JP5052933B2 - Liquid crystal display element, projection display device using the same, and driving method thereof - Google Patents

Description

  The present invention relates to a liquid crystal display element, a projection display apparatus using the same, and a driving method thereof, and more particularly to a field sequential (FS) drive type liquid crystal display element (LCD), a projection display apparatus using the same, and each The present invention relates to a driving method.

  In a liquid crystal display element, generally, a display with white display on a black background is called negative display, and a display with black display on a white background is called positive display.

  Field sequential (FS) driving method as a driving method of a color display liquid crystal display element that displays a color other than white on a black background in negative display or a color display liquid crystal display element that displays a color other than black on a white background in positive display It has been known. Patent Documents 1 to 4 propose FS drive type liquid crystal display elements in which the display segment is a color other than black and white.

  In the use of FSLCD, a so-called time division color mixing method is generally used. In this case, for example, when the surrounding environment is dark or the LCD vibrates, or when the observer's line of sight moves at high speed, each color display state is observed separately in human eyes during mixed color display, so-called color break phenomenon And the display quality is significantly reduced.

  Patent Document 5 proposes an FS drive (hereinafter referred to as a color breakless drive method) liquid crystal display element that performs arbitrary color display for both the display segment and the background color and does not cause a color break.

Japanese Patent Laid-Open No. 11-085062 JP 2004-029154 A JP 2004-294824 A JP 2002-303846 A JP 2006-330612 A

  In the case of the liquid crystal display element described in Patent Document 5, two liquid crystal cells are used. One liquid crystal cell displays a normal segment display, and the other liquid crystal cell displays a so-called reverse pattern. The two liquid crystal cells and the backlight are driven synchronously so that the backlight color is transmitted through only one subframe among the plurality of subframes. Therefore, in the color breakless driving method, colors that can be displayed are limited.

  In the color breakless driving method, the number of simultaneously displayed colors is determined by the number of subframe divisions of one frame.

  Assuming driving at a general frame frequency of 60 Hz, one frame is about 16.7 ms. By dividing this frame, a display color corresponding to the number of divisions can be obtained. However, the division of the frame is practically limited to about 3 due to the limit of the response speed of currently used liquid crystal materials.

  When the number of divided frames is 3, four-color display is possible including black in a light-shielded state. In this case, it is possible to assign arbitrary colors to the three colors other than black by controlling the backlight unit, but the simultaneous display color cannot exceed 4 including black.

  Further, when an arbitrary color can be displayed as the background color, it is necessary to assign one of the four colors for the background, and the number of simultaneously used colors in the area where dots, designs, etc. are displayed is further limited.

  An object of the present invention is to provide a liquid crystal display element that compensates for the small number of display colors and can simultaneously increase the number of display colors without degrading display quality, a projection display device using the liquid crystal display element, and a driving method thereof. It is to be.

According to one aspect of the present invention, a first pair of substrates facing each other and a first liquid crystal layer held between the first pair of substrates, the first pair of substrates being a predetermined pair A first liquid crystal comprising at least a pair of first pixel electrodes for displaying the characters and figures, and capable of controlling an alignment state of the first liquid crystal layer by adjusting a voltage applied to the first pixel electrodes. A cell, a second pair of substrates opposed to each other, and a second liquid crystal layer held between the second pair of substrates, wherein the second pair of substrates is a portion of the first liquid crystal cell. A second liquid crystal having a second pixel electrode that completely includes a predetermined character or figure, and capable of controlling an alignment state of the second liquid crystal layer by adjusting a voltage applied to the second pixel electrode; Cell and a layered structure panel including the first and second liquid crystal cells arranged on both sides with respect to the normal direction of the substrate. Two cross-polarizers, a light source capable of light emission of multiple colors, one frame is time-divided into multiple sub-frames, light of a predetermined color is emitted within each sub-frame, and the light emission is synchronized And a control circuit for controlling light transmission and light shielding states of a plurality of pixel regions of the structure including the first and second liquid crystal cells, and the first liquid crystal cell and the second liquid crystal cell. The twist angles of the liquid crystal molecules in the liquid crystal layer in the liquid crystal layer are equal, the orientation direction of the liquid crystal layer center molecule in the first liquid crystal cell is orthogonal to the orientation direction of the liquid crystal layer center molecule in the second liquid crystal cell, and The retardation (Δnd) of the liquid crystal layer in each of the first liquid crystal cell and the second liquid crystal cell is equal, and the electrode formed in the first liquid crystal cell and the second liquid crystal cell formed in the second liquid crystal cell Defined by pixel electrodes When both the first liquid crystal cell and the second liquid crystal cell defining each predetermined display area are in a driving state or a non-driving state, each of the display areas is in a light shielding state, and the first, There is provided a liquid crystal display element that performs gradation display by controlling the alignment state of the liquid crystal layer of at least one liquid crystal cell of the second liquid crystal cell to a drive state intermediate between a drive state and a non-drive state.

