KR100764996B1 - Display apparatus and portable communication terminal using its - Google Patents

Abstract

A display device and a mobile communication terminal using the same are provided to maximize efficiency of light use by maximally using light emitted from a light guide plate of the backlight device. A backlight device(110) generates light and emits the generated light in both directions. A main liquid crystal panel(120) is placed at one side of the backlight device, and displays a main image. A sub-liquid crystal panel(130) is placed at the other side of the backlight device, and displays a sub-image. A reflective polarizer is placed between the backlight device and at least one of the liquid crystal panels. The reflective polarizer includes a first reflective polarizer(141) placed between the backlight device and the main liquid crystal panel, and a second reflective polarizer(142) placed between the backlight device and the sub-liquid crystal panel.

Description

Display apparatus and mobile communication terminal using the same

1 is a view showing a conventional liquid crystal display device.

2 is a diagram illustrating a liquid crystal display according to an exemplary embodiment of the present invention.

3 is a diagram illustrating a display mode of a main screen in FIG. 2;

4 is a diagram illustrating a display mode of a sub screen in FIG. 2;

5 is a diagram illustrating a modified example of the liquid crystal display according to the exemplary embodiment of the present invention.

6 is a view illustrating another modified example of the liquid crystal display according to the exemplary embodiment of the present invention.

7 illustrates a terminal to which a liquid crystal display device according to the present invention is applied.

<Explanation of symbols for main parts of the drawings>

100: liquid crystal display device 110: backlight device

111 light emitting unit 112 light guide plate

120: main liquid crystal panel 130: sub liquid crystal panel

141,142: reflective polarizer

The present invention relates to a display device and a mobile communication terminal using the same.

In recent years, the liquid crystal display of the flat panel display has been increasingly used as an alternative means of overcoming the disadvantages of cathode ray tube (CRT) due to the advantages of miniaturization, light weight, low power consumption, and full color. It is expanding.

In general, the liquid crystal display may be classified into two types: a transmissive liquid crystal display using a backlight as a light source and a reflective liquid crystal display using external light without using the backlight as a light source. The liquid crystal display uses a backlight as a light source to realize a bright image even in a dark external environment, but has a problem in that power consumption by the backlight is large. On the other hand, the reflection type liquid crystal display device consumes less power because it uses external light, but it is difficult to use when the external light is dark.

As an alternative to overcome this limitation, many transflective liquid crystal displays have been employed. Since the transflective liquid crystal display has both a reflecting portion and a transmitting portion at the same time in a unit pixel, it may be selected and used as a reflective type or a transmissive type as necessary.

In addition, the mobile terminal to which the transflective liquid crystal display device is applied has a main display unit on one side of the case to display transmission and reception information, and an auxiliary display unit is installed on the opposite side of the case.

The conventional double-sided display device will be described with reference to FIG. 1 as follows.

The double-sided display type liquid crystal display device 302 is composed of a main display unit 303 having a main screen 301e and a sub display unit 304 having a sub screen 301h. The main display unit 303 includes a transflective reflective liquid crystal display panel (hereinafter referred to as a main display panel) 303a and a main backlight 303b for illuminating the main display panel 303a. 303b is composed of a light source 303c and a light guide plate 303d.

The sub display unit 304 is a semi-transmissive reflective liquid crystal display panel (hereinafter referred to as a sub display panel) 304a which is smaller than the main display panel 303a, and a sub backlight for illuminating the sub display panel 304a. It consists of 304b, and the sub backlight 304b is comprised from the light source 304c and the light guide plate 304d.

The main backlight 303b and the sub backlight 304b are composed of parts of substantially the same type (light sources 303c and 304c and light guide plates 303d and 304d) except that the sizes are different.

However, in the conventional mobile terminal, since the main backlight 303b and the sub backlight 304b are provided, respectively, the number of parts is increased, the internal structure is complicated, and the product thickness is thick.

