KR101774577B1 - Liquid Crystal Display And Driving Method For The Same - Google Patents

Abstract

A liquid crystal display according to an embodiment of the present invention includes a light guide plate, a light source provided on at least one side of the light guide plate, a first optical member positioned on one side of the light guide plate, a first liquid crystal panel positioned on the first optical member, A second liquid crystal panel positioned on the second optical member, a light control member positioned on the light guide plate for transmitting or reflecting light, and a motor for driving the light control member .

Description

[0001] The present invention relates to a liquid crystal display device,

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a liquid crystal display device and a driving method thereof, and more particularly, to a liquid crystal display device capable of realizing a liquid crystal display device in both-side or single-sided mode and a driving method thereof.

2. Description of the Related Art [0002] Recently, various portable electronic devices such as mobile phones, PDAs, and notebooks have been developed, and thus a demand for a lightweight thin flat panel display device is increasing. As such flat panel display devices, a liquid crystal display (LCD), a plasma display panel (PDP) and an organic light emitting diode (OLED) have been actively studied. A liquid crystal display device in which the ease of driving means and the realization of a high image quality are easily spotlighted.

A liquid crystal display device classified as a light-receiving-type display device may include a backlight unit disposed below the liquid crystal panel for providing light to the liquid crystal panel, in addition to a liquid crystal panel for displaying an image.

In recent years, a double-side liquid crystal display device that implements images on both sides in addition to a cross-sectional liquid crystal display device that implements light in only one direction has been developed. In the double-sided type liquid crystal display device, liquid crystal panels are positioned on both sides of a light guide plate guiding light provided from a light source, thereby realizing images on both sides.

1 is a view showing a conventional double-side liquid crystal display device.

Referring to FIG. 1, a conventional double-side liquid crystal display 10 includes a first light source 10a for providing light to a lower portion and a second light source 10b for providing light to an upper portion. The upper diffuser plate 12a and the lower diffuser plate 12b are positioned with the first light source 10a and the second light source 10b interposed therebetween. Then, the upper diffusion plate 12a and the lower diffusion plate 12b are fixed by the bracket 13.

The upper optical member 14a is located on the upper diffuser plate 12a and the lower optical member 14b is located on the lower diffuser plate 12b. The upper optical member 14a and the lower optical member 14b are made of a diffusion sheet, a prism sheet or the like. Thus, a backlight unit including the light sources 10a and 10b, the diffusion plates 12a and 12b, and the optical members 14a and 14b is constructed.

The upper liquid crystal panel 16 on which the color filter substrate 15a and the TFT substrate 15b are attached is positioned on the upper optical member 14a and the color filter substrate 17a and the TFT substrate 15b are also disposed on the lower optical member 14b. The lower liquid crystal panel 18 to which the liquid crystal panel 17b is adhered is positioned.

In the conventional double-side liquid crystal display device having the above-described structure, since a single backlight unit needs to realize an image on both sides, a light quantity of about 200% of the conventional liquid crystal display device should be emitted. Even when an image is formed only on a cross section of a double-side liquid crystal display device, the backlight unit needs to emit a light amount of 200%. This is because the amount of light is absorbed by the liquid crystal or the like on the surface which does not implement an image.

Accordingly, the conventional double-side liquid crystal display device has a problem in that power consumption is increased to emit light of 200% even when only a single section is implemented.

Therefore, the present invention provides a liquid crystal display device and a driving method thereof that can prevent an increase in power consumption of a backlight unit when an image is formed on a non-both-side surface.

According to an aspect of the present invention, there is provided a liquid crystal display device including a light guide plate, a light source provided on at least one side of the light guide plate, a first optical member disposed on one side of the light guide plate, A second optical member positioned on the other side of the light guide plate, a second liquid crystal panel positioned on the second optical member, a light control member positioned on the light guide plate and transmitting or reflecting light, And a motor portion for driving the member.

The light control member may be positioned between the light guide plate and the first optical member or between the light guide plate and the second optical member.

The light control member may include a transparent portion and a reflective portion.

The transparent portion may be a region where the transparent film is located, and the reflective portion may be a region where the reflective layer is located on the transparent film.

The light control member may be divided into a transparent portion on one side and a reflective portion on the other side.

The motor unit may be positioned on both sides of the light guide plate and facing each other.

The light control member may be connected to the motor unit and may be driven laterally by the motor unit.

