the color tone of the non-display area by the multi-color front light 66 and the color tone of the display area by the multi-color backlight 56. Further, by selecting the color of light emitted from the lights 56 and 66, the display colors of the display area and the non-display area can be selected, respectively.

  As described above, in the liquid crystal display element according to the first embodiment, even when the multi-color front light 66 and the multi-color backlight 56 are lit at the same time, only one light is emitted at any one place. Is visually recognized by an observer. If the liquid crystal display element performs a binary operation of ON / OFF, simultaneous lighting of both hardly causes color mixing.

  FIG. 4 is a schematic exploded perspective view showing a liquid crystal display device according to the second embodiment. In the first embodiment, a vertical alignment type liquid crystal cell is used as the display liquid crystal cell 76. In the second embodiment, a liquid crystal cell having a two-layer structure including a compensation cell (upper cell) 70 and a driving cell (lower cell) 71 disposed on the upper and central polarizing plates 54a and 54i, respectively. It differs from the liquid crystal display element according to the first embodiment in that it is used as the display liquid crystal cell 76.

  The liquid crystal layer 55 of the compensation cell 70 and the drive cell 71 are both formed using the same liquid crystal material having a positive dielectric anisotropy (Δε> 0), and each of the cells 70 and 71 has a left twist angle of 90 °. A horizontal alignment type liquid crystal display element having a right twist angle of 90 ° was obtained. The liquid crystal molecule alignment directions at the centers of the liquid crystal layers 55 of the cells 70 and 71 are orthogonal to each other, and the thicknesses of the liquid crystal layers 55 of the cells 70 and 71 are equal. This figure shows the alignment state of liquid crystal molecules when no voltage is applied.

  The display operation in the display liquid crystal cell 76 was performed only by applying a voltage to the drive cell (lower cell) 71, and no power was supplied to the compensation cell (upper cell) 70.

  The liquid crystal element composed of the compensation cell 70, the drive cell 71, the upper and center polarizing plates 54 a and 54 i, and the D-BEF 69 is a normally black liquid crystal element with respect to the light emitted from the multi-color backlight 56. is there.

  The operation of the liquid crystal display device according to the second embodiment will be described. As described above, since no power is supplied to the compensation cell 70, the liquid crystal molecules in the compensation cell 70 always maintain a left twist angle of 90 °. Therefore, the light incident on the compensation cell 70 is emitted from the compensation cell 70 with the polarization direction changed by 90 ° to the left.

  When no voltage is applied, the drive cell 71 emits incident light with the polarization direction changed 90 ° to the right. That is, in the driving cell 71, the polarization direction of light is changed by 90 ° in the opposite direction to that in the compensation cell. Therefore, the light exits the two-layer liquid crystal cell with the same polarization direction as that incident on the two-layer liquid crystal cell.

  However, when a voltage is applied, the alignment state of the liquid crystal molecules in the non-display area is not different from that when no voltage is applied, but in the display area, the alignment state of the liquid crystal molecules of the drive cell 71 changes from when no voltage is applied (upper side). And light that is incident on the drive cell 71 and is emitted from the drive cell 71 without changing the polarization direction. Therefore, the light is emitted from the liquid crystal cell having a two-layer structure with a polarization direction different by 90 ° from that incident on the liquid crystal cell having a two-layer structure.

  Therefore, the polarization direction of light is not changed by the two-layer liquid crystal cell (compensation cell 70 and drive cell 71) in the non-display region even when no voltage is applied and even when the voltage is applied. On the other hand, when a voltage is applied, in the display region, light is changed in polarization direction by 90 ° and emitted from a liquid crystal cell having a two-layer structure.

  Therefore, the liquid crystal display element according to the second embodiment operates in the same manner as the liquid crystal display element according to the first embodiment. When no voltage is applied, the liquid crystal display element is emitted from the multi-color front light 66 in the entire area of the display unit. When the voltage is applied, the light emitted from the multi-color front light 66 is visible to the observer in the non-display area, and from the multi-color backlight 56 in the display area. The light will be visually recognized by the observer.

  As a result of studying liquid crystal cells having various twist angles by the inventor of the present application, when the twist angles of the compensation cell 70 and the drive cell 71 are 70 ° to 240 °, the liquid crystal display element according to the second embodiment is practically effective. It was found to act on.

  The same effect was obtained when the compensation cell (upper cell) 70 was replaced with Twistar manufactured by Polatechno Co., Ltd., which is a liquid crystalline polymer alignment phase difference plate having an optical function equivalent to this.