In addition, the size of the sub screen is smaller than that of the main screen, and information that can be displayed on such a sub screen is limited.

The present invention provides a double-sided display device and a mobile communication terminal using the same.

The present invention provides a display device capable of selectively displaying a main screen and a sub screen using one backlight device, and a mobile communication terminal using the same.

The present invention provides a display device and a mobile communication terminal using the same, by placing a reflective polarizer between two liquid crystal panels and a central light guide plate so that a maximum amount of light can be irradiated to a main or sub screen.

In accordance with another aspect of the present invention, a display device includes: a backlight device for generating light and emitting the generated light in both directions; A main liquid crystal panel positioned on the other side of the backlight device and configured to display a main screen; A sub liquid crystal panel positioned on one side of the backlight device and configured to display a sub screen; And a reflective polarizer positioned between the backlight device and the at least one liquid crystal panel.

Hereinafter, a liquid crystal display according to an exemplary embodiment of the present invention will be described with reference to the accompanying drawings.

2 is a diagram for describing a liquid crystal display according to an exemplary embodiment of the present invention.

Referring to FIG. 2, the liquid crystal display 100 includes a backlight device 110, a main liquid crystal panel 120, a sub liquid crystal panel 130, and first and second reflective polarizers 141 and 142.

The backlight device 110 is installed at the center of the liquid crystal display 100 to generate light P and emit the generated light in both directions. To this end, the backlight device 110 includes a light emitting unit 111 and a light guide plate 112, and the light emitting unit 111 irradiates light to one end of the light guide plate 112, for example, an LED (Light Emitting). Diodes or rod-shaped cathode tubes (for example, Cold Cathode Fluorescence Tube (CCFT), Hot Cathode Fluorescence Tube (HCFT)).

The light guide plate 112 is a surface of the light emitted from the light emitting unit 111 is introduced into the inside, and the surface light emitted to the one side 113 and the other side 114, a transparent acrylic resin or polycarbonate resin or It may consist of transparent resin materials, such as an epoxy resin, or glass.

Herein, the light guide plate 112 may emit light at a ratio of 1: 1 or different from each other by the light emitted from the surface 113 and the other surface 114. That is, the amount of light irradiated onto the main screen Wm and the sub screen Ws may be the same or different.

The main liquid crystal panel 120 is filled with a liquid crystal layer (not shown) between two substrates 123 and 125, and includes first and second polarizing plates 121 and 127 attached to rear surfaces of the substrates 123 and 125. That is, the main liquid crystal panel 120 includes a TFT array substrate 123, a liquid crystal layer, and a color film array substrate 125 in the case of a TFT, and the first polarizing plate 121 is formed on the rear surface of the TFT array substrate 123. The second polarizer 127 may be attached to the front surface of the color film array substrate 125.

The liquid crystal layer is configured to have a 90 ° angle on two transparent electrodes oriented so that the axis of the liquid crystal molecules in the longitudinal direction is parallel to the electrode plane, and when a nematic liquid crystal is injected therefrom, Towards the other electrode, the molecular length axis of the liquid crystal is continuously arranged 90 ° twist. Here, the liquid crystal is described as a TN (Twist Nematic) mode by way of example, it may form a liquid crystal panel to which the ECB, OCB, IPS or VA mode is applied.

The first and second polarizing plates 121 and 127 are composed of a plurality of layers, and the support TAC (tri-acetyl-cellulose) is used on both sides of the polarizing material mainly on a polymer polarizing material that polarizes incident light. An adhesive layer may be present to adhere the polarizing plates 121 and 127 to the glass surface.

In addition, the sub liquid crystal panel 130 includes two substrates 133 and 135 and a liquid crystal layer (not shown), and third and fourth polarizing plates 131 and 137 attached to both surfaces of the two substrates 133 and 135. Detailed description thereof will be omitted.

