JPH04131828A - Color liquid crystal display device - Google Patents

Abstract

PURPOSE:To display a predetermined display area in plural kinds of color by applying a 1st and a 2nd segment and a 1st and a 2nd common electrode with a plus or minus voltage individually by a driving means. CONSTITUTION:A segment-side transparent electrode consists of the 1st segment electrode 14 formed corresponding to one of three color filters and the 2nd segment electrode 14 formed corresponding to the two color filters other than the color filter corresponding to the 1st segment electrode 14. Further, a common-side transparent electrode consists of the 1st common electrode 19 formed corresponding to one color filter other than the color filter corresponding to the 1st segment electrode 14 and the 2nd common electrode 20 formed corresponding to the two color filters other than the color filter corresponding to the 1st common electrode 19. The combination of the positive polarity and negative polarity of rectangular voltages applied to the electrodes 14 and 15, and electrodes 19 and 20 is changed. Consequently, the diversity of the display is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a segment type color liquid crystal display device capable of displaying predetermined characters, figures, etc. in color.

Conventional technology When forming a display area in a liquid crystal display device, a segment electrode formed on a segment-side transparent substrate and a common electrode formed on a common-side transparent substrate are arranged so that the two transparent substrates face each other. so that they overlap when placed together. This overlapping portion becomes the display area. Furthermore, a plurality of color filters of different colors are formed on the liquid crystal layer side surface of one of the pair of transparent substrates constituting the liquid crystal display device, and in the display area, for example, the segment side transparent electrodes are colored. Color display can be performed by forming segment electrodes corresponding to each filter and electrically connecting segment electrodes formed corresponding to color filters of the same color.

FIG. 8 is an enlarged plan view of the segment-side transparent substrate 1 in a conventional color liquid crystal display device. On the segment side transparent substrate 1, there are three types of color filters formed in fine rectangular shapes, for example, a red filter R and a green filter G.
and a blue filter B are formed. In FIG. 8, a first segment electrode is formed in a region corresponding to the blue filter B, and a second segment electrode 3 is formed in a region corresponding to the red filter R. Therefore, when the first segment electrode 2 is turned on (voltage applied state), the region corresponding to the blue filter B is turned on, and when the second segment electrode 3 is turned on, the region corresponding to the red filter R is turned on. become.

Here, it is assumed that the common electrode is formed in a region including at least the first and second segment electrodes 2.3.

In the liquid crystal display device using the segment-side transparent substrate 1 shown in FIG. 8, by arranging the polarizing plates so as to form crossed Nicols, it is possible to perform a so-called normally white display in which light is transmitted when no voltage is applied. can. Therefore, white is displayed as the background color on the liquid crystal display device when no voltage is applied. Turn on the first segment electrode 2
In this state, the alignment state of liquid crystal molecules in the liquid crystal layer corresponding to color filter B changes, and light is blocked. As a result, light blue is displayed in the display area due to the mixture of red light and green light. Further, by turning on the second segment electrode 3, red light is blocked, and light blue is displayed in the display area by a mixture of green light and blue light. Furthermore, when both the first and second segment electrodes 2.3 are turned on, red light and blue light are blocked and green is displayed in the display area. Therefore, the aforementioned liquid crystal display device can display four types of colors: white, yellow, light blue, and green.

In order to display any color among the eight colors (white, light blue, purple, yellow, blue, green, red, black) by combining the three colors red, green, and blue, three types of color filters are required. As shown in FIG. 9, first, second and third segment electrodes 4.5.6 are formed for each of the R, G and B filters, and the first, second and third segment electrodes 4,5.
．． 6 must be driven individually, and three signal lines are required to supply voltage to each segment electrode.

Problem to be Solved by the Invention However, in order to wire the three signal lines electrically independently as shown in FIG. 9, the third segment line 8i! It is necessary to make the width of the signal line 6a that sequentially connects the signal lines 6 to be extremely thin. A wiring method using a normal transparent conductive film cannot achieve this because the resistance value becomes extremely high.