According to another aspect of the present invention, a first pair of substrates facing each other and a first liquid crystal layer held between the first pair of substrates, wherein the first pair of substrates includes: A first pixel electrode that includes at least a pair of first pixel electrodes that display predetermined characters and graphics, and that can control an alignment state of the first liquid crystal layer by adjusting a voltage applied to the first pixel electrode. A liquid crystal cell; a second pair of substrates facing each other; and a second liquid crystal layer held between the second pair of substrates, wherein the second pair of substrates is the first liquid crystal cell. A second pixel electrode that completely includes the predetermined characters and figures in FIG. 2, and a second voltage that can control an alignment state of the second liquid crystal layer by adjusting a voltage applied to the second pixel electrode. On both sides with respect to the normal direction of the substrate in a layer structure panel including a liquid crystal cell and the first and second liquid crystal cells Two cross-polarizers installed, a light source capable of emitting a plurality of colors, and a frame divided into a plurality of sub-frames to emit light of a predetermined color within each sub-frame, by synchronizing have a control circuit for controlling the state of permeability light and shielding of a plurality of pixel areas of the structure including the first and second liquid crystal cell, the second liquid crystal and the first liquid crystal cell The twist angles of the liquid crystal molecules of the liquid crystal layer in the cell are equal, and the orientation direction of the center molecule of the liquid crystal layer in the first liquid crystal cell is orthogonal to the orientation direction of the center molecule of the liquid crystal layer in the second liquid crystal cell, A method of driving a liquid crystal display element in which the retardation (Δnd) of the liquid crystal layer in the first liquid crystal cell and the second liquid crystal cell is the same, wherein at least one of the first and second liquid crystal cells Alignment of liquid crystal layer There is provided a driving method of a liquid crystal display element that performs gradation display by controlling the state to a driving state intermediate between a driving state and a non-driving state.

  Multi-color display is possible while maintaining the display quality of the FS drive type liquid crystal display element.

  FIG. 1 is a cross-sectional view of a liquid crystal display unit 101 which is a main part of a liquid crystal display element according to an embodiment. Here, an example using a TN (twisted nematic) liquid crystal cell will be described. As shown in the drawing, the liquid crystal display unit 101 according to the embodiment has a liquid crystal cell structure (two-layer structure panel SP and two TN liquid crystal cells (back cell 1a, front cell 1b)) stacked in the normal direction of the glass substrate. Included). Cross polarizers 2a and 2b (polarizing plates whose transmission axis directions intersect) are arranged above and below the two-layer structure panel SP.

  As the alignment film of the TN liquid crystal cell 1a (1b), a horizontal alignment film SE410 manufactured by Nissan Chemical Industries, Ltd. is used. The alignment films formed on the pair of glass transparent substrates 3a1, 3a2 (3b1, 3b2) are rubbed using a rayon rubbing cloth to give a pretilt angle. The electrode sides of the pair of transparent substrates having the alignment film and the electrodes are faced to each other and bonded together with a sealing material 4a through a gap control material having a diameter of 2 μm. Then, one liquid crystal cell is manufactured by injecting a liquid crystal material having a birefringence Δn of 0.24 and a positive dielectric anisotropy added to Merck Co., Ltd. and adding a chiral material imparting twist.

  FIG. 2 shows the transmission axis of the polarizing plate and the rubbing direction of the liquid crystal cell. Although four coordinate systems are shown in the figure, they correspond to the polarizer 2a, the TN liquid crystal cell 1a, the TN liquid crystal cell 1b, and the polarizer 2b in this order from the left. In addition, a liquid crystal display element shall be observed from the back surface in the figure. The direction of twist of the liquid crystal (twist) is based on the traveling direction of the backlight. The difference between the two liquid crystal cells of the two-layer structure panel is that the twist direction of the liquid crystal is opposite. As shown in the figure, rubbing is performed so that the liquid crystal molecules of the rear liquid crystal cell 1a are twisted to 90 ° and the liquid crystal molecules of the front liquid crystal cell 1b are twisted to 90 °. Further, the alignment directions of the liquid crystal molecules (liquid crystal central molecules) located in the center with respect to the thickness direction of each of the liquid crystal cells 1a and 1b make an angle of 90 ° with each other. Further, the polarizing plates 2a and 2b are arranged with their transmission axes or absorption axes orthogonal to each other so as to be crossed Nicols. Further, the polarizing plates 2a and 2b are arranged so as to form an angle of 45 ° with the alignment direction of the liquid crystal central molecule.

