WO1996003672A1

WO1996003672A1 - Liquid crystal display device equipped with input function and electronic appliance using the same

Info

Publication number: WO1996003672A1
Application number: PCT/JP1995/001462
Authority: WO
Inventors: Hiroshi Wada
Original assignee: Seiko Epson Corporation
Priority date: 1994-07-21
Filing date: 1995-07-21
Publication date: 1996-02-08
Also published as: JP3613800B2

Abstract

A reflection type or semi-transparent reflection type liquid crystal device wherein an input panel having a pair of input electrodes spaced with a predetermined gap is integrated with an FSTN type liquid crystal cell. The liquid crystal display device comprises first and second polarizing plates that sandwich the input panel and the liquid crystal cell, and a phase difference plate consisting of an optically anisotropic polymer film is brought into close contact with the surface of the liquid crystal cell. Since the first polarizing plate reduces the quantity of light incident into the input panel, the quantity of light reflected at the boundary between the input panel and the air layer or reflected from the liquid crystal cell surface decreases. Further, because an air layer does not exist between the liquid crystal cell and the phase difference plate, coloration by reflected light passing through only one of them can be prevented, and black-and-white display having high contrast can be accomplished.

Description

Akira Itoda Liquid crystal display device with input function and electronic equipment using the same

The present invention relates to a reflective or transflective liquid crystal display device in which a so-called sunset panel is integrated with a liquid crystal cell, and an electronic device incorporating the liquid crystal display device. Background art

2. Description of the Related Art Conventionally, low power consumption and low voltage driven liquid crystal display elements have been widely used as display means in small portable information terminal devices such as mobile phones, electronic organizers, and palmtop computers. In recent years, in order to further reduce the size, an input mechanism called the evening panel is superimposed on the liquid crystal panel and integrated, with an input function that can press this or input data using a stylus pen. Liquid crystal display elements are used. Since a liquid crystal display device having such a touch panel has a reduced light transmittance as a whole and a dark display surface, for example, as disclosed in Japanese Patent Application Laid-Open No. 61-2798926, The lower transparent electrode group and the upper transparent electrode group that constitute the input matrix are disposed on the upper surface of the liquid crystal display and the rear surface of the upper polarizing plate facing the lower electrode, respectively, to reduce the overall thickness of the device. And the display is brighter and easier to see. In the input device disclosed in Japanese Patent Application Laid-Open No. 63-086332, a coordinate detector as input means is disposed between two upper and lower polarizing plates of a liquid crystal display. The protective film of the coordinate detector has been omitted to improve light transmission and reduce the overall thickness.

Super twisted-donematic (STN) liquid crystal with large display capacity In the display element, a two-layer STN (DS TN) system in which a color tone compensating liquid crystal cell is superimposed on a display liquid crystal cell and arranged between two polarizing plates, or, for example, Japanese Patent Publication No. 3-50249 As described in, the film compensation type S TN (FS TN) method using an optically anisotropic polymer film as the retarder optically compensates for the coloring caused by the birefringence effect of the incident polarized light. , Black and white display is possible. In the case of the DSTN type liquid crystal display device, the light transmittance is further reduced by overlapping the touch panel, and the display screen becomes smaller, for example, as described in JP-A-3-11514. As described above, an input electrode is formed on each of the opposing surfaces of a pair of transparent substrates constituting the color tone compensating liquid crystal cell, and the light transmittance is increased by also using the sunset panel. Also, in the case of the FSTN type, as disclosed in Japanese Patent Application Laid-Open No. 3-121523, a touch panel is sandwiched between a liquid crystal cell and its display-side polarizing plate, and A technology has been proposed in which a transparent substrate on the polarizing plate side is formed of a retardation plate made of a uniaxially stretched high molecular film to improve the contrast ratio and obtain a monochrome display.

In addition, the input display device disclosed in Japanese Patent Application Laid-Open No. 63-234315 includes an upper electrode substrate of a liquid crystal display device by omitting one substrate of the touch panel, and an upper polarizing plate. By omitting the function and adding the function to the electrode insulating layer provided between the opposing electrode substrates of the sunset panel, the overall device is made thinner and the contrast is improved.