A method of driving a liquid crystal display according to an exemplary embodiment of the present invention may include determining whether the liquid crystal display device is in a two-sided mode or not, driving a motor provided on both sides of a light guide plate, aligning a transmissive portion or a reflective portion of the light control member Supplying a current corresponding to the double-side or single-sided mode to the light source to provide light, and implementing the image through at least one of the first liquid crystal panel and the second liquid crystal panel through the light.

When the liquid crystal display device is determined to be in the two-sided mode, the motor section is driven to align the transmissive portion of the light control member, and light is provided from the light source to implement an image in the first liquid crystal panel and the second liquid crystal panel .

When the liquid crystal display device is determined not to be in the double-sided mode, the motor unit is driven to align the reflection unit of the light control member, and supplies a current corresponding to the single-sided mode to the light source, Or the second liquid crystal panel.

The liquid crystal display device and the driving method thereof according to the present invention have an advantage that the power consumption of the backlight unit can be prevented from increasing when an image is formed on a cross section.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view showing a conventional two-sided liquid crystal display;
2 is an exploded perspective view illustrating a liquid crystal display device according to an embodiment of the present invention.
3 is a cross-sectional view taken along line I-I 'of FIG. 2;
4 shows a light control member according to an embodiment of the invention.
5 and 6 are diagrams illustrating the operation of the light control member and the motor unit according to an embodiment of the present invention.
7 is a flowchart illustrating a method of driving a liquid crystal display according to an embodiment of the present invention.
8 is a flowchart illustrating a method of driving a liquid crystal display according to an exemplary embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

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

2, the liquid crystal display 100 according to an exemplary embodiment of the present invention includes a light guide plate 120, light sources 130a and 130b provided on at least one side of the light guide plate 120, A first optical member 140 positioned on the first optical member 140, and a first liquid crystal panel 160 positioned on the first optical member 140. The second optical member 150 positioned on the other side of the light guide plate 120 and the second liquid crystal panel 170 positioned on the second optical member 150 are disposed on the light guide plate 120, (195a, 195b) for driving the light control member (190) and the light control member (190).

More specifically, the upper cover 110a and the lower cover 110b serve as a case of the liquid crystal display device 100, and the light guide plate 120, the light source 130, the first and second optical members 140 and 150 The first and second liquid crystal panels 160, the light control member 190, and the motor units 195a and 195b.

The upper cover 110a and the lower cover 110b are formed in a rectangular frame shape so that they can be coupled to each other.

The light guide plate 120 guides light incident from the light sources 130a and 130b and converts the light source into a surface light source. The light guide plate 120 is made of PMMA (PolyMethylMethAcrylate) or the like having excellent reflectance. The light guide plate 120 provides the light of the light source to the upper portion or the lower portion.

The light sources 130a and 130b may be formed on at least one side of the light guide plate 120 along the major axis direction of the light guide plate 120 or may be formed on at least one side of each side of the light guide plate 120 .

Here, the light emitted from the light sources 130a and 130b may be incident directly into the light guide plate 120. [ The light sources 130a and 130b may be LED assemblies and the LED assemblies may be a plurality of LED light sources 132 arranged on the LED PCB 131. [ A reflection plate (not shown) is positioned on the LED PCB 131 to reflect light emitted from the LED light source 132.

For example, the light sources 130a and 130b may be a cold cathode fluorescent lamp (CCFL), a hot cathode fluorescent lamp (CCFL) Lamp: HCFL, and an external electrode fluorescent lamp (EEFL). However, the present invention is not limited thereto.

The first optical member 140 and the second optical member 150 positioned on one side and the other side of the light guide plate 120 serve to diffuse or condense the light emitted from the light guide plate 120.

The first optical member 140 and the second optical member 150 are composed of diffusion sheets 141 and 151 and light collecting sheets 142 and 152, respectively. The diffusion sheets 141 and 151 serve to diffuse the light incident from the light guide plate 120 and to uniform the brightness of light. The light collecting sheets 142 and 152 may be at least a prism sheet, a microlens sheet, a lenticular lens sheet, or the like, and collect light to improve brightness.

Thus, the backlight unit 200 including the light guide plate 120, the light sources 130a and 130b, and the first and second optical members 140 and 150 is formed.

The first liquid crystal panel 160 and the second liquid crystal panel 170 which are respectively disposed on the first optical member 140 and the second optical member 150 are parts where an image is implemented, And first and second substrates 161 and 171 and a second substrate 162 and 172, which are opposite to each other.

Although not shown in the drawings, a plurality of pixels may be defined by intersecting a plurality of scan lines and data lines in a matrix form on a first substrate 161 or 171 called a TFT array substrate. Each pixel is provided with a thin film transistor (TFT) capable of turning on / off a signal, and a pixel electrode connected to the thin film transistor may be positioned.

