JPH0455828A - Color liquid crystal display device - Google Patents

Abstract

PURPOSE:To allow the changeover of only the background colors by selecting the color selecting members which produce the same colors as the colors produced by the color selecting members selected at the time of the impression/shut off of a display signal to a 2nd liquid crystal display element, at the time of the shut off/impression of the display signal to a 1st liquid crystal display element. CONSTITUTION:The other driving means 41 which controls the 1st liquid crystal display element 22 in correspondence to the operation of one driving means 40 to impress the display signal to the transparent electrodes of the 2nd liquid crystal display element 23 and shutting off the signal impression operates in the following manner. This driving means impresses the display signal to the color selecting member to be selected at the time of the impression/ shut off of the display signal to the 2nd liquid crystal display element 23 so as to select the color selecting members which produce the same colors as the colors produced by the color selecting members selected at the time of the impression/shut off of the display signal, at the time of the shut off/impression of the display signal. The display colors in the display regions do not change and only the background colors are changed over even if the display colors of the outside regions of the display region of the 1st liquid crystal display element 22 are changed to the complementary colors thereof by the impression/shut off of the display voltage to the 2nd liquid crystal display element 23.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a color liquid crystal display device using two-layer liquid crystal display elements.

Conventional Technology In a liquid crystal display device that performs color display, band-shaped or mosaic-shaped color filters are provided on a translucent substrate, alternately for red, green, and blue over the entire display area. 2. Description of the Related Art Liquid crystal display devices in which polarizing plates are arranged on each surface are known. In such a liquid crystal display device, depending on whether the polarizing plate is in a so-called crossed nicole state or in a parallel nickel state, there is a normally white display in which the display is white when the display voltage is cut off and black when the display voltage is applied, and vice versa. You can choose between black and white display.

In the case of a normally black display, the light incident on the liquid crystal display becomes elliptically polarized light due to the optical rotation dispersion phenomenon in the liquid crystal.
Even when the display voltage is cut off, light leaks through the liquid crystal display device, resulting in a decrease in display contrast.

In order to solve this problem, a liquid crystal display device having a two-layer structure including a liquid crystal display element for display and a liquid crystal display element for compensation has been developed.

FIG. 9 is a sectional view of a conventional liquid crystal display device 1. As shown in FIG. The liquid crystal display device 1 includes a liquid crystal display element 2 for display and a liquid crystal display element 3 for compensation, and transparent common electrodes 5a, 5b, 5c and segments are provided on a pair of glass substrates 4a, 4b of the liquid crystal display element 2. Electrodes 6a, 6b, and 6C are formed, and a color filter 7 is formed over the entire surface of the glass substrate 4b.

The color filter 7 has a structure in which, for example, a large number of fine band-shaped filters of red, green, and blue colors are alternately adjacent to each other and formed over almost the entire surface of the glass substrate 4b. An alignment film 8a is formed by covering almost the entire surface of such glass substrates 4a and 4b.
, 8b are formed, for example, a twisted nematic liquid crystal layer 9 is injected therein, and a sealing material 1o is formed around the layer 9.
is sealed.

On the other hand, alignment films 12a and 12b are formed on the glass substrate 11811b of the liquid crystal display element 3, and between them there are
A liquid crystal layer 13 of the Litziste Notonemateink type is injected, and the surrounding area is sealed with a sealing material 14. Deflection plates 15a and 15b are disposed on opposite surfaces of the glass substrates 11a and llb, respectively.

The liquid crystal display element 3 has: (1) a function to compensate for the refractive index difference between normal light and extraordinary light in the liquid crystal display element 2; (2) a function to compensate for optical rotational dispersion in the liquid crystal display element 2;
One of the functions that implements the functions in the item is set. Such a liquid crystal display device W1 has a polarizing plate 15 to be used.
The arrangement of the deflection plates 15a and I5b is selected so that when a and 15b are in a so-called crossed Nicols state, a normally black display is obtained, and when they are in a parallel Nicols state, a normally white display is obtained.

Here, each region of the color filter corresponding to the segment electrodes [i6a, 6b, 6c] is a color filter 7R, 7 that selectively transmits red, green, and blue light, respectively.
G, 7B (assuming that the shoulder plates 15a, 15b are arranged in a so-called normally black state).

