DE3415110A1 - REFLECTIVE MULTICOLOR LIQUID CRYSTAL DISPLAY - Google Patents

Description

April 19, 1984 ■ -: ':':.:. "D- 92Bi- - nrs

Dainippon Screen Seizo Kabushiki Kaisha

1-1 Tenjin-kitamachi, Teranouchi-agaru 4-come,

Horikawa-dori, Kamigyo-ku, Kyoto / Japan

Multi-color liquid crystal display working in reflection

The invention relates to a liquid crystal display device, and in particular to a multicolor liquid crystal display device reflection-type produced by a guest-host-type liquid crystal material Makes use.

Multicolor image display devices based on liquid crystal materials based, find commercial use in display units of computer terminals, television sets, Video monitors, etc. Regarding such multicolor image display devices Research and development work has been carried out on a large scale in recent years.

A manufacturing method for such a multicolor image display unit is disclosed in, for example, Japanese Patent Publication No. 58-10 2214, which is of the present invention Applicant has been submitted and is hereby incorporated by reference into the content of the present application.

It is now inevitable, however, behind a multicolor picture display device to provide a light source when the

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Display device is made as a transmission type display device by using two polarizer plates, In view of the fact that the great advantage of a liquid crystal display device lies in a low energy consumption, it is not preferable to use a light source in addition to be built in.

To determine the luminance-brightness or luminance-brightness of a To make the display device uniform, it is necessary to a diffuser plate e.g. B. upstream of frosted glass immediately behind the display device, so that the whole incident Light is well diffused.

In a reflection type display unit, the one tightly reflection plate arranged outside one of the polarizer plates contains, a multicolored image reproduction is achieved by means of thin color filter layers. The display characteristics strongly depends on the point of view. Such a display unit that works in reflection therefore has the disadvantage with the result that display picture elements are reduced in contrast at certain viewing angles.

Display devices or display devices operating in reflection reflective type, which do not require light sources, are advantageously used as black and white display devices used in desktop computers, clocks, etc. However, there are still no display devices known that are capable of are to reproduce the desired pattern in the desired colors.

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One might consider adding a color filter sheet to their pattern corresponds to an internal electrode arrangement of a liquid crystal display device, on the outer surface of a Form glass substrate from which the display device consists. The thickness of the glass substrate then hardly becomes be negligible, especially if the picture elements of the display device are fine, creating a parallax angle developed and accordingly a color difference depending on is generated by the respective position of the viewer. So it is impossible to get such good picture quality obtain.

In view of the above, it is an object of the invention to provide a multi-color liquid crystal display that operates in reflection to create the desired patterns and images can be reproduced without the need for a separate light source is.

According to the invention, this object is achieved by the features of claim 1. The invention provides a multicolor liquid crystal display device of the reflection type, which has:

a transparent or opaque first substrate; formed on one side of the first substrate, reflective electrodes;

color filter layers formed corresponding to predetermined portions of the reflective electrodes;
a transparent second substrate that of the first

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■ electrode is provided with a predetermined space opposite and carries transparent electrodes on one of its sides, which side faces the first substrate; and a polarizer plate;

_ being the first substrate, the reflective Electrodes, the color filter layers, the second substrate and the polarizer plate in each other overlay in the same order in which they are listed above, and

a liquid crystal material filled between the first and second substrates.

The color filter layers can be used alternatively or in combination

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on the surface of the reflective electrodes and / or

transparent electrodes may be provided.

The multi-color liquid crystal display device operating in reflection according to the present invention, neither a light source nor a special one requires that of the light source incoming light in a suitable way diffusing structure. It enables savings to be made in energy consumption and brings with it a simpler handling in their application.

Furthermore, the parallax angle can be minimized and an extremely good image quality can be achieved, since the color filter layers are arranged directly above the electrodes.

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Further objects, features and advantages of the present invention emerge from the following description of an exemplary embodiment with reference to the accompanying drawings. Show it:

1 shows a partial longitudinal section through a conventional multicolor liquid crystal display device reflection type in which a twisted nematic liquid crystal material Is used;

Figures 2a-2d

partial longitudinal sections through multicolor liquid crystal display devices reflection type according to the present invention, each comprising a guest-host type liquid crystal material (guest-host-type) is used; and

Figures 3a-3c

partial longitudinal sections through multicolor liquid crystal display devices of the reflection type according to the present invention, each exemplified using a small modification to that illustrated in FIG State of the art are produced.

Referring first to Fig. 1, there is a multicolor liquid crystal display device illustrates, in which a TN (twisted nematic) liquid crystal material is used.

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Since the display is of the reflection type or a display that works in reflection, the direction of view A and the direction of incidence B of the light are both on the same side of the device. In the example shown, a liquid crystal material 14 of the twisted nematic type (TN type) is hermetically filled between two glass substrate panels 12, 17. On the opposing surfaces of the glass substrates 12, 17 transparent electrodes 13, 15 with In ₃ O _3, among others, are formed in a comb-like shape such that the transparent electrodes 13 extend at right angles to the transparent electrodes 15 to form a single matrix unit to build.

In the case of the example shown in FIG. 1, color filter layers 16 of the colors R, ¹ ^ f and B are applied over the front surface of the transparent electrodes 15, which are located in the rear section of the display as seen in the direction of view A.

The layers superimposed on the outer surfaces of the glass substrates 12, 17 are polarizer plates 11, 18. The polarization axes of these polarizer plates 11, 18 are parallel to one another. The polarizer plates 11, 18 can but can also be arranged in such a way that their axes of polarization cross at right angles. In the latter case a negative image is obtained with respect to the image that is available in the former case.

The display device described above has the same structure

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such as transmission type multicolor liquid crystal devices. You can for example in accordance with the manufacturing process described in the above-mentioned Japanese Patent Publication No. 58-10 22 Ί4 is.

In the above example, one reflection plate 19 is whole provided on the rear of the body. The reflection plate 19 can be formed, for example, by using a film or the like having a film deposited or otherwise deposited thereon Metal such as Al, Cr, Ag or the like is attached to the outer surface of the polarizer plate 18, its reflective surface 19a being the liquid crystal material 14 faces.

Certain preferred embodiments of the present invention will now be described with reference to Figures 2a to 3c described.

2a to 2d show exemplary embodiments in which in each case a liquid crystal material of the guest-host type (guest-host type) Is used.

As an aside, what is used herein is "liquid crystal material of the guest-host type "meant a liquid crystal material in which a dichroic pigment of desired Color is mixed into the liquid crystal material and in which the orientation of the pigment coincides with the Changes the orientation of molecules of the liquid crystal material,

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if you apply an electric field to it.

As shown in each of FIGS. 2a to 2d, a liquid crystal 24 is hermetically filled between two glass substrate panels 22,27. On the opposing surfaces of the glass substrates 22, 27, transparent _{electrodes 23 consisting of In 3} O ₃ or the like and reflective electrodes 25 consisting of Al, Cr, Ag or the like are formed in each case. The electrodes 23, 25 are each designed in a comb-like shape, and they extend opposite one another at right angles to one another, forming a single matrix unit.

In the two embodiments shown in FIGS. 2a and 2b are color filter layers 26 ^ Ser colors R, G and B on the attached to the front surface of the reflective electrodes 25, which are located in the rear portion of the display. The foremost layer is a polarizer layer 21.

In the embodiment according to FIGS. 2a and 2b, it is not necessary for the glass substrate 27 to be transparent. It on the contrary, it is preferred that the glass substrate 27 can shield light so that outside light can pass through the back wall is prevented.

Also in the two exemplary embodiments shown in FIG. 2c and Fig. 2d, guest-host-type liquid crystal is used. The liquid crystal 24 is hermetically sealed between the two tabular glass plates

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22, 27 filled. Transparent electrodes 23 "and: reflective Electrodes 25 are formed on the opposing surfaces of the glass substrates 22, 27, respectively. Numeral 21 denotes a polarizer plate.

In the embodiments according to FIGS. 2c and 2d, the color filter layers are 26 are provided on the rear surfaces of the transparent electrodes 23.

In the case of the exemplary embodiments according to FIGS. 2c and 2d the transmission path of the light for reproducing images compared with the embodiments according to FIGS. 2a and 2b shorter by the layer thickness of the liquid crystal material, which is located between the transparent electrodes 2 3 and the reflective electrodes 25 is located. The embodiments according to FIGS. 2c and 2d therefore provide good image quality ready, and they have an even smaller parallax angle.

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Figures 3a to 3c illustrate multicolor liquid crystal display units reflection type made by practicing the present invention in various ways Way applies to the usual example of FIG.

In the conventional example shown in Fig. 1, the filter layers are color 16 and electrodes 15 are formed on the right side.

In Fig. 3a are similar to the embodiment according to

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Fig. -2b color filter layers 16 formed on the "right 3 <rite a; osye, as can be seen in the drawing, while suitable electrodes 13 for the selection of the color filter layers 16 on the are formed on the left side, as shown in the drawing. In Fig. 3b are similar to the embodiment according to Fig. 2 color filter layers 16 formed on the left side, as shown in the drawing, while for the selection of Color filter layers 16 serving electrodes 15 are formed on the right side as shown in this drawing. In Fig. 3c there are color filter layers 16 and electrodes 13 which are suitable for selecting the color filter layers 16, both formed on the left side, as can be seen in the drawing.

With "right side", especially in viewing direction A, the background (rear part) and with "left Side "should be the foreground of the display.

The above description of exemplary embodiments makes no reference to the specific manner in which the matrix electrodes are used be driven or controlled. As needs no further explanation, they can be done in different ways driven or controlled, for example in accordance with the time-divided control method (timedivided driving method), the control method based on a thin-film transistor, etc.

In the case of the driving method based on a thin film transistor there is in particular the possibility of

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watery glass substrate through the SOS substrate: (silicon ^ aiif substrate) of the thin film transistor and the reflective Electrodes by silicon chips per se.

The preferred exemplary embodiments of the invention shown in FIGS. 2b-d and 3a-c, in reflection Working multicolor liquid crystal displays can, seen in viewing direction A, in particular those summarized below Have shift sequence:

Fig. 2b: polarizer 21, glass substrate 22, transparent electrode 23, liquid crystal 24, color filter layer 26 in the transparent electrode 23 of corresponding geometry, reflective electrode 25, substrate 27. "

Fig. 2c: polarizer 21, glass substrate 22, transparent

Electrode 23, color filter layer 26 in the reflective Electrode 25 of corresponding geometry, liquid crystal 24, reflective electrode 25, substrate 27.

Fig. 2d: polarizer 21, glass substrate 22, transparent

Electrode 23, color filter layer 26 in the transparent Electrode 23 of corresponding geometry, liquid crystal 24, reflective electrode 25, substrate 27.

Fig. 3a: polarizer 11, glass substrate 12, first transparent Electrode 13, liquid crystal 14, color

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filter layer 16 in the -er & te'rv transparent Electrode 13 of corresponding geometry, second transparent electrode 15, glass substrate 17, Polarizer 18, reflector 19.

3b: polarizer 11, glass substrate 12, first transparent electrode 13, color filter layer 16 in the second transparent electrode 15 of corresponding geometry, liquid crystal 14, second transparent electrode 15, glass substrate 17, polarizer 18, reflector 19.

3c: polarizer 11, glass substrate 12, first transparent electrode 13, color filter layer 16 in the first transparent electrode 13 correspondingly Geometry, liquid crystal 14, second transparent electrode 15, glass substrate 17, polarizer 18, reflector 19.

For the rest, reference is made to the drawings that provide this list in case of doubt.

Having now fully described the invention, it will be apparent to one skilled in the art that many changes and modifications can be made without departing from the gist of the invention or its scope.

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Claims (3)

IS,; April 1984 Ü 929-7 - nrs Dainippon Screen Seizo Kabushiki Kaisha 1-1 Tenjin-kitamachi, Teranouchi-agaru 4-come, Horikawa-dori, Kamigyo-ku, Kyoto / Japan Reflective multicolor liquid crystal display Patent claims J, 1.Multicolor liquid crystal display device from reflection with a transparent or opaque first substrate; having reflective formed on one side of the first substrate Electrodes; each with predetermined sections of the reflective Electrodes correspondingly formed color filter layers; with a transparent second substrate that of the first Electrode is provided with a predetermined space opposite and on one of its sides transparent electrodes carries which side faces the first substrate; and with a polarizer plate; wherein the first substrate, the reflective electrodes, the color filter layers, the second substrate and the polarizer plate superimpose one another in the same order, EPO COPY 0W ■ - ^λ 3 4151 TO in which they are listed above; and with a liquid crystal material filled between the first and second substrates. 2. Multi-color liquid crystal display device of the reflection type according to claim 1, characterized in that the color filter layers are formed over the surfaces of their associated reflective electrodes. 3. The reflection type multicolor liquid crystal display device according to claim 1, characterized in that the color filter layers are formed over the surfaces of the transparent electrodes. EPO QQPY