KR100851375B1 - Liquid crystal display and driving method thereof - Google Patents

Abstract

An object of the present invention is to provide a liquid crystal display device capable of displaying various colors.

[Measures] Between a first substrate having a first electrode, a second substrate having a second electrode and defining a first and a second display unit and a background region, and an electric first substrate and a second substrate. Transmitting or reflecting incident light according to the liquid crystal layer disposed, the first polarizing plate disposed opposite to the first electrical substrate, the first light source facing the first polarizing plate, and the polarization state disposed opposite the second substrate. And a first and a second exit port arranged opposite to the second polarizing plate and displaying the first and second display units, the second polarizing plate being disposed opposite to the electrically transmitting and reflecting plate. A voltage applying means capable of applying a voltage between the second light source, the electric first electrode and the second electrode, time-dividing one frame into sub-frames, and emitting an electric first or second light source within each sub-frame. Has a control circuit, the electrical transmission and reflection plate is the electrical first polarizing plate, and the voltage A liquid crystal display device is provided which reflects light in a polarization state that passes through an unapplied liquid crystal layer and transmits light in a polarization state that passes through an electric second polarizing plate.

Liquid crystal display device, compensation cell, driving cell, liquid crystal cell for display, liquid crystal cell for dividing area

Description

Liquid crystal display device and liquid crystal display device driving method {LIQUID CRYSTAL DISPLAY AND DRIVING METHOD THEREOF}

1A to 1C are views for briefly explaining a liquid crystal display device according to Japanese Patent Application No. 2004-118870.

2A to 2C are diagrams for explaining the outline of the liquid crystal display device according to the embodiment described above with reference to FIGS. 3 to 7.

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

4 is a schematic exploded perspective view showing a liquid crystal display device according to a second embodiment.

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

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

7 is a schematic exploded perspective view showing a liquid crystal display device according to a fifth embodiment.

8A and 8B are views for explaining a method of driving the liquid crystal display device according to the embodiment.

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

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

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.

Fig. 12 is a timing chart showing an example of display control in the liquid crystal display element using the FS driving method.

13 is a timing chart for explaining the liquid crystal driving method according to the above proposal.

[Explanation of symbols on the main parts of the drawings]

30 Display section 31 to 37 Display unit

38 Background area 50a Upper board

50b Lower substrate 51a Upper glass substrate

51b Lower Glass Substrate

52a Upper transparent electrode 52b Lower transparent electrode

53a upper alignment layer 53b lower alignment layer

54a upper polarizer 54b lower polarizer

54c upper color polarizer 54d lower color polarizer

54e upper linear polarizer 54f center linear polarizer

54g top 1/4 wave plate 54h center 1/4 wave plate

54i central polarizer

55 Liquid Crystal Layer 56 Multi-Color Backlight

57 white backlight 58 phase difference plate

59 black mask 60 area color filter

60r red 60g green

60b blue 60w white

66 Multi-Color Front Light 67 Polarization Separation and Reflector

68 Voltage application means 69 D-BEF

70 Compensation Cell 71 Driving Cell

72 Phase difference plate 73 Broadband cholesteric film

75 Backlight Synchronous Drive Circuit 76 Display Liquid Crystal Cell

77 Liquid Crystal Cell for Eria Division 78 Synchronization Circuit

81 ~ 87 Synchronization Circuit 88a ~ 88u Dot

89 segment 90 background area

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

In a liquid crystal display device having a segment type, a dot matrix type, and a combination of both, display colors of regions other than the segment portion or dot portion (non-display region) used for display are adjusted. In order to improve the visibility and design of the display, it is performed.

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

See Figure 9A. The liquid crystal display element is configured to include an upper substrate 50a and a lower substrate 50b that are disposed substantially parallel to each other and a liquid crystal layer 55 sandwiched therebetween. The upper substrate 50a and the lower substrate 50b are formed of, for example, glass substrates (upper and lower glass substrates 51a, 51b) that are flat plates, and transparent conductive materials such as indium tin oxide (ITO) on opposite surfaces thereof. Electrodes having a predetermined pattern (upper and lower transparent electrodes 52a and 52b) and alignment films formed to cover each electrode (upper and lower alignment films 53a and 53b). Is a twisted nematic liquid crystal layer formed of, for example, a nematic liquid crystal having positive dielectric anisotropy (Δε> 0), and is caused by rubbing directions of the upper and lower alignment layers 53a and 53b. The predetermined twist angle is 90 degrees, for example.

A pair of upper and lower polarizing plates 54a and 54b are disposed outside the upper substrate 50a and the lower substrate 50b in orthogonal Nicols 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. In the state where no voltage is applied, the polarization direction of the incident light rotates in accordance with the orientation of the liquid crystal molecules, passes through the polarizing plate, and normally displays white. In Fig. 9A, the direction of the transmission axis is indicated by an arrow.

A multi color back light 56 is disposed outside the lower polarizer 54b. The multi-colored backlight 56 is a backlight capable of emitting light of a plurality of colors. For example, an RGB multicolor LED light source is used.

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

Light is emitted from the multi-color backlight 56 and shielded by the color of the light emitted when the light passing through the liquid crystal layer 55 passes through the upper polarizing plate 54a to the upper polarizing plate 54a. "Dark" display is performed.

In a normally white type liquid crystal display device in which the display part is blackly displayed using the "dark" display, a color tone of a non-display area is used by using a multi-color backlight that can change the emission color of the backlight. It is possible to change it arbitrarily.

See Figure 9B. The liquid crystal display shown in Fig. 9B uses the upper and lower color polarizers 54c and 54d in place of the upper and lower polarizers 54a and 54b when compared to that shown in Fig. 9A, and It differs in that the white backlight 57 is used instead of the multi-colored backlight 56.

The white backlight 57 is configured using, for example, a cold cathode fluorescent lamp (CCFL). In some cases, an inorganic white LED or an organic white LED may be used.

And the upper and lower color polarizing plates 54c and 54d are orthogonal nicole arranged.

The upper and lower polarizers 54a and 54b of FIG. 9A are, for example, polarizing plates of new neutral gray tones, while the upper and lower color polarizers 54c and 54d of FIG. 9B are, for example, pigmented. It is a color polarizing plate dyed by. 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 a color determined by the upper and lower color polarizing plates 54c and 54d.

See Figure 9C. The liquid crystal display shown in Fig. 9C differs in that the phase difference plate 58 is inserted between the upper polarizing plate 54a and the upper substrate 50a when compared with that shown in Fig. 9B. By inserting the retardation plate 58, it is possible to adjust the color tone of the non-display area.

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

In the liquid crystal display elements shown in Figs. 9B and 9C, the color of the non-display area cannot be changed after completion of the elements.

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

See FIG. 10A. Compared to that shown in FIG. 9A, the liquid crystal display shown in FIG. 10A has an area color filter 60 and a black mask 59 between the upper and lower substrates 50a and 50b. ) Is disposed and the white backlight 57 is used instead of the multi-color backlight 56.

The eria color filter 60 is comprised including the red part 60r, the green part 60g, the blue part 60b, and the white part 60w, for example. In the illustrated liquid crystal display device, light emitted from the white backlight 57 passes through different color regions (each color portion 60r, 60g, 60b, 60w) of the eria color filter 60. The display becomes possible.

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

See FIG. 10B. The liquid crystal display shown in Fig. 10B differs in that the upper and lower polarizing plates 54a and 54b are arranged in parallel Nicols, as compared with that shown in Fig. 9A. When the light emitted from the multi-color backlight 56 is polarized by the lower polarizing plate 54b, and rotates the polarization direction according to the alignment state of the liquid crystal molecules when no voltage is applied, the light is orthogonal to the polarization direction of the upper polarizing plate 54a. do. That is, the liquid crystal display device shown in this drawing is a normal black type liquid crystal display device using a multi-color backlight. The display using a plurality of colors can be performed by the color of light emitted when voltage is applied.

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

See Fig. 11A. The liquid crystal display element shown in Fig. 11A includes a backlight synchronous driving circuit 75 as shown in Fig. 10B.

In the FS driving, the multi-color backlight 56 repeats time-division light emission in order of red (R), green (G), and blue (B), for example. The backlight synchronous driving circuit 75 is connected between the multi-colored backlight 56 and the upper and lower transparent electrodes 52a and 52b, for example, and the liquid crystal cell is synchronized with the light emission timing of the multi-colored backlight 56. (cell) (switching (on-off which transmits and does not transmit light)) is performed.