  FIG. 5 is a schematic exploded perspective view showing a liquid crystal display device according to the third embodiment.

  The liquid crystal display element according to the third embodiment is a liquid crystal display element including a retardation plate 72 between the upper substrate 50a and the upper polarizing plate 54a of the display liquid crystal cell 76.

  By appropriately determining the twist angle of the liquid crystal molecules, the thickness of the liquid crystal layer, the retardation value of the retardation plate, and the orientation of the slow axis, the upper and lower substrates 50a and 50b, the liquid crystal layer 55, the upper and central polarizations The liquid crystal element composed of the plates 54a and 54i, the D-BEF 69, and the phase difference plate 72 was a normally black type liquid crystal element with respect to the light emitted from the multi-color backlight 56. Here, the phase difference plate 72 plays a role of adjusting the color tone.

  Details of the configuration are as follows.

  The thickness of the liquid crystal layer 55 of the liquid crystal cell for display 76 was 6 μm, and RDP00333 manufactured by Dainippon Ink, Inc. was used as the liquid crystal material. The liquid crystal molecules had a twisted horizontal orientation with a twist angle of 240 ° to the left. As the retardation plate 72, a uniaxial optically anisotropic retardation plate having a retardation value of 600 nm was used. Further, the slow axis of the retardation film 72, the transmission axis of the upper polarizing plate 54a, the transmission axis of the D-BEF 69, and the transmission axis of the central polarizing plate 54i are respectively in the thickness direction of the liquid crystal layer 55 of the display liquid crystal cell 76. The angles formed with the central molecular orientation direction were 140 °, 95 °, 70 °, and 70 °.

  This figure shows the alignment state of liquid crystal molecules when no voltage is applied. Moreover, the direction of the transmission axis of the upper and central polarizing plates 54a and 54i, the direction of the slow axis of the phase difference plate 72, and the direction of the transmission axis of the D-BEF 69 are indicated by arrows.

  In the liquid crystal display device according to the third embodiment, the liquid crystal layer 55 of the area dividing liquid crystal cell 77 is formed using a liquid crystal material having negative dielectric anisotropy (Δε <0), and is vertically aligned. Liquid crystal cell. The center and lower polarizing plates 54i and 54b are arranged in a crossed Nicols arrangement.

  In the third embodiment, one retardation plate 72 is used, but a plurality of retardation plates can also be used. Further, not only a uniaxial optically anisotropic phase difference plate, but also a biaxial optically anisotropic phase difference plate may be used.

  The twist angle of the liquid crystal molecules in the display liquid crystal cell 76 is preferably 180 ° to 240 °.

  FIG. 6 is a schematic exploded perspective view showing a liquid crystal display device according to the fourth embodiment.

  The liquid crystal display element according to the fourth embodiment is similar to the liquid crystal display element according to the first embodiment shown in FIG. In the liquid crystal display element according to the first embodiment, the upper and center polarizing plates 54a and 54i are arranged on the outer sides of the upper and lower substrates 50a and 50b that sandwich the liquid crystal layer 55 of the display liquid crystal cell 76, respectively. Then, D-BEF was inserted between the lower substrate 50b and the central polarizing plate 54i as a polarization separation transmission / reflection plate that transmits or reflects incident light according to its polarization state.

  In the liquid crystal display device according to the fourth embodiment, first, as the polarization separating / transmitting / reflecting plate 67, a broadband cholesteric film instead of D-BEF is used between the lower substrate 50b of the display liquid crystal cell 76 and the central polarizing plate 54i. The liquid crystal display device according to the first embodiment is different from the liquid crystal display device according to the first embodiment.

  In the liquid crystal display element according to the first embodiment, linearly polarizing plates are used as the upper and central polarizing plates 54a and 54i. However, in the liquid crystal display element according to the fourth embodiment, as the upper polarizing plate 54a, A circularly polarizing plate for light from above, which is a combination of the upper linear polarizing plate 54e and the upper quarter-wave plate 54g, is adopted. As the central polarizing plate 54i, the central linear polarizing plate 54f and the central quarter-wave plate 54h are used. A circularly polarizing plate with respect to light from below was employed. The upper and center polarizing plates 54a and 54i are both formed by disposing a quarter-wave plate on the display liquid crystal cell 76 side, and the transmission axis of the linear polarizing plate and the slow axis of the quarter-wave plate. The angle formed by was set to ± 45 °. The transmission axes of the upper and central linearly polarizing plates 54e and 54f were orthogonal to each other. However, the orientations of the transmission axes of the upper and central linear polarizing plates 54e and 54f may be arbitrary with respect to the upper and lower substrates 50a and 50b.