  3A and 3B show examples of electrode patterns of two liquid crystal cells. Each of the liquid crystal cells 1a and 1b has a transparent electrode for applying a voltage to the liquid crystal layer for display. One cell (referred to as a display cell) has a configuration such as segment electrodes for displaying a segment, for example, electrodes a to d and e1 to e7 shown in the figure, and the other cell (referred to as a background display cell) A full-surface electrode f for displaying the entire effective display area is provided. The display cell and the background display cell can be configured regardless of which cell is on the upper side (back side).

  FIG. 4 is a conceptual diagram of a field sequential (FS) driving method according to the embodiment. For example, R (red), G (green), and B (blue) can independently emit light on the back surface of the liquid crystal display unit 101 including a two-layer panel in which two liquid crystal cells overlap each other. A cold-cathode fluorescent lamp CCFL) is provided, and a synchronous controller 20 is provided so that the driver 10a and the backlight driver 10b of the two-layer structure panel operate in synchronization.

  In the FS drive type liquid crystal display element as described above, are the two liquid crystal cells of the two-layer structure panel SP both in a drive state (a state in which a voltage sufficient to raise the liquid crystal molecules of the background display cell is applied)? In a non-driving state (state in which no voltage is applied in static driving, and in multiplex driving, a state in which the liquid crystal layer of the TN liquid crystal cell is applied with a voltage capable of maintaining optical rotation and TN alignment when no voltage is applied) It is possible to block the light of the backlight.

  FIG. 5 shows a conceptual diagram of gradation display. In the embodiment, as a simple control example, the background display cell is set to a driving state or a non-driving state, and a voltage applied to the display cell is controlled to perform gradation display of a desired tone. An example of control is given below. In the case of control without gradation display, when the background display cell 1b is turned on (or off) and the display cell is turned off (or turned on), the liquid crystal display unit is in a translucent state. The concept of the embodiment is to adjust the applied voltage to adjust the backlight light to be transmitted and display the light and shade. FIG. 5 shows an example in which the background display cell is turned ON (or turned OFF) and the display cell is turned ON by 1/2 in order to transmit 1/2 backlight light. In the embodiment, the voltage application state in the case of gradation display is represented as ◯ / ◯ ON (where ◯ / ◯ represents the proportion of the gradation display tone).

  Hereinafter, embodiments of the embodiment will be described. Here, an example in which one frame of the driving voltage is divided into three sub-frames will be described.

Example 1
FIG. 6 shows a display example. In the first embodiment, color segment display is performed on a white background, which is a typical positive display. The full surface electrode f is larger than each segment electrode and is an electrode formed on almost the entire surface of the display area. Therefore, the segment electrode in the table becomes the display area as it is. The display color of the electrode f in the table indicates the color of the background display area other than the display area defined by the segment electrode. For example, when the luminance of blue is ½ that of normal blue, the color density is expressed by adding a fraction before ½ blue and the color. In Example 1, a-cyan, b-magenta (can be displayed in shades according to temperature), c-cyan, d-magenta, e1-cyan, e2-2 / 3 cyan, e3-1 / 3 cyan, e4- Black, e5-1 / 3 magenta, e6-2 / 3 magenta, e7-magenta, f-white.

  FIG. 7 shows a table of a driving method of the liquid crystal display element according to the first embodiment. The table shown in FIG. 6 shows the ON / OFF states of the RGB LEDs in each subframe, the segment electrodes a to d and e1 to e7 provided in the display cell, and the entire surface electrode f provided in the background display cell. The ON / OFF state and the color displayed in the display area defined by each electrode. “ON” means that the LED is emitting light, and “OFF” means that it is not emitting light. ON of each electrode represents a driving state. OFF of each electrode indicates a non-driven state.