For example, in a typical liquid crystal display device, the color filter is selected to have a width of 80 μm and a length of 300 μm. The interval between each color filter is 30 μm, and the transparent electrode (IT○,
The sheet resistance value of the indium tin oxide (indium tin oxide) is selected to be approximately 40Ω/mouth. In this case, if one attempts to arrange one transparent electrode at an interval of 30 pm as shown in Figure 9, the width of the transparent electrode will be 10 μm, the interval between the transparent electrodes will be 5 μm, and the length of the single color filter will be 10 μm. The resistance value of the transparent electrode corresponding to a diameter of 300 μm is 40Ω x 300/10 = 1.2, and the resistance value of the transparent electrode that connects multiple color filters is 1.2, which is 10 to 300 times Ω. Become. Therefore, electrical driving becomes almost difficult due to the high resistance value of the transparent electrode.

Also, in terms of the manufacturing process of liquid crystal display devices, 30c
It is very difficult to pattern transparent electrodes with a width of 10 μm at intervals of 5 μm on a transparent substrate measuring 45 cm square.

Therefore, four types of color display are normally performed by electrode arrangement and wiring connections as shown in FIG. However, in this case, for example, in a liquid crystal display device set to normally white display, purple, blue, red,
The four colors of black could not be displayed. In this way, conventional color liquid crystal display devices are limited in the types of colors that can be displayed.
Display diversity was lacking.

An object of the present invention is to provide a color liquid crystal display device that can display a predetermined display area in a plurality of colors.

Means for Solving the Problems The present invention provides: a pair of light-transmitting substrates provided with a liquid crystal layer sandwiched therebetween; one of the pair of light-transmitting substrates is provided over the entire surface of the liquid crystal layer side of one of the pair of light-transmitting substrates; A plurality of color filters that select one color of transmitted light from red, green, or blue, a segment-side transparent electrode provided in a predetermined display area on the liquid crystal layer side of the transparent substrate on one side, and a transparent substrate on the other side. a common-side transparent electrode provided in an area including at least the display area on the liquid crystal layer side of the screen, and a driving means for individually applying a voltage of positive or negative polarity to the segment-side transparent electrode and the common-side transparent electrode. The segment-side transparent electrode includes: a first segment electrode formed corresponding to any one of the three color filters; and two color filters other than the first segment electrode.
and a second segment electrode formed corresponding to one color filter, and the common side transparent electrode is formed of one of the three color filters other than the color filter corresponding to the first segment electrode. A color characterized by comprising a first common electrode formed corresponding to a color filter, and a second common electrode formed corresponding to two color filters other than the color filter corresponding to the first common electrode. It is a liquid crystal display device.

Function According to the present invention, the first segment electrode is formed to correspond to, for example, a red color filter among three types of color filters of red, green, and blue, and the second segment electrode is formed to correspond to, for example, a green and blue color filter. formed corresponding to the filter. Further, the first common electrode is formed to correspond to, for example, a blue color filter, and the second common electrode is formed to correspond to a red and green color filter. Positive or negative voltages are individually applied to these first and second segment electrodes and the first and second common electrodes by a driving means.

Table 1 below shows the correspondence between the polarity of the voltage applied to the segment-side transparent electrode and the common-side transparent electrode and the display state (ON state R or OFF state). In Table 1, Sl represents the first segment electrode, S2
represents the second segment electrode, C1 represents the first common electrode, C2 represents the second common electrode, "positive" represents applying a positive polarity square wave voltage, and "negative" represents negative polarity. This represents applying a rectangular wave voltage of .

Table 1 As shown in Table 1 above, the ON state i<voltage applied state)10FF state (voltage not applied state) of the liquid crystal layer corresponding to each of the red, green, and blue color filters can be set arbitrarily. Thus, by combining the three colors red, green, and blue, eight colors can be displayed in the display area.