  Further, the functions of the quarter wavelength plates 54g and 54h may be realized by using a combination of a plurality of wavelength plates (for example, a combination of a quarter wavelength plate and a half wavelength plate).

  The lower polarizing plate 54b is a linear polarizing plate, and the transmission axes of the central and lower linear polarizing plates 54f and 54b are parallel to each other.

  In the liquid crystal display device according to the fourth embodiment, the upper polarizing plate 54a is a right circular polarizing plate, and the central polarizing plate 54i is a left circular polarizing plate. The broadband cholesteric film 73 reflects right circularly polarized light and transmits left circularly polarized light.

  Hereinafter, circularly polarized light whose x component is retarded with respect to the y component is right-circularly polarized light, and circularly polarized light whose phase is fast is left-circularly polarized light.

  On the contrary, the upper polarizing plate 54a may be a left circular polarizing plate, the central polarizing plate 54i may be a right circular polarizing plate, the broadband cholesteric film 73 may reflect left circular polarized light and transmit right circular polarized light. The circular polarization directions of the upper polarizing plate 54a and the central polarizing plate 54i are reversed, and the circular polarization direction transmitted through the broadband cholesteric film 73 and the circular polarizing direction of the central polarizing plate 54i are matched.

  In addition, NITOCS manufactured by Nitto Denko Corporation and TRANSMAX manufactured by Merck Co., Ltd., which adopt a configuration in which a broadband cholesteric film and a circularly polarizing plate are bonded together, are usually bonded to the backlight or the lower side of the liquid crystal cell. Used. In this case, the broadband cholesteric film is disposed on the light side (the side opposite to the liquid crystal cell). This embodiment is different from this in that the broadband cholesteric film is disposed on the liquid crystal cell side.

  The liquid crystal layer 55 of the display liquid crystal cell 76 is formed using a liquid crystal material having a negative dielectric anisotropy (Δε <0) to form a vertical alignment type liquid crystal cell. This figure shows the alignment state of liquid crystal molecules when no voltage is applied. Further, the retardation of the liquid crystal layer 55 at the time of voltage application was set to ½ wavelength (for example, the x component was ½ wavelength delayed phase).

  The light emitted from the multi-color front light 66 is polarized in the transmission axis direction of the upper linear polarizing plate 54e and enters the upper quarter wavelength plate 54g, and the x component is delayed by a quarter wavelength. Becomes right circularly polarized light.

  When no voltage is applied to the display liquid crystal cell 76, the light incident on the liquid crystal layer 55 of the display liquid crystal cell 76 is emitted from the liquid crystal layer 55 without changing the polarization state. The right circularly polarized light emitted from the multi-color front light 66 and emitted from the upper quarter-wave plate 54 g is emitted from the liquid crystal layer 55 as right circularly polarized light and reflected by the broadband cholesteric film 73. The reflected light passes through the liquid crystal layer 55 of the display liquid crystal cell 76 as right circularly polarized light, and the y component undergoes a quarter wavelength retardation by the upper quarter wavelength plate 54g. For this reason, it becomes linearly polarized light having the same polarization component as the incident light, is transmitted by the upper linear polarizing plate 54e, and is visually recognized by the observer. Conversely, the light emitted from the multi-color backlight 56, divided for each area by the area dividing liquid crystal cell 77, and transmitted through the central linear polarizing plate 54f has an x component of 1/4 at the central quarter-wave plate 54h. It receives the wavelength advance, passes through the liquid crystal layer as left circularly polarized light, and receives the 1/4 wavelength retarded phase by the upper quarter wavelength plate 54g, so that it becomes linearly polarized light with the polarization axis of the central polarizing plate rotated by 90 °, It is shielded by the upper linear polarizing plate 54e and is not visually recognized by an observer.

  When a voltage is applied to the display liquid crystal cell 76, the alignment state of the liquid crystal molecules in the liquid crystal layer 55 of the display liquid crystal cell 76 changes, so that the right circularly polarized light incident on the liquid crystal layer 55 in the display region becomes left circularly polarized light. The liquid crystal layer 55 is emitted. The left circularly polarized light becomes right circularly polarized light and exits the liquid crystal layer 55.