  In the first embodiment, a TN liquid crystal cell is used. When two TN liquid crystal cells whose twist directions are opposite to each other are both in the OFF state, each cell acts as a result to cancel the light twist. Become. When the two cells are both in the ON state, the liquid crystal molecules of the cells rise vertically, so that the light passes through the liquid crystal cell without being twisted, and the liquid crystal display unit including the cross polarizer is in a light-shielding state. When one of the cells is in the ON state, light passes through the cell in the ON state without being twisted, and the cell in the OFF state is twisted by 90 °. Therefore, the liquid crystal display unit is in a translucent state. In the embodiment, the twist directions are opposite to each other so as to obtain the optimum viewing angle characteristics. However, the same twist direction may be used.

  In each sub-frame, the LED emits light corresponding to the display color, and a plurality of colors can be emitted by adjusting ON / OFF and emission intensity of each of red, green and blue.

  In the sub-frame in which the backlight emits white light, all the segment electrodes and the entire surface electrode f are set to the ON state, so that the background (portion that does not overlap with the segment electrodes) is displayed in white. Each segment is assigned ON or OFF corresponding to each subframe. In the display area where the entire surface electrode f in the background display cell and each segment electrode in the display cell overlap, the liquid crystal display unit is in a light-transmitting state when either one of the cells is ON. When both cells are ON or OFF, the liquid crystal display unit is in a light shielding state.

  In addition, when it is desired to express color shading (for example, when it is desired to express the temperature of an air conditioner in shading) like the electrodes b, e2, e3, e5, e6, etc., it is effective to display gradation on the segment electrodes. Input a drive waveform to be a voltage. The drive waveform may be input by a method of operating the effective voltage, such as adjustment of the ON voltage or pulse control for time-dividing the ON waveform.

  As shown in the table of FIG. 7, the color breakless liquid crystal display element in which the liquid crystal cell and the backlight are controlled enables multicolor display exceeding the number of subframe divisions compared to the case where gradation display is not performed. In addition, display problems such as color loss, discoloration, and double image due to parallax do not occur.

(Example 2)
FIG. 8 shows a display example. The definitions of ON / OFF of the LED and ON / OFF of each electrode are the same as in the first embodiment. The second embodiment is an embodiment in which multicolor display is possible as compared with the first embodiment by the time division color mixing method. However, it should be noted that the operation is performed under conditions that may cause a color break phenomenon.

  FIG. 9 shows a table of a driving method of the liquid crystal display element according to the second embodiment. As shown in FIG. 9, in Example 2, a-blue, b-red or blue (can be displayed in shades depending on temperature), c-blue, d-red, e1-blue, e2-cyan, e3-1. / 2 cyan, e4-black, e5-1 / 2 magenta, e6-magenta, e7-red, f-white. In this way, multicolor display is possible as compared to the first embodiment.

  As described above, the liquid crystal display unit 101 is not limited to the portion where the electrodes of the two liquid crystal cells overlap each other, not only when the driving voltage of both liquid crystal cells is OFF but also when both are ON. Block the light of the light. As a result, it is possible to provide a multi-color liquid crystal display element with improved display quality by preventing display displacement and the like.

  Furthermore, a liquid crystal display element capable of displaying more colors can be provided by controlling the liquid crystal cell so that gradation display is possible.

  As another display device to which the present invention can be applied, a projection type display device can be given. 10A and 10B show an example of a projection display device.

  The projection display device shown in FIG. 10A has a structure in which a light source LS that emits parallel light, a polarizer X1, a two-layer structure panel SP, a polarizer X2, and a screen SC are arranged when the positional relationship is described in order in the light traveling direction. It is. The polarizers X1 and X2 are arranged in a crossed Nicols arrangement.

  The projection display device shown in FIG. 10B describes the positional relationship in the light traveling direction in order, for example, a light source LS that is a point light source, a polarizer X1, a two-layer structure panel SP, a polarizer X2, a Fresnel lens FL, and a screen SC. Arranged structure.

  As described above, when the display is projected onto the screen SC, the observer sees an image of light substantially perpendicular to the substrate projected onto the screen, so that it is difficult for a difference in visibility depending on the viewing angle to occur.

  Although the present invention has been described with reference to the embodiments, the present invention is not limited thereto. For example, the liquid crystal cell used in the two-layer structure panel SP is not limited to the TN liquid crystal cell, but in the vertical alignment type cell, the STN (super twist nematic) type cell, the ferroelectric liquid crystal cell, and the like, It will be obvious to those skilled in the art that the present invention can be applied if the liquid crystal cell conditions are satisfied so that the light of the backlight is shielded in both the ON state and the OFF state.