At this time, the segments are arranged as shown in Shape 1, State 2, State 3, and State 4 in the Example 1 column of Table 1 below, depending on the application/cutoff state of the display voltage to the poles 6a, 6b, and 6c. It is possible to display four colors. Here, state 1.23 indicates each case where the segment electrodes 6b and 6c are connected in common, the segment electrodes 6a and 6c are connected in common, or the segment electrodes 8i and 6a and 6b are connected in common. , four-color display is possible for each example.

(The following is a blank space) Table 1 Problems to be Solved by the Invention In the liquid crystal display device 1 described above, in order to switch between normally black display and normally white display, almost all of the glass substrates 11a and llb of the liquid crystal display element 3 are provided. A technique is envisaged in which a transparent electrode is formed over the entire surface and switching between application and disconnection of a display voltage to this transparent electrode is envisaged. The case where the display voltage is cut off corresponds to the above-mentioned normally black state. When a transparent electrode is formed on the liquid crystal display element 3 and a display voltage is applied, the display state of the liquid crystal display device 1 becomes a so-called normally white state, and the transmitted light of each red, green, and blue color is shown in Table 2 below. The transparent suspension is selected as follows.

(Margin below) Table 1 In this case, in response to switching from normally black display to normally white display, that is, the background color is switched from black to white, for example, the segment electrode 6a in Table 1 A display voltage was applied only to segment: 2i [i6b, 6c (R,
G, B): <ON, OFF, 0FF), the display color was red, even though the voltage application/cutoff state of the segment electrodes 6a to 6c in the liquid crystal display element 2 did not change. In one example, the display color changes to light blue, which is a complementary color of red, and the other display colors, light blue and white in 111gI, similarly change to red and black.

The same applies to the display colors in the other Example 2 and Example 3 columns. There is a problem in that the display diversity of this diagonal color liquid crystal display device is limited.

An object of the present invention is to provide a color liquid crystal display device that can solve the above-mentioned technical problems and greatly expand display diversity.

Means for Solving the Problems The present invention provides a plurality of colors of light that are formed between a pair of light-transmitting substrates at least within a predetermined display area to predetermine transmitted light.
A plurality of color selection members each selected individually, a transparent electrode formed for each color selection member, a first liquid crystal display element with a liquid crystal layer interposed therebetween, and at least the display area between a pair of transparent substrates. a second liquid crystal display element interposing a transparent electrode and a liquid crystal layer over a region corresponding to the second liquid crystal display element; one drive means for applying/blocking a display signal to the second liquid crystal display element; Corresponding to the blocking operation, for the color selection member selected when the display signal is applied/blocked, when the display signal is blocked/applied, the same color as the color selected by the color selection member selected when the display signal is applied/blocked. This is a color liquid crystal display device characterized in that it includes a second driving means for selecting a color selection member that realizes.

Function: The color liquid crystal display device according to the present invention is a first color liquid crystal display device for color display.
It is configured to include a liquid crystal display element and a second liquid crystal display element for compensation. The driving means controls the first liquid crystal display element M in response to the operation of applying/cutting off the display signal to the transparent electrode of the second liquid crystal display element.The other driving means applies the display signal to the second liquid crystal display element. When the display signal is cut off and the display signal is cut off, a color selection member that achieves the same color as the color selected by the color selection member selected when the display signal is applied and cut off is selected. Apply the display signal as shown.

As a result, even if the display color in the area outside the display area of the first liquid crystal display element is changed to its complementary color by applying/cutting off the display voltage to the second liquid crystal display element, the display inside the display area It is possible to realize an operation of switching only the background color without changing the color. This greatly expands the variety of displays.

Embodiment FIG. 1 is a sectional view of a color liquid crystal display device 21 which is an embodiment of the present invention. The liquid crystal display device 21 has two twisted nematic mode liquid crystal elements, a color display liquid crystal element 22 and a compensation liquid crystal element 23.

The color display liquid crystal element 22 has a pair of transparent substrates 24a and 24b made of glass, acrylic resin, etc., and a color filter layer 25 is provided on one surface of the transparent substrate 24a over almost the entire surface.