  The light emitted from the multi-color front light 66 is visually recognized by the observer in the non-display area in the same manner as when no voltage is applied to the display liquid crystal cell 76. In the display area, the x component is delayed by 1/4 wavelength and 1/2 wavelength, and becomes left circularly polarized light, transmitted through the broadband cholesteric film 73, and 1/4 wavelength by the lower 1/4 wavelength plate 54h. The phase is advanced and transmitted through the lower linear polarizing plate 54f, so that it is not visually recognized by an observer.

  On the other hand, the light emitted from the multi-color backlight 56, divided for each area by the area dividing liquid crystal cell 77, and transmitted through the central linear polarizing plate 54f is the central quarter wavelength plate 54h, the liquid crystal layer 55, the upper 1 / The 4-wavelength plate 54g receives the 1/4 wavelength phase advance, 1/2 wavelength retarded phase, and 1/4 wavelength retarded phase, and enters the upper linear polarizing plate 54e. Is done.

  The liquid crystal element composed of the display liquid crystal cell 76, the upper and center polarizing plates 54a and 54i, and the broadband cholesteric film 73 is a normally black liquid crystal element for the light emitted from the multi-color backlight 56. . In addition, although a retardation plate (retardation film) such as a viewing angle compensation plate was not used between the display liquid crystal cell 76 and the upper or central polarizing plates 54a and 54i, it should be used as needed. Is also possible.

  The operation of the liquid crystal display element according to the fourth embodiment is the same as that of the liquid crystal display element according to the first embodiment. Therefore, when no voltage is applied to the display liquid crystal cell 76, the light emitted from the multi-color front light 66 is visually recognized by the observer in the entire area of the display unit, and when the voltage is applied to the display liquid crystal cell 76. In the non-display area, the light emitted from the multi-color front light 66 can be visually recognized by the observer, and in the display area, the light emitted from the multi-color backlight 56 can be visually recognized by the observer.

  The liquid crystal display element according to the fourth embodiment can achieve the same effects as the liquid crystal display element according to the first embodiment.

  FIG. 7 is a schematic exploded perspective view showing a liquid crystal display device according to a fifth embodiment. In the fourth embodiment, a vertical alignment type liquid crystal cell is used as the display liquid crystal cell 76. In the fifth embodiment, a two-layer structure including a twisted nematic compensation cell (upper cell) 70 and a twisted nematic driving cell (lower cell) 71 disposed on the upper and central polarizing plates 54a and 54i, respectively. This is different from the liquid crystal display device according to the fourth embodiment in that the twisted nematic liquid crystal cell is used.

  The liquid crystal layer 55 of the compensation cell 70 and the drive cell 71 are both formed using the same liquid crystal material having a positive dielectric anisotropy (Δε> 0), and each of the cells 70 and 71 has a left twist angle of 90 °. A horizontal alignment type liquid crystal display element having a right twist angle of 90 ° was obtained. The liquid crystal molecule alignment directions at the centers of the liquid crystal layers 55 of the cells 70 and 71 are orthogonal to each other, and the thicknesses of the liquid crystal layers 55 of the cells 70 and 71 are equal. This figure shows the alignment state of liquid crystal molecules when no voltage is applied. The retardation of the liquid crystal layer 55 of both cells 70 and 71 is set to one wavelength.

  The display operation of the display liquid crystal cell 76 was performed only by applying a voltage to the drive cell (lower cell) 71, and no power was supplied to the compensation cell (upper cell) 70.

  The liquid crystal element composed of the compensation cell 70, the drive cell 71, the upper and center polarizing plates 54 a and 54 i, and the broadband cholesteric film 73 is a normally black liquid crystal element for the light emitted from the multi-color backlight 56. It is.

  The operation of the liquid crystal display device according to the fifth embodiment will be described. As described above, since the compensation cell 70 is not energized, the compensation cell 70 functions as a polarization rotator. Accordingly, the right circularly polarized light incident on the compensation cell 70 becomes left circularly polarized light and exits from the compensation cell 70. The left circularly polarized light becomes right circularly polarized light and exits from the compensation cell 70.

  The drive cell 71 functions as a polarization rotator that exhibits a rotation direction opposite to that of the compensation cell when no voltage is applied. The same applies to the non-display area even when the voltage is applied. However, in the display region, the alignment state of the liquid crystal molecules of the driving cell 71 changes from when no voltage is applied (aligned substantially perpendicularly to the upper and lower substrates 50a and 50b), and the light incident on the driving cell 71 is in the polarization state. The light is emitted from the drive cell 71 without changing.

