Image display device

Abstract

Provided are a liquid crystal panel capable of controlling the viewing angle while suppressing the thickness, and a video display device provided with the liquid crystal panel. This image display device is provided with: a liquid crystal panel provided with a first transparent substrate, a first electrode, a liquid crystal layer, a second electrode, an interlayer insulating film, a third electrode, and a second transparent substrate in this order; the liquid crystal layer has an overlapping region that overlaps the second electrode and a non-overlapping region that does not overlap the second electrode, so that the liquid crystal layer has a transparent region that has a highly transmissive state and a switching region that switches between the highly transmissive state and the low transmissive state. The liquid crystal layer is sandwiched between a pair of polarizing plates.

Description

Technical Field

[0001] The following disclosure relates to an image display device. Background Art

[0002] Image display devices having display panels such as liquid crystal panels have become widely used in various devices such as televisions, mobile phones, and PC monitors. In such image display devices, in recent years, research has been conducted on improving viewing angle characteristics so that the same image can be observed whether it is observed from a narrow viewing angle range or a wide viewing angle range. On the other hand, from the perspective of maintaining privacy, research has been conducted on display methods in which an image can be observed from a narrow viewing angle range but it is difficult to observe the image from a wide viewing angle range. Thus, a display device is required that can switch between a public mode (also called a wide viewing angle mode) in which the same image can be observed from a narrow viewing angle range or a wide viewing angle range, and a privacy mode (also called a narrow viewing angle mode) in which an image can be observed from a narrow viewing angle range but it is difficult to observe the image from a wide viewing angle range.

[0003] Regarding the technology of switching viewing angle modes, for example, Patent Document 1 discloses an optical element having a first region including a light-transmitting material between a pair of transparent substrates, and a second region disposed between the first region and including a liquid crystal material that is selectively switched between a light-transmitting state and a scattering or absorbing state. In addition, Patent Document 2 discloses a viewing angle control element, wherein the first region having a certain transmittance and a second region that can switch between a certain transmittance and a certain transmittance smaller than the transmittance are provided for each pixel.

[0004] Patent document 3 discloses a method of generating a longitudinal electric field by further providing an electrode on the other opposing substrate in a liquid crystal display device having an FFS structure in which a transverse electric field is generated between a pair of electrodes provided on one substrate of a pair of substrates. Patent document 4 discloses a method of making the third electrode not overlap with at least a portion of an optical opening provided in a picture element after further providing a third electrode on the color filter substrate in a liquid crystal panel having an FFS type electrode structure in which a first electrode and a second electrode are stacked on a first substrate via an insulating layer, a liquid crystal layer, and a color filter substrate.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Publication No. 2007-206373

[0008] Patent Document 2: Japanese Patent Application Publication No. 2005-221756

[0009] Patent Document 3: Japanese Patent Application Publication No. 2007-178907

[0010] Patent Document 4: Japanese Patent Application Publication No. 2021-67852 Summary of the invention

[0011] Problem that the invention aims to solve

[0012] Fig.13A 1 is a schematic cross-sectional view illustrating a wide viewing angle mode of an image display device 1R of a comparative embodiment. Fig. 13B 1 is a schematic cross-sectional view illustrating a narrow viewing angle mode of an image display device 1R of a comparative embodiment. Fig.13A and Fig. 13B The image display device 1R shown includes, in order from the observation side to the back side: a display panel 10 ; a liquid crystal panel 20R including polymer dispersed liquid crystal (PDLC); a louver layer 30R; and a backlight 40 .

[0013] The display panel 10 includes, in order from the observation surface side to the back surface side, a CF substrate 110 including a color filter (CF: Color Filter) layer and a TFT substrate 120 including a thin film transistor (TFT: Thin Film Transistor).

[0014] The liquid crystal panel 20R includes a pair of electrodes 230 and a liquid crystal layer 240R including PDLC sandwiched between a pair of transparent substrates 210 and 220. The PDLC has a structure in which a liquid crystal component is dispersed in a polymer network. Fig.13A and Fig. 13B As shown, the liquid crystal panel 20R can switch between the transmission state and the scattering state by using the refractive index difference between the liquid crystal component and the polymer network caused by the change in the orientation state of the liquid crystal component by applying a voltage to the liquid crystal layer 240R. When a PDLC of a type that scatters when no voltage is applied is used, the liquid crystal panel 20R becomes a scattering state when no voltage is applied, and becomes a transmission state when a voltage is applied.

[0015] The barrier layer 30R has a structure in which light shielding portions 31 mainly formed of a light absorbing material and transparent portions 32 mainly formed of a transparent resin are alternately arranged in parallel. The barrier layer 30R has a function of transmitting light 1LA in the front direction of the light from the backlight source 40 and shielding light 1LB in the oblique direction of the light from the backlight source 40. That is, the barrier layer 30R has a function of transmitting light at a low polar angle and shielding light at a high polar angle.

[0016] In the image display device 1R, in either the wide viewing angle mode or the narrow viewing angle mode, the oblique light 1LB from the backlight source 40 is blocked (interrupted) by the barrier layer 30R, and only the front light 1LA is transmitted through the barrier layer 30R (see FIG. Fig.13A and Fig. 13B ). When no voltage is applied, the light 1LA transmitted through the barrier layer 30R in the front direction is scattered (attenuated) in the liquid crystal panel 20R, so that the light is diffused and incident on the display panel 10 (see Fig.13A On the other hand, when a voltage is applied, the light 1LA in the front direction that passes through the barrier layer 30R is not scattered but passes through the liquid crystal panel 20R and enters the display panel 10 (see Fig. 13B ).

[0017] Thus, when no voltage is applied, the image display device 1R can transmit the light from the backlight source from the low polar angle side to the high polar angle side, thereby realizing a wide viewing angle mode. On the other hand, when a voltage is applied, the light from the backlight source is not transmitted on the high polar angle side, but is transmitted only on the low polar angle side, thereby realizing a narrow viewing angle mode. However, in order to switch between the wide viewing angle mode and the narrow viewing angle mode, the liquid crystal panel 20R and the barrier layer 30R are separately added to the display panel 10 as components, so there is a problem that the thickness becomes larger.

[0018] In the optical element described in Patent Document 1, the first region in the light-transmitting state and the second region selectively switched between the light-transmitting state and the scattering or absorption state are physically separated by using different materials. Such an optical element has various problems for practical use, such as difficulty in narrowing the viewing angle by conventional liquid crystal processes or complicated manufacturing processes.

[0019] For example, in Patent Document 1, it is recorded that UV photosensitive resin is preferably used as the translucent material forming the first region. When UV photosensitive resin is used, the thickness of the resin layer becomes thicker. In this regard, in Patent Document 1, as a diagram example of a composite material forming the second region for obtaining a narrow viewing angle (60°), an example is recorded in which the height is set to 300 μm when the width is 10 to 30 μm and the pitch is 200 μm. The thickness of the translucent material forming the first region is equivalent to the height of the diagram example, but in order to achieve the height of 300 μm, it is difficult to cope with it through the usual liquid crystal process (generally the height is within 10 μm). Therefore, when UV photosensitive resin is used as the above-mentioned translucent material, it is difficult to narrow the viewing angle. As the above-mentioned translucent material, a polymer material containing liquid crystal molecules, more specifically a UV-curable composite material in which liquid crystal molecules are dispersed in an ultraviolet-curable polymer, is also exemplified. In this case, in order to make the first region a translucent state, a process of applying a voltage for UV curing as shown in FIG. 11 of Patent Document 1 is required. Therefore, the manufacturing process of the optical element becomes complicated.

[0020] In the viewing angle control element described in Patent Document 2, for example, the first region is composed of a columnar transmissive resin layer, and the second region is composed of a liquid crystal layer. In this case, a general photolithography method can be used to form a fine pattern of the columnar transmissive resin layer with good dimensional accuracy, so the viewing angle control element can be manufactured without changing the existing liquid crystal manufacturing process. Therefore, the viewing angle control element can prevent the image quality from being reduced due to the decrease in brightness of the image display element at a wide viewing angle while achieving both a wide viewing angle and a narrow viewing angle, and is therefore extremely useful in the field of display devices. However, there is still room for research to further simplify the manufacturing process and more easily achieve viewing angle control.

[0021] In the methods described in Patent Documents 3 and 4, in the display liquid crystal (panel) that displays the image, an attempt is made to control the viewing angle by having a substrate having an FFS structure and a relative electrode disposed on the opposite substrate side of the substrate. Among them, the method described in Patent Document 4 can be combined with a flexible viewing angle control (veil-view; anti-peeping) function, and can provide a display device that ensures privacy from the left and right and tilt directions of the liquid crystal panel while obtaining high transmittance and high contrast, so it is very useful. However, in these methods, there is still room for research in order to be able to control the viewing angle without being limited by the structure of the display liquid crystal (panel) that displays the image.

[0022] The present invention has been made in view of the above-mentioned current situation, and an object of the present invention is to provide a liquid crystal panel capable of controlling the viewing angle while suppressing the thickness, and an image display device including the liquid crystal panel.

[0023] Solutions for solving problems

[0024] (1) One embodiment of the present invention is an image display device, comprising a liquid crystal panel and a display panel for displaying an image, wherein the liquid crystal panel comprises a first transparent substrate, a first electrode, a liquid crystal layer, a second electrode, an interlayer insulating film, a third electrode and a second transparent substrate in order, the liquid crystal layer comprises an overlapping region overlapping with the second electrode and a non-overlapping region not overlapping with the second electrode, so that the liquid crystal layer has a transparent region and a switching region, the transparent region is a region having a high transmittance state, the switching region is a region that switches between a high transmittance state and a low transmittance state, and the liquid crystal layer is clamped by a pair of polarizing plates.

[0025] (2) In addition, one embodiment of the present invention is an image display device, in addition to the configuration of (1) above, capable of applying different voltages to the transparent region and the switching region.

[0026] (3) In addition, an embodiment of the present invention is an image display device, in addition to the structure of (1) or (2), the thickness of the non-overlapping area is less than 30 μm.

[0027] (4) In addition, a certain embodiment of the present invention is an image display device, in which, based on the structure of (1), (2) or (3), the second electrode is a transparent electrode or an electrode containing a light absorbing material.

[0028] (5) In addition, a certain embodiment of the present invention is an image display device that, in addition to the structure of (1), (2), (3) or (4), further includes a backlight.

[0029] (6) In addition, an embodiment of the present invention is an image display device, in addition to the structure of (5) above, wherein the backlight has a local dimming function.

[0030] (7) In addition, a certain embodiment of the present invention is an image display device, based on the structure of the above (1), the above (2), the above (3), the above (4), the above (5) or the above (6), the above display panel is a liquid crystal display panel or a self-luminous display panel.

[0031] Effects of the Invention

[0032] According to the present invention, it is possible to provide a liquid crystal panel capable of controlling the viewing angle while suppressing the thickness, and an image display device including the liquid crystal panel. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1This is a schematic cross-sectional view of the image display device according to Embodiment 1.

[0034] Figure 2A It is a schematic cross-sectional view illustrating the wide viewing angle mode of the image display device according to Embodiment 1.

[0035] Figure 2B It is a schematic cross-sectional view illustrating the narrow viewing angle mode of the image display device according to Embodiment 1.

[0036] Figure 3 1 is a conceptual diagram for explaining the thickness D of the non-overlapping region, the width W1 of the non-overlapping region, the width W2 of the overlapping region, and the viewing angle θ.

[0037] Figure 4 It is a schematic cross-sectional view of an image display device according to a modified example of the first embodiment.

[0038] Figure 5 It is a schematic plan view showing the arrangement of second electrodes in the liquid crystal panel included in the image display device according to Embodiment 1.

[0039] Figure 6 This is a schematic cross-sectional view of an image display device according to Embodiment 2.

[0040] Fig. 7A This is a schematic cross-sectional view of an image display device according to Embodiment 3.

[0041] Figure 7B It is a schematic cross-sectional view of an image display device according to a modified example of the third embodiment.

[0042] Fig. 8A It is a schematic cross-sectional view illustrating a wide viewing angle mode of an image display device according to a fourth embodiment.

[0043] Figure 8B It is a schematic cross-sectional view illustrating the narrow viewing angle mode of the image display device according to the fourth embodiment.

[0044] Fig.9A It is a schematic cross-sectional view illustrating a wide viewing angle mode of an image display device according to a fifth embodiment.

[0045] Fig. 9B It is a schematic cross-sectional view illustrating the narrow viewing angle mode of the image display device according to the fifth embodiment.

[0046] Fig.10 It is a schematic cross-sectional view of an image display device according to a seventh embodiment.

[0047] Fig.11A It is a schematic cross-sectional view for explaining the wide viewing angle mode in the image display device of Example 1.

[0048] Fig. 11BIt is a schematic cross-sectional view for explaining the narrow viewing angle mode in the image display device of Example 1.

[0049] Fig. 12A This is a waveform diagram of the voltage of each electrode when the image display device of Example 1 is in the wide viewing angle mode.

[0050] Fig. 12B This is a waveform diagram of the voltage of each electrode when the image display device of Example 1 is in the narrow viewing angle mode.

[0051] Fig.13A It is a cross-sectional schematic diagram illustrating a wide viewing angle mode of an image display device of a comparative form.

[0052] Fig. 13B It is a schematic cross-sectional view illustrating a comparative image display device in a narrow viewing angle mode.

[0053] Description of Reference Numerals

[0054] 1. 1R: Image display device

[0055] 1LA: Light from the front direction

[0056] 1LB: Light in an oblique direction

[0057] 10: Display Panel

[0058] 20, 20R: LCD panel

[0059] 30R: grille layer

[0060] 40: Backlight

[0061] 50: Polarizing plate

[0062] 110: Color filter (CF) substrate

[0063] 120: Thin Film Transistor (TFT) Substrate

[0064] 130: Liquid crystal layer

[0065] 150: Adhesive layer

[0066] 210: first transparent substrate

[0067] 220: Second transparent substrate

[0068] 230: Electrode

[0069] 231: First electrode

[0070] 232: Second electrode

[0071] 233: The third electrode

[0072] 240, 240R: Liquid crystal layer

[0073] 241: Overlapping area

[0074] 242: Non-overlapping area

[0075] 243: Switching area

[0076] 244: Transparent area

[0077] 250: Interlayer insulation film

[0078] 260, 261, 262: Power supply. DETAILED DESCRIPTION

[0079] (Definition of terms)

[0080] In this specification, the observation side refers to the side closer to the screen (display surface) of the image display device, and the rear side refers to the side farther from the screen (display surface) of the image display device.

[0081] The polar angle refers to an angle formed between a target direction (eg, a measurement direction) and a normal direction of a panel surface of a liquid crystal panel.

[0082] position It refers to the direction when the target direction is projected onto the screen of the liquid crystal panel, and is expressed by the angle (azimuth) formed with the reference direction.

[0083] Here, the reference position The horizontal right direction of the screen of the liquid crystal panel is set. The angle and azimuth are set to be positive angles counterclockwise from the reference azimuth and negative angles clockwise from the reference azimuth. Counterclockwise and clockwise both represent the rotation direction when the screen of the liquid crystal panel is viewed from the observation side (front). In addition, the angle represents the value measured in the state of looking down at the screen of the liquid crystal panel.

[0084] In the present specification, being parallel to each other means that the angle (absolute value) between the two is within the range of 0±3°, preferably within the range of 0±1°, more preferably within the range of 0±0.5°, and particularly preferably 0° (completely parallel).

[0085] The non-voltage-applied state refers to a state in which the voltage applied to the liquid crystal layer is less than the threshold voltage (including no voltage applied). The voltage-applied state refers to a state in which the voltage applied to the liquid crystal layer is greater than the threshold voltage. In this specification, the non-voltage-applied state is also referred to as the non-voltage-applied state, and the voltage-applied state is also referred to as the voltage-applied state.

[0086] The light transmittance is calculated by measuring the brightness of the LED backlight and the brightness after placing the sample on the LED backlight and normalizing it with the brightness of the LED backlight. The SR-UL1 spectroradiometer manufactured by Topcon was used for the measurement. The light reflectance was measured using the CM-2600d spectrophotometer manufactured by Konica Minolta (measurement wavelength range: 360nm to 740nm, integrating sphere method).

[0087] The present invention is not limited to the following embodiments, and the design can be modified appropriately within the scope of the present invention.

[0088] (Implementation Method 1)

[0089] Figure 1 It is a schematic cross-sectional view of the image display device involved in this embodiment. Figure 2A It is a schematic cross-sectional view illustrating a wide viewing angle mode of the image display device according to the present embodiment. Figure 2B It is a schematic cross-sectional view illustrating a narrow viewing angle mode of the image display device according to the present embodiment.

[0090] like Figure 1 , Figure 2A as well as Figure 2B As shown, the image display device 1 of this embodiment includes a liquid crystal panel 20 and a display panel 10 for displaying an image. Thus, an image display device that can suppress thickness and control viewing angle can be realized. The image display device 1 of this embodiment further includes a backlight source 40. In this embodiment, an image display device that can display an image on the display panel 10 using light from the backlight source 40 and can suppress thickness and control viewing angle can be realized.

[0091] <LCD Panel>

[0092] The liquid crystal panel 20 includes, in order, a first transparent substrate 210, a first electrode 231, a liquid crystal layer 240, a second electrode 232, and a second transparent substrate 220. Between the second electrode 232 and the second transparent substrate 220, an interlayer insulating film 250 and a third electrode 233 are provided in order from the second electrode 232 side. Since the liquid crystal panel 20 has a function of controlling a viewing angle, it can be called a "viewing angle control unit".

[0093] A pair of polarizing plates 50 are disposed on the back side and the viewing side of the liquid crystal panel 20. Thus, the liquid crystal layer 240 is sandwiched between the pair of polarizing plates 50 (i.e., a sandwiched structure). Figure 2A and Figure 2BIn the embodiment, polarizing plates 50 are respectively arranged on the back side and the viewing side of the liquid crystal panel 20, and the polarizing plate 50 arranged on the display panel 10 side can also be shared with the polarizing plate provided in the display panel 10 (see Figure 1 ).

[0094] The liquid crystal layer 240 includes an overlapping region 241 that overlaps with the second electrode 232, and a non-overlapping region 242 that does not overlap with the second electrode 232. In addition, the liquid crystal layer 240 is sandwiched by a pair of polarizing plates 50 as described above. According to such a configuration, the liquid crystal layer 240 has a transparent region 244 and a switching region 243, wherein the transparent region 244 is a region having a high transmittance state, and the switching region 243 is a region that switches between a high transmittance state and a low transmittance state. By designing the power supply, the overlapping region 241 can be set as the switching region 243 and the non-overlapping region 242 can be set as the transparent region 244, and the overlapping region 241 can also be set as the transparent region 244 and the non-overlapping region 242 can be set as the switching region 243. In this embodiment, since the switching region 243 is switched between the high transmission state and the low transmission state by applying or not applying the voltage between the first electrode 231 and the second electrode 232 (262), the overlapping region 241 becomes the switching region 243, and the non-overlapping region 242 becomes the transparent region 244 (see Figure 1 , Figure 2A as well as Figure 2B However, in reality, not only the overlapping region 241 becomes the switching region 243. Depending on the application of the electric field between the electrodes, the boundary portion of the overlapping region 241 and the non-overlapping region 242 sometimes becomes the switching region 243, and other portions sometimes also become the switching region 243.

[0095] The key point of the present invention is that the liquid crystal layer 240 sandwiched by a pair of polarizing plates 50 has an overlapping region 241 overlapping with the second electrode 232 and a non-overlapping region 242 not overlapping with the second electrode 232, so that the liquid crystal layer 240 has: a transparent region 244 having a high transmission state; and a switching region 243 switching between a high transmission state and a low transmission state. That is, the important feature of the present invention is that by applying or not applying a voltage to each electrode, a region showing a high transmission state and a region showing a low transmission state are formed in the liquid crystal layer 240, and the liquid crystal layer 240 itself can function as a louver that can be switched on / off. The adjustment of the high transmission state and the low transmission state is performed by changing or maintaining the orientation (i.e., retardation) of the liquid crystal molecules of the liquid crystal layer 240 controlled by the application of a voltage, thereby changing the polarization state of light transmitted through one of the pair of polarizing plates 50 sandwiching the liquid crystal layer 240. That is, when the orientation of the liquid crystal molecules is changed or maintained, the polarization state is set to be able to transmit through the other polarization plate of the pair of polarization plates 50 or to be able to block light. In this way, the high transmission state and the low transmission state are adjusted.

[0096] Therefore, there is no particular limitation on the positions of the transparent region 244 and the switching region 243, or which region corresponds to the transparent region 244 and the switching region 243. Figure 1 , Figure 2A as well as Figure 2B The described method can be appropriately controlled by, for example, the width or pitch of the second electrode 232 , the cell thickness (ie, the thickness D of the non-overlapping region 242 ), the voltage applied to each electrode, and the like.

[0097] In this embodiment, the second electrode 232 and the third electrode 233 are arranged with the interlayer insulating film 250 therebetween. In this case, the first electrode 231 functions as a common electrode, and the application or non-application of the voltage in the non-overlapping region 242 (transparent region 244) can be controlled by the first electrode 231 and the third electrode 233, and the application or non-application of the voltage in the overlapping region 241 (switching region 243) can be controlled by the first electrode 231 and the second electrode 232. Therefore, in this embodiment, different voltages can be applied to the transparent region 244 and the switching region 243, respectively. Such an electrode structure can cope with various driving methods in the field of image display devices, and is therefore very useful.

[0098] The transparent region 244 is a region that exhibits a high-transmittance state by applying a voltage between the first electrode 231 and the third electrode 233 (261). The high-transmittance state is a state of high transparency to light, specifically, a state having a transmittance T1 or T2.

[0099] On the other hand, the switching area 243 refers to an area that switches between a high-transmittance state and a low-transmittance state. That is, it is an area that switches between a state with high transparency to light and a state with lower transparency than this state. Specifically, the high-transmittance state refers to a state with a transmittance T1, and the low-transmittance state refers to a state with a transmittance T3. Among them, T1, T2, and T3 satisfy the relationship of "T1≥T2>T3". The liquid crystal layer 240 in the low-transmittance state is, for example, in the same state as the light-shielding glass.

[0100] In this embodiment, as described later, in the wide viewing angle mode (see Figure 2A ), the transparent area 244 and the switching area 243 have a certain transmittance (also called visible light transmittance or light transmittance) T1. On the other hand, in the narrow viewing angle mode (refer to Figure 2B ), the transparent area 244 has a transmittance T2, and the switching area 243 has a transmittance T3. Among them, T1, T2 and T3 satisfy the relationship of "T1≥T2>T3". The transmittance T1 can be 100%. T3 can be 0%.

[0101] like Figure 2A and Figure 2B As shown, light is incident on the liquid crystal panel 20 from the back side (specifically, the backlight source 40). In a state where a voltage is applied between the first electrode 231 and the second electrode 232 (262), and a voltage is applied between the first electrode 231 and the third electrode 233 (261) (voltage applied state), the overlapping area 241 and the non-overlapping area 242 are not distinguished but integrated, and the entire liquid crystal layer 240 becomes a high transmission state (transparent area) (refer to Figure 2A That is, the transparent area 244 and the switching area 243 are in a state of having a transmittance T1. In this case, both the front light and the oblique light of the light incident on the liquid crystal panel 20 from the backlight source 40 directly pass through the liquid crystal panel 20 (see Figure 2A As a result, light from the back side (specifically, the backlight source 40 ) can be transmitted without loss from the low polar angle side to the high polar angle side, thereby realizing a wide viewing angle mode with high brightness.

[0102] Here, in the comparative video display device 1R, in the wide viewing angle mode, the light 1LB in the oblique direction is blocked by the barrier layer 30R, although it is not necessary to block it (see FIG. 1B ). Fig.13A In addition, in order to diffuse the light narrowed by the barrier layer 30R, the PDLC layer 240R scatters (attenuates) the light (see Fig.13A(y) portion). Therefore, transmission loss occurs in both the barrier layer 30R and the PDLC layer 240R, and thus the brightness in the wide viewing angle mode is insufficient. In contrast, the liquid crystal panel 20 of the present embodiment can transmit the light from the backlight source 40 without loss as described above, and thus can realize the wide viewing angle mode with high brightness.

[0103] In addition, in the present embodiment, in a state where no voltage is applied between the first electrode 231 and the second electrode 232 (262) and a voltage is applied between the first electrode 231 and the third electrode 233 (261) (no voltage applied state), the liquid crystal layer 240 itself functions as a barrier. That is, the light 1LB in the oblique direction of the light incident on the liquid crystal layer 240 from the backlight source 40 is shielded in the overlapping area 241 (switching area 243). Therefore, the overlapping area 241 (switching area 243) is in a low transmittance state, while the non-overlapping area 242 (transparent area 244) maintains a high transmittance state. That is, it becomes a state where the transparent area 244 has a transmittance T2 and the switching area 243 has a transmittance T3 (where T1 ≥ T2 > T3). The light 1LA in the front direction of the light incident on the liquid crystal layer 240 from the backlight source 40 is transmitted through the liquid crystal panel 20 without attenuation (refer to Figure 2B As a result, on the high polar angle side, the light from the back side (specifically, the backlight source 40) is attenuated, and only on the low polar angle side can the light from the back side be transmitted with the original brightness, thereby achieving a narrow viewing angle mode.

[0104] Thus, the liquid crystal panel 20 has a function of controlling the viewing angle by applying or not applying a voltage, and in addition to this function, also has a barrier function. Therefore, compared with the image display device 1R (see FIG. 1 ) of the comparative embodiment having only the liquid crystal panel 20R and the barrier layer 30R, Fig. 12A and Fig. 12B ) compared to the conventional image display device, the image display device of this embodiment can also suppress thickness, weight and manufacturing cost.

[0105] The overlapping region 241 is a region in the liquid crystal layer 240 that overlaps with the second electrode 232. Overlapping with the second electrode 232 means directly or indirectly contacting with the second electrode 232. As a scheme of indirectly contacting with the second electrode 232, for example, a scheme in which the overlapping region 241 contacts with the second electrode 232 via an alignment film can be cited. The alignment film refers to a film having a function of controlling the alignment of liquid crystal molecules contained in the liquid crystal layer 240. On the other hand, the non-overlapping region 242 is a region in the liquid crystal layer 240 that does not overlap with the second electrode 232.

[0106] The thickness D of the non-overlapping region 242 is preferably, for example, less than 100 μm. It is more preferably less than 50 μm, further preferably less than 30 μm, particularly preferably less than 20 μm, and most preferably less than 10 μm. In this way, the liquid crystal panel 20 of the image display device 1 of this embodiment can cope with the usual liquid crystal process (generally the height is within 10 μm), and has excellent viewing angle performance. The lower limit of the thickness is not particularly limited, but for example, it is preferably greater than 1 μm.

[0107] The thickness of the non-overlapping region 242 is also referred to as the height of the non-overlapping region 242. The thickness of the non-overlapping region 242 is equivalent to Figure 3 The distance D between the first electrode 231 and the interlayer insulating film 250 is denoted as follows.

[0108] It is suitable that the pitch of the non-overlapping region 242 is smaller than the pixel pitch of the display panel 10. Thus, the generation of moire fringes can be sufficiently suppressed. Among them, it is suitable that the pixel pitch of the display panel 10 is an integer multiple of the pitch of the non-overlapping region 242. The pixel pitch is more preferably 1 to 50 times the pitch of the non-overlapping region, and further preferably 6 to 24 times.

[0109] The width W1 of the non-overlapping region 242 and the width W2 of the overlapping region 241 can be appropriately set according to a desired viewing angle. For example, their ratio (W1 / W2) may be 100 / 1 to 500, or 100 / 50 to 300.

[0110] The viewing angle θ of the liquid crystal panel 20 in the narrow viewing angle mode can be arbitrarily set by the thickness D and the width W1 of the non-overlapping region 242. Specifically, it can be set by the following formula (1):

[0111] θ=2tan -1 (W1 / D) (1).

[0112] As described above, the liquid crystal panel 20 can cope with the usual liquid crystal process (generally within a height of 10 μm), so the image display device of this embodiment can easily achieve a narrow viewing angle mode with excellent viewing angle performance. In addition, in this embodiment, the transparent area 244 and the switching area 243 are not physically distinguished by material, but are distinguished by the design of the power supply (such as the configuration of the electrodes, etc.). The transparent area 244 and the switching area 243 are formed of the same material. Therefore, in this embodiment, there is no need for a UV curing process for pre-fixing to a transmissive state (transparent area) during manufacturing, such as shown in FIG. 11 of patent document 1. Therefore, the image display device 1 of this embodiment is also advantageous in that it can simplify the manufacturing process.

[0113] Hereinafter, the liquid crystal panel 20 will be further described.

[0114] The first transparent substrate 210 and the second transparent substrate 220 may be any substrate as long as they are transparent to visible light, for example, a glass substrate, a plastic substrate, etc. may be mentioned.

[0115] The first electrode 231 is arranged in a planar shape on the entire surface of the first transparent substrate 210. That is, the first electrode 231 is an electrode that covers the entire surface of the first transparent substrate 210. As a result, it is possible to switch between a wide viewing angle mode and a narrow viewing angle mode in the entire liquid crystal panel. The first electrode 231 can be a transparent electrode. As a transparent electrode, for example, it can be formed using a transparent conductive material such as indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), tin oxide (SnO) or an alloy thereof.

[0116] The second electrode 232 is arranged at intervals in a manner that the liquid crystal layer 240 can be divided into an overlapping region 241 overlapping with the second electrode and a non-overlapping region 242 not overlapping with the second electrode. Figure 5 As shown, the second electrode 232 is arranged in a stripe shape (also called a slit shape) when viewed from above. By setting it as such a configuration, the viewing angle in the left and right directions of the screen can be controlled. In this embodiment, the second electrode 232 uses a transparent electrode. Examples of the transparent electrode are as described above.

[0117] In this embodiment, the third electrode 233 is disposed in a planar shape on the entire surface of the second transparent substrate 220. That is, the third electrode 233 is an entire surface electrode that covers the second transparent substrate 220. The third electrode 233 may be a transparent electrode. Examples of the transparent electrode are as described above.

[0118] The liquid crystal layer 240 is composed of a liquid crystal composition containing liquid crystal molecules. For example, the liquid crystal molecules (also referred to as liquid crystal components) are preferably nematic liquid crystal molecules. Alternatively, the following formula (L) may be used:

[0119] Δε=(dielectric constant of the liquid crystal component in the long axis direction)-(dielectric constant of the liquid crystal component in the short axis direction)(L)

[0120] The liquid crystal molecules having a positive dielectric anisotropy (Δε) defined by the formula (L) may also be liquid crystal molecules having a negative dielectric anisotropy (Δε). Liquid crystal molecules having positive dielectric anisotropy are oriented in a direction parallel to the direction of the electric field, and liquid crystal molecules having negative dielectric anisotropy are oriented in a direction perpendicular to the direction of the electric field. In addition, liquid crystal molecules having positive dielectric anisotropy are also called positive liquid crystals (or positive liquid crystal molecules), and liquid crystal molecules having negative dielectric anisotropy are also called negative liquid crystals (or negative liquid crystal molecules).

[0121] In this embodiment, the liquid crystal molecules are particularly preferably liquid crystal molecules having a negative value. In addition, liquid crystal molecules that perform homeotropic alignment in a state where no voltage is applied (no voltage applied state) are suitable. The direction of the long axis of the liquid crystal molecules in the no voltage applied state is also referred to as the direction of the initial alignment of the liquid crystal molecules.

[0122] As the interlayer insulating film 250, any one of an organic insulating film, an inorganic insulating film, or a laminate of an organic insulating film and an inorganic insulating film can be used. As the organic insulating film, for example, an organic film (relative dielectric constant ε = 2 to 5) such as acrylic resin, polyimide resin, novolac resin, or a laminate thereof can be used. The film thickness of the organic insulating film is not particularly limited, for example, it is greater than 2 μm and less than 4 μm. As the inorganic insulating film, for example, silicon nitride (SiNx), silicon oxide (SiO 2 ) or a laminated film thereof. The thickness of the inorganic insulating film is not particularly limited, and may be, for example, above, the following.

[0123] The thickness of the interlayer insulating film 250 is not less than 0.1 μm and not more than 4 μm, and more preferably not less than 0.15 μm and not more than 0.35 μm.

[0124] <Polarizing plate>

[0125] As described above, the liquid crystal layer 240 is sandwiched by a pair of polarizing plates 50. The polarizing plate 50 may be a circular polarizing plate or a linear polarizing plate. A linear polarizing plate is a polarizing plate that has the function of extracting polarized light (linear polarized light) that vibrates only in a specific direction from unpolarized light (natural light), partially polarized light, or polarized light, and is distinguished from a circular polarizing plate. Among them, a linear polarizing plate is preferred.

[0126] In addition, the polarizing plate 50 may be an absorption-type polarizing plate or a reflection-type polarizing plate. An absorption-type polarizing plate refers to a polarizing plate that has the function of absorbing light vibrating in a specific direction and transmitting polarized light (linear polarized light) vibrating in a direction perpendicular thereto. A reflection-type polarizing plate refers to a polarizing plate that has the function of reflecting light vibrating in a specific direction and transmitting polarized light (linear polarized light) vibrating in a direction perpendicular thereto. Among them, an absorption-type polarizing plate is preferred. In particular, it is suitable to use an absorption-type linear polarizing plate.

[0127] The pair of polarizing plates 50 sandwiching the liquid crystal layer 240 may be arranged in a crossed Nicol arrangement or a parallel Nicol arrangement, but the crossed Nicol arrangement is suitable.

[0128] <Display Panel>

[0129] The display panel 10 may be any display panel that has the function of displaying an image. As described above, in the image display device 1 of this embodiment, since the liquid crystal panel 20 has the function of controlling the viewing angle, the function of controlling the viewing angle may not be given to the display panel 10. Therefore, the structure and driving mode of the display panel 10 are not restricted, and the design freedom of the display panel 10 is improved.

[0130] The display panel 10 can turn on / off image display. In this embodiment, a case where the display panel 10 is a liquid crystal display panel is taken as an example for description.

[0131] like Figure 1 As shown, the display panel 10 has a polarizing plate 50, a CF substrate 110 having a color filter (CF) layer, a liquid crystal layer 130, a TFT substrate 120 having a thin film transistor (TFT), and a polarizing plate 50 in order from the observation side to the back side. An adhesive layer 150 is usually provided between the display panel 10 and the liquid crystal panel 20 for attaching them. In addition, as described above, the polarizing plate 50 on the liquid crystal panel 20 side of the pair of polarizing plates 50 provided in the display panel 10 can be replaced as needed as one of the polarizing plates 50 in the pair of polarizing plates 50 for clamping the liquid crystal layer 240 provided in the liquid crystal panel 20. That is, even if the display panel 10 and the liquid crystal panel 20 do not each have a pair of polarizing plates, a part of them can be shared. In the present embodiment, the display panel 10 functions as a liquid crystal display panel, and therefore the image display device of the present embodiment is a liquid crystal display device. In Figure 2A and Figure 2B (and the following Figures 8A to 12B ), the display panel 10 does not have a liquid crystal layer 130, but may also have Figure 1 Likewise, the display panel 10 has a liquid crystal layer 130 .

[0132] The TFT substrate 120 has an insulating substrate, and in the display area, a plurality of gate lines extending in parallel to each other and a plurality of source lines extending in parallel to each other in a direction intersecting the gate lines through an insulating film are provided on the insulating substrate. The plurality of gate lines and the plurality of source lines are formed in a lattice shape as a whole in a manner of dividing each pixel. A thin film transistor as a switching element is arranged at the intersection of each source line and each gate line.

[0133] The TFT substrate 120 has: a planar common electrode, which is arranged on the surface of the liquid crystal layer 130 side of the insulating substrate; an insulating film, which covers the common electrode; and a pixel electrode, which is arranged on the surface of the liquid crystal layer side of the insulating film and is provided with a slit. The pixel electrode is arranged in each area surrounded by two adjacent source lines and two adjacent gate lines, and the pixel electrode is electrically connected to the corresponding source line via the semiconductor layer possessed by the thin film transistor. That is, the display panel 10 of this embodiment is a liquid crystal display panel in FFS (Fringe Field Switching) mode. The configuration of the common electrode and the pixel electrode can also be interchangeable. In this case, on the planar pixel electrode formed in a manner occupying each pixel area, a common electrode provided with a slit is arranged through an insulating film.

[0134] In the present embodiment, a display panel 10 in a horizontal alignment mode in which pixel electrodes and common electrodes are arranged on one substrate is described, but the display mode of the display panel 10 is not limited thereto, and may also be a vertical alignment mode in which pixel electrodes are arranged on a TFT substrate 120 and a common electrode is arranged on a CF substrate 110. The horizontal alignment mode refers to a mode in which liquid crystal molecules are aligned in a substantially horizontal direction relative to the respective main surfaces of a pair of substrates when no voltage is applied to the liquid crystal layer. In addition to the above-mentioned FFS mode, for example, an IPS (In-Plane Switching) mode may also be cited. In addition, a vertical alignment mode refers to a mode in which liquid crystal molecules are aligned in a substantially vertical direction relative to the respective main surfaces of a pair of substrates when no voltage is applied to the liquid crystal layer. For example, a VA (Vertical Alignment) mode, a TN (Twisted Nematic) mode, and the like may be cited.

[0135] Alignment films having the function of controlling the orientation of liquid crystal molecules contained in the liquid crystal layer 130 are respectively arranged between the TFT substrate 120 and the liquid crystal layer 130, and between the CF substrate 110 and the liquid crystal layer 130. In a no-voltage state where no voltage is applied between the pixel electrode and the common electrode, the liquid crystal molecules contained in the liquid crystal layer 130 are oriented approximately horizontally relative to the respective main surfaces of a pair of substrates.

[0136] The display panel 10 also includes a source driver electrically connected to the source line, a gate driver electrically connected to the gate line, and a controller. The gate driver sequentially supplies scanning signals to the gate lines based on the control of the controller. The source driver supplies data signals to the source lines based on the control of the controller when the TFT is in a voltage-applied state through the scanning signal. The pixel electrodes are respectively set to potentials corresponding to the data signals supplied via the corresponding TFTs, and a fringe electric field is generated between the pixel electrodes and the common electrode, causing the liquid crystal molecules of the liquid crystal layer to rotate. In this way, the magnitude of the voltage applied between the pixel electrode and the common electrode is controlled to change the delay of the liquid crystal layer and control the transmission and non-transmission of light.

[0137] As the CF substrate 110, a CF substrate generally used in the field of liquid crystal display panels can be used, for example, a structure in which components such as a color filter and a black matrix (BM: Black Matrix) layer are arranged on the surface of a transparent substrate such as a glass substrate. More specifically, the CF substrate 110 has: a black matrix arranged in a grid pattern corresponding to gate lines and source lines; a plurality of color color filters, including a red layer, a green layer, and a blue layer arranged in a periodic manner between the grids of the black matrix; an outer coating layer, which is provided in a manner covering these black matrices and each color filter, and includes a transparent insulating resin; and a photo spacer, which is provided in a columnar shape on the outer coating layer.

[0138] A pair of polarizing plates 50 and an adhesive layer 150 (OCA, etc.) are not particularly limited, and polarizing plates and adhesive layers used in ordinary liquid crystal display devices can be used. For the liquid crystal layer 130, a liquid crystal layer commonly used in ordinary liquid crystal display devices can also be used, so the description is omitted.

[0139] <Backlight>

[0140] The backlight source 40 is not particularly limited as long as it is a backlight source that irradiates light to the liquid crystal panel 20. For example, the backlight source 40 may include a light source and a reflector. As the light source, a general backlight source such as a cold cathode fluorescent lamp (CCFL) or a light emitting diode (LED) may be used.

[0141] In addition, the backlight source 40 can be a direct-lit type or an edge-lit type. When the edge-lit type is taken as an example, the backlight source 40 can be cited as having a light source, a reflective sheet, and a light guide plate. The light source is arranged on the end face of the light guide plate, and the reflective sheet is arranged on the back of the light guide plate. The light guide plate can use a light guide plate commonly used in the field of image display devices. As the reflective sheet, for example, an aluminum plate, a white polyethylene terephthalate (PET) film, a reflective film (for example, an ESR (Enhanced Specular Reflector) film manufactured by 3M Company), etc. can be cited.

[0142] <Other>

[0143] The image display device 1 of this embodiment includes, in addition to the above-mentioned components, external circuits such as TCP (tape carrier package), PCB (printed wiring board), optical films such as viewing angle expansion film and brightness enhancement film, outer frame (frame), and other components. Depending on the different components, other components may be assembled. There is no particular limitation on components other than those already described, and components commonly used in the field of image display devices can be used, so the description is omitted.

[0144] (Variation of Implementation Example 1)

[0145] In the image display device 1 of the first embodiment, the display panel 10 is arranged on the viewing side of the liquid crystal panel 20, but the display panel 10 may be arranged on the back side of the liquid crystal panel 20. Figure 4 As shown, the image display device 1 may also be configured to include a liquid crystal panel 20 , a display panel 10 , and a backlight 40 in this order from the observation surface side to the rear surface side. Figure 4 It is a schematic cross-sectional view of the image display device of this example.

[0146] (Implementation Method 2)

[0147] In this embodiment, features unique to this embodiment are mainly described, and description of contents overlapping with those in Embodiment 1 is omitted. This embodiment is substantially the same as Embodiment 1 except that the position of the second electrode 232 in the liquid crystal panel 20 and the design of the power supply are different.

[0148] Figure 6 is a schematic cross-sectional view of the image display device 1 of this embodiment. Figure 6 As shown, the image display device 1 of this embodiment includes a liquid crystal panel 20 and a display panel 10 for displaying an image. The liquid crystal panel 20 includes a first transparent substrate 210, a first electrode 231, a liquid crystal layer 240, a second electrode 232, and a second transparent substrate 220 in order, and an interlayer insulating film 250 and a third electrode 233 are provided in order from the second electrode 232 side between the second electrode 232 and the second transparent substrate 220. A pair of polarizing plates 50 are arranged on the back side and the observation side of the liquid crystal panel 20, thereby forming a structure in which the liquid crystal layer 240 is sandwiched by the pair of polarizing plates 50 (i.e., a sandwiched structure).

[0149] Figure 6 (b) is the main difference from the liquid crystal panel 20 of Embodiment 1 (see also Figure 1In the above-mentioned Embodiment 1, it is designed that the switching region 243 is switched to the high transmission state (see Figure 2A ) and low transmittance state (refer to Figure 2B ). In contrast, in the present embodiment, the switching region 243 is designed to switch between the high transmission state and the low transmission state by applying or not applying the voltage between the first electrode 231 and the third electrode 233 (261). In this case, in the present embodiment, the overlapping region 241 becomes the transparent region 244, and the non-overlapping region 242 becomes the switching region 243 (refer to Figure 6 However, in reality, not only the non-overlapping region 242 becomes the switching region 243, but also the boundary between the overlapping region 241 and the non-overlapping region 242 sometimes becomes the switching region 243, and other parts sometimes become the switching region 243, depending on the application of the electric field between the electrodes. Therefore, as in the first embodiment, the transparent region 244 and the switching region 243 are not limited to Figure 6 The described method can be appropriately controlled by, for example, the width or pitch of the second electrode 232, the cell thickness (ie, the thickness D of the non-overlapping region 242), the voltage applied to each electrode, etc. The same can be said for the following other embodiments.

[0150] (Implementation 3)

[0151] In this embodiment, features unique to this embodiment are mainly described, and description of contents overlapping with those of Embodiment 1 is omitted. This embodiment is substantially the same as Embodiment 1 except that the arrangement shape of the third electrodes 233 in the liquid crystal panel 20 is different.

[0152] Fig. 7A is a schematic cross-sectional view showing an example of an image display device according to this embodiment. Fig. 7A As shown, the image display device 1 includes a liquid crystal panel 20 and a display panel 10 for displaying an image. The liquid crystal panel 20 includes a first transparent substrate 210, a first electrode 231, a liquid crystal layer 240, a second electrode 232, and a second transparent substrate 220 in order, and an interlayer insulating film 250 and a third electrode 233 are provided in order from the second electrode 232 side between the second electrode 232 and the second transparent substrate 220.

[0153] Fig. 7A (c) is the main difference from the liquid crystal panel 20 of Embodiment 1 (see also Figure 1) In the above-mentioned first embodiment, the third electrode 233 is arranged in a planar shape on the entire surface of the second transparent substrate 220. That is, the third electrode 233 is a so-called full-surface electrode. In contrast, in this embodiment, the third electrode 233 is formed by patterning.

[0154] (Variation of Implementation Example 3)

[0155] In the liquid crystal panel 20 of the third embodiment, the switching region 243 is designed to switch between the high transmission state and the low transmission state by applying or not applying the voltage between the first electrode 231 and the second electrode 232 (262) (see Fig. 7A ). It can also be designed as in the above-mentioned embodiment 2 to switch the switching area 243 between the high transmission state and the low transmission state by applying or not applying the voltage (261) between the first electrode 231 and the third electrode 233 (refer to Figure 7B In this example, the design is as follows (see Figure 7B ), so the overlapping region 241 becomes the transparent region 244, and the non-overlapping region 242 becomes the switching region 243. However, as described above, in reality, not only the non-overlapping region 242 becomes the switching region 243, but the boundary portion between the overlapping region 241 and the non-overlapping region 242 sometimes also becomes the switching region 243, and other portions sometimes also become the switching region 243, depending on the application of the electric field between the electrodes.

[0156] Figure 7B (d) is the main difference from the liquid crystal panel 20 of Embodiment 2 (see also Figure 6 In the above-mentioned Embodiment 2, similarly to the above-mentioned Embodiment 1, the third electrode 233 is arranged in a planar shape on the entire surface of the second transparent substrate 220. That is, the third electrode 233 is a so-called full-surface electrode. In contrast, in this embodiment, the third electrode 233 is formed by patterning.

[0157] (Implementation 4)

[0158] In this embodiment, features unique to this embodiment are mainly described, and description of contents overlapping with those in Embodiment 1 is omitted. This embodiment is substantially the same as Embodiment 1 except that an electrode including a light absorbing material is used as the second electrode 232 included in the liquid crystal panel 20 .

[0159] Fig. 8A It is a schematic cross-sectional view illustrating a wide viewing angle mode of the image display device 1 according to the present embodiment. Figure 8B 2 is a cross-sectional schematic diagram illustrating the narrow viewing angle mode of the image display device 1 of this embodiment. Fig. 8A and Figure 8BAs shown, the image display device 1 includes a liquid crystal panel 20 and a display panel 10 for displaying an image, and further includes a backlight 40 .

[0160] The liquid crystal panel 20 includes a first transparent substrate 210, a first electrode 231, a liquid crystal layer 240, a second electrode 232, and a second transparent substrate 220 in order, and an interlayer insulating film 250 and a third electrode 233 are provided in order from the second electrode 232 side between the second electrode 232 and the second transparent substrate 220. A pair of polarizing plates 50 are arranged on the back side and the observation side of the liquid crystal panel 20, thereby forming a structure in which the liquid crystal layer 240 is sandwiched by the pair of polarizing plates 50.

[0161] In this embodiment, an electrode containing a light absorbing material is used as the second electrode 232 provided in the liquid crystal panel 20. By using an electrode containing a light absorbing material, it is possible to reduce obliquely emitted light (that is, specifically, light that becomes an oblique direction and is emitted from the liquid crystal panel 20), and thus the narrow viewing angle performance is further improved. As the electrode containing a light absorbing material, for example, a light absorbing material electrode, a laminate of a light absorbing material layer and a transparent electrode, a laminate of a reflective material and a light absorbing material electrode, a laminate of a reflective material, a light absorbing material layer and a transparent electrode, etc. are preferred.

[0162] As the light absorbing material, the transparent electrode, and the reflective material constituting the electrode including the light absorbing material, those generally used in the field of electrodes may be used, respectively.

[0163] For example, as the light absorbing material, a metal black matrix (also referred to as a metal BM) including a metal, a resin black matrix (also referred to as a resin BM) including a resin material, etc. can be cited. As the metal BM, for example, a metal film including aluminum, molybdenum, chromium, titanium or an alloy thereof can be cited, which can be a single-layer film or a multi-layer film. As the resin BM, for example, a black resist can be cited, among which a black photosensitive resin is preferred. Specifically, for example, a black photosensitive acrylic resin can be cited. The transmittance of the light absorbing material is preferably, for example, greater than 0% and less than 1%.

[0164] Examples of the transparent electrode are as described above, and among them, ITO is preferred.

[0165] As the reflective material, for example, highly reflective metals such as silver, aluminum, aluminum oxide, talc, titanium, and an alloy of silver, palladium, and copper (APC) can be used. 2 O 3 Equal high refractive index layer and MgF 2The reflective material can be formed by, for example, forming a metal film by evaporation, sputtering, etc. and then patterning it. The light reflectivity of the reflective material is preferably 90% or more and 100% or less.

[0166] In this embodiment, the case where a light absorbing material electrode is used as the second electrode 232 is particularly described. As the light absorbing material electrode, a metal BM is preferred. The metal BM is usually formed as a metal film with a small pattern on a substrate. As the material of the metal film, for example, aluminum, molybdenum, chromium, titanium or their alloys can be cited. As the film forming method, generally, there are evaporation methods, sputtering methods, vacuum film forming methods, etc. The patterning of the metal film is performed, for example, in the following manner: after a photoresist is coated on the metal film and dried, ultraviolet rays are irradiated through a photomask, and the unexposed part is dissolved with a developer to form a resist pattern, and then the metal is etched or the resist is stripped.

[0167] In the narrow viewing angle mode (see Figure 2B ), the light directly incident from the backlight source 40 to the switching area 243 (low transmission state) (refer to Figure 2B (a)) is shielded in the switching area 243. In contrast, in the narrow viewing angle mode of the present embodiment (refer to Figure 8B ), the light directly incident from the backlight source 40 to the switching area 243 (low transmission state) (refer to Figure 8B (f)) is blocked by the light absorbing material electrode (second electrode 232), so it is possible to further reduce the light emitted from the liquid crystal panel 20. Therefore, in this embodiment, the narrow viewing angle performance is further improved compared with the above-mentioned embodiment 1.

[0168] In addition, since there is light that does not directly enter the switching area 243 from the backlight source 40 but passes through the transparent area 244 to enter the switching area 243 (that is, light that enters the switching area 243 from the backlight source 40 without passing through the light absorbing material electrode (the second electrode 232)), there is also a small amount of oblique output light in the narrow viewing angle mode of this embodiment.

[0169] (Variation of Implementation Example 4)

[0170] In the above-mentioned Embodiment 4, the case where the light absorbing material electrode among the electrodes containing the light absorbing material is used as the second electrode 232 provided in the liquid crystal panel 20 is described, but a laminate of a light absorbing material layer and a transparent electrode can also be used as the second electrode 232. In this case, as in the above-mentioned Embodiment 4, the narrow viewing angle performance is further improved compared with the above-mentioned Embodiment 1.

[0171] As the light absorbing material layer, resin BM is preferable. As the laminate of the light absorbing material layer and the transparent electrode, specifically, a laminate in which a transparent electrode (such as ITO) is laminated on resin BM can be mentioned.

[0172] (Implementation 5)

[0173] In this embodiment, features unique to this embodiment are mainly described, and description of contents overlapping with those in Embodiment 1 is omitted. This embodiment is substantially the same as Embodiment 1 except that an electrode including a light absorbing material is used as the second electrode 232 included in the liquid crystal panel 20 .

[0174] Fig.9A It is a schematic cross-sectional view illustrating a wide viewing angle mode of the image display device 1 according to the present embodiment. Fig. 9B 2 is a cross-sectional schematic diagram illustrating the narrow viewing angle mode of the image display device 1 of this embodiment. Fig.9A and Fig. 9B As shown, the image display device 1 includes a liquid crystal panel 20 and a display panel 10 for displaying an image, and further includes a backlight 40 .

[0175] The liquid crystal panel 20 includes a first transparent substrate 210, a first electrode 231, a liquid crystal layer 240, a second electrode 232, and a second transparent substrate 220 in order, and an interlayer insulating film 250 and a third electrode 233 are provided in order from the second electrode 232 side between the second electrode 232 and the second transparent substrate 220. A pair of polarizing plates 50 are arranged on the back side and the observation side of the liquid crystal panel 20, thereby forming a structure in which the liquid crystal layer 240 is sandwiched by the pair of polarizing plates 50.

[0176] In this embodiment, an electrode containing a light absorbing material is used as the second electrode 232 of the liquid crystal panel 20. By using an electrode containing a light absorbing material, it is possible to reduce obliquely emitted light, so that the narrow viewing angle performance is further improved. Among the electrodes containing light absorbing materials, in this embodiment, a case where a laminate of a reflective material and a light absorbing material electrode is used as the second electrode 232 is particularly described.

[0177] As a reflective material, silver (Ag) is preferred among the above-mentioned metals. As a light absorbing material electrode, metal BM is preferred as described above. Therefore, as a laminate of a reflective material and a light absorbing material electrode, a laminate in which metal BM is laminated on silver is suitable. In addition, when an electrode containing a reflective material is used as the second electrode 232, it is preferably configured in such a way that the reflective material is located on the backlight source 40 side. That is, when a laminate of a reflective material and a light absorbing material electrode is used, it is suitable to configure the laminate in such a way that the reflective material is located on the backlight source 40 side.

[0178] As in the above-mentioned Embodiment 4, in this embodiment, the narrow viewing angle performance is further improved compared with the above-mentioned Embodiment 1. However, in Embodiment 4, as a trade-off with the improvement of the narrow viewing angle performance, in the wide viewing angle mode where it is not necessary to block the light 1LB in the oblique direction, the light may be blocked by the second electrode 232 (light absorbing material electrode) (see Fig. 8A (e)). In contrast, in the present embodiment, since the second electrode 232 (a laminate of a reflective material and a light absorbing material electrode) includes a reflective material, the light incident from the backlight source 40 to the overlapping region 241 (the switching region 243 in the low transmittance state) can be reflected toward the back side (the backlight source 40 side) by the reflective material. Furthermore, when the backlight source 40 has a reflective sheet, the reflected light from the reflective material can be reflected again toward the viewing side by the reflective sheet and reused as light incident to the non-overlapping region 242 (the transparent region 244) (see Fig.9A As a result, the light directly incident on the overlapping area 241 (the switching area 243 in the low transmittance state) which is desired to be blocked in the narrow viewing angle mode can be blocked, and the light can be converted (reused) into light in the front direction without waste. Therefore, in this embodiment, the brightness can be improved in both the wide viewing angle mode and the narrow viewing angle mode.

[0179] (Variation of Implementation Example 5)

[0180] In the above-mentioned Embodiment 5, the case where a laminate of a reflective material among electrodes containing a light absorbing material and a light absorbing material electrode is used as the second electrode 232 provided in the liquid crystal panel 20 is described, but a laminate of a reflective material, a light absorbing material layer, and a transparent electrode can also be used as the second electrode 232. In this modified example, as in the above-mentioned Embodiment 5, the narrow viewing angle performance is further improved, and by making the second electrode 232 contain a reflective material, the brightness can be improved in both the wide viewing angle mode and the narrow viewing angle mode.

[0181] As the reflective material, silver (Ag) is preferred as described above. As the light absorbing material layer, resin BM is preferred as described above. Therefore, as a laminate of the reflective material, the light absorbing material layer and the transparent electrode, a laminate in which resin BM and a transparent electrode (ITO, etc.) are laminated on silver is suitable. In this case, it is also suitable to configure the laminate in such a way that the reflective material is on the backlight source 40 side.

[0182] (Implementation 6)

[0183] In this embodiment, features unique to this embodiment are mainly described, and description of contents overlapping with those of the above-described Embodiment 1 is omitted. This embodiment is substantially the same as Embodiment 1 except that a backlight driven by local dimming is used as the backlight 40 .

[0184] Figure 1 , Figure 2A as well as Figure 2B The diagrams are a cross-sectional view of the image display device of the present embodiment, a cross-sectional view of the image display device of the present embodiment in a wide viewing angle mode, and a cross-sectional view of the image display device of the present embodiment in a narrow viewing angle mode. In the present embodiment, a backlight source driven by local dimming is used as the backlight source 40.

[0185] Local dimming drive refers to a function of dividing the image display area of ​​the display device into multiple areas (also called segments) and controlling the light for each area. If a backlight source driven by local dimming is used, the brightness of the backlight source can be locally controlled, thereby achieving high contrast and low power consumption of the display device. However, in general, in a display device that controls the viewing angle by a backlight source, it is difficult to take into account both viewing angle control and local dimming drive. In contrast, in the present invention, since the viewing angle can be controlled by the liquid crystal panel 20, the driving method of the backlight source is not selected. Therefore, it is very useful to be able to combine the liquid crystal panel 20 with a backlight source driven by local dimming.

[0186] (Implementation 7)

[0187] In this embodiment, features unique to this embodiment are mainly described, and description of contents overlapping with those in the above-described Embodiment 1 is omitted. This embodiment is substantially the same as Embodiment 1 except that the display panel 10 is a self-luminous display panel.

[0188] Fig.10 is a schematic cross-sectional view of the image display device involved in this embodiment. Fig.10 As shown, the image display device 1 of this embodiment includes a liquid crystal panel 20 and a self-luminous display panel as a display panel 10 for displaying an image. An adhesive layer 150 is usually provided between the display panel 10 and the liquid crystal panel 20 for attaching them. Since the image display device of this embodiment includes a self-luminous display panel as the display panel 10, a backlight source is not required.

[0189] As a self-luminous display panel, any self-luminous display panel is not particularly limited. For example, an organic electroluminescent (EL) display panel, a Micro-LED display panel using micron (μm) LEDs as RGB elements, etc. can be cited. In the present invention, the viewing angle can be controlled by the liquid crystal panel 20 regardless of whether there is a backlight source. Therefore, it is very useful to be able to combine the liquid crystal panel 20 with the self-luminous display panel.

[0190] As mentioned above, although embodiment of this invention was demonstrated, each matter demonstrated is all applicable to this invention as a whole.

[0191] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0192] (Example 1)

[0193] The image display device of Example 1 corresponds to the image display device of Embodiment 1 described above (see Figure 1 , Figure 2A , Figure 2B as well as Figure 5 The display panel 10 has a size of 11 inches, a resolution of full high definition (FHD), and a pixel pitch (the width of a pixel in the direction in which the gate line is extended × the width of a pixel in the direction in which the source line is extended) is set to 42 μm × 126 μm. Table 1 shows various design values ​​of the liquid crystal panel 20.

[0194] In the embodiments described below, unless otherwise specified, the display panel 10 and the backlight 40 are the same as those in Embodiment 1. The various designs and structures of the liquid crystal panel 20 are the same as those in Embodiment 1 unless otherwise specified.

[0195] [Table 1]

[0196]

[0197] In this embodiment, the first electrode 231 functions as a common electrode. The non-overlapping area 242 (mainly the transparent area 244) is controlled by the first electrode 231 and the third electrode 233, and the overlapping area 241 (mainly the switching area 243) is controlled by the first electrode 231 and the second electrode 232.

[0198] The image display device of this embodiment can cope with the usual liquid crystal process, does not produce moiré fringes, and has excellent viewing angle performance. In particular, on the basis of being able to achieve a wide viewing angle mode with high brightness, the thickness, weight and manufacturing cost of the image display device can be suppressed.

[0199] (Example 2)

[0200] The image display device of Example 2 also corresponds to the image display device of Embodiment 1, but in this example, the liquid crystal mode is set to the vertical alignment VA mode in the liquid crystal panel 20, and negative liquid crystal molecules are used to form the liquid crystal layer 240. A pair of polarizing plates 50 sandwiching the liquid crystal layer 240 are arranged in orthogonal Nicols. Fig.11A This is a schematic cross-sectional view for explaining the wide viewing angle mode in the image display device of this example. Fig. 11B is a cross-sectional schematic diagram for explaining the narrow viewing angle mode in the image display device of this example. Fig.11A and Fig. 11B In the figure, the display panel 10 is omitted for convenience.

[0201] like Fig.11A and Fig. 11B As shown, light is incident on the liquid crystal panel 20 from the back side (specifically, the backlight source 40). In a state where a voltage is applied between the first electrode 231 and the second electrode 232 (262), and a voltage is applied between the first electrode 231 and the third electrode 233 (261) (voltage applied state), the overlapping area 241 and the non-overlapping area 242 are not distinguished but integrated, and the entire liquid crystal layer 240 becomes a high transmission state (transparent area) (refer to Fig.11A That is, the transparent area 244 and the switching area 243 are in a state of having a transmittance T1. In this case, both the front light and the oblique light of the light incident on the liquid crystal panel 20 from the backlight source 40 directly pass through the liquid crystal panel 20 (see Fig.11A As a result, light from the back side (specifically, the backlight source 40 ) can be transmitted without loss from the low polar angle side to the high polar angle side, thereby realizing a wide viewing angle mode with high brightness.

[0202] On the other hand, in a state where no voltage is applied between the first electrode 231 and the second electrode 232 (262) and a voltage is applied between the first electrode 231 and the third electrode 233 (261) (no voltage applied state), the liquid crystal layer 240 itself functions as a barrier. That is, the light 1LB in the oblique direction of the light incident on the liquid crystal layer 240 from the backlight source 40 is shielded in the overlapping area 241 (switching area 243). Therefore, the overlapping area 241 (switching area 243) becomes a low-transmittance state, while the non-overlapping area 242 (transparent area 244) maintains a high-transmittance state. That is, it becomes a state where the transparent area 244 has a transmittance T2 and the switching area 243 has a transmittance T3 (where T1 ≥ T2 > T3). The light 1LA in the front direction of the light incident on the liquid crystal layer 240 from the backlight source 40 is transmitted through the liquid crystal panel 20 without attenuation (refer to Fig. 11BAs a result, on the high polar angle side, the light from the back side (specifically, the backlight source 40) is attenuated, and only on the low polar angle side can the light from the back side be transmitted with the original brightness, thereby achieving a narrow viewing angle mode.

[0203] Fig. 12A This is a waveform diagram of the voltage of each electrode when the image display device of this example is in the wide viewing angle mode (refer to Fig.11A ). Fig. 12B This is a waveform diagram of the voltage of each electrode when the image display device of this example is in the narrow viewing angle mode (refer to Fig. 11B ). I (231) is a waveform diagram of the voltage of the first electrode 231, II (232) is a waveform diagram of the voltage of the second electrode 232, and III (233) is a waveform diagram of the voltage of the third electrode 233. The horizontal axis represents time, and the vertical axis represents voltage (V). The driving voltage is not limited to the present voltage setting and can be set appropriately.

[0204] In this embodiment, the first electrode 231 (I) functions as a common electrode, and the non-overlapping area 242 (mainly the transparent area 244) is controlled by the first electrode 231 (I) and the third electrode 233 (III), and the overlapping area 241 (mainly the switching area 243) is controlled by the first electrode 231 (I) and the second electrode 232 (II).

[0205] The image display device of this embodiment can also cope with the usual liquid crystal process, does not produce moiré fringes, and has excellent viewing angle performance. In particular, on the basis of being able to achieve a wide viewing angle mode with high brightness, the thickness, weight and manufacturing cost of the image display device can be suppressed.

[0206] (Example 3)

[0207] The image display device of Example 3 corresponds to the image display device of Embodiment 2 described above (see Figure 6 ). In this embodiment, the switching region 243 is designed to be switched between a high transmission state and a low transmission state by applying or not applying a voltage between the first electrode 231 and the third electrode 233 (261) in the liquid crystal panel 20. In this embodiment, the overlapping region 241 is mainly a transparent region 244, and the non-overlapping region 242 is mainly a switching region 243.

[0208] (Examples 4-1, 4-2)

[0209] The image display device of Example 4-1 corresponds to the image display device of the above-mentioned Embodiment 3 (refer to Fig. 7A ), the image display device of Example 4-2 corresponds to the image display device of the modified example of the above-mentioned embodiment 3 (refer to Figure 7B ).like Fig. 7A (c) and Figure 7B As shown in (d), the third electrode 233 is formed by patterning.

[0210] The image display device of this embodiment can also cope with the usual liquid crystal process, does not produce moiré fringes, and has excellent viewing angle performance. In particular, on the basis of being able to achieve a wide viewing angle mode with high brightness, the thickness, weight and manufacturing cost of the image display device can be suppressed.

[0211] (Example 5)

[0212] The image display device of Example 5 corresponds to the image display device of the above-mentioned Embodiment 4 (refer to Fig. 8A and Figure 8B In this embodiment, a light absorbing material electrode (metal BM) is used as the second electrode 232 of the liquid crystal panel 20. In this embodiment, the narrow viewing angle performance is further improved compared with the first embodiment.

[0213] (Example 6)

[0214] The image display device of Example 6 corresponds to the image display device of the above-mentioned Embodiment 5 (refer to Fig.9A and Fig. 9B ). In this embodiment, a laminate of a reflective material and a light absorbing material electrode is used as the second electrode 232 of the liquid crystal panel 20. In this embodiment, the brightness is further improved in both the wide viewing angle mode and the narrow viewing angle mode compared to the first embodiment.

[0215] (Example 7)

[0216] The image display device of Example 7 corresponds to the image display device of the above-mentioned Embodiment 6. The structure of the image display device, the path of light in each viewing angle mode, etc. are referred to in Figure 1 , Figure 2A , Figure 2B as well as Figure 5 Even when a backlight source driven by local dimming is combined as in the present embodiment, it is possible to realize an image display device having excellent viewing angle performance while suppressing thickness, weight and manufacturing cost.

[0217] (Example 8)

[0218] The image display device of Example 8 corresponds to the image display device of Embodiment 7 described above (see Fig.10 ). Even when combined with a self-luminous display panel as in this embodiment, it is possible to realize an image display device that has excellent viewing angle performance while suppressing thickness, weight and manufacturing cost.

[0219] The above-described aspects of the present invention may be appropriately combined within the scope not departing from the gist of the present invention.

Claims

1. An image display device comprising a liquid crystal panel and a display panel for displaying an image, wherein the image display device is characterized in that: The liquid crystal panel includes a first transparent substrate, a first electrode, a liquid crystal layer, a second electrode, an interlayer insulating film, a third electrode and a second transparent substrate in order. The liquid crystal layer has an overlapping area overlapping with the second electrode and a non-overlapping area not overlapping with the second electrode, so that the liquid crystal layer has a transparent area and a switching area, the transparent area is an area having a high transmission state, and the switching area is an area that switches between a high transmission state and a low transmission state. The liquid crystal layer is sandwiched by a pair of polarizing plates.

2. The image display device according to claim 1, characterized in that: Different voltages can be applied to the transparent region and the switching region, respectively.

3. The image display device according to claim 1, characterized in that: The thickness of the non-overlapping region is 30 μm or less.

4. The image display device according to claim 1, characterized in that: The second electrode is a transparent electrode or an electrode including a light absorbing material.

5. The image display device according to claim 1, characterized in that: It also has a backlight.

6. The image display device according to claim 5, characterized in that: The backlight source has a local dimming function.

7. The image display device according to any one of claims 1 to 6, characterized in that: The display panel is a liquid crystal display panel or a self-luminous display panel.

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