A plurality of segment electrodes 26 having translucency are formed on the color filter layer 25, and the segment electrodes 26
On one surface of the transparent substrate 24b, a plurality of common electrodes 28 having translucent properties are formed on one surface of the transparent substrate 24b, covering at least the area including the segment electrodes 26. The alignment film 2 is formed on the transparent substrate 24b on which the common electrode 28 is formed.
7b is formed. The transparent substrates 24a and 24b are arranged such that the surfaces on which the alignment films 27a and 27b are formed, respectively, face each other. The twisted nematic liquid crystal layer 29 is injected between the transparent substrates 24a and 24b and sealed with a sealing resin 30.

Polyimide resin is used for the alignment films 27a and 27b. The orientations M27a and 27b are formed with a layer thickness of, for example, 600 mm, and are made of nylon fabric, for example, so that the orientation direction of the liquid crystal molecules is twisted by 90 degrees on the transparent substrates 24a and 24b, forming a levorotatory liquid crystal layer. Rubbed.

In order to keep the distance between the transparent substrates 24a and 24b constant,
A plastic spacer (not shown) is sandwiched between the substrates 24a and 24b. With this spacer,
The distance between the substrates 24a and 24b is set to, for example, 5 μm. The sealing resin 30 for sealing the two liquid crystal layers is
For example, epoxy resin. For the liquid crystal layer 29, for example, a phenylcyclohexane mixed liquid crystal is selected. Furthermore, cholesteric nonenate is added to this liquid crystal, giving it levorotatory properties.

The compensation liquid crystal element 23 has transparent substrates 31a and 31b made of glass, acrylic resin, etc.
, 31b, transparent electrodes 42, 43 are formed over almost the entire surface of each of them. Furthermore, the transparent electrode 42
．． Alignment films 32a and 32b are formed on 43, respectively. Transparent substrates 31a, 31b are alignment films 32a, 32b.
are arranged such that the surfaces on which they are formed face each other. Twisted nematic liquid crystal layer 33 is interposed between transparent substrates 31 a and 31 b and sealed with seal resin 34 . The alignment film 32a32b is made of polyimide-based resin, and rubbed between the transparent substrates 31a and 31b so that the alignment directions of liquid crystal molecules are twisted by 90 degrees to each other to form a dextrorotatory liquid crystal layer.

For the liquid crystal layer 33, phenylcyclohexane-based mixed liquid crystal was used as in the display liquid crystal element 22 described above. CD-15 (manufactured by Merck & Co., Ltd.) is added to this liquid crystal as a dextrorotatory chiral substance. As in the case of the display liquid crystal element 22 described above, the transparent substrates 31a and 31b are overlapped with a plastic spacer interposed therebetween. Transparent substrates 31a, 31
The spacing between b is selected to be 5 μm, for example.

A deflection plate 35 is provided on the surface of the transparent substrate 24b opposite to the liquid crystal layer 29, and a deflection plate 36 is provided on the surface of the transparent substrate 31a opposite to the liquid crystal layer 33. These deflection plates 35 and 36 are arranged in a crossed Nicols configuration.

Further, a drive circuit 40, which is a driving means, outputs display signals to transparent electrodes 42 and 43 of the liquid crystal element 23, as will be described later.
A drive circuit 41 is provided as the other drive means for outputting a display signal to the electrodes 26 and 28 of the liquid crystal element 22, as will be described later. Drive circuits 40 and 41 are control circuits 47
It is driven by a signal outputted from as will be described later.

FIG. 2 is a plan view of the liquid crystal display device 21. FIG. In the liquid crystal display device 21, segment electrodes 26 formed in, for example, a rectangular shape are arranged to form a Japanese character, and two such Japanese character segments are arranged, for example.

