TWI477850B - Liquid crystal display device - Google Patents

Description

Liquid crystal display device

The present invention relates to a liquid crystal display device, and more particularly to a liquid crystal display device in which two layers are formed by laminating a liquid crystal cell.

There has been known a liquid crystal display device which is configured such that a liquid crystal cell which is held by a polarizing plate up and down and whose liquid crystal layer is disposed with a predetermined twist angle passes through or does not penetrate light in the up and down direction. The desired display is performed (see, for example, Patent Document 1 below). An example of the liquid crystal display device described above is a liquid crystal display device 200 having a liquid crystal layer 240 as shown in Figs. 10 and 11. For the convenience of explanation, the directions of the arrows shown in FIGS. 10 and 11 will be described as the front, rear, left, and right directions. As shown in Fig. 11, the alignment direction of the liquid crystal molecules constituting the liquid crystal layer 240 is formed such that the arrow 241 is rotated clockwise by 90 degrees in the lower end portion and the arrow 241 is rotated clockwise in the upper end portion by 90 in the front and rear left and right directions. The direction of the arrow 246 is a TN (Twisted Nematic) method in which the alignment direction is gradually twisted in the intermediate portion thereof.

Further, the liquid crystal layer 240 is vertically supported by the alignment film 232, and transparent electrodes 233 and 235 are disposed on the upper and lower outer sides of the alignment film 232, and the transparent electrode 235 is electrically connected to the AC power supply 236. Further, the transparent electrodes 233 and 235 are held up and down by the substrate 231, and the liquid crystal molecules of the liquid crystal layer 240 are sealed by the substrate 231 and the sealing member 234. The liquid crystal cell 230 is configured by the substrate 231, the sealing member 234, the transparent electrodes 233 and 235, the alignment film 232, and the liquid crystal layer 240. The liquid crystal cells 230 are vertically supported by the polarizing plates 203 and 204, and the transmission axis direction 203a of the polarizing plate 203 and the transmission axis direction 204a of the polarizing plate 204 are arranged in parallel. Further, a backlight 202 is disposed below the polarizing plate 203.

In the liquid crystal display device 200 having the above configuration, the illumination light from the backlight 202 is irradiated to the liquid crystal cell 230, and the illumination light 202a is rotated clockwise in the liquid crystal cell 230 along the twist angle of the liquid crystal molecules in the liquid crystal layer 240 to change the polarization. The direction reaches 90 degrees and reaches the polarizing plate 204. At this time, as shown in FIG. 11, since the transmission axis direction 204a of the polarizing plate 204 and the direction of the arrow 246 are rotated by 90 degrees, the illumination light 202a cannot penetrate the polarizing plate 204, and this part becomes dark display.

On the other hand, when a voltage is applied to the transparent electrode 235 by the AC power supply 236, the liquid crystal molecules in the liquid crystal layer 240 are arranged with their long axes arranged vertically. Therefore, the illumination light 202b that has traveled to the voltage application portion is not twisted by the liquid crystal molecules in the liquid crystal layer 240 to reach the polarizing plate 204. That is, since the illumination light 202b reaches the polarizing plate 204 in the alignment direction of the arrow 241, the illumination light 202b penetrates the polarizing plate 204 and is brightly displayed (negative display). From this, it is understood that a plurality of transparent electrodes 235 are disposed by forming a desired pattern, and voltage application control from the AC power source is performed for each of the transparent electrodes, and the pattern can be displayed in light and dark (black and white). Further, by rotating the polarizing plate 204 by 90 degrees in the front-rear and left-right directions, for example, a configuration (positive display) in which the desired pattern is darkly displayed in the background display that is displayed brightly is possible.

Patent Document 1: Japanese Patent Laid-Open Publication No. 2006-235581

However, the liquid crystal display device 200 described above is a negative display that causes a desired pattern to be brightly displayed in a background display that is displayed in a dark manner. Therefore, there is a problem in that, in a bright environment in which ambient light is surrounded by external light, the background display is brightly visible by external light, and the contrast between the desired image and the background display is highlighted. The difference is small, and the visual confirmation of the desired pattern is lowered.

Further, since the liquid crystal molecules in the liquid crystal layer 240 are uniaxial birefringence crystals having an optical axis in the long axis direction thereof, they penetrate the short axis direction or the oblique direction of the liquid crystal layer 240. The illumination light 202c is affected by the birefringence, and a phase difference is generated as soon as the liquid crystal cell 230 is penetrated. Therefore, there is a problem in that the oblique illumination light 202c of the liquid crystal display device 200 is obliquely penetrated (when the liquid crystal display device 200 is viewed obliquely) due to the phase difference, and the illumination light 202b (the liquid crystal display is viewed from directly above) In the case of device 200, a change in hue is produced.

In view of the above problems, an object of the present invention is to provide a liquid crystal display device which is provided with high visibility which is not affected by the brightness of the surrounding environment, and which has little change in color tone when viewed obliquely.

In order to solve the above problems, the liquid crystal display device according to the first aspect of the invention has the following components:

The upper liquid crystal cell is sealed by a pair of upper side substrates arranged in parallel with each other, a pair of flat transparent upper electrodes arranged in parallel with the upper substrate between the upper substrates, and a layered shape between the pair of upper electrodes. The upper liquid crystal layer is formed;

The lower liquid crystal cell is composed of a lower substrate which is disposed in parallel with each other, a pair of flat transparent pair of lower electrodes arranged in parallel with the lower substrate between the lower substrate, and between the pair of lower electrodes It is configured by being sealed in a layered lower liquid crystal layer, and is bonded and disposed on the bottom surface of the upper liquid crystal cell. Further, the upper liquid crystal molecules constituting the upper liquid crystal layer are twisted in the first twist direction along the spiral axis parallel to the normal line of the upper substrate, and are located in the first twist direction, and constitute the lower liquid crystal molecules of the lower liquid crystal layer. It is twisted in the second twisting direction along the helical axis parallel to the normal line of the aforementioned lower substrate and in the second twisting direction. Further, one of the pair of upper electrodes and the pair of lower electrodes has a plurality of pattern electrodes forming a desired pattern among the entire electrodes (for example, the outer peripheral portion 101 in the embodiment) forming the entire display region (for example, the outer peripheral portion 101 in the embodiment) For example, in the pattern 102) in the embodiment, the other one of the pair of upper electrodes and the pair of lower electrodes sandwiches at least a part of the upper liquid crystal molecules or at least a part of the lower liquid crystal molecules. At this time, each of the plurality of pattern electrodes is controlled by applying a voltage to the entire display area displayed by the bright display or the dark display, and the desired pattern is displayed in a light-dark display opposite to the entire display area, and By applying a voltage to the other electrode, changing an alignment direction of at least a portion of the upper liquid crystal molecules or an alignment direction of at least a portion of the lower liquid crystal molecules to a direction parallel to a normal to the upper substrate or parallel to The direction of the normal line of the lower substrate causes the display of at least a portion of the display region and at least a portion of the desired pattern to be reversed.

In the liquid crystal display device having the above configuration, the first twist direction and the second twist direction are opposite directions, a twist angle toward the first twist direction of the upper liquid crystal molecules, and a second angle toward the lower liquid crystal molecules The torsion angle of the twisting direction is 90 degrees or more and preferably less than 180 degrees. Further, in the liquid crystal display device having the above configuration, the alignment direction of the upper liquid crystal molecules located in the vicinity of the lower end of the upper liquid crystal layer and the alignment direction of the lower liquid crystal molecules located in the vicinity of the upper end of the lower liquid crystal layer are 90 degrees or The opposite direction of 180 degrees is preferred.

Further, in the liquid crystal display device having the above configuration, a pretilt angle of the upper liquid crystal molecules located in the vicinity of the upper end of the upper liquid crystal layer and a pretilt angle of the lower liquid crystal molecules located in the vicinity of the lower end of the lower liquid crystal layer An angle having a reverse direction and a slightly the same size, a pretilt angle of the upper liquid crystal molecules located near the lower end of the upper liquid crystal layer and a pretilt angle of the lower liquid crystal molecules located near the upper end of the lower liquid crystal layer have opposite directions and slightly Angles of the same size are preferred. Further, in the liquid crystal display device having the above configuration, the pair of upper electrodes and the pair of lower electrodes are preferably formed of a transparent electrode such as ITO (Indium Tin Oxide).

On the other hand, the liquid crystal display device relating to the second aspect of the invention has the following components:

The upper liquid crystal cell is composed of a pair of transparent upper substrates arranged in parallel with each other and an upper liquid crystal layer sealed in a layer between the pair of upper substrates;

The lower liquid crystal cell is composed of a pair of transparent lower substrates arranged in parallel with each other and a lower liquid crystal layer sealed in a layer between the pair of lower substrates, and is bonded and disposed on the upper liquid crystal cell Bottom surface

The upper polarizing plate penetrates a linear polarized light in a predetermined transmission axis direction and is joined to a top surface of the upper liquid crystal cell; and

The lower polarizing plate penetrates linearly polarized light in a predetermined transmission axis direction and is joined to the bottom surface of the lower liquid crystal cell. At this time, the upper liquid crystal molecules constituting the upper liquid crystal layer are twisted in the first twist direction along the spiral axis parallel to the normal line of the upper substrate, and are located in the first twist direction, and constitute the lower liquid crystal of the lower liquid crystal layer. The molecules are twisted in a second twist direction along a helical axis parallel to a normal line of the lower substrate and are located in a second twist direction, wherein the first twist direction and the second twist direction are opposite directions. Further, the pretilt angle of the upper liquid crystal molecules located in the vicinity of the upper end of the upper liquid crystal layer and the pretilt angle of the lower liquid crystal molecules located in the vicinity of the lower end of the lower liquid crystal layer have opposite angles and slightly the same size, on the upper side The pretilt angle of the upper liquid crystal molecules in the vicinity of the lower end of the liquid crystal layer and the pretilt angle of the lower liquid crystal molecules located in the vicinity of the upper end of the lower liquid crystal layer have opposite angles and slightly the same size. Further, the alignment direction of the upper liquid crystal molecules located in the vicinity of the lower end of the upper liquid crystal layer is opposite to the alignment direction of the lower liquid crystal molecules located in the vicinity of the upper end of the lower liquid crystal layer by 180 degrees.

Further, in the liquid crystal display device having the above configuration, the twist angle in the first twist direction of the upper liquid crystal molecules and the twist angle in the second twist direction of the lower liquid crystal molecules are 90 degrees or more. More than 180 degrees is better. Further, the upper liquid crystal molecules and the lower liquid crystal molecules are preferably formed of twisted nematic liquid crystals having the same birefringence characteristics.

Further, in the liquid crystal display device having the above configuration, the predetermined transmission axis direction of the upper polarizing plate and the alignment direction of the upper liquid crystal molecules in the vicinity of the upper end of the upper liquid crystal layer, and the predetermined transmission axis direction of the lower polarizing plate It is preferable that at least one of the alignment directions of the lower liquid crystal molecules located in the vicinity of the lower end of the lower liquid crystal layer is slightly parallel.

[Effect of the invention]

According to the liquid crystal display device according to the first aspect of the invention, the alignment direction of the upper liquid crystal molecules held by the other electrode or the alignment of the lower liquid crystal molecules is instantaneously performed by a simple method of applying a voltage to the other electrode. The direction changes to a direction parallel to the normal of the upper substrate, or to a direction parallel to the normal of the lower substrate. According to this, the brightness of at least a part of the entire display area and at least a part of the desired display pattern can be appropriately reversed according to the brightness of the surrounding environment, and the light and dark display in which the display area and the desired pattern are clearly displayed (contrast) can be selected. It is not affected by the brightness of the surrounding environment, and it can perform liquid crystal display with high visual confirmation.

In the device, if the first twisting direction and the second twisting direction are opposite directions, the twist angle of the first twisting direction of the liquid crystal molecules toward the upper side and the twisting angle of the second twisting direction of the liquid crystal molecules facing the lower side are 90 degrees. When the temperature is 90 degrees or more and less than 180 degrees, the illumination light incident on each liquid crystal layer is not twisted in the incident polarization direction and does not emit the liquid crystal layers, so that the liquid crystal display device can be made clear ( Contrast high) display.

Further, when the alignment direction of the liquid crystal molecules on the upper side near the lower end of the upper liquid crystal layer is opposite to the alignment direction of the lower liquid crystal molecules located near the upper end of the lower liquid crystal layer, the upper side liquid is formed. In the vicinity of the lower end of the crystal layer and the portion near the upper end of the lower liquid crystal layer, even if the illumination light obliquely traverses the liquid crystal molecules, the influence of the birefringence from the liquid crystal molecules can be compensated. Further, the illumination light emitted from the liquid crystal display device can be emitted in a state of linearly polarized light without changing to elliptically polarized light. Therefore, the difference in brightness and contrast between the entire display area and the desired pattern can be clearly displayed, and a liquid crystal display having high visibility can be performed.

Further, liquid crystal molecules in the vicinity of the upper end of the upper liquid crystal layer and the lower end of the lower liquid crystal layer, and liquid crystal molecules in the vicinity of the lower end of the upper liquid crystal layer and the upper end of the lower liquid crystal layer have opposite directions and are slightly the same size. In the tilting angle, the illumination light traveling obliquely (when the liquid crystal display device is viewed obliquely), the phase difference generated in one of the upper liquid crystal layer and the upper liquid crystal layer can be made by the liquid crystal on the other side. The completely opposite phase differences given in the layers cancel each other out. Therefore, the illumination light obliquely emitted by the liquid crystal display device does not have a phase difference, and can be displayed without a change in color tone in comparison with the illumination light that travels straight.

Further, the ITO electrode is formed by a pair of upper electrodes and a pair of lower electrodes, and can be configured to be transparent, whereby the progress of the illumination light penetrating the electrodes is not hindered. Therefore, in the upper liquid crystal cell and the lower liquid crystal cell, the illumination light is not attenuated and is emitted by the liquid crystal display device, and the difference between the display area and the desired pattern can be clearly displayed, and the high visibility can be performed. Confirmatory LCD display.

Further, according to the liquid crystal display device of the second aspect of the invention, the first twist direction of the upper liquid crystal molecules is opposite to the second twist direction of the lower liquid crystal molecules, and the liquid crystal molecules are located above the upper end of the upper liquid crystal layer. a pretilt angle of the liquid crystal molecules on the lower side near the lower end of the lower liquid crystal layer, and a pretilt angle of the liquid crystal molecules on the upper side near the lower end of the upper liquid crystal layer and liquid crystal molecules on the lower side near the upper end of the lower liquid crystal layer The pretilt angle is constituted by an angle having a reverse direction and a slightly equal size, and the alignment direction of the liquid crystal molecules on the upper side near the lower end of the upper liquid crystal layer and the alignment direction of the liquid crystal molecules on the lower side near the upper end of the lower liquid crystal layer are 180 degrees in the opposite direction. That is, the upper liquid crystal layer and the lower liquid crystal layer are vertically symmetrically arranged. According to the above configuration, for example, when the illumination light travels obliquely upward from the lower side to the liquid crystal display device, the phase difference given in the lower liquid crystal layer is given to the phase difference generated in the lower liquid crystal layer in the upper liquid crystal layer. Completely opposite phase differences, which cancel each other out (compensate) the phase difference. Therefore, the illumination light that travels in the oblique direction is emitted from the liquid crystal display device without the phase difference, and thus it is difficult to cause a change in color tone when the liquid crystal display device is viewed obliquely.

In this device, when the twist angle of the first twist direction of the liquid crystal molecules toward the upper side and the twist angle of the second twist direction of the liquid crystal molecules facing downward are 90 degrees or more and less than 180 degrees, the incident is performed. The illumination light of each liquid crystal layer is not twisted in the incident polarization direction and does not emit the liquid crystal layers, so that the liquid crystal display device can perform vivid display.

Further, when the upper liquid crystal layer and the lower liquid crystal layer are temperature-changed in the two liquid crystal layers (two liquid crystal molecules), if a chiral material which slightly maintains the twist pitch of the two liquid crystal molecules is added, Further, even in the case where temperature changes occur in the two liquid crystal layers, since the twist pitch of the two liquid crystal molecules is kept slightly the same, the upper symmetrical structure of the upper liquid crystal layer and the lower liquid crystal layer is maintained and travels in the oblique direction. The illumination light is emitted from the liquid crystal display device without a phase difference, so that the color tone change can be made more difficult when the liquid crystal display device is viewed obliquely.

Further, if the predetermined transmission axis direction of the upper polarizing plate is opposite to the alignment direction of the liquid crystal molecules on the upper side near the upper end of the upper liquid crystal layer, and the predetermined transmission axis direction of the lower polarizing plate and the lower side liquid crystal near the lower end of the lower liquid crystal layer When at least one of the alignment directions of the molecules is formed in a substantially parallel manner, when the illumination light is incident on the upper side of the upper polarizing plate which is formed slightly parallel or the lower side of the lower polarizing plate, only the linear polarization of the predetermined transmission axis direction is caused. After traveling in the upper liquid crystal cell and the lower liquid crystal cell, it can be emitted from the liquid crystal display device, and a clear display without circularly polarized light can be performed.

Hereinafter, preferred embodiments of the liquid crystal display device 1 according to the present invention will be described with reference to Figs. 1 to 7 . Further, for convenience of explanation, the directions of the arrows shown in the respective drawings will be described as the front, rear, left, and right directions. As shown in FIG. 1, the liquid crystal display device 1 is mainly composed of a backlight 2, a lower polarizing plate 3, an upper polarizing plate 4, a reverse control liquid crystal cell 10, and a display liquid crystal cell 30.

The inversion control liquid crystal cell 10 is formed in a flat shape by the substrate 11, the alignment films 12a and 12b, the transparent electrodes 13a and 13b, the sealing member 14, the AC power source 16, the changeover switch 17, and the liquid crystal layer 20. The liquid crystal layer 20 is composed of a twisted nematic liquid crystal material, and liquid crystal molecules having a regular alignment direction are laminated to form a layer, and have birefringence in the short axis direction and optical uniaxiality without birefringence in the long axis direction. Birefringent crystals. An optically active material having a pitch for controlling the twist of the liquid crystal molecules to the nematic liquid crystal is added to the twisted nematic liquid crystal material. Further, the optically active material is, for example, an optically active nematic liquid crystal or a cholesteric liquid crystal.

The alignment films 12a and 12b are subjected to alignment treatment (rubbing treatment) on one side thereof. The liquid crystal molecules of the liquid crystal layer 20 are aligned in such a direction that their major axes coincide. Further, the liquid crystal molecules are formed to have a pretilt angle of about 2 to 10 degrees to the surface of the alignment film 12. Further, the pretilt angle is determined by the materials of the alignment films 12a and 12b and the liquid crystal molecules.

The transparent electrodes 13a and 13b are formed of, for example, an ITO electrode in which a small amount of tin oxide to indium oxide is added, and are formed in a flat shape and transparent, and a voltage can be applied from the outside. The AC power source 16 is electrically connected to the transparent electrodes 13a and 13b, and a voltage can be applied across the transparent electrodes 13a and 13b. The changeover switch 17 is provided in a circuit that electrically connects the transparent electrodes 13a and 13b and the AC power source 16. By turning the switch 17 on or off, it is possible to arbitrarily switch whether or not a voltage is applied to the transparent electrodes 13a and 13b through the AC power source 16.

The substrate 11 is a planar substrate formed using, for example, transparent glass, and can transmit illumination light irradiated by the backlight 2. The sealing member 14 is formed of a material in which liquid crystal molecules of the liquid crystal layer 20 are osmosis, and the liquid crystal molecules of the liquid are prevented from flowing out to the outside by the sealing member 14, and contamination substances from the outside are prevented from flowing into the liquid crystal layer 20 .

The liquid crystal cells 30 are formed in a flat shape by the substrate 31, the alignment films 32a and 32b, the lower transparent electrodes 33a and 35a, the upper transparent electrodes 33b and 35b, the sealing member 34, the AC power source 36, and the liquid crystal layer 40. Like the liquid crystal layer 20, the liquid crystal layer 40 is formed using a twisted nematic liquid crystal material, and an optically active material is added to the twisted nematic liquid crystal material. Here, the characteristics and the amount of addition of the optically active material are adjusted, and when the temperature of the liquid crystal layer changes, the change in the twist pitch of the liquid crystal molecules (the temperature characteristic of the liquid crystal) is equal between the liquid crystal layer 20 and the liquid crystal layer 40. The alignment films 32a and 32b are formed by rubbing treatment in the same manner as the alignment film 12 described above.

Each of the transparent electrodes 33a, 33b, 35a, and 35b is formed of a transparent conductive film, and the lower transparent electrode 35a and the upper transparent electrode 35b are provided with a plurality of patterns, and the desired pattern is formed by ytterbium, and is supplied from the alternating current power source 36 by each of the electrodes. The voltage application control is configured by displaying the aforementioned pattern in black and white. Similarly to the above-described substrate 11, the substrate 31 is, for example, a planar substrate formed using transparent glass, and can penetrate the illumination light irradiated by the backlight 2. The sealing member 34 is formed of a material in which the liquid crystal molecules of the liquid crystal layer 40 do not penetrate, like the sealing member 14 described above. The AC power source 36 is electrically connected to the transparent electrode 35a and the transparent electrode 35b, and a voltage can be applied to each of the lower transparent electrode 35a and the upper transparent electrode 35b.

The lower polarizing plate 3 is a linear polarizing plate which is formed only by the linearly polarized light having the vibration of the transmission axis direction 3a shown in FIG. Similarly to the lower polarizing plate 3, the upper polarizing plate 4 is a linear polarizing plate which can penetrate only the linearly polarized light having the vibration of the transmission axis direction 4a shown in FIG. The backlight 2 is a light source that illuminates illumination light from the lower side of the lower polarizing plate 3.

The above has been described with respect to the component configuration of the liquid crystal display device 1, and the assembly structure of the liquid crystal display device 1 will be described below.

First, when the assembly structure of the liquid crystal cell 10 is reversely controlled, the reverse control liquid crystal cell 10 transmits the two substrates 11 on the upper and lower sides, and the front and rear sides and the left and right sides of the space held by the two substrates 11 are borrowed. A region where the liquid crystal layer 20 is formed by the sealing member 14 is formed. Further, a transparent electrode 13a is fixed to the top surface of the substrate 11 located below, and an alignment film 12a is fixed to the top surface of the transparent electrode 13a. On the other hand, the transparent electrode 13b is fixed to the bottom surface of the substrate 11 located above, and the alignment film 12b is fixed to the bottom surface of the transparent electrode 13b. Further, the transparent electrodes 13a and 13b are arranged to face each other in the vertical direction and are paired. Further, as described above, the transparent electrodes 13a and 13b are electrically connected to the alternating current power source 16.

The direction of the rubbing treatment of the alignment film 12a is, for example, parallel to the direction indicated by the arrow 21a in the front-rear and left-right directions as shown in Fig. 3, and the direction of the rubbing treatment of the alignment film 12b is, for example, parallel to the arrow. The direction shown in 26a. Further, the rubbing treatment direction of each of the alignment films 12a and 12b is at an angle of 90 degrees in the front-rear and left-right directions. In Fig. 5(b), a part of the liquid crystal molecules in the liquid crystal layer 20 in the vertical direction is schematically shown by the liquid crystal molecules 21 to 26. Further, the alignment direction (long-axis direction) of the liquid crystal molecules 21 to 26 in the front-rear and left-right directions is shown in Fig. 4(b), and the alignment directions of the liquid crystal molecules 21, 22, ... correspond to the directions of the arrows 21a, 22a, ..., respectively.

At this time, the liquid crystal molecules 21 and 26 located closest to the alignment films 12a and 12b are fixed by being aligned with the rubbing treatment direction, and these alignment directions are parallel to the rubbing treatment directions of the alignment films 12a and 12b. Further, the liquid crystal molecules 22 located below have a major axis direction which is slightly parallel to the direction of the arrow 21a, and the liquid crystal molecules 25 located above have a long axis direction which is slightly parallel to the direction of the arrow 26a. In other words, when the entire liquid crystal molecules 21 to 26 are viewed from above, their alignment directions are rotated clockwise by 90 degrees in the front-rear and left-right directions, and the directions are changed little by little and twisted and arranged.

Further, the liquid crystal molecules 21 and 26 located closest to the alignment films 12a and 12b are fixed in the left and right vertical directions as shown in Fig. 5(b), in a state parallel to the rubbing direction and inclined (pretilt angle) on the substrate surface. . In the right and left vertical directions, the liquid crystal molecules 21 are inclined at the pretilt angle θ1 with respect to the alignment film 12a, and the liquid crystal molecules 26 are inclined at the pretilt angle θ2 with respect to the alignment film 12b. The liquid crystal molecules 22 to 25 are arranged such that the liquid crystal molecules 22 from the lower portion of the liquid crystal layer 20 to the upper liquid crystal molecules 25 are gradually changed from slightly θ1 to slightly θ2 in the left and right vertical directions.

Next, the assembly configuration of the liquid crystal cells 30 will be described. The basic configuration is the same as that of the reverse control liquid crystal cell 10, and the liquid crystal layer 40 is formed by arranging two substrates 31 on the upper and lower sides, and the front and rear and left and right sides of the space held by the two substrates 31 are surrounded by the sealing member 34. Area. Further, transparent electrodes 33a and 35a are fixed to the top surface of the substrate 31 located below, and transparent electrodes 33b and 35b are fixed to the bottom surface of the substrate 31 located above. Here, the transparent electrodes 33a and 33b and the transparent electrodes 35a and 35b are They are arranged up and down and facing each other. Here, as described above, the transparent electrodes 35a and 35b are electrically connected to the AC power source 36. Further, an alignment film 32a is fixed to the top surface of the transparent electrodes 33a and 35a, and an alignment film 32b is fixed to the bottom surfaces of the transparent electrodes 33b and 35b. Further, the inversion control liquid crystal cell 10 and the display liquid crystal cell 30 are slightly the same in the vertical direction.

The direction of the rubbing treatment of the alignment film 32a is parallel to the direction indicated by, for example, the arrow 41a in the front-rear and left-right directions as shown in Fig. 3, and the direction of the rubbing treatment of the alignment film 32b is parallel to, for example, the arrow 46a. The direction. Further, the rubbing treatment direction of each of the alignment films 32a and 32b is at an angle of 90 degrees in the front-rear and left-right directions. In Fig. 5(a), a part of the liquid crystal molecules in the liquid crystal layer 40 in the vertical direction is schematically displayed by the liquid crystal molecules 41 to 46. Further, the alignment direction (long-axis direction) of the liquid crystal molecules 41 to 46 in the front-rear and left-right directions is shown in Fig. 4(a), and the alignment directions of the liquid crystal molecules 41, 42 are respectively corresponded to the directions of the arrows 41a, 42a, ....

The liquid crystal molecules 41 and 46 located closest to the alignment films 32a and 32b are aligned with the rubbing treatment direction and fixed, whereby the alignment directions are parallel to the rubbing treatment directions of the alignment films 32a and 32b. Further, the liquid crystal molecules 42 located below have a longitudinal direction which is slightly parallel to the direction of the arrow 41a, and the liquid crystal molecules 45 located above are substantially parallel to the direction of the arrow 46a. In other words, when the entire liquid crystal molecules 41 to 46 are viewed from above, their alignment directions are rotated counterclockwise by 90 degrees in the front-rear and left-right directions, and the directions are changed little by little and twisted and arranged.

Further, the liquid crystal molecules 41 and 46 located closest to the alignment films 32a and 32b are fixed in the left and right vertical directions as shown in Fig. 5(a), in a state parallel to the rubbing direction and inclined (pretilt angle) on the substrate surface. . In the right and left vertical directions, the liquid crystal molecules 41 are inclined at the pretilt angle θ3 with respect to the alignment film 32a, and the liquid crystal molecules 46 are inclined at the pretilt angle θ4 with respect to the alignment film 32b. The liquid crystal molecules 42 to 45 are arranged such that the liquid crystal molecules 42 from the lower portion of the liquid crystal layer 40 to the upper liquid crystal molecules 45 are gradually changed from slightly θ3 to slightly θ4 in the right and left vertical directions.

Next, an assembly configuration of the liquid crystal display device 1 including the inversion control liquid crystal cell 10 and the display liquid crystal cell 30 having the above configuration will be described.

In a state in which the liquid crystal cells 30 are fixed on the top surface of the inversion control liquid crystal cell 10, the above two fixed liquid crystal cells are held by the lower polarizing plate 4 from above by the lower polarizing plate 4. At this time, as shown in FIG. 3, the transmission axis direction 3a of the lower polarizing plate 3 and the rubbing treatment direction 21a (the alignment direction of the liquid crystal molecules 21) of the alignment film 12a are slightly the same, and the transmission axis direction 4a of the upper polarizing plate 4 is The rubbing treatment direction 46a (the direction in which the liquid crystal molecules 46 are aligned) of the alignment film 32b is in a positional relationship of 90 degrees of rotation. Further, the rubbing treatment direction 26a of the alignment film 12b (the alignment direction of the liquid crystal molecules 26) and the rubbing treatment direction 41a (the alignment direction of the liquid crystal molecules 41) of the alignment film 32a are parallel to each other and opposite directions (direction rotated by 180 degrees). Composition.

Further, the pretilt angles θ1 and θ4, the pretilt angles θ2 and θ3 are at substantially the same angle, and the liquid crystal molecules 22 and 45, the liquid crystal molecules 23 and 44, the liquid crystal molecules 24 and 43, and the liquid crystal molecules 25 and 42 each have slightly the same inclination angle. . Further, the backlight 2 is disposed below the lower polarizing plate 3, and the illumination light irradiated by the backlight 2 is configured to illuminate the liquid crystal cell 10 and the liquid crystal cell 30 (from the lower side upward).

The above description has been made on the assembly configuration of the liquid crystal display device 1, and the display method using the liquid crystal display device 1 described above will be described in the following first embodiment and second embodiment.

In the liquid crystal display device 1, if the illumination light from the backlight 2 is incident by the lower polarizing plate 3 and is penetrated by the upper polarizing plate 4, the portion is brightly displayed, and conversely, the portion of the illumination light that is not penetrated by the upper polarizing plate 4 becomes A state that is not displayed in the dark (no display). For example, a case where the number 1 of the transparent electrode 100 configured by using the displayable numbers 1 to 9 is displayed will be described. In the display liquid crystal cell 30 having the above configuration, seven patterns 102, 103, 104, ... as shown in Fig. 7 and a pair of transparent electrodes 100 having the outer peripheral portion 101 are used. The pair of transparent electrodes 100 are fixed in pairs between the substrate 31 located below and the alignment film 32a and between the substrate 31 located above and the alignment film 32b. Further, each of the patterns corresponding to the upper and lower sides (for example, the upper and lower patterns 102) is electrically connected to the alternating current power source 36.

With the above configuration, only voltage is applied to the portions of the patterns 102 and 103, and only the portions 102 and 103 of the illumination light are transmitted, and the digital 1 is brightly displayed. On the other hand, the other patterns 104 including the outer peripheral portion 101 partially illuminate the light without being penetrated but are displayed dark. In other words, the pattern portion that is intended to be brightly displayed is applied by applying only a voltage, and the illumination light is transmitted to perform a desired display.

[Example 1]

First, the method of traveling the illumination lights 2a and 2b for the negative display shown in FIG. 1 will be described as an example. The illumination light 2a is illumination light that travels up and down on the transparent electrodes 33a and 33b in the liquid crystal cell 30, and the illumination light 2b is illumination light that travels up and down on the transparent electrodes 35a and 35b to which voltage is applied. In the case of the negative display shown in Fig. 1, the changeover switch 17 is turned off, and the voltage is not applied to the transparent electrodes 13a and 13b by the AC power source 16.

The illumination light 2a irradiated by the backlight 2 becomes circularly polarized light 2e in a plane perpendicular to the traveling direction (up-and-down direction) as shown in Fig. 3, but by a line which penetrates the lower polarizing plate 3 and is parallel only to the transmission axis direction 3a. The polarized light is incident on the inversion control liquid crystal cell 10. The illumination light incident on the inversion control liquid crystal cell 10 travels from the lower side upward by the optical rotation of the liquid crystal molecules in the liquid crystal layer 20, and the twist angle of the liquid crystal molecules 21 to 26 (the length of the liquid crystal molecules 21 to 26) In the axial direction, the polarization direction is changed, and only the polarization direction is changed by 90 degrees in the front-rear and left-right directions, and the reverse rotation control liquid crystal cell 10 is emitted as the polarization direction in the direction of the arrow 26a, and is incident on the display liquid crystal cell 30.

Further, the illumination light 2a incident on the display liquid crystal cell 30 travels from the lower side upward due to the optical rotation of the liquid crystal molecules in the liquid crystal layer 40, and is caused to have a twist angle along the liquid crystal molecules 41 to 46 (liquid crystal molecules 41 to 46) The long axis direction) is rotated counterclockwise in the front, rear, left and right directions and changes the polarization direction by 90 degrees to reach the upper polarizing plate 4. The polarization direction of the illumination light 2a reaching the upper polarizing plate 4 is a direction indicated by an arrow 46a, and is a positional relationship in which the arrow 46a is orthogonal to the transmission axis direction 4a of the upper polarizing plate 4, so that the illumination light 2a cannot penetrate the upper polarized light. When the liquid crystal display device 1 is viewed from above the upper polarizing plate 4, the panel 4 is displayed in dark (no display).

On the other hand, the illumination light 2b irradiated by the backlight 2 enters the inversion control liquid crystal cell 10 like the illumination light 2a described above, and emits the inversion control liquid crystal cell 10 and enters the display liquid crystal cell 30.

Here, the transparent electrodes 35a and 35b are applied with a voltage by the AC power supply 36, and the inclined state in the right and left vertical directions of the liquid crystal molecules 41 to 46 at this time is shown in Fig. 6(a). As shown in Fig. 6(a), the liquid crystal molecules 41, 42, 45, and 46 in the vicinity of the alignment films 32a and 32b are fixed to the rubbing treatment direction of the alignment films 32a and 32b, and the inclination angle does not change before and after the application of the voltage. On the other hand, the liquid crystal molecules 43 and 44 in the intermediate portion are arranged along the long axis in the vertical direction along the electric power lines generated between the transparent electrodes 35a and 35b.

The liquid crystal molecules in the liquid crystal layer 40 are optically uniaxial birefringent crystals having birefringence in the short axis direction and birefringence in the long axis direction. Therefore, the illumination light 2b traveling in the liquid crystal layer 40 is not affected by the birefringence of the liquid crystal molecules, and travels along the long axis direction of the liquid crystal molecules in the liquid crystal layer 40, and the polarization direction does not change to reach the upper polarizing plate 4. . At this time, the polarization direction of the illumination light 2b reaching the upper polarizing plate 4 is the direction indicated by the arrow 41a, and the arrow 41a is parallel to the transmission axis direction 4a of the upper polarizing plate 4, so that the illumination light 2b penetrates the upper polarizing plate 4, When the liquid crystal display device 1 is viewed from above the upper polarizing plate 4, a bright display can be seen.

Further, when the illumination light 2b travels obliquely to the inversion control liquid crystal cell 10 and the display liquid crystal cell 30, the illumination light 2b is affected by the birefringence of each liquid crystal molecule to cause a phase difference. However, in the optical path in which the illumination light 2b travels, the liquid crystal molecules 21 and 46, the liquid crystal molecules 22 and 45, the liquid crystal molecules 25 and 42, and the liquid crystal molecules 26 and 41 respectively have a positional relationship in which the phase difference is compensated (compensated). As shown in Fig. 4 (a) and Fig. 4 (b), the liquid crystal molecules in the mutually compensated positional relationship are aligned directions which are opposite to each other (direction rotated by 180 degrees), and as shown in Fig. 5 (a) And as shown in Fig. 5(b), the tilt directions are opposite in the left and right vertical directions, and the tilt angles are slightly the same.

According to this, when the illumination light 2b travels, for example, to the liquid crystal molecules 46, a phase difference completely opposite to the phase difference generated in the liquid crystal molecules 21 is given, so that the phase difference generated in the liquid crystal molecules 21 is canceled. Similarly, in the other mutually compensated positional relationship liquid crystal molecules, the phase difference generated by the illumination light 2b in the inversion control liquid crystal cell 10 is canceled by the phase difference generated in the display liquid crystal cell 30. Therefore, when the illumination light 2b travels obliquely, the illumination light 2b penetrating the upper polarizing plate 4 does not have a phase difference, and thus does not cause a change in color tone as compared with the illumination light 2b that travels straight up and down.

That is, in the negative display shown in Fig. 1, the portions of the transparent electrodes 33a and 33b are darkly displayed, and the portions of the transparent electrodes 35a and 35b are brightly displayed. Therefore, by using a plurality of transparent electrodes 35a, 35b to form a desired pattern, and applying voltage control to each of the plurality of transparent electrodes 35a, 35b, the desired pattern can be brightly displayed on the darkly displayed background.

[Embodiment 2]

Next, a method of displaying the illumination lights 2c and 2d as shown in FIG. 2 will be described as an example. The illumination light 2c is illumination light that travels up and down on the transparent electrodes 33a and 33b in the liquid crystal cell 30, and the illumination light 2d is illumination light that travels up and down on the transparent electrodes 35a and 35b to which voltage is applied. In the case of the positive display shown in Fig. 2, the changeover switch 17 is turned "on", and the voltage of the alternating current power source 16 is applied to the transparent electrodes 13a, 13b.

The illumination light 2c irradiated by the backlight 2 becomes circularly polarized light 2e in a plane perpendicular to the traveling direction (up-and-down direction) as shown in Fig. 3, but by a line which penetrates the lower polarizing plate 3 and is parallel only to the transmission axis direction 3a. The polarized light is incident on the inversion control liquid crystal cell 10. At this time, since the voltage is applied to the transparent electrodes 13a and 13b, the liquid crystal molecules in the liquid crystal layer 20 are as shown in Fig. 6(b), and the liquid crystal molecules 21, 22, 25, 26 in the vicinity of the alignment films 12a and 12b are used. The rubbing treatment of the alignment films 12a and 12b is fixed to the alignment films 12a and 12b, and the inclination angle does not change before and after the application of the voltage. On the other hand, the liquid crystal molecules 23 and 24 in the intermediate portion are arranged along the long axis in the vertical direction along the electric power lines generated between the transparent electrodes 13a and 13b.

The liquid crystal molecules in the liquid crystal layer 20 are optically uniaxial birefringent crystals having birefringence in the short axis direction and birefringence in the long axis direction, like the liquid crystal molecules in the liquid crystal layer 40 described above. . Therefore, the illumination light 2c traveling in the liquid crystal layer 20 is not affected by the birefringence of the liquid crystal molecules, and travels along the long axis direction of the liquid crystal molecules in the liquid crystal layer 20, and the polarization direction does not change, as shown by an arrow 21a. The liquid crystal cell 10 is emitted by the inversion control in the direction.

The illumination light 2c emitted from the inversion control liquid crystal cell 10 is incident on the display liquid crystal cell 30. Further, the illumination light 2c incident on the display liquid crystal cell 30 changes the polarization direction by 90 degrees counterclockwise in the front-rear and left-right directions due to the optical rotation of the liquid crystal molecules in the liquid crystal layer 40, and reaches the upper polarizing plate 4. The direction of polarization of the illumination light 2c reaching the upper polarizing plate 4 is the direction indicated by the arrow 41a, and the arrow 41a is parallel to the transmission axis direction 4a of the upper polarizing plate 4, so that the illumination light 2c penetrates the upper polarizing plate 4, and The liquid crystal display device 1 is brightly displayed when viewed above the polarizing plate 4.

Further, when the illumination light 2c travels obliquely to the inversion control liquid crystal cell 10 and the display liquid crystal cell 30, the illumination light 2c is affected by the birefringence of each liquid crystal molecule to cause a phase difference. However, in the optical path in which the illumination light 2c travels, as in the case of the illumination light 2b described above, the liquid crystal molecules 21 and 46, the liquid crystal molecules 22 and 45, the liquid crystal molecules 25 and 42, and the liquid crystal molecules 26 and 41 respectively compensate each other (mutually Offset) the positional relationship of the phase difference. Therefore, in the case where the illumination light 2c travels obliquely, the illumination light 2c penetrating the upper polarizing plate 4 does not have a phase difference, and thus does not cause a change in color tone as compared with the illumination light 2c that travels straight up and down.

On the other hand, the illumination light 2d irradiated by the backlight 2 enters the inversion control liquid crystal cell 10 like the illumination light 2c, and emits the inversion control liquid crystal cell 10 without changing the polarization direction in the direction indicated by the arrow 21a. It is incident on the display liquid crystal cell 30.

The illumination light 2d incident on the display liquid crystal cell 30 travels inside the liquid crystal layer 40. At this time, the liquid crystal molecules in the liquid crystal layer 40 are in the state shown in FIG. 6( a ), and as in the case of the illumination light 2 b , the liquid crystal molecules travel along the long axis direction of the liquid crystal molecules, and the polarization direction does not change to reach the upper polarizing plate. 4. At this time, the polarization direction of the illumination light 2d reaching the upper polarizing plate 4 is the direction indicated by the arrow 21a, and the arrow 21a and the transmission axis direction 4a of the upper polarizing plate 4 are orthogonal to each other, so that the illumination light 2d cannot penetrate. When the liquid crystal display device 1 is viewed from above the upper polarizing plate 4, the upper polarizing plate 4 can be seen as a dark display.

That is, in the positive display shown in Fig. 2, the transparent electrodes 33a, 33b are partially illuminated, and the transparent electrodes 35a, 35b are partially displayed dark. Therefore, by using a plurality of transparent electrodes 35a, 35b to form a desired pattern, and applying voltage control to each of the plurality of transparent electrodes 35a, 35b, the desired pattern can be darkly displayed on the brightly displayed background.

Here, for the simplification of the effect of the liquid crystal display device 1 relating to the present invention, the liquid crystal display device 1 according to the present invention is switched between the negative display and the positive display (Embodiment 1 and Embodiment 2). By operation The changeover switch 17 is switched arbitrarily and instantaneously. Therefore, since it is possible to easily and immediately switch between the negative display and the positive display in accordance with the brightness of the surrounding environment in which the liquid crystal display device 1 is used, and display in a state where the contrast between the background and the display pattern is improved, it is not subject to the surrounding environment. The brightness influences and maintains high visual confirmation. When the liquid crystal display device 1 is mounted on a car as a liquid crystal display for an automobile, for example, it is possible to change the background and the display pattern by appropriately switching between the negative display and the positive display in any of the day and night when the surrounding brightness changes. Displayed in a contrasted state, high visual visibility can be maintained at all times.

Second, the illumination light that travels obliquely to the liquid crystal molecules located at the upper and lower positions corresponding to the liquid crystal layer 20 and the liquid crystal layer 40 obliquely cancels the phase difference. According to this, the phase difference generated in the liquid crystal layer 20 is canceled by the phase difference generated in the liquid crystal layer 40. Therefore, the illumination light emitted from the liquid crystal display device 1 does not have a phase difference, and can be displayed without a change in color tone as compared with the illumination light that travels straight. In other words, the viewing angle of the liquid crystal display device 1 can be increased.

In the above embodiment, the illumination light generated in the backlight 2 is first incident on the inversion control liquid crystal cell 10, and the illumination light emitted from the inversion control liquid crystal cell 10 is incident on the display liquid crystal cell 30, but may also be The configuration is such that, after the illumination light is incident on the display liquid crystal cell 30, the illumination light emitted from the display liquid crystal cell 30 is incident on the inversion control liquid crystal cell 10.

In the above-described embodiment, the liquid crystal molecules constituting the liquid crystal layer 20 of the reverse control liquid crystal cell 10 are clockwise rotated in the alignment direction in the front-rear and left-right directions. 90 degrees. On the other hand, the liquid crystal molecules constituting the liquid crystal layer 40 of the liquid crystal cell 30 are rotated counterclockwise by 90 degrees in the front-rear and left-right directions. Here, the twist direction (rotation direction) of the liquid crystal molecules is not limited to the above-described direction, and may be configured such that the alignment direction of the liquid crystal molecules of the liquid crystal layer 20 is rotated counterclockwise by 90 degrees to cause liquid crystal molecules of the liquid crystal layer 40. The alignment direction is rotated 90 degrees clockwise. Further, each of the above-described rotation angles is not limited to 90 degrees, and can be arbitrarily set in a range of 90 degrees or more and 90 degrees or less.

In the above-described embodiment, the rubbing treatment direction 26a (the alignment direction of the liquid crystal molecules 26) of the alignment film 12b and the rubbing treatment direction 41a (the alignment direction of the liquid crystal molecules 41) of the alignment film 32a are parallel to each other and opposite directions (rotation 180) The direction of the degree). However, the configuration is not limited to this, and the rubbing treatment direction 26a of the alignment film 12b and the rubbing treatment direction 41a of the alignment film 32a may be formed at an angle of 90 degrees.

In the above-described embodiment, the liquid crystal molecules located at the upper and lower positions corresponding to the liquid crystal layer 20 and the liquid crystal layer 40 are aligned with each other by canceling (compensating with each other) the phase difference. However, the configuration is not limited to this, and even in the case where the arrangement of the liquid crystal molecules is not completely canceled by the phase difference, it is possible to maintain high visual confirmation by switching between the negative display and the positive display.

In the above embodiment, the transparent electrodes 13a and 13b are formed by holding a part of the liquid crystal layer 20 and are subjected to voltage application control, for example, the outer peripheral portion 101, the patterns 102, 103, and 104 located above the transparent electrodes 13a and 13b. At least a portion of the switch can also perform a negative display and a positive display.

Next, another liquid crystal display device 50 relating to the present invention will be described with reference to FIG. Further, the liquid crystal display device 50 shown in Fig. 8 differs from the liquid crystal display device 1 shown in Figs. 1 and 2 described above only in that the compensation liquid crystal cell 10 is used instead of the inversion control liquid crystal cell 10, and The constituent elements of the compensating liquid crystal cell 10 are the same as those of the inverting control liquid crystal cell 10, and the same components are denoted by the same reference numerals, and their description will be omitted.

The compensation liquid crystal cells 10 are formed in a flat shape by the substrate 11, the alignment films 12a and 12b, the sealing member 14, and the liquid crystal layer 20. The liquid crystal layer 20 is composed of a twisted nematic liquid crystal material, and liquid crystal molecules having a regular alignment direction are laminated to form a layer, and have birefringence in the short axis direction and optical uniaxiality without birefringence in the long axis direction. Birefringent crystals. An optically active material having a pitch for controlling the twist of the liquid crystal molecules to the nematic liquid crystal is added to the twisted nematic liquid crystal material. Further, as the optically active material, for example, an optically active nematic liquid crystal or a cholesteric liquid crystal is used.

The compensation liquid crystal cell 10 is configured to transmit the two substrates 11 on the upper and lower sides, and the front, rear, and left and right sides of the space held by the two substrates 11 are surrounded by the sealing member 14 . The region in which the liquid crystal layer 20 is formed is formed. Further, an alignment film 12a is fixed to the top surface of the substrate 11 located below, and an alignment film 12b is fixed to the bottom surface of the substrate 11 located above.

Next, an assembly configuration of the liquid crystal display device 50 including the compensation liquid crystal cell 10 and the display liquid crystal cell 30 having the above configuration will be described.

In a state in which the liquid crystal cell 30 is fixedly displayed on the top surface of the compensation liquid crystal cell 10, the above two fixed liquid crystal cells are held by the lower polarizing plate 4 from above by the lower polarizing plate 4. At this time, as shown in FIG. 2, the transmission axis direction 3a of the lower polarizing plate 3 is slightly the same as the rubbing treatment direction 21a (the alignment direction of the liquid crystal molecules 21) of the alignment film 12a, and the transmission axis direction 4a of the upper polarizing plate 4 is also obtained. The rubbing treatment direction 46a (the alignment direction of the liquid crystal molecules 46) of the alignment film 32b is rotated by 90 degrees. Further, the rubbing treatment direction 26a of the alignment film 12b (the alignment direction of the liquid crystal molecules 26) and the rubbing treatment direction 41a (the alignment direction of the liquid crystal molecules 41) of the alignment film 32a are parallel to each other and opposite directions (direction rotated by 180 degrees). Composition.

Further, the pretilt angles θ1 and θ4, the pretilt angles θ2 and θ3 are at substantially the same angle, and the liquid crystal molecules 22 and 45, the liquid crystal molecules 23 and 44, the liquid crystal molecules 24 and 43, and the liquid crystal molecules 25 and 42 each have slightly the same inclination angle. . Further, the backlight 2 is disposed below the lower polarizing plate 3, and the illumination light irradiated by the backlight 2 is configured to illuminate the compensating liquid crystal cell 10 and the display liquid crystal cell 30 (from the lower side upward).

Next, a description will be given of a display method using the liquid crystal display device 50 described above. When the illumination light from the backlight 2 is incident by the lower polarizing plate 3 and penetrated by the upper polarizing plate 4, the portion of the liquid crystal display device 50 is brightly displayed, and the portion of the illumination light that is not penetrated by the upper polarizing plate 4 becomes dark in the dark. A state that is not displayed (no display). For example, a transparent electrode 100 configured by displaying numbers 1 to 9 can be used for the case of displaying the number 1. In the display liquid crystal cell 30 having the above configuration, seven patterns 102, 103, 104, ... as shown in Fig. 7 and a pair of transparent electrodes 100 having the outer peripheral portion 101 are used. The pair of transparent electrodes 100 are fixed in pairs between the substrate 31 located below and the alignment film 32a and between the substrate 31 located above and the alignment film 32b. Further, each of the patterns corresponding to the upper and lower sides (for example, the upper and lower patterns 102) is electrically connected to the alternating current power source 36.

With the above configuration, only voltage is applied to the portions of the patterns 102 and 103, and only the portions 102 and 103 of the illumination light are transmitted, and the digital 1 is brightly displayed. On the other hand, the other patterns 104 including the outer peripheral portion 101 partially illuminate the light without being penetrated but are displayed dark. In other words, the pattern portion that is intended to be brightly displayed is applied by applying only a voltage, and the illumination light is transmitted to perform a desired display. Therefore, in the following, the state in which the illumination light is transmitted by the upper polarizing plate 4, the state in which the illumination light is not penetrated by the upper polarizing plate 4, and the state in which the illumination light of the upper polarizing plate 4 is penetrated in the oblique direction are divided into three states. To illustrate.

First, the state in which the illumination light 2b is penetrated by the upper polarizing plate 4 will be described. Here, the illumination light 2b is penetrated by the upper polarizing plate 4 so that the voltage is applied to the transparent electrodes 35a and 35b by the AC power source 36 (the portions of the patterns 102 and 103 in the above example). The tilt state in the right and left vertical directions of the liquid crystal molecules 41 to 46 when the transparent electrodes 35a and 35b are applied with a voltage is shown in Fig. 6(a). As shown in Fig. 6(a), the liquid crystal molecules 41, 42, 45, 46 in the vicinity of the alignment films 32a and 32b are fixed to the alignment films 32a and 32b by the rubbing treatment of the alignment films 32a and 32b, before and after the voltage application. The tilt angle does not change. On the other hand, the liquid crystal molecules 43 and 44 in the intermediate portion are arranged along the long axis in the vertical direction along the electric power lines generated between the transparent electrodes 35a and 35b.

At this time, the illumination light 2b irradiated by the backlight 2 becomes circularly polarized light 2d in the plane perpendicular to the traveling direction (up-and-down direction) as shown in FIG. 9, but only by the transmission of the lower polarizing plate 3 to the transmission axis direction 3a. Parallel linearly polarized light is incident on the compensating liquid crystal cell 10. The illumination light incident on the compensation liquid crystal cell 10 travels from the lower side upward by the optical rotation of the liquid crystal molecules in the liquid crystal layer 20, and the twist angle of the liquid crystal molecules 21 to 26 (the long-axis direction of the liquid crystal molecules 21 to 26) The direction of polarization is changed, and the direction of polarization is changed by 90 degrees in the front-rear and left-right directions, and the compensation liquid crystal cell 10 is emitted as the polarization direction in the direction of the arrow 26a, and is incident on the display liquid crystal cell 30.

At this time, as shown in the above-mentioned Fig. 6(a), the liquid crystal molecules in the liquid crystal layer 40 have a long axis, and the liquid crystal molecules in the liquid crystal layer 40 have birefringence in the short axis direction. Optically uniaxial birefringent crystals having no birefringence in the long axis direction. Therefore, the illumination light 2b traveling in the liquid crystal layer 40 is not affected by the birefringence of the liquid crystal molecules, and travels along the long axis direction of the liquid crystal molecules in the liquid crystal layer 40, and the polarization direction does not change to reach the upper polarizing plate 4. . At this time, the polarization direction of the illumination light 2b reaching the upper polarizing plate 4 is the direction indicated by the arrow 41a, and the arrow 41a is parallel to the transmission axis direction 4a of the upper polarizing plate 4, so that the illumination light 2b penetrates the upper polarizing plate 4, and when When the liquid crystal display device 50 is viewed from above the upper polarizing plate 4, a bright display can be seen.

Next, a description will be given of a state in which the illumination light is not penetrated by the upper polarizing plate 4. Here, the illumination light is not penetrated by the upper polarizing plate 4 to the case where the illumination light travels to the transparent electrodes 35a, 35b which are not applied with the voltage by the AC power source 36 (the portion of the pattern 104 in the above example), and the illumination light travels. In the case of the transparent electrodes 33a and 33b (in the above-described example, the portion of the outer peripheral portion 101). In the following description, when the illumination light 2a penetrates the transparent electrodes 33a and 33b, the illumination light 2a shown in Fig. 8 travels in the compensation liquid crystal cell 10 in the same manner as the illumination light 2b described above.

Further, the compensating liquid crystal cell 10 is emitted, and the illumination light 2a incident on the display liquid crystal cell 30 travels from the lower side upward by the optical rotation of the liquid crystal molecules in the liquid crystal layer 40, and is caused to be twisted along the liquid crystal molecules 41 to 46. (the long-axis direction of the liquid crystal molecules 41 to 46), which rotates counterclockwise in the front-rear and left-right directions and changes the polarization direction by 90 degrees to reach the upper polarizing plate 4. The polarization direction of the illumination light 2a reaching the upper polarizing plate 4 is a direction indicated by an arrow 46a, and is a positional relationship in which the arrow 46a is orthogonal to the transmission axis direction 4a of the upper polarizing plate 4, so that the illumination light 2a cannot penetrate the upper polarized light. The board 4 is darkly displayed (no display) when the liquid crystal display device 50 is viewed from above the upper polarizing plate 4. Further, the same applies to the case where the illumination light travels to the transparent electrodes 35a and 35b which are not applied with the voltage by the AC power source 36, and the illumination light cannot be transmitted through the upper polarizing plate 4 to be displayed darkly (no display).

Next, the state of the illumination light that penetrates the upper polarizing plate 4 as seen from the oblique direction will be described. This is a case where the liquid crystal display device 50 is viewed obliquely from above, and the oblique illumination light 2c of the upper polarizing plate 4 shown by the arrow of the two-dot chain line in Fig. 8 is seen. The oblique illumination light 2c is an illumination light that obliquely penetrates the display liquid crystal cell 30 in a state where a voltage is applied to the transparent electrodes 35a and 35b by the AC power source 36. Here, the oblique illumination light 2c irradiated by the backlight 2 shown in FIG. 8 travels obliquely upward to compensate the liquid crystal cell 10, and the short-axis direction of the liquid crystal molecules in the liquid crystal layer 20 or the light penetrating obliquely is A phase difference is caused by the influence of birefringence. That is, as shown in Fig. 5(b), the liquid crystal molecules 21 to 26 have an inherent inclination angle in the left and right vertical directions, respectively, and the oblique illumination light 2c is affected by the birefringence due to the penetration compensation liquid crystal cell 10 and generates a phase difference. In the state of the polarizing direction, the direction of the arrow 26a is emitted from the compensating liquid crystal cell 10.

Further, the oblique illumination light 2c emitted from the compensation liquid crystal cell 10 travels in the display liquid crystal cell 30 in the direction of the arrow 41a as the polarization direction. At this time, the liquid crystal molecules in the liquid crystal layer 40 are in a state shown in Fig. 6(a) by applying a voltage. Further, the liquid crystal molecules 21 and 46, the liquid crystal molecules 22 and 45, the liquid crystal molecules 25 and 42, and the liquid crystal molecules 26 and 41 respectively compensate each other (compensate each other) in the positional relationship of the above-described phase difference. As shown in Fig. 4 (a) and Fig. 4 (b), the liquid crystal molecules in the mutually compensated positional relationship are aligned directions which are opposite to each other (direction rotated by 180 degrees), and as shown in Fig. 5 (a) And as shown in Fig. 5(b), the tilt directions are opposite in the left and right vertical directions, and the tilt angles are slightly the same. Therefore, when the oblique illumination light 2c travels, for example, to the liquid crystal molecules 46, a phase difference completely opposite to the phase difference generated in the liquid crystal molecules 21 is given, so that the phase difference generated in the liquid crystal molecules 21 is canceled. Similarly, in the other mutually compensated positional relationship liquid crystal molecules, the phase difference generated by the oblique illumination light 2c in the compensation liquid crystal cell 10 is canceled by the phase difference generated in the display liquid crystal cell 30.

Further, the oblique illumination light 2c does not undergo the influence of the birefringence of the liquid crystal molecules and travels in the display liquid crystal cell 30 along the long axis direction of the liquid crystal molecules. At this time, the phase difference generated by the liquid crystal molecules in the vicinity of the alignment films 32a and 32b is canceled by the phase difference generated by the compensation liquid crystal cell 10, and the polarization direction does not change to reach the upper polarizing plate 4. Therefore, the oblique illumination light 2 reaching the upper polarizing plate 4 has no phase difference, the polarization direction thereof is the direction indicated by the arrow 41a, and the arrow 41a is parallel to the transmission axis direction 4a of the upper polarizing plate 4, so that the oblique illumination light 2c penetrates. Polarizing plate 4. Therefore, even when viewed from obliquely above, the liquid crystal display device 50 Also shown brightly. Further, since the oblique illumination light 2c penetrating the upper polarizing plate 4 does not have a phase difference as described above, the color tone does not change as compared with the case where the illumination light 2b is viewed, and no color tone can be seen regardless of the direction in which the liquid crystal display device 50 is viewed. The display of the change.

Here, for the simplification of the effect of the liquid crystal display device 50 according to the present invention, the liquid crystal molecules which are obliquely traveled to the upper and lower positions of the corresponding liquid crystal layer 20 and the liquid crystal layer 40 are obliquely inclined to each other as described above. The illumination light 2c causes the liquid crystal alignments to cancel each other out of phase difference. Here, in particular, a configuration is adopted in which the oblique illumination light 2c is given to the phase generated in the liquid crystal layer 20 in the liquid crystal layer 40 by paying attention to and aligning the alignment direction and the tilt angle (pretilt angle) of the liquid crystal molecules. The phase difference is completely opposite, so that the phase difference generated in the liquid crystal layer 20 is cancelled. Therefore, the illumination light 2c emitted from the liquid crystal display device 50 does not have a phase difference, that is, the display of the colorless change can be performed in comparison with the illumination light 2b that travels straight. In other words, the viewing angle of the liquid crystal display device 50 can be increased.

Secondly, even in the case where the liquid crystal layer 40 and the liquid crystal layer 20 are subjected to temperature changes in the two liquid crystal layers (two liquid crystal molecules), by adding an optically active material which slightly maintains the twist pitch of the two liquid crystal molecules, even In the case where the temperature changes of the two liquid crystal molecules, the twist pitch of the liquid crystal molecules is also kept slightly the same. Therefore, even in the case where temperature changes occur in the two liquid crystal layers, the oblique illumination light 2c which travels obliquely can maintain the alignment of the liquid crystal molecules which cancel each other out of the above phase difference. For example, when the liquid crystal display device 50 is disposed in a narrow space where temperature changes are likely to occur, the liquid crystal display device 50 does not easily cause a change in color tone, and a wide viewing angle can be maintained.

In the above-described embodiment, the illumination light generated in the backlight 2 is first incident on the compensation liquid crystal cell 10, and the illumination light emitted from the compensation liquid crystal cell 10 is incident on the display liquid crystal cell 30, but may be as follows. : The order is changed. First, after the illumination light is incident on the display liquid crystal cell 30, the illumination light emitted from the display liquid crystal cell 30 is incident on the compensation liquid crystal cell 10.

In the above-described embodiment, the liquid crystal molecules constituting the liquid crystal layer 20 compensating for the liquid crystal cell 10 are rotated clockwise by 90 degrees in the alignment direction in the front-rear and left-right directions. On the other hand, the liquid crystal molecules constituting the liquid crystal layer 40 of the liquid crystal cell 30 are rotated counterclockwise by 90 degrees in the front-rear and left-right directions. Here, the twist direction (rotation direction) of the liquid crystal molecules is not limited to the above-described direction, and may be configured such that the alignment direction of the liquid crystal molecules of the liquid crystal layer 20 is rotated counterclockwise by 90 degrees to cause liquid crystal molecules of the liquid crystal layer 40. The alignment direction is rotated 90 degrees clockwise.

In the above-described embodiment, only the transparent electrode is assembled to display the liquid crystal cell 30, but the configuration is not limited thereto. For example, the transparent electrode is assembled by displaying both the liquid crystal cell 30 and the compensation liquid crystal cell 10, and the above Comparing the situation of the embodiment, it can display twice the information.

In the above embodiment, although it is displayed as a light and dark display (black and white display), color can be formed by inserting a color filter between the alignment films 32a and 32b of the liquid crystal cell 30 and the transparent electrodes. display.

In the above-described embodiment, although the alignment film 32a, 32b, 12a, and 12b are assembled in the liquid crystal cell 30 and the compensation liquid crystal cell 10, and the liquid crystal molecules have a pretilt angle (2 to 10 degrees), it is not limited to this configuration. For example, a liquid crystal molecule may have a configuration without a pretilt angle (pretilt angle is 0 degree).

In general, a display method of a liquid crystal display device includes a segment display and a dot matrix display. The liquid crystal display device 50 according to the present invention is configured by using a segment display, and the hue change is remarkably obtained. And the effect of the invention with a wide viewing angle.

In the above-described embodiment, the retardation film may be attached to one side of the upper polarizing plate 4 and one side of the lower polarizing plate 3 or one side of one of the upper polarizing plate 4 and the lower polarizing plate 3. .

1, 50, 200. . . Liquid crystal display device

2. . . Backlight

2a, 2b, 2d. . . Illumination light

2c. . . Oblique illumination

2e. . . Circular polarization

3. . . Lower polarizer

4. . . Upper polarizer

10. . . Reverse control of liquid crystal cell (lower liquid crystal cell)

11. . . Substrate (lower substrate)

12a, 12b. . . Orientation film

13a, 13b. . . Transparent electrode (lower electrode)

14, 34, 234. . . Sealing member

16. . . AC power

17. . . Toggle switch

20. . . Liquid crystal layer (lower liquid crystal layer)

21 to 26. . . Liquid crystal molecule

26a. . . Friction processing direction of the alignment film 12b

30. . . Display liquid crystal cell (upper liquid crystal cell)

31. . . Substrate (upper substrate)

32a, 32b. . . Orientation film

33a, 33b, 35a, 35b. . . Transparent electrode

34. . . Sealing member

36. . . AC power

40. . . Liquid crystal layer (upper liquid crystal layer)

41 to 46. . . Liquid crystal molecule

41a to 46a. . . arrow

60. . . Liquid crystal compensation cell

100. . . Transparent electrode (upper electrode)

101. . . Outer peripheral part (all electrodes)

102, 103, 104. . . Pattern (pattern electrode)

202. . . Backlight

202a, 202b. . . Illumination light

202c. . . Oblique illumination

203, 204. . . Polarizer

203a, 204a. . . Transmission axis direction

230. . . Liquid crystal cell

231. . . Substrate

232. . . Orientation film

233, 235. . . Transparent electrode

234. . . Sealing member

236. . . AC power

240. . . Liquid crystal layer

241, 246. . . arrow

Θ1 to θ4. . . Pretilt angle

Fig. 1 is a side sectional view showing a liquid crystal display device (negative display) relating to the present invention.

Fig. 2 is a side sectional view showing a liquid crystal display device (shown in the front view) relating to the present invention.

Fig. 3 is a schematic view showing an alignment direction of a liquid crystal display device according to the present invention.

Fig. 4(a) is a schematic view showing an alignment direction of liquid crystals in a liquid crystal cell, and Fig. 4(b) is a schematic view showing an alignment direction of liquid crystals in a liquid crystal cell in reverse rotation control.

Fig. 5(a) is a schematic view showing the tilt direction of the liquid crystal in the liquid crystal cell, and Fig. 5(b) is a schematic view showing the tilt direction of the liquid crystal in the liquid crystal cell in the reverse direction control.

Fig. 6(a) is a schematic view showing the oblique direction of the liquid crystal in the liquid crystal cell at the time of voltage application, and Fig. 6(b) is a schematic view showing the tilt direction of the liquid crystal in the liquid crystal cell during the reverse voltage control.

Fig. 7 is a plan view showing an example of a transparent electrode.

Fig. 8 is a side sectional view showing another liquid crystal display device (tone change compensation) relating to the present invention.

Fig. 9 is a schematic view showing the alignment direction of another liquid crystal display device relating to the present invention.

Fig. 10 is a side sectional view showing a conventional liquid crystal display device.

Fig. 11 is a schematic view showing the alignment direction of a conventional liquid crystal display device.

1. . . Liquid crystal display device

2. . . Backlight

2a, 2b. . . Illumination light

3. . . Lower polarizer

4. . . Upper polarizer

10. . . Reverse control of liquid crystal cell (lower liquid crystal cell)

11. . . Substrate (lower substrate)

12a, 12b. . . Orientation film

13a, 13b. . . Transparent electrode (lower electrode)

14. . . Sealing member

16. . . AC power

17. . . Toggle switch

20. . . Liquid crystal layer (lower liquid crystal layer)

30. . . Display liquid crystal cell (upper liquid crystal cell)

31. . . Substrate (upper substrate)

32a, 32b. . . Orientation film

33a, 33b, 35a, 35b. . . Transparent electrode

34. . . Sealing member

36. . . AC power

40. . . Liquid crystal layer (upper liquid crystal layer)

Claims (8)

A liquid crystal display device comprising: an upper liquid crystal cell; an upper substrate which is disposed in parallel with each other; and a pair of flat transparent upper electrodes which are arranged in parallel with the upper substrate between the upper substrate and the one The upper liquid crystal layer is formed by enclosing a layered upper liquid crystal layer; and the lower liquid crystal cell is a flat substrate arranged in parallel with each other and a flat plate disposed parallel to the lower substrate between the lower substrate a pair of transparent lower electrodes and a lower liquid crystal layer sealed in a layered shape between the pair of lower electrodes, and are joined to the bottom surface of the upper liquid crystal cell, and are characterized in that the upper liquid crystal layer is formed The upper liquid crystal molecules are twisted in a first twist direction along a spiral axis parallel to a normal line of the upper substrate and are located in a first twist direction, and the lower liquid crystal molecules constituting the lower liquid crystal layer are parallel to the lower side The spiral axis of the normal of the side substrate is twisted in the second twisting direction and is located in the second twisting direction, and the pretilt angle of the upper liquid crystal molecule is located near the upper end of the upper liquid crystal layer. The pretilt angle of the lower liquid crystal molecules in the vicinity of the lower end of the lower liquid crystal layer has an opposite direction and a slightly equal angle, and a pretilt angle of the upper liquid crystal molecule located near the lower end of the upper liquid crystal layer and the lower liquid crystal layer The pretilt angle of the lower liquid crystal molecules near the upper end has an angle in the opposite direction and slightly the same size, and the electric power of one of the pair of upper electrodes and the pair of lower electrodes The pole electrode has a plurality of pattern electrodes forming a desired pattern among the entire electrodes forming the entire display region, and the other one of the pair of upper electrodes and the pair of lower electrodes holds at least a portion of the upper liquid crystal molecules or At least a part of the lower liquid crystal molecules are displayed on the entire display area displayed by bright display or dark display by applying a voltage to control each of the plurality of pattern electrodes, and displaying the light and dark display opposite to the entire display area The desired pattern is such that an alignment direction of at least a portion of the upper liquid crystal molecules or an alignment direction of at least a portion of the lower liquid crystal molecules is changed to a direction parallel to a normal to the upper substrate by applying a voltage to the other electrode. Or parallel to the direction of the normal of the lower substrate, the light and dark display of at least a portion of the entire display area and at least a portion of the desired pattern is reversed. The liquid crystal display device of claim 1, wherein the first twisting direction and the second twisting direction are opposite directions, a twist angle toward the first twisting direction of the upper liquid crystal molecules, and a liquid crystal molecule toward the lower side The twist angle of the second twisting direction is 90 degrees or more and less than 180 degrees. The liquid crystal display device of claim 1, wherein the alignment direction of the upper liquid crystal molecules in the vicinity of the lower end of the upper liquid crystal layer and the lower liquid crystal molecules in the vicinity of the upper end of the lower liquid crystal layer The alignment direction is 90 degrees or 180 degrees in the opposite direction. A liquid crystal display device as claimed in claim 1 or 2, The pair of upper electrodes and the pair of lower electrodes are formed using a transparent electrode such as ITO. A liquid crystal display device comprising: a pair of transparent liquid crystal cells, a pair of transparent upper substrates arranged in parallel with each other; and an upper liquid crystal layer sealed in a layered shape between the pair of upper substrates; The liquid crystal cell is composed of a pair of transparent lower substrates arranged in parallel with each other and a lower liquid crystal layer sealed in a layer between the pair of lower substrates, and is bonded and disposed on the bottom surface of the upper liquid crystal cell The upper polarizing plate penetrates the linear polarized light of the predetermined transmission axis direction and is joined to the top surface of the upper liquid crystal cell; and the lower polarizing plate penetrates the linear polarized light of the predetermined transmission axis direction and is engaged The bottom surface of the lower liquid crystal cell is characterized in that the upper liquid crystal molecules constituting the upper liquid crystal layer are twisted in the first twist direction along the spiral axis parallel to the normal line of the upper substrate and are located in the first twist direction, and The lower liquid crystal molecules constituting the lower liquid crystal layer are twisted in the second twist direction along the spiral axis parallel to the normal line of the lower substrate and are located in the second twist direction. a twisting direction and the second twisting direction are opposite directions, and a pretilt angle of the upper liquid crystal molecules located near an upper end of the upper liquid crystal layer and a pretilt angle of the lower liquid crystal molecules located near a lower end of the lower liquid crystal layer are opposite a direction and a slightly equal angle, a pretilt angle of the upper liquid crystal molecule located near a lower end of the upper liquid crystal layer and the lower side liquid located near an upper end of the lower liquid crystal layer The pretilt angle of the crystal molecules has an opposite direction and a slightly equal angle, and an alignment direction of the upper liquid crystal molecules located near the lower end of the upper liquid crystal layer and an alignment direction of the lower liquid crystal molecules located near the upper end of the lower liquid crystal layer The opposite direction is 180 degrees. The liquid crystal display device of claim 5, wherein a twist angle of the first twist direction toward the upper liquid crystal molecule and a twist angle toward the second twist direction of the lower liquid crystal molecule are 90 degrees or 90 degrees Above and less than 180 degrees. The liquid crystal display device of claim 5 or 6, wherein the upper liquid crystal molecules and the lower liquid crystal molecules are composed of twisted nematic liquid crystals having the same birefringence property. The liquid crystal display device of claim 5, wherein the predetermined transmission axis direction of the upper polarizing plate and the alignment direction of the upper liquid crystal molecules in the vicinity of the upper end of the upper liquid crystal layer, and the lower polarized light The predetermined transmission axis direction of the plate is slightly parallel to at least one of the alignment directions of the lower liquid crystal molecules located near the lower end of the lower liquid crystal layer.