KR20080113761A - Bidirectional display device and its driving method - Google Patents

Abstract

Disclosed are a bidirectional display device and a driving method thereof for dimming a sub light source to minimize power consumption. The driving method of the bidirectional display device includes detecting a light from a main light source for supplying light to the main display panel, outputting a sensor signal, determining an on-off state of the main light source in response to the sensor signal, Outputting a first mode signal when it is off, and outputting a second mode signal when the main light source is on; a dimming driving signal for dimming and driving a sub light source that supplies light to the sub display panel in response to the first mode signal And outputting a normal driving signal for normally driving the sub light source in response to the second mode signal. Accordingly, power consumption of the bidirectional display device can be reduced by dimming the sub light source according to whether the main light source is turned on or off.

Description

Bidirectional display device and driving method thereof {DUAL DISPLAY APPARATUS AND METHOD OF DRIVING FOR THE SAME}

1 is an exploded perspective view illustrating a bidirectional display device according to an exemplary embodiment of the present invention.

FIG. 2 is a plan view illustrating the sub display unit of FIG. 1. FIG.

3 is a plan view illustrating the main display unit of FIG. 1.

4 is a cross-sectional view taken along the line II ′ of FIG. 3.

FIG. 5 is a block diagram illustrating a photo sensor, a main driving chip, a light source driving chip, and a light source in detail to show a method of driving a light source according to an exemplary embodiment of the present invention.

6 is a flowchart illustrating a method of driving a light source according to an embodiment of the present invention in detail.

<Description of the symbols for the main parts of the drawings>

110: main light source 111: light source driving chip

150: light blocking sheet 151: window

210: sub light source 300: main panel

321: light blocking film 330: the main driving chip

331: comparison control unit 332: mode control unit

333: light source dimming driving unit 400: sub-panel

500: photo sensor 600: bidirectional display device

IA: Display area MA: Main display area

The present invention relates to a bidirectional display device and a driving method thereof, and more particularly, to a bidirectional display device and a driving method thereof for supplying light to the section panel.

In general, the liquid crystal display is a flat panel display that displays an image using liquid crystal, and is thin and light, and has a low driving voltage and low power consumption. Therefore, the liquid crystal display is widely used throughout the industry. . Recently, however, a two-way liquid crystal display device has been developed that displays the same image or different images in both directions, instead of displaying the image in only one direction.

The bidirectional liquid crystal display device uses a display module consisting of two light units and two display panels to display images in both directions, and a bidirectional display module using one light unit and two display panels. And a two way type for displaying an image.

The twin type bidirectional display device includes a main unit consisting of a main panel and a main light source, and a sub unit consisting of a sub panel and a sub light source. Small and medium sized display devices mainly use light emitting diodes (LEDs) having small size and excellent luminous efficiency as main and sub light sources.

Meanwhile, the main and sub panels may be formed in a section panel type that displays image information by dividing areas. For example, the sub-panel is divided into a main display area for displaying a main image and an indicator display area for always displaying an antenna, a message, a charge amount, a clock, and the like.

In the above section panel type, the information displayed in the indication display area is always displayed for the convenience of the user, but for this purpose, a large amount of power for driving the sub light source is always consumed.

For example, the indication image displayed in the indication display area may be implemented using a separate light source driving chip for driving the LED. In this case, even when the light source driving chip is implemented in a dimming mode, a current of about 1.5 mA or more is consumed to consume about 4.5 mW (3.0 V × 1.5 mA). Accordingly, about 108 mWh (4.5 mA x 24 h) of power consumption per day is required. On the other hand, a self-luminous OLED, which is a kind of display device, can achieve the same luminance and contrast ratio (C / R) as the indication region even at a current of about 1 mA or less.

Accordingly, power consumption of the display device is minimized by operating the sub unit in the dimming mode to the off mode.

Accordingly, the technical problem of the present invention is to solve such a conventional problem, and an object of the present invention is to provide a bidirectional display device for further minimizing power consumption by dimming the sub light source according to the lighting of the main light source.

Another object of the present invention is to provide a method of driving the bidirectional display device.

In order to achieve the above object of the present invention, a bidirectional display device includes a main display unit having a main light source for generating main light and a main display panel for displaying an image using the main light, and a sub light. A sub display unit having a sub light source and a sub display panel for displaying an image using the sub light, a light source driver for outputting a light source driving signal for driving the main and sub light sources, and a main display panel; A photo sensor for sensing main light and outputting a sensor signal, and in response to the sensor signal, outputting a first mode signal when the main light source is off, and outputting a second mode signal when the main light source is on; A display unit driver configured to output a dimming driving signal for dimming the sub light source in response to a first mode signal It includes.