  Accordingly, when no voltage is applied to the driving cell 71 and even when the voltage is applied, in the non-display region, the light incident on the liquid crystal cell having the two-layer structure (the compensation cell 70 and the driving cell 71) is right circularly polarized light. Then, the liquid crystal cell having a two-layer structure is emitted as it is with right circular polarization and with left circular polarization as left circular polarization. On the other hand, when a voltage is applied, in the display region, the right circularly polarized light becomes left circularly polarized light, and the left circularly polarized light becomes right circularly polarized light and is emitted from the liquid crystal cell having a two-layer structure.

  Therefore, the liquid crystal display element according to the fifth embodiment operates in the same manner as the liquid crystal display element according to the fourth embodiment. When no voltage is applied to the drive cell 71, the multi-color front element is used in the entire area of the display section. The light emitted from the light 66 is visually recognized by the observer, and when the voltage is applied to the drive cell 71, the light emitted from the multicolor front light 66 is visually recognized by the observer in the non-display area, and in the display area. The light emitted from the multi-color backlight 56 can be visually recognized by the observer.

  As a result of studying liquid crystal cells having various twist angles by the inventor of the present application, when the twist angles of the compensation cell 70 and the drive cell 71 are 70 ° to 240 °, the liquid crystal display element according to the fifth embodiment is practically effective. It was found to act on.

  The same effect was obtained when the compensation cell (upper cell) 70 was replaced with Twistar manufactured by Polatechno Co., Ltd., which is a liquid crystalline polymer alignment phase difference plate having an optical function equivalent to this.

  As mentioned above, although demonstrated along the Example, the liquid crystal display element which concerns on this invention is not limited to these Examples. For example, FIGS. 4 and 7 illustrate a liquid crystal display device in which the upper and lower substrates 50a and 50b of the compensation cell 70 include upper and lower transparent electrodes 52a and 52b, respectively, but no voltage is applied to the compensation cell 70. If these are not necessary. In the embodiment, the compensation cell 70 is arranged on the upper side and the driving cell 71 is arranged on the lower side. However, these arrangements may be reversed.

  In the embodiments, the liquid crystal display element capable of performing both segment display and dot display has been described. However, a segment type liquid crystal display element or a full dot type liquid crystal display element may be used.

  The retardation plate (retardation film) can be inserted between one or both of the upper substrate 50a and the upper polarizing plate 54a and between the lower substrate 50b and the central polarizing plate 54i.

  With reference to FIGS. 8A and 8B, a driving method of the liquid crystal display element according to the embodiment will be described. The liquid crystal display element to be driven is, for example, the liquid crystal display element described with reference to FIGS. These liquid crystal display elements are provided with a display portion as shown in FIG. An area as shown in FIG. 2C is defined on the upper substrate side of the dividing liquid crystal cell.

  In the driving method according to the embodiment, one frame is set to 16.7 ms and divided into three SBs (SB1 to SB3) each having 5.57 ms. The first 3 ms of each SB was set as a blank period, and the remaining 2.57 ms was set as a light emission period.

  FIG. 8A is a table showing application / non-application of voltage to the electrodes of a display liquid crystal cell (or a drive cell when the display liquid crystal cell has a two-layer structure). 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 SB1 to SB3, and “OFF” indicates that no voltage is applied through SB1 to SB3.

  Of the electrodes corresponding to the 20 dots of the dots 88a to 88u, the voltage was applied to the electrodes corresponding to the 8 dots of the dots 88a to 88e, 88j, 88p, and 88u, and the electrodes to which the voltage was applied When dots corresponding to are connected, an “L” shape is formed. A voltage was also applied to the electrode corresponding to the segment 89 displaying “ST”. The dots forming the “L” shape and the “ST” segment are display areas, and the remaining non-display areas and background areas are non-display areas.

  FIG. 8B is a table summarizing application / non-application of voltage to the area dividing liquid crystal cell, turning on / off of the multi-color front light, and turning on / off of the multi-color backlight.

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

  In addition, for the columns of the multi-color front light and the multi-color backlight, “ON” indicates lighting and “OFF” indicates extinguishing. The lighting color is written in parentheses next to “ON”. Also, both lights were not turned on simultaneously.

  The switching of the liquid crystal layer of the multi-color front light, the multi-color backlight, and the area dividing liquid crystal cell was synchronized using a synchronization circuit. Thereby, the color mixture of the illumination light in a display part can be avoided.