Here, the main and sub liquid crystal panels 120 and 130 are transmissive liquid crystal panels, and the transmission axes of the first polarizing plate 121 and the second polarizing plate 127 are formed perpendicular to each other, and the third polarizing plate 131 and the fourth polarizing plate 137. ) Is also perpendicular to each other.

The present invention may include one or more reflective polarizers in the liquid crystal display 100, and the reflective polarizers may be configured between the backlight device 110 and the main liquid crystal panel 120 or the sub liquid crystal panel 130. Can be.

When the two reflective polarizers 141 and 142 are provided as shown in FIG. 2, the first reflective polarizer 141 is positioned between the backlight device 110 and the main liquid crystal panel 120, and the second reflective polarizer 142 is formed of the back. The light device 110 is positioned between the sub liquid crystal panel 130.

Here, the reflective polarizers 141 and 142 may be configured as wire lattice polarizers, and the wire lattice polarizers are metal wires grating at regular intervals to selectively transmit or reflect electromagnetic waves according to polarization, and various substrates. It may have a metal wire structure of various materials and metals. In addition, the grating cross section may have various structures such as a rectangle, a triangle, and a semicircle.

When the period of the metal wire array is shorter than the half wavelength of the incident electromagnetic waves, the reflective polarizers 141 and 142 reflect the polarization component (s wave or p wave) parallel to the metal wire and are perpendicular to the polarization component (p wave or s wave). ) Is transmitted. Using this phenomenon, a planar polarizer having excellent polarization efficiency, high transmittance, and a wide viewing angle can be manufactured. Such a device is called a reflective polarizer.

Accordingly, when the polarization axis (that is, the transmission axis) of the first reflection polarizer 141 and the second reflection polarizer 142 is disposed so as to be perpendicular to each other (⊙, ↔), the p-wave is transmitted through the first reflection polarizer 141. And the s wave is reflected, and in the second reflecting polarizer 142, the s wave is transmitted and the p wave is reflected.

The light P2 transmitted by the first reflective polarizer 141 and the light P2 reflected by the second reflective polarizer 142 are irradiated onto the main liquid crystal panel 120, thereby providing a main screen to the observer 151. can do. In addition, the light P1 transmitted by the second reflective polarizer 142 and the light P1 reflected by the first reflective polarizer 141 are irradiated onto the sub liquid crystal panel 130 to provide a sub-screen to the observer 152. can do. That is, the present invention allows the light generated by the backlight device to be irradiated to the sub screen Ws or the main screen Wm.

Here, the display mode of the main liquid crystal panel 120 and the sub liquid crystal panel 130 may control the display operation of each screen or control the display of both screens through power control.

In addition, since the light emitted from the backlight device is utilized almost 100%, the number of light emitting units (eg, LEDs) does not have to be increased.

In addition, the transmission axis of the first reflective polarizer 141 is formed in the same direction as the transmission axis of the first polarizing plate 121 of the main liquid crystal panel 120, and the transmission axis of the second reflective polarizer 142 is the sub liquid crystal panel 130. Is formed in the same direction as the transmission axis of the third polarizing plate 131. For example, the transmission axes of the first or second reflective polarizers 141 and 142 are formed in the same direction as the grating direction of the metal wires of the first or third polarizing plates 121 and 131 attached to the lower portion of the liquid crystal panel.

3 is a diagram illustrating a display mode of a main screen in a liquid crystal display according to an exemplary embodiment of the present invention.

Referring to FIG. 3, the light P generated by the light emitting unit 111 of the backlight device 110 is irradiated to the light guide plate 112, and the light irradiated to the light guide plate 112 is provided on one surface 113 and the other surface. It is emitted to 114.

The first reflection polarizer 141 transmits the p-wave P2 and reflects the s-wave P1 among the light emitted from one surface 113 of the light guide plate 112. The second reflection polarizer 142 transmits the s-wave P1 and reflects the s-wave P2 among the light emitted from the other surface 114 of the light guide plate 112, and is reflected by the second reflection polarizer 142. Light passes through the first light polarizer 141 through the light guide plate of the backlight device.

The light P2 of the p-wave component transmitted through the first reflective polarizer 141 passes through the main liquid crystal panel 120 to display the main screen Wm. That is, the first polarizing plate 121, the first substrate 123, the liquid crystal layer, the second substrate 125, and the second polarizing plate 127 of the main liquid crystal panel 120 pass through the viewer 151 to the main screen. (Wm) is displayed.

4 is a diagram illustrating a display mode of a sub screen in a liquid crystal display according to an exemplary embodiment of the present invention.

Referring to FIG. 4, the light generated from the light emitting unit 111 of the backlight device 110 is irradiated to the light guide plate 112, and the light irradiated to the light guide plate 112 is provided on one side 113 and the other side 114. The second reflection polarizer 142 transmits the s-wave P1 and the p-wave P2 is reflected among the light emitted to the other surface 114 of the light guide plate 112. In addition, the light P1 of the s-wave component reflected by the first reflective polarizer 141 passes through the light guide plate 112 of the backlight device 110 and passes through the second reflective polarizer 142.

The light P1 of the s-wave component transmitted through the second reflective polarizer 142 passes through the sub liquid crystal panel 130 to display the sub screen Ws. That is, the light of the s-wave component passes through the third polarizing plate 131, the first substrate 133, the liquid crystal layer, the second substrate 135, and the fourth polarizing plate 137 of the sub liquid crystal panel 130, and observes the viewer. The sub screen Ws is displayed to 152.

5 is a diagram illustrating a modified example of the liquid crystal display according to the exemplary embodiment of the present invention.

FIG. 5 is a configuration in which the reflective polarizer of one of the two reflective polarizers is removed from the component of FIG. 2. For example, only the second reflective polarizer 142 is formed between the backlight device 110 and the sub liquid crystal panel 130, and the light irradiated onto the main screen Wm is transferred from the light guide plate 112 to the main liquid crystal panel 120. The light emitted and the light reflected by the second reflective polarizer 142 are used, and the light irradiated onto the sub-screen Ws uses only the light transmitted from the second reflective polarizer 142.

In addition, when the first reflection polarizer 141 is removed in the configuration as shown in FIG. 2, only the light component irradiated to the sub-screen by the first reflection polarizer 141 is reduced, and the second reflection polarizer 142 may be removed. In this case, only the light component irradiated to the main screen by the second reflective polarizer 142 is reduced.

6 is a diagram illustrating another modified example of the liquid crystal display according to the exemplary embodiment of the present invention.

6 may remove the first polarizing plate 121 of the main liquid crystal panel 120 and / or the third polarizing plate 131 of the sub liquid crystal panel 130 from the components of FIG. 2. Since the transmission axis of the first polarizing plate 121 of the main liquid crystal panel 120 is formed in the same direction as the first reflective polarizer 141, the first polarizing plate 121 may be removed.

Similarly, the third polarizing plate 131 of the sub liquid crystal panel 130 may also be removed from the sub liquid crystal panel 130 side. Even if the third polarizer 131 is removed, the second polarizer 142 may function as the third polarizer 131.

In this way, even if the first polarizing plate 121 or / and the third polarizing plate 131 is removed from the liquid crystal panel side, the amount of light irradiated onto the screen is not reduced and the image quality is not deteriorated.

 7 is a perspective view of a foldable terminal to which a liquid crystal display according to an exemplary embodiment of the present invention is applied.

As shown in FIG. 7A, when the upper main body 201 of the terminal 200 is closed, only light having an s-wave component is emitted from the backlight device to the sub liquid crystal panel to display the sub screen Ws. . The sub liquid crystal panel may be used to perform time, date, message confirmation, and multimedia functions (game, Internet search, etc.).