The second substrates 162 and 172, which are called color filter substrates, are provided with color filters of red (R), green (G), and blue (B) respectively corresponding to a plurality of pixels, And a black matrix for covering non-display elements such as thin film transistors. Further, a transparent common electrode covering them may be provided.

The printed circuit boards 163 and 173 are connected to at least one side of the liquid crystal panel 160 via connecting members 164 and 174 such as a flexible circuit board or a tape carrier package The upper panel guide 180a and the lower panel guide 180b, respectively.

The first liquid crystal panel 160 and the second liquid crystal panel 170 having the structures described above are turned on when the selected thin film transistor is turned on for each scan line by on / off signals of the gate driving circuit transferred from the scan lines The data voltage of the data driving circuit is transmitted to the corresponding pixel electrode through the data line and accordingly the alignment direction of the liquid crystal molecules is changed by the electric field between the pixel electrode and the common electrode,

The upper panel guide 180a and the lower panel guide 180b that surround the edges of the first liquid crystal panel 160 and the second liquid crystal panel 170 may be formed by the first liquid crystal panel 160 and the second liquid crystal panel 170, And each of them plays a supporting role.

Accordingly, the liquid crystal display device 100 of the present invention can be configured by housing the backlight unit 200, the first liquid crystal panel 160, and the second liquid crystal panel 170.

The liquid crystal display 100 of the present invention further includes a light control member 190 and motor units 195a and 195b on one side of the light guide plate 120. [

FIG. 3 is a cross-sectional view taken along line I-I 'of FIG. 2, and FIG. 4 is a view illustrating a light control member according to an embodiment of the present invention.

3, the motor units 195a and 195b are disposed on both sides of the light guide plate 120, the first optical member 140 is positioned on one side of the light guide plate 120, The first liquid crystal panel 160 is positioned. The second optical member 150 is positioned on the other side of the light guide plate 120 and the second liquid crystal panel 170 is positioned on the second optical member 150.

In the light guide plate 120, the light guide plate patterns 121 of negative or positive angle are located on the surface from which light is emitted. The light guide plate patterns 121 serve to facilitate the output of the totally reflected light in the light guide plate 120.

The light guide plate patterns 121 are formed in various shapes such as a circular shape and a square shape for outputting light, and the size can be varied according to the distance from the light source. For example, as the distance between the light guide plate patterns 121 and the light source increases, the distance between the light guide plate patterns 121 may be densely distributed. However, the light guide plate patterns 121 are not limited thereto, and may be formed with a known gap, size, and the like.

Meanwhile, in one embodiment of the present invention, the motor units 195a and 195b are disposed on both sides of the light guide plate 120, respectively. Each of the motor units 195a and 195b has a roller shape provided with a motor and serves to transfer the light control member 190 from side to side.

One end of the light control member 190 is fixed to at least one of the motor units 195a and 195b and the other end thereof is fixed to the other end of the light control member 190 so that the light control member 190 is transferred laterally as the motor units 195a and 195b are driven.

The light control member 190 is positioned between the light guide plate 120 and the second optical member 150. Alternatively, the light control member 190 may be positioned between the light guide plate 120 and the first optical member 140, and may be specifically limited to the first liquid crystal panel 160 or the second liquid crystal panel 170 It does not.

Referring more particularly to Fig. 4, the light control member 190 serves to reflect or transmit light. To this end, the light control member 190 may include a reflective portion A and a transmissive portion B. [

Here, the light control member 190 is composed of a transparent film 191 and a reflective layer 192 formed on the transparent film 191. The transparent film 191 transmits light and may be formed of a transparent film such as PET (Poly Ethylene Terephthalate), PC (Poly Carbonate), PE (Poly Ethylene), or PP (Poly Propylene).

The reflective layer 192 reflects light and may be made of a metal having a high reflectance such as silver (Ag), aluminum (Al), or titanium (Ti) or a metal oxide having a high reflectance such as titanium oxide (TiO ₂ ) have.

The light control member 190 is formed entirely of a transparent film 191 and a reflective layer 192 is formed on the transparent film 191 in a certain region. The area where only the transparent film 191 is located becomes the transmissive part B that transmits light and the area where the reflective layer 192 is located on the transparent film 191 becomes the reflective part A that reflects the light.

The reflective portion A and the transmissive portion B of the light control member 190 are divided into the light control member 190 and the reflective portion A and the transmissive portion B is located on the other side.

The reflective portion A or the transmissive portion B of the light control member 190 is aligned on the lower portion of the light guide plate 120 by driving the motor portions 195a and 195b to which the light control member 190 is fixed .

The operation of the light control member 190 and the motor units 195a and 195b will now be described.

FIGS. 5 and 6 are views illustrating the operation of the light control member and the motor unit according to an embodiment of the present invention.

5A, a light source 130 is disposed on one side of the light guide plate 120 and a light control member 190 is connected to the motor units 195a and 195b on one side of the light guide plate 120 do. The light control member 190 is operated in a state in which the transmissive portion B is aligned with the lower portion of the light guide plate 120. [ If the user selects the double-sided mode in which images are implemented on both sides, the light control member 190 implements the image with the transmissive portions B aligned.

5 (b), when the user selects a cross-sectional mode in which the image is implemented on the cross section, the motor portions 195a and 195b connected to the light control member 190 are operated to control the light control member 190, Is wound in one direction. The transmission portion B of the light control member 190 is wound by the motor portion 195b disposed on the right side and the reflection portion B of the light control member 190 wound on the motor portion 195a disposed on the left side, (A) is spread to the lower side of the light guide plate 120. [

5 (c), when the reflection portion A of the light control member 190 is aligned below the light guide plate 120, the operation of the motor portions 195a and 195b is stopped, A current is applied to the pixel electrode 130 to realize an image.

At this time, in the single-sided mode, about half of the amount of current applied to the light source 130 in the double-sided mode can be applied. This is because the light provided from the light source 130 is reflected by the reflector A disposed on one surface of the light guide plate 120 to realize an image.

Although the motor units 195a and 195b are disposed at the short sides of the light guide plate 120 in FIG. 5, the motor units 195a and 195b may be disposed at the long sides of the light guide plate 120, respectively.

6A, a light source 130 is disposed on one side of the light guide plate 120 and a light control member 190 is disposed on one side of the light guide plate 120 and connected to the motor units 195a and 195b . At this time, the motor units 195a and 195b may be disposed at the long sides of the light guide plate 120 on which the light sources 130 are disposed, respectively. In particular, in the case of the motor part 195b whose position overlaps with the light source 130, the light source 130 may be disposed.

The light control member 190 and the motor units 195a and 195b thus configured can be operated in the same manner as in FIG. 5 described above. That is, when the user selects the double-sided mode in which images are implemented on both sides, the light control member 190 implements the image in a state in which the transmissive portions B are aligned.

6 (b), when the user selects the cross-sectional mode in which the image is implemented on the cross section, the motor units 195a and 195b connected to the light control member 190 operate to control the light control member 190, Is wound in one direction. The transmission portion B of the light control member 190 is wound by the motor portion 195b disposed on the right side and the reflection portion B of the light control member 190 wound on the motor portion 195a disposed on the left side, (A) is spread to the lower side of the light guide plate 120. [

6 (c), when the reflective portion A of the light control member 190 is aligned with the lower portion of the light guide plate 120, the operation of the motor portions 195a and 195b is stopped, A current is applied to the pixel electrode 130 to realize an image.

Hereinafter, a method of driving a liquid crystal display according to an embodiment of the present invention will be described.

FIG. 7 is a flowchart illustrating a method of driving a liquid crystal display according to an embodiment of the present invention, and FIG. 8 is a flowchart illustrating a method of driving a liquid crystal display according to an exemplary embodiment of the present invention.

7 and 8 (a), a method of driving a liquid crystal display device of the present invention is such that a user applies power to a liquid crystal display device. Then, it is determined whether or not the liquid crystal display device is a two-sided mode. If the liquid crystal display device is in the two-sided mode, a current is supplied to the light source 130 to provide light.

At this time, the default state of the liquid crystal display device is set to the both-side mode, and the transmissive portion B of the light control member 190 connected to the motor portions 195a and 195b is aligned with the light guide plate 120. [

The light provided from the light source 130 is converted into a planar light source from the light guide plate 120 and the image is formed on the first and second liquid crystal panels 160 and 170 through the first and second optical members 140 and 150 Respectively.

On the other hand, referring to FIG. 8 (b), when it is determined that the liquid crystal display device is not the two-sided mode, the motor units 195a and 195b are driven. When the motor units 195a and 195b are driven, the light transmission unit B of the light control member 190 is wound on the right motor unit 195b and the light control member 190 The reflecting portion A of FIG.

Thus, the reflection portion A of the light control member 190 is aligned with the light guide plate 120, as shown in Fig. 8 (c). Then, the current applied to the light source 130 of the liquid crystal display device is reduced. This is because, as described above, since the light provided from the light source 130 is reflected by the reflective portion A and light is provided only to the end face of the liquid crystal display device, the amount of light can be lowered.

Accordingly, in the liquid crystal display device, light provided from the light source 130 is totally reflected by the light guide plate 120, and light reflected from the reflection portion A of the light control member 190 is transmitted through the first optical member 140, The liquid crystal panel 160 realizes a cross-sectional mode for realizing an image.

As described above, the liquid crystal display device and the driving method thereof according to an embodiment of the present invention can advantageously reduce the power consumption by adjusting the light amount of the backlight unit through the light control member and the motor unit when implementing the both- .

Table 1 below shows data obtained by comparing the brightness, the uniformity, and the white color coordinates of the conventional liquid crystal display device and the liquid crystal display device of the present invention.

Conventional liquid crystal display The
Liquid crystal display order Front panel Back panel Front panel Back panel 1 point luminance (Cd / m2) 5704 5710 10240 10170 9 point luminance (Cd / m2) 4981 5046 8579 8490 Luminance uniformity 2.88 2.99 2.72 2.89 White
Color coordinates CIE_x 0.263 0.263 0.269 0.269 CIE_y 0.243 0.242 0.255 0.255

Referring to Table 1, in contrast to the conventional liquid crystal display device not including the light control member and the motor portion, the liquid crystal display device of the present invention having the light control member and the motor portion has luminance uniformity and color coordinates Is about the same level, but the luminance has increased about twice.

Accordingly, when an image is formed only on the cross section of the front panel or the rear panel, the liquid crystal display of the present invention can exhibit a luminance level equivalent to that of the conventional liquid crystal display device even if the luminance of the light source is reduced to about half.

Therefore, the liquid crystal display device according to an embodiment of the present invention has an advantage that the light amount of the backlight unit can be reduced and the power consumption can be reduced by providing the light control member and the motor unit.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, It will be understood that the invention may be practiced. It is therefore to be understood that the embodiments described above are to be considered in all respects only as illustrative and not restrictive. In addition, the scope of the present invention is indicated by the following claims rather than the detailed description. Also, all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included within the scope of the present invention.

Claims (10)

A light guide plate;
A light source provided on at least one side of the light guide plate;
A first optical member positioned on one side of the light guide plate;
A first liquid crystal panel positioned on the first optical member;
A second optical member positioned on the other surface of the light guide plate;
A second liquid crystal panel positioned on the second optical member;
A light control member located on the light guide plate and including a transmissive portion for transmitting light and a reflective portion for reflecting light; And
And a motor portion for driving the light control member,
Wherein the light control member is positioned between the light guide plate and the first optical member or between the light guide plate and the second optical member.
delete delete The method according to claim 1,
Wherein the transmissive portion is a region where the transparent film is located, and the reflective portion is a region where the reflective layer is disposed on the transparent film.
The method according to claim 1,
Wherein the transmissive portion is positioned on one side of the light control member and the reflective portion is positioned on the other side of the light control member.
The method according to claim 1,
Wherein the motor unit is positioned on both sides of the light guide plate and facing each other.
The method according to claim 1,
Wherein the light control member is connected to the motor unit and driven by the motor unit.
A first optical member positioned on one side of the light guide plate, a first liquid crystal panel positioned on the first optical member, a second optical member positioned on the other side of the light guide plate, a second optical member positioned on the second side of the light guide plate, A light control member including a second liquid crystal panel disposed on the optical member, a light control member disposed on the light guide plate and transmitting the light, and a reflection unit reflecting the light, and a motor unit driving the light control member, Wherein the control member is positioned between the light guide plate and the first optical member or between the light guide plate and the second optical member,
Determining whether the liquid crystal display device is in a two-side mode or not;
Driving the motor unit provided on both sides of the light guide plate to align the transmissive portion or the reflective portion of the light control member;
Supplying a current corresponding to the double-side or single-side mode to a light source to provide light; And
And implementing an image in at least one of the first liquid crystal panel and the second liquid crystal panel through the light.
9. The method of claim 8,
When the liquid crystal display device is determined to be in the two-sided mode,
The motor unit is driven to align the transmissive portion of the light control member,
And providing light from the light source to implement an image in the first liquid crystal panel and the second liquid crystal panel.
9. The method of claim 8,
When it is determined that the liquid crystal display device is not in the two-sided mode,
The motor portion is driven to align the reflection portion of the light control member,
A current corresponding to the single-sided mode is supplied to the light source to provide light,
Wherein the image is implemented by either the first liquid crystal panel or the second liquid crystal panel.

Images