  Refer to the row of SB1. In SB1, blue light was emitted from the multicolor front light. The multi-color backlight was turned off and no light was emitted. In the area dividing liquid crystal cell, no voltage was applied to both areas 86 and 87.

  Since no light is emitted from the areas 86 and 87 of the area dividing liquid crystal cell, voltage is applied to the electrodes corresponding to the dots forming the “L” shape of the liquid crystal cell for display and the segment displaying “ST”. However, those parts (display areas) are not displayed.

  On the other hand, blue light from the multi-color front light is incident on the non-display area.

  Refer to the row of SB2. In SB2, the multi-color front light was turned off and no light was emitted. Also, red light was emitted from the multicolor backlight. In the area dividing liquid crystal cell, a voltage was applied to the electrode corresponding to the area 86, and no voltage was applied to the area 87.

  Red light is emitted from the area 86 of the area dividing liquid crystal cell, but no light is emitted from the area 87. The area 86 is demarcated in correspondence with the electrode formation positions corresponding to the dots 88a to 88u, and the light emitted from the area 86 is used for displaying the dots 88a to 88u. Therefore, the dots forming the “L” shape of the display liquid crystal cell to which a voltage is applied are displayed by the red light emitted from the area 86.

  Refer to the row of SB3. In SB3, the multi-color front light was turned off and no light was emitted. In addition, yellow light was emitted from the multi-color backlight. In the area dividing liquid crystal cell, no voltage was applied to the electrode corresponding to the area 86, and a voltage was applied to the area 87.

  Yellow light is emitted from the area 87 of the area dividing liquid crystal cell, but no light is emitted from the area 86. The area 87 is demarcated corresponding to the position where the electrode corresponding to the segment 89 is formed, and the light emitted from the area 87 is used to display the segment 89. For this reason, the “ST” segment of the display liquid crystal cell to which a voltage is applied is displayed by the yellow light emitted from the area 87.

  When the inventor of the present application drives each liquid crystal display element according to the embodiment by the driving method shown in FIGS. 8A and 8B, the “L” due to the dots is displayed in the display portion as shown in FIG. In red, “ST” by the segment was displayed in yellow, and the other part (non-display area) was displayed in blue.

  In the driving method of the liquid crystal display element according to the embodiment, in SB1, the multi-color front light is turned on to express the non-display area. In SB2 and SB3, the multi-color backlight 56 was turned on to express the display area. Since the lighting colors of SB1, SB2, and SB3 were blue, red, and yellow, respectively, the non-display area was expressed in blue, and the display area was expressed in red and yellow.

  Since the multi-color front light and the multi-color backlight can emit light of an arbitrary color, various color displays can be performed in both the display area and the non-display area. Further, as shown in the embodiment, the display area can be displayed in a plurality of colors. For example, if three SBs for displaying the display area are provided and light of different colors is emitted from the multi-color backlight in each SB, the display area can be displayed in three colors. Therefore, depending on the number of display units, display in a different color for each display unit is also possible.

  Since the display liquid crystal cell is normally black, the background area can be displayed in black by turning off the multicolor front light through all the SBs. Further, a display unit (for example, one dot) can be displayed in black by controlling using a synchronizing circuit so that display with illumination light is not performed through all SBs. . For this reason, when one frame is divided into n SBs including SBs for expressing non-display areas, display in n + 1 colors including non-display area colors is possible.

  Furthermore, since each display unit and the background area are displayed with light from the light only in at most one SB, a color break can be prevented.

  Further, as can be understood from the driving method described with reference to FIGS. 8A and 8B, it is not always necessary to use a liquid crystal cell that responds quickly to light emission as a display liquid crystal cell. . 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 is required to have a high-speed response, it is preferable that the area dividing liquid crystal cell has a low duty, particularly a static drive. Since the area dividing liquid crystal cell is configured with a smaller number of pixels than the display liquid crystal cell, it can be easily formed as a static drive cell.

  Further, it is not essential that the display liquid crystal cell, the area dividing liquid crystal cell, the multi-color front light, and the multi-color backlight are all synchronized.

  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.