Embodiment FIG. 1 is a sectional view of a color liquid crystal display device 11 which is an embodiment of the present invention, FIG. 2 is an enlarged plan view of a transparent substrate 12, and FIG. 3 is an enlarged plan view of a transparent substrate 13. It is a diagram.

The color liquid crystal display device 11 includes a pair of transparent substrates 11 and 12.
has.

First and second segment electrodes 14 and 15 are formed on one surface of the transparent substrate 12. The first segment electrode 14 is one of three color filters to be described later.
One, for example, is formed in a region corresponding to the red filter R. The second segment electrode 15 is formed in a region corresponding to two filters other than the color filter corresponding to the first segment electrode 14, here a green filter G and a blue filter B.

An organic alignment film 16 made of polyimide resin or the like is formed on one surface of the transparent substrate 12 on which the first and second segment electrodes 14 and 15 are formed.

A color filter 18 is formed on one surface of the transparent substrate 13. The color filter 18 includes three color filters (red filter R1, green filter G, and blue filter B).
) and a black light shielding layer B formed in the gap between each filter.
It consists of L.

Each color filter R, G, B has a width of 80 μm, for example.
The length is chosen to be 300 μm. The spacing between each color filter is chosen to be 30 μm.

First and second common electrodes 19 and 20 are formed on the color filter 18. One first common electrode is formed in a region corresponding to any one of the three color filters other than the color filter corresponding to the first segment electrode 14, in this example, the blue filter B. . The second common electrode 20 is formed in a region corresponding to two filters other than the color filter corresponding to the first common electrode 19, here a red filter R and a green filter G.

Color filter 18 and first and second common electric fi 19
．． An organic alignment film 17 made of polyimide resin or the like is formed on one surface of the transparent substrate 13 on which 20 is formed.

The transparent substrates 12, 13 are arranged such that the surfaces on which the organic alignment WAs 16, 17 are formed face each other. The liquid crystal layer 21 is interposed between the transparent substrates 12 and 13 and sealed with a sealant 22. The layer thickness of the liquid crystal layer 21 is selected to be 4 μm to 30 μm.

Polarizing plates 23 and 24 are arranged on the surfaces of the transparent substrates 12 and 13 opposite to the surfaces on the liquid crystal layer 21 side, respectively. The polarizing plates 23 and 24 are arranged, for example, in crossed Nicols.

The color liquid crystal display device 11 shown in FIG. 1 is constructed in the following order: transparent substrate 13 - color filter 18 - first and second common electrodes 8i 19.20 - alignment film 17. 1 and 2nd common electrode 19
．． 20 - color filter 18 - alignment film 17 may be configured in this order, and further transparent substrate 13 - color filter 18
- Top coat layer (transparent insulating layer) - first and second common electrodes 19, 20 - alignment film 17 may be configured in this order. Furthermore, the color filter 18 may be formed on the transparent substrate 12.

In this embodiment, the first segment electrode 14 is a red filter R, the second segment electrode 15 is a green filter G and a blue filter B, one first common electrode is a blue filter B, and the second common electrode 20 is a red filter. Although the filter R and the green filter G are formed to correspond to each other, the combination of each electrode and the corresponding filter is not limited to this.

FIG. 4 is a block diagram showing the electrical configuration of the color liquid crystal display device 11. A backlight 29 is arranged on the opposite side of the polarizing plate 24 from the transparent substrate 13. The backlight 29 includes a reflection case 25 and a cold cathode tube CCFT 26.
It consists of:

Between the backlight 29 and the color liquid crystal display device 11, a homogenizing reflector 27 for producing uniform light source light and a light reflector 28 made of milky white plastic or the like are arranged. The light from the CCFT 26 is transmitted to the color liquid crystal display device 1.
1 and the first and second segment electrodes 14.1
5 and the first and second common electrodes 19 and 20 to control the transmission/blocking of light by selectively applying a square wave voltage of positive or negative polarity to the predetermined display area in a desired color. can be displayed.