In general, in a liquid crystal display device, it is known that the condition of ambient light affects the contrast ratio. If the reflected light on the display surface is strong, the visibility is impaired. The contrast of the liquid crystal display device having the evening switch panel is significantly reduced due to reflection, compared to the liquid crystal display device not having the evening switch panel. In particular, in the case of a reflective liquid crystal display element, if there is an air layer in the structure, light reflected from the surface of a glass substrate, a film, or the like in contact with the air layer can be ignored. /

-3-There is a problem that the display becomes hard to see, and the contrast ratio drops significantly, making the display difficult to see.

FIG. 3 shows a configuration of a general FSTN-type liquid crystal display device having a conventional input function. A liquid crystal cell 1 is sandwiched between a pair of upper and lower transparent electrode substrates 5 and 6 having transparent electrodes 3 and 4 formed on opposing surfaces of the liquid crystal cell 1 with a spacer 2 interposed therebetween. Polarizing plates 8 and 9 are arranged outside of 5 and 6, respectively, and a retardation plate 10 made of an optically anisotropic polymer film is provided between the upper polarizing plate 8 and the upper electrode substrate 5, Reflecting plates 11 are provided on the lower surface of the lower polarizing plate 9, respectively. The input panel 12 has a pair of upper and lower transparent substrates 16 and 17 formed on opposite surfaces of a pair of upper and lower transparent substrates 14 and 15 which are separated from each other by a small distance via a spacer 13. When 4 is pressed, the upper and lower transparent electrodes are connected to each other. In general, it is preferable that the upper polarizer 8 of the liquid crystal cell 1 and the lower substrate 15 of the input panel 12 are closely adhered to each other with an adhesive or the like. They are separated by a gap that does not cause tonning.

In the case of such a reflective liquid crystal display device, ambient light is transmitted through the input panel 12 and the liquid crystal cell 1 while passing through the surface of the transparent substrate 14 and the interface between the transparent substrate 14 and the transparent electrode 16. , Surface of transparent electrode 16, Surface of transparent electrode 17, Interface between transparent electrode 17 and transparent substrate 15, Surface of transparent substrate 15, Surface of upper polarizer 8, Upper polarizer 8 and retarder 10; interface between retarder 10 and transparent substrate 5; interface between transparent substrate 5 and transparent electrode 3; interface between transparent electrode 3 and liquid crystal layer 7; interface between liquid crystal layer 7 and transparent electrode 4 At the interface between the transparent electrode 4 and the transparent substrate 6, and at the interface between the transparent substrate 6 and the lower polarizing plate 9. The reflected light is generated regardless of the presence or absence of the display light, and is superimposed on the display light modulated according to the display information. Therefore, even if the amount of display light does not change, if the amount of reflected light increases, the contrast ratio will decrease. Above all, the surface of the transparent substrate 14, the surface of the transparent electrode 16, the surface of the transparent electrode 17, the surface of the transparent substrate 15, and the surface of the upper polarizer 8 are usually in contact with the air layer and the refraction thereof. The reflected light is relatively strong due to the large difference in the rates. Therefore, in the case of the conventional liquid crystal display device with an input function as shown in FIG. 3, the reflected light is attenuated by the upper polarizer 8 to a light amount of substantially 50% or less of the incident light amount. Since the light before reflection is reflected, there is a problem that the contrast ratio is greatly reduced and the visibility of the display is deteriorated.

When an air layer exists between the upper electrode substrate 5 of the liquid crystal cell 1 and the retardation plate 10, light reflected on the liquid crystal cell surface in contact with the air layer passes through the retardation plate 10. However, the reflected light is colored because it does not pass through the liquid crystal cell. Therefore, in the above-described liquid crystal display device having the conventional structure, there is a problem that the display is not an original black and white display. Also, when the retardation plate 10 is disposed between the lower electrode substrate 6 of the liquid crystal cell and the lower polarizer 9, the lower electrode substrate of the liquid crystal cell and the retardation plate When an air layer exists, the light reflected on the surface of the phase difference plate in contact with the air layer passes through the liquid crystal cell but does not pass through the phase difference plate, and thus the same problem occurs.

