KR102418919B1 - Display panel with mirror and display device comprising thereof - Google Patents

Abstract

The present invention relates to a mirror display panel and a display device including the same, wherein the display panel according to an embodiment of the present invention reflects external light using a polarizing layer and a reflective layer, but controls the color of the reflected light to achieve a color mode and a mirror mode, and a display device according to an embodiment of the present invention includes a first display panel that provides an image, and a second display panel that displays an image by polarizing external light or reflects external light .

Description

Mirror display panel and display device including same

The present invention relates to a mirror display panel and a display device including the same.

A display device (display device) is a device that visually displays data, and includes a liquid crystal display, an electrophoretic display, an organic light emitting display, an inorganic EL display, (Electro Luminescent Display), Field Emission Display, Surface-conduction Electron-emitter Display, Plasma Display, and Cathode Ray, Display ), etc.

Among these, liquid crystal display (LCD) has been in the spotlight in recent years due to the advantages of mass production technology, ease of driving means, realization of high quality, and realization of a large screen.

A liquid crystal display device (LCD) is an electronic device that converts various types of electrical information generated in various devices into visual information by using a change in liquid crystal transmittance according to an applied voltage. The liquid crystal display device can realize low power driving, a thin structure, and excellent image quality, and thus is widely used as an alternative means to overcome the disadvantages of the conventionally used cathode ray tube (CRT).

On the other hand, a digital paper display device (Digital Paper Display Device) is a display device that displays characters, symbols, or pictures using the electrophoretic principle, characterized in that it consumes little power.

Such display devices may be largely divided into a display panel (display unit), a circuit unit, and a backlight unit. The display unit controls the amount of transmitted light to display an image, and the circuit unit applies various signals transmitted from the driving system to the display panel (display unit) and controls these signals. , the backlight unit is used as a dimming device that evenly irradiates light to the entire display panel.

Specifically, the display panel is made of a liquid crystal interposed between two opposing substrates, and an image is displayed by changing the arrangement of the liquid crystal by an electric field generated with the liquid crystal interposed therebetween. A polarizing plate is attached to the outside of the two substrates, respectively.

The circuit unit includes various circuit elements and a printed circuit board (PCB) to control the overall driving of the liquid crystal display device.

A backlight unit (BLU) is a light source of a liquid crystal display, and is a light supply device provided because the liquid crystal display does not emit light by itself and is a light-receiving element that displays an image by controlling the transmittance of light coming from the outside.

That is, the liquid crystal display device includes a liquid crystal panel in which a plurality of pixels are arranged in a matrix, a driving circuit for driving the liquid crystal panel, and a backlight unit for irradiating light to the liquid crystal panel. Quality is being improved to cope with low power consumption.

When a backlight unit or a lamp is combined without using external light in implementing the above-described liquid crystal display device, digital paper display device, etc., the thickness of the display device increases and power consumption increases. In particular, the backlight unit or lamp may not be necessary according to characteristics of an image or image to be provided by the display device and an area in which the display device should be located.

However, if the backlight unit or lamp is not coupled, the display device must use external light. In particular, when a display device provides various functions, such as a mirror, a new display device structure is required.

Accordingly, an object of the present invention is to present a mirror display panel that provides a mirror-like function while using external light and a display device including the same.

The present invention provides a display panel and a display device that reflect external light and display an image using the reflected light as a light source.

The present invention provides a display panel and a display device that selectively control the reflection of external light to provide a mirror mode for reflecting external light as it is and a color mode for outputting an image.

The present invention provides a display panel and a display device that provide a mirror mode and a color mode without a separate light source or using only a light source with a small amount of power.

A display panel according to an embodiment of the present invention includes a display panel that reflects external light using a polarizing layer and a reflective layer, and implements a color mode and a mirror mode by controlling the color of the reflected light.

A display panel according to another embodiment of the present invention includes a dichroic color filter including a dye in reactive mesogen (RM).

A display panel according to another embodiment of the present invention includes a display panel for vertically or horizontally controlling an optical axis of a dichroic color filter and an optical axis of polarized light reflected.

A display device according to an embodiment of the present invention includes a first display panel that provides an image, and a second display panel that displays an image by polarizing external light or reflects external light.

A display device according to another embodiment of the present invention includes a first substrate on which a reflective layer and a polarizing layer are disposed, a second substrate on which a dichroic color filter is disposed, and a controller for controlling reflection or color conversion of external light.

When the present invention is applied, the present invention can implement a display panel and a display device that reflects external light and displays an image using the reflected light as a light source.

When the present invention is applied, the present invention can implement a display panel and a display device that selectively control the reflection of external light to provide a mirror mode for reflecting external light as it is and a color mode for outputting an image.

When the present invention is applied, it is possible to implement a display panel and a display device that provide various information even on the rear surface of the mobile device by providing a thin second display panel to a device such as a mobile device.

When the present invention is applied, a display panel and a display device that provide a mirror mode and a color mode can be implemented without a separate light source or using only a light source with a small amount of power.

1 is a diagram illustrating a configuration of a display panel provided with a passive mirror function.
2 is a diagram illustrating a configuration of a display panel provided with a mirror function.
3 is a view showing the configuration of a mirror display panel according to an embodiment of the present invention.
4 is a diagram showing a configuration for implementing a color mode according to an embodiment of the present invention.
5 is a diagram showing the configuration of a display panel implementing a mirror mode according to another embodiment of the present invention.
6 is a view showing a display panel to which a black dye is bonded according to another embodiment of the present invention.
7 is a diagram illustrating a configuration of a display panel in which a white sub-pixel does not have a separate white dye and a color filter including an empty space is combined according to another embodiment of the present invention.
8 is a view showing a display panel without white sub-pixels according to another embodiment of the present invention.
9 is a view showing the configuration of a dichroic color filter according to an embodiment of the present invention.
10 is a view showing a position of a second reflective layer according to an embodiment of the present invention.
11 is a view showing a position of a second reflective layer according to another embodiment of the present invention.
12 is a diagram illustrating a display device operating in an off mode according to an embodiment of the present invention.
13 is a view showing a display device operating in a mirror mode according to another embodiment of the present invention.
14 is a diagram illustrating a display device operating in a color mode according to another embodiment of the present invention.
15 is a view showing a display device according to an embodiment of the present invention.
16 is a diagram illustrating components of a display device according to an embodiment of the present invention.
17 is a display device according to another embodiment of the present invention.

Hereinafter, with reference to the drawings, embodiments of the present invention will be described in detail so that those of ordinary skill in the art to which the present invention pertains can easily implement them. The present invention may be embodied in many different forms and is not limited to the embodiments described herein.

In order to clearly explain the present invention, parts irrelevant to the description are omitted, and the same reference numerals are assigned to the same or similar components throughout the specification. Further, some embodiments of the present invention will be described in detail with reference to exemplary drawings. In adding reference numerals to components of each drawing, the same components may have the same reference numerals as much as possible even though they are indicated in different drawings. In addition, in describing the present invention, if it is determined that a detailed description of a related known configuration or function may obscure the gist of the present invention, the detailed description may be omitted.

In the following, the provision or arrangement of an arbitrary component on the “upper (or lower)” or “top (or below)” of the substrate means that any component is provided or disposed in contact with the upper surface (or lower surface) of the substrate. It is not intended to mean, but is not limited to, the inclusion of other components between the substrate and any component provided or disposed on (or under) the substrate. In addition, in describing the components of the present invention, terms such as first, second, A, B, (a), (b), etc. may be used. These terms are only for distinguishing the elements from other elements, and the essence, order, order, or number of the elements are not limited by the terms. When it is described that a component is “connected”, “coupled” or “connected” to another component, the component may be directly connected or connected to the other component, but other components may be interposed between each component. It should be understood that each component may be “interposed” or “connected”, “coupled” or “connected” through another component.

The display device outputs image data provided from the outside using various light sources. In this process, the image data is divided into R (red), G (green), and B (blue) and provided to the display device, and may optionally include W (white) or Black (black). Meanwhile, in addition to the image, the display device may provide various functions. In particular, when a mirror function is added to the display device, an external object can be illuminated like a mirror.

1 is a diagram illustrating a configuration of a display panel provided with a passive mirror function.

A thin film transistor 15 , a light transmitting layer 16 , and a color filter 17 are disposed between the first substrate 14 and the second substrate 18 , and the first polarized light is disposed on the lower surface of the first substrate 14 . A second polarizing layer 19 for reflecting external light is disposed on the upper surface of the layer 12 and the second substrate 18 . And the backlight unit 10 is disposed.

The structure shown in FIG. 1 is an embodiment of a passive mirror display panel, in which a reflective polarizing layer (or M-Pol) is disposed on the second substrate 18 instead of the conventional polarizing layer. . Unlike the structure of FIG. 1 , a general polarization layer may be disposed on the upper surface of the second substrate 18 and a reflective layer (DBEF Core) may be added.

Meanwhile, in the active mirror display panel, a cell for controlling the specular reflectance of the mirror may be added in addition to the structure of FIG. 1 .

2 is a diagram illustrating a configuration of a display panel provided with a mirror function.

Cells 21, 23, and 25 for controlling the mirror's specular reflectance are added on the second polarizing layer 19 that reflects external light.

In more detail, in order to implement an active mirror display device, the cells 23 between the first cell substrate 21 and the second cell substrate 25 include PDLC (Polymer Dispersed Liquid Crystals) for scattering-transmission and absorption-transmission. Electro-Chromic (EC) or absorption-transmitting cells for controlling polarization, scattering-transmitting CLC (Cholesteric Liquid Crystal), and the like may be disposed. PDLC is manufactured by mixing a liquid crystal with a monomer and injecting it between transparent electrodes, and the transmission scattering principle can be used. EC (Electro-Chromic) uses the principle that an electrochromic element (Metal) is oxidized/reduced when a voltage is applied, and the color is changed through this to transmit/absorb. The polarization control cell transmits or blocks reflected light through interaction with the polarization layer disposed on the upper surface of the lower LCD using a liquid crystal cell (LC Cell) with a polarizer attached thereto. CLC uses the principle of scattering transmission by the helix structure of CLC. In the case of GHLC, which is doped with color dye to realize the color of the back of the mobile phone, a specific color is mixed with the liquid crystal and then injected between the transparent electrodes.

On the other hand, in order to implement a color variable structure by disposing a separate display panel on the back surface of a tablet or mobile phone, the cell 23 between the first cell substrate 21 and the second cell substrate 25 is A Guest-Host Liquid Crystal Composition (GHLC) for color variation may be disposed.

In order to implement a display panel providing a mirror function as shown in FIGS. 1 and 2 , the backlight unit 10 is absolutely necessary.

However, when the backlight unit 10 is included, since there are problems such as thickness, outdoor visibility, and additional use of power, a mirror display device using external light can be configured without the backlight unit.

In addition, in order to implement switching between the mirror mode and the color mode, it is necessary to add separate cells 21 , 23 , 25 and the like for controlling the polarization shown in FIG. 2 .

The above-described method increases the driving voltage, thickness, and cost, and there has been a problem in that only a single color is possible.

3 is a view showing the configuration of a mirror display panel according to an embodiment of the present invention.

3 shows a first substrate 301 on which a thin film transistor 305 is disposed, a second substrate 309 on which a dichroic color filter 307 is disposed, and a light transmitting layer 306 disposed therebetween. And in an embodiment, the polarization layer 320 and the first reflection layer 310 are disposed on the other surface of the first substrate 301 . The polarization layer 320 may be a reflective polarization layer having reflective properties as an embodiment. The first reflective layer 310 recycles the light passing through the polarization layer 320 and reflects it back to the polarization layer 320 .

An embodiment of the light-transmitting layer 306 is a liquid crystal layer, and the phase of the liquid crystal of the light-transmitting layer 306 is changed under the control of the thin film transistor 305 to change light. In addition, the color filter 307 according to an embodiment of the present invention is a dichroic color filter arranged in a predetermined direction as an embodiment. The color filter 307 is a dichroic color filter having anisotropy and may be formed by combining reactive mesogen (RM), which is a reactive liquid crystal monomer, and a dye for a specific color.

In FIG. 3 , the color filter 307 constitutes RGB and W, and W includes a white dye according to an embodiment. Another embodiment includes an embodiment in which a separate color filter dye is not disposed in the W subpixel region. In another embodiment, in W, a color filter of a specific color may be finely arranged to implement light colors (light red, light blue, light green, etc.) in consideration of the characteristics of reflected light. In addition, in order to increase the reflectivity in the mirror mode, an empty space such as 390 may be placed between each color. In another embodiment, the color filter may be configured so that there is no empty space except for the W area.

The first reflective layer 310 located on the other surface of the first substrate 301 reflects light incident from the outside, and the polarization layer 320 polarizes the reflected light to pass through the light transmitting layer 306 . Therefore, color can be realized by driving the thin film transistor 306 or a mirror mode can be implemented.

Meanwhile, the second reflective layer 330 may be disposed on the W subpixel. This is applied to increase the reflectance of external light in the mirror mode.

In the configuration of FIG. 3 , when the color mode is implemented, the light reflected from the outside passes through the polarization layer 320 after being reflected by the first reflective layer 310 and transmits the light whose phase is changed according to RGB information to the thin film transistor 305 Light is selectively transmitted through the light-transmitting layer 306 such as the liquid crystal layer under the control of the color filter 307, and the color of the transmitted light is changed and passed through the color filter 307 to implement a color. As a result, an effect of outputting a specific image or video is provided. This can increase the convenience of use by outputting specific information, for example, time, text, etc., through the display panel on the rear side and not driving the display panel on the front side.

When the mirror mode is implemented in the configuration of FIG. 3 , the light reflected from the outside passes through the polarization layer 320 after being reflected by the first reflection layer 310 , and after the light whose phase is changed passes through the light transmission layer 306 . , passes through the color filter 307 without changing the color and reflects the external light. The first reflective layer 310 for the light reflection effect can reduce the thickness of the entire display panel in that it does not require a separate external light, and also recycles and reflects the light transmitted from the polarization layer 320 , so a mirror effect is obtained. can increase

In addition, in the mirror mode, the second reflective layer 330 may further enhance the reflective effect of external light. The second reflective layer 330 may be selectively added according to the total reflectance, and an area occupied by the second reflective layer 330 in the entire display panel may be adjusted to increase or decrease the external light reflection effect. This may be selectively arranged in consideration of visibility in the mirror mode and the color mode. In addition, the width and position of the empty space 390 through which external light is transmitted without color in the color filter may be included in various ways.

The above-described color mode and mirror mode may operate identically in all sub-pixels constituting the display panel or may operate differently for individual sub-pixels. Accordingly, the display panel may operate in the color mode in some areas and in the mirror mode in other areas.

In summary, in the configuration of FIG. 3 , the first thin film transistor 305 for controlling the light transmitting layer 306 is disposed on one surface of the light transmitting layer 306 centered on the light transmitting layer 306 and for controlling the light transmitting layer 306 for each sub-pixel. The second substrate 309 is disposed to face the first substrate 301 based on the substrate 301 and the light transmitting layer 306 and the dichroic color filter is disposed, and is disposed outside the first substrate 301 . It is composed of a polarization layer 320 that polarizes the light incident from the second substrate 309 and a first reflection layer 310 that reflects the incident light.

In one embodiment, as shown in FIG. 3 , the first reflective layer 310 , the polarizing layer 320 , the first substrate 301 , the light transmitting layer 306 , the dichroic color filter 307 , and the second substrate 309 are They may be sequentially stacked, and the polarization layer 320 and the first reflective layer 310 may be disposed on the outer surface of the first substrate 301 to increase the efficiency of the process. That is, the durability of the polarization layer 320 can be improved by disposing the polarization layer 320 after a high-temperature process of disposing a thin film transistor or the like on the first substrate 301 is performed.

Meanwhile, unlike the configuration of FIG. 3 , the polarization layer 320 may be disposed in various positions. In another embodiment, after being disposed to have heat resistance on the first substrate 301 , the thin film transistor 305 may be disposed thereon to increase polarization efficiency. In another embodiment, it may be disposed between the second substrate 309 and the color filter 307 . When the polarization layer 320 is disposed in various positions, it may be formed of an Ag wire having heat resistance.

Referring to FIGS. 4 and 5 for a more detailed operation configuration.

4 is a diagram showing a configuration for implementing a color mode according to an embodiment of the present invention. As described above, the color mode may be applied to the entire display panel or may be applied only to a portion of the display panel. This may be implemented for each sub-pixel under the control of the thin film transistor 305 .

The polarization layer 320 has a property of polarizing light and a property of transmitting light. Accordingly, the light 410a that has passed through the polarization layer 320 from the outside light is reflected from the first reflective layer 310 , is incident on the polarization layer 320 , is polarized, and then passes through the light transmission layer 306 . The light 420a reflectively polarized by the polarization layer 320 also passes through the light transmission layer 306 . For example, when the polarization layer 320 has a light reflectivity of 60% and a transmittance of 40%, 410a may account for 40% of external light and 420a may account for 60% of external light.

The two types of reflectively polarized lights 410a and 420a have a phase delay according to the driving shape of the liquid crystal under the control of the thin film transistor 305 . That is, when the optical axis of the phase-delayed light passing through the light transmitting layer 306 coincides with the absorption axis of the color filter 307, it has a specific color as shown in 430a. In this case, the specular reflectance of the mirror is also reduced, so that the mirror function is not performed. As a result, a specific image can be displayed. Reference numeral 401 indicates the transmission axis of the polarization layer 320 , 402 indicates the absorption axis of the first substrate 301 , and 403 indicates the absorption axis of the color filter 307 .

5 is a diagram showing the configuration of a display panel implementing a mirror mode according to another embodiment of the present invention. As described above, the mirror mode may be applied to the entire display panel or may be applied only to a portion of the display panel. This may be implemented for each sub-pixel under the control of the thin film transistor 305 .

The polarization layer 320 has a property of polarizing light and a property of transmitting light. Accordingly, the light 410b that has passed through the polarization layer 320 from the outside light is reflected from the first reflective layer 310 , is incident on the polarization layer 320 , is polarized, and then passes through the light transmission layer 306 . The light 420b reflectively polarized by the polarization layer 320 also passes through the light transmission layer 306 . For example, when the polarization layer 320 has a light reflectance of 60% and a transmittance of 40%, 410b may account for 40% of external light and 420b may account for 60% of external light.

The two types of reflected polarized lights 410b and 420b have a phase delay according to the driving shape of the liquid crystal under the control of the thin film transistor 305 . That is, when the optical axis of the phase-delayed light passing through the light transmitting layer 306 has the same shape as 503 and is perpendicular to the absorption axis 403 of the color filter 307, the two types of reflected and polarized light 410b and 420b ) is transmitted to the outside like 430b. At this time, since the light transmitted to the outside is transmitted perpendicularly to the absorption axis 403 of the color filter 307 , it does not have a separate color. As a result, the specular reflectance of the mirror can be increased.

In the configuration of FIGS. 3, 4 and 5 , the polarization layer 320 is disposed between the first substrate 301 and the thin film transistor 305 or between the second substrate 309 and the color filter 307 . as an example. In this case, the polarization layer 320 may be formed of a wire having heat resistance. For example, a silver wire (Ag Wire) is used as an embodiment.

6 is a view showing a display panel to which a black dye is bonded according to another embodiment of the present invention. In FIG. 6 , a black dye 607 may be disposed to display black color, and a spectrum of colors that can be displayed using the black sub-pixels may be varied to broaden the range of color expression.

7 is a diagram illustrating a configuration of a display panel in which a white sub-pixel does not contain a separate white dye and a color filter including an empty space is combined according to another embodiment of the present invention. In the color filter 307b of FIG. 7 , a separate dye is not mounted in the W sub-pixel region and may be configured as an empty space like 701a. In addition, empty spaces 701b and 701c in which a dye is not disposed may be disposed between each sub-pixel in order to reinforce the mirror function. A second reflective layer 330b may be disposed to correspond to the W sub-pixel area. In another embodiment, the second reflective layer 330b may be disposed in the W subpixel region 701a in FIG. 7 .

8 is a view showing a display panel without white sub-pixels according to another embodiment of the present invention. In the color filter 307c, RGB of a dichroic dye is arranged for each sub-pixel.

6 to 8 , the colors of various sub-pixels and color filters may be configured, which are the reflectance and transmittance of the polarizing layer constituting the display panel, and the mode to be operated more importantly in the mirror mode and the color mode. It can be configured in various ways according to the characteristics of , and in particular, it enables the realization of a color mode using external light through a dichroic color filter.

9 is a view showing the configuration of a dichroic color filter according to an embodiment of the present invention.

As described above, the dichroic color filter includes RM, which is a reactive liquid crystal monomer. When the color filter 907 is enlarged in FIG. 9 , it is the same as 910 . The reactive liquid crystal monomer 930 and the dichroic dyes 920r, 920b, and 920g of each color are disposed in the color region of each subpixel. The R subpixel area 910r, the G subpixel area 910g, the B subpixel area 910b, and the W subpixel area 910w are the same when the embodiment in which no dye is applied is applied.

As shown in FIG. 9, a dichroic color filter can be implemented by combining a color dye and RM. The dichroic color filter transmits the polarized light as it is, or transmits the light by converting it to have a specific color through color conversion, so that a mirror mode and a color mode can be implemented.

As described above, the second reflective layer is disposed to increase external light reflection in the mirror mode. Accordingly, it may be disposed to correspond to the area of the W subpixel instead of being disposed on the entire surface. In addition, the second reflective layer may be disposed in various ways according to the configuration of the W sub-pixel. In addition, the second reflective layer does not necessarily have to be disposed in all W sub-pixels, but may be disposed only in some W sub-pixel areas according to a configuration.

10 is a view showing a position of a second reflective layer according to an embodiment of the present invention. A second substrate (not shown) may be disposed on the color filter 1007 , and a second reflective layer such as 1030a, 1030b, or 1030c may be disposed on the second substrate.

11 is a view showing a position of a second reflective layer according to another embodiment of the present invention. When the RWGB sub-pixel area is configured as a grid, the second reflective layer may be disposed as shown in 1130 in correspondence with the W sub-pixel area.

An embodiment of the present invention is a color filter composed of a dichroic dye aligned in one direction by RM or an alignment layer, a reflective polarizing layer (Mirror Pol), and a reflective layer including a material that reflects light such as aluminum, and white By selectively including sub-pixels, the reflectance in mirror mode is maximized.

A principle of implementing a color mode according to an embodiment of the present invention is the same as described in FIGS. 4 and 5 . That is, the light source incident from the outside is reflectively polarized by the reflective polarization layer 302 , and the reflectively polarized light source causes a phase delay according to the driving shape of the liquid crystal of the light transmitting layer 306 . At this time, when the optical axis coincides with the absorption axis of the R, G, and B dyes of the color filter 307, a specific color is obtained, and the mirror's specular reflectance is also reduced, making the mirror function impossible.

The light source that has passed through the reflective polarization layer 320 is recycled by a reflective layer 310 disposed below the reflective polarization layer 320 , for example, a layer that reflects light such as an aluminum layer. In addition, by using the thin film transistor 305, the grayscale expression of the reflected light source can be controlled, and it can also serve as a display element. In the mirror mode, a phase delay occurs in the direction of vibration of the polarized light source reflected by the reflective polarizing layer and the reflective layer (aluminum layer) by the liquid crystal, and the light source absorbs the R, G, and B dyes of the color filter 307 . It may be implemented by being transmitted in a direction perpendicular to the axis.

The present invention can be applied to various fields. For example, it is possible to implement a mirror mode, a color mode, and an off mode without adding a separate backlight unit or display device by combining it with a separate display panel on the rear (rear) side of a mobile device or tablet device. In the case of the off mode, it is assumed that the display is displayed in a specific color according to an embodiment. Hereinafter, an example in which the present invention is applied to the rear surface of the mobile device will be seen in FIGS. 12 to 14 , and FIG. 15 shows a structure in which a separate display panel is included in the front surface of the mobile device.

The display device of the present invention has a configuration in which two or more display panels are combined, and the first display panel is a display panel that provides a general image and may be variously combined, such as LCD and OLED. Meanwhile, the second display panel may be disposed at a position different from that of the first display panel. In an embodiment, the second display panel may be disposed on the rear surface of the display device, but the present invention is not limited thereto. The second display panel includes the configuration shown in FIGS. 3 to 11 to implement the color mode and the mirror mode as described above.

In an embodiment, a light-transmitting layer that transmits light, a first substrate on one surface of the light-transmitting layer, on which a thin film transistor for controlling the light-transmitting layer for each sub-pixel is disposed, and a first substrate based on the light transmitting layer It has a structure including a second substrate disposed opposite to the dichroic color filter, a polarizing layer polarizing light incident from the second substrate, and a first reflective layer reflecting the incident light through the polarization layer. In addition, the display device includes a control unit that provides a control signal and an image data signal to the first display panel and the second display panel.

In more detail, it is as follows.

12 is a diagram illustrating a display device operating in an off mode according to an embodiment of the present invention.

As described above, the display device may be disposed on the rear surface of the mobile device 1200 in the front. For the convenience of the mobile device 1200 , a camera unit 1210 and a flash unit 1220 may be disposed. In addition, a sensor 1205 for sensing whether the rear surface of the mobile device 1200 can be seen from the outside, that is, whether a cover is on or not, or whether the rear surface of the mobile device 1200 is covered may be additionally disposed. When the sensor 1205 senses that the rear surface is obscured by an object, the off-mode state may be maintained without performing the mirror mode or the color mode.

In the off mode, external light is displayed in a specific color. For example, the first reflective layer may be configured to have a specific color, or the light transmitting layer may be configured to display only a specific color in the color mode. The display panel 1230a may display a specific color or a color of a specific pattern.

13 is a view showing a display device operating in a mirror mode according to another embodiment of the present invention. It has been described above that the camera unit 1210 and the flash unit 1220 may be disposed for the convenience of the mobile device 1200 . The display panel 1230b operates in a mirror mode to reflect external light. In addition, some sub-pixels of the specific region 1231 are driven in a color mode to display information.

14 is a diagram illustrating a display device operating in a color mode according to another embodiment of the present invention. It has been described above that the camera unit 1210 and the flash unit 1220 may be disposed for the convenience of the mobile device 1200 . A preset image or information requiring a notification in real time is output to the display panel 1230c. The entire screen may be the color of the above-described off mode, but may also be a color preset separately. Even in color mode, some areas can be controlled to be driven in mirror mode.

15 is a view showing a display device according to an embodiment of the present invention. The configuration of the first display panel disposed on the front of the mobile device to which the above-described second display panel of FIGS. 12 to 14 is applied is shown. A first display panel 1290 of the mobile device 1200 , a button 1280 controlling the mobile device 1200 , a speaker 1270 , and the like may be disposed. When the first display panel does not operate, the host unit may control the second display panel to output an image to the second display panel in a color mode.

16 is a diagram illustrating components of a display device according to an embodiment of the present invention. The first display panel 1290 and the second display panel 1230 of the mobile device 1200, and an image provided to these display panels or the operation of the second display panel 1230 in the off mode, mirror mode, and color mode and a host unit 1250 that controls it, for example.

The host unit 1250 provides an image to be output to each of the display panels 1230 and 1290 , and may sense a situation in which the display panels 1230 and 1290 are exposed to the outside.

In a display device in which two types of display panels are combined as shown in FIGS. 12 to 16 , the display panel can be driven according to a usage situation, and thus power of the display panel can be saved. In particular, since the display panel on the back uses less electricity, it has the effect of reducing battery consumption, and the various image and mirror modes on the back provide convenience to check information without the need to operate the display panel on the front of the mobile.

When the present invention is applied, the mirror mode and the color mode can be implemented using external light without coupling a separate backlight unit to the display device. In particular, it is possible to implement a display device disposed on the back side instead of a main display device in a device such as a mobile device, or to a display device that supports both a mirror mode and a color mode outside a building. Also, a display device such as digital paper or electronic ink may output an image using external light. Accordingly, the embodiment of the present invention is not limited to a specific display device or display panel.

When the present invention is applied, a mirror mode and a color mode for outputting an image are performed using the structure shown in FIG. 3 without adding the separate cells 21, 23, and 25 applied to implement the color mode in FIG. configurable. In the color mode, it is possible to implement simple display elements (characters, clocks, etc.) and to change the color of the back side.

In a display device that supports mirror mode, when a reflective film (DBEF core) is laminated on the upper surface of a display device such as an LCD, or a reflective polarization layer is removed after removing the external polarization layer, mirror reflection is always observed. After waking up, glare and discomfort in appearance occurred. However, in the present invention, since it is possible to switch between the mirror mode, the color mode, and the off mode, the above-described problem can be solved.

When the embodiment of the present invention is applied to a device having a main display device, such as a mobile rear, the overall thickness is not increased. In addition, since the second display panel on the rear side is coupled and various information can be output as images in color mode without adding a separate cell, the cost-effectiveness of the product can be increased. Therefore, the slim design and cost-saving effect are great.

In particular, in the prior art, only one color could be expressed for the color mode, but when the present invention is applied, various colors and detailed images can be displayed, so that visibility can be improved. In particular, when disposed on the rear surface of the mobile device, the display color may be matched to the case color of the mobile device.

In addition, since external light is reflected without a backlight, the driving voltage is not increased, so that when applied to the second display device of a mobile device, the lifespan of the battery can be increased.

On the other hand, when the present invention is applied, color can be implemented even outdoors, so that visibility can be improved. In particular, although a separate polarization layer 19 is also included on the upper surface in FIG. 2 , in the present invention, since a single polarization layer 320 is included, it is possible to maximize the mirror effect by increasing the reflectance.

17 is a display device according to another embodiment of the present invention.

The above-described display panel or display device does not include a backlight unit. 17 shows that a backlight unit is coupled to a display panel supporting a mirror mode installed on an exterior wall of a building to increase visibility even at night. The overall configuration is the same as described in FIG. 3 . That is, in addition to the components of FIG. 3 , the backlight units 1710a and 1710b are combined. In the case of a large display panel installed on the exterior wall of a building, a backlight unit can be added to output an image even at night. However, in this case, the controller 1750 may set whether to display an image using the backlight unit.

A reflective layer 310 and a polarizing layer 320 are disposed on a first surface, a first substrate 301 on which a thin film transistor 305 for controlling a liquid crystal layer for each sub-pixel is disposed on a second surface, light such as a liquid crystal layer The transmission layer 306 and the second substrate 309 facing the first substrate 301 based on this, and on which the dichroic color filter 307 is disposed on the first surface, are constituted, and the second substrate 309 is provided. and a control unit 1750 for controlling the thin film transistor to change the reflectance of light incident through the .

Here, the thin film transistor controls the color mode by matching the optical axis of the polarized light transmitted through the light transmitting layer 306 such as the liquid crystal layer and the absorption axis of the dichroic color filter 307 or the light transmitting layer 306 such as the liquid crystal layer. ), the optical axis of the polarized light passing through and the absorption axis of the dichroic color filter 307 are perpendicular to each other to control the mirror mode.

In addition, according to an embodiment of the present invention, the backlight units 1710a and 1710b are disposed on the first substrate 301 so that an image can be output in a color mode at night even in a state in which external light is weak. The controller 1750 may control the on/off of the backlight units 1710a and 1710b to implement a color mode at night or in a situation in which external light is weak.

17 , a display device capable of driving both the mirror mode and the color mode is mounted on the exterior wall of the building to enhance the aesthetics of the building. In addition, an area in which information is not provided while being able to provide information may be operated in a mirror mode.

In the above, although the embodiment of the present invention has been mainly described, various changes or modifications may be made at the level of those skilled in the art. Accordingly, it will be understood that such changes and modifications are included within the scope of the present invention without departing from the scope of the present invention.

301: first substrate 305: thin film transistor
306: light transmitting layer 307: dichroic color filter
310: first reflective layer 320: polarizing layer
330: second reflective layer 1200: mobile device

Claims (17)

a light-transmitting layer that transmits light;
a first substrate disposed on one surface of the light transmitting layer and having a thin film transistor configured to control the light transmitting layer for each sub-pixel;
a second substrate facing the first substrate with respect to the light-transmitting layer and on which a dichroic color filter is disposed;
a polarization layer polarizing the light incident on the second substrate; and
and a first reflective layer that reflects the incident light through the polarization layer,
The dichroic color filter includes a reactive mesogen (RM) and a dichroic dye aligned in one direction by the RM,
The first reflective layer, the polarizing layer, the first substrate, the light transmitting layer, the dichroic color filter, and the second substrate are disposed in this order.
delete The method of claim 1,
The light transmitting layer is a liquid crystal layer,
The thin film transistor controls a color mode by matching an optical axis of the polarized light transmitted through the light transmitting layer and an absorption axis of the dichroic color filter.
According to claim 1,
The light transmitting layer is a liquid crystal layer,
and the thin film transistor controls a mirror mode by making an optical axis of the polarized light transmitted through the light transmitting layer perpendicular to an absorption axis of the dichroic color filter.
According to claim 1,
The color filter includes R (red), G (green), B (blue) and W (white),
A display panel in which a second reflective layer is disposed on the second substrate to correspond to the W subpixels on which the W color filters are disposed.
According to claim 1,
The color filter includes R (red), G (green), B (blue), and Black (black).
According to claim 1,
The color filter includes R (red), G (green) and B (blue),
A space is disposed between the R, G, and B;
A display panel in which a second reflective layer is disposed to correspond to a portion of the space.
delete According to claim 1,
and the polarization layer is disposed between the first substrate and the thin film transistor.
a first display panel providing an image;
A light-transmitting layer for transmitting light, a first substrate disposed on one surface of the light-transmitting layer, a thin film transistor for controlling the light transmitting layer for each sub-pixel is disposed on the first substrate based on the light transmitting layer a second substrate disposed opposite to each other and having a dichroic color filter disposed thereon; a polarization layer polarizing light incident from the second substrate; and a first reflective layer reflecting light incident through the polarization layer; display panel; and
a host unit for providing a control signal and an image data signal to the first display panel and the second display panel;
The dichroic color filter includes a reactive mesogen (RM) and a dichroic dye aligned in one direction by the RM,
The first reflective layer, the polarizing layer, the first substrate, the light transmitting layer, the dichroic color filter, and the second substrate are arranged in this order,
The first display panel and the second display panel output images in different directions.
11. The method of claim 10,
The light transmitting layer of the second display panel is a liquid crystal layer,
The thin film transistor controls a color mode by matching an optical axis of the polarized light passing through the light transmitting layer and an absorption axis of the dichroic color filter.
11. The method of claim 10,
The light transmitting layer of the second display panel is a liquid crystal layer,
The thin film transistor controls a mirror mode by making an optical axis of the polarized light transmitted through the light transmitting layer perpendicular to an absorption axis of the dichroic color filter.
11. The method of claim 10,
The color filter includes R (red), G (green), B (blue) and W (white),
A second reflective layer is disposed on the second substrate to correspond to the W subpixel on which the W color filter is disposed.
11. The method of claim 10,
The color filter includes R (red), G (green) and B (blue),
A space is disposed between the R, G, and B;
A display device in which a second reflective layer is disposed to correspond to a part of the space.
a first substrate on which a reflective layer and a polarizing layer are disposed on a first surface, and a thin film transistor for controlling a liquid crystal layer for each sub-pixel is disposed on a second surface;
liquid crystal layer;
a second substrate facing the first substrate with respect to the liquid crystal layer and having a dichroic color filter disposed on a first surface thereof; and
A control unit for changing the reflectance of light incident through the second substrate by controlling the thin film transistor,
The dichroic color filter includes a reactive mesogen (RM) and a dichroic dye aligned in one direction by the RM,
The reflective layer, the polarizing layer, the first substrate, the liquid crystal layer, the dichroic color filter, and the second substrate are arranged in this order.
16. The method of claim 15,
The thin film transistor controls the color mode by matching the optical axis of the polarized light passing through the liquid crystal layer and the absorption axis of the dichroic color filter, or the optical axis of the polarized light passing through the liquid crystal layer and absorption of the dichroic color filter A display device that controls the mirror mode by making the axis vertical.
16. The method of claim 15,
A backlight unit is disposed on the first substrate,
The control unit controls on/off of the backlight unit.

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