HK1128774B - Liquid crystal display - Google Patents

Description

Liquid crystal display device having a plurality of pixel electrodes

Technical Field

The present invention relates to a liquid crystal display device including a viewing angle control panel that controls a viewing angle of a display panel.

Background

In general, a display device is required to have as wide a viewing angle as possible so that a clear image can be seen from any viewing angle. In particular, in liquid crystal display devices which have been widely spread recently, since liquid crystals themselves have viewing angle dependency, various techniques for widening the viewing angle have been developed.

However, depending on the usage environment, it may be appropriate that only the user himself or herself can view the display content at a narrow viewing angle. In particular, in a place such as a train or an airplane where many unspecified people may exist, a notebook Personal computer, a portable information terminal (PDA: Personal Data Assistant), a mobile phone, and other electronic devices are highly likely to be used. In such a use environment, it is not desirable to let others nearby view the display content from the viewpoint of keeping confidentiality, protecting privacy, and the like, and therefore it is desirable that the viewing angle of the display device is narrow. As described above, in recent years, there has been an increasing demand for switching the viewing angle of 1 display device between a wide viewing angle and a narrow viewing angle depending on the usage situation. This requirement is not limited to a liquid crystal display device, but is a common problem for any display device.

To meet such a demand, for example, patent document 1 proposes a technique in which a phase difference control device is provided in addition to a display device for displaying an image, and the viewing angle characteristic is changed by controlling a voltage applied to the phase difference control device. In patent document 1, chiral nematic liquid crystal, uniform liquid crystal, randomly aligned nematic liquid crystal, and the like are exemplified as liquid crystal modes used in a liquid crystal display device for phase difference control.

For example, patent documents 2 and 3 disclose a configuration in which a viewing angle control liquid crystal panel is provided above a display liquid crystal panel, the panels are sandwiched between two polarizing plates, and a voltage applied to the viewing angle control liquid crystal panel is adjusted to control a viewing angle. In patent document 2, the liquid crystal mode of the viewing angle control liquid crystal panel is a twisted nematic mode.

Patent document 1: japanese laid-open patent publication No. 11-174489 (published 7/2/1999)

Patent document 2: japanese laid-open patent publication No. 10-268251 (Japanese laid-open patent publication No. 10/9/1998)

Patent document 3: japanese laid-open patent publication No. 2005-309020 (published 2005-11-4-month)

Disclosure of Invention

However, although patent document 1 describes a case where switching between the wide viewing angle mode and the narrow viewing angle mode is possible by using the phase difference control liquid crystal display element, the effect thereof cannot be said to be sufficient. For example, as shown in fig. 20, patent document 1 shows a contrast ratio of 10: a contrast curve such as 1 surely reduces the contrast in the wide viewing angle direction in the narrow viewing angle mode. However, in such a change of degree, the display can still be sufficiently visually recognized by the adjacent person. The reason for this is because even if the contrast ratio is reduced to, for example, 2: 1, in general, the display can be sufficiently visually recognized.

The techniques of patent documents 2 and 3 also adjust the contrast by changing the voltage applied to the viewing angle control liquid crystal panel, thereby switching between a wide viewing angle and a narrow viewing angle. For example, in the wide view angle mode, the view angle distribution shown in fig. 21(a), (b), and (c) is obtained, whereas in the narrow view angle mode, the view angle distribution shown in fig. 22(a), (b), and (c) is formed.

That is, although the techniques of patent documents 1 to 3 also employ a method of switching between the wide view angle mode and the narrow view angle mode by reducing the contrast in the wide view angle direction, in this method, there is a problem that the shielding in the wide view angle direction, that is, the narrow view angle direction is not sufficient in the narrow view angle mode, and thus, others can see an image.

The present invention has been made in view of the above conventional problems, and an object thereof is to provide a liquid crystal display device capable of increasing the effect of a narrow viewing angle.

In order to solve the above problems, a liquid crystal display device according to the present invention includes a backlight, a display panel, and a viewing angle control panel that controls a viewing angle of the display panel, and a lens sheet is provided between the backlight and the display panel on a side closer to the backlight than the viewing angle control panel, or between the backlight and the viewing angle control panel on a side closer to the backlight than the display panel.

According to the above invention, the lens sheet is provided between the backlight and the display panel provided on the backlight side of the viewing angle control panel, or between the backlight and the viewing angle control panel provided on the backlight side of the display panel. Therefore, by condensing the light emitted from the backlight by the lens sheet, a narrow viewing angle can be achieved.

Therefore, a liquid crystal display device which can increase the effect of a narrow viewing angle can be provided.

In order to solve the above-described problems, a liquid crystal display device according to the present invention includes a backlight, a display panel, and a viewing angle control panel that controls a viewing angle of the display panel, and a lens sheet is provided between the backlight and the display panel on a side closer to the backlight than the viewing angle control panel, or between the backlight and the viewing angle control panel on a side closer to the backlight than the display panel.

In this way, by stacking a plurality of single layers, light emitted from the backlight can be condensed more narrowly than when the lens sheet is a single layer.

In the liquid crystal display device according to the present invention, the lens sheet may be composed of two lens sheets, i.e., a first lens sheet which is disposed on the backlight side and has a prism ridge pattern in a vertical stripe pattern with respect to the display panel, and a second lens sheet which is laminated on the first lens sheet and has a prism ridge pattern in a horizontal stripe pattern with respect to the display panel.

Thus, the light emitted from the backlight can be condensed so as to make a narrow viewing angle in the left-right direction by the first lens sheet having the prism ridge line pattern in the vertical stripe shape. Further, the second lens sheet having the prism ridge pattern in the horizontal stripe shape can condense light emitted from the backlight so as to realize a narrow viewing angle in the front-rear direction.

As a result, the use of two lens sheets, i.e., the first lens sheet and the second lens sheet, can efficiently realize a narrow viewing angle in the left-right and front-rear directions.

In the liquid crystal display device of the present invention, the display panel and the viewing angle control panel may include liquid crystal cells, respectively, and at least 1 polarizing plate which is not subjected to diffusion processing may be provided between the liquid crystal cell of the display panel and the liquid crystal cell of the viewing angle control panel.

Thus, at least 1 polarizing plate which is not subjected to diffusion treatment exists between the liquid crystal cell of the display panel and the liquid crystal cell of the viewing angle control panel, and therefore the effect of narrow viewing angle is not hindered. That is, for example, if a polarizing plate subjected to diffusion treatment is present between the liquid crystal cell of the display panel and the liquid crystal cell of the viewing angle control panel, the effect of narrowing the viewing angle is hindered.

In the liquid crystal display device according to the present invention, it is preferable that the viewing angle control panel includes a liquid crystal cell having a liquid crystal layer in which liquid crystal molecules are aligned vertically between a pair of translucent substrates, and a drive circuit for applying a voltage to the liquid crystal layer, the liquid crystal cell is disposed between two polarizing plates disposed to face each other so that polarization transmission axes are substantially orthogonal to each other, and the drive circuit switches a display state between a first viewing angle range and a second viewing angle range which is within the first viewing angle range and narrower than the first viewing angle range by changing an arrangement state of the liquid crystal molecules in the liquid crystal layer of the liquid crystal cell.

According to the above invention, two polarizing plates having polarization transmission axes substantially orthogonal to each other are arranged so as to sandwich the liquid crystal cell of the viewing angle control panel. The viewing angle control panel and the two polarizing plates do not necessarily need to be adjacent to each other, and any structural element may be interposed therebetween.

In the above configuration, if a predetermined voltage is applied to the liquid crystal layer to change the alignment state of the liquid crystal molecules and the birefringence of the liquid crystal is used to change the polarization state of the light emitted from the liquid crystal cell of the viewing angle control panel, the polarizing plate disposed on the observer side of the viewing angle control panel functions as a light detector, and the light emitted from the viewing angle control panel to the observer side can be transmitted or blocked according to the viewing angle. That is, the display state may be switched to any one of a wide viewing angle providing a first viewing angle range and a narrow viewing angle providing a second viewing angle range that is within the first viewing angle range and narrower than the first viewing angle range. Furthermore, "wide viewing angle" and "narrow viewing angle" do not mean a specific absolute angular range, but rather a relatively wide viewing angle and a relatively narrow viewing angle.

In the above configuration, by using the liquid crystal cell in which the liquid crystal molecules are vertically aligned, a narrow viewing angle state in which display can be visually recognized only at a limited viewing angle can be realized. Thus, as in the conventional viewing angle control technique, the viewing angle can be controlled by switching between transmission and shielding of light without lowering the display contrast on the wide viewing angle side. As a result, a liquid crystal display device can be provided which can increase the narrow viewing angle effect when switching to the narrow viewing angle mode.

In order to solve the above-described problems, a liquid crystal display device according to the present invention includes a backlight, a display panel, and a viewing angle control panel that controls a viewing angle of the display panel, and a lens sheet is provided between the backlight and the display panel on a side closer to the backlight than the viewing angle control panel, or between the backlight and the viewing angle control panel on a side closer to the backlight than the display panel.

According to the present invention, a liquid crystal display device includes a backlight, a display panel, and a viewing angle control panel for controlling a viewing angle of the display panel.

However, in the present invention, since the display panel and the viewing angle control panel each include a liquid crystal cell, and at least 1 polarizing plate without diffusion processing is provided between the liquid crystal cell of the display panel and the liquid crystal cell of the viewing angle control panel, it is possible to provide a liquid crystal display device capable of increasing the effect of a narrow viewing angle by using only this configuration without providing a lens sheet.

Still other objects, features and advantages of the present invention will become more fully apparent from the ensuing description. Further, the advantages of the present invention will become apparent from the following description with reference to the accompanying drawings.

Drawings

Fig. 1 is a diagram showing an embodiment of a liquid crystal display device according to the present invention, and is a cross-sectional diagram showing a configuration of a liquid crystal display device including a viewing angle control panel.

Fig. 2 is a view showing a modification of the liquid crystal display device, and is a sectional view showing a configuration of a liquid crystal display device in which a viewing angle control panel is provided above a display liquid crystal panel.

Fig. 3(a) is a perspective view showing an arrangement state of liquid crystal molecules in the narrow viewing angle mode of the viewing angle control panel, and (b) is a perspective view showing an arrangement state of liquid crystal molecules in the wide viewing angle mode of the viewing angle control panel.

Fig. 4 is a schematic view showing definition of the viewing angle of the laminated body of the viewing angle control panel and the second polarizing plate arranged in the same direction as fig. 3(a) and (b).

Fig. 5(a), (b), and (c) are views showing the positional relationship between the liquid crystal molecules and the transmission axis of the polarizing plate according to the viewing angle.

Fig. 6 is a view showing a luminance distribution in the narrow viewing angle mode of the liquid crystal display device.

Fig. 7 is a diagram showing a luminance distribution in the wide viewing angle mode of the liquid crystal display device.

Fig. 8 is a schematic view showing a configuration of a viewing angle control panel in which a retardation film is provided between a light-transmissive substrate and a polarizing plate in the liquid crystal display device.

Fig. 9(a) is a cross-sectional view showing a configuration of a liquid crystal display device in which two lens sheets, i.e., a first lens sheet and a second lens sheet, are provided as lens sheets.

Fig. 9(b) is an exploded perspective view showing a stacked state of the first lens sheet and the second lens sheet.

Fig. 10(a) is a diagram showing a luminance distribution of a general liquid crystal display device when there is no lens sheet, (b) is a diagram showing a luminance distribution of a general liquid crystal display device when there is a first lens sheet, (c) is a diagram showing a luminance distribution of a general liquid crystal display device when there is a second lens sheet, and (d) is a diagram showing a luminance distribution of a general liquid crystal display device when the first lens sheet and the second lens sheet are laminated.

Fig. 11(a) is a graph showing the luminance-polar angle characteristics in the horizontal direction in fig. 10(a) to (d), and (b) is a graph showing the luminance-polar angle characteristics in the vertical direction in fig. 10(a) to (d).

Fig. 12 is a diagram showing a luminance distribution in a narrow viewing angle mode in a liquid crystal display device in which a first lens sheet and a second lens sheet are stacked.

Fig. 13 is a view showing another embodiment of the liquid crystal display device of the present invention, and is a cross-sectional view showing a liquid crystal display device in which a polarizing plate between a viewing angle control panel and a display liquid crystal panel is used as a clean polarizing plate and a lens sheet is provided.

Fig. 14 is a view showing a modification of the liquid crystal display device, and is a cross-sectional view showing a liquid crystal display device in which the two lens sheets are the first lens sheet and the second lens sheet in the liquid crystal display device shown in fig. 13.

Fig. 15(a) is a graph showing a luminance distribution in the wide viewing angle mode in the liquid crystal display device shown in fig. 14, (b) is a graph showing luminance-polar angle characteristics in the horizontal direction in (a), and (c) is a graph showing luminance-polar angle characteristics in the vertical direction in (a).

Fig. 16(a) is a graph showing the luminance distribution in the narrow viewing angle mode in the liquid crystal display device shown in fig. 14, (b) is a graph showing the luminance-polar angle characteristic in the horizontal direction in (a), and (c) is a graph showing the luminance-polar angle characteristic in the vertical direction in (a).

Fig. 17 is a view showing another embodiment of the liquid crystal display device according to the present invention, and is a cross-sectional view showing a liquid crystal display device in which a polarizing plate between a viewing angle control panel and a display liquid crystal panel is used as a clean polarizing plate and a lens sheet is not provided.

Fig. 18(a) is a graph showing a luminance distribution in the wide viewing angle mode in the liquid crystal display device shown in fig. 17, (b) is a graph showing luminance-polar angle characteristics in the horizontal direction in (a), and (c) is a graph showing luminance-polar angle characteristics in the vertical direction in (a).

Fig. 19(a) is a graph showing the luminance distribution in the narrow viewing angle mode in the liquid crystal display device shown in fig. 17, (b) is a graph showing the luminance-polar angle characteristic in the horizontal direction in (a), and (c) is a graph showing the luminance-polar angle characteristic in the vertical direction in (a).

Fig. 20 is a view showing a view angle distribution of a conventional liquid crystal display device including a view angle control panel.

Fig. 21(a) is a graph showing a luminance distribution in a wide viewing angle mode in another conventional liquid crystal display device including a viewing angle control panel, (b) is a graph showing luminance-polar angle characteristics in a horizontal direction in (a), and (c) is a graph showing luminance-polar angle characteristics in a vertical direction in (a).

Fig. 22(a) is a graph showing a luminance distribution in a narrow viewing angle mode in the above-described conventional liquid crystal display device including the viewing angle control panel, (b) is a graph showing luminance-polar angle characteristics in the horizontal direction in (a), and (c) is a graph showing luminance-polar angle characteristics in the vertical direction in (a).

Description of the symbols

1 LCD panel for display (display panel)

2 visual field angle control panel

3 backlight source

10 liquid crystal display device (display device)

10a liquid crystal display device (display device)

10b liquid crystal display device (display device)

11 liquid crystal cell

12 LCD panel upper polarizer (polarizer)

13 liquid crystal panel lower polarizing plate

21 liquid crystal cell

21a light-transmitting substrate

21b light-transmitting substrate

21c liquid crystal molecules

22 polarizing plate on control panel

23 control panel lower polarizer (polarizer)

50 liquid crystal display device (display device)

50a liquid crystal display device (display device)

60 liquid crystal display device (display device)

X₂₂Polarized light transmission axis

X₂₃Polarized light transmission axis

Detailed Description

[ embodiment 1]

An embodiment of the present invention will be described below with reference to fig. 1 to 12. For convenience of explanation, the drawings referred to below simply show only the main components necessary for explaining the present invention among the components of one embodiment of the present invention. Therefore, the liquid crystal display device of the present invention may include any components not shown in the drawings referred to in the present specification. Note that the dimensions of the components in the drawings do not faithfully represent the dimensions of actual structural components, the dimensional ratios of the components, and the like.

First, the structure of the liquid crystal display device 10 according to the present embodiment will be described with reference to fig. 1. Fig. 1 is a cross-sectional view showing a schematic configuration of the liquid crystal display device 10.

As shown in fig. 1, a liquid crystal display device 10 includes two panels, i.e., a display liquid crystal panel 1 as a display panel for displaying an image and a viewing angle control panel 2 provided on the display liquid crystal panel 1. The display liquid crystal panel 1 is of a transmissive type, and uses a backlight 3 as a light source. In the present embodiment, a lens sheet 41 and a diffusion sheet 42 are laminated between the backlight 3 and the liquid crystal panel 1 for display.

The display liquid crystal panel 1 includes a liquid crystal cell 11 in which liquid crystal is sandwiched between a pair of translucent substrates, and an upper liquid crystal panel polarizer 12 and a lower liquid crystal panel polarizer 13 provided on the front and rear sides of the liquid crystal cell 11. The liquid crystal panel upper polarizer 12 is formed of a plate having a surface subjected to diffusion treatment such as AG (Anti Glare) treatment. The AG processing means a flash (reflection) prevention processing. For example, as a method for preventing specular reflection on a glass surface or the like, a surface of the polarizing plate 12 on the liquid crystal panel is slightly roughened, or a rough surface film is applied. As a result, for example, writing of the background can be prevented.

The lower liquid crystal panel polarizing plate 13 is formed of a so-called clean polarizing plate which is not surface-treated.

The liquid crystal mode and the cell structure of the liquid crystal cell 11 of the liquid crystal panel 1 for display are arbitrary. The driving mode of the display liquid crystal panel 1 is also arbitrary. That is, as the display liquid crystal panel 1, any liquid crystal panel capable of displaying characters, images, or moving images can be used. Further, the display liquid crystal panel 1 may be a panel capable of color display or may be a panel dedicated to monochrome display. Therefore, in fig. 1, the detailed configuration of the display liquid crystal panel 1 is not shown, and the description thereof is omitted.

The backlight 3 includes a reflection sheet 31, a light guide plate 32, and a diffusion sheet 33 in this order from below. A light source, not shown, is provided on a side surface of the light guide plate 32. The backlight 3 has a general structure, and any known backlight can be used.

The viewing angle control panel 2 is provided above the display liquid crystal panel 1, for example, as shown in the figure. However, this is not necessarily the case, and for example, as shown in fig. 2, the viewing angle control panel 2 may be provided below the display liquid crystal panel 1 in the liquid crystal display device 10 a.

The liquid crystal display device 10 of the present embodiment can switch between two modes of display states, i.e., a wide viewing angle in a state where the viewing angle at which the image of the liquid crystal panel 1 can be visually recognized is wide and a narrow viewing angle in a state where the viewing angle at which the image of the liquid crystal panel 1 can be visually recognized is narrow, by operating the liquid crystal switch in the viewing angle control panel 2. The narrow viewing angle is particularly suitable for use in a case where an image of the display liquid crystal panel 1 cannot be seen by others, and the wide viewing angle is suitable for use in a case where a person or other persons simultaneously want to see an image of the display liquid crystal panel 1 in a normal use.

As shown in fig. 1, the viewing angle control panel 2 includes: a liquid crystal cell 21 in which a liquid crystal layer is sandwiched between a pair of light-transmitting substrates 21a and 21b described later; a control panel upper polarizing plate 22 provided on the display liquid crystal panel 1 side of the liquid crystal cell 21; and a control panel lower polarizing plate 23 provided on the display liquid crystal panel 1 side of the liquid crystal cell 21. The liquid crystal layer of the liquid crystal cell 21 is constituted of nematic liquid crystal which is vertically aligned (isotropically aligned).

The surface of the polarizing plate 22 on the control panel is subjected to diffusion treatment such as AG treatment. Further, the control panel lower polarizing plate 23 is constituted by a so-called clean polarizing plate which is not subjected to surface treatment. The control panel lower polarizing plate 23 is not necessarily required, and may be omitted. That is, since at least one polarizing plate is required between the viewing angle control panel 2 and the display liquid crystal panel 1, the liquid crystal panel lower polarizing plate 23 can share the liquid crystal panel upper polarizing plate 12 of the display liquid crystal panel 1.

Here, the detailed structure and operation of the viewing angle control panel 2 will be described with reference to fig. 3(a) and (b). Fig. 3(a) and (b) are schematic views mainly showing the structure of the viewing angle control panel 2, where (a) shows the arrangement state of liquid crystal molecules in the narrow viewing angle mode and (b) shows the arrangement state of liquid crystal molecules in the wide viewing angle mode.

As shown in fig. 3(a) and (b), the liquid crystal cell 21 of the viewing angle control panel 2 includes a pair of translucent substrates 21a and 21 b. On the surfaces of the light-transmissive substrates 21a and 21b, transparent electrodes (not shown) are formed of, for example, ITO (Indium Tin Oxide). The liquid crystal panel 1 for display has an electrode structure corresponding to a display unit because it is necessary to drive liquid crystal in a display unit such as a pixel unit or a segment unit. However, the viewing angle control panel 2 is not limited to the electrode structure. For example, in order to perform uniform switching over the entire display surface, a structure may be adopted in which uniform transparent electrodes are formed over the entire surfaces of the transparent substrates 21a and 21b, and any other electrode structure may be adopted.

An alignment film, not shown, for aligning the liquid crystal molecules 21c is formed on the upper layer of the transparent electrode. The alignment film is subjected to a rubbing treatment by a known method. In FIGS. 3(a) and (b), the polishing directions of the respective translucent substrates 21a and 21b are indicated by arrows Ra and Rb. As shown in fig. 3(a) and (b), the polishing direction Ra of the alignment film with respect to the transparent substrate 21a is parallel to and opposite to the polishing direction Rb of the alignment film with respect to the transparent substrate 21 b.

That is, the liquid crystal cell 21 of the viewing angle control panel 2 is a so-called parallel cell having a twist angle of 0 (no twist). In the present embodiment, the liquid crystal injected into the liquid crystal cell 21 is a negative nematic liquid crystal with negative dielectric anisotropy. Therefore, the liquid crystal molecules 21c of the liquid crystal cell 21 are aligned such that the long axes of the molecules are perpendicular to the substrate surfaces of the transparent substrates 21a and 21b when no voltage is applied. The retardation d · Δ n of the liquid crystal layer of the liquid crystal cell 21 is, for example, 200nm to 350 nm.

When a voltage is applied between the electrodes (not shown) provided on the respective light-transmissive substrates 21a and 21b, as shown in fig. 3(a), the liquid crystal molecules 21c gradually change their direction in accordance with the magnitude of the applied voltage in a plane parallel to the normal lines of the light-transmissive substrates 21a and 21b and parallel to the rubbing directions Ra and Rb of the alignment films on the light-transmissive substrate 21a from a state perpendicular to the substrate surface. When the applied voltage reaches a predetermined value, the liquid crystal molecules 21c are aligned with their long axes parallel to the substrate surfaces of the light-transmissive substrates 21a and 21b, as shown in fig. 3 (b). That is, FIG. 3(a) shows the voltage V applied_L(e.g., a voltage of about 2.5V to 3.5V), the long molecular axes of the liquid crystal molecules 21c are inclined with respect to the normal to the transparent substrates 21a and 21 b. FIG. 3(b) shows the voltage V applied_H(e.g., 5.A voltage of 0V or more), the long axes of the liquid crystal molecules 21c are substantially parallel to the substrate surfaces of the light-transmissive substrates 21a and 21 b.

As shown in fig. 3(a), in the viewing angle control panel 2, a control panel lower polarizing plate 23 and a control panel upper polarizing plate 22 are provided below the liquid crystal cell 21, and the respective polarizing transmission axes X of the polarizing transmission axes X₂₃And a polarized light transmission axis X₂₂Are arranged in a substantially orthogonal manner.

In addition, as long as the polarized light passes through the axis X₂₃And the transmission axis X of polarized light₂₂When the angle is in the range of 80 to 100 degrees, a sufficient effect of switching the viewing angle can be obtained. Polarized light transmission axis X of polarizing plate 22 on control panel₂₂The polishing direction R of the alignment film on the transparent substrate 21a is inclined at an angle of 40 ° to 50 ° (preferably 45 °).

Here, the principle of switching the viewing angle between the wide viewing angle and the narrow viewing angle using the viewing angle control panel 2 having the above-described configuration will be described with reference to fig. 4 and 5 in addition to fig. 3(a) and (b). That is, the viewing angle control panel 2 switches the viewing angle between a wide viewing angle and a narrow viewing angle by switching the voltage applied to the liquid crystal cell 21. In addition, in the following description, the azimuth angle θ and the polar angle Φ with reference to the center of the polarizing plate 22 on the control panel represent the viewing angle from a certain viewpoint with respect to the viewing angle control panel 2. Fig. 4 is a view showing the viewing angle from 3 viewpoints P1 to P3 with respect to the viewing angle control panel 2 arranged in the same direction as fig. 3(a) and (b).

As shown in fig. 4, the azimuth angle θ is the rotation angle of a line connecting a foot from a viewpoint to a perpendicular line downward from a plane including the surface of the polarizing plate 22 on the control panel and the center 22c of the polarizing plate 22 on the control panel. In the example of FIG. 4, when the viewpoint P is ordered₁Is 0 deg., and the azimuth angle theta increases in the clockwise direction when viewed from the upper side in the normal direction of the polarizing plate 22 on the control panel.

In the example of fig. 4, the viewpoint P₂Azimuth angle ofθ₂Is 90 DEG, viewpoint P₃Azimuth angle theta of₃Is 180 deg.. The polar angle Φ is an angle formed by a straight line connecting the center 22c of the polarizing plate 22 on the control panel and the viewpoint and the normal line of the polarizing plate 22 on the control panel.

Here, with reference to fig. 5(a) to (c), a description will be given of a display state observed from each of the viewing points P1 to P3 shown in fig. 4 when the long axis of the liquid crystal molecules 21c shown in fig. 3(a) is inclined at a slight angle with respect to the normal to the transparent substrates 21a and 21b by the voltage VL applied to the liquid crystal cell 21.

First, with respect to the viewpoint P from FIG. 4₁Angle of view (azimuth angle θ)₁0 °), as shown in fig. 5(a), the short axis side of the liquid crystal molecules 21c faces the viewing angle direction. Thereby, with respect to the view point P₁The angle of view (c) of (d) is a viewing angle at which linearly polarized light emitted from the backlight 3 and entering the liquid crystal cell 21 through the control panel lower polarizer 23 is shielded by the control panel upper polarizer 22 without receiving birefringence due to the liquid crystal molecules 21 c. Therefore, with respect to the view point P₁Angle of view (azimuth angle θ)₁0 °), black display. In addition, when the voltage V is applied to the liquid crystal cell 21_LWhen the angle is about 2.5V to 3.5V as described above, the azimuth angle θ is set as shown in FIG. 5₁0 degree and polar angle phi of 30 degrees to phi<Within the range of 90 degrees, a sufficient light-shielding effect for preventing others from peeping can be obtained. Further, in FIG. 6, L₁～L₈Is to represent a luminance of 50cd/m²、100cd/m²、150cd/m²、200cd/m²、250cd/m²、300cd/m²、350cd/m²And 400cd/m²The view angle distribution of (a). Fig. 6 is a luminance distribution diagram when the lens sheet 41 is not present, or the first lens sheet 41a and the second lens sheet 41b are present.

In addition, with respect to the viewpoint P from FIG. 4₂Angle of view (azimuth angle θ)₂90 °), as shown in fig. 5(b), the major molecular axis of the liquid crystal molecule 21c is polarized light transmission to the polarizing plate 22 on the control panelOver axis X₂₂And controlling each of the slightly inclined states of the panel lower polarizing plates 23.

Thereby, with respect to the view point P₂The linearly polarized light emitted from the backlight 3 and entering the liquid crystal cell 21 through the control panel lower polarizer 23 is shielded by the control panel upper polarizer 22, although a particularly slight birefringence is generated by the liquid crystal molecules 21 c. Therefore, even from the viewpoint P₂Angle of view (azimuth angle θ)₂90 °), also becomes a black display.

Furthermore, with the viewpoint P₂The relative position, i.e. the azimuth angle theta is 270 deg. also according to the angle from the viewpoint P₂The same principle as in the observation of (2) is used to display black. In addition, when the voltage V is applied to the liquid crystal cell 21_LAs described above, when the voltage is about 2.5V to about 3.5V, the polar angle Φ is about 30 ° ≦ Φ when the azimuth angle θ is 90 ° and the azimuth angle θ is 270 °, as shown in fig. 6<Within the range of 90 degrees, a sufficient light-shielding state for preventing others from peeping can be obtained.

In addition, with respect to the viewpoint P from FIG. 4₃Angle of view (azimuth angle θ)₃180 °), as shown in fig. 5(c), the major molecular axes of the liquid crystal molecules 21c are aligned with respect to the polarization transmission axis X of the polarizing plate 22 on each control panel₂₂And a polarized light transmission axis X of the polarizing plate 23 under the control panel₂₃The tilt is about 45 °, and the long axis side of the liquid crystal molecules 21c is opposed to the viewing angle direction. Thereby, with respect to the view point P₃The angle of view of (1) is such that the linearly polarized light emitted from the backlight 3 and entering the liquid crystal cell 21 through the control panel lower polarizer 23 is birefringent due to the liquid crystal molecules 21c and matches the polarization transmission axis X of the control panel upper polarizer 22₂₂The polarization direction is rotated in a uniform manner and transmitted through the polarizing plate 22 on the control panel. Therefore, with respect to the view point P₃The display can be made to have a good display angle. In addition, when the voltage V is applied_LWhen the angle is about 2.5V to 3.5V as described above, the azimuth angle θ is set as shown in FIG. 6₃180 degrees and a polar angle phi of between 0 degrees and phi<In the range of 90 deg. of the above-mentioned material,a good display can be obtained.

As described above, when the voltage V for tilting the long axis of the liquid crystal molecule 21c by a slight angle with respect to the substrate normal is applied to the liquid crystal cell 21 of the viewing angle control panel 2_LIn this case, good display can be obtained only in the viewing angle range around the azimuth angle θ of 180 °, and the polarized light in the liquid crystal cell 21 is blocked by the upper polarizer 22 of the control panel for the other azimuth angles, resulting in black display.

Therefore, the voltage V is applied to the liquid crystal cell 21 of the viewing angle control panel 2_LIn the wide viewing angle direction, the light emitted from the backlight 3 can be shielded. That is, the display image on the display liquid crystal panel 1 cannot be viewed from the wide viewing angle direction, and the liquid crystal display device 10 can be set to a narrow viewing angle.

On the other hand, as shown in fig. 3(b), a voltage V is applied to the liquid crystal cell 21 of the viewing angle control panel 2 so that the major molecular axis of the liquid crystal molecule 21c is inclined substantially parallel to the substrate_HEven with respect to the viewpoint P shown in FIG. 4₁～P₃In any of these viewing angles, as shown in fig. 7, the liquid crystal display device 10 can be made to have a wide viewing angle by generating sufficient birefringence so that good display can be obtained with respect to all azimuth angles θ. Further, in FIG. 7, L₁～L₈Is to indicate a luminance of 130cd/m²、240cd/m²、350cd/m²、460cd/m²、570cd/m²、680cd/m²、790cd/m²And 900cd/m²The equipotential lines of each view angle distribution. Fig. 7 is a distribution diagram of luminance when the lens sheet 41 is not present or when the first lens sheet 41a and the second lens sheet 41b are present.

In the liquid crystal display device 10 of the present embodiment, the voltage V is applied_HOr applying a voltage V_LThe voltage applied to the liquid crystal cell 21 of the viewing angle control panel 2 is switched in at least two stages, and the display state of the liquid crystal display device 10 can be switched between the wide viewing angle mode and the narrow viewing angle mode.

As shown in fig. 8, the viewing angle control panel 2 may be configured to further include a retardation film 4 between the polarizing plate 22 and the transparent substrate 21a of the liquid crystal cell 21 on the control panel. When passing through the applied voltage V_LWhen the liquid crystal cell 21 is subjected to a narrow viewing angle, when viewed from viewing angles other than the range of 180 ° in the azimuth angle θ shown in fig. 4 (for example, the range of 0 °, 90 ° and 270 °), the linearly polarized light emitted from the backlight 3 and transmitted through the polarizing plate 23 under the control panel is caused to have a refractive index (n) of the liquid crystal molecules 21c (i.e., the range of 0 °, 90 ° and 270 °)_e，n_o) Birefringence is generated in the liquid crystal layer of the liquid crystal cell 21 to become elliptically polarized light.

This generates a component that passes through the polarizing plate 22 on the control panel, which causes light leakage. The retardation film 4 is provided for optically compensating the elliptically polarized light. That is, a retardation film that generates elliptically polarized light in such a manner as to cancel the elliptically polarized light generated in the liquid crystal layer of the liquid crystal cell 21 when in the narrow viewing angle mode is used as the retardation film 4. Further, the 3-dimensional refractive index axis N of the retardation film 4_X·N_Y·N_ZAs defined in fig. 8. I.e. 3-dimensional refractive index axis N_XIs the polarized light transmission axis X of the polarized light plate 22 on the control panel₂₂Vertical component, 3-dimensional refractive index axis N_YIs the polarized light transmission axis X of the polarized light plate 22 on the control panel₂₂Parallel component, 3-dimensional refractive index axis N_ZIs a component parallel to the normal of the polarizing plate 22 on the control panel.

However, in the above configuration, the narrow viewing angle characteristic is insufficient in the narrow viewing angle mode of the viewing angle control panel 2.

Therefore, in the present embodiment, as shown in fig. 1, a lens sheet 41 is provided between the backlight 3 and the viewing angle control panel 2. Further, the lens sheet 41 narrows the light from the backlight 3, and the narrow viewing angle characteristic can be increased in the narrow viewing angle mode. The lens sheet 41 has, for example, a vertical stripe prism ridge pattern. Further, a diffusion sheet 42 is provided on the lens sheet 41.

The lens sheet 41 has a wider narrow viewing angle characteristic than a single layer. In the case of 2 layers, for example, as shown in fig. 9(a) and 9(b), two lens sheet structures are preferable, that is, a first lens sheet 41a which is provided on the backlight 3 side and has a vertical stripe-shaped prism ridge line pattern with respect to the display liquid crystal panel 1, and a second lens sheet 41b which is laminated on the first lens sheet 41a and has a horizontal stripe-shaped prism ridge line pattern with respect to the display liquid crystal panel 1.

The effect of improving the viewing angle characteristics of the liquid crystal display device 10b including the first lens sheet 41a and the second lens sheet 41b will be described with reference to fig. 10(a) to (d) and fig. 11(a) and (b). That is, fig. 10(a) is a diagram showing a luminance distribution of a general liquid crystal display device when the lens sheet 41 is not provided, fig. 10(b) is a diagram showing a luminance distribution of a general liquid crystal display device when only the first lens sheet 41a is provided, fig. 10(c) is a diagram showing a luminance distribution of a general liquid crystal display device when the second lens sheet 41b is provided, and fig. 10(d) is a diagram showing a luminance distribution of a general liquid crystal display device when the first lens sheet 41a and the second lens sheet 41b are laminated. Fig. 11(a) is a graph showing the luminance-polar angle characteristics in the horizontal direction in fig. 10(a) to (d), and fig. 11(b) is a graph showing the luminance-polar angle characteristics in the vertical direction in fig. 10(a) to (d).

As is clear from fig. 10(a) (b) and fig. 11(a) (b), when only the first lens sheet 41a having a vertical stripe prism ridge pattern with respect to the liquid crystal panel 1 is inserted, the polar angle in the horizontal direction becomes small. On the other hand, as is clear from fig. 10(a) (c) and fig. 11(a) (b), when only the second lens sheet 41b having a prism ridge pattern in a horizontal stripe pattern with respect to the liquid crystal panel 1 for display is inserted, the polar angle in the vertical direction becomes small. As is clear from fig. 10(a) and (d) and fig. 11(a) and (b), when both the first lens sheet 41a having a prism ridge line pattern in a vertical stripe pattern with respect to the display liquid crystal panel 1 and the second lens sheet 41b having a prism ridge line pattern in a horizontal stripe pattern with respect to the display liquid crystal panel 1 are inserted, the polar angles in both the horizontal direction and the vertical direction become smaller.

As a result, it is found that the narrow viewing angle characteristic is increased by inserting the lens sheet 41, and when the first lens sheet 41a and the second lens sheet 41b described above are laminated, the narrow viewing angle characteristic is further increased.

Actually, in the liquid crystal display device 10 of the present embodiment, the luminance distribution in the narrow viewing angle mode is obtained for the stacked first lens sheet 41a and second lens sheet 41b, and as a result, the luminance distribution shown in fig. 12 is obtained.

When the luminance distribution shown in fig. 12 is compared with fig. 6, it can be confirmed that the narrow viewing angle characteristic in the narrow viewing angle mode is increased.

In this way, the liquid crystal display device 10 of the present embodiment is provided with the lens sheet 41 or the first lens sheet 41a and the second lens sheet 41b between the backlight 3 and the display liquid crystal panel 1 or the viewing angle control panel 2. Therefore, the light emitted from the backlight 3 is condensed by the lens sheet 41 or the first and second lens sheets 41a and 41b, thereby achieving a narrow viewing angle. Therefore, the liquid crystal display devices 10 and 10a can be provided which can increase the effect of the narrow viewing angle.

In the liquid crystal display device 10b of the present embodiment, a plurality of lens sheets are preferably stacked. Thus, by stacking a plurality of single layers, light emitted from the backlight 3 can be condensed more narrowly than when the lens sheet is a single layer.

In the liquid crystal display device 10b of the present embodiment, the lens sheets are configured by two lens sheets, that is, a first lens sheet 41a which is provided on the backlight 3 side and has a prism ridge line pattern in a vertical stripe pattern with respect to the display liquid crystal panel 1, and a second lens sheet 41b which is laminated on the first lens sheet 41a and has a prism ridge line pattern in a horizontal stripe pattern with respect to the display liquid crystal panel 1. The vertical stripe shape with respect to the display liquid crystal panel 1 means that the display liquid crystal panel 1 is in the vertical direction with respect to the display liquid crystal panel 1 when the display liquid crystal panel 1 is viewed in the normal direction.

Thus, the light emitted from the backlight 3 can be condensed so as to make a narrow viewing angle in the left-right direction by the first lens sheet 41a having the prism ridge line pattern in the vertical stripe shape. Further, the second lens sheet 41b having the prism ridge pattern in the horizontal stripe shape can condense light emitted from the backlight 3 so as to realize a narrow viewing angle in the front-rear direction.

As a result, the narrow viewing angle can be efficiently achieved in the left-right and front-rear directions by using two lens sheets, i.e., the first lens sheet 41a and the second lens sheet 41 b. In addition, in the present embodiment, as shown in fig. 9(b), it is experimentally found that the first lens sheet 41a having a prism ridge line pattern in a vertical stripe pattern with respect to the display liquid crystal panel 1 is provided on the backlight 3 side, and the second lens sheet 41b having a prism ridge line pattern in a horizontal stripe pattern with respect to the display liquid crystal panel 1 is laminated thereon, which has a shielding effect as compared with the arrangement in which the vertical and horizontal directions are changed.

In the liquid crystal display device 10, 10a, 10b of the present embodiment, the viewing angle control panel 2 includes a liquid crystal cell 21 having a liquid crystal layer in which liquid crystal molecules 21c are aligned vertically between a pair of light-transmitting substrates 21a, 21b, and a drive circuit for applying a voltage to the liquid crystal layer, and the liquid crystal cell 21 is disposed on the transmission axis X of polarized light₂₂And a polarized light transmission axis X₂₃The driving circuit switches the display state between a first viewing angle range and a second viewing angle range within and narrower than the first viewing angle range by changing the arrangement state of liquid crystal molecules 21c in the liquid crystal layer of the liquid crystal cell 21 between two control panel upper polarizers 22 and two control panel lower polarizers 23 arranged to face each other in a substantially orthogonal manner.

Thus, the polarizing plate 22 on the control panel disposed on the observer side of the viewing angle control panel 2 functions as a light detector, and can transmit or block light emitted from the viewing angle control panel 2 to the observer side in accordance with the viewing angle.

As a result, it is possible to provide 10.10 a.10 b which can increase the narrow viewing angle effect when switching to the narrow viewing angle mode.

[ embodiment 2]

If other embodiments of the present invention are explained with reference to fig. 13 to 16, they are as follows. The configuration other than that described in this embodiment is the same as that of embodiment 1. For convenience of explanation, the same reference numerals are assigned to members having the same functions as those shown in the drawings of embodiment 1, and the explanation thereof will be omitted.

As shown in fig. 13, in the liquid crystal display device 50 of the present embodiment, as compared with the liquid crystal display device 10 of embodiment 1, the upper polarizing plate 12 of the liquid crystal panel of the display liquid crystal panel 1 and the lower polarizing plate 23 of the control panel of the viewing angle control panel 2 are not subjected to the diffusion process (shown as "upper polarizing plate (cleaning) 12" and "lower polarizing plate (cleaning) 23" in fig. 13). In addition, in the same manner as in fig. 13, the liquid crystal panel upper polarizing plate 12 is provided on the display liquid crystal panel 1, and the control panel lower polarizing plate 23 is provided on the viewing angle control panel 2, and neither of them is subjected to the diffusion process, but is not necessarily limited thereto. For example, a polarizing plate common to the liquid crystal cell 11 of the liquid crystal panel 1 for display and the liquid crystal cell 21 of the viewing angle control panel 2 may be provided, and the polarizing plate may not be subjected to diffusion treatment.

In the same drawing, the viewing angle control panel 2 is provided above the display liquid crystal panel 1, but the present invention is not necessarily limited to this. That is, the order of stacking the display liquid crystal panel 1 and the viewing angle control panel 2 may be changed, and the display liquid crystal panel 1 may be provided above the viewing angle control panel 2.

That is, in the liquid crystal display device 50 of the present embodiment, the control panel lower polarizing plate 23 of the viewing angle control panel 2 is a non-diffusion-processed polarizing plate, and the liquid crystal panel upper polarizing plate 12 of the display liquid crystal panel 1 is also a non-diffusion-processed polarizing plate. Even in such a configuration, the narrow viewing angle effect can be increased.

In addition, as shown in fig. 14, the lens sheet 41 may be a liquid crystal display device 50a in which a first lens sheet 41a and a second lens sheet 41b are laminated in the liquid crystal display device 50.

The performance of the liquid crystal display device 50a will be described with reference to fig. 15(a), (b), and (c) and fig. 16(a), (b), and (c). Here, fig. 15(a) is a graph showing the luminance distribution of the liquid crystal display device 50a in the wide viewing angle mode, fig. 15(b) is a graph showing the luminance-polar angle characteristic in the horizontal direction in fig. 15(a), and fig. 15(c) is a graph showing the luminance-polar angle characteristic in the vertical direction in fig. 15 (a). Fig. 16(a) is a graph showing the luminance distribution in the liquid crystal display device 50a in the narrow viewing angle mode, fig. 16(b) is a graph showing the luminance-polar angle characteristic in the horizontal direction in fig. 16(a), and fig. 16(c) is a graph showing the luminance-polar angle characteristic in the vertical direction in fig. 16 (a).

As is clear from fig. 16(a), (b), and (c), the viewing angle is narrower than the luminance distribution in the narrow viewing angle mode shown in fig. 12 of embodiment 1. It is also understood that the narrow viewing angle increasing effect is to make the viewing angle narrower than the luminance distribution in the wide viewing angle mode shown in fig. 7 of embodiment 1 and the luminance distribution in the wide viewing angle mode shown in fig. 15(a) of the present embodiment.

In this way, in the liquid crystal display devices 50 and 50a of the present embodiment, the control panel lower polarizer 23 and the liquid crystal panel upper polarizer 12 which are not subjected to diffusion processing are provided between the liquid crystal cell 11 of the display liquid crystal panel 1 and the liquid crystal cell 21 of the viewing angle control panel 2. That is, the control panel lower polarizer 23 and the liquid crystal panel upper polarizer 12 are both constituted by polarizers that are not subjected to diffusion treatment.

Thus, the control panel lower polarizer 23 and the liquid crystal panel upper polarizer 12 which are not subjected to diffusion processing are present between the liquid crystal cell 11 of the display liquid crystal panel 1 and the liquid crystal cell 21 of the viewing angle control panel 2, and therefore the effect of narrow viewing angle is not hindered. That is, for example, when the polarizing plate 12 on the liquid crystal panel is subjected to diffusion treatment, the effect of narrowing the viewing angle is hindered.

[ embodiment 3]

If still other embodiments of the present invention are explained with reference to fig. 17 to 19, they are as follows. The configuration other than that described in this embodiment is the same as that of embodiment 1. For convenience of explanation, the same reference numerals are assigned to members having the same functions as those shown in the drawings of embodiment 1, and the explanation thereof will be omitted.

In the liquid crystal display device 50 and the liquid crystal display device 50a according to embodiment 2 described above, in a configuration including the lens sheet 41 or the first lens sheet 41a and the second lens sheet 41b, a polarizing plate that is not subjected to diffusion processing is provided between the display liquid crystal panel 1 and the viewing angle control panel 2.

However, even if the lens sheet 41 or the first and second lens sheets 41a and 41b are not provided, the configuration in which the polarizing plate that is not subjected to the diffusion process is provided between the liquid crystal cell 11 of the liquid crystal panel 1 for display and the liquid crystal cell 21 of the viewing angle control panel 2 has an effect of increasing the narrow viewing angle.

That is, in the liquid crystal display device 60 of the present embodiment, as shown in fig. 17, the display liquid crystal panel 1 is provided on the backlight 3, the viewing angle control panel 2 is further provided on the display liquid crystal panel 1, and the lens sheet 41, the first lens sheet 41a, and the second lens sheet 41b are not present.

In the same drawing, the viewing angle control panel 2 is provided above the display liquid crystal panel 1, but the present invention is not necessarily limited to this. That is, the display liquid crystal panel 1 may be provided above the viewing angle control panel 2 by changing the lamination order of the display liquid crystal panel 1 and the viewing angle control panel 2.

The performance of the liquid crystal display device 60 will be described with reference to fig. 18(a), (b), and (c) and fig. 19(a), (b), and (c). Here, fig. 18(a) is a graph showing the luminance distribution of the liquid crystal display device 60 in the wide viewing angle mode, fig. 18(b) is a graph showing the luminance-polar angle characteristic in the horizontal direction in fig. 18(a), and fig. 18(c) is a graph showing the luminance-polar angle characteristic in the vertical direction in fig. 18 (a). Fig. 19(a) is a graph showing the luminance distribution of the liquid crystal display device 60 in the narrow viewing angle mode, fig. 19(b) is a graph showing the luminance-polar angle characteristic in the horizontal direction in fig. 19(a), and fig. 19(c) is a graph showing the luminance-polar angle characteristic in the vertical direction in fig. 19 (a).

As is clear from fig. 19(a), (b), and (c), the viewing angle is narrower than the luminance distribution in the narrow viewing angle mode shown in fig. 6 of embodiment 1. It is also understood that the effect of increasing the narrow viewing angle is to make the viewing angle narrower than the luminance distribution in the wide viewing angle mode shown in fig. 7 and the luminance distribution in the wide viewing angle mode shown in fig. 18(a) of embodiment 1.

As described above, in the liquid crystal display device 60 of the present embodiment, the lens sheet 41 or the first and second lens sheets 41a and 41b are not provided.

However, in the present embodiment, since the control panel upper polarizing plate 12 and the control panel lower polarizing plate 23 which are not subjected to diffusion processing are provided between the liquid crystal cell 11 of the display liquid crystal panel 1 and the liquid crystal cell 21 of the viewing angle control panel 2, the liquid crystal display device 60 which can increase the effect of a narrow viewing angle can be provided even with this configuration.

In addition, according to embodiments 1 to 3, the display liquid crystal panel 1 may be any one of a transmissive liquid crystal display panel, a reflective liquid crystal display panel, and a transflective liquid crystal display panel.

Industrial applicability

The present invention is applicable to a liquid crystal display device including a backlight, a display panel, and a viewing angle control panel for controlling a viewing angle of the display panel. The liquid crystal display device can be applied to, for example, any of a transmission type liquid crystal display device, a reflection type liquid crystal display device, and a transflective type liquid crystal display device.

Claims (7)

1. A liquid crystal display device comprising a backlight, a display panel, and a viewing angle control panel for controlling a viewing angle of the display panel, characterized in that:

providing a lens sheet disposed between the backlight and the display panel on the side closer to the backlight than the viewing angle control panel, or between the backlight and the viewing angle control panel on the side closer to the backlight than the display panel,

the viewing angle control panel includes a liquid crystal cell having a liquid crystal layer in which liquid crystal molecules are vertically aligned between a pair of light-transmitting substrates, and a drive circuit for applying a voltage to the liquid crystal layer,

the liquid crystal cell is arranged between two polarizing plates arranged so that polarizing transmission axes are substantially orthogonal to each other,

the driving circuit switches a long molecular axis of liquid crystal molecules of a liquid crystal layer of the liquid crystal cell between an alignment state parallel to a substrate surface of the transparent substrate and an alignment state inclined with respect to a normal line of the transparent substrate, and controls transmission by the polarizing plate, thereby switching a display state between a first viewing angle range and a second viewing angle range within and narrower than the first viewing angle range.

2. A liquid crystal display device comprising a backlight, a display panel, and a viewing angle control panel for controlling a viewing angle of the display panel, characterized in that:

a plurality of lens sheets stacked between the backlight and the display panel on the side closer to the backlight than the viewing angle control panel, or between the backlight and the viewing angle control panel on the side closer to the backlight than the display panel,

the viewing angle control panel includes a liquid crystal cell having a liquid crystal layer in which liquid crystal molecules are vertically aligned between a pair of light-transmitting substrates, and a drive circuit for applying a voltage to the liquid crystal layer,

the liquid crystal cell is arranged between two polarizing plates arranged so that polarizing transmission axes are substantially orthogonal to each other,

the driving circuit switches a long molecular axis of liquid crystal molecules of a liquid crystal layer of the liquid crystal cell between an alignment state parallel to a substrate surface of the transparent substrate and an alignment state inclined with respect to a normal line of the transparent substrate, and controls transmission by the polarizing plate, thereby switching a display state between a first viewing angle range and a second viewing angle range within and narrower than the first viewing angle range.

3. The liquid crystal display device according to claim 2, wherein:

the lens sheet is a first lens sheet which is arranged on the backlight side and has a vertical stripe-shaped prism ridge line pattern relative to the display panel; and a second lens sheet laminated on the first lens sheet and having a prism ridge pattern in a horizontal stripe shape with respect to the display panel.

4. The liquid crystal display device according to claim 1, wherein:

the display panel and the viewing angle control panel respectively comprise liquid crystal units, and at least 1 polarizing plate which is not subjected to diffusion treatment is arranged between the liquid crystal unit of the display panel and the liquid crystal unit of the viewing angle control panel.

5. The liquid crystal display device according to claim 2, wherein:

the display panel and the viewing angle control panel respectively comprise liquid crystal units, and at least 1 polarizing plate which is not subjected to diffusion treatment is arranged between the liquid crystal unit of the display panel and the liquid crystal unit of the viewing angle control panel.

6. The liquid crystal display device according to claim 3, wherein:

the display panel and the viewing angle control panel respectively comprise liquid crystal units, and at least 1 polarizing plate which is not subjected to diffusion treatment is arranged between the liquid crystal unit of the display panel and the liquid crystal unit of the viewing angle control panel.

7. A liquid crystal display device comprising a backlight, a display panel, and a viewing angle control panel for controlling a viewing angle of the display panel, characterized in that:

the display panel and the viewing angle control panel respectively comprise liquid crystal cells, and at least 1 polarizing plate without diffusion treatment is arranged between the liquid crystal cell of the display panel and the liquid crystal cell of the viewing angle control panel,

the viewing angle control panel includes a liquid crystal cell having a liquid crystal layer in which liquid crystal molecules are vertically aligned between a pair of light-transmitting substrates, and a drive circuit for applying a voltage to the liquid crystal layer,

the liquid crystal cell is arranged between two polarizing plates arranged so that polarizing transmission axes are substantially orthogonal to each other,

the driving circuit switches a long molecular axis of liquid crystal molecules of a liquid crystal layer of the liquid crystal cell between an alignment state parallel to a substrate surface of the transparent substrate and an alignment state inclined with respect to a normal line of the transparent substrate, and controls transmission by the polarizing plate, thereby switching a display state between a first viewing angle range and a second viewing angle range within and narrower than the first viewing angle range.