In order to solve such a problem of surface reflection, a handwriting input tablet disclosed in Japanese Patent Application Laid-Open No. Hei 5-173707 discloses a protective hard coating having a high light reflectance on the upper surface of a transparent sunset panel. The display side polarizer of the liquid crystal display element is placed on the upper surface of the transparent touch panel instead, and the surface is nonglare treated to suppress the decrease in visibility due to the reflection of external light. The trust ratio is kept high. In addition, the evening panel disclosed in FIG. 1 of Japanese Patent Application Laid-Open No. 5-122882 is provided with a retardation plate (square plate), a polarizing plate, and a touch panel disposed in front of a liquid crystal cell. A non-glare-treated transparent film is laminated, and the amount of light reflected from the surface of the liquid crystal cell is reduced by the action of the retardation plate and the polarizing plate. Last and display accuracy are improved. In this case, in order to reduce the amount of light reflected from the liquid crystal cell surface, the angle between the polarization axis of the polarizing plate and the slow axis of the phase difference plate needs to be 45 degrees. The reason is that when linear light that has passed through the polarizing plate passes through the λ Ζ 4 plate, it becomes either left-handed or right-handed circularly polarized light, but the reflected light is circularly polarized light that is opposite to the incident circularly polarized light. After passing through the 板 Ζ 4 plate again, it becomes linearly polarized light whose vibration direction differs by 90 degrees from that at the time of incidence, and that light is absorbed by the first polarizing plate and does not exit to the outside, but is reflected light It is because it is not seen in the eyes.

However, when an FS 表示 -type liquid crystal cell having a structure including a polarizing plate, a retardation plate, a liquid crystal cell, and a polarizing plate is used for the liquid crystal display device shown in FIG. When the polarized light passes through the polarizing plate, the quantity of light becomes 1Ζ2, which causes a problem that the display becomes dark. Therefore, an object of the present invention is to reduce the influence of surface reflection due to an input panel, a liquid crystal cell, and the like when an input panel is integrated with an FSTΝ type liquid crystal cell in view of the above-described problems of the related art. An object of the present invention is to provide a high-performance liquid crystal display device with an input function that can obtain a sufficient contrast, thereby making the display easier to see, and enabling better black-and-white display. Another object of the present invention is to realize a good black-and-white display with a high contrast ratio in an electronic device equipped with a liquid crystal display device with an input function as a display means, thereby increasing the display capacity and improving the performance. It is to plan. Disclosure of the invention

In order to achieve the above object, according to the present invention, a liquid crystal cell sandwiching a liquid crystal between a pair of opposed electrode substrates, and a display surface side of the liquid crystal cell and an opposite side thereof are provided. A first and a second polarizer, a retardation plate closely contacted with the surface of the liquid crystal cell, and a reflector disposed outside the second polarizer. An input panel having a pair of input electrodes separated at a constant interval, wherein the input panel is disposed between the first polarizing plate and the liquid crystal cell. A display element is provided. By arranging the first polarizer in front of the input panel, light passing through the input panel is reduced, so that the presence of an air layer formed by the input panel or between the input panel and the liquid crystal cell causes the liquid crystal Since the amount of light reflected by the cell surface decreases, a high contrast display can be obtained. Furthermore, since the liquid crystal cell and the retardation plate are in close contact with each other, reflected light passing through only one of them can be substantially eliminated, so that coloring due to the reflected light can be effectively prevented, and good black and white can be obtained. Display can be realized.

The input panel is of a so-called Utsuchi panel type in which input electrodes are provided on opposing surfaces of a pair of input electrode substrates separated at a fixed interval, and input electrodes are provided on both surfaces of a transparent electrode substrate. Each type can be used to form coordinates and determine coordinates by contact with a stylus pen or the like. In the case of the evening panel type, an air layer is formed between the input electrode substrates. However, according to the present invention, the amount of light reflected from the inside of the input panel is reduced due to the presence of the air layer. Good display of contrast can be obtained.

It is convenient to dispose the retardation plate on the display surface side of the liquid crystal cell. In this case, since the amount of light reflected after passing through the phase difference plate without passing through the liquid crystal cell is small, coloring by the phase difference plate can be prevented.