When the upper main body of the terminal is opened as shown in (b) of FIG. 7, the light P2 of the p-wave component is emitted from the backlight device to the main liquid crystal panel to display information on the main screen Wm. In addition, among the light emitted from the backlight device, the light P1 having the s-wave component may be irradiated to the sub liquid crystal panel to display information on the sub screen Ws. The display of the sub screen at this time may be provided as a user option.

The present invention can improve the utilization of the sub screen by providing the same size of the main and sub screens by using one backlight device and two liquid crystal panels.

Although the present invention has been described above with reference to the embodiments, these are only examples and are not intended to limit the present invention, and those skilled in the art to which the present invention pertains may have an abnormality within the scope not departing from the essential characteristics of the present invention. It will be appreciated that various modifications and applications are not illustrated.

For example, each component shown in detail in the embodiment of the present invention may be modified. And differences relating to such modifications and applications will have to be construed as being included in the scope of the invention defined in the appended claims.

According to the display device according to the present invention, by maximizing the light emitted from the light guide plate of the backlight device, the light utilization efficiency can be maximized.

In addition, the two liquid crystal panels configured on both sides of the light guide plate can be configured in almost the same size, and the amount of light irradiated to the main and sub screens can be made substantially the same.

In addition, by using a single light guide plate to direct the light to both sides, it is not necessary to add the number of light emitting units, for example, LEDs.

By using two panels, one or both of the main and sub screens can be used simultaneously.

Claims (14)

A backlight device for generating light and emitting the generated light in both directions; A main liquid crystal panel positioned at one side of the backlight device for displaying a main screen; A sub liquid crystal panel positioned on the other side of the backlight device and configured to display a sub screen; And a reflective polarizer positioned between the backlight device and at least one liquid crystal panel. The method of claim 1, The reflective polarizer includes a first reflective polarizer positioned between the backlight device and the main liquid crystal panel, and a second reflective polarizer positioned between the backlight device and the sub liquid crystal panel. The method of claim 2, And the first and second reflective polarizers are formed in directions in which transmission axes are perpendicular to each other. The method of claim 2, The main liquid crystal panel includes a liquid crystal layer filled between the first and second substrates, a first polarizing plate positioned on the rear surface of the first substrate and having the same transmission axis as the first reflective polarizer, and a front portion of the second substrate. Display device including a second polarizing plate positioned in the. The method of claim 2, The sub liquid crystal panel includes a liquid crystal layer filled between the third and fourth substrates, a third polarizing plate positioned on the rear side of the third substrate and having the same transmission axis as the second reflective polarizer, and a front portion of the fourth substrate. And a fourth polarizing plate attached to the display device. The method according to any one of claims 1 to 3, The reflective polarizer transmits light having the same component as the transmission axis of the reflective polarizer among the light emitted from the backlight device, and reflects other light. The method of claim 2, The main liquid crystal panel displays the main screen by receiving the light transmitted through the first reflective polarizer and the light reflected by the second reflective polarizer. The method of claim 2, The sub liquid crystal panel is configured to display a sub screen by receiving the light transmitted through the second reflective polarizer and the light reflected by the first reflective polarizer. The method of claim 5, The backlight device includes a light emitting part for generating light, and a light guide plate that receives the generated light and emits the light in both directions. The method of claim 9, The light emitting unit includes a CCFL or a light emitting diode. The method of claim 1, The reflective polarizer is positioned between the backlight device or the liquid crystal panel. The method of claim 2, The main liquid crystal panel is a display device in which a liquid crystal layer is filled between the first and second substrates, the first reflective polarizer is located on the rear surface of the first substrate, the polarizing plate is located on the front surface of the second substrate. The method of claim 2, The sub liquid crystal panel is a display device in which a liquid crystal layer is filled between the first and second substrates, the second reflective polarizer is positioned on the rear surface of the first substrate, the polarizer is located on the front surface of the second substrate. A mobile terminal comprising the display device of claim 1.

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