FIG. 3 is a plan view of the transparent substrate 24a, and FIG. 4 is a plan view of the transparent substrate 24a.
This is an enlarged sectional view of the vicinity of the color filter 25 in the figure. In this embodiment, for example, the red color filter 25R has a length L.
1, width L2, and a plurality of them are arranged at intervals L3, and are formed into a long belt shape as a whole. The remaining green and blue color filters 25G and 25B are also formed into a long band shape as a whole with the same dimensions and arrangement grooves as the color filter 25R. In this embodiment, segment electrodes 26a are formed in a band shape on the color filter 25R, and segment electrodes 26b are formed on the color filters 27R and 27B. Yuba et al.'s color filters 25R, 25G, 2
A light shielding layer 37 made of a metal such as chromium Cr or a synthetic resin material is formed between the portions 5B.

FIG. 5 shows a liquid crystal layer 29 in a color liquid crystal display device 21.
FIG. 6 is a perspective view illustrating the orientation direction of liquid crystal molecules of No. 33, and FIG. 6 is a diagram illustrating the orientation direction of the liquid crystal molecules. In this embodiment, the transparent substrate 24 has two liquid crystal layers. The orientation direction of the liquid crystal molecule 38b closest to b and the orientation direction of the liquid crystal molecule 38a closest to the transparent substrate 24a are twisted, for example, 90 degrees in the left rotation direction, as shown in FIG. 6(1). Ru. Furthermore, the liquid crystal molecules 39b closest to the transparent substrate 31b in the liquid crystal element 33 and the liquid crystal molecules 39a closest to the transparent substrate 31a are also twisted by 90 degrees in the left rotation direction, as shown in FIG. 6(1). 'be.

Furthermore, the liquid crystal molecules 38a, 39b in the liquid crystal element 22 are configured to be perpendicular to each other.
8b is twisted in the left rotation direction as shown in FIG. 6(2), and the liquid crystal molecules 39b and 39a in the liquid crystal element 23 are
The same effect can be achieved even when the liquid crystal molecules 38a and 39b are twisted in the dextrorotary direction and aligned parallel to each other as shown in FIG. 2. Also, liquid crystal molecules 38b, 38
a is twisted in the left rotation direction as shown in FIG. 6(3), liquid crystal molecules 39b and 39a are twisted in the right rotation direction as shown in FIG. 6(3), and liquid crystal molecules 38a and 39b are twisted in the right rotation direction as shown in FIG.
Even if the orientation directions are perpendicular to each other, the same effect can be achieved.

FIG. 7 is a block diagram showing an example of the configuration of the drive circuits 40 and 41, and FIG. 8 is a timing chart explaining the operation of this embodiment. The drive circuit 40 receives the common signal Sc shown in FIG. 8(2) from the control circuit 47 and the liquid crystal element 2.
A selection signal S1 for selecting whether to apply or stop the operating voltage is input to the terminal 3, the common signal Sc is supplied to the transparent electrode 42, and the selection signal S1 and the common signal Sc are connected to an exclusive OR circuit (hereinafter referred to as , EX circuit) 44, and its output is supplied as a segment (3S s ) to the transparent electrode 8i43.

On the other hand, as shown in FIG. 7(2), the common signal Sc and selection signals S2 and S3 for selecting the segment electrodes 26a and 26b, respectively, are input to the drive circuit 41. The common signal SC is supplied to the common electrode 28, and the selection signal S2 is supplied together with the common signal Sc EX times F!
@45, and its output is output as the segment signal Ss2 to the segment pole 26a. The selection signal S3 is also input to the EX circuit 46 together with the common signal Sc, and its output is supplied to the segment electrode 26b as a segment signal Ss3. Here, in Tables 3 to 5 below,
X circuit 44. ．． The truth table of 45.46 is shown.

Table 3 In Tables 3 to 5 above, symbols ■ to ■ refer to Figure 8 (3).
Corresponds to symbols ■～■ in. At this time, the liquid crystal element 23
The applied voltage is as shown in Figure 8 (4),
This applied voltage V becomes a driving voltage in the cases of symbols ■ and ■, and in the cases of symbols ■ and ■, it also indicates an operation stop state. In other words, in the case of symbol ■■, the liquid crystal element 23 is in a non-operating state, and corresponds to normally black. Table 6 shows the signal states in the liquid crystal element 22 in this case.

On the other hand, when the liquid crystal element 23 is turned on and normally white display is performed, the liquid crystal element 2 is driven by the drive circuit 41.
The states of the signals No. 2 are shown in Table 7 below.