Further, the phase difference plate can be arranged between the liquid crystal cell and the lower polarizing plate. In this case, coloring due to reflected light passing only through the liquid crystal cell can be prevented.

In one embodiment, the liquid crystal display has a range of 180 degrees to 360 degrees. It is a so-called FSTN type using a nematic liquid crystal twisted and aligned. Also, a semi-transmissive reflector may be used, and a light source may be provided on the back side to form a transflective type.

As the retardation plate, an optically anisotropic polymer film can be used, and it is convenient that the polymer film is subjected to uniaxial stretching. For such an optically anisotropic film, polycarbonate, polysulfone, polyvinyl alcohol, polyethersulfone, polyarylate, polyolefin or polymethyl methacrylate is used. In addition, a twisted liquid crystal polymer film can be used for the retardation plate.

The input panel advantageously has a retardation value of 50 nm or less. In the present invention, since the polarizing plate is disposed outside the input panel, coloring is effectively suppressed by reducing the retardation.

Further, if the surface of the first polarizing plate is subjected to non-glare treatment, specular reflection on the surface can be reduced, which is advantageous.

Further, according to the present invention, there is provided an electronic apparatus equipped with the above-described liquid crystal display device with an input function as a display means. BRIEF DESCRIPTION OF THE FIGURES

Hereinafter, the present invention will be described in detail using preferred embodiments with reference to the accompanying drawings.

FIG. 1 is a sectional view showing a preferred embodiment of a liquid crystal display device with an input function according to the present invention.

FIG. 2 is an explanatory diagram showing the orientation direction of liquid crystal molecules, the direction of the slow axis of the retardation plate, and the direction of the polarization axis of the polarizing plate in the embodiment shown in FIG.

FIG. 3 is a cross-sectional view showing the structure of a conventional liquid crystal display device with an input function. BEST MODE FOR CARRYING OUT THE INVENTION

FIG. 1 schematically shows the configuration of a preferred embodiment of a liquid crystal display device with an input function according to the present invention. The liquid crystal cell 21 of this embodiment, which is a reflection type of the FSTN system, includes a pair of upper and lower transparent electrode substrates 23 and 24 opposed to each other through a spacer 22. For example, upper and lower transparent electrodes 25 and 26 made of, for example, an ITO film are formed, and between the electrode substrates is 180 ° to 360 °. The liquid crystal 27 is filled with the twisted oriented nematic liquid crystal 27 in the range. On the upper surface of the upper transparent electrode substrate 23, a retardation plate 28 made of an optically anisotropic polymer film is closely adhered via an adhesive layer such as an adhesive. On the lower surface of the lower transparent electrode substrate 24, a lower polarizing plate 29 and a reflecting plate 30 are similarly adhered via an adhesive layer. For the retardation plate 28, for example, a uniaxially stretched film such as polycarbonate, polysulfone, polyvinyl alcohol, polyethersulfone, polyarylate, polyolefin, or polymethylmethacrylate is used. Alternatively, a twisted liquid crystal polymer film is used.

The input panel 31 constituting the input mechanism of the present embodiment is disposed so as to face each other via a pair of upper and lower transparent electrode substrates 32, 33 Similarly, upper and lower transparent electrodes 35 and 36 made of an ITO film or the like are formed on the respective opposing surfaces. On the upper surface of the upper electrode substrate 32, an upper polarizing plate 37 is adhered via an adhesive layer. The upper and lower electrodes 35, 36 are normally separated by a certain gap 38 so that they do not come into contact with each other, but when the upper electrode substrate 32 is pressed from above the upper polarizing plate 37, the upper and lower electrodes 35, 36 are electrically connected to each other. Connected. The upper electrode substrate 32 includes polycarbonate, polysulfone, polyvinyl alcohol, polyether sulfone, polyarylate, polyolefin, and polymethylmethacrylate. -Glass and glass are used.