(A)-(C) are the figures for demonstrating simply regarding the liquid crystal display device based on Japanese Patent Application No. 2004-118870. (A)-(C) are the figures for demonstrating the outline of the liquid crystal display element by the Example explained in full detail with reference to FIGS. 1 is a schematic exploded perspective view showing a liquid crystal display element according to a first embodiment. It is a schematic exploded perspective view which shows the liquid crystal display element by a 2nd Example. It is a schematic exploded perspective view which shows the liquid crystal display element by a 3rd Example. It is a schematic exploded perspective view which shows the liquid crystal display element by a 4th Example. It is a schematic exploded perspective view which shows the liquid crystal display element by a 5th Example. (A) And (B) is a figure for demonstrating the drive method of the liquid crystal display element by an Example. (A)-(C) are schematic exploded perspective views which show the example of an internal structure of the liquid crystal display element which can adjust the color tone of a non-display area | region. (A) And (B) is a schematic exploded perspective view which shows the internal structural example of the liquid crystal display element which can adjust the color tone of a dot part or a segment part. (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 liquid-crystal drive method 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 54c Upper color polarizing plate 54d Lower color polarizing plate 54e Upper linear polarizing plate 54f Central linear polarizing plate 54g Upper quarter wavelength plate 54h Central quarter wavelength plate 54i Central polarizing plate 55 Liquid crystal layer 56 Multi-color back Light 57 White backlight 58 Phase difference plate 59 Black mask 60 Area color filter 60r Red portion 60g Green portion 60b Blue portion 60w White portion 66 Multi-color front light 67 Polarization separation transmission / reflection plate 68 Voltage application means 69 D-BEF
70 Compensation cell 71 Drive cell 72 Phase difference plate 73 Broadband cholesteric film 75 Backlight synchronous drive circuit 76 Display liquid crystal cell 77 Area division liquid crystal cell 78 Synchronous circuit 81-87 Area 88a-88u Dot 89 Segment 90 Background area

Claims (16)