In accordance with another aspect of the present invention, there is provided a method of driving a bidirectional display device, the method comprising: detecting a light from a main light source supplying light to a main display panel and outputting a sensor signal to the sensor signal; In response, determining on-off of the main light source, outputting a first mode signal when the main light source is off, and outputting a second mode signal when the main light source is on, and outputting the first mode signal. Outputting a dimming driving signal for dimming a sub light source for supplying light to the sub display panel in response to a call; and outputting a normal driving signal for normally driving the sub light source in response to the second mode signal; Steps.

According to the bidirectional display device and a driving method thereof, the sub-light source is dimmed according to whether the main light source is turned on or off using the light source dimming driving circuit built in the panel driving chip, thereby reducing power consumption of the bidirectional display device. .

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

1 is an exploded perspective view illustrating a bidirectional display device according to an exemplary embodiment of the present invention.

Referring to FIG. 1, the bidirectional display device 600 according to an exemplary embodiment of the present disclosure may drive a main display assembly displaying a main image, a subdisplay assembly displaying a sub image, and main and sub light sources 110 and 210. Including a light source driving chip 111, a dual-type display device for displaying an image in both directions.

The main display assembly includes a main display unit 300 including a main display panel and a main driving chip 330, and a main light source unit.

In detail, the main display panel displays a main image using light supplied from the main light source unit. The main display panel includes a first substrate 310, a second substrate 320 facing the first substrate 310, and a first liquid crystal layer disposed between the first substrate 310 and the second substrate 320. (Not shown).

The first substrate 310 is a transparent glass substrate in which a thin film transistor (TFT), which is a switching element, is formed in a matrix form. Data and gate lines are respectively connected to the source and gate terminals of the TFTs, and a pixel electrode made of a transparent conductive material is connected to the drain terminal.

The second substrate 320 includes an RGB color filter for realizing color and a common electrode facing the pixel electrode. The color filter may be formed on the first substrate 310.

The first liquid crystal layer is formed of liquid crystal molecules having electrical and optical properties such as anisotropic dielectric constant and anisotropic refractive index disposed between the first substrate 310 and the second substrate 320.

When the power is applied to the gate terminal of the TFT such that the TFT is turned on, an electric field is formed between the pixel electrode and the common electrode. Due to the electric field, the arrangement of the liquid crystal molecules of the first liquid crystal layer disposed between the first substrate 310 and the second substrate 320 is changed, and the light transmittance is changed according to the arrangement of the liquid crystal molecules, thereby changing the liquid crystal display. The panel may display an image of a desired gray scale.

The main display panel is divided into a display area in which the TFT is formed to actually display an image, and a peripheral area surrounding an outer portion of the display area.

The main driving chip 330 generates a driving signal for driving the main display panel in response to various control signals applied from the outside. The main driving chip 330 is mounted on a portion of the peripheral area of the first substrate 310 of the main display panel. For example, the main driving chip 330 may be mounted on one end of the first substrate 310 by using a chip on glass (COG) process. For example, the main driving chip 330 may be formed as a single chip that outputs a data signal to the data line and outputs a gate signal to the gate line.

On the other hand, as in the embodiment of the present invention, the main driving chip 330 can drive the sub light source 210 by a driving current relatively lower than the driving current required for driving the main light source 110. This will be described later.

The main light source unit includes a main light source 110 for generating light and a main light guide part for guiding the light from the main light source 110 and outputting the light to the main display panel. The main light source 110 may include a plurality of light emitting diodes. The number of main light sources 110 may vary depending on the size of the main display panel and the luminance required. Meanwhile, as an example, the main light guide part may include a light guide plate 120, a diffusion sheet 130, and a prism sheet 140.

The sub display assembly includes a sub display unit 400 including a sub display panel and a sub driving chip 430, and a sub light source unit.

The sub display panel displays a sub image using light supplied from the sub light source unit. The sub display panel includes a third substrate 410, a fourth substrate 420 facing the third substrate 410, and a second liquid crystal layer disposed between the third substrate 410 and the fourth substrate 420. (Not shown). The third and fourth substrates 410 and 420 of the sub display panel may be the same as the first and second substrates 310 and 320 of the main display panel, and the second liquid crystal layer may be formed to be the same as the first liquid crystal layer. The detailed description thereof will be omitted.

The sub display panel is divided into a display area in which the TFT is formed to actually display an image, and a peripheral area surrounding an outer portion of the display area.

The sub driving chip 430 generates a driving signal for driving the sub display panel in response to various control signals applied from the outside. The sub driving chip 430 may be mounted on a portion of the peripheral area of the third substrate 410 of the sub display panel. Unlike this, as an example, the sub driving chip 430 and the main driving chip 330 may be formed as a single chip.