FIG. 2 shows the alignment direction of the liquid crystal molecules, the slow axis direction of the retardation plate 28, and the polarization axis directions of the upper and lower polarizing plates 37, 29 in the liquid crystal display device of the present embodiment shown in FIG. Is shown. In the figure, the angles α and β 7 correspond to the direction 4 of the slow axis of the retardation plate 28 with respect to the alignment direction 41 of the liquid crystal molecules in contact with the inner surface of the lower electrode substrate 24 of the liquid crystal cell 21, respectively. 2, the angle formed by the polarization axis direction 43 of the upper polarizing plate 37, and the angle formed by the polarization axis direction 44 of the lower polarizing plate 29. The angle 0 is twisted between the alignment direction 45 of the liquid crystal molecules in contact with the inner surface of the upper electrode substrate 23 of the liquid crystal cell 21 and the alignment direction 41 of the liquid crystal molecules in contact with the inner surface of the lower electrode substrate 24. Is the twist angle of the liquid crystal 27. Note that each of the angles was positive in a counterclockwise direction. This torsion angle 0 is 180 ° to 360 ° described above. By stabilizing at an angle within the range, a good contrast can be obtained.

According to the present embodiment, with the above-described configuration, the amount of light incident on the input panel 31 is reduced according to the light transmittance of the upper polarizing plate 37 disposed thereon. Reflection by the surface of the input panel or liquid crystal cell is reduced. On the other hand, since the amount of light passing through the liquid crystal cell 21 is almost the same as that of the related art, the light emitted from the upper polarizing plate 37 is reduced by the amount of reflected light that is smaller than that of the related art. Since the contrast ratio is greatly improved, the display becomes easier to see.

In addition, since the phase difference plate 28 is brought into close contact with the surface of the upper electrode substrate of the liquid crystal cell 21, no air layer is formed between them, so that the phase difference plate 28 does not pass through the liquid crystal cell after passing through the phase difference plate. The amount of light reflected is small. Therefore, according to the liquid crystal display device of the present invention, the reflected light can be effectively prevented from being colored by the retardation plate, and a more excellent black-and-white display can be obtained.

According to another embodiment of the present invention, the phase difference plate 28 is a lower electrode of a liquid crystal cell. It can be arranged between the substrate 24 and the lower polarizing plate 29. At this time, the retardation plate, the lower electrode substrate, and the lower polarizing plate are closely adhered to each other via an adhesive layer made of an adhesive. As described above, the liquid crystal cell and the retardation plate are formed between the input panel 31 and the liquid crystal cell 21 without an air layer between them, as in the embodiment of FIG. By arranging them on the same side with respect to the air layer to be formed, coloring due to surface reflection of the retardation plate or the liquid crystal cell can be prevented.

In addition, by applying a non-glare or anti-reflection treatment to the surface of the upper polarizing plate 37 or attaching an anti-reflection film to the surface, the effect of specular reflection from the upper polarizing plate 37 surface is obtained. And display can be improved.

(2) According to still another embodiment, the reflecting plate 30 can be a semi-transmissive reflecting plate, and a light source can be provided on the back or side of the reflecting plate. As a result, when ambient light is dark, a high contrast good black-and-white display can be obtained by using a pack light as in the case of bright ambient light.

Further, in the above-described embodiment, the input electrode substrates 32 and 33 are separated from the input panel 31 at a fixed interval by the spacer 34, and the upper and lower electrodes are connected by pressing with a finger or the like. Although a structure with a different structure was used, a structure with a different structure can be used as well. For example, an input panel in which electrodes are formed on both sides of a transparent insulating substrate and coordinates are determined by resistance, voltage, or current from the position contacted with a stylus pen, etc. Although there is no layer, the present invention can be similarly applied depending on the positional relationship between the input panel and the liquid crystal cell.

Further, according to the present invention, the liquid crystal display device of each embodiment described above can be mounted as a display means on a small portable information terminal device such as a portable telephone, an electronic organizer, and a palmtop computer. In this case, high contrast Since a black-and-white display with an easy-to-see ratio can be obtained, the display capacity can be made larger than before, and the easiness of use and the performance of the device can be improved. Examples 1 to 7 will be described below as specific examples of the liquid crystal display device with an input function according to the present invention.

(Example 1)

In the liquid crystal display device shown in FIG. 1, the Nippon Denko polarizing plate N PF—G 1 2 25 D U is placed on the upper polarizing plate 37, and the thickness is placed on the upper electrode substrate 32 of the input panel 31.

