KR840001583B1 - Liquid crystal display device - Google Patents

Abstract

A lquid crystal display device comprises a pair of electrodes indicating patterns, at least two liquid crystal layers interfolded on each other, and two polarizing plates having the same polarizing orientaion. The improvement is that another polarizing plate is inserted between two liquid crystal layers, whose orientation is different from those of the above two polarizing plates.

Description

Liquid crystal display device

1 is a plan view of a display portion of a conventional clock in which two liquid crystal layers are embedded.

FIG. 2 is an explanatory diagram of the arrangement of liquid crystal layers in the display unit shown in FIG.

FIG. 3A is an explanatory diagram of a light transmitting state in various regions of the display unit shown in FIGS. 1 and 2.

3B is a polarization direction display diagram of FIG. 3A.

FIG. 4A is an explanatory view of a light transmitting state in various regions of a liquid crystal device according to an embodiment of the present invention.

4B is a polarization direction display diagram of FIG. 4A.

FIG. 5A is an explanatory diagram of light transmitting states in various regions of a liquid crystal display, which is an embodiment in which three liquid crystal layers are embedded according to the present invention.

FIG. 5B is a polarization direction display diagram of FIG. 5A. FIG.

6 is a plan view of the clock display unit according to the present invention.

7 is a plan view of a watch with a display.

8 is a plan view of a wrist watch that is an application example of the present invention.

FIG. 9 is a perspective view of main parts of the watch shown in FIG. 8. FIG.

10 is a cross-sectional view of the main portion of FIG.

11 is a cross-sectional view of a wrist watch as another application of the present invention.

12 and 13 are plan views of a liquid crystal display device of a desktop electronic calculator as another application example of the present invention.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly, to a liquid crystal display device in which a white pattern appearing on a black pattern is completely removed or positively utilized by overlapping patterns appearing in each layer of a plurality of accumulated liquid crystal layers.

In one embodiment of the present invention, the white pattern is not displayed on the black pattern in the liquid crystal display device. Background Art In recent years, liquid crystal display devices have been widely used from displays in electronic devices such as watches, small clocks, and desktop electronic calculators. Furthermore, as shown in FIG. 1 of the accompanying drawings, the display portion 1 has an analog display portion 5 having an hour hand 2, a minute hand 3, and a second hand 4, and a digital display portion 6 indicating time by numbers. At the same time equipped with a wristwatch and a small watch have been developed. The analog display part 5 and the digital display part 6 of this display part 1 can be manufactured so that each may be formed as a liquid crystal layer as shown in FIG. More specifically, the upper and lower liquid crystal layers 7 and 8 have analog display patterns and digital display patterns, respectively. Polarizer plates 9 and 10 are arranged above and below the liquid crystal layers 7 and 8, and reflector plates 11 are arranged below the lower polarizer plate 10. The directions of the light transmission axes of the polarizer plates 9 and 10 are the same.

In the structure of the two liquid crystal layer, when the segments of the upper liquid crystal layer 7 and the segments of the lower liquid crystal layer 2 overlap each other and voltage is applied at the same time, the overlapping portion of the segments has a black pattern on the display panel. Make it visible above. For this reason, it is inevitable to make the display portion 1 so that the respective patterns in the liquid crystal layers 7 and 8 do not overlap each other, and therefore, it is impossible to provide a small electronic device.

Referring to FIGS. 3A and 3B, when a segment of upper and lower liquid crystal layers overlap each other and one voltage is applied at the same time, a white pattern is formed on a black pattern on the display panel of the overlapping portion, but is not visible. Let's do it.

FIG. 3A illustrates an arrangement state of a display unit in which a liquid crystal layer and a polarizer plate are embedded. The upper polarizer plate 12, glass plate 13, upper liquid crystal layer 14, glass plate 15, glass plate 16, lower liquid crystal layer 17, glass plate 18, lower polarizer plate 19, etc. These are arranged in the above order from top to bottom. The reference characters a, d, c, and b indicate the points passing by as they pass through this display. That is, light passes through the upper polarizer plate 12, the upper liquid crystal layer 14, the lower liquid crystal layer 17, and the lower polarizer plate 19 at points a, b, c, and d. In addition, reference numerals ①, ②, ③ are light paths of light traveling from top to bottom, and ① ′, ② ′, ③ ′, are light paths of light traveling from bottom to top (ie reflected from the reflector). On the optical paths ① and ① ', there are no electrodes for the liquid crystal layers 14 and 17, and on the optical paths ② and ②', one pair is placed on the glass plates 13 and 15 to seal the upper liquid crystal layer 14. Electrode 20 is provided. On the optical paths ③ and ③ ', the electrode 20 of the upper liquid crystal layer 14 and the electrode 20 of the lower liquid crystal layer overlap each other.

