KR102609771B1 - Transmissivity control device and liquid crystal display device using same - Google Patents

Abstract

The present invention is applicable to display device-related technical fields, and for example, relates to a transmittance control element and a liquid crystal display device capable of implementing local dimming using the same. The present invention provides a transmittance control element whose transmittance is adjusted in units of a certain area, including a first electrode having a pattern of unit electrodes having a certain area; a second electrode positioned at a predetermined distance from the first electrode; and a transmittance control material layer located between the first electrode and the second electrode.

Description

Transmittance control element and liquid crystal display device using the same {TRANSMISSIVITY CONTROL DEVICE AND LIQUID CRYSTAL DISPLAY DEVICE USING SAME}

The present invention is applicable to display device-related technical fields, and for example, relates to a transmittance control element and a liquid crystal display device capable of implementing local dimming using the same.

In general, among displays, liquid crystal displays (LCDs) are used in a variety of devices, including televisions, laptop computers, desktop computer monitors, and mobile phones.

Since the LCD cannot emit light on its own, a light-emitting device capable of illuminating the liquid crystal panel is required to display image information.

Since the light emitting device of the LCD is coupled to the back of the liquid crystal panel, it is called a backlight unit. This backlight unit can be said to be a device that provides a light source to the liquid crystal panel by forming a uniform surface light source.

This type of backlight unit provides a flat light source to the liquid crystal panel, so it can be viewed as an example of a flat lighting device. Such a flat lighting device is recognized as a light source that can radiate light uniformly through a flat surface and has a relatively thin thickness.

Recently, local dimming technology, which partially controls the brightness of the backlight unit, has been applied to improve contrast ratio when driving a liquid crystal display device.

However, as the number of unit blocks that control brightness increases to implement local dimming, limitations may arise. For example, when a backlight unit is implemented using a light emitting diode (LED), limitations may occur due to the size of the LED driver board, etc. This is because as the number of unit blocks of the local dimming block increases, the number of drivers may increase.

Meanwhile, in order to increase the number of unit blocks for local dimming, a separate mono panel can be attached behind the display panel (Dual Cell), or AM (active matrix) type mini LEDs can be separately implemented.

Among these, according to the method of attaching a separate mono panel behind the display panel (Dual Cell), a yield decrease may occur due to the attachment of two LCD panels. Additionally, under certain conditions (for example, 127 gray levels or higher), rainbow-colored spots may be recognized, and in some cases, a moiré phenomenon may occur.

On the other hand, when using AM mini LEDs, device handling may become difficult when applying a thin film transistor (TFT) substrate for AM implementation, and constant current control and current sensing of LEDs may be difficult. In addition, as the number of unit blocks for implementing local dimming increases, there is a problem in that the manufacturing cost increases.

Therefore, a method to solve the above problems and efficiently implement local dimming in a liquid crystal display device is required.

The purpose of the present invention is to provide a transmittance control element and a liquid crystal display device using the same to facilitate local dimming.

In addition, a transmittance control element capable of increasing the number of unit blocks for implementing local dimming and a liquid crystal display device using the same are provided.

In addition, the aim is to provide a transmittance control element that can be easily applied in the form of a sheet to a backlight system using an existing flat lighting device and a liquid crystal display device using the same.

Furthermore, the purpose of another embodiment of the present invention is to solve various problems not mentioned here. Those skilled in the art can understand the entire purpose of the specification and drawings.

As a first aspect for solving the above problem, the present invention provides a transmittance control element whose transmittance is adjusted in units of a certain area, comprising: a first electrode having a pattern of unit electrodes having a certain area; a second electrode positioned at a predetermined distance from the first electrode; and a transmittance control material layer located between the first electrode and the second electrode.

According to an exemplary embodiment, the unit electrode may define a unit area where transmittance is adjusted.

According to an exemplary embodiment, the first electrode may have a single-layer structure including a first conductive layer having the unit electrode surface.

According to an exemplary embodiment, the first electrode includes: a first conductive layer having the unit electrode surface; and a second conductive layer electrically connected to the first conductive layer.

According to an exemplary embodiment, an insulating layer may be positioned between the first conductive layer and the second conductive layer.

According to an exemplary embodiment, the first conductive layer and the second conductive layer may be electrically connected by a through electrode that penetrates the insulating layer.

According to an exemplary embodiment, the first conductive layer may include a transparent electrode layer.

According to an exemplary embodiment, the second conductive layer may include a mesh-shaped metal layer.

According to an exemplary embodiment, the second conductive layer may be connected to the first conductive layer to reduce electrical resistance of the first electrode.

According to an exemplary embodiment, the second conductive material may include a transparent conductive layer.

According to an exemplary embodiment, the transmittance control material layer includes at least one of Polymer Dispersed Liquid Crystal (PDLC), Guest-Host Liquid Crystal (G-H LC), Suspended Particle Device (SPD), or Electro-Chromic (EC). It can be included.

According to an exemplary embodiment, each unit electrode of the first electrode may be connected to a driving unit.

As a second aspect for solving the above problem, the present invention includes a flat lighting device; a transmittance control element located on the flat lighting device to adjust transmittance in units of a certain area; a liquid crystal display panel located on the transmittance control element; and an optical sheet positioned between the flat lighting device and the liquid crystal display panel, wherein the transmittance control element includes: a first electrode having a pattern of unit electrodes having a certain area; a second electrode positioned at a predetermined distance from the first electrode; and a transmittance control material layer located between the first electrode and the second electrode.

According to an exemplary embodiment, the transmittance control element may adjust the brightness of the flat lighting device in units of the certain area.

According to an exemplary embodiment, a diffusion sheet may be further included between the transmittance control element and the liquid crystal display panel.

According to an exemplary embodiment, the optical sheet may include a light diffusion plate.

According to an exemplary embodiment, the optical sheet may be positioned between the flat lighting device and the transmittance adjustment element.

According to an embodiment of the present invention, it is possible to enable multi-level gradation expression in a liquid crystal display device according to the characteristics of the electrochromic or transmittance control element itself.

In addition, local dimming can be implemented according to the size of the unit control area of the transmittance control element.

At this time, the moiré phenomenon can be prevented depending on the unit control area shape of the transmittance control element.

Additionally, the unit area for controlling the transmittance of this transmittance control element can be adjusted in various ways using the electrode shape and size. Therefore, local dimming of the liquid crystal display device can be easily implemented in multiple blocks. That is, the number of control blocks for local dimming can be easily increased, decreased, or adjusted.

In addition, local dimming operation and grayscale expression are possible in the transmittance control element. Accordingly, there may be no need to use a separate AM driven liquid crystal panel for local dimming operation and grayscale expression. Additionally, local dimming operation may not be implemented in a flat lighting device.

Furthermore, according to another embodiment of the present invention, there are additional technical effects not mentioned here. Those skilled in the art can understand the entire contents of the specification and drawings.

1 is an exploded perspective view showing a liquid crystal display device according to an embodiment of the present invention.
Figure 2 is a perspective view showing the transmittance adjustment element according to the first embodiment of the present invention.
Figure 3 is a plan schematic diagram showing the electrode pattern of the first electrode of the transmittance control element according to an embodiment of the present invention.
Figure 4 is a perspective view showing a transmittance control element according to a second embodiment of the present invention.
Figure 5 is a perspective view showing an example of a spacer used in the transmittance control element according to the second embodiment of the present invention.
Figure 6 is a perspective view showing examples of spacers of the transmittance control element of the present invention.
Figure 7 is a plan view showing the electrode pattern of the second electrode of the transmittance control element according to an embodiment of the present invention.
Figure 8 is a plan schematic diagram showing the electrode pattern of the second electrode of the transmittance control element according to an embodiment of the present invention.
Figure 9 is a perspective view showing a transmittance adjustment element according to a third embodiment of the present invention.
Figure 10 is a plan view showing an example of the first conductive layer of the transmittance control element according to the third embodiment of the present invention.
Figure 11 is a plan view showing an example of the second conductive layer of the transmittance control element according to the third embodiment of the present invention.
Figure 12 is a perspective view showing an example of a transmittance adjustment element according to a third embodiment of the present invention.
Figure 13 is a perspective view showing another example of the transmittance adjustment element according to the third embodiment of the present invention.
Figure 14 is an exploded perspective view showing a liquid crystal display device according to another embodiment of the present invention.
Figure 15 is a cross-sectional view showing a liquid crystal display device according to another embodiment of the present invention.
16 to 19 are cross-sectional schematic diagrams showing examples of transmittance adjustment elements that can be applied to an embodiment of the present invention.

Hereinafter, embodiments disclosed in the present specification will be described in detail with reference to the attached drawings. However, identical or similar components will be assigned the same reference numbers regardless of reference numerals, and duplicate descriptions thereof will be omitted. The suffixes “module” and “part” for components used in the following description are given or used interchangeably only for the ease of preparing the specification, and do not have distinct meanings or roles in themselves. Additionally, in describing the embodiments disclosed in this specification, if it is determined that detailed descriptions of related known technologies may obscure the gist of the embodiments disclosed in this specification, the detailed descriptions will be omitted. In addition, it should be noted that the attached drawings are only for easy understanding of the embodiments disclosed in this specification, and should not be construed as limiting the technical idea disclosed in this specification by the attached drawings.

Furthermore, although each drawing is described for convenience of explanation, it is within the scope of the present invention for a person skilled in the art to implement another embodiment by combining at least two or more drawings.

Additionally, when an element such as a layer, region or substrate is referred to as being “on” another component, it is to be understood that it may be present directly on the other element or that there may be intermediate elements in between. There will be.

The display device described in this specification is a concept that includes all display devices that display information using a unit pixel or a set of unit pixels. Therefore, it is not limited to finished products but can also be applied to parts. For example, a panel corresponding to a part of a digital TV also independently corresponds to a display device in this specification. Finished products include mobile phones, smart phones, laptop computers, digital broadcasting terminals, PDAs (personal digital assistants), PMPs (portable multimedia players), navigation, Slate PCs, Tablet PCs, and Ultra This may include books, digital TVs, desktop computers, etc.

However, those skilled in the art will easily understand that the configuration according to the embodiments described in this specification may be applied to a device capable of displaying, even if it is a new product type that is developed in the future.

1 is an exploded perspective view showing a liquid crystal display device according to an embodiment of the present invention.

Referring to Figure 1, an exploded view of a liquid crystal display device according to an embodiment of the present invention is schematically shown.

The liquid crystal display device 100 is largely comprised of a flat lighting device 110, a flat lighting device 110, a liquid crystal display panel 120, and a liquid crystal display panel 120 located between the flat lighting device 110 and the liquid crystal display panel 120. It may be configured to include an optical sheet 130.

At this time, a transmittance adjustment element 200 whose transmittance is adjusted in units of a certain area may be located between the flat lighting device 110 and the liquid crystal display panel 120.

The liquid crystal display panel 120 can implement a display using unit pixels of a display device. Although not separately shown, the liquid crystal display panel 120 may include a thin film transistor (TFT) and a curly filter for driving an active matrix (AM).

Accordingly, the liquid crystal display panel 120 can implement a full color display using the light emitted from the flat lighting device 110. In other words, the flat lighting device 110 can implement a liquid crystal display device together with the liquid crystal display panel 120. Hereinafter, detailed description of the liquid crystal display panel 120 will be omitted.

Meanwhile, the transmittance control element 200 can adjust the brightness of the flat lighting device 110 in units of a certain area. That is, the transmittance control element 200 can implement so-called local dimming, which can make a certain area of the liquid crystal display device 100 partially relatively dark.

This transmittance control element 200 may utilize electrochromism. This transmittance control element 200 can enable multi-level grayscale expression of the liquid crystal display device 100.

The shape of the unit control area of the transmittance control element 200 may be square. Local dimming can be implemented according to the size of this unit control area.

At this time, in order to prevent the Moire phenomenon, the shape of the unit control area may have the shape of a circle, diamond, grid, etc. as well as a square.

The unit area for controlling the transmittance of the transmittance control element 200 can be adjusted in various ways using the electrode shape and size. Therefore, local dimming of the liquid crystal display device 100 can be easily implemented in multiple blocks. That is, the number of control blocks for local dimming can be easily increased, decreased, or adjusted.

In addition, local dimming operation and grayscale expression are possible in the transmittance control element 200. Accordingly, there may be no need to use a separate AM driven liquid crystal panel for local dimming operation and grayscale expression. Additionally, local dimming operation may not be implemented in the flat lighting device 110.

The specific configuration and effects of the above transmittance control element 200 will be described in detail later.

Referring to FIG. 1, the optical sheet 130 may be positioned between the flat lighting device 110 and the transmittance adjustment element 200. However, the optical sheet 130 may be located between the transmittance control element 200 and the liquid crystal display panel 120. That is, the optical sheet 130 may be located on at least one side between the flat lighting device 110 and the transmittance adjustment element 200 and between the transmittance adjustment element 200 and the liquid crystal display panel 120.

Additionally, the optical sheet 130 can be used for various optical purposes, such as a light diffusion plate, diffusion sheet, etc. That is, the optical sheet 130 may include various functional layers.

Figure 2 is a perspective view showing the transmittance adjustment element according to the first embodiment of the present invention.

FIG. 2 may be a diagram illustrating a portion of the transmittance adjustment element 200 by way of example. Referring to FIG. 2, the transmittance control element 200 includes a first electrode 220 having a pattern of unit electrodes having a certain area, and a second electrode 210 located a certain distance away from the first electrode 220. and a transmittance control material layer 230 located between the first electrode 220 and the second electrode 210.

According to an exemplary embodiment, the unit electrode of the first electrode 220 may define a unit area whose transmittance is adjusted. That is, the area and shape of the unit electrode can define the unit area where the transmittance is adjusted. Accordingly, when the transmittance control element 200 is used together with the liquid crystal display panel 120, local dimming can be implemented on a per unit area basis.

According to an exemplary embodiment, the transmittance control material layer 230 is at least one of Polymer Dispersed Liquid Crystal (PDLC), Guest-Host Liquid Crystal (G-H LC), Suspended Particle Device (SPD), or Electro-Chromic (EC). It can contain one. In addition, of course, other material layers/devices can be used as long as they are materials or devices whose transmittance can be adjusted by an electric field.

The transmittance of the transmittance control material layer 230 can be adjusted by applying voltage or forming an electric field through the first electrode 220 and the second electrode 210.

The first electrode 220 may correspond to a lower electrode. That is, the first electrode 220 may be an electrode located on the side of the flat lighting device 110.

The second electrode 210 may correspond to an electrode located at a position where light is emitted, and may include a transparent electrode layer. This transparent electrode layer may include a transparent conductive oxide such as ITO (Indium Tin Oxide). This second electrode 210 may have an area corresponding to the pattern of the plurality of unit electrodes 221 (see FIG. 3) of the first electrode 220.

Meanwhile, the first electrode 220 may correspond to the lower electrode. In the transmittance control element 200, the second electrode 210 may be located on the opposite side of the first electrode 220. The first electrode 220 may correspond to an electrode close to a position where light emitted from the flat lighting device 110 is incident, and may include a transparent electrode layer. This transparent electrode layer may include a transparent conductive oxide such as ITO (Indium Tin Oxide).

Figure 3 is a plan schematic diagram showing the electrode pattern of the first electrode of the transmittance control element according to an embodiment of the present invention. The electrode pattern shown in FIG. 3 can be equally applied to other embodiments.

Figure 3 shows an exemplary embodiment of the first electrode 220. The first electrode 220 may include a pattern of multiple unit electrodes 221. 2 and 3 show the first electrode 220 having a single-layer structure. The first electrode 220 of this single-layer structure may include a transparent electrode layer.

Referring to FIG. 3, the first electrode 220 shows an example comprised of a plurality of square-shaped unit electrodes 221. However, this is only an example, and the shape, area, and arrangement of the first electrode 220 may be changed in various ways.

Each of the plurality of unit electrodes 221 may be connected to the driving unit 240 through a connection line 222. That is, the plurality of unit electrodes 221 constituting the first electrode 220 may be connected to one side by the connection line 222. These connection lines 222 may partially converge. The connection line 222 converged in this way can be connected to the driving unit 240. Here, the driver 240 may include a unit driver chip and, in some cases, may constitute a driver circuit.

A plurality of these unit electrodes 221 may have the same size and shape and be arranged on a plane. For example, the unit electrodes 221 may be arranged at regular intervals to form a pattern. As described above, the unit electrode 221 can be a control unit for local dimming. For example, the number of unit electrodes 221 may mean the number of control blocks for local dimming.

Figure 4 is a perspective view showing a transmittance control element according to a second embodiment of the present invention. Figure 4 shows the case where a liquid crystal-based material, such as Polymer Dispersed Liquid Crystal (PDLC) or Guest-Host Liquid Crystal (G-H LC), is used as the transmittance control material layer 230 of the transmittance control element 200. It shows an example.

Figure 5 is a perspective view showing an example of a spacer used in the transmittance control element according to the second embodiment of the present invention.

In this way, when a liquid crystal-based material is used as the transmittance control material layer 230, a spacer (spacer) 250 may be provided between the first electrode 220 and the second electrode 210. Figure 5 shows an example of a spacer 250 having a general cylindrical shape.

This spacer 250 can fix the gap between the first electrode 220 and the second electrode 210 and define the gap where the liquid liquid crystal-based material is located.

Meanwhile, in some cases, a spacer 250 may be provided between the first electrode 220 and the second electrode 210 even when a liquid crystal-based material is not used. For example, if the transmittance control material layer 230 is made of a material that is difficult to fix to a certain thickness, a spacer 250 may be provided.

Figure 6 is a perspective view showing examples of spacers of the transmittance control element of the present invention.

Figures 6(A) to 6(F) each show examples 251 to 256 of spacers that can be used in the transmittance adjustment element 200.

That is, Figure 6(A) shows a column-shaped spacer 251 with a trapezoidal cross-section. Figure 6(B) shows a cone-shaped spacer 252. Figure 6(C) shows a hemispherical spacer 253.

Additionally, Figure 6(D) shows a spacer 254 in the shape of a pentagonal pyramid. Figure 6(E) shows a spacer 255 in the shape of an inclined pentagonal pillar. Figure 6(F) shows a chestnut-shaped spacer 256.

As such, various types of spacers may be used depending on the characteristics of the applied display device.

Figure 7 is a plan view showing the electrode pattern of the second electrode of the transmittance control element according to an embodiment of the present invention.

Referring to FIG. 7, the first electrode 220 may have unit electrodes 221 arranged at regular intervals across the entire display surface. In Figure 7, the connection line and driving unit are omitted.

The total area of the second electrode 220 may correspond to the total area of the liquid crystal display panel 120. Additionally, the total area of the first electrode 220 corresponding to the first electrode 220 may also correspond to the total area of the liquid crystal display panel 120.

At this time, the area of the second electrode 210 may correspond to several unit electrodes 221. That is, the entire unit electrode 221 or a certain group of unit electrodes 221 may correspond to the area of the second electrode 210. For example, the second electrode 210 may correspond to a common electrode.

Figure 8 is a plan schematic diagram showing the electrode pattern of the second electrode of the transmittance control element according to an embodiment of the present invention. FIG. 8 shows another embodiment of the second electrode 220 corresponding to FIG. 3 described above.

Figure 8 shows an exemplary embodiment of the first electrode 220. The first electrode 220 may include a pattern of multiple unit electrodes 221.

Referring to FIG. 8, like the example of FIG. 3, the second electrode 220 is illustrated as an example of a plurality of square-shaped unit electrodes 221. However, this is only one example, and the shape, area, and arrangement of the second electrode 220 may be changed in various ways.

Each of the plurality of unit electrodes 221 may be connected to the driving unit 240 through a connection line 223. That is, the plurality of unit electrodes 221 forming the second electrode 220 may be connected to one side by the connection line 223. The unit electrodes 221 forming this group may converge toward the driver 240 by the connection line 223. The connection lines 223 converged in this way can be connected to the driving unit 240. Here, the driver 240 may include a unit driver chip and, in some cases, may constitute a driver circuit.

Figure 9 is a perspective view showing a transmittance adjustment element according to a third embodiment of the present invention.

The transmittance control element 200 according to the third embodiment may include a multi-layer second electrode 220a. The second electrode 220a may include a transparent electrode pattern and an electrode for improving conductivity. In other words, the second electrode 220a in such a multi-layer form may have the characteristic of reducing electrical resistance while maintaining transmittance.

Referring to FIG. 9, the transmittance control element 200 includes a first electrode 210 having a pattern of unit electrodes having a certain area, and a second electrode in the form of a multi-layer located at a certain distance from the first electrode 210. It may be configured to include (220a) and a transmittance control material layer 230 located between the first electrode 210 and the second electrode 220a.

When a liquid crystal-based material is used as the transmittance control material layer 230, a spacer 250 may be provided between the first electrode 210 and the second electrode 220.

Figure 10 is a plan view showing an example of the first conductive layer of the transmittance control element according to the third embodiment of the present invention. Additionally, Figure 11 is a plan view showing an example of the second conductive layer of the transmittance control element according to the third embodiment of the present invention.

According to an exemplary embodiment, the first electrode 220a includes a first conductive layer 224 having a unit electrode surface and a second conductive layer 226 electrically connected to the first conductive layer 224. It may be a two-layer structure.

The first conductive layer 224 and the second conductive layer 226 may be electrically connected to each other through the through hole 250. Additionally, an insulating layer may be positioned between the first conductive layer 224 and the second conductive layer 226.

Since the transmittance control element 200 must basically transmit light, the first electrode 220a may be an electrode that can transmit light. At this time, the first electrode 220a may include a first conductive layer 224, which is a transparent electrode, and a second conductive layer 226, which is a metal electrode.

That is, the second conductive layer 226, which is a metal electrode, can reduce the electrical resistance of the first electrode 220a. According to an exemplary embodiment, the second conductive layer 226 may be a metal electrode and may have a mesh shape capable of transmitting light. The second conductive layer 226 in the form of a mesh may be located on the first substrate 262, for example, the first PET film 262.

Figure 12 is a perspective view showing an example of a transmittance adjustment element according to a third embodiment of the present invention.

Referring to FIG. 12, an example of a transmittance control element 200 having a multi-layer first electrode 220a is shown.

The transmittance control element 200 having such a multi-layered first electrode 220a may have a second conductive layer 226, which is a metal electrode, positioned on a first substrate 262, for example, a first PET film 262. there is.

An insulating layer 227 may be located on the second conductive layer 226. The first conductive layer 224 may be located on the insulating layer 227. This first conductive layer 224 may correspond to the unit electrode 221 described above.

The second conductive layer 226 and the first conductive layer 224 may be electrically connected to each other by a through electrode 228.

The first conductive layer 224 may be a control unit for local dimming. For example, the number of first conductive layers 224 may mean the number of control blocks for local dimming.

A transmittance control material layer 230 may be located on the first conductive layer 224. The second electrode 210 may be located on the transmittance control material layer 230.

A second substrate 261, for example, a second PET film 262, may be positioned on the second electrode 210.

Figure 13 is a perspective view showing another example of the transmittance adjustment element according to the third embodiment of the present invention.

Referring to FIG. 13, another example of the transmittance control element 200 having a multi-layer first electrode 220a is shown.

The transmittance control element 200 having such a multi-layered first electrode 220a includes a transparent second conductive layer 226, which is a metal electrode, with a first substrate 262, for example, a first PET film 262 interposed therebetween. A first conductive layer 224, which is an electrode, may be located. This first conductive layer 224 may correspond to the unit electrode 221 described above.

An insulating layer 227 may be located below the second conductive layer 226. The first conductive layer 224 may correspond to the unit electrode 221 described above.

The second conductive layer 226 and the first conductive layer 224 may be electrically connected to each other by a through electrode 229 that penetrates the first substrate 262.

The first conductive layer 224 may be a control unit for local dimming. For example, the number of first conductive layers 224 may mean the number of control blocks for local dimming.

A transmittance control material layer 230 may be located on the first conductive layer 224. The second electrode 210 may be located on the transmittance control material layer 230.

A second substrate 261, for example, a second PET film 261, may be positioned on the second electrode 210.

Figure 14 is an exploded perspective view showing a liquid crystal display device according to another embodiment of the present invention. Additionally, Figure 15 is a cross-sectional view showing a liquid crystal display device according to another embodiment of the present invention.

The liquid crystal display device 100 is largely comprised of a flat lighting device 110, a flat lighting device 110, a liquid crystal display panel 120, and a liquid crystal display panel 120 located between the flat lighting device 110 and the liquid crystal display panel 120. It may be configured to include an optical sheet 130.

At this time, a transmittance adjustment element 200 whose transmittance is adjusted in units of a certain area may be located between the flat lighting device 110 and the liquid crystal display panel 120.

The optical sheet 130 may be positioned between the flat lighting device 110 and the transmittance adjustment element 200. According to this embodiment, a separate optical sheet 131 may be positioned between the transmittance adjustment element 200 and the liquid crystal display panel 120. This separate optical sheet 131 may be a diffusion sheet.

When forming the pattern of the unit electrodes 221 of the first electrode 220 as described above, a gap may exist between the unit electrodes 221. The gap between the unit electrodes 221 may be visible from the outside when the liquid crystal display device 100 is driven.

Therefore, it may be advantageous to provide a separate optical sheet, such as the diffusion sheet 131, on the transmittance control element 200. This diffusion sheet 131 can soften the light passing through the transmittance control element 200. In addition, the diffusion sheet 131 can ensure that the gap between the unit electrodes 221 is not visible. Meanwhile, this diffusion sheet 131 can prevent the Moire phenomenon.

Referring to FIG. 15, a plurality of optical sheets 133, 134, and 135 may be positioned between the flat lighting device 110 and the transmittance adjustment element 200. Additionally, an optical sheet 132 for other purposes may be positioned between the transmittance control element 200 and the liquid crystal display panel 120.

The liquid crystal display panel 120 may be positioned on the transmittance control element 200 with an air gap of a certain width.

The liquid crystal display panel 120 may have polarizers 122 and 123 located on both sides of the liquid crystal panel 121. That is, the liquid crystal panel 121 may be located on the lower polarizer 123, and the upper polarizer 122 may be located on the liquid crystal panel 121.

Other parts not described may be the same as those described above with reference to FIGS. 1 to 13, and therefore overlapping descriptions will be omitted.

16 to 19 are cross-sectional schematic diagrams showing examples of transmittance adjustment elements that can be applied to an embodiment of the present invention.

As described above, the transmittance control material layer 230 is made of at least one of Polymer Dispersed Liquid Crystal (PDLC), Guest-Host Liquid Crystal (G-H LC), Suspended Particle Device (SPD), or Electro-Chromic (EC). It can be included.

Table 1 summarizes the characteristics of PDLC, G-H LC (G/H LC), SPD, and EC.

According to an exemplary embodiment of the present invention, one of PDLC, G-H LC (G/H LC), SPD, and EC is used as the transmittance control material layer 230 depending on the conditions of the liquid crystal display device 100. Can be used optionally.

Figure 16 shows an example of PDLC. PLDC refers to a device that can control the degree of light scattering by changing the liquid crystal arrangement according to voltage.

In this PLDC, a polymer 231 material and a liquid crystal 233 may be located between the upper electrode film 232a and the lower electrode film 232b.

Here, the upper electrode film 232a and the lower electrode film 232b may correspond to the second electrode 210 and the first electrode 220 described above. Additionally, it may be a separate component added to the second electrode 210 and the first electrode 220.

In PLDC, light can be blocked (light blocking) if liquid crystal droplets are randomly oriented. That is, PLDC may be a scattering light blocking method (Milky White).

Meanwhile, when an electric field is applied by the upper electrode film 232a and the lower electrode film 232b, the liquid crystal is vertically aligned according to the electric field and can become transparent (light transmission).

Figure 17 shows an example of G-H LC (G/H LC). G-H LC can be transparent and light-blocking by the operation of liquid crystal mixed with dye (Haze-zero mode).

In this G-H LC, a polymer 231 material, a liquid crystal 233, and a dye 235 may be located between the upper electrode film 232a and the lower electrode film 232b.

Although not separately shown, an alignment film may be provided on the upper electrode film 232a and the lower electrode film 232b.

In G-H LC, light can be absorbed (light blocking) by dye mixed in horizontally aligned liquid crystals. Additionally, uniaxial light may be absorbed by dye mixed in vertically aligned liquid crystals (light transmission as minimum absorption).

Figure 18 shows an example of SPD. In SPD, the degree of light absorption can be adjusted by changing the arrangement of particles depending on voltage.

In this SPD, the polymer 231 and the microcapsule 236 may be located between the upper electrode film 232a and the lower electrode film 232b. Metal particles may be located in the microcapsule 236.

In SPD, dipole particles in the microcapsule 236 are organically polarized by the application of an external voltage applied through the upper electrode film 232a and the lower electrode film 232b, thereby turning light on/off ( Off) can be adjusted.

Figure 19 shows an example of EC. EC can control light absorption through electron transfer due to oxidation/reduction of materials.

In this EC, the solid electrolyte 239 may be located between the upper electrode film 232a and the lower electrode film 232b. An inorganic discoloration (electro-chromic) portion may be located between the solid electrolyte 239 and the lower electrode film 232b.

In EC, light absorption can be controlled according to changes in the electronic state of the material (electron movement due to oxidation/reduction).

According to the above-described embodiment of the present invention, it is possible to enable multi-level grayscale expression of the liquid crystal display device 100 according to the characteristics of the electrochromic or transmittance control element 200 itself.

Local dimming can be implemented according to the size of the unit control area of the transmittance control element 200.

At this time, the moiré phenomenon can be prevented depending on the unit control area shape of the transmittance control element 200.

The unit area for controlling the transmittance of the transmittance control element 200 can be adjusted in various ways using the electrode shape and size. Therefore, local dimming of the liquid crystal display device 100 can be easily implemented in multiple blocks. That is, the number of control blocks for local dimming can be easily increased, decreased, or adjusted.

In addition, local dimming operation and grayscale expression are possible in the transmittance control element 200. Accordingly, there may be no need to use a separate AM driven liquid crystal panel for local dimming operation and grayscale expression. Additionally, local dimming operation may not be implemented in the flat lighting device 110.

100: liquid crystal display device
110: Flat lighting device
120: liquid crystal display panel
200: Transmittance control element
210: second electrode
220: first electrode 221: unit electrode
222, 223: connection line 224: first conductive layer
226: second conductive layer 227: insulating layer

Claims (20)

In the transmittance control element whose transmittance is adjusted in units of a certain area,
a first electrode having a pattern of unit electrodes having a certain area;
a second electrode positioned at a predetermined distance from the first electrode; and
It includes a transmittance control material layer located between the first electrode and the second electrode,
The first electrode is,
a first conductive layer having a pattern shape of the unit electrode; and
A transmittance control element comprising a second conductive layer electrically connected to the first conductive layer. The transmittance control element according to claim 1, wherein the unit electrode defines a unit area where transmittance is adjusted. delete delete The transmittance control element according to claim 1, wherein an insulating layer is positioned between the first conductive layer and the second conductive layer. The transmittance control element according to claim 5, wherein the first conductive layer and the second conductive layer are electrically connected to each other by a through-electrode penetrating the insulating layer. The transmittance control element according to claim 1, wherein the first conductive layer includes a transparent electrode layer. The transmittance control element according to claim 1, wherein the second conductive layer includes a mesh-shaped metal layer. The transmittance control element of claim 1, wherein the second conductive layer is connected to the first conductive layer to reduce electrical resistance of the first electrode. The transmittance control element according to claim 1, wherein the second conductive layer includes a transparent conductive layer. The method of claim 1, wherein the transmittance control material layer includes at least one of Polymer Dispersed Liquid Crystal (PDLC), Guest-Host Liquid Crystal (G-H LC), Suspended Particle Device (SPD), or Electro-Chromic (EC). A transmittance control element characterized in that. The transmittance control element according to claim 1, wherein each unit electrode of the first electrode is connected to a driving unit. flat lighting device;
a transmittance control element located on the flat lighting device to adjust transmittance in units of a certain area;
a liquid crystal display panel located on the transmittance control element; and
It is configured to include an optical sheet positioned between the flat lighting device and the liquid crystal display panel,
The transmittance control element is,
a first electrode having a pattern of unit electrodes having a certain area;
a second electrode positioned at a predetermined distance from the first electrode; and
It is composed of a layer of transmittance control material located between the first electrode and the second electrode,
A liquid crystal display device, wherein the transmittance control element partially renders a certain area of the liquid crystal display panel relatively dark. The liquid crystal display device of claim 13, wherein the transmittance control element adjusts the brightness of the flat lighting device in units of the constant area. The liquid crystal display device of claim 13, further comprising a diffusion sheet between the transmittance control element and the liquid crystal display panel. The liquid crystal display device of claim 13, wherein the optical sheet includes a light diffusion plate. The liquid crystal display device of claim 13, wherein the optical sheet is positioned between the flat lighting device and the transmittance control element. The method of claim 13, wherein the first electrode is:
a first conductive layer having a pattern shape of the unit electrode; and
A liquid crystal display device characterized in that it has a multi-layer structure including a second conductive layer electrically connected to the first conductive layer. The method of claim 13, wherein the transmittance control material layer includes at least one of Polymer Dispersed Liquid Crystal (PDLC), Guest-Host Liquid Crystal (G-H LC), Suspended Particle Device (SPD), or Electro-Chromic (EC). A liquid crystal display device characterized in that. The liquid crystal display device of claim 13, wherein each unit electrode of the first electrode is connected to a driving unit.