The sub light source unit includes a sub light source 210 for generating light and a sub light guide part for guiding light from the sub light source 210 and outputting the light to the sub display panel. The sub light source 210 may include at least one light emitting diode. For example, the number of sub light sources 210 may be formed to be smaller than the number of main light sources 110. For example, the sub light guide part may include a light guide plate 220, a diffusion sheet 230, and a prism sheet 240.

The light source driving chip 111 outputs a light source driving signal for driving the sub light source 210 and the main light source 110. The light source driving chip 111 of the present exemplary embodiment normally drives the main and sub light sources 110 and 210 together when the main light source 110 is turned on in response to the control signal of the main driving chip 330. Details thereof will be described later.

The main display assembly and the sub display assembly may be formed as separate modules. On the other hand, the main and sub light source unit may further include a reflection sheet (not shown) disposed at the bottom of the main and sub light guide portion in order to emit light from each light source in one direction.

The bidirectional display device 600 according to the present invention dims the sub light source 210 using the main driving chip 330, thereby minimizing the power consumed when the sub light source 210 is driven and through the sub display panel. You can always display the image.

FIG. 2 is a plan view illustrating the sub display unit of FIG. 1. FIG.

1 and 2, the main and sub display panels of the present invention may be divided into a display area for displaying an image and a peripheral area surrounding an outer edge of the display area, respectively. In addition, the bidirectional display device 600 according to the present invention may include a section panel in which the display area is divided into a main display area and an indication display area.

Referring to FIG. 2, for example, the sub display panel constituting the sub display unit may be divided into a display area DA1 and a peripheral area EA1.

The display area DA1 may be divided into a main display area MA and an indication display area IA. Specifically, the main display area MA is an area for displaying a main image such as an image signal and text information, and the indication display area IA is an area for displaying an indication image such as an antenna, a battery, a clock, and a date.

In the peripheral area EA1, a sub driving chip 430 may be disposed to apply an image driving signal to the display area DA1. For example, the sub driving chip 430 may be disposed at one end of the sub display panel adjacent to the main display area MA.

In this case, in the case of the sub display panel, the indication image is always displayed on the indication display area IA for the convenience of the user. To this end, the bidirectional display device 600 according to the present invention may always display an indication image on the sub display panel by driving the sub light source 210 on or dimming according to whether the main light source 110 is turned on.

3 is a plan view illustrating the main display unit of FIG. 1.

4 is a cross-sectional view taken along the line II ′ of FIG. 3.

1 and 3, as in the exemplary embodiment of the present invention, the bidirectional display device 600 may further include a photo sensor 500 for determining whether the main light source 110 is turned on. For example, the photo sensor 500 may be formed on the main display panel to directly detect light from the main light source 110.

In detail, the main display unit 300 may include the main display panel, the main driving chip 330, and the photo sensor 500. The main display panel is divided into a display area DA2 displaying a main image and a peripheral area EA2 surrounding the display area DA2. The main driving chip 330 may be disposed in the peripheral area DA2 corresponding to one end of the display area DA2.

The photo sensor 500 is a kind of thin film transistor and includes a channel layer, a sensor gate electrode, a sensor source electrode, and a sensor drain electrode that sense light from the main light source 110. The sensor gate electrode receives an arbitrary pulse signal from the outside. The channel layer senses light from the main light source 110 and electrically connects the sensor source electrode and the sensor drain electrode when the detected light intensity is greater than or equal to a predetermined reference value. The photo sensor 500 integrates the current flowing therein through the internal integrator circuit through the above process, and outputs a voltage sensor signal to the main driving chip 330.

For example, the photo sensor 500 may be formed in a portion of the peripheral area EA2 to correspond to the outside of the signal line extending from the main driving chip 330 in the direction of the display area DA2.

3 and 4, the main display panel includes first and second substrates 310 and 320 facing each other so as to accommodate the first liquid crystal layer in cross section. The second substrate 320 includes a color filter 322 formed in a central portion corresponding to the display area DA2 and a light blocking film 321 formed in an outer portion corresponding to the peripheral area EA2.

As in one embodiment of the present invention, the photo sensor 500 may be formed on one end of the first substrate 310 to correspond to the light blocking film 321. For example, the photo sensor 500 may be formed in plural, and may include at least three independent thin film transistors for accurate light sensing.

1 and 5, the main light source unit 100 includes a main light source 110 and the main light guide parts 120, 130, and 140.

The main light source unit 100 of the present exemplary embodiment further includes a light blocking sheet 150 formed at a position corresponding to the peripheral area EA2 of the main display panel. The light blocking sheet 150 is formed between the main display panel and the main light source unit 100. The light blocking sheet 150 blocks light from being emitted to the peripheral area EA2 of the main display panel. For example, the light blocking sheet 150 may be made of a black tape material for blocking light.