는 빛이 흡수되어 표시판에서 흑색무늬로 나타나는 것을 표시한다. 편광방향은 빛이 액정층 중의 전압이 인가된 부분을 지날때는 불변하며, 전압이 전혀 인가되지 않은 부분을 지날때는 90°만큼 변하게 된다. 따라서 상하단 액정층(14), (17)에 전혀 전압이 인가되지 않은 광행로 ①,①′상을 빛이 통과할 때는, 빛이 상단편광체판(12), 액정층(14), (17)하단 편광체판(19)을 지나게 되므로 표시판상에는 아무런 무늬가 나타나지 않는다. 그런데 상단 액전층(l4)에만 전압이 인가된 광행로 ②,②′상을 빛이 통과하게 되면, 광행로②의 방향으로 진행하는 빛은 하단 편광체판(19)을 통과하지 못하여 표시판상에서 흑색무늬로 나타나며, 광행로 ②′의 방향으로 진행하는 빛은 상단 편광체판(12)을 통과하지 못하여 표시판 상에서 역시 흑색무늬로 나타난다.3b shows the direction in which the light is biased immediately after passing through 12,14,17,19. In the figure, the symbols ↕, ↔ indicate the polarization direction,

Indicates that light is absorbed and appears as a black pattern on the display panel. The polarization direction is unchanged when the light passes the portion where the voltage is applied in the liquid crystal layer, and is changed by 90 ° when passing the part where the voltage is not applied at all. Therefore, when light passes through the optical paths ① and ① 'where no voltage is applied to the upper and lower liquid crystal layers 14 and 17 at all, the light passes through the upper polarizing plate 12, the liquid crystal layers 14, and 17. Since the lower polarizer plate 19 passes, no pattern appears on the display panel. However, when light passes through the optical paths ② and ② 'to which the voltage is applied only to the upper liquid crystal layer l4, the light traveling in the direction of the optical path ② does not pass through the lower polarizer plate 19 and the black pattern on the display panel. The light traveling in the direction of the optical path ② 'does not pass through the upper polarizer plate 12 and thus appears as a black pattern on the display panel.

When light passes through the optical paths ③ and ③ 'in which voltage is simultaneously applied to the liquid crystal layers 14 and 17 through a pair of electrodes respectively provided in the upper and lower liquid crystal layers 14 and 17, the light is 12 , 13, 14, 15, 16, 17, 18, 19, to form a pattern on the display panel.

In other words, the portion where the electrode pair 20 of the upper liquid crystal layer 14 and the electrode pair 20 of the lower liquid crystal layer 17 overlap each other is formed on the black pattern on the display panel when a voltage is applied to the electrodes at the same time. Let the white pattern appear.

Accordingly, the present invention provides a liquid crystal display device in which a plurality of accumulated liquid crystal layers express various kinds of patterns on the display panel, and the generation of black patterns on the black pattern due to the overlapping of the patterns is prevented to reduce the area of the display panel. One purpose.

In order to achieve the above object, the liquid crystal display device of the present invention includes a plurality of liquid crystal layers, and a plurality of polarizer plates are arranged on the uppermost liquid crystal layer, on the lowermost liquid crystal layer, and between adjacent liquid crystal layers. The polarizing plate plates adjacent to each other are arranged so that their light transmission axis directions are different.

On the other hand, in the liquid crystal display device of the present invention, the white pattern expressed on the black pattern by the overlapping of the segments of the liquid crystal layer is positively utilized as one display pattern.

However, in a general liquid crystal display device, when a voltage is applied through an electrode to form a predetermined pattern, the light transmitted through a portion of the liquid crystal layer to which the voltage is applied is different from the light incident on the boom in the deflection direction. It cannot pass through the polarizer plate. That is, the light transmitted through the portion of the liquid crystal layer corresponding to the predetermined pattern is expressed as a black pattern on the display panel. By such a method, it is difficult to obtain a pattern having colors, and the display panel not only has colors but also has a neat fashion. Furthermore, the design of the display device is rather limited. For example, in the case of the wristwatch shown in FIG. 7, the time portion 102 is located in the center of the front face 103 painted in black, and therefore, a white window must be provided in this center. Therefore, there is a restriction on the design of the display device of the colorful watch. Thus, in order to solve the above-mentioned difficulties and to obtain a colorful wrist watch, a portion of the front surface 103 except for the display part has been proposed to be colored. However, according to this suggestion, the colored portion is clearly displayed than the display portion, which makes it difficult to read the time displayed on the display portion. What's more, the light color on the front of the watch eliminates the neat look of the watch.