The positive polarity rectangular wave voltage from the inverter power supply 31 is applied to the terminal 5EG of the color liquid crystal display device 11 via the drive circuit 35.
I, 5EG2. Supplied to COMI and C0M2. The drive circuit 35 includes an amplifier 3234, a phase inverter 33 including an amplifier, and polarity inverting switches SWI to SW4.

The polarity inversion switches SW1 to SW4 output the input signal as is when a signal is input from one terminal, and invert the polarity of the input signal when input from the other terminal. Here, it is assumed that all polarity reversal switches are connected in the same direction.

A positive rectangular wave voltage from the inverter power supply 31 is applied to the terminal 5EGI connected to the first segment electrode via the polarity reversal switch SWI, and is applied to the second segment electrode 15 via the amplifier 32 and the polarity reversal switch SW2. The first common is connected to the terminal 5EG2 via the phase inverter 33 and the polarity inverting switch SW3.
9 and is further applied to a terminal C0M2 connected to the second common electrode 20 via a phase inverter 33, an amplifier 34, and a polarity inversion switch SW4.

5 and 6 are diagrams showing applied voltage waveforms applied to each electrode of the color liquid crystal display device 11. FIG. FIG. 5 shows the applied voltage waveform applied to the region corresponding to the red filter R. As shown in FIG. 5(1), the terminal 5
A positive rectangular wave voltage is applied to EGI (first segment electrode 14), and terminal C0M2 (second common electrode 2) is applied to EGI (first segment electrode 14).
0), a negative polarity rectangular wave voltage is applied. Therefore, by adding the square wave voltages of positive polarity and negative polarity, the liquid crystal layer corresponding to the color filter R has a threshold voltage vt
A voltage exceeding h is applied, and it becomes an ON state.

Further, as shown in FIG. 5 (2), by applying a positive polarity rectangular wave voltage to the terminal SEG1 and a positive polarity voltage to the terminal C0M2, the liquid crystal layer is Since a voltage lower than the threshold voltage vth is applied to , it becomes OFF state.

FIG. 6 shows the applied voltage waveform applied to the liquid crystal layer in the area corresponding to the green filter G. As shown in FIG. 6 (1), terminal 5EG2 (second segment electrode 15)
A positive square wave voltage is applied to the terminal C0M2 (
A negative polarity rectangular wave voltage is applied to the second common electrode 20). Therefore, by adding the positive polarity and negative polarity rectangular wave voltages, a voltage exceeding the threshold voltage vth is applied to the liquid crystal layer, so that the liquid crystal layer becomes in an ON state. Further, by reversely connecting the polarity reversing switch SW4, a positive rectangular wave voltage is applied to the terminal C○M2. With this, the 6th
As shown in FIG. 2, a voltage that does not exceed the threshold voltage vth is applied to the liquid crystal layer corresponding to the green filter G, so that it is in the OFF state.

5 and 6, by applying a positive rectangular wave voltage to the terminal 5EG2 and applying a negative rectangular wave voltage to the terminal COMI, the liquid crystal layer in the area corresponding to the blue filter B is Since a voltage exceeding the threshold voltage vth is applied to , it enters the ON state. Furthermore, by reversely connecting the polarity reversing switch SW3 and applying a positive square wave voltage to the terminal COMI, the liquid crystal layer has a threshold voltage V
Since a voltage lower than th is applied, it becomes an OFF state.

Table 2 below shows the segment electrodes 14 when normally white display (indicated by NW) and normally black display (indicated by NB) is set in a color liquid crystal display device.
．． 1.5 and the polarity of the voltage applied to the common electrodes 19, 20 and the display colors are shown.

In Table 2, rOFFJ indicates that no voltage is applied, but it is also possible to apply a rectangular wave voltage with the polarity listed in parentheses.
The same operation can be performed even if everything is reversed.