  FIG. 11 shows, as an example, the transmission axis of the polarizing plate and the rubbing direction of the liquid crystal cell when a vertically aligned liquid crystal cell in which a rubbing process is performed on a two-layer structure panel is used. The correspondence relationship between the four coordinate axes and each structure is, in order from the left, a polarizer X1, a vertical alignment liquid crystal cell VC1, a vertical alignment liquid crystal cell VC2, and a polarizer X2. As shown in the figure, when a voltage is applied to two vertically aligned liquid crystal cells, the rubbing process is performed so that the directions in which the liquid crystal molecules fall are orthogonal to each other.

  In addition, when a chiral material is added to this liquid crystal cell so that the liquid crystal molecules are twisted while being tilted when a voltage is applied, the twist direction is reversed at the same chiral pitch in the liquid crystal layer of each liquid crystal cell. Adjust to.

  Further, although an example of a segment electrode is given as an electrode formed in a display cell, a dot matrix display type liquid crystal cell in which a plurality of pixel (dot) electrodes are arranged may be used.

  Further, in the embodiment, an example is disclosed in which the background display cell is provided with the entire surface electrode f for displaying the entire effective display area, but the background display cell may be configured to include a plurality of display areas. In this case, there is a region where the liquid crystal is not driven between the plurality of regions of the background display cell, and a typical example is visually recognized as black display. It is also possible to mask print this black display portion. The mask printing may be a black mask or a desired color that matches the exterior color around the display device.

  It will be apparent to those skilled in the art that other various modifications, improvements, combinations, and the like can be made.

FIG. 1 is a cross-sectional view of a liquid crystal display portion which is a main part of a liquid crystal display element according to an embodiment. FIG. 2 is a plan view showing the transmission axis of the polarizing plate and the rubbing direction of the liquid crystal cell. 3A and 3B are examples of electrode patterns of two liquid crystal cells. FIG. 4 is a conceptual diagram of a field sequential (FS) driving method according to the embodiment. FIG. 5 is a conceptual diagram of gradation display. FIG. 6 is a display example according to the first embodiment. FIG. 7 is a table of liquid crystal display element driving methods according to the first embodiment. FIG. 8 is a display example according to the second embodiment. FIG. 9 is a table of a driving method of the liquid crystal display element according to the second embodiment. 10A and 10B are examples of a projection display device to which the embodiment is applied. FIG. 11 is a plan view showing the transmission axis of the polarizing plate and the rubbing direction of the liquid crystal cell when a vertically aligned liquid crystal cell is used for the two-layer structure panel.

Explanation of symbols

1a, 1b, VC1, VC2 Liquid crystal cells 2a, 2b, X1, X2 Polarizer
3a1, 3a2, 3b1, 3b2 Substrate 4a, 4b Sealing material 5a1, 5a2, 5b1, 5b2, a, b, c, d, e1 to e7, f Electrode 10a, 10b Driver 20 Synchronous controller 101 Liquid crystal display part FL Fresnel lens LS Light source SC Screen SP Two-layer structure panel

Claims (11)