A display device intended to solve this problem has been disclosed in Japanese Patent Laid-Open No. 79-79663, which includes a dichroic dye in which each of the accumulated liquid crystal layers has a different color. Each pattern was expressed independently. That is, one lightly colored pattern is formed in one liquid crystal layer and another lightly colored pattern is formed in another liquid crystal layer so that a pattern having at least two colors can be expressed. However, in such a structure, a large number of expensive liquid crystal layer materials having different colors are required, which makes the display device expensive. Furthermore, when different colored patterns overlap each other, the color of the overlapping portion is changed through subtractive mixed color, which causes a problem such as an imbalance of colors. On the other hand, the present invention can be applied to a liquid crystal display device having a structure of a conventional liquid crystal display device that displays a white pattern on a black pattern or a corresponding color pattern, so that the price is low and neat. The liquid crystal display device as it is can be obtained.

In addition, the present invention is applied to provide an electronic device such as an electronic clock or a desktop electronic calculator in which the liquid crystal display device is decompressed.

As described above, in the liquid crystal display device to which the present invention is applied as an example, a plurality of liquid crystal layers each forming one pattern are accumulated and one pair of polarizer plates are arranged above and below the liquid crystal layer, and the liquid crystal layer is formed in the above liquid crystal layer. The desired patterns are formed by overlapping the patterns. The light becomes colored light passing through the liquid crystal layer from the bottom by a reflecting plate or a light source provided on the bottom of the liquid crystal layer, and thus a desired colored pattern is expressed. In addition, in the liquid crystal display device, at least one liquid crystal layer contains a dichroic dye representing a color therein, so that a predetermined pattern having a corresponding liquid is formed. Other features and advantages of the invention will appear from the following detailed description based on the accompanying drawings.

EXAMPLE

4A is an explanatory diagram of an arrangement of a liquid crystal display device (with two liquid crystal layers included) which is an embodiment of the present invention. FIG. 4B illustrates a deflection direction of light passing through the liquid crystal display of FIG. 4A. In FIG. 4A, the upper polarizing body plate 21, the glass plate 22, the upper liquid crystal layer 23, the glass plate 24, the intermediate polarizing plate 25, the glass plate 26, the lower liquid crystal layer 27, and the glass plate 28 are shown. ) And the lower polarizer plate 29 are arranged in the above order from top to bottom. The light travels from the top to the bottom of the display, and then is reflected by a reflector (not shown) to pass the display back from the bottom to the top.

Reference numerals ①, ②, ③, and ④ in the drawing also indicate light paths when light travels from top to bottom, and ① ', ②', ③ ', and ④' light paths when light is reflected and proceeds from bottom to top. .

On the optical paths ④ and ④ ', a pair of electrodes are provided with respect to the liquid crystal layers 23 and 27, respectively. A pair of electrodes are provided on the optical paths ③ and ③ ', and they are formed on the opposing surfaces of the glass plates 26 and 28 for sealing the lower liquid crystal layer 27. In the optical paths ② and ② ', a pair of electrodes 30 are formed on the opposite surface to the glass plates 22 and 24 which seal the upper liquid crystal layer 23.

There are no electrodes on the light path ①, ① '.

는 빛이 흡수되어 표시판상에 흑색무늬로서 나타난 것을 표시한다.The reference characters a, b, c, d, and e in the diagram also indicate the points passing by as light passes through the display. That is, light is emitted from the upper surface plate 21, the upper liquid crystal layer 23, the middle polarizer plate 25, the lower liquid crystal layer 27 and the lower polarizer plate 29 at points a, b, c, d, and e. Pass). On the other hand, symbols ↕ and ↔ indicate the deflected direction of the polarized light,

Indicates that light is absorbed to appear as a black pattern on the display panel.

In this structure, when a voltage is applied to the electrodes for the upper liquid crystal layer 23 and the electrodes for the lower liquid crystal layer 27 overlapping each other on the optical paths ④, ④ ', the overlapping portions of the electrodes are shown in FIG. 4B. Since the black pattern is formed on the display panel as shown in the bar, the white pattern that appeared on the black portion in the conventional display device can be removed. That is, since a voltage is applied to the upper liquid crystal layer 23, the light traveling through the optical path ④ is composed of the upper polarizer plate 21 and the upper liquid crystal part (the upper liquid crystal layer 23, the glass plates 22, and 24). While passing through, keep the deflection direction unchanged. Since the deflection direction of the intermediate polarizer plate 25 is different from the deflection direction of light incident thereon, the light transmitted through the upper liquid crystal part is absorbed by the intermediate polarizer plate 25 and the upper liquid crystal layer 23 to which a voltage is applied. The portion of the display panel corresponding to the area of) turns black. In addition, the light that traces the light path ④ 'is also maintained in the deflection direction while passing through the lower polarizer plate 29 and the lower liquid crystal part (consisting of the lower liquid crystal layer 27, the glass plates 26 and 28). Therefore, it is absorbed by the intermediate polarizer plate 25. Accordingly, a black pattern is formed on the display panel of the lower liquid crystal layer 27 to which the voltage is applied. Similarly, the overlapping portions of the regions where the voltage is applied at the same time in the upper and lower stage liquid crystal layers 23 and 27 also form a black pattern on the display panel.