In the FS driving method, image data is decomposed into color data of R, G, and B, and the display is performed by combining (additional mixed color) on the time axis. By converting the light emission of the multi-colored backlight 56 at a high speed so that the human eye cannot disassemble it, the human eye recognizes the mixed color image.

See Fig. 11B. The display of the liquid crystal display element is performed by the display unit 30 of seven segments, for example. The display unit 30 includes display units (each segment) 31 to 37 and a background area 38. In each of the display units 31 to 37, electrodes that can be driven independently are correspondingly provided, and the electrodes are selectively provided. By applying a voltage, the alignment state of the liquid crystal molecules of the liquid crystal layer corresponding to the electrode is changed, and for example, respective numbers of "0" to "9" can be displayed.

In the present specification, for example, a display unit used for displaying each number is called a display area, and other display units and background areas are called non-display areas. For example, when the numeral "7" is displayed, the display area means the display units 31 to 33, and the non-display area means the 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. Referring to Fig. 12, the liquid crystal drive method of the FS system will be described.

In the FS driving method, as described above, the multicolor backlight 56 repeats time-division light emission in the order of R, G, and B, for example. The period during which each of R, G, and B emit light sequentially is called one frame. One frame is 16.7 ms, for example. One image is displayed in units of frames. In order to temporarily mix light of R and G. B, it is preferable that one frame is 20 ms or less (frame frequency is 50 Hz or more), for example.

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

See the section on "Multicolor Backlight." One SB is divided into a light emission period and a blank period. Emission of any one of R, G, and B is performed in the light emission period of each SB (SB1 to SB3). 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 device, 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 during which no color light is emitted, and is a time required for the liquid crystal molecules of the liquid crystal layer to change the alignment state to some extent by the applied voltage.

Refer to the section of Display Unit 31. The notation "display unit 31", "display unit 32", or the like used below indicates each display unit shown in Fig. 11B. In addition, in this drawing, "ON" at the stage of the display unit of the driving timing chart means that the liquid crystal display element is in a state of transmitting light, and "OFF" means that the liquid crystal display element emits light. It means that the state does not penetrate.

In the display unit 31, light is transmitted through SB1 and SB2. Thus, sulfur (Y), a mixture of R and G, is visually recognized by the observer.

Refer to the section of "Display Unit 32". In the display unit 32, light is transmitted through SB1 and SB3. Therefore, the magenta (M), which is a mixture of R and B, is recognized by the observer.

Refer to the section in Display Unit 37. The display unit 37 transmits light in SB2. Thus G is perceived by the observer.

However, when the line of sight deviates from the display portion obtained by additive color mixing of two or more colors, or a vibration is applied to the liquid crystal display element, a phenomenon in which the images of the respective SBs that are not recognized by the observer's eyes are separated and observed, The so-called color break phenomenon may occur. The color brake phenomenon occurs remarkably when the surroundings are dark. The occurrence of the color brake phenomenon is also undesirable in the influence on the observer's mind.

Therefore, the present inventors proposed a method of driving a liquid crystal display device which prevents color breaks by forming and emitting light having a desired color for each SB, so that the display unit which is in a transmissive state in one SB is in a light shielding state in another SB. . (See Patent Document 1, for example)

13 is a timing chart for explaining a liquid crystal driving method according to the above proposal.

See the section on "Multicolor Backlight." In one frame shown, white light is emitted by simultaneous lighting of a plurality of light sources in SB1, orange in SB2, and blue light by single light emission in SB3. In this figure, the blank period is 3ms during the 1SB period of 5.57ms.

Refer to the section of Display Unit 31. In the display unit 31, only SB1 is in a light transmitting state. Therefore, the display in white is performed.

Refer to the column of Display Unit 32. In the display unit 32, all the SBs are shielded. Therefore, the display color becomes black black.

Refer to the section in Display Unit 37. In the display unit 37, only SB2 is in a light transmitting state. Therefore, the display in orange color is performed.

 According to the driving method of the liquid crystal display element of patent document 1, since the lighting color of a multicolor backlight can be changed for every frame, various color display is possible.

However, in the above-described technique, it is difficult to control the display region and the non-display region separately from each other and in any color tone after the manufacture of the liquid crystal display element. In the case of a full dot matrix liquid crystal display device using a microcolor filter, it is possible to make the actual non-display area and the color tone of the display area to be performed independently, but the cost of using the microcolor filter is high. do.

In particular, in the case of a segment type or a composite type of a segment and a dot, a low cost is required, and therefore, it is preferable not to use a color filter such as a micro color filter (see Patent Document 2, for example).

In FS driving, the optical response of the liquid crystal layer is preferably completed in one SB. When FS drive is performed using a liquid crystal display device having a liquid crystal layer having a slow optical response, it is sometimes difficult to obtain an intended display color. In particular, for example, the duty ratio is large. In the case of a simple matrix drive in a dot matrix display element, since a liquid crystal operation mode (for example, S-number mode, etc.) with a slow response speed is usually used, it is considered that the intended display state is often difficult to realize. .

Patent Document 1: Japanese Patent Application Laid-Open No. 2005-070440

Patent Document 2: Japanese Patent Application Laid-Open No. 49-074438

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

According to an aspect of the present invention, there is provided a first substrate having a first electrode having a predetermined shape, and a second substrate having a second electrode having a predetermined shape, which is disposed substantially parallel to the first substrate. A plurality of display units including first and second display units for displaying at positions where the electrodes and the second electrodes face each other are defined, and a background region is defined at positions where the first and second electrodes do not face each other. A liquid crystal layer disposed between the second substrate, the first electrical substrate, and the second substrate, the liquid crystal layer being capable of switching the alignment state by applying a voltage between the electrical first electrode and the second electrode; A first polarizing plate disposed on a side opposite to the side on which the liquid crystal side of the substrate is disposed, a first light source disposed on a side opposite to the side on which the first substrate of the first polarizing plate is disposed, and a liquid crystal layer of the second substrate Transmission which transmits or reflects incident light according to the polarization state arranged on the side opposite to the side The reflecting plate, the second polarizing plate arranged on the side opposite to the side on which the electric second substrate of the electric transmissive plate is arranged, and the side opposite to the side on which the electric transmitting and reflecting plate of the electric second polarizing plate is arranged, are each emitted by the emitted light. A second light source having first and second outlets capable of displaying the first and second display units, and voltage applying means for applying a voltage between the first and second electrodes; And a control circuit capable of time-dividing one frame into a plurality of subframes and emitting an electric first or second light source within each subframe when the period for displaying one image is one frame. Reflects the light of the polarization state transmitted through the electric first polarizing plate and the electric liquid crystal layer when no voltage is applied, and transmits the light of the polarization state passing through the electric second polarizing plate, the electric second polarizing plate, the electric transmission and reflecting plate, And voltage unattended Light passing through the liquid crystal layer at the time of electricity is provided to the liquid crystal display element in the normal black type with respect to light emitted from electrical second light source, which light shield electrically the first polarizing plate.

According to another aspect of the present invention, there is provided a first substrate having a first electrode having a predetermined shape, and a second substrate having a second electrode having a predetermined shape, disposed substantially parallel to the electrical first substrate. A plurality of display units including first and second display units for displaying at a position where the first electrode and the second electrode face each other are defined, and 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 capable of switching an alignment state by applying a voltage between the first and second electrodes, the second substrate being disposed between the first and second substrates; The first polarizing plate disposed on the side opposite to the side on which the liquid crystal side of the first substrate is disposed, the first light source disposed on the side opposite to the side on which the first substrate of the electric first polarizing plate is disposed, and the liquid crystal layer of the electric second substrate The incident light is transmitted in accordance with the polarization state disposed on the opposite side to the opposite side, or It is arrange | positioned on the opposite side to the side which the reflecting and reflecting plate, the 2nd polarizing plate arrange | positioned on the opposite side to the side where the electric 2nd board of the electrotransmitting and reflecting plate is arrange | positioned, and the electrotransmission and reflecting plate of the electric 2nd polarizing plate are arrange | positioned, and radiate | emitted A second light source having first and second exit ports capable of displaying electric first and second display units with one light, respectively, and a voltage for applying a voltage between the first and second electrodes An application means and a control circuit capable of time-dividing one frame into a plurality of subframes and emitting an electric first or second light source within each subframe when the period for displaying one image is one frame; The transmissive and reflective plate reflects light in a polarization state passing through the first polarizing plate and the electric liquid crystal layer when no voltage is applied, and transmits light in a polarization state passing through the second polarizing plate. Reflective plate, The light transmitted through the electric liquid crystal layer when no voltage is applied is a driving method of a normal black type liquid crystal display device with respect to light emitted from the electric second light source, which is shielded by the electric first polarizing plate. A process of displaying with light emitted from the first light source and a process of displaying with light emitted from the second light source in another subframe, wherein each of the electrical display units is at most one subframe in one frame A method of driving a liquid crystal display device in which display is performed by light emitted from an electric first or second light source is provided.