And at least a pair of the first pair of substrates, each including a first pair of substrates and a first liquid crystal layer held between the first pair of substrates, wherein the first pair of substrates displays a predetermined character or figure. A first liquid crystal cell comprising: a first pixel electrode, wherein the alignment state of the first liquid crystal layer can be controlled by adjusting a voltage applied to the first pixel electrode;
A second pair of substrates facing each other and a second liquid crystal layer held between the second pair of substrates, wherein the second pair of substrates is a predetermined character in the first liquid crystal cell. A second liquid crystal cell including a second pixel electrode that completely includes a figure and a figure, and capable of controlling an alignment state of the second liquid crystal layer by adjusting a voltage applied to the second pixel electrode;
Two cross-polarizers disposed on both sides with respect to the normal direction of the substrate in the layer structure panel including the first and second liquid crystal cells;
A light source capable of emitting multiple colors;
A plurality of pixel regions of the structure including the first and second liquid crystal cells in which one frame is time-divided into a plurality of subframes, light of a predetermined color is emitted in each subframe, and the light emission is synchronized with the light emission And a control circuit for controlling the state of light transmission and light shielding,
The twist angles of the liquid crystal molecules in the liquid crystal layer in the first liquid crystal cell and the second liquid crystal cell are equal, the orientation direction of the liquid crystal layer central molecule in the first liquid crystal cell, and the liquid crystal layer in the second liquid crystal cell The orientation directions of the central molecules are orthogonal to each other, and the retardation (Δnd) of the liquid crystal layer in the first liquid crystal cell and the second liquid crystal cell is equal,
The first liquid crystal cell and the first liquid crystal cell each defining a predetermined display area defined by an electrode formed in the first liquid crystal cell and a second pixel electrode formed in the second liquid crystal cell. When both liquid crystal cells 2 are in a driving state or a non-driving state, each of the display areas is in a light shielding state,
A liquid crystal display element that performs gradation display by controlling an alignment state of a liquid crystal layer of at least one liquid crystal cell of the first and second liquid crystal cells to a driving state between a driving state and a non-driving state. 2. The liquid crystal display element according to claim 1, wherein the control circuit controls the predetermined display region to be in a light-transmitting state only in any one of the sub-frames or to be in a light-shielding state in all the sub-frames. .   2. The liquid crystal display element according to claim 1, wherein the control circuit performs mixed color display by transmitting one primary color light in each of the sub-frames, and in a certain display area by setting the light-transmitting state in a plurality of sub-frames.   The liquid crystal display element according to claim 1, wherein the light source includes an LED. It is a projection type display apparatus containing the liquid crystal display element of any one of Claims 1-4 ,
A projection display device in which the light source emits parallel light. It is a projection type display apparatus containing the liquid crystal display element of any one of Claims 1-4 ,
The light source is a point light source that emits radiation;
Furthermore, a projection type display device having a Fresnel lens on the opposite side of the point light source with the liquid crystal display element interposed therebetween. And at least a pair of the first pair of substrates, each including a first pair of substrates and a first liquid crystal layer held between the first pair of substrates, wherein the first pair of substrates displays a predetermined character or figure. A first liquid crystal cell comprising: a first pixel electrode, wherein the alignment state of the first liquid crystal layer can be controlled by adjusting a voltage applied to the first pixel electrode;
A second pair of substrates facing each other and a second liquid crystal layer held between the second pair of substrates, wherein the second pair of substrates is a predetermined character in the first liquid crystal cell. A second liquid crystal cell including a second pixel electrode that completely includes a figure and a figure, and capable of controlling an alignment state of the second liquid crystal layer by adjusting a voltage applied to the second pixel electrode;
Two cross-polarizers disposed on both sides with respect to the normal direction of the substrate in the layer structure panel including the first and second liquid crystal cells;
A light source capable of emitting multiple colors;
A plurality of pixel regions of the structure including the first and second liquid crystal cells in which one frame is time-divided into a plurality of subframes, light of a predetermined color is emitted in each subframe, and the light emission is synchronized with the light emission Toru light and have a control circuit for controlling the state of light shielding of
The twist angles of the liquid crystal molecules in the liquid crystal layer in the first liquid crystal cell and the second liquid crystal cell are equal, the orientation direction of the liquid crystal layer central molecule in the first liquid crystal cell, and the liquid crystal layer in the second liquid crystal cell A method for driving a liquid crystal display element in which the orientation directions of the central molecules are orthogonal to each other and the retardation (Δnd) of the liquid crystal layer in the first liquid crystal cell and the second liquid crystal cell is equal ,
A liquid crystal display element driving method for performing gradation display by controlling an alignment state of a liquid crystal layer of at least one of the first and second liquid crystal cells to a driving state intermediate between a driving state and a non-driving state . A display area that is in a translucent state in one subframe is controlled to be in a light-shielding state in another subframe,
One frame includes at least a first subframe and a second subframe;
The light source is capable of emitting at least a first color and a second color;
The liquid crystal display element drive according to claim 7 , wherein the second color is transmitted in the second subframe to a display area different from the display area in which the first color is transmitted in the first subframe. Method. 8. The method of driving a liquid crystal display element according to claim 7, wherein mixed color display is performed by transmitting light of one primary color in each of the sub-frames and in a certain display area by transmitting light in a plurality of sub-frames. The method for driving a projection display device using a liquid crystal display element according to any one of claims 7 to 9 , wherein the light source has a structure for emitting parallel light. A method for driving a projection display device using the liquid crystal display element according to any one of claims 7 to 9 ,
A driving method of a projection display device, wherein the light source is a point light source that emits radiated light, and has a Fresnel lens on the opposite side of the point light source across the liquid crystal display element.

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