A first substrate provided with a first electrode of a predetermined shape;
A second substrate having a second electrode having a predetermined shape and arranged substantially parallel to the first substrate, wherein the first electrode and the second electrode are opposed to each other. A plurality of display units including a first display unit and a second display unit are defined, and a second substrate in which a background region is defined at a position where the first electrode and the second electrode do not face each other;
A liquid crystal layer disposed between the first substrate and the second substrate and capable of switching an alignment state by applying a voltage between the first electrode and the second electrode; ,
A first polarizing plate disposed on a side of the first substrate opposite to the side on which the liquid crystal layer is disposed;
A first light source disposed on the opposite side of the first polarizing plate from the side on which the first substrate is disposed;
A transmitting / reflecting plate that transmits or reflects incident light according to a polarization state, disposed on the side opposite to the side on which the liquid crystal layer is disposed of the second substrate;
A second polarizing plate disposed on a side opposite to the side on which the second substrate of the transmission / reflection plate is disposed;
The first and second display units are arranged on the opposite side of the second polarizing plate from the side on which the transmission / reflection plate is arranged, and can perform display of the first and second display units with the emitted light, respectively. A second light source comprising two exit ports;
Voltage applying means capable of applying a voltage between the first electrode and the second electrode;
When a period for displaying one image is one frame, a control circuit capable of time-dividing one frame into a plurality of subframes and causing the first or second light source to emit light within each subframe is provided. And
The transmissive / reflecting plate reflects light in a polarized state that passes through the first polarizing plate and the liquid crystal layer when no voltage is applied, and transmits light in a polarized state that passes through the second polarizing plate. ,
The light transmitted through the second polarizing plate, the transmission / reflection plate, and the liquid crystal layer when no voltage is applied is blocked by the first polarizing plate and is emitted from the second light source. In contrast, a normally black liquid crystal display element.   The liquid crystal display element according to claim 1, wherein the first or second light source can selectively emit light of a plurality of colors.   The first polarizing plate and the second polarizing plate are linear polarizing plates each having a transmission axis in a first direction and in a second direction orthogonal to the first direction. A liquid crystal display element according to 1.   The liquid crystal display element according to claim 3, wherein the direction of the reflection axis of the transmission / reflection plate is parallel to the first direction.   The first polarizing plate is a circular polarizing plate that transmits right circularly polarized light, and the second polarizing plate is a circular polarizing plate that transmits left circularly polarized light, or the first polarizing plate is left circularly polarized light. The liquid crystal display element according to claim 1, wherein the second polarizing plate is a circularly polarizing plate that transmits right-handed circularly polarized light.   The liquid crystal display element according to claim 5, wherein each of the first and second polarizing plates includes a linear polarizing plate and a quarter-wave plate.   The liquid crystal display element according to claim 1, wherein the liquid crystal layer is vertically aligned and sandwiched between the first substrate and the second substrate in a state where no voltage is applied. And a compensation liquid crystal layer disposed between the second substrate and the transmission / reflection plate or between the first substrate and the first polarizing plate,
The liquid crystal layer and the compensation liquid crystal layer include liquid crystal molecules that are twisted and horizontally aligned in opposite directions with no voltage applied thereto,
The alignment direction of the liquid crystal molecules located in the center of the thickness direction of the liquid crystal layer is orthogonal to the alignment direction of the liquid crystal molecules located in the center of the thickness direction of the compensation liquid crystal layer,
The liquid crystal display element according to claim 1, wherein the liquid crystal layer and the compensation liquid crystal layer have the same retardation.   The liquid crystal display element according to claim 8, wherein a twist angle of liquid crystal molecules of the liquid crystal layer and the compensation liquid crystal layer is 70 ° to 240 °.   Furthermore, it contains the phase difference plate arrange | positioned between the said 1st board | substrate and the said 1st polarizing plate, or between the said 2nd board | substrate and the said 2nd polarizing plate. The liquid crystal display element according to any one of the above. The second light source includes a light emitting device and a liquid crystal cell into which light emitted from the light emitting device is incident,
The liquid crystal cell is
A third substrate provided with a third electrode of a predetermined shape;
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 positioned at positions where the third electrode and the fourth electrode are opposed to each other. A fourth substrate on which an emission port including one emission port and a second emission port is defined;
The liquid crystal display element of any one of Claims 1-10 comprised including the liquid crystal layer pinched | interposed between the said 3rd board | substrate and the said 4th board | substrate.   The liquid crystal display element according to claim 11, wherein the control circuit synchronizes light emission of the light emitting device and switching of an alignment state of the liquid crystal layer between the third and fourth substrates.   The control circuit performs display with light emitted from the first light source in a certain subframe, performs display with light emitted from the second light source in another subframe, and displays the display. Each of the units is configured to display light from the first light source and the second light source so that display is performed with light emitted from the first or second light source in at most one subframe in one frame. The liquid crystal display element of any one of Claims 1-12 which controls light emission of a light source.   14. The control circuit according to claim 1, wherein the control circuit controls the first or second light source to emit light of different colors in all subframes in one frame. Liquid crystal display element. A first substrate provided with a first electrode of a predetermined shape; and a second substrate provided with a second electrode of a predetermined shape arranged substantially parallel to the first substrate, wherein the first substrate A plurality of display units including a first display unit and a second display unit that perform display at a position where the electrodes of the second electrode and the second electrode face each other are defined, and the first electrode and the second electrode face each other A second substrate in which a background region is defined at a position not to be disposed, and between the first substrate and the second substrate, and a voltage is applied between the first electrode and the second electrode. A liquid crystal layer whose orientation state can be switched by applying, a first polarizing plate disposed on a side opposite to the side on which the liquid crystal layer is disposed on the first substrate, and the first polarized light. A first light source disposed on a side of the plate opposite to the side on which the first substrate is disposed, and the liquid crystal layer on the second substrate is disposed The transmitting / reflecting plate that transmits or reflects incident light according to the polarization state is opposite to the side where the second substrate of the transmitting / reflecting plate is disposed. A second polarizing plate disposed on the side of the second polarizing plate, and a second polarizing plate disposed on the opposite side of the second polarizing plate from the side on which the transmission / reflection plate is disposed. A second light source having first and second emission ports capable of displaying a unit; a voltage applying means capable of applying a voltage between the first electrode and the second electrode; A control circuit capable of time-dividing one frame into a plurality of sub-frames and causing the first or second light source to emit light within each sub-frame when a period for displaying one image is one frame. The transmissive / reflecting plate includes the first polarizing plate and no voltage. Reflects light in a polarization state that passes through the liquid crystal layer, transmits light in a polarization state that passes through the second polarizing plate, and applies the second polarizing plate, the transmission / reflection plate, and no voltage application. The light transmitted through the liquid crystal layer at the time is a method of driving a normally black type liquid crystal display element with respect to the light emitted from the second light source, which is shielded by the first polarizing plate,
In a subframe, displaying with the light emitted from the first light source;
Displaying in the other sub-frame with the light emitted from the second light source, and each of the display units includes the first or second light source in at most one sub-frame in one frame. A driving method of a liquid crystal display element in which display is performed with light emitted from the liquid crystal display.   16. The method for driving a liquid crystal display element according to claim 15, wherein the control circuit controls the first or second light source to emit light of different colors in all subframes in one frame. .

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