When voltage is applied to only one of the liquid crystal layers 23 and 27 as shown in the light paths ②, ②'③ and ③ 'of FIG. 4A, the black pattern is the light paths ②, ②', of FIG. 4B. It is formed on the display panel as shown in 3) and 3 '. If no voltage is applied to the liquid crystal layers 23 and 27 as shown in the optical paths 1 and 1 in FIG. 4A, light passes through all of 21 to 29 and no pattern is displayed on the display panel. .

5A is an explanatory diagram of an arrangement state of a liquid crystal display device (with three liquid crystal layers embedded) which is another embodiment of the present invention. FIG. 5B illustrates a deflection direction of light passing through the liquid crystal display of FIG. 5A.

The same reference numerals in FIGS. 4a, b and 5a, b refer to the same parts. In FIG. 5A, reference numerals 31 and 33 denote glass plates, 32 denote liquid crystal layers, and 34 denote polarizer plates. The portion where two or more regions of the liquid crystal layers 23, 27, and 32 in which the same voltage is applied at the same time is overlapped as shown in the optical paths ③, ③ ', ④, ④' of FIG. 5B. Black patterns are formed on the display panel.

That is, the overlapping portion does not form a colorimetric pattern on the black pattern. Note that the polarizer plates 21 and 34 are different from each other in the transmissive axis direction, the polarizer plates 21 and 25 are the same, and the polarizer plates 29 and 34 also in the transmissive axis direction. They are different.

In the above description, an embodiment including two or three liquid crystal layers has been described. However, the present invention is not limited thereto, but may be applied to a liquid crystal display device including four or more liquid crystal layers. In this case, the polarizer plates should be provided above and below the uppermost liquid crystal layer and between adjacent liquid crystal layers, and the adjacent polarizer plates should be different from each other in the transmissive axis direction.

As described above, in the liquid crystal display device in which the plurality of liquid crystal layers are embedded in the present invention, a portion in which the pattern formed by each liquid crystal layer overlaps also forms one pattern. Therefore, the pattern by one liquid crystal layer and the pattern by another liquid crystal layer overlap as in the display portion of the clock shown in the drawing, and the area of the display portion can be reduced. That is, the electronic device can be miniaturized by having such a display portion. In addition, multiple patterns can be superimposed, resulting in a fresh pattern.

[Application Example]

FIG. 8 is a plan view of a wrist watch that is one application of the present invention, and FIG. 9 is a main perspective view of the wrist watch shown in FIG. FIG. 10 is a sectional view of main parts of FIG. 8 to 10, the liquid crystal layers 111 and 112 are accumulated from the top to the bottom in the wristwatch 110. The liquid crystal layer 111 is inserted and sealed between the pair of glass plates 113a and 113b, and the liquid crystal layer 112 is inserted and sealed between the pair of glass plates 114a and 1414b. The electrodes 115 are provided in the glass plates 113a and l13b at the portions corresponding to the patterns, and the electrodes 116 are provided in the glass plates 114a and 114b in the same manner. More specifically, the time display number 117 and the minute display number 118 and the like are formed using a well-known electrode segment (part of the electrode 115) at the center of the upper liquid crystal layer 11. In the circumferential portion of the liquid crystal layer 111, electrodes 115 representing 60 superdisplay points 119 are formed at equal intervals. In the lower liquid crystal layer 112, a pattern is formed by an electrode 116 covering all of the hour and minute display numbers 117, 118, and the display point 119, wherein the electrode 116 is the liquid crystal layer 112. It is installed all over the area.

The transmissive axes of the pair of light guide plates 120 and 121 which are respectively provided above and below the upper and lower liquid crystal layers 111 and 112 are parallel to each other and are disposed below the lower polarizer plate 121. The reflective surface of 122 is opposed to the polarizer plate 121. The reflecting surface of the reflecting plate 122 may be colored in a light color. The color of the reflecting surface becomes the display color of the time signal and the points 117, 118, and 119. For example, the central portion 122a of the reflecting plate 122 is green, and the circumferential portion 122b is red.