A polyethersulfone film having a thickness of 100 m and a retardation of 8 nm was used, and a glass plate having a thickness of 0.7 mm was used for the lower electrode substrate 33 of the input panel 31. The upper polarizing plate was stuck on the upper electrode substrate 32 of the input panel with an adhesive. The phase difference plate 28 is made of a uniaxially stretched polycarbonate film with a thickness of 120 m and a retardation of 60 Onm. An adhesive material is applied to the upper surface of the upper electrode substrate 23 of the liquid crystal cell. Affixed. Glass plates having a thickness of 0.7 mm were used for the upper and lower electrode substrates 23 and 24 of the liquid crystal cell. As the lower polarizing plate 29, a polarizing plate NPF-F3225M with a reflection plate manufactured by Nitto Denko was used, which was adhered to the lower surface of the lower electrode substrate 24 of the liquid crystal cell with an adhesive. In addition, the input panel 31 and the liquid crystal cell 21 were separated from each other by using silicon rubber of an appropriate length of 3 mra and a height of 0.5 country as a spacer.

Each angle in FIG. 2 was set to HI = 20 °, = 17.0 °, 7 = 50 °, and 度 = 240 °. For the liquid crystal 27, a nematic liquid crystal having a refractive index anisotropy Δn force of 0.132 is used, and the liquid crystal cell 21 is filled so that the layer thickness d is 6.3 m. The product Δn · d of the anisotropy Δn and the liquid crystal layer thickness d was 0.83 m. Also, an appropriate amount of an optically active agent was added so that the twist angle of the liquid crystal molecules was stabilized at 240 degrees.

As a result, it is bright enough when no voltage is applied (off state) and when voltage is applied.

Good contrast black-and-white display that is sufficiently dark (on) Was. In the first embodiment, the brightness in the ON state (dark) and the OFF state (bright) and the contrast ratio (off-state brightness Z) of the time-division driving with the duty ratio of 1/240 are described. The brightness in the ON state was measured, and the results in Table 1 below were obtained. Here, the “brightness” is the reflected light when irradiating the liquid crystal display device with input function with the same light as irradiating the standard white plate, when the reflected light from the standard white plate is 100 It is an index that indicates the strength of

(Example 2)

The configuration was the same as in Example 1, except that the upper electrode substrate 32 of the input panel 31 was replaced with the polyethersulfone 'film of Example 1, but had a thickness of 120 μm and a retardation of 6 nm. Polycarbonate film was used. Except for this point, a liquid crystal display device was configured.

As in Example 1, the brightness and contrast ratio in the ON state and the OFF state when the duty ratio was 1Z240 and time-division driving was measured.The results shown in Table 1 below were obtained. .

(Comparative example)

As a comparative example with respect to the first and second embodiments, a liquid crystal display device with an input function having a conventional structure shown in FIG. In addition, the brightness and the contrast ratio in the off state were measured. The measurement results are shown in Table 1 below together with Examples 1 and 2.

In the liquid crystal display device shown in FIG. 3, the upper polarizer 8 is provided with a Nitto Denko polarizing plate NPF—G1225-DU, and the upper electrode substrate 14 of the input panel 12 is provided with a thickness of 120 m and a retarder. A polyethylene terephthalate film with a length of 1 m or more was used, and a 0.7 mra thick glass plate was also used for the lower electrode substrate 15. The retarder 10 has a thickness of 120 2111 and a retardation of 600 nm. The axis-stretched polycarbonate film is used.The upper and lower electrode substrates 5 and 6 of the liquid crystal cell 1 are made of 0.7-thick glass plates, and the lower polarizing plate 9 is made of Nitto Denko. A polarizing plate with a reflector NPF-F325M was used. In addition, the input panel 12 and the liquid crystal cell 1 were separated from each other by using silicone rubber having a suitable width of 3 mm and a height of 0.5 mm as a spacer.