(Leaving space below) Table 2 As shown above, according to this embodiment, electrodes can be formed on the transparent substrates 12 and 13 using conventional transparent electrode patterning technology, and are compatible with color filters R, G, and B. 0N10FF control can be performed individually for each region. As a result, eight colors can be displayed on the color liquid crystal display device 11 by arbitrarily combining the three colors red, green, and blue. This greatly improves the display diversity of the color liquid crystal display device 11.

Furthermore, patterning of the transparent electrodes on the transparent substrates 12, 13 can be performed using conventional manufacturing techniques, and the color liquid crystal display device 11 can be manufactured at low cost without increasing costs.

FIG. 7 is a sectional view showing another embodiment of the present invention. This embodiment is similar to the previous embodiment, and corresponding components are given the same reference numerals. The feature of this embodiment is that the color filter 18 is provided on the transparent substrate 12. This embodiment also has the same effects as described above.

Effects of the Invention As described above, according to the present invention, it is no longer necessary to form transparent electrodes, which are individually formed on each color filter, only on one transparent substrate, as explained in the related art, and a high-precision patterning technique can be realized. The segment-side transparent electrode and the common-side transparent electrode can be formed on each transparent substrate by conventional patterning techniques without the need for . Furthermore, by changing the combination of positive and negative polarities of the rectangular wave voltages respectively applied to the first and second segment electrodes and the first and second common electrodes, red, green,
By arbitrarily combining the three colors of blue, eight colors can be displayed. This greatly improves the display diversity of the color liquid crystal display device.

[Brief explanation of the drawing]

FIG. 1 shows a color liquid crystal display device 1 which is an embodiment of the present invention.
2 is an enlarged plan view of the transparent substrate 12, FIG. 3 is an enlarged plan view of the transparent substrate 13, and FIG. 4 is a block diagram showing the electrical configuration of the color liquid crystal display device 11.
5 and 6 are diagrams showing voltage waveforms applied to each electrode of the color liquid crystal display device 11, FIG. 7 is a sectional view showing another embodiment of the present invention, and FIGS. 8 and 9 are diagrams showing the conventional FIG. 3 is a plan view for explaining an example. 11 - Color liquid crystal display device, 12.13... Transparent substrate, 14... First segment electrode, 15... Second segment electrode, 18... Color filter, 19... First common electrode, 20 ... Second common electrode, 21 ... Liquid crystal layer, 31 ... Inverter power supply, 32. 34 ... Amplifier, 33 ... Phase inverter, 35 ... Drive circuit, R.
...Red filter, G...Green filter, B...Blue filter, SW1-SW4...Polarity reversal switch agent Patent attorney Number of strokes Keiichi 5EGI (f-) SEGl (gradient diagram

Claims (1)

[Scope of Claims] A pair of light-transmitting substrates provided with a liquid crystal layer sandwiched therebetween, and a light-transmitting substrate provided over the entire surface of one of the pair of light-transmitting substrates on the liquid crystal layer side, and transmitting transmitted light in red, A plurality of color filters selected from either green or blue; one segment-side transparent electrode provided in a predetermined display area on the liquid crystal layer side of the translucent substrate; and the other segment-side transparent electrode provided on the liquid crystal layer side of the translucent substrate. a common-side transparent electrode provided in an area including at least the display area; and a driving means for individually applying a voltage of positive or negative polarity to the segment-side transparent electrode and the common-side transparent electrode, and the segment side The transparent electrodes include a first segment electrode formed corresponding to any one of the three color filters, and two other color filters other than the first segment electrode.
and a second segment electrode formed corresponding to one color filter, and the common side transparent electrode is formed of one of the three color filters other than the color filter corresponding to the first segment electrode. A color characterized by comprising a first common electrode formed corresponding to a color filter, and a second common electrode formed corresponding to two color filters other than the color filter corresponding to the first common electrode. LCD display device.