The following describes the display operation process of the liquid crystal display of the clock 11 shown in FIGS. 8, 9, and 10. When a voltage is simultaneously applied to each of the pattern forming regions of the liquid crystal layers 111 and 112, the portion where the pattern forming regions overlap, forms a white pattern on the black pattern as already described with reference to FIG. . Since the electrode 116 is installed in the entire region of the lower liquid crystal layer 112 in the clock 110, most of the display panel becomes black when a voltage is applied between the electrodes 115 and the electrodes 116. On the other hand, the upper and lower liquid crystal 111. The pattern forming regions of the (112) layer form a white pattern on a black pattern on the display panel with the time-digit numbers and the dots 117, 118, and 119.

In other words, 117, 118, and 119 are formed by the light reflected by the reflecting plate 112 and having the same color as the reflecting surface. Therefore, the time numbers 117 and 119 are green, and the time point 119 is red.

That is, in the clock, hours and minutes are expressed in green numbers on a black background, and seconds are expressed in red dots. At this time, voltage is continuously applied to the sixty pattern portions 119 in the circumference of the upper liquid crystal layer 111, which exhibits a red dot. This makes a colorful and refreshing watch.

Instead of the above manufacturing method, the glass plate without the electrode 116 is provided only in the region of the lower liquid crystal layer 112 corresponding to the time signals and the dots 117, 118, and 119. The surfaces of 114a and 114b may be painted with black paint. In this case, power consumption is reduced because the area of the electrode 116 is reduced. Moreover, when the indication of time is shown by the white pattern on a black background, you may leave the reflecting plate 112 colorless. FIG. 11 is a different application from that of the wristwatch shown in FIGS. 8 to 10. In this case, sufficient power can be used so that the light source 123 that emits colored light has a lower polarizer plate (instead of the reflecting plate 122). 121) is provided in the lower portion, to form a pattern showing a higher luminance than the clock shown in Figs.

12 is a plan view of a liquid crystal display device of a desktop electronic meter as another application example of the present invention. A segment 124 displaying a number in the same figure is formed in the upper liquid crystal layer 111A, and the segment 125 is formed in the lower liquid crystal layer 112A. Each segment 124 is slightly larger than the corresponding segment 125 and its formation is made to be the same. Since the overlapping portions of the segments 124 and 125 form a white pattern on the black pattern on the display panel, the shape of the number is expressed as if the white pattern is framed with black lines.

In the above application, if at least one of the liquid crystal layers 111A and 112A contains a dichroic dye representing a color therein, as disclosed in the above-mentioned Japanese Patent Application (Publication No. 79-79663) Since the liquid crystal layer containing the dye is colored when a voltage is applied thereon, the central portion of the segment forming the display character is colored. In addition, when the reflecting plate is colored in a suitable light color, a multicolor display device can be obtained by color matching of the display character and the reflecting plate. The liquid crystal layer containing a dichroic dye can also be used in the application examples of FIGS. 8 to 10 degrees.

As described above, according to the application example of the present invention, the overlapping portions of the pattern forming regions of the upper and lower liquid crystal layers are also expressed as one pattern. Forming method of the pattern is as follows.

In FIG. 13, the patterned segment 128 formed in the upper liquid crystal layer is slightly shifted in position in the segment of the lower liquid crystal layer. In this case, the display pattern is formed to have a smaller width by overlapping portions of the segments 128 and 129. That is, a shallow pattern is formed. In the conventional method, it is very difficult to obtain a thin pattern because the electrode having a small width cannot be easily manufactured.

However, according to the present invention, a thin pattern can be obtained very easily, and an effect other than the color effect can be obtained in view of the drawing.

The thin pattern can also be used to form the needle pattern of a liquid crystal clock with a moving needle. As described above, in the present invention, each of the pattern formation regions in the plurality of liquid crystal layers is superimposed and a desired pattern is formed. Therefore, the desired pattern appears in the form of a white pattern on the black pattern, which is obtained by the reverse effect of the conventional shortcomings and can be colored.

Meanwhile. Since the liquid crystal display device of the present invention is simple in structure and has a small number of parts to be used, not only the display device is inexpensive but also the manufacturing steps for completing the display device are reduced.

Claims (1)

A liquid crystal display sheet comprising a pair of electrodes for displaying a pattern and at least two liquid crystal layer waves stacked on each other and two polarizing plates having the same polarization direction, respectively, wherein another polarizing plate is formed between the two liquid crystal layers. A liquid crystal display device having a structure in which two polarizing plates are inserted in different polarization direction waves.

Images