WO2007139196A1

WO2007139196A1 - Display device and view angle control element used for same

Info

Publication number: WO2007139196A1
Application number: PCT/JP2007/061124
Authority: WO
Inventors: Yusuke Kimura; Kimitaka Nomura; Kohji Yabuta; Ryoh Kikuchi
Original assignee: Sharp Kabushiki Kaisha
Priority date: 2006-05-31
Filing date: 2007-05-31
Publication date: 2007-12-06

Abstract

A liquid crystal panel (2) for controlling view angles is arranged at least on the rear plane or the front plane of a liquid crystal panel (1) for display. The liquid crystal panel (2) is provided with a liquid crystal cell (20) wherein liquid crystal is hybrid-oriented between oriented films (23a, 23b) arranged on a pair of light transmitting substrates (21a, 21b), respectively, and a drive circuit (27) for applying a voltage to a liquid crystal layer (24) of a liquid crystal cell (20). The liquid crystal cell (20) is arranged between two polarization plates (25, 26) arranged to have polarization axes in parallel. The drive circuit (27) switches the display status to and from a wide viewing angle and a narrow viewing angle by changing the arrangement of the liquid crystal molecules of the liquid crystal layer (24) of the liquid crystal panel (2).

Description

Specification

Display device and viewing angle control element used therefor

Technical field

[0001] The present invention provides a viewing angle control element capable of switching the viewing angle of a display device between a wide viewing angle and a narrow viewing angle, and a display device capable of controlling the viewing angle by using the viewing angle control element. It is related.

Background art

[0002] Conventionally, a display device is generally required to have as wide a viewing angle as possible so that a clear image can be seen at any viewing angle force. In particular, liquid crystal display devices that have become widespread recently have been developed in various technologies to achieve a wide viewing angle because the liquid crystal itself has a viewing angle dependency. However, depending on the usage environment, it may be advantageous to have a narrow viewing angle so that only the user can see the displayed content. In particular, notebook personal computers, personal digital assistants (PDAs), mobile phones, etc. are highly likely to be used in places where an unspecified number of people can exist such as in trains. In such a usage environment, it is desirable that the viewing angle of the display device be narrow because it is not desirable for others in the vicinity to view the display content from the viewpoint of confidentiality and privacy protection. Thus, in recent years, there has been an increasing demand for switching the viewing angle of one display device between a wide viewing angle and a narrow viewing angle depending on the usage situation. This requirement is not limited to the liquid crystal display device, but is a common problem with any display device.

[0003] To deal with such problems, conventionally, a wide viewing angle mode in which the display image on the main display can be viewed from any direction in addition to the main display for displaying an image, and the main display only from a specific direction. A display device including a switch liquid crystal display that can be electrically switched to a narrow viewing angle mode in which a display image on the display can be visually recognized has been proposed (for example, Patent Document 1 below).

[0004] This switch liquid crystal display has a liquid crystal layer of homogeneous alignment. A pair of polarizing plates is provided across the liquid crystal layer, and the liquid crystal molecules of the liquid crystal layer are uniaxially aligned so that the major axis direction is substantially parallel to the polarization transmission axis of the pair of polarizing plates. And switch If no voltage is applied to the liquid crystal display, the major axis direction of the liquid crystal molecules is parallel to the substrate surface, and the incident light is transmitted through the polarizing plate without being affected by the birefringence of the liquid crystal molecules from any direction. Thus, the wide viewing angle mode is set. In addition, when a voltage is applied to the switch liquid crystal display so that the major axis direction of the liquid crystal molecules is tilted with respect to the substrate surface, the birefringence of the liquid crystal is observed when viewed from other than the front direction. As a result, light is not transmitted through the switch liquid crystal display and the narrow viewing angle mode described above is entered.

FIG. 22 is a graph showing transmittance characteristics when the switch liquid crystal display disclosed in Patent Document 1 is set to a narrow viewing angle mode. Note that the elevation angle is the angle between the observer's viewpoint and the normal of the line force display that connects the center of the display surface of the display. As shown in FIG. 22, the conventional switch liquid crystal display shows the maximum transmittance at an elevation angle of 0 °, and the transmittance decreases as the elevation angle increases. In other words, in the narrow viewing angle mode, the display on the main display can be clearly seen when observing the force in the front direction, but the transmittance of the switch liquid crystal display is reduced when observing the force in the oblique direction. I ca n’t see the display.

Patent Document 1: Japanese Unexamined Patent Publication No. 2006-64882

Disclosure of the invention

Problems to be solved by the invention

However, as can be seen from FIG. 22, in the conventional configuration disclosed in Patent Document 1, in the narrow viewing angle mode, the elevation angle becomes larger than 0 degree and the transmittance decreases. There is a tendency for the transmittance to rise again after the force transmittance reaches the minimum value (approximately 1%) (this phenomenon is hereinafter referred to as “pounding”). The degree of pounding is particularly noticeable when the retardation value of the liquid crystal is large.

Accordingly, in the conventional configuration disclosed in Patent Document 1 described above, as shown in FIG. 23, when the switch liquid crystal display 91 is set to the narrow viewing angle mode, a relatively narrow viewing angle range centering on the front direction is provided. When viewed from A, the display on the main display 92 is visible. Then, the display on the main display 92 is shielded when observed from the viewing angle ranges Bl and B2 having an elevation angle larger than the viewing angle range A. In addition, in the viewing angle ranges CI and C2, where the elevation angle is larger than the viewing angle range Bl and B2, the display on the main display 92 can be visually recognized by the pounding. The phenomenon of being able to occur sometimes occurred. In other words, the conventional configuration described above has a problem that display shielding for a viewpoint with a large elevation angle (viewing angle range CI, C2) is not always sufficient.

[0008] In view of the above problems, the present invention provides a viewing angle control element capable of narrowing the range of the elevation angle at which the display of the display element can be seen in the narrow viewing angle mode, and a table provided with the viewing angle control element. An object is to provide a display device.

Means for solving the problem

In order to achieve the above object, a display device according to the present invention is disposed on a display element driven according to an image to be displayed, and at least one of a back surface and a front surface of the display element, A display device comprising a viewing angle control element that controls a viewing angle of the display element, wherein the viewing angle control element is provided on each of a pair of translucent substrates and the translucent substrate. A liquid crystal cell having a vertical alignment film and a horizontal alignment film; a hybrid alignment liquid crystal layer sandwiched between the vertical alignment film and the horizontal alignment film; and a drive circuit for applying a voltage to the liquid crystal layer. In the display device, the cell is disposed between two polarizing plates whose polarization transmission axes are disposed substantially in parallel, and the alignment state of the liquid crystal molecules in the liquid crystal layer of the viewing angle control element is applied by applying a voltage from the driving circuit. To change The first state providing the first viewing angle range and the second providing the second viewing angle range within the first viewing angle range and narrower than the first viewing angle range. It is possible to switch between these states.

[0010] According to this configuration, when the liquid crystal layer of the viewing angle control element is in a hybrid orientation, when the second state (narrow viewing angle) is set, the transmittance of viewing force with a relatively high elevation angle is high. It is possible to suppress the occurrence of the pounding phenomenon. Thereby, in the narrow viewing angle mode, it is possible to provide a display device capable of narrowing the range of the elevation angle at which the display of the display element can be seen from the conventional one.

[0011] In the display device according to the present invention, the driving circuit does not apply a voltage to the liquid crystal layer of the viewing angle control element, so that the first state is established, and the driving circuit enters the liquid crystal layer of the viewing angle control element. It is preferable that the second state is achieved by applying a predetermined voltage. [0012] In the display device according to the present invention, it is preferable that a negative C plate is provided at least at one position between the liquid crystal cell and the two polarizing plates. The negative C plate is a retardation film in which the relationship of Nx = Ny> Nz is established when the refractive index in the plane direction is Nx, Ny and the refractive index in the thickness direction is Nz. By providing the negative C plate, elliptically polarized light generated by birefringence of the liquid crystal layer of the viewing angle control element was optically compensated, and in the first state (wide viewing angle), a viewing angle force with a relatively large elevation angle was observed. In addition to preventing coloration, the viewing angle can be further widened.

[0013] In addition, in the configuration including the negative C plate, the driving circuit applies the predetermined voltage V to the liquid crystal layer of the viewing angle control element, so that the second state is achieved.

2

The drive circuit applies a predetermined voltage greater than the predetermined voltage V to the liquid crystal layer of the viewing angle control element.

2

It is preferable that the first state is achieved by applying the voltage V. In addition, the predetermined power

1

The pressure V is a voltage that causes liquid crystal molecules in the liquid crystal layer of the viewing angle control element to be home-orientated.

1

The pressure value is preferable.

In the display device according to the present invention, the display element is a display element that emits linearly polarized light, and one of the two polarizing plates is a polarizing plate provided on the display element. It can be configured.

In the display device according to the present invention, the display element may be a transmissive liquid crystal display element, and may further include a backlight. In this case, the viewing angle control element may be arranged between the backlight and the transmissive liquid crystal display element, or the viewing angle control element may be disposed on the front surface of the transmissive liquid crystal display element. An arrangement may be adopted.

[0016] The display device according to the present invention may be configured such that the display element is a reflective liquid crystal display element or a transflective liquid crystal display element. Alternatively, the display element may be a self-luminous display element.

In the display device according to the present invention, the retardation of the liquid crystal layer of the viewing angle control element is in the range of 600 nm to 2500 nm, and the pretilt angle on the horizontal alignment film side is in the range of 1 ° to 20 °. The pretilt angle on the vertical alignment film side is preferably in the range of 70 ° to 90 °. If the pretilt angle is set within this range, the second state (narrow viewing angle) is established. In this case, the elevation angle is relatively large and the display shielding performance with respect to the viewing angle can be sufficiently secured.

[0018] In the display device according to the present invention, the retardation of the liquid crystal layer of the viewing angle control element is in the range of 600 nm to 2500 nm, and the pretilt angle on the horizontal alignment film side is in the range of 10 ° to 30 °. And the pretilt angle on the vertical alignment film side is preferably in the range of 75 ° to 90 °. If the pretilt angle is set within this range, the display shielding performance for a viewing angle with a relatively high elevation angle can be sufficiently secured in the second state (narrow viewing angle).

In the display device according to the present invention, the retardation of the liquid crystal layer of the viewing angle control element is in the range of 600 nm to 2500 nm, and the pretilt angular force on the horizontal alignment film side is in the range of ¾0 ° to 40 °. The pretilt angle on the vertical alignment film side is preferably in the range of 80 ° to 90 °. If the pretilt angle is set within this range, the display shielding performance for a viewing angle with a relatively high elevation angle can be sufficiently secured in the second state (narrow viewing angle).

[0020] In order to achieve the above object, the viewing angle control element according to the present invention is disposed on at least one of the back surface and the front surface of the display element driven in accordance with an image to be displayed. A viewing angle control element used for controlling a viewing angle of an element, comprising a pair of translucent substrates, a vertical alignment film and a horizontal alignment film provided on each of the translucent substrates, and the vertical alignment A liquid crystal cell having a hybrid alignment liquid crystal layer sandwiched between a film and a horizontal alignment film, a drive circuit for applying a voltage to the liquid crystal layer, and at least one polarizing plate, wherein the drive circuit includes the liquid crystal By changing the alignment state of the liquid crystal molecules in the layer, the light emission range is within the first viewing angle range and the second viewing angle range, which is narrower than the first viewing angle range. Can be switched between different viewing angle ranges The Rukoto and Features.

[0021] According to this configuration, the liquid crystal layer having the no-or-ibrid orientation is provided, whereby the transmittance from a viewing angle with a relatively high elevation angle is increased in the second state (narrow viewing angle). Occurrence of the switching phenomenon can be suppressed as compared with the conventional case. Thereby, in the narrow viewing angle mode, it is possible to provide a viewing angle control element capable of narrowing the range of the elevation angle at which the display of the display element can be seen from the conventional one.

The invention's effect

[0022] According to the present invention, the range of the elevation angle at which the display can be seen in the narrow viewing angle mode is made larger than in the conventional case. It is possible to provide a viewing angle control device that can be narrowly restricted and a display device that can effectively prevent a person from being seen by others.

Brief Description of Drawings

FIG. 1 is a schematic cross-sectional view showing a schematic configuration of a display device according to a first embodiment of the present invention.

FIG. 2 is a schematic diagram showing the relationship between the direction of rubbing treatment for the alignment film and the direction of the polarization transmission axis of the polarizing plate.

[Fig. 3] Fig. 3 (a) and Fig. 3 (b) show the alignment state of the liquid crystal molecules in the viewing angle control liquid crystal panel when the voltage applied to the liquid crystal layer is switched between OV and a predetermined voltage Va. FIG.

[FIG. 4] FIGS. 4 (a) and 4 (b) are charts showing the transmittance of the liquid crystal panel for viewing angle control when the voltage applied to the liquid crystal layer is switched between OV and a predetermined voltage Va, respectively. .

FIG. 5 is an explanatory diagram showing definitions of azimuth angle φ and elevation angle Θ.

[FIG. 6] FIG. 6 shows the case where the retardation of the liquid crystal layer of the viewing angle control liquid crystal panel is 600 nm, and the pretilt angle on the vertical alignment film side and the pretilt angle on the horizontal alignment film side are set to various values. It is explanatory drawing which shows the evaluation result of the transmittance | permeability characteristic of the liquid crystal panel for viewing angle control.

[FIG. 7] FIG. 7 shows a case where the retardation of the liquid crystal layer of the liquid crystal panel for viewing angle control is 800 nm, and the pretilt angle on the vertical alignment film side and the pretilt angle on the horizontal alignment film side are set to various values. It is explanatory drawing which shows the evaluation result of the transmittance | permeability characteristic of the liquid crystal panel for viewing angle control.

[FIG. 8] FIG. 8 shows the case where the retardation of the liquid crystal layer of the liquid crystal panel for viewing angle control is lOOOnm, and the pretilt angle on the vertical alignment film side and the pretilt angle on the horizontal alignment film side are set to various values. It is explanatory drawing which shows the evaluation result of the transmittance | permeability characteristic of the liquid crystal panel for viewing angle control.

[FIG. 9] FIG. 9 shows the case where the retardation of the liquid crystal layer of the liquid crystal panel for viewing angle control is 1300 nm, and the pretilt angle on the vertical alignment film side and the pretilt angle on the horizontal alignment film side are set to various values. It is explanatory drawing which shows the evaluation result of the transmittance | permeability characteristic of the liquid crystal panel for viewing angle control.

[FIG. 10] FIG. 10 shows the viewing angle when the retardation of the liquid crystal layer of the viewing angle control liquid crystal panel is 1500 nm and the pretilt angle on the vertical alignment film side and the pretilt angle on the horizontal alignment film side are set to various values. It is explanatory drawing which shows the evaluation result of the transmittance | permeability characteristic of the liquid crystal panel for angle control. [FIG. 11] FIG. 11 shows the viewing angle when the retardation of the liquid crystal layer of the liquid crystal panel for viewing angle control is 2500 nm and the pretilt angle on the vertical alignment film side and the pretilt angle on the horizontal alignment film side are set to various values. It is explanatory drawing which shows the evaluation result of the transmittance | permeability characteristic of the liquid crystal panel for angle control.

[FIG. 12] FIG. 12 shows that the retardation of the liquid crystal layer of the viewing angle control liquid crystal panel is 600 nm, the pretilt angle P on the horizontal alignment film side is set to 10 °, and the pretilt angle P on the vertical alignment film side is b a

FIG. 7 is a transmittance characteristic diagram of a liquid crystal panel for viewing angle control when set to 70 °, 75 °, 80 °, and 85 °, respectively.

[FIG. 13] FIG. 13 shows that the retardation of the liquid crystal layer of the viewing angle control liquid crystal panel is 600 nm, the pretilt angle P on the horizontal alignment film side is set to 20 °, and the pretilt angle P on the vertical alignment film side is b a

[FIG. 14] FIG. 14 shows that the retardation of the liquid crystal layer of the viewing angle control liquid crystal panel is 600 nm, the pretilt angle P on the horizontal alignment film side is set to 30 °, and the pretilt angle P on the vertical alignment film side is b a

FIG. 6 is a transmittance characteristic diagram of a viewing angle control liquid crystal panel when set to 70 °, 75 °, 80 °, and 85 °, respectively.

15] Figure 15 shows that the retardation of the liquid crystal layer of the liquid crystal panel for viewing angle control is 600 nm, the pretilt angle P on the horizontal alignment film side is set to 40 °, and the pretilt angle P on the vertical alignment film side is b a

FIG. 16 (a) is a schematic diagram of a liquid crystal layer in a hybrid orientation in the viewing angle control liquid crystal panel of this embodiment, and FIG. 16 (b) is a diagram of a conventional switch liquid crystal display with a homogeneous orientation. It is a schematic diagram of a liquid-crystal layer.

[FIG. 17] FIG. 17 (a) shows liquid crystal molecules that sequentially transmit light along the optical path when light passes through the liquid crystal layer shown in FIG. 16 (a) parallel to the xz plane and at an elevation angle Θ. M to M

Fig. 17 (b) shows the projection on the optical path when light is transmitted through the liquid crystal layer shown in Fig. 16 (b) parallel to the xz plane and at an elevation angle Θ. Sequentially transmits light It is a projection view when the liquid crystal molecules m to m are viewed from the optical path direction.

1 5

FIG. 18 is a schematic cross-sectional view showing a schematic configuration of a display device according to a second embodiment of the present invention.

[FIG. 19] FIGS. 19 (a) and 19 (b) show the alignment state of the liquid crystal molecules in the viewing angle control liquid crystal panel when the voltage applied to the liquid crystal layer is switched between Vb and Va, respectively. FIG.

FIG. 20 is an explanatory diagram showing a range of preferred values for the retardation of the negative C plate with respect to the retardation value of the liquid crystal layer of the viewing angle control liquid crystal panel according to the present embodiment.

[FIG. 21] FIGS. 21 (a) and 21 (b) show the viewing angle control liquid crystal panel when the voltage applied to the liquid crystal layer is switched between Vb and Va in the state where the negative C plate is laminated. It is a chart which shows each transmittance | permeability.

FIG. 22 is a graph showing the transmittance characteristics of a conventional viewing angle control device.

[FIG. 23] FIG. 23 shows a viewing angle range (A, CI, C2) where the display of the main display can be seen and a viewing angle range (Bl, B2) where the main display can be seen in a display device equipped with a conventional viewing angle control device. It is a schematic diagram which shows distribution.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, in the drawings referred to below, for convenience of explanation, among the constituent members of the embodiment of the present invention, only the main members necessary for explaining the present invention are shown in a simplified manner. Therefore, the display according to the present invention can include arbitrary components not shown in the drawings referred to in this specification. In addition, the dimensions of the members in the drawings do not faithfully represent the actual dimensions of the constituent members and the dimensional ratios of the members.

[First Embodiment]

FIG. 1 is a schematic cross-sectional view showing a schematic configuration of a display device 100 according to the first embodiment of the present invention. As shown in FIG. 1, the display device 100 includes two liquid crystal panels: a display liquid crystal panel 1 (display element) for displaying an image and a viewing angle control liquid crystal panel 2 (viewing angle control element). ing. The display liquid crystal panel 1 in the present embodiment is a transmissive type and has a display device. The device 100 includes a backlight 3 as a light source. In the present embodiment, a configuration using a liquid crystal panel as the display element is illustrated, but as will be described later, the display element applicable to the present invention is not limited to the liquid crystal panel.

[0026] In the display device 100, by switching the liquid crystal in the viewing angle control liquid crystal panel 2, the display device 100 has a wide viewing angle (wide viewing angle) in which an image on the display liquid crystal panel 1 can be viewed, and the viewing angle is The display state can be switched between a narrow state (narrow viewing angle). The narrow viewing angle is particularly suitable when others do not want to see the image on the LCD panel 1 for display, and the wide viewing angle is used for other normal use or images on the LCD panel 1 for display. It is suitable for use in situations where multiple people see it at the same time.

The liquid crystal mode and cell structure of the display liquid crystal panel 1 are arbitrary. Further, the drive mode of the display liquid crystal panel 1 is also arbitrary. That is, as the display liquid crystal panel 1, an arbitrary liquid crystal panel capable of displaying characters, images, or moving images can be used. Therefore, in the present embodiment, the detailed structure of the display liquid crystal panel 1 is not shown, and the description thereof is also omitted. Further, the display liquid crystal panel 1 may be a panel capable of color display or a panel dedicated to monochrome display. Furthermore, since any known backlight without any limitation can be used for the configuration of the backlight 3, illustration and description of the detailed structure of the backlight 3 are also omitted. When the display liquid crystal panel 1 is a reflective liquid crystal panel, no backlight is required.

The viewing angle control liquid crystal panel 2 includes a liquid crystal cell 20 having a pair of translucent substrates 21a and 21b, transparent electrodes 22a and 22b, alignment films 23a and 23b, and a liquid crystal layer 24. A pair of polarizing plates 25 and 26 disposed so as to sandwich the liquid crystal cell 20 and a drive circuit 27 for controlling the voltage between the transparent electrodes 22a and 22b are provided.

In the liquid crystal cell 20, the alignment film 23a is a vertical alignment film, and the alignment film 23b is a horizontal alignment film. That is, the liquid crystal molecules in the liquid crystal layer 24 are arranged so that the molecular major axis forms an angle of approximately 70 ° to 90 ° with respect to the interface in the vicinity of the interface with the alignment film 23a in a state where no voltage is applied. In the vicinity of the interface with the alignment film 23b, the molecular long axes are arranged so as to form an angle of approximately 0 ° to 30 ° with respect to the interface. In FIG. 1, the alignment film 23b on the display liquid crystal panel 1 side is a horizontal alignment film, and the other alignment film 23a is a vertical alignment film. However, on the contrary, the alignment film 23b on the display liquid crystal panel 1 side may be a vertical alignment film, and the alignment film 23a may be a horizontal alignment film.

The transparent electrodes 22a and 22b are formed using, for example, ITO (Indium Tin Oxide).

Since the liquid crystal panel 1 for display needs to drive the liquid crystal in display units (pixel units or segment units), the liquid crystal for controlling the viewing angle and the liquid crystal for controlling the viewing angle is required. Panel 2 has no restrictions on the electrode structure. For example, in order to perform uniform switching over the entire display surface, a uniform transparent electrode may be formed on the entire surface of the translucent substrates 21a and 21b, or a logo in the narrow viewing angle mode. Alternatively, an electrode structure that displays a unique pattern may be adopted.

[0031] Each of the alignment films 23a and 23b is rubbed. FIG. 2 is a schematic diagram showing the relationship between the direction of rubbing treatment for the alignment films 23a and 23b and the direction of the polarization transmission axis of the polarizing plates 25 and 26. FIG. In the present embodiment, the normal direction to the paper surface of FIG. 2 is the z direction, and the plane parallel to the surfaces of the alignment films 23a and 23b and the polarizing plates 25 and 26 is the xy plane. In addition, the direction parallel to the rubbing direction is defined as the y direction. As shown in FIG. 2, the directions of rubbing treatment for the alignment films 23a and 23b of the viewing angle control liquid crystal panel 2 are parallel to each other and opposite to each other (anti-parallel). However, the direction of rubbing treatment for the alignment films 23a and 23b of the viewing angle control liquid crystal panel 2 may be parallel to each other and in parallel.

Further, as shown in FIG. 2, the polarizing plates 25 and 26 are linear polarizing plates, the polarization transmission axes of which are substantially parallel, and the polarization transmission axes are rubbed with the alignment films 23a and 23b. It is arranged so as to be substantially orthogonal to the direction.

As the material of the liquid crystal layer 24, positive nematic liquid crystal is used. In the state where no voltage is applied to the liquid crystal layer 24, the liquid crystal molecules of the liquid crystal layer 24 are in the vicinity of the interface with the alignment film 23a (vertical alignment film) as shown in FIG. 3 (a). In the vicinity of the interface with the alignment film 23b (horizontal alignment film), the major axis is almost horizontal with respect to the interface, and the direction of the molecular major axis gradually changes between these interfaces. Arrange them in the same state. Note that the pretilt angle P with respect to the interface with the alignment films 23a and 23b is obtained by rubbing.

, P are generated respectively. [0034] When a predetermined voltage Va is applied to the liquid crystal layer 24 by the drive circuit 27, the liquid crystal molecules of the liquid crystal layer 24 are parallel to the rubbing direction (yz plane) as shown in FIG. Rotate to align the long axis of the molecule with the direction of the electric field. In the vicinity of the interface between the alignment films 23a and 23b, since the anchoring strength of the alignment film is large, the orientation of the liquid crystal molecules does not change so much and the pretilt angle is maintained.

In FIG. 4 (a) and FIG. 4 (b), the drive circuit 27 determines that the voltage applied to the liquid crystal layer 24 is OV (state in FIG. 3 (a)) and a predetermined voltage Va (in FIG. 3 (b)). 6 is a chart showing the transmittance of the viewing angle control liquid crystal panel 2 when the state is switched to the state). In FIGS. 4 (a) and 4 (b), the measurement was performed with the retardation of the liquid crystal layer 24 set to 1500 nm.

In the present embodiment, the viewing angle from a certain viewing point with respect to the panel surface of the viewing angle control liquid crystal panel 2 is represented by an azimuth angle φ and an elevation angle Θ with respect to the center of the panel surface. FIG. 5 is an explanatory diagram showing the definitions of the azimuth angle φ and the elevation angle Θ. As shown in Fig. 5, the azimuth angle φ is the rotation angle of the line connecting the leg of the perpendicular line from the viewpoint to the panel surface and the center of the panel surface. In the example of Fig. 5, if the panel surface is the xy plane, the azimuth angle Φ with respect to the center of the panel surface is counterclockwise when viewed from the upper side of the z-axis with the positive direction of the X-axis as 0 °. It shall increase. The elevation angle Θ is the angle between the z-axis and the line connecting the viewpoint and the center of the panel surface.

[0037] As shown in FIG. 4 (a), when no voltage is applied, the elevation angle of about 60 ° is sufficient when viewed from a viewing angle of 0 ° and 180 ° with respect to the screen of the display device 100. Since the brightness is obtained, the display content of the display liquid crystal panel 1 can be visually recognized. On the other hand, as shown in Fig. 4 (b), when the voltage Va is applied, the luminance is sufficiently high when viewed from the viewing angles of 0 ° and 1800 ° compared to when no voltage is applied as shown in Fig. 4 (a). Therefore, if the applied voltage to the liquid crystal layer 24 of the viewing angle control liquid crystal panel 2 in the display device 100 is set to 0 V, the display liquid crystal panel A wide viewing angle mode can be realized in which the display content of 1 can be viewed from a relatively wide range, and if the applied voltage is a predetermined voltage Va, the display content of the liquid crystal panel for display 1 can be viewed from the elevation angle. A narrow viewing angle mode limited to a relatively narrow range can be realized. The applied voltage Va is about 1.0V to 4.0V. [0038] Here, Figs. 6 to 11 show that the retardation of the liquid crystal layer 24 is 600, 800, lOOOnm, 1300nm, 1500nm, 2500nm, respectively. The pretilt angle P on the alignment layer) is set to 70 °, 75 °, 80 °, 85 °, and 90 °.

a

The pretilt angle P on the alignment film 23b (horizontal alignment film) side is 1 °, 3 °, 10 °, 20 °, 30 °, 4

b

The evaluation results of the transmittance characteristics of the viewing angle control liquid crystal panel 2 when set to 0 ° and 50 ° are shown. These pretilt angles can be realized by a rubbing method, an oblique deposition method, a photo-alignment method, or the like.

[0039] The circles in FIGS. 6 to 11 indicate that the pounding is suppressed as compared with the prior art and that the maximum transmittance is 10% or less even in the range where the pounding occurs. To do. In each of FIGS. 6 to 11, as a conventional technique to be compared, the conventional switch liquid crystal display with the homogenous alignment described above is used, and the retardation is shown in FIGS. 6 to 11 in the present embodiment. The viewing angle control liquid crystal panel 2 was set to the same value, and the pretilt angle was 3 °. The △ marks shown in FIGS. 6 to 11 indicate the force S in which the pounding is suppressed as compared with the prior art, and the maximum transmittance in the range where the pounding occurs slightly exceeds 10%, but the display liquid crystal panel 1 This means that the display content was low enough to be invisible. The X marks shown in FIGS. 6 to 11 mean that the casting was performed up to such a high transmittance that the display contents of the display liquid crystal panel 1 can be visually recognized.

[0040] As shown in FIG. 6, when the retardation of the liquid crystal layer 24 is 600 nm, the pretilt angle P on the horizontal alignment film side is in the range of about 1 ° to 40 ° and the pretilt angle P on the vertical alignment film side is

b

In the range of approximately 70 ° to 90 °, the transmittance is suppressed to 10% or less and good shielding is achieved.

The shielding properties were obtained.

[0041] As shown in FIG. 7, when the retardation of the liquid crystal layer 24 is 800 nm, the pretilt angle P on the vertical alignment film side is approximately 1 ° to 10 ° when the pretilt angle P on the horizontal alignment film side is approximately 1 ° to 10 °.

When b a is in the range of approximately 70 ° to 90 °, the transmittance is suppressed to approximately 10% or less, and good shielding characteristics are obtained. However, the pretilt angle P on the horizontal alignment film side is about 20 ° to 30 °.

b

In this range, the pretilt angle P on the vertical alignment film side should be in the range of approximately 75 ° to 90 °.

a

And are preferred. When the pretilt angle P on the horizontal alignment film side is approximately 40 °, The pretilt angle P on the alignment film side is preferably in the range of about 80 ° to 90 °.

a

As shown in FIG. 8, when the retardation of the liquid crystal layer 24 is lOOOnm, the pretilt angle P ba on the vertical alignment film side is about 1 ° to 10 ° when the pretilt angle P on the horizontal alignment film side is approximately 1 ° to 10 °. In the range of approximately 70 ° to 90 °, the transmittance was suppressed to approximately 10% or less, and good shielding characteristics were obtained. Also, the pretilt angle P on the horizontal alignment film side is about 20 ° to 30 ° b

When the pretilt angle P on the vertical alignment film side is approximately 75 ° to 90 °,

a

The transmittance was suppressed to about 10% or less, and good shielding properties were obtained. However, when the pretilt angle P on the horizontal alignment film side is in the range of about 40 °, the pretilt angle P ba on the vertical alignment film side is preferably in the range of about 80 ° to 90 °.

[0043] As shown in FIG. 9, when the retardation of the liquid crystal layer 24 is 1300 nm, the pretilt angle P ba on the vertical alignment film side is about 1 ° to 10 ° when the pretilt angle P on the horizontal alignment film side is in the range of about 1 ° to 10 °. The transmittance is 10 in the range of about 70 ° ~ 90 °. /. It was suppressed to a level lower than that, and generally good shielding properties were obtained. However, the pretilt angle P on the horizontal alignment film side is about 2

b

0. ~ 30. In this range, the pretilt angle P on the vertical alignment film side is approximately 75. ~ 90 °

a

It is preferable to be in the range. In addition, the pretilt angle P on the horizontal alignment film side is approximately 40 °.

The pretilt angle P on the vertical alignment film side should be approximately 80 ° to 90 °.

preferable.

As shown in FIG. 10, when the retardation of the liquid crystal layer 24 is 1500 nm, when the pretilt angle P on the horizontal alignment film side is in the range of approximately 1 ° to 10 °, the pretilt angle on the vertical alignment film side

b

When P is in the range of about 70 ° to 90 °, the transmittance is suppressed below about 10%, and a

In general, good shielding properties were obtained. However, when the pretilt angle P on the horizontal alignment film side is in the range of approximately 20 ° to 30 °, the pretilt angle P on the vertical alignment film side is approximately 75 ° to 90 ° a

It is preferable to set it as the range. In addition, the pretilt angle P on the horizontal alignment film side is approximately 40 °.

b

In the range, the pretilt angle P on the vertical alignment film side is preferably in the range of about 80 ° to 90 °.

As shown in FIG. 11, when the retardation of the liquid crystal layer 24 is 2500 nm, when the pretilt angle P on the horizontal alignment film side is in the range of approximately 1 ° to 10 °, the pretilt angle on the vertical alignment film side

b

When P is in the range of about 70 ° to 90 °, the transmittance is suppressed below about 10%. In general, good shielding properties were obtained. In addition, the pretilt angle P on the horizontal alignment film side is large.

b In the range of approximately 20 ° to 30 °, the pretilt angle P on the vertical alignment film side is approximately 75 ° to 90 °.

a

. The range of is preferable. In addition, the pretilt angle P on the horizontal alignment film side is in the range of about 40 °.

b

The pretilt angle P on the vertical alignment film side is preferably in the range of about 80 ° to 90 °.

a

That's right.

[0046] As described above, when the retardation of the liquid crystal layer 24 is 600 nm to 2500 nm, the pretilt angle on the vertical alignment film side is within the range of the pretilt angle P on the horizontal alignment film side of about 1 ° to 20 °.

b

The angle P is preferably in the range of about 70 ° to 90 °. In addition, when the pretilt angle P on the horizontal alignment film side is in the range of about 10 ° to 30 °, the pretilt angle P on the vertical alignment film side is

b a, preferably in the range of about 75 ° to 90 °. In addition, when the pretilt angle P on the horizontal alignment film side is approximately 20 ° to 40 °, the pretilt angle P on the vertical alignment film side is approximately 80 b a

. A range of ˜90 ° is preferable.

[0047] In the range examined by the inventors, the retardation of the liquid crystal layer 24 is about 1500 nm, the pretilt angle P on the horizontal alignment film side is about 3 °, and the pretilt angle on the vertical alignment film side is

b

The most favorable results were obtained when P was approximately 85 °. That is, in this case a

The angle of elevation at which the transmittance was lowest was small, and the pounding at a larger angle of elevation was small, and the transmittance at the time of pounding was low. However, the above figures are only examples, and there is a possibility that optimal results will be obtained other than these figures.

For example, in FIGS. 12 to 15, the retardation of the liquid crystal layer 24 is 600 nm, and the pretilt angle P on the alignment film 23b (horizontal alignment film) side is 10 ° (FIG. 12), 20 ° (FIG. 13), 30 ° (Fig. 14), 40 ° (

b

(Fig. 15), the pretilt angle P on the alignment film 23a (vertical alignment film) side is set to 70 °,

a

The transmittance characteristics of the liquid crystal panel 2 for viewing angle control were determined by setting each of 75 °, 80 °, and 85 °. As a comparative example, the transmittance characteristics of a conventional switch liquid crystal display with the above-described homogeneous orientation are shown. In this conventional switch liquid crystal display, the retardation is 600 nm and the pretilt angle is 3 °.

[0049] As can be seen from FIGS. 12 to 15, the liquid crystal panel 2 for controlling the viewing angle, which is effective in this embodiment, has an elevation angle larger than 0 ° when the retardation of the liquid crystal layer 24 is 600 nm. In the range where the transmittance decreases and the elevation angle exceeds approximately 35 ° to 45 °, the transmittance is reduced to 0.10. It will not be exceeded. The same applies to the conventional switch liquid crystal display shown as a comparative example in FIGS. However, in the conventional switch liquid crystal display, after the transmittance reaches the lowest value (approximately 0.01), the phenomenon that the transmittance rises again to approximately 0.09 (pounding) is seen. The viewing angle control liquid crystal panel 2 according to the present embodiment has pretilt angles P of 70 °, 75 °, 80 ° and 85 ° a

Set the pretilt angle P to 10 °, 20 °, 30 °, and 40 ° respectively.

For all combinations with the fixed case, the degree of pounding is small compared to the conventional switch LCD. Therefore, in the liquid crystal panel 2 for controlling the viewing angle, which is effective in this embodiment, the retardation of the liquid crystal layer 24 is set to 600 nm, the pretilt angle P is set to 70 ° to 90 °, and the pretilt angle P is set to 0 ° to 40 °. The elevation angle is the ratio b

It can be seen that the display contents of the display liquid crystal panel 1 can be shielded more reliably than the conventional switch liquid crystal display for a relatively large viewpoint.

As described above, according to the present embodiment, the liquid crystal layer 24 of the viewing angle control liquid crystal panel 2 is hybrid-aligned, thereby comparing with a conventional switch liquid crystal display using a homogeneously aligned liquid crystal layer. Thus, by suppressing the casting in a range where the elevation angle is relatively large, the display content of the display liquid crystal panel 1 can be shielded over a wider elevation angle range.

[0051] Here, in the viewing angle controlling liquid crystal panel 2 including the liquid crystal layer 24 having the no-or-brid orientation according to the present embodiment, the principle that the pounding in a range where the elevation angle is relatively large is suppressed will be described below. To do.

[0052] For example, in the viewing angle control liquid crystal panel 2 of the present embodiment shown in FIG. 2, as described above, the elevation angle Θ is larger than the viewing angle in the xz plane shown in FIGS. The viewing angle can be controlled according to the conditions. Here, FIG. 16 (a) is a schematic diagram of the liquid crystal layer 24 of hybrid alignment in the viewing angle control liquid crystal panel 2 of the present embodiment, and FIG. 16 (b) is a conventional switch of homogeneous alignment. It is a schematic diagram of the liquid crystal layer of a liquid crystal display. FIG. 17 (a) shows the liquid crystal molecules M to M that sequentially transmit light along the optical path when light passes through the liquid crystal layer shown in FIG. 16 (a) parallel to the xz plane and at an elevation angle Θ. When viewed from the optical path direction

1 5

FIG. FIG. 17 (b) shows a liquid crystal layer shown in FIG. Liquid crystal molecules that sequentially transmit light along the optical path when light is transmitted at an elevation angle Θ m

1

It is a projection figure at the time of looking at ~ m from the optical path direction.

Five

[0053] By comparing Fig. 17 (a) and Fig. 17 (b), the following can be understood. That is, in the case of the homogeneous alignment shown in FIG. 17 (b), the light transmitted through the liquid crystal layer is affected by the birefringence of the liquid crystal molecules, but the major axis direction of the liquid crystal molecules m to m is almost constant. So LCD

1 5

Little affected by the optical rotation of the molecule. In the case of homogeneous alignment, the degree of influence of birefringence varies depending on the elevation angle Θ (that is, the apparent retardation value of the liquid crystal layer varies). On the other hand, in the case of the hybrid alignment shown in FIG. 17 (a), the light transmitted through the liquid crystal layer 24 is twisted by the liquid crystal molecules M to M together with the birefringence of the liquid crystal molecules.

1 5

Due to the nematic alignment, it is affected by the optical rotation due to the rotation of the liquid crystal molecules in the long axis direction. Therefore, in the homogeneous orientation, when the narrow viewing angle mode is selected, there is an optimum value of the elevation angle θ for shielding the transmitted light, and when the elevation angle is made larger than that angle, leakage light is generated. On the other hand, in the no-branch alignment, the light shielding state can be maintained even when the elevation angle is large due to the effect of optical rotation.

In the present embodiment, as illustrated in FIG. 2, the force exemplifying a configuration in which the polarization transmission axes of the polarizing plates 25 and 26 and the rubbing directions of the alignment films 23a and 23b are substantially orthogonal to each other. In the S and viewing angle control liquid crystal panel 2, the polarization transmission axes of the polarizing plates 25 and 26 and the rubbing direction of the alignment films 23a and 23b may be substantially parallel. However, the configuration in which the polarization transmission axes of the polarizing plates 25 and 26 and the rubbing directions of the alignment films 23a and 23b are substantially orthogonal is preferable in terms of improving the direction force S and the light shielding level.

[0055] [Second Embodiment]

A display device according to a second embodiment of the present invention will be described below with reference to the drawings. Note that components similar to those described in the first embodiment are denoted by the same reference numerals as in the first embodiment, and description thereof is omitted. FIG. 18 is a schematic cross-sectional view showing a schematic configuration of the display device 200 which is particularly useful for the second embodiment. As shown in FIG. 18, the display device 200 that has the power of the second embodiment includes a negative C plate 31 between a polarizing plate 25 and a light-transmitting substrate 21 a of the liquid crystal cell 20. In the present embodiment, the polarization transmission axis is parallel to the rubbing direction for the alignment films 23a and 23b of the liquid crystal cell 20. Polarizers 25 and 26 are arranged. However, as in the first embodiment, the light shielding level is good even if the polarizing plates 25 and 26 are arranged so that the polarization transmission axis is orthogonal to the rubbing direction with respect to the alignment film 23a 23b of the liquid crystal cell 20. In terms of improvement.

Further, in the display device 200 of the present embodiment, the drive circuit 27 switches and applies two-level voltages of Vb and Va to the liquid crystal layer 24. Vb is a voltage of about 5.0V to about 10.0V, and Va is a voltage of about 1.0V 4.0V. When the voltage Vb is applied, the liquid crystal molecules in the liquid crystal layer 24 are in a state substantially equal to the home-mouth-pick orientation as shown in FIG. 19 (a). That is, by applying a relatively high voltage Vb, the action of the electric field is more dominant than the action of the anchoring force received from the alignment film with respect to the movement of the liquid crystal molecules. The major axis is aligned so that it is almost completely parallel to the substrate normal.

[0057] The negative C plate is a retardation film in which the relationship of Nx = Ny> Nz is established when the refractive index in the plane direction is Nx, Ny and the refractive index in the thickness direction is Nz. When the phase difference of the liquid crystal layer 24 in the home-to-mouth pick orientation as shown in Fig. 19 (a) is R (positive value) and the phase difference of the negative C plate 31 is R (negative value), these positions are The condition of the following (Equation 1) where the phase difference is

C

It is preferable to satisfy.

[0058] R + R = 0 (Formula 1)

c c

However, the absolute value of the phase difference R of the negative C plate 31 is slightly smaller than the R value if there is a small pretilt angle on the horizontal alignment film 23b side even when the voltage Vb is applied.

A high value is preferable. For example, when the retardation of the liquid crystal layer 24 of the liquid crystal cell 20 is about 1500 nm, it is preferable to use a film having a retardation of about 1300 nm as the negative C plate 31. Here, FIG. 20 shows a range of preferable values of the retardation R of the negative C plate 31 with respect to the value of the retardation R of the liquid crystal layer 24 of the liquid crystal cell 20 C C

The In FIG. 20, the preferred range is a range in which the visibility is good in all directions in the wide viewing angle mode. The optimum range is a range in which better visibility can be obtained in the wide range of viewing angle mode than in the case where the negative C plate 31 is not used. FIG. 21 (a) is a chart showing the transmittance when the voltage Vb is applied to the liquid crystal layer 24 in the viewing angle control liquid crystal panel 2 in a state where the negative C plate 31 is laminated. FIG. 21 (b) is a chart showing the transmittance when the voltage Va is applied to the liquid crystal layer 24. As shown in FIG. 21 (a), when the voltage Vb is applied to the liquid crystal layer 24 by the drive circuit 27, compared to the wide viewing angle mode of the first embodiment (FIG. 4 (a)), It can be seen that the range that appears bright is expanding. In addition, as shown in FIG. 21 (b), when the voltage Va is applied to the liquid crystal layer 24 by the drive circuit 27, the display device 100 is in the narrow viewing angle mode when the voltage Va is applied to the first embodiment ( It can be seen that a narrow viewing angle equivalent to that in Fig. 4 (b)) is obtained.

[0060] In addition, when the display device 100 of the first embodiment is observed from a viewing angle with a large elevation angle in the wide viewing angle mode, the display device 100 may be slightly colored. On the other hand, in the display device 200 of the present embodiment, such coloring was not seen. Further, in the display device 200 of the present embodiment, as in the display device 100 of the first embodiment, when the narrow viewing angle mode is set, the pounding in the range where the elevation angle is large can be suppressed more than in the past. It was.

[0061] As described above, the display device 200 of the present embodiment includes the negative C plate 31 between the liquid crystal cell 20 and the polarizing plate 25, thereby preventing coloring in the wide viewing angle mode and sandwiching it. While maintaining the viewing angle in the viewing angle mode in a narrow range, it is possible to further widen the viewing angle in the wide viewing angle mode. As shown in Fig. 19 (a), an effective phase difference occurs when a positive nematic liquid crystal with IJ aligned with the major surface of the substrate is almost perpendicular to the substrate surface (homeotope pick orientation) is seen from an angle. This causes a narrowing of the viewing angle. The negative C-plate 31 can cancel the phase difference and improve the viewing angle.

FIG. 18 shows a configuration in which a negative C plate 31 is arranged between the liquid crystal cell 20 and the polarizing plates 25 and 26 and outside the light-transmitting substrate 21a on the vertical alignment film 23a side. . However, a configuration in which the negative C plate 31 is disposed outside the translucent substrate 21b on the side of the horizontal alignment film 23b (that is, between the translucent substrate 21b and the polarizing plate 26) is also acceptable. However, as shown in FIG. 18, the configuration in which the negative C plate is arranged on the vertical alignment film 23a side has a higher viewing angle improvement effect. Force to place negative C plate near the vertical alignment film 23a Can the phase difference be canceled without being affected by other optical compensation (for example, by the horizontal alignment part)? That's it. Further, a negative C plate may be arranged between both the translucent substrate 21a and the polarizing plate 25 and between the translucent substrate 21b and the polarizing plate 26. In this case, the total force of the phase difference of the two negative C plates should be equal to the phase difference of one negative C plate in the configuration shown in FIG.

[0063] Although the embodiments of the present invention have been described above, the above embodiments are not intended to limit the present invention, and various modifications can be made within the scope of the invention.

For example, FIGS. 1 and 18 exemplify a configuration in which the viewing angle control liquid crystal panel 2 is arranged closer to the viewer than the display element (display liquid crystal panel 1). However, as a modification of FIG. 1 and FIG. 18, the same effect can be obtained even if the viewing angle control liquid crystal panel 2 is arranged between the display element (display liquid crystal panel 1) and the backlight 3. .

[0065] In the first and second embodiments, the configuration in which the viewing angle control liquid crystal panel 2 has two polarizing plates is exemplified. However, the display element is different from the first and second embodiments. In the case of the liquid crystal panel, the polarizing plate (not shown) provided in the display liquid crystal panel 1 can be shared as the polarizing plate of the viewing angle control liquid crystal panel 2.

[0066] In the first and second embodiments, an example in which a transmissive liquid crystal panel is provided as a display element has been described. However, the display element applicable to the display device of the present invention is not limited to this. For example, a reflective or transflective liquid crystal display panel can be used as the display element. In addition to liquid crystal display panels, for example, CRT (Cathode Ray Tube), plasma display, organic EL (Electronic Luminescence) element, inorganic EL element, LED (Light Emitting Diode) display, vacuum fluorescent display (Vacuum Fluorescent Display), Field emission device. A self-luminous display device such as a ray (Field Emission Display) or a surface-electric emission on-emitter display can also be used. For example, when a self-luminous display device such as an EL element is used as the display element, no light is required. In addition, the display element may be disposed on the viewer side with respect to the viewing angle control liquid crystal panel 2, or the viewing angle control liquid crystal panel 2 may be disposed on the viewer side with respect to the display element.

[0067] In any of the above embodiments, when the display state is a narrow viewing angle, a message, an image, an icon, or the like for informing the user of the fact is displayed on the screen of the display device. You may make it do. [0068] In any of the above embodiments, the driving circuit 27 of the viewing angle control liquid crystal panel 2 operates in accordance with the content of the image displayed on the display element, and the narrow viewing angle and the wide viewing angle are set. Even if you switch automatically, it is good. For example, when used to view web pages on the Internet, refer to the flag associated with each page according to the content of the web page, and it is preferable that the content is not seen by others. The drive circuit 27 may be controlled to automatically switch to the corner display state. Further, for example, when the browser is activated in the encryption mode, the display state may be switched to a narrow viewing angle.

[0069] In addition, when the display device is a part of the data input device or operates in association with the data input device, the input data type or the data type to be input is confidential. It can also be adjusted to switch the display state to a narrow viewing angle, for example. For example, when the user inputs some personal identification number, the drive circuit 27 may be controlled to automatically switch to the narrow viewing angle.

[0070] It should be noted that the viewing angle control liquid crystal panel may be formed as a module or a cover that can be removed from the display device, even if the deviation of the above-described embodiment is not sufficient. When such a removable module is attached to the display device, it can be electrically connected to the display device to obtain appropriate power and control signals.

[0071] In any of the above-described embodiments, an optical sensor (ambient sensor) that measures the ambient light of the display device is further provided, and when the measured value of the optical sensor falls below a predetermined threshold value, It is also preferable to set the display state to a narrow viewing angle.

It should be noted that the display device and the viewing angle control element that are useful in the present invention have a wide variety of uses. For example, it can be applied to displays such as notebook personal computers, personal digital assistants (PDAs), portable game consoles, or mobile phones, ATMs (automatic cashiers, machines), and public places. It is applied to the display of various devices such as information terminals, ticket vending machines, and in-vehicle displays.

[0073] Although the viewing angle control element according to the present invention may be implemented in a state of being incorporated in a display device, the viewing angle control element can be manufactured and distributed as a component of the display device. There is also sex. Industrial applicability

INDUSTRIAL APPLICABILITY The present invention can be industrially used as a display adaptable to various usage environments and applications by switching between a wide viewing angle and a narrow viewing angle, and a viewing angle control element used therefor.

Claims

The scope of the claims

[1] a display element driven according to an image to be displayed;

A display device including a viewing angle control element that is disposed on at least one of a back surface and a front surface of the display element and controls a viewing angle of the display element;

The viewing angle control element is:

A pair of translucent substrates, a vertical alignment film and a horizontal alignment film provided on each of the translucent substrates, and a hybrid alignment liquid crystal layer sandwiched between the vertical alignment film and the horizontal alignment film A liquid crystal cell;

A drive circuit for applying a voltage to the liquid crystal layer,

In the display device, the liquid crystal cell is disposed between two polarizing plates whose polarization transmission axes are disposed substantially in parallel.

By changing the alignment state of the liquid crystal molecules in the liquid crystal layer of the viewing angle control element by applying a voltage from the driving circuit, the display state is changed to a first state that provides a first viewing angle range, and a first state. A display device that is switchable between a second state that provides a second viewing angle range that is within the viewing angle range and is narrower than the first viewing angle range.

[2] When the driving circuit does not apply a voltage to the liquid crystal layer of the viewing angle control element, the first state is established, and when the driving circuit applies a predetermined voltage to the liquid crystal layer of the viewing angle control element, The display device according to claim 1, wherein the display device is in the second state.

[3] The display device according to [1], wherein a negative C plate is provided at least at one position between the liquid crystal cell and the two polarizing plates.

[4] The drive circuit applies a predetermined voltage V to the liquid crystal layer of the viewing angle control element.

2

The second state is established, and the driving circuit enters the first state by applying a predetermined voltage V higher than the predetermined voltage V to the liquid crystal layer of the viewing angle control element.

twenty one

Item 4. The display device according to Item 3.

[5] The predetermined voltage V is a liquid crystal molecule in the liquid crystal layer of the viewing angle control element.

1

5. The display device according to claim 4, which is a voltage value to be oriented.

[6] The display element is a display element that emits linearly polarized light,

One of the two polarizing plates is a polarizing plate provided in the display element. : The display apparatus according to any one of! To 5.

7. The display element is a transmissive liquid crystal display element, further comprising a backlight.

The display device according to one of?

8. The display device according to claim 7, wherein the viewing angle control element is arranged between the backlight and the transmissive liquid crystal display element.

[9] The viewing angle control element is disposed in front of the transmissive liquid crystal display element.

The display device according to 7.

[10] The display device according to any one of claims 6 to 6, wherein the display element is a reflective liquid crystal display element or a transflective liquid crystal display element.

[11] The display device according to any one of claims 1 to 5, wherein the display element is a self-luminous display element.

[12] The retardation of the liquid crystal layer of the viewing angle control element is in the range of 600 nm to 2500 nm,

The pretilt angle on the horizontal alignment film side is in the range of 1 ° to 20 °,

12. The display device according to claim 1, wherein a pretilt angle on the vertical alignment film side is in a range of 70 ° to 90 °.

[13] The retardation of the liquid crystal layer of the viewing angle control element is in the range of 600 nm to 2500 nm,

The pretilt angle on the horizontal alignment film side is in the range of 10 ° to 30 °;

12. The display device according to claim 1, wherein a pretilt angle on the vertical alignment film side is in a range of 75 ° to 90 °.

[14] The retardation of the liquid crystal layer of the viewing angle control element is in the range of 600 nm to 2500 nm,

The pretilt angle on the horizontal alignment film side is in the range of 20 ° to 40 °,

12. The display device according to claim 1, wherein a pretilt angle on the vertical alignment film side is in a range of 80 ° to 90 °.

[15] A viewing angle control element that is disposed on at least one of the back surface and the front surface of the display element that is driven in accordance with an image to be displayed and is used to control the viewing angle of the display element Because

A drive circuit for applying a voltage to the liquid crystal layer;

At least one polarizing plate,

The drive circuit changes the alignment state of the liquid crystal molecules in the liquid crystal layer, so that the light emission range is within the first viewing angle range and the first viewing angle range, which is different from the first viewing angle range. A viewing angle control element capable of switching between a narrower second viewing angle range.