As in one embodiment of the present invention, in order to sense the light from the main light source 110, the photo sensor 500 formed in the peripheral area (EA2), the light blocking sheet 150 may partially transmit the light. A window 151 may be formed. The window 151 may be an opening formed by removing a portion of the light blocking sheet 150 to correspond to a position where the photo sensor 500 is formed. Accordingly, the photo sensor 500 detects light transmitted upward through the window 151 among the light from the main light source 110, and outputs a sensor signal for controlling the driving mode of the sub light source 210. Can be.

FIG. 5 is a block diagram illustrating a photo sensor, a main driving chip, a light source driving chip, and a light source in detail to show a method of driving a light source according to an exemplary embodiment of the present invention.

1 and 5, the main driving chip 330 and the light source driving chip 111 are controlled in response to light detected from the main light source 110 to drive the main and sub light sources 210. Look specifically at.

As in the exemplary embodiment of the present invention, the bidirectional display device 600 includes a photo sensor 500, a main driving chip 330, a light source driving chip 111, and light sources 110 and 210.

The photo sensor 500 detects light from the main light source 110 and outputs a sensor signal SEN_S. Specifically, the photo sensor 500 changes the current value flowing inside the device according to the brightness of the light, integrates the current value through the internal integrator circuit, and outputs the current signal as the sensor signal SEN_S having a predetermined voltage.

The photo sensor 500 according to the present invention outputs a first sensor signal in response to the first light amount emitted when the main light source 110 is off, and responds to a second light amount emitted when the main light source 110 is on. The second sensor signal can be output. That is, the photo sensor 500 of the present exemplary embodiment outputs different sensor signals SEN_S to the main driving chip 330 according to the luminance of the light emitted from the main light source 110.

For example, the main light source 110 emits light of the first light amount during the off driving, and emits light of the second light amount during the on driving. The brightness of the second light amount is higher than the brightness of the first light amount. The photo sensor 500 outputs the first sensor signal in response to the first light amount, and outputs the second sensor signal in response to the second light amount. In this case, the second sensor signal has a smaller value than the first sensor signal. That is, the sensor signal output when the main light source 110 is on has a smaller value than the sensor signal output when the main light source 110 is off. As described above, the sensor signal SEN_S output from the photo sensor 500 of the present exemplary embodiment may be inversely related to the intensity of the detected light.

The main driving chip 330 includes a panel driver, a comparison controller 331, a mode controller 332, and a light source dimming driver 333.

The panel driver outputs an image driving signal for driving the main display panel. For example, the panel driver may include the gate and data driving signals.

The comparison controller 331 compares the sensor signal SEN_S with a reference signal preset therein and outputs a comparison control signal COM_S in response to the sensor signal SEN_S. The comparison control unit 331 outputs a comparison control signal COM_S by comparing the reference signal with the sensor signal SEN_S whose output value varies depending on whether the internal light source is turned on or not.

As in the present embodiment, the reference signal may have a value corresponding to an intermediate magnitude between the first sensor signal and the second sensor signal. For example, the reference signal may have a value smaller than the first sensor signal and larger than the second sensor signal. Accordingly, in response to the sensor signal SEN_S that varies depending on whether the internal light source is turned on, a control signal for selecting the driving mode of the light source can be output.

In detail, the comparison control unit 331 compares the reference signal with the sensor signal SEN_S, and outputs a comparison control signal COM_S. For example, the comparison controller 331 includes a signal comparator (not shown) for comparing the sensor signal SEN_S with the reference signal. The comparison control signal COM_S may include first and second comparison signals.

For example, when the sensor signal SEN_S is larger than the reference signal, the first comparison signal is output. When the sensor signal SEN_S is smaller than the reference signal, the second comparison signal is output. As described above, the comparison controller 331 compares and determines whether the sensor signal SEN_S from the photo sensor 500 sensed in real time is larger or smaller than the reference signal, and outputs a comparison control signal COM_S.

The mode controller 332 outputs a mode selection signal for selecting a control mode in response to the comparison control signal COM_S. The mode selection signal includes first and second mode signals MOD_S1 and MOD_S2 for operating the light sources 110 and 210 in different control modes.

In detail, the mode controller 332 turns on the light source dimming driver 333 and outputs a first mode signal MOD_S1 for turning off the light source driving chip 111 in response to the first comparison signal. In response to the second comparison signal, the mode controller 332 turns off the light source dimming driver 333 and outputs a second mode signal MOD_S2 for turning on the light source driving chip 111. For example, the mode controller 332 may output the first and second mode signals MOD_S1 and MOD_S2 in digital form, the first mode signal MOD_S1 is 0, and the second mode signal MOD_S2 may be one. have.

The light source dimming driver 333 outputs a dimming driving signal DIM_S for dimming the sub light source 210 in response to the first mode signal MOD_S1. For example, the dimming driving signal DIM_S may be about 0.1 to 0.