According to the present invention, a liquid crystal display device capable of displaying various colors and a driving method thereof can be provided.

The present inventor has proposed a liquid crystal display device having a novel structure which enables various color display in Japanese Patent Application No. 2006-005156. This invention deepens further consideration about the invention which concerns on the said application.

The inventors of the present invention also propose a novel liquid crystal display device and a display method thereof in Japanese Patent Application No. 2004-118870.

A liquid crystal display device according to Japanese Patent Application No. 2004-118870 will be briefly described with reference to FIGS. 1A to 1C.

1A shows a display portion of a liquid crystal display element. The display portion includes, for example, a segment portion (STANLEY R & D) and a dot portion (in this figure, a portion indicated by a square in a matrix form). According to the liquid crystal display device, for example, when the character display is performed for each phrase of "STANLEY", "R & D" or in the dot portion, it is possible to change the color tone in units of characters.

For example, the segment part of "STANLEY" and "R & D" is displayed. In the dot portion, one character is displayed at 20 dots in five rows and four columns in order from the left, and the characters "L", "C", and "D" are displayed in the whole dot portion. As for the display color, for example, "STANLEY" and "L" are red, "C" is blue, "R & D" and "D" are yellow. A diagonal line is shown in the figure.

Fig. 1B is a schematic exploded perspective view showing an internal configuration example of a liquid crystal display device. The liquid crystal display shown in this drawing comprises a liquid crystal cell 76 for display and a liquid crystal cell 77 for dividing an area.

Both cells 76 and 77 are arranged with the liquid crystal cell 76 for display on the upper side and the liquid crystal cell 77 for the area dividing on the lower side.

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

With respect to both of the cells 76 and 77, the upper substrate 50a and the lower substrate 50b are, for example, flat plate glass substrates (upper and lower glass substrates 51a and 51b), and on their opposite surfaces, ITO. An electrode (upper and lower transparent electrodes 52a and 52b) formed of a transparent conductive material, such as a transparent conductive material, and having a predetermined pattern, and an alignment film (upper and lower alignment films 53a and 53b) formed to cover each electrode.

The liquid crystal layer 55 is, for example, a twisted nematic liquid crystal layer formed of a nematic liquid crystal having positive dielectric anisotropy (Δε> 0), and the rubbing directions of the upper and lower alignment layers 53a and 53b. Twist angle determined according to, for example, is 90 °.

The voltage application means 68 is connected between the upper transparent electrodes 52a and the lower transparent electrodes 52b so as to apply an arbitrary voltage between both the electrodes 52a and 52b. By the voltage applied between the positive electrodes 52a and 52b by the voltage applying means 68, the alignment state of the liquid crystal molecules of the liquid crystal layer 55 between the positive electrodes 52a and 52b can be changed.

The liquid crystal cell 76 for display and the liquid crystal cell 77 for dividing an area differ in the shape of an electrode. The electrode of the liquid crystal cell 76 for display has a shape corresponding to the shape of the dot portion and the segment portion shown in Fig. 1A. An electrode of the area dividing liquid crystal cell 77 will be described with reference to the following drawings.

The upper polarizing plate 54a is disposed outside the upper substrate 50a of the liquid crystal cell 76 for display. The lower polarizing plate 54b is disposed outside the lower substrate 50b of the liquid crystal cell 77 for dividing the eria. Also, a central polarizer 54i is disposed between both 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 shown by an arrow.

The portion composed of the liquid crystal cell 76 for display, the upper polarizing plate 54a, and the central polarizing plate 54i, and the portion consisting of the liquid crystal cell 77 for the dividing region, the lower polarizing plate 54b, and the central polarizing plate 54i For example, all are normal black liquid crystal elements.

The multicolor backlight 56 is disposed outside the lower polarizing plate 54b. The multicolor backlight 56 is a light capable of selectively emitting a plurality of colors of light, and has, for example, an RGB multicolor LED light source laterally and irradiates the incident light toward the liquid crystal layer. As the color light source, it is possible to configure using an organic LED, an inorganic LED, a CCFL, an FE lamp, or the like. The change in the emitted light color may be realized by the configuration using a plurality of monochromatic light sources of different emission colors or by the configuration using a single light source capable of changing the emission color.

 The synchronization circuit 78 is connected between the multicolor backlight 56 and the voltage application means 68 of the liquid crystal cell 77 for dividing the area. The synchronizing circuit 78 applies the dots of the multi-color backlight 56, the extinction, and the voltage applied to both electrodes 52a and 52b of the liquid crystal cell 77 for dividing the region (the alignment state of the liquid crystal molecules of the liquid crystal layer 55). Can be motivated.

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

From the multicolor backlight 56, light of red, blue, and yellow is emitted 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 54b and enters into the liquid crystal cell 77 for dividing an area.

The area of the liquid crystal cell 77 for dividing the area is divided into predetermined areas of the light from the multi-color backlight 56 that is incident on the upper substrate 50a side according to the shape of the electrode (5 in the areas 81 to 85 in FIG. 1C). It is possible to partition and exit each area. That is, the shape of the electrode of the eria division liquid crystal cell 77 is formed corresponding to the shape of eria 81-85.

The area 81 is an area corresponding to an area of 5 rows and 4 columns located on the left side of the dot portions shown in Fig. 1A. With the light exiting the area 81, the letter "L" can be displayed.

The area 82 is an area corresponding to an area of 5 rows and 4 columns located at the center among the dot portions shown in Fig. 1A. With the light exiting the area 82, the letter "C" can be displayed.

The area 83 is an area corresponding to an area of 5 rows and 4 columns located on the right side of the dot portions shown in Fig. 1A. With the light exiting the area 83, the letter "D" can be displayed.

The area 84 is an area corresponding to the character string "STANLEY" among the segment parts shown in FIG. 1A, and the corresponding letter can be displayed by the light emitted from the area 84. FIG.

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

In the liquid crystal cell 76 for display through SB1 to SB3, of the segment portions displaying "STANLEY" and "R & D", among the electrodes 52a and 52b corresponding to the five rows and four columns of the left, the center, and the right of the dot portion, Voltages are applied between the electrodes 52a and 52b that display the letters "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 liquid crystal cell 77 for dividing the area. For this reason, of the red light which emitted the multicolor backlight 56, only the light which emits the areas 81 and 84 permeate | transmits the center polarizing plate 54i, maintaining the polarization state defined by the lower polarizing plate 54b.

In the light transmitted through the central polarizing plate 54i, in the display liquid crystal cell 76, the segment portion displaying "STANLEY" and the electrodes 52a and 52b corresponding to the five rows and four columns on the left side of the dot portion, Only the light transmitted through the liquid crystal layer 55 corresponding to the electrodes 52a and 52b for displaying the letter L (the red light for displaying the letters "STANLEY" and "L") is intact and polarized to the upper polarizing plate. It passes through 54a and reaches the observer's eye.

In SB2, blue light is emitted from the multicolor backlight 56 as described above. Further, a voltage is applied between the electrodes 52a and 52b corresponding to the areas 83 and 85 of the liquid crystal cell 77 for division of the area. In the display liquid crystal cell 76, the electrodes 52a and 52b which display the character of "D" among the segment parts which display "R & D" and the electrodes 52a and 52b corresponding to 5 rows and 4 columns on the right side of a dot part. Since a voltage is applied between them, only the blue light that represents the letters " R & D " and " D " passes through the upper polarizing plate 54a and reaches the observer's eye.

In SB3, yellow light is emitted from the multicolor backlight 56 as described above. Furthermore, a voltage is applied between the electrodes 52a and 52b corresponding to the area 82 of the liquid crystal cell 77 for area dividing. In the liquid crystal cell 76 for display, a voltage is applied between the electrodes 52a and 52b for displaying the letter "C" among the electrodes 52a and 52b corresponding to five rows and four columns in the center of the dot portion. Only yellow light displaying the letter "C" penetrates the upper polarizing plate 54a and reaches the observer's eye.