The color display state in the configuration of the color liquid crystal display device 21 of this embodiment corresponds to the Example 1 column of Table 1 above. Here, in state 1 in Table 6, the segment electrodes 26a, 2
6b are both in the OFF state, and black is displayed as in column fil of Example 1 of Table 1 above. In state 2, the electrode 26a is in the ON state, the electrode 26b is in the OFF state, and red is displayed as shown in Table 1. In the 6th tabular suspension 3, electric f! 26a is a FF, and the electric fffi 26b is in an ON state, and as shown in Table 1, light blue, which is a mixture of green and blue, is displayed. In the sixth surface suspension 4; pole 26a
All of 26b are in the ○N state, and white is displayed as shown in Table 1.

In order to switch the liquid crystal element 23 from the normally black display state to the normally white display state, the selection signal S1 is switched at the timings shown by the symbols ■ and ■ in Table 2. Here, if red is displayed in the normally black state in state 2 of Table 6, in this embodiment, state 3 of Table 7 is realized in normally white display. That is, the selection signal S2 is inputted at the timings of symbols ■ and ■ in Table 4, and the selection signal S3 is inputted at the timings of symbols ■ and ■ in Table 5. As a result, state 3 in Table 6 is realized. At this time, the liquid crystal element 23 is in normally white display, and the fifth
Red is displayed as in state 2 of the table.

As described above, in this example, when the liquid crystal element 23 is switched from the normal black display state to the normally white display state, the background color is switched from black to white, and the display color remains red. Similarly, selection signals S2. A similar effect can be achieved by selecting the timing of S3. Moreover, such an effect can be similarly realized in the cases of Examples 2 and 3 in Table 1.

As described above, in this embodiment, when switching the display state between normally blank and normally white in the two-layer color liquid crystal display device 21, the background color is switched,
In addition, the display color can be kept the same, and display diversity can be greatly expanded.

Effects of the Invention As described above, according to the present invention, the display color of the area outside the display area of the first liquid crystal display element is changed to its complementary color by applying/cutting off the display signal to the second liquid crystal display element. Even in this case, the display color within the display area does not change, and only the background color can be switched. It is hoped that this will greatly expand the variety of displays.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a liquid crystal display device 21 according to an example of 81 embodiments of the present invention, FIG. 2 is a plan view of FIG. 1, and FIG. 3 is a liquid crystal display device 2
1, FIG. 4 is an enlarged sectional view of the vicinity of the color filter 25, FIG. 5 is a perspective view explaining the alignment state of liquid crystal molecules, and FIG. 6 is a diagram explaining the alignment state of liquid crystal molecules. ,
FIG. 7 is a block diagram explaining the configuration of the drive circuit 4041, FIG. 8 is a timing chart explaining the operation of this embodiment, and FIG. 9 is a sectional view of the conventional example. 21...Liquid crystal display device, 22.23..., liquid crystal element,
25... Color filter, 26... Segment electrode, 28... Common electrode, 29.33... Liquid crystal layer, 3
5゜36...Bolarizing plate, 28.29...Liquid crystal molecule, 4
0.41...Drive circuit, 44-46...EX circuit agent Patent attorney Number of strokes Keiichibe 5B 27a Fig. 4

Claims (1)

[Scope of Claims] A plurality of color selection members formed between a pair of light-transmitting substrates at least within a predetermined display area and each selecting one of a plurality of predetermined colors for transmitted light; A first liquid crystal display element having a transparent electrode and a liquid crystal layer interposed therebetween, and a second liquid crystal display element having a transparent electrode and a liquid crystal layer interposed between a pair of light-transmitting substrates over at least an area corresponding to the display area. a liquid crystal display element, a driving means for applying/cutting off a display signal to the second liquid crystal display element, and a color selected when applying/cutting off the display signal corresponding to the applying/cutting operation of the display signal by the driving means. and a second driving means for selecting a color selection member that achieves the same color as the color selected by the color selection member when the display signal is applied/interrupted when the display signal is cut off/applied to the selection member. A color liquid crystal display device featuring: