JPH0497134A - Color liquid crystal display device - Google Patents

Abstract

PURPOSE:To improve the display quality by arranging a 3rd polarizing plate which has a polarizing direction orthogonal to a predetermined polarizing direction between a 1st and a 2nd liquid crystal element. CONSTITUTION:The color liquid crystal display device 7 is constituted by laminating a 1st polarizing plate 87, the 1st liquid crystal element 72, the 3rd polarizing plate 88, the 2nd liquid crystal element 73, and a 2nd polarizing plate 89 in this order. The polarizing direction of the 3rd polarizing plate 88 intersects the polarizing directions of the 1st and 2nd polarizing plates 87 and 89 perpendicularly. Last polarized light which is transmitted through the liquid crystal layer of the 1st liquid crystal element 72 which is applied with a voltage is cut off by the 3rd polarizing plate 88 and not made incident on the 2nd liquid crystal element 73. Consequently, a display color is prevented from becoming its complementary color even in an area where the formation area of a 1st display electrode 75 and the formation area of a 2nd display electrode 82 overlap with each other and the display quality 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 that displays predetermined characters, figures, etc. in color.

Prior Art FIG. 8 is a plan view of a conventional segment type liquid crystal display device 230. A plurality of segment electrodes 233 are arranged on the liquid crystal display device 230 to form the characters "1 day". Further, a color filter colored red, for example, is provided in the area A1, a green color filter is provided in the area A2, and a blue color filter is provided in the areas A3 to A5.

FIG. 9 is a cross-sectional view of the liquid crystal display device 230.

The liquid crystal layer 237 includes a transparent glass substrate 231a,
231b, and is sealed with a sealing resin 238. A plurality of segment poles 233 are formed on the surface of the glass substrate 231a on the liquid crystal layer 237 side, and an alignment film 234a is further formed on the surface.

On the other hand, a plurality of common electrodes 232 are formed on the surface of the glass substrate 231b on the liquid crystal layer 237 side, and an alignment film 234b is further formed on the surface. Glass substrate 23
On the surface of 1a, 231b opposite to the liquid crystal layer 237,
Polarizing plates 235a and 235b are provided, respectively.

The aforementioned red, green, and blue color filters 236 are formed on the polarizing plate 235a in a region including the segment electrodes 233 by a printing method or the like.

FIG. 10 is a sectional view showing another configuration of the liquid crystal display device 230. Here, in order to eliminate color shift due to parallax in the display area, the color filter 236 is formed on the common electrode 232 by an electrodeposition method, a printing method, or the like.

In such a liquid crystal display device 230, for example, a voltage is applied between the common electrode 232 and the electrode corresponding to the display area to be displayed among the segment electrodes 233 in the area A1. Light passes through the liquid crystal layer corresponding to the segment electrodes, and a red display can be performed. In other areas A2 to A5, green display and blue display can be performed using the same method.

Further, in the liquid crystal display device disclosed in USP-3840695, color filters are arranged on the front and rear surfaces of the liquid crystal display element, and only one color can be displayed in one unit area.

-Finally, since liquid crystal has wavelength dependence, the light-shielding property of the liquid crystal display device 230 is not perfect and cannot block light over the entire visible wavelength range. Therefore, in the liquid crystal display device 230 described above, when performing positive display (background color is white and display color is black), light passes through the liquid crystal layer 237 even when no voltage is applied to the liquid crystal layer 237. Since the area A1 in FIG. 8 mentioned above is colored red and appears to be distinguished from other areas, there is a problem that the display quality of the liquid crystal display device 230 deteriorates. Also, negative display (
If the background color is black and the display color is white), the liquid crystal layer 237
Since the light-shielding property of the color filter 236 is not perfect, the shape of the color filter 236 can be seen through even when no voltage is applied, resulting in a problem of deterioration of display quality.

In addition, the display color of the display area is determined by the color type of the color filter during manufacturing of the liquid crystal display device, so
It is not possible to display the same display area in different colors, resulting in poor display diversity and versatility.

In order to solve the above-mentioned problems, a liquid crystal display device using a fine band-shaped color filter was developed in Japanese Patent Laid-Open No. 60-26092.
1. Japanese Patent Publication No. 61-239220, Japanese Patent Application Publication No. 62-0919
It is disclosed in 17.

FIG. 11 is a cross-sectional view of a segment type color liquid crystal display device 301 using a band-shaped color filter. A color filter 305 is provided over almost the entire surface of the transparent glass substrate 304a by a method such as a printing method or a tIgi1 coloring method. A plurality of segment electrodes 306 are formed. color filter 30
5 is formed, for example, in a band shape in a direction parallel to the plane of FIG. 11, and a plurality of three types of filters, for example, red filters, green filters, and blue filters, are arranged in a predetermined order in a direction perpendicular to the plane of FIG. 11. ing. The segment electrode 306 includes the red filter, the green filter,
It consists of a red electrode, a green electrode, and a blue electrode, each corresponding to a blue filter.

A plurality of common electrodes 308 are formed on one surface of the light-transmitting glass substrate 304b over an area including the display area corresponding to the segment electrodes 306, and an alignment film 307b is further formed on the surface. Glass substrate 304
a, 304b are arranged such that the surfaces on which orientations M307a, 307b are formed face each other. The twisted nematic liquid crystal layer 309 is formed on a glass substrate 304a3.
04b and is sealed with a sealing resin 310. Furthermore, polarizing plates 311.
312 is provided.

Here, the polarizing plates 311 and 312 are arranged so as to form crossed nicols so that light does not pass through the liquid crystal layer 309 when no voltage is applied, thereby performing a so-called normally black display. By applying a voltage to a desired electrode among the three electrodes constituting the segment electrode 306, a desired color is displayed in the display area corresponding to the segment electrode 306. For example, if voltage is applied only to the red 1i electrode, red will be displayed in the display area, and if voltage is simultaneously applied to the red and green electrodes, yellow will be displayed due to the mixture of red and green light. Can be displayed.

Furthermore, white display can also be performed by simultaneously applying voltage to all the electrodes: the red electrode, the green electrode, and the blue electrode.

Problems to be Solved by the Invention The display image of the segment type color liquid crystal display device 230301 described above is determined by the shape of the segment poles 233, 306, and cannot be changed after the color liquid crystal display device 230, 301 is manufactured. It is inferior in terms of display diversity.

In order to improve display diversity, a color liquid crystal display device in which two liquid crystal elements for color display and a liquid crystal element for monochrome display are laminated has been proposed. FIG. 12 is a cross-sectional view of a two-layer liquid crystal display device 401.

The liquid crystal display device 401 has two display liquid crystal elements, a color display liquid crystal element 402 and a monochrome display liquid crystal element 403.

The color display liquid crystal element 402 includes a pair of transparent substrates 404
a, 404b, a plurality of segment electrodes 405 having translucency are formed on one surface of the transparent substrate 404a, and a transparent substrate 404a on which the segment electrodes 405 are formed.
A color filter 406 is formed on top. The color filter 406 is the same as the color filter 305 in FIG.
It has the same configuration as . On the surface of the color filter 406, orientation ) 11407a is formed.

A common electrode 1408 having translucency is formed on one surface of the transparent substrate 404b over at least a region including the segment electrode fi 405, and an alignment film 407b is further formed on the surface. Transparent substrates 404a, 404b
are arranged such that the surfaces on which the orientations M 407 a 407 b are formed face each other. liquid crystal layer 409
is interposed between transparent substrates 404a and 404b and sealed with a sealant 410.

The black and white display liquid crystal element 403 includes a pair of transparent substrates 411a.
, 411b, a plurality of segment electrodes 412 are formed on one surface of the transparent substrate 411a and have a plurality of light-transmitting segments 1 over a range corresponding to a predetermined shape to be displayed in the display area. An alignment film 413a is formed on the transparent substrate 411a on which the alignment film 412 is formed. On one surface of the transparent substrate 411b, a common ti 414 having translucency is formed over a region including at least the segment electrode 412, and on the transparent substrate 411b on which the common electrode 414 is formed, an alignment film 413b is formed. It is formed. The transparent substrates 411a and 411b have an alignment film 413a
, 413b are arranged such that the surfaces on which they are formed face each other.

The liquid crystal layer 415 is interposed between the transparent substrates 411a and 411b, and is sealed with a sealant 416.

Liquid crystal element 402 for color display and liquid crystal element 40 for black and white display
3, a transparent substrate 404a and a transparent substrate 411b are stacked so as to face each other. A polarizing plate 417 is arranged on the surface of the transparent substrate 404b opposite to the liquid crystal layer 409, and a polarizing plate 418 is arranged on the surface of the transparent substrate 411a opposite to the liquid crystal layer 415. These polarizing plates 417 and 418 are arranged in parallel Nicols.

The twist angles of the liquid crystal molecules in the liquid crystal layer 409 of the liquid crystal element 402 for color display and the liquid crystal layer 415 of the liquid crystal element 403 for black and white display are both 90'', and the liquid crystal molecules of the liquid crystal layer 409 are, for example, oriented levorototally. However, the liquid crystal molecules in the liquid crystal layer 415 are dextrorotated. That is, the helical directions of the liquid crystal molecules in the two liquid crystal elements 402 and 403 are set to be opposite to each other.
The orientation direction of the liquid crystal molecules closest to the transparent substrate 404a of the liquid crystal layer 415 and the orientation direction of the liquid crystal molecules closest to the transparent substrate 411b of the liquid crystal layer 415 are arranged to be orthogonal to each other.

FIG. 13 is a plan view of the liquid crystal display device 401. A 0 display area A6 is an area where poles 405 are formed as segments of the liquid crystal element 402 for color display, and color display is possible. The display area A7 is an area where the segment electrodes 412 of the liquid crystal element 403 for black and white display are formed, and black and white display is possible. Here, the polarizing plates 417 and 418 are arranged in parallel Nicols. Therefore, when no voltage is applied to the liquid crystal layer, incident light passes through the liquid crystal layer, thereby enabling so-called normally white display in which the background color is white.

Table 1 shows the driving states of the color display liquid crystal element 402 and the monochrome display liquid crystal element 40B in each display area of the liquid crystal display device 401, and the incident light on the color display liquid crystal element 402 and the monochrome display liquid crystal element 403. Also shown is the correspondence between the polarization direction of transmitted light and the colors displayed in the display area.

Here, it is assumed that the polarization directions of the polarizing plates 417 and 418 are parallel to the plane of FIG. 12, respectively.

(Margin below) Table 1 As shown in Table 1 above, if display area A6 displays red and display area A7 displays black, display area A
In display area A8 where 6 and display area A7 overlap, light blue (
There is a problem that a cyan color) is displayed.

An object of the present invention is to provide a color liquid crystal display device that solves the above technical problems and has significantly improved display quality.

Means for Solving the Problems The present invention provides a color liquid crystal display device in which first and second liquid crystal elements are laminated, each having a pair of transparent substrates sandwiching a liquid crystal layer therebetween, in which the first liquid crystal element has a transparent substrate. Provided over the entire surface of one side in the thickness direction of the optical substrate,
a plurality of color selection members each selecting one of a plurality of predetermined colors for transmitted light; and a plurality of color selection members provided within a predetermined first display area on the liquid crystal layer side of the translucent substrate to select one of the plurality of colors. a first display electrode formed for each selected member; the second liquid crystal element includes a second display electrode formed in a range corresponding to a predetermined second display area; a second liquid crystal of the first liquid crystal element; A first polarizing plate having a predetermined polarization direction is arranged on the opposite side of the element, and a second polarizing plate having the same polarization direction as the first polarizing plate is arranged on the opposite side of the second liquid crystal element from the first liquid crystal element. and a third polarizing plate having a polarization direction perpendicular to the predetermined polarization direction is disposed between the first and second liquid crystal elements.

Function In the color liquid crystal display device according to the present invention, the first (1i light plate, the first liquid crystal element, the third@light plate, the second liquid crystal element, and the second polarizing plate are laminated in this order. The polarization direction of the plate is perpendicular to the polarization direction of the first and second polarizing plates.Therefore, when no voltage is applied to the liquid crystal layer,
For example, the incident light that has passed through the first polarizing plate and has become linearly polarized light has its polarization direction rotated by, for example, 90 degrees by the first liquid crystal element, and is therefore transmitted through the third polarizing plate. Next, the polarization direction of this transmitted light is further rotated by 90 degrees by the second liquid crystal element, so that it is transmitted through the second polarizing plate.

In Uni, for example, the color selected by the color selection member is red,
By using green and blue, white color is displayed on the color liquid crystal display device by mixing red light, green light, and blue light.

Next, when a voltage is applied to the first display electrode of the first liquid crystal element, the incident light becomes linearly polarized light by the first polarizing plate, but since the liquid crystal layer to which the voltage is applied loses its optical rotation, it becomes linearly polarized light. is transmitted through the first liquid crystal element in the same polarized state. Here, since the polarization direction of the third light leaking plate is orthogonal to the polarization direction of the first polarizing plate, the transmitted light that has passed through the first liquid crystal element cannot pass through the third polarizing plate. By applying a voltage to the first display electrodes corresponding to the respective selected color selection members, green light and blue light are blocked, and red color is displayed on the color liquid crystal display device.

Next, when a voltage is applied to the second display electrode of the second liquid crystal element, the incident light passes through the first polarizing plate and becomes linearly polarized light, and the polarization direction is rotated by 90 degrees by the first liquid crystal element, so that the third polarizing plate Transparent. When a voltage is applied to the second liquid crystal element, the liquid crystal layer loses optical rotation, so that the transmitted light passes through the second liquid crystal element in the same polarized state. Therefore, the transmitted light that has passed through the second liquid crystal element cannot pass through the second @light plate, which has a polarization direction perpendicular to the polarization direction of the third polarizing plate, and therefore, in a color liquid crystal display device, it cannot be transmitted through the second @light plate, which corresponds to the second display electrode. The shape to be displayed is displayed in black.

In this way, in one color liquid crystal display device, color display and black and white display can be displayed individually or simultaneously, and display diversity is improved. Furthermore, by arranging the third polarizing plate between the first and second liquid crystal elements,
The immediately polarized light transmitted through the liquid crystal layer to which a voltage is applied in the first liquid crystal element is blocked by the third polarizing plate and does not enter the second liquid crystal element. Therefore, the first display t1il
Even in the area where the formation area of i and the formation area of the second display electrode overlap, the displayed colors are prevented from becoming complementary colors, and the display quality is improved.

Embodiment FIG. 1 is a sectional view of a color liquid crystal display device 71 which is an embodiment of the present invention, and FIG.
FIG. The color liquid crystal display device f7t has two twisted nematic mode liquid crystal elements: a color display liquid crystal element 72 and a monochrome display liquid crystal element 73.

The color liquid crystal display device 71 has a pair of transparent substrates 74a and 74b made of glass, plastic, etc., and a segment electrode 76 having translucency is provided on one surface of the transparent substrate 74a, corresponding to the area A11 shown in the second diagram. It is formed in the area where Transparent substrate 74 on which segment electrodes 8i76 are formed
A color filter 76 is provided over almost the entire surface of the substrate a, and an alignment film 77a is formed on the color filter 76.

A common electrode 78 having translucency is formed on one surface of the transparent substrate 74b over at least a region including the segment electrode 75, and an alignment film 77b is further formed thereon. The transparent substrates 74a and 74b are the alignment films 7
The twisted nematic liquid crystal layer 79 is arranged such that the surfaces on which 7a and 77b are formed face each other.

It is interposed between transparent substrates 74a and 74b and sealed with a sealant 80.

Polyimide resin was used for the alignment films 77a and 77b. The alignment films 74a and 74b are formed to have a layer thickness of, for example, 600 mm, and are made of woven nylon thread so that the alignment direction of the liquid crystal molecules is twisted by 90 degrees between the transparent substrates 74a and 74b, forming a levorotatory liquid crystal layer. Rubbed.

In order to keep the distance between the transparent substrates 74a and 74b constant,
A plastic spacer (not shown) is sandwiched between these substrates. With this spacer, the distance between the substrates is set to, for example, 5 μm. The sealing material 80 for sealing the liquid crystal layer 79 is, for example, epoxy resin. For the liquid crystal layer 79, a phenylcyclohexane mixed liquid crystal layer is selected, for example. Furthermore, cholesteric nonanoate is added to this liquid crystal layer to impart levorotatory properties.

The black-and-white display liquid crystal element 73 has a pair of transparent substrates 81a and 81b made of glass, plastic, etc., and one surface of the transparent substrate 81a has a translucent surface over an area corresponding to the display area A12 in FIG. A plurality of segment electric terminals having 8
An alignment film 83a is formed on the transparent substrate 81a on which the i82 and the segment electrodes 82 are formed.

On one surface of the transparent substrate 81b, a light-transmitting common electrode 84 is formed covering at least a region including the segment and the electrode 82, and a transparent substrate 81.b has a common electrode S4 formed thereon. An alignment film 83b is formed on the substrate 83b. The transparent substrates 81a and 81b are arranged such that the surfaces on which the alignment films 83a and 83b are formed, respectively, face each other. The twisted nematic liquid crystal layer 85 is formed on the transparent substrate 8
1a.

It is interposed between 81b and sealed by a sealing material 86.

Polyimide resin is used for the alignment films 83a and 83b,
A rubbing process is performed between the transparent substrates 81a and 81b so that the alignment direction of liquid crystal molecules is twisted by 90 degrees to form a levorotatory liquid crystal layer.

For the liquid crystal layer 85, for example, a phenylcyclohexane mixed liquid crystal was used. For example, cholesteric nonanoate is added to this liquid crystal layer as a levorotatory chiral substance. Transparent substrate 81a.

In order to keep the distance between the substrates 81b constant, a plastic spacer was sandwiched between these substrates, as in the case of the color display liquid crystal element 72, and the substrates were stacked one on top of the other.

The distance between the transparent substrates 81a and 81b is selected to be, for example, 5 μm.

Segment electrodes 75.82 and common electrode 7884 are formed of ITO (indium tin oxide). ITO
Generally, a medium resistance value of 20 to 50 ΩCm/mouth is used, but a low resistance value may also be used.

Liquid crystal element 72 for color display and liquid crystal element 7 for black and white display
No. 3 is arranged such that the transparent substrate 74a and the transparent substrate 81b face each other. A polarizing plate 87 is arranged on the side of the liquid crystal element 72 for color display opposite to the liquid crystal element 73 for black and white display, and a polarizing plate 89 is arranged on the side of the liquid crystal element 73 for black and white display opposite to the liquid crystal element 72 for color display. is placed. A polarizing plate 88 is arranged between the liquid crystal element 72 for color display and the liquid crystal element 73 for black and white display.

FIG. 3 is an enlarged plan view of the color filter 76, and FIG. 4 is an enlarged sectional view of the vicinity of the color filter 76. In the color liquid crystal display device 71, a color filter 76, which is a color selection member, is provided over almost the entire surface of a transparent substrate 74a. The color filter 76 is formed by arranging red, green, and blue filters in a matrix or mosaic pattern.

In FIGS. 3 and 4, the red filter is designated with the reference number R, the green filter is designated with the reference number G, and the blue filter is designated with the reference number B. The size of each filter JG, B is so small that it cannot be discerned with the naked eye.

- As an example, length L1 = 330 μm and width L2 = 80
.mu.m rectangular filters R, G, and B are used, and the spacing L3 between each filter is selected to be 30 .mu.m. therefore,
Three types of filters R, G lined up in the width direction C2 of the filter,
The area formed by B is 330 μm x 330 μm
is a square area.

The spacing L3 between the filters is determined by the manufacturing accuracy of color filters such as photoprocessing, and is generally 15 μm to 15 μm.
It is 40 μm.

In the arrangement of the filter, for example, an R-G-B permutation is repeated in the width direction C2 of the filter, and an R-B-G permutation is repeated in the length direction C1 of the filter. Filter R
, G, and B may be square or other shapes.

In addition, between each filter R, G, B, there is a black light shielding layer B.
L is formed. The light shielding layer BL is formed of chromium (Cr), black pigment, or the like.

FIG. 5 is an enlarged plan view of the segment pole 75. As mentioned above, on the transparent substrate 74a, a plurality of quadrilateral color filters R, G, and B of three colors red, green, and blue are arranged in a matrix or mosaic shape. This is a color liquid crystal display device 71 in which transparent electrodes as signal lines are arranged so as to sequentially connect segment electrodes corresponding to color filters.

The segment electrode 75 includes an electrode Sr for red color and tf for green color.
It consists of lsg and pole sb for blue color. Electric l1HSr,
Sg and Sb are formed in regions corresponding to filters R and CB, respectively, and serve as poles Sr and Sg, respectively.

sb is transparent electrode 91r, 91g as a signal line,
91b, respectively.

Using this connection method, red, yellow, green,
Seven colors, light blue (cyan), blue, white, and pink (magenta), can be displayed within a desired display stirrup area.

FIG. 6 shows a polarizing plate 87 in a color liquid crystal display bag 271.
, 88.89 and the alignment direction of liquid crystal molecules in a liquid crystal layer 79.85. Figure 6 (1
) indicates the absorption axis R1 of the polarizing plate 89. Figure 6 (
2) shows the alignment direction and twist direction of liquid crystal molecules in the liquid crystal layer 85 of the black and white display liquid crystal element 73. The alignment direction of the liquid crystal molecules closest to the transparent substrate 81a is indicated by an arrow R2, and this alignment direction R2 coincides with the absorption axis R of the eight polarizing plates.
It is orthogonal to 1. The alignment direction of the liquid crystal molecules closest to the transparent substrate 81b is indicated by an arrow R3, and therefore the liquid crystal molecules of the liquid crystal layer 85 are twisted 90 degrees to the left.

FIG. 6(3) shows the absorption axis R7 of the polarizing plate 88. FIG. 6(4) shows the orientation direction and twist direction of liquid crystal molecules in seven liquid crystal layers of the color display liquid crystal element 72. The alignment direction of the liquid crystal molecules closest to the transparent substrate 74b is indicated by an arrow R4, and the alignment direction of the liquid crystal molecules closest to the transparent substrate 74b is indicated by an arrow R5. Therefore, the liquid crystal molecules in the seven liquid crystal layers are twisted 90 degrees to the left. FIG. 6(5) shows an absorption axis R6 of the polarizing plate 87, and this absorption axis R6 is parallel to the alignment direction R5 of the liquid crystal molecules closest to the transparent substrate 74b.

As shown in FIG. 6, the twist angles of the liquid crystal molecules in the seven liquid crystal layers of the color display liquid crystal element 72 and the liquid crystal layer 85 of the monochrome display liquid crystal element 73 are both 90 degrees. Furthermore, the liquid crystal molecules in the liquid crystal layers 79 and 85 are both oriented levorototally. Further, the alignment direction of the liquid crystal molecules closest to the transparent substrate 74a of the seven liquid crystal layers and the alignment direction of the liquid crystal molecules closest to the transparent substrate 81b of the liquid crystal layer 85 are arranged to be perpendicular to each other. The i-source plates 87 and 89 are arranged so as to form parallel Nicols, and the polarizing plates 87 and 89 and the polarizing plates 88 are arranged so as to form orthogonal Nicols.

FIG. 7 is a diagram showing the electrical configuration of the color liquid crystal display device 71. As shown in FIG. A backlight 93 is arranged on the opposite side of the polarizing plate 87 from the color display liquid crystal element 72, and the light from the backlight 93 is transmitted/blocked using the color display liquid crystal element 72 and the monochrome display liquid crystal element 73. This allows the color liquid crystal display device 71 to perform color display and black and white display.

The color display liquid crystal element 72 is controlled by a color display liquid crystal element drive circuit 95. The color display liquid crystal element drive circuit 95 connects the common to the pole 78 via the signal line 121 based on the display control signal from the display control circuit 97.
A voltage is applied to the selected segment electrode 75 via the signal line group 122. This allows the color display liquid crystal element 72 to perform color display.

The black and white display liquid crystal element 73 is driven by a black and white display liquid crystal element drive circuit 96. The black and white display liquid crystal element drive circuit 96 applies a voltage to the common electrode 84 via the signal line 123 based on the srw signal from the display control circuit 97, and applies a voltage to the selected segment electrode via the signal line group 124. A voltage is applied to 82. As a result, black and white display can be performed on the black and white display liquid crystal element 73.

In the color liquid crystal display device 71 described above, the incident light from the backlight 93 passes through the polarizing plate 87 to become linearly polarized light, and the polarization direction is rotated by 90 degrees by the color display liquid crystal element 72, so that the polarized light is perpendicular to the polarizing plate 87. Since the zero-order light transmitted through the plate 88 is further rotated by 9° by the black-and-white display liquid crystal element 73, the linearly polarized light is transmitted through eight polarizing plates orthogonal to the polarizing plate 88. Therefore, the color liquid crystal display device 71 performs so-called normally white display. Normally white display means that when no voltage is applied to the liquid crystal layer, incident light passes through the liquid crystal layer, making the background color white, and changing the voltage of the liquid crystal layer in the area corresponding to the shape to be displayed. This is a display method in which a desired shape is displayed by blocking transmitted light by changing the alignment state of liquid crystal molecules by applying an electric current. Here, the color filter 76 is a fine rectangular filter RG, as shown in FIG.
The transmitted light becomes white light by mixing red light, green light, and blue light. That is, white is displayed as the background color on the color liquid crystal display device 71 when no voltage is applied.

The liquid crystal molecules in the seven liquid crystal layers to which a voltage is applied are aligned in the direction of the electric field. Therefore, the linearly polarized light that has passed through the polarizing plate 87 passes through the liquid crystal layer 79 in an almost unchanged polarized state.

Here, since the polarizing direction of the polarizing plate 88 is orthogonal to the polarizing direction of the polarizing plate 87, the linearly polarized light that has passed through the liquid crystal layer 79 cannot pass through the polarizing plate 88.

The seven liquid crystal layers have voltage applied (ON)/non-applied (OFF)
Table 2 below shows the correspondence between the 0N10FF state of the segment electrode 75, the function of the seven liquid crystal layers as a light shutter, and the display color displayed in the display area. ing.

In Table 2, "O" indicates the oven state of the optical shutter, and "." indicates the closed state of the optical shutter.

(Margin below) Table 2 Table 3 below shows the driving states of the liquid crystal element 72 for color display and the liquid crystal element 73 for black and white display in each display area of the color liquid crystal display device 71, and the liquid crystal element 7 for color display.
2 and the polarization directions of incident light and transmitted light to the black-and-white display liquid crystal element 73 and the colors displayed in each display area are shown. Here, it is assumed that the polarizing direction of the polarizing plates 87 and 89 is parallel to the plane of the first drawing, and the polarizing direction of the polarizing plate 88 is perpendicular to the plane of the first drawing.

As shown in Table 3 above, black is displayed in the display area A1B where the color display and monochrome display overlap. Therefore, unlike in the past, the complementary color of the display color of the color display is not displayed in the area where the black and white display and the color display overlap (the first
Refer to table q), independence of display between color display and monochrome display is ensured, and display images can be recognized. This significantly improves the display quality of the color liquid crystal display device 71.

As another example, in the liquid crystal layer 79, 88, the alignment directions of the nearest liquid crystal molecules may be parallel and the twist directions may be opposite, or the alignment directions of the nearest liquid crystal molecules may be orthogonal. However, the twist direction may be opposite.

Effects of the Invention As described above, according to the present invention, color display and monochrome display can be performed by individually driving the first and second liquid crystal elements.

At this time, even if the color display image and the monochrome display image overlap, the overlapping area is prevented from becoming a complementary color to the color of the color display image, as in the past, and the independence of the color display and monochrome display is improved. Secured. This significantly improves the display quality of the color liquid crystal display device.

[Brief explanation of drawings]

FIG. 1 shows a color liquid crystal display device 7 which is an embodiment of the present invention.
1, FIG. 2 is a plan view of the color liquid crystal display device 71, FIG. 3 is an enlarged plan view of the color filter 76, FIG. 4 is an enlarged sectional view of the color filter 76, and FIG. 5 is a plan view of the segment electrode 75. Enlarged plan view, FIG. 6 shows color liquid crystal display device 7
A diagram showing the correspondence relationship between the polarization direction of the polarizing plates 87, 88, 89 and the orientation direction of the liquid crystal molecules of the liquid crystal layer 7985 in 1.
FIG. 7 is a block diagram showing the electrical configuration of a color liquid crystal display device 71, FIG. 8 is a plan view of a conventional liquid crystal display device 23,
9 and 10 are cross-sectional views of a conventional liquid crystal display device 230, FIG. 11 is a cross-sectional view of a conventional color liquid crystal display device 301, FIG. 12 is a cross-sectional view of a conventional two-layer liquid crystal display device 401, and FIG. The figure is a plan view of a color liquid crystal display device 401. 7. Liquid crystal display device, 72... Liquid crystal element for color display, 73... Liquid crystal element for black and white display, 74a. 74b, 81a, 81b = transparent substrate, 75.82 segments lt%, 76 ・Color filter, 7884...
・Common electrode, 79.85...Liquid crystal layer, 8788.89
-[Original plate, 95...Liquid crystal element drive circuit for color display, 9
6...Liquid crystal element drive circuit for black and white display, 97...Display control circuit Agent Patent attorney Number of strokes Keiichi Figure 10

Claims (1)

[Claims] In a color liquid crystal display device in which first and second liquid crystal elements are stacked, each having a pair of transparent substrates sandwiching a liquid crystal layer therebetween, the thickness of the first liquid crystal element is determined by the thickness of the transparent substrate. Provided over the entire surface on one side of the direction,
a plurality of color selection members each selecting one of a plurality of predetermined colors for transmitted light; and a plurality of color selection members provided within a predetermined first display area on the liquid crystal layer side of the translucent substrate to select one of the plurality of colors. a first display electrode formed for each selected member; the second liquid crystal element includes a second display electrode formed in a range corresponding to a predetermined second display area; a second liquid crystal of the first liquid crystal element; A first polarizing plate having a predetermined polarization direction is arranged on the opposite side of the element, and a second polarizing plate having the same polarization direction as the first polarizing plate is arranged on the opposite side of the second liquid crystal element from the first liquid crystal element. A color liquid crystal display device, further comprising: a third polarizing plate having a polarization direction orthogonal to the predetermined polarization direction, disposed between the first and second liquid crystal elements.