Thus, when the liquid crystal display device according to Japanese Patent Application No. 2004-118870 is used, the color tone can be changed in units of characters, for example, when text is displayed at each segment and in the dot portion.

2A to 2C, the outline of the liquid crystal display device according to the embodiment described with reference to Figs. 3 to 7 will be described.

See Figure 2A. The liquid crystal display device includes a liquid crystal cell 76 for display and a liquid crystal cell 77 for dividing an area. In both cells 76 and 77, the liquid crystal cell 76 for display is positioned on the upper side, and the liquid crystal cell 77 for dividing the area is disposed on the lower side.

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

The upper substrate 50a and the lower substrate 50b are formed of a transparent conductive material such as ITO on, for example, a glass substrate (upper and lower glass substrates 51a, 51b) of a flat plate and opposite surfaces thereof to form a predetermined pattern. Electrodes (upper and lower transparent electrodes 52a and 52b) and alignment films (upper and lower alignment films 53a and 53b) formed covering each electrode.

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 positive electrodes 52a and 52b. By the voltage applied between the positive electrodes 52a and 52b by the voltage applying terminal 68, the alignment state of the liquid crystal molecules of the liquid crystal layer 55 between the positive electrodes 52a and 52b can be changed.

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

The upper polarizing plate 52a is disposed outside the upper substrate 50a of the liquid crystal cell 76 for display. The lower polarizing plate 54b is disposed on the outer side of the lower substrate 50b of the liquid crystal cell 77 for area dividing. Further, a polarization separating and reflecting plate 67 is disposed outside the lower substrate 50b of the liquid crystal cell 76 for display. The center polarizing plate 54i is disposed between the polarization splitting and reflecting plate 67 and the upper substrate 50a of the liquid crystal cell 77 for dividing the region.

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 upper, lower and center 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 circular polarizing plate and an elliptical polarizing plate, a retardation plate is further provided inside.

The polarization splitting and reflecting plate 67 transmits or reflects incident light in accordance with its polarization state. As the polarization separating and reflecting plate 67, for example, a broadband collet used for D-BEF (brightness enhane film) manufactured by 3M Co., Ltd., and brightness enhancement film PCF (polarization conversion film) manufactured by Ildong Electric Co., Ltd. Steric film can be used.

Also in the liquid crystal cell 76 for display and in the liquid crystal cell 77 for dividing an area, an arbitrary voltage is applied between the upper electrodes 52a and 52b between the upper transparent electrode 52a and the lower transparent electrode 52b. The voltage application means 68 that can be applied is connected. By the voltage applied between the positive electrodes 52a and 52b by the voltage applying means 68, the alignment state of the liquid crystal molecules of the liquid crystal layer 55 between the positive electrodes 52a and 52b can be changed.

The multicolored front light 66 and the multicolored back light 56 are disposed outside the upper polarizing plate 54a and the lower polarizing plate 54b, respectively. The multicolored front light 66 and the multicolored back light 56 are lights capable of selectively emitting light of a plurality of colors. For example, the multicolored front light 66 has an RGB multicolor LED light source laterally, and the incident light has a liquid crystal layer. Investigate towards As the color light source, it is possible to configure using an organic LED, an inorganic LED, a CCFL, an FE lamp, or the like. The change in the emitted light color may be realized by the configuration using a plurality of monochromatic light sources of different emission colors or by the configuration using a single light source capable of changing the emission color.

The multicolor front light 66 transmits light from the liquid crystal layer.

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

The synchronizing circuit 78 includes the points of the multicolor backlight 56, the lights off, the points of the multicolor front lights 66, the lights off, and the switching of the liquid crystal layers 55 of both cells 76 and 77 (orientation of the liquid crystal molecules). Is a circuit for synchronizing the change of the state and the switching between the light-emitting state and the light-shielding state. Time-division of one frame into a plurality of subframes, and the multicolored front light 66 or the multicolored back light 56 are emitted within each subframe, and the liquid crystal layers of both cells 76 and 77 are synchronized with the light emission. (55) can be switched.

The portion composed of the liquid crystal cell 76 for display, the upper and center polarizing plates 54a and 54i, and the polarization separating and reflecting plate 67 has a normal black type with respect to light emitted from the multicolor backlight 56. It is a liquid crystal element. In addition, the part comprised of the area | region and the lower polarizing plate 54i, 54b for an area | region division of an area | region is a liquid crystal element of a normal black type or a normal white type with respect to the light emitted from the far color backlight 56. As shown in FIG. .

2B is a plan view illustrating a display unit of a liquid crystal display device. By the upper transparent electrode 52a and the lower transparent electrode 52b of the liquid crystal cell 76 for display, a display portion (single or plural display units for displaying and a background area) can be defined on the upper substrate 50a side. have.

The display unit includes dots 88a to 88u, segments 89, and a background region 90, which are display units. In each of the dots 88a-88u and the segment 89, the electrode which can drive independently is respectively provided in the liquid crystal cell 76 for display. By selectively applying a voltage to these electrodes, various display can be performed by changing the orientation state of the liquid crystal molecules of the liquid crystal layer 55 corresponding to the electrodes.

The display unit is defined corresponding to the position where the upper transparent electrode 52a and the lower transparent electrode 52b of the liquid crystal cell 76 for display face each other, and the background area is the upper transparent electrode 52a of the liquid crystal cell 76 for display. ) And the lower transparent electrode 52b are defined corresponding to positions not facing each other.

FIG. 2C is a plan view showing an area defined on the upper substrate 50a side of the area dividing liquid crystal cell 77.

The area partitioned liquid crystal cell 77 emits light from the incident multicolor backlight 56 for each predetermined area defined by the shape of the electrode (two areas of areas 86 and 87 in the area shown in FIG. 2C). It is possible to do The shapes of the regions 86 and 87 correspond to the shapes of the electrodes of the liquid crystal cell 77 for dividing the eria, and the positions of the upper transparent electrode 52a and the lower transparent electrode 52b of the liquid crystal cell 77 for dividing the eria face each other. It is defined.

In such a liquid crystal display device, by controlling the light emission colors of the multicolor front light 66 and the multi color back light 56, the display area and the non-display area can be independently expressed in different color tones.

Hereinafter, the specific structure and operation | movement of a liquid crystal display element are demonstrated. In the liquid crystal display device shown in Figs. 3 to 5, D-BEF manufactured by 3M Corporation was used as the polarization separation and reflection plate 67 of Fig. 2A. The D-BEF has a reflection axis in the in-plane direction and reflects light polarized in the reflection axis direction. In addition, in the liquid crystal display device shown in Figs. 6 and 7, a cholesteric film used for the brightness enhancement film PCF of Ildong Electric Co., Ltd. as the polarization separation and reflection plate 67 of Fig. 2A. ) Was used. Broadband cholesteric films reflect, for example, right circularly polarized light and transmit left circularly polarized light. There is also a broadband cholesteric film that does the opposite.

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

The liquid crystal cell 76 for display was formed using the liquid crystal material which has negative dielectric anisotropy ((DELTA) epsilon <0), and used it as the vertically-aligned liquid crystal display element. In addition, the liquid crystal cell 55 of the eria division liquid crystal cell 77 was formed using the liquid crystal material which has a positive dielectric anisotropy ((DELTA) epsilon> 0), and set the twist angle to 90 degrees. In this figure, the alignment states of the liquid crystal molecules when voltage is not applied to both cells 76 and 77 are shown.

Linear polarizing plates were used as the upper, lower, and center polarizing plates 54a, 54b, 54i. The upper and center polarizing plates 54a and 54i were arranged in orthogonal nicols, and the center and lower polarizing plates 54i and 54b were arranged in parallel nicols. In the figure, the direction of the transmission axis of the polarizing plates 54a, 54b, 54i is indicated by an arrow.

The D-BEF 69 was disposed such that the reflection axis and the transmission axis of the upper polarizing plate 54a were parallel to each other.

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 oriented substantially perpendicular to the upper and lower substrates 50a and 50b when no voltage is applied. For this reason, light incident on the liquid crystal layer passes through the liquid crystal layer without changing the polarization direction.