The liquid crystal display element of the comparative example can also express the orientation direction of liquid crystal molecules, the direction of the slow axis of the retardation plate, and the direction of the polarization axis of the polarizing plate as defined in FIG. = 20 degrees, = 170 degrees, 7 = 50 degrees, and S = 240 degrees. The liquid crystal 7 is made of a nematic liquid crystal having a refractive index anisotropy Δn of 0.132, and is filled in a liquid crystal cell so that the layer thickness d is 6.3 m. The product Δη · εΙ of Δn and the liquid crystal layer thickness d was set to 0.83. An appropriate amount of an optically active agent was added so that the twist angle of the liquid crystal molecules was stabilized at 240 degrees. As a result, a liquid crystal display which was bright when no voltage was applied and became small when voltage was applied was obtained. Table 1 Example 1 Example 2 Comparative example

As can be seen from the above Table 1 by comparing Example 1 with Comparative Example, Example 1 has slightly lower brightness in the off state than Comparative Example, but has significantly improved contrast ratio. Similarly, in the case of the second embodiment, the contrast ratio is clearly much higher than that of the comparative example, and is even better than that of the first embodiment. ing.

This is because the conventional liquid crystal display device with an input function device used in the comparative example has strong reflection light from the surface of the liquid crystal cell and the input panel. Since this reflected light overlaps the display in both the off state and the on state of the liquid crystal display element, the brightness in the off state is correspondingly reduced, and the power contrast ratio is reduced, thereby deteriorating the display quality. On the other hand, in Example 1 and Example 2, since the polarizing plate was disposed above the input panel, the reflected light from the liquid crystal cell surface and the input panel became smaller than before, and the brightness in the off state was compared. This is because, although smaller than the example, the amount of light incident on the liquid crystal cell does not change, so that the contrast is improved by reducing reflected light compared to the comparative example, and the display becomes easier to see.

Further, in both Example 1 and Example 2, it was confirmed that good black-and-white display without coloring was obtained. This is because the amount of light that passes through the retardation plate but does not pass through the liquid crystal cell is significantly reduced because the amount of light reflected from the surface of the liquid crystal cell is small as described above.

(Example 3)

In the same manner as in Example 1, a polarizing plate NPF—G1225DU manufactured by Nitto Denko was used for the upper polarizing plate 37, and a 100-m-thick, retardation 8 nm An ether sulfone film was used, and a glass plate having a thickness of 0.7 was used for the lower electrode substrate 33 in the same manner. For the upper and lower electrode substrates 23 and 24 of the liquid crystal cell, a 0.7-thick glass plate is used, and for the lower polarizer 29, a polarizing plate with a reflector made by Nitto Denko NPF-F3 is used. 225 M was used. The retardation plate 28 was made of a uniaxially stretched polycarbonate 'film having a thickness of 120 m and a retardation of 600 nm. However, unlike in Example 1, the lower electrode substrate of the liquid crystal cell was used. It was arranged between 24 and the lower polarizing plate 29. The liquid crystal cell, the retardation plate, and the lower polarizing plate were each adhered with an adhesive. Ma In addition, the input panel 31 and the liquid crystal cell 21 were similarly separated from each other by using silicone rubber of a suitable length of 3 mm and a height of 0.5 country as a spacer.

Each angle in FIG. 2 was set to 100 degrees, 70 degrees, 7 degrees 130 degrees, and 240 degrees. Using a nematic liquid crystal with a refractive index anisotropy Δn force of 0.132, the liquid crystal cell 21 is filled so that the layer thickness d becomes 6.3 jum, and the refractive index anisotropy Δn and the layer thickness The product of d A n 'd is 0.83〃m. Also, an appropriate amount of an optically active agent was added so that the twist angle of the liquid crystal molecules was stabilized at 240 degrees.

As a result, similar to Examples 1 and 2, in the liquid crystal display which is bright when no voltage is applied and dark when voltage is applied, a favorable white display with a higher contrast than before is obtained.

(Example 4)

A retardation film 28 was formed in the same manner as in Example 1 except that a twisted-oriented acrylic liquid crystalline polymer film was used for the retardation plate 28 instead of the uniaxially stretched polycarbonate film. The product Δ · ο! Of the refractive index anisotropy Δn of the liquid crystalline polymer and the thickness d of the liquid crystalline polymer is 0.7 2 / im, the twist angle of the liquid crystalline polymer is 150 °, The direction of the twist was opposite to that of the liquid crystal of the liquid crystal cell 21. The angles in FIG. 2 are as follows: α = 60 °, / 3/3, where the direction 42 of the slow axis of the retardation plate is the direction of the optical axis of the liquid crystalline polymer on the side of the retardation plate that contacts the liquid crystal cell. = 75 degrees, 7 = 45 degrees, and 0 = 220 degrees.

Also in this case, similarly to the above-described embodiments, in a liquid crystal display which is bright when no voltage is applied and becomes dark when a voltage is applied, the contrast ratio is improved as compared with the related art, and a good monochrome display is obtained.

(Example 5)

The structure was the same as in Examples 1 to 4, except that the upper polarizing plate 37 had a non-glare-treated Nitto Denko polarizing plate NPF-G1225DUA. G30 was used. As a result, the reflection of an image due to specular reflection on the upper polarizing plate surface was eliminated, and the display became much easier to see.

Similarly, when the surface of the normal upper polarizing plate 37 is subjected to anti-reflection treatment or when an anti-reflection treated film is adhered, the reflection of an image can be similarly reduced. Was.

(Example 6)

The same configuration as in Examples 1 to 5 was used, except that a polarizing plate with a transflective reflector NPF-F4205P3 manufactured by Todenko was used for the lower polarizing plate 29, and the lower polarizing plate 29 was used. A backlight was installed below. As a result, in an environment where the ambient light is dark, sufficient brightness and a good contrast ratio are obtained by turning on the backlight, and an excellent black-and-white display is obtained as in the case where the ambient light is bright. .

(Example 7)

When the liquid crystal display elements of Examples 1 to 6 were mounted on a display device of an electronic organizer or a mobile phone, an easy-to-read black-and-white display with a high contrast ratio was obtained. Also, since the contrast ratio is higher than before, the display capacity can be made larger than before, and more information can be displayed than before. It has become possible to improve and make it easier to use.

Claims

Scope of word blue

1. A liquid crystal cell sandwiching a liquid crystal between a pair of opposing electrode substrates, first and second polarizers disposed on the display surface side of the liquid crystal cell and on the opposite side thereof, respectively. A phase difference plate closely contacted with the surface, a reflector disposed outside the second polarizing plate, and an input panel having a pair of input electrodes separated at a fixed interval, wherein the input panel is A liquid crystal display device with an input function, which is disposed between the first polarizing plate and the liquid crystal cell.

2. The liquid crystal according to claim 1, wherein the input panel has a pair of input electrode substrates separated at a fixed interval, and the pair of input electrodes is provided on the opposing surfaces thereof. Display element.

3. The liquid crystal display device according to claim 1, wherein the retardation plate is disposed on a display surface side of the liquid crystal cell.

4. The liquid crystal display device according to claim 1, wherein the retardation plate is disposed between the liquid crystal cell and the second polarizing plate.

δ. The liquid crystal display device according to any one of claims 1 to 4, wherein the reflector is translucent.

6. The liquid crystal display device according to claim 1, wherein the liquid crystal is a nematic liquid crystal that is twist-aligned in a range of 180 degrees to 360 degrees.

7. The liquid crystal display device according to claim 1, wherein the retardation plate is an optically anisotropic polymer film.

8. The liquid crystal display device according to claim 7, wherein the optically anisotropic polymer film is a uniaxially stretched film.

9. The optically anisotropic polymer film is made of polycarbonate or polysulfo. 9. The liquid crystal display device according to claim 8, wherein the liquid crystal display device is selected from the group consisting of polystyrene, polyvinyl alcohol, polyether sulfone, polyacrylate, polyolefin, and polymethyl methacrylate.

10. The liquid crystal display device according to claim 7, wherein the optically anisotropic polymer film is a twisted-aligned liquid crystalline polymer film.

1 1. At least one of the input electrode substrates of the input panel is made of polycarbonate, polysulfone, polyvinyl alcohol, polyethersulfone, polyarylate, polyolefin, polymethylmethacrylate, or glass. 3. The liquid crystal display device according to claim 2, wherein:

12. The liquid crystal display device according to claim 1, wherein the surface of the first polarizing plate is non-glare treated.

13. The liquid crystal display device according to claim 1, wherein a retardation of the input panel is 5 O nm or less.

14. An electronic device comprising the liquid crystal display element according to any one of claims 1 to 13 as display means.