When voltage is applied, the alignment state of the liquid crystal molecules in the non-display area is not changed from when no voltage is applied, but in the display area, the liquid crystal molecules are 45 ° in the in-plane direction with respect to the transmission axes of the upper and lower polarizing plates 54a and 54b. The light which is inclined toward the direction of and is incident on the liquid crystal layer is given a birefringence effect. The liquid crystal layer has an effect equivalent to that of the 1/2 wavelength plate, and the incident light is emitted from the liquid crystal layer by changing the polarization direction by 90 °.

On the other hand, the liquid crystal molecules of the liquid crystal cell 77 for dividing the area are twisted by 90 degrees 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, the light incident on the liquid crystal layer changes in the 90 ° polarization direction and passes through the liquid crystal layer.

Upon application of voltage, the liquid crystal molecules are oriented almost vertically between the upper and lower substrates 50a and 50b. Therefore, the light incident on the liquid crystal layer in the area to which the voltage is applied passes through the liquid crystal layer without changing the polarization direction.

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

Light generated from the multicolored front light 66 becomes linearly polarized light having a polarization direction in the transmission axis direction of the upper polarizing plate 54a and enters the liquid crystal layer 55.

In the non-display area (region where no voltage is applied), 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 multicolored front 66 that has passed through the liquid crystal layer 55 is 100% reflected 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 the viewer.

In the display area (area where voltage is applied), the alignment state of the liquid crystal molecules changes when no voltage is applied, so that light incident on the liquid crystal layer 55 exits the liquid crystal layer 55 by changing the polarization direction by 90 °. do. The polarization direction of the linearly polarized light exiting the liquid crystal layer 55 and the reflection axis direction of the D-BEF 69 are perpendicular to each other (parallel to the transmission axis direction of the D-BEF 69). For this reason, the linearly polarized light emitted from the liquid crystal layer 55 passes through the D-BEF 69 and the central polarizing plate 54I, propagates to the liquid crystal cell 77 for area dividing, and is lost by scattering or the like. Therefore, the light emitted from the multicolored front light 66 is not visually recognized by the viewer.

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

The light emitted from the multicolor backlight 56 becomes linearly polarized light having a polarization direction in the transmission axis direction of the lower polarizing plate 54b and enters the liquid crystal cell 77 for dividing an area.

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

In the area to which the voltage is applied, the light emitted from the multicolor backlight 56 emits the liquid crystal cell 77 for dividing the area without changing the polarization direction, so that the center polarizing plate is disposed in parallel with the lower polarizing plate 54b. 54i, it subsequently penetrates through the D-BEF 69 and enters the liquid crystal cell 76 for display.

In the display area of the display liquid crystal cell 76, when a voltage is applied to an electrode at a position corresponding to an area where light emitted from the multicolor backlight 56 is emitted, the light is polarized in the electrode position. This 90 ° change causes the display liquid crystal cell 76 to exit, and passes through the upper polarizing plate 54a, so that the viewer is visually recognized.

Therefore, in the non-display area, the light emitted from the multicolor front light 66 is visually recognized by the observer, and in the display area, the light emitted from the multicolor backlight 56 is visually recognized.

As described above, the liquid crystal display device according to the first exemplary embodiment may independently express the color tone of the non-display area with the multicolor front light 66 and the color tone of the display area with the multicolor back light 56 independently. By selecting the color of the 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 device according to the first embodiment, even when the multicolor front light 66 and the multi color back light 56 are lit at the same time, only one light is visible to the viewer for any one point. It is recognized. When the liquid crystal display device performs on / off two-value operation, simultaneous lighting of both rarely causes color mixing.

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

The compensating cell 70 and the liquid crystal layer 55 of the driving cell 71 are formed together using the same liquid crystal material having positive dielectric anisotropy (Δε> 0), and the respective cells 70 and 71 are formed. A horizontal alignment liquid crystal display device having a left twist angle of 90 degrees and a right twist angle of 90 degrees, respectively. The liquid crystal molecule alignment directions in the center of the thickness direction of the liquid crystal layers 55 of the cells 70 and 71 were perpendicular to each other, and the thicknesses of the liquid crystal layers 55 of both cells 70 and 71 were equal. In this figure, the orientation state of the liquid crystal molecules when no voltage is applied is shown.

In the display liquid crystal cell 76, the display operation was performed only by applying a voltage to the driving cell (lower cell) 71, but not energizing the compensation cell (upper cell) 70.

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

The operation of the liquid crystal display device according to the second embodiment will be described. As described above, since no energization is performed to the compensation cell 70, the liquid crystal molecules of the compensation cell 70 always maintain the state of the left twist angle of 90 degrees. Therefore, the light incident on the compensation cell 70 is emitted by changing the polarization direction to 90 ° to the left.

When no voltage is applied, the drive cell 71 emits incident light by changing the polarization direction to 90 ° to the left. That is, in the driving cell 71, the light is changed by 90 ° in the reverse direction of the compensation cell 70. Therefore, the light is emitted from the liquid crystal cell of the two-layer structure in the same polarization direction as when incident on the liquid crystal cell 70 of the two-layer structure.

However, when the voltage is applied, the alignment state of the liquid crystal molecules in the non-display area is not changed from when no voltage is applied, but in the display area, the alignment states of the liquid crystal molecules of the driving cell 71 change when the voltage is not applied (upper and lower side). Light perpendicular to the substrates 50a and 50b) and incident on the drive cell 71 are emitted from the drive cell 71 without changing the polarization direction. Therefore, the light exits the liquid crystal cell of the two-layer structure by making the polarization direction different from that when the light enters the liquid crystal cell of the two-layer structure.

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

Therefore, the liquid crystal display device according to the second embodiment operates in the same manner as the liquid crystal display device according to the first embodiment, and when no voltage is applied, light emitted from the multicolor front light 66 in all areas of the display section. This observer is visually recognized, and when the voltage is applied, the light emitted from the multicolor front light 66 is visually recognized by the observer in the non-display area, and is emitted from the multicolor back light 56 in the display area. The light is visually recognized by the viewer.

As a result of examining the liquid crystal cell of various torsion angles, the present inventors found that the liquid crystal display device according to the second embodiment is effective when the torsion angles of the compensation cell 70 and the driving cell 71 are 70 to 240 degrees. I found it to work.

The same effect was obtained even if the compensation cell (upper cell) 70 was replaced with Twistar, a product of Polar Techno Co., Ltd., which is a liquid crystalline polymer alignment retardation plate having an optical function equivalent thereto.

5 is a schematic exploded perspective view showing a liquid crystal display device according to a third embodiment. The liquid crystal display device according to the third embodiment is a liquid crystal display device having a phase difference plate 72 between an upper substrate 50a and an upper polarizing plate 54a of the liquid crystal cell 76 for display.

By properly determining the twist angle of the liquid crystal molecules, the thickness of the liquid crystal layer, the phase difference 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, and the upper side are appropriately determined. And liquid crystal elements composed of the central polarizing plates 54a and 54i, the D-BEF 69, and the retardation plate 72 were liquid crystal elements of the normal black type for light emitted from the multicolor backlight 56. . Here, the retardation plate 72 serves to adjust the color tone.

The detail of a structure is as follows.

The thickness of the liquid crystal layer 55 of the liquid crystal cell 76 for display was 6 micrometers, and RDP00333 by Dainippon-Inki Co., Ltd. was used as a liquid crystal material. The liquid crystal molecules were arranged in a torsional horizontal orientation with a torsional 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. In addition, the slow axis of the retardation plate 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 each centered in the thickness direction of the liquid crystal layer 55. The angle formed by the molecular orientation direction of was 140 °, 95 °, 70 °, 70 °.

In this figure, the alignment state of the contract molecule when voltage is applied is shown. In addition, the direction of the transmission axis of the upper and center polarizing plates 54a and 54i, the direction of the slow axis of the retardation plate 72, and the direction of the transmission axis of the D-BEF 69 are shown by the arrow.

Further, 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. It was set as the type liquid crystal cell. In addition, the center and lower polarizing plates 54i and 54b were orthogonal nicols.

In the third embodiment, one retarder 72 is used, but a plurality of retarders may be used. In addition, the biaxial optical anisotropy retardation plate may be used, without being limited to the uniaxial optically anisotropic phase difference plate.

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

6 is a schematic exploded perspective view showing a liquid crystal display device according to a fourth embodiment. The liquid crystal display device according to the fourth embodiment is similar to the liquid crystal display device according to the first embodiment shown in FIG. In the liquid crystal display device according to the first embodiment, the upper and center polarizers 54a and 54i are disposed outside the upper and lower substrates 50a and 50b which sandwich the liquid crystal layer 55 of the liquid crystal cell 76 for display. The D-BEF was inserted between the lower substrate 50b and the central polarizing plate 54i as a polarization separating and reflecting plate which is disposed and transmits or reflects incident light depending on the polarization state.

In the liquid crystal display device according to the fourth embodiment, first, a broadband cholesteric film is used instead of D-BEF as the polarization separation and reflection plate 67, and the lower substrate 50b and the center polarizer 54i of the liquid crystal cell 76 for display. ), Which differs from the liquid crystal display device according to the first embodiment.

In addition, in the liquid crystal display device according to the first embodiment, linearly polarizing plates are used as the upper and center polarizing plates 54a and 54i. In the liquid crystal display device according to the fourth embodiment, the upper linear polarizing plate 54e is used as the upper polarizing plate 54a. ) And the upper quarter wave plate (54 g) were combined.

The circularly polarizing plate with respect to the light from above was employ | adopted, and the center linear polarizing plate 54f and the central quarter wavelength plate 54h were combined as the center polarizing plate 54i. A circularly polarizing plate for light from below was employed.

The upper and center polarizing plates 54a and 54i are formed by arranging a quarter wave plate on the display liquid crystal cell 76 side together, and forming an angle between the transmission axis of the linear polarizing plate and the slow axis of the quarter wave plate. Was set to ± 45 °.

The transmission axes of the upper and center linear polarizing plates 54e and 54f were perpendicular to each other. However, the orientations of the transmission axes of the upper and center linear polarizing plates 54e and 54f may be arbitrary for the upper and lower substrates 50a and 50b.

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

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

Hereinafter, circularly polarized light in which the x component becomes ground with respect to y component is left circularly polarized light, and circularly polarized light in which true image is made into left circularly polarized light.

On the contrary, the upper polarizing plate 54a reflects the left circularly polarizing plate, the central polarizing plate 54i the right circularly polarizing plate, and the broadband cholesteric film 73 reflects the left circularly polarized light. It may be one that transmits right circularly polarized light. The circularly polarized direction of the upper polarizing plate 54a and the central polarizing plate 54i are reversed, and the circularly polarizing direction through which the broadband cholesteric film 73 is transmitted coincides with the circularly polarizing direction of the central polarizing plate 54i.

And the structure which adhere | attached the broadband cholesteric film and circularly polarizing plate is employ | adopted. NIPOCS manufactured by Ildong Electric Co., Ltd. and TRANSMAX manufactured by Melk Co., Ltd. are usually used on the backlight and adhered to the lower side of the liquid crystal cell. In this case, the broadband cholesteric film is disposed on the light side (the side opposite to the liquid crystal cell). In this embodiment, it differs from this in that a broadband cholesteric film is arrange | positioned at the liquid crystal cell side.

The liquid crystal layer 55 of the liquid crystal cell 76 for display was formed using the liquid crystal material which has negative dielectric constant anisotropy ((DELTA) (epsilon) <0), and was made into the liquid crystal cell of a vertical alignment type. This figure shows the alignment state of the liquid crystal molecules when no voltage is applied. In addition, the retardation of the liquid crystal layer 55 at the time of voltage application was made into 1/2 wavelength (for example, x component is 1/2 wavelength ground).

The light emitted from the multicolored front light 66 becomes light polarized in the transmission axis direction of the upper linear polarizing plate 54e and enters the upper quarter wave plate 54g, and the x component is equal to 1/4 wavelength. It receives the ground and becomes a circular polarization.

When no voltage is applied to the display liquid crystal cell 76, light incident on the liquid crystal layer 55 of the display liquid crystal cell 76 exits the liquid crystal layer 55 without changing the polarization state. Right circularly polarized light emitted from the multicolor front light 66 and exiting the upper quarter wave plate 54g exits the liquid crystal layer 55 as it is, and is reflected by the broadband cholesteric film 73. . The reflected light passes through the liquid crystal layer of the liquid crystal cell 76 for display as it is, and the y component receives 1/4 wavelength ground in the upper quarter wave plate 54g. For this reason, it becomes linearly polarized light of the same polarization component as incident light, is transmitted by the upper linear polarizing plate 54e, and is visually recognized by an observer. On the contrary, the light emitted from the multicolor backlight 56 and divided by each area in the area-dividing liquid crystal cell 77 and transmitted through the central linear polarizing plate 54f has an x component of 1 in the central quarter wave plate 54h. Since it receives the / 4 wavelength true image and passes through the liquid crystal layer as it is, the left circularly polarized light, and receives the 1/4 wavelength ground from the upper side 1/4 wavelength plate (54g), it becomes a linearly polarized light which rotated the polarization axis of the central polarizing plate by 90 °, It is shielded from the linear polarizing plate 54e and is not visually recognized by the viewer.

When the voltage is applied to the liquid crystal cell 76 for display, the alignment state of the liquid crystal molecules of the liquid crystal layer 55 of the liquid crystal cell 76 for display changes, so that the right circularly polarized light incident on the liquid crystal layer 55 of the display area It becomes left circularly polarized light and emits the liquid crystal layer 55. In addition, left circularly polarized light becomes right circularly polarized light and emits the liquid crystal layer 55.

The light emitted from the multicolor front light 66 is visually recognized by the viewer in the non-display area in the same shape as when no voltage is applied to the display liquid crystal cell 76. In the display area, the x component is 1/4 wavelength ground and 1/2 wavelength ground, and becomes left circularly polarized light, penetrating the broadband cholesteric film 73, and 1/4 wavelength at the lower 1/4 wavelength plate 54h. It is not visually recognized by an observer because it receives a true phase and penetrates the lower linear polarizing plate 54f.

On the other hand, the light emitted from the multicolor backlight 56 and divided by each area in the area for dividing the area of the area (77) and transmitted through the central linear polarizing plate 54f is the central quarter wave plate 54h and the liquid crystal layer ( 55), the upper 1/4 wavelength plate 54g receives 1/4 wavelength image, 1/2 wavelength ground, and 1/4 wavelength ground, respectively, and enters the upper linear polarizing plate 54e. Is recognized.

The liquid crystal element composed of the liquid crystal cell 76 for display, the upper and center polarizing plates 54a and 54i, and the broadband cholesteric film 73 has a normal black type with respect to light emitted from the multicolor backlight 56. It is a liquid crystal element. A phase difference plate (phase difference film) such as a visual compensation plate is not used between the display liquid crystal cell 76 and the upper or center polarizing plates 54a and 54i, but may be appropriately used if necessary. .

The operation of the liquid crystal display device according to the fourth embodiment is the same as the operation of the liquid crystal display device according to the first embodiment. Therefore, when no voltage is applied to the liquid crystal cell 76 for display, light emitted from the multicolor front light 66 is visually recognized by an observer in all regions of the display unit, and when voltage is applied to the liquid crystal cell 76 for display. In the non-display area, the light emitted from the multicolor front light 66 is visually recognized by the viewer, and the light emitted from the multicolor backlight 56 is visually recognized by the viewer in the display area.

The liquid crystal display device according to the fourth embodiment can also have the same effect as the liquid crystal display device according to the first embodiment.

7 is a schematic exploded perspective view illustrating a liquid crystal display device according to a fifth embodiment. In the fourth embodiment, a vertically aligned liquid crystal cell was used as the liquid crystal cell for display. In the fifth embodiment, the configuration includes a twist nematic compensation cell (upper cell) 70 and a twist nematic driving cell (lower cell) 71 disposed on the upper and center polarizing plates 54a and 54i, respectively. The liquid crystal display device according to the fourth embodiment is different in that a twisted nematic liquid crystal cell having a two-layer structure is used.

The liquid crystal layer 55 of the compensation cell 70 and the driving cell 71 are formed using the same liquid crystal material having positive dielectric anisotropy (Δε> 0) together, and each cell 70 (71). The horizontally aligned liquid crystal display elements having a left twist angle of 90 degrees and a right twist angle of 90 degrees are obtained, respectively. The liquid crystal molecular alignment directions in the center of the thickness direction of the liquid crystal layer 55 of each cell 70, 71 are orthogonal to each other, and the thickness of the liquid crystal layer 55 of both cells 70, 71 is Was equal.

In this figure, the orientation state of the liquid crystal molecules when no voltage is applied is shown. The retardation of the liquid crystal layer 55 of both cells 70 and 71 was made into one wavelength.

The display operation of the liquid crystal cell 76 for display was performed only by applying a voltage to the drive cell (lower cell) 71, but did not conduct electricity to the compensation cell (upper cell) 70.

The liquid crystal cell composed of the compensation cell 70, the driving cell 71, the upper and center polarizers 54a and 54i, and the broadband cholesteric film 73 is provided with respect to the light emitted from the multicolor backlight 56. It is a liquid crystal element of a normal black type.

The operation of the liquid crystal display device according to the fifth embodiment will be described. As described above, since the energization of the compensation cell 70 is not performed, the compensation cell 70 functions as a polarization rotor. Therefore, the right circularly polarized light incident on the compensation cell 70 becomes the left circularly polarized light and exits the compensation cell 70. In addition, the left circularly polarized light becomes the right circularly polarized light and exits the compensation cell 70.

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

Therefore, in the non-display area even when no voltage is applied to the driving cell 71 and when voltage is applied, the light incident on the liquid crystal cell (compensation cell 70 and the driving cell 71) having a two-layer structure is a right circularly polarized light. If it is the left circularly polarized light as it is, the left circularly polarized light will emit a liquid crystal cell having a two-layer structure. On the other hand, in the display area, when the voltage is applied, the right circularly polarized light becomes the left circularly polarized light and the left circularly polarized light becomes the right circularly polarized light to emit a liquid crystal cell having a two-layer structure.

Accordingly, the liquid crystal display device according to the fifth embodiment operates in the same manner as the liquid crystal display device according to the fourth embodiment, and when the voltage is not applied to the driving cell 71, the multicolor front light 66 is used in all areas of the display unit. The outgoing light is visually recognized by the observer, and when the voltage is applied to the driving cell 71, the light from the multicolor front light 66 is visually recognized by the observer in the non-display area, and the multicolor is displayed in the display area. Light from the backlight 56 can be visually recognized by the viewer.

As a result of examining the liquid crystal cell of various torsion angles, the present inventors found that the liquid crystal display device according to the fifth embodiment is practically used when the torsion angles of the compensation cell 70 and the driving cell 71 are 70 to 240 degrees. It was found to work effectively.

The same effect was obtained even when the compensation cell (upper cell) 70 was replaced with Twistar, a product of Polar Techno Co., Ltd., a liquid crystalline polymer alignment phase difference plate having an optical function equivalent thereto.

As mentioned above, although demonstrated according to the Example, the liquid crystal display element which concerns on this invention is not limited to these Examples. For example, in FIGS. 4 and 7, the upper and lower substrates 50a and 50b of the compensation cell 70 have upper and lower transparent electrodes 52a and 52b, respectively. These are not necessary if no voltage is applied to). In addition, although the compensation cell 70 was arrange | positioned upward and the drive cell 71 was arrange | positioned downward in the Example, these arrangement | positioning may be reversed.

In addition, although the liquid crystal display element which can perform segment display and dot display together was demonstrated in the Example, a segment type liquid crystal display element and a full dot type liquid crystal display element may be sufficient.

In addition, the retardation film (retardation film) is between the upper substrate 50a and the upper polarizing plate 54a. It is possible to insert into one or both of the lower substrate 50b and the central polarizing plate 54i.

8A and 8B, a method of driving a liquid crystal display device according to an embodiment will be described. The driving liquid crystal display element is, for example, the liquid crystal display element described with reference to FIGS.

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

Fig. 8A is a table showing the application / no application of the voltage to the electrodes of the display liquid crystal cell (the drive cell when the display liquid crystal cell is a two-layer structure). Those for each electrode corresponding to dots 88a to 88u and segment 89 shown in Fig. 2B are shown. In the figure, "on" indicates that voltage is applied through SB1 to SB3, and "off" indicates that no voltage is applied through SB1 to SB3.

Among the electrodes corresponding to the 20 dots of dots 88a to 88u, the voltage is applied to the electrodes corresponding to the eight dots of dots 88a to 88e, 88j, 88p, and 88u. When connected, it becomes "L". In addition, a voltage was also applied to the electrode corresponding to segment 89 indicating "ST". The dots forming the "L" shape and the segment of "ST" become the display area, and the dots and the background area other than the remaining display areas become the non-display area.

8B is a table summarizing the application of the voltage to the liquid crystal cell for dividing an area and the non-application, the point of the multicolored front light, the light off, the point of the multicolor back light, and the light off.

The application / no application of the voltage to the liquid crystal cell for dividing an area is shown for each electrode corresponding to the areas 86 and 87 shown in FIG. 2C. "On" indicates that the voltage is applied to the electrode corresponding to the corresponding SB, and "off" does not apply the voltage to the electrode corresponding to the corresponding SB. Indicates not.

In addition, about the example of a multicolor front light and a multicolor back light, "on" shows lighting and "off" shows light off. The lighting color is shown in parentheses next to "ON". No simultaneous lighting of both lights was performed.

The switching of the liquid crystal layer of the multi-color front light, the multi-color back light, and the liquid crystal cell for dividing an area was synchronized using a synchronizing circuit. Thereby, the mixed color of the illumination light in a display part can be avoided.

See the row in SB1. In SB1, blue light was emitted from the multicolored front light 66. In addition, the multicolor backlight 56 was turned off and light was not emitted. In the liquid crystal cell for dividing eria, the voltage was unapplied to both of the eria 86 and 87.

Since light is not emitted from the regions 86 and 87 of the liquid crystal cell for dividing the area, even if a voltage is applied to the electrode corresponding to the dot forming the "L" shape of the liquid crystal cell for display and the segment displaying "ST". The display of these parts (display area) is not performed.

On the other hand, blue light in the far front is incident on the non-display area.

See the row in SB2. In SB2, the multicolored front light 66 was turned off and light was not emitted. In addition, red light was emitted from the multicolor backlight 56. A voltage was applied to the electrode corresponding to eria 86 of the liquid crystal cell for dividing eria, and was unapplied to the electrode corresponding to eria 87.

The red light is emitted from the area 86 of the liquid crystal cell for dividing the area, but the light is not emitted from the area 87. In addition, the area 86 is defined corresponding to the formation positions of the electrodes corresponding to the dots 88a to 88u, and the light emitted from the area 86 is used for the display of the dots 88a to 88u. For this reason, the dot which forms the "L" shape of the display liquid crystal cell to which the voltage is not applied is displayed by the red light which exited the area 86.

See the row in SB3. In SB3, the multicolored front light 66 was turned off and light was not emitted. In addition, yellow light was emitted from the multicolor backlight 56. A voltage was not applied to the electrode corresponding to the eria 86 of the liquid crystal cell for dividing the eria, but to the electrode corresponding to the eria 87.

Yellow light is emitted from the area 87 of the liquid crystal cell for dividing an area, but light is not emitted from the area 86. Further, the area 87 is defined corresponding to the formation position of the electrode corresponding to the segment 89, and the light exiting the area 87 is used for the display of the segment 89. For this reason, the segment of "ST" of the display liquid crystal cell to which the voltage is applied is displayed by the yellow light which exited the area 87.

When the present inventors drive the liquid crystal display element by the driving method shown in Figs. A and 8b, in the display portion as shown in Fig. 2b, "L" by dots is red and "ST" by segments is In yellow, portions other than it (non-display area) were displayed in blue.

In the driving method of the liquid crystal display element according to the embodiment, in SB1, the multicolored front light was turned on to express the non-display area. In addition, in SB2 and SB3, the multicolor backlight 56 was turned on to represent the display area. Since the lighting colors of SB1, SB2, and SB3 were blue, red, and yellow, respectively, the non-display area was represented by blue, and the display area was represented by red and yellow.

Since the multicolored front light 66 and the multicolored back light 56 can emit light of any color, various colors can be displayed in both the display area and the non-display area. As shown in the embodiment, the display area can be displayed in a plurality of colors. For example, if three SBs for displaying a display area are provided, and light of a different color is emitted from the multicolor backlight in each SB, the display area can be displayed in three colors. Therefore, depending on the number of display units, it is possible to display in different colors for each display unit.

Since the liquid crystal cell for display is normal black, the background area can be displayed in black by turning off the multicolored front light through all the SBs. In addition, the display unit can be displayed in black by controlling the display unit (for example, one dot) by using a synchronous circuit so as not to display the illumination light through all the SBs. For this reason, when the SB for non-display area expression is included and one frame is divided into n SBs, the display in n + 1 colors including the non-display area color is possible.

Each display unit and background area can be displayed with light from the light only at one SB, so that color breaks can be prevented.

As also understood from the driving method described with reference to Figs. 8A and 8B, it is not necessary to use a liquid crystal cell corresponding to high-speed light emission for the display liquid crystal cell. Therefore, for example, a dot display cell of simple matrix driving can be employed, so that the manufacturing cost can be reduced.

On the other hand, since the high-speed correspondence is required for the area-dividing liquid crystal cell, it is preferable to perform a low duty, especially starting driving. Since the liquid crystal cell for dividing an area has a smaller number of pixels than the liquid crystal cell for display, it is easy to set it as a starting drive cell.

It is not essential that the liquid crystal cell for display, the liquid crystal cell for dividing an area, the multicolor front light, and the multi color back light all synchronize.

As mentioned above, although this invention which concerns on an Example was demonstrated, 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 are possible.

It can be used as a segment type, full dot type, composite display of segment display and dot display, and a driving method thereof.

According to the present invention, a liquid crystal display device capable of displaying various colors and a driving method thereof can be provided.

Claims (16)

A first substrate having a first electrode of a predetermined shape; A second substrate having a second electrode having a predetermined shape, disposed in parallel with the first electrical substrate, the first substrate including a first display unit and a second display unit for displaying at a position where the first electrode and the second electrode face each other. A second substrate having a plurality of display units defined therein and a background area defined at a position where the first and second electrodes do not face each other; A liquid crystal layer disposed between the first electrical substrate and the second substrate and capable of switching the alignment state by applying a voltage between the electrical first electrode and the second electrode; A first polarizing plate disposed on a side opposite to the side on which the liquid crystal side of the first substrate is disposed; A first light source disposed on a side opposite to the side on which the first substrate of the electric first polarizing plate is disposed; A transmissive / reflective plate which transmits or reflects incident light depending on the polarization state, which is disposed on the side opposite to the side on which the liquid crystal layer of the second substrate is disposed; A second polarizing plate arranged on the side opposite to the side on which the electric second substrate of the electric transmission and reflecting plate is disposed;  A first and second exit opening arranged on the side opposite to the side on which the electric transmission / reflector of the electric second polarizing plate is arranged and capable of displaying the electric first and second display units with the emitted light, respectively; 2 light source, Voltage application means for applying a voltage between the first electrode and the second electrode; A control circuit capable of time-dividing one frame into a plurality of subframes and emitting an electric first or second light source within each subframe when the period for displaying one image is one frame; The electrical transmission and reflection plate reflects light in a polarization state passing through the first polarizing plate and the electrical liquid crystal layer when no voltage is applied, and transmits light in a polarization state passing through the second polarizing plate. A liquid crystal display device of a normal black type for light emitted from an electric second light source, wherein light transmitted through an electric second polarizing plate, an electric transmission / reflection plate, and an electric liquid crystal layer when no voltage is applied is shielded by the electric first polarizing plate. The liquid crystal display device according to claim 1, wherein the electric first light source or the second light source can selectively emit a plurality of colors of light. The liquid crystal display device according to claim 1, wherein the first polarizing plate and the second polarizing plate are linear polarizing plates each having a transmission axis in a first direction and a second direction perpendicular to the first electrical direction. The liquid crystal display device according to claim 3, wherein the direction of the reflection axis of the electrical transmission / reflection plate and the first electrical direction are parallel to each other. An electric first polarizing plate is a circularly polarizing plate which transmits left circularly polarized light, an electric second polarizing plate is a circularly polarizing plate which transmits left circularly polarized light, or an electric first polarizing plate is a circularly polarizing plate which transmits left circularly polarized light. A liquid crystal display device characterized in that the two polarizing plates are circular polarizing plates that transmit right circularly polarized light. 6. The liquid crystal display device according to claim 5, wherein the first and second polarizing plates each comprise a linear polarizing plate and a quarter-wave plate. The liquid crystal display device according to claim 1, wherein the electric liquid crystal layer is sandwiched vertically between the electric first substrate and the electric second substrate in a voltage-free state. The liquid crystal display device of claim 1, further comprising a compensation liquid crystal layer disposed between the second electrical substrate and the electrical transmission / reflective plate, or between the first substrate and the first polarizer plate. The electric liquid crystal layer and the electric compensation liquid crystal layer include liquid crystal molecules that are horizontally twisted in opposite directions to each other in a voltage-free state, The alignment direction of the liquid crystal molecules located at the center of the thickness direction of the electrical liquid crystal layer and the alignment direction of the liquid crystal molecules located at the center of the thickness direction of the electric compensation liquid crystal layer are perpendicular to each other, A liquid crystal display device characterized by the same retardation of an electric liquid crystal layer and an electric compensation liquid crystal layer. The liquid crystal display device according to claim 8, wherein the twist angles of the liquid crystal molecules of the electric liquid crystal layer and the electric compensation liquid crystal layer are 70 to 240 degrees. The liquid crystal display device of claim 1, further comprising a retardation plate disposed between the first electrical substrate and the first polarizing plate, or between the second electrical substrate and the second electrical polarizer. The method of claim 1, wherein the second electric light source includes a light emitting device and a liquid crystal cell to which light emitted from the electroluminescent device is incident The electric liquid crystal cell, A third substrate having a third electrode of a predetermined shape; A fourth substrate having a fourth electrode having a predetermined shape, disposed in parallel with the third electrical substrate, the fourth substrate including an electrical first exit port and a second exit port at a position where the electrical third electrode and the electrical fourth electrode face each other. 4th board which is defined as the exit port to say, And a liquid crystal layer sandwiched between the third electrical substrate and the fourth electrical substrate. 12. The liquid crystal display device according to claim 11, wherein the electric control circuit synchronizes light emission of the electroluminescent device and switching of the alignment state of the electric liquid crystal layer between the third and fourth substrates. The electric control circuit according to claim 1, wherein the electric control circuit displays with light emitted from the first electrical light source in one subframe, and displays with light emitted from the second electrical light source in another subframe; Each of the units is characterized by controlling the light emission of the electric first light source and the light emission of the electric second light source so that the display is performed with light emitted from the first or second light source in at most one subframe in one frame. Liquid crystal display device. The liquid crystal display device according to claim 1, wherein the electric control circuit controls the electric first or second light source to emit light of different colors in all subframes of one frame. A second substrate having a first substrate having a first electrode of a predetermined shape and a second electrode of a predetermined shape, arranged in parallel with the first electrode, wherein the first electrode and the second electrode face each other. A second substrate having a plurality of display units including first and second display units for displaying on the second substrate and having a background area defined at positions where the first and second electrodes do not face each other; A liquid crystal layer arranged between the second substrate and the second substrate, the voltage being applied between the first electrode and the second electrode to switch the alignment state, and the side on which the liquid crystal side of the first substrate is disposed; A polarization state disposed on the opposite side to the side on which the first polarizing plate disposed on the opposite side, the first light source disposed on the opposite side to the side on which the first substrate of the electrical first polarizing plate is disposed, and the liquid crystal layer of the electrical second substrate are disposed A transmission / reflection plate that transmits or reflects incident light depending on The second polarizing plate disposed on the side opposite to the side on which the electric second substrate is disposed, and the side opposite to the side on which the electrical transmission and reflecting plate of the second polarizing plate is disposed, and the first and second electrical A second light source having first and second exit ports capable of displaying display units, voltage applying means for applying a voltage between the first electrode and the second electrode, and a period for displaying one image Has a control circuit capable of time-dividing one frame into a plurality of sub-frames and emitting an electric first or second light source within each sub-frame when the frame is one frame, and the electrical transmission / reflector includes an electrical first polarizing plate and a voltage. Reflects light in a polarization state that passes through the non-applied electrical liquid crystal layer, transmits light in a polarization state that passes through the second polarizing plate, and performs an electrical second polarizing plate, an electrical transmission / reflection plate, and an electrical liquid crystal layer in the absence of voltage. Penetrated Is, as a driving method of a liquid crystal display element in the normal black type with respect to light emitted from electrical second light source, which light shield electrically the first polarizing plate, In any subframe, performing a display with light emitted from the first electrical light source; In the other sub-frames, performing the display with the light emitted from the electric second light source Wherein each of the electrical display units is displayed with light emitted from the first or second light source in at most one subframe in one frame. The method of driving a liquid crystal display device according to claim 15, wherein the electric first or second light source is controlled to emit light of different colors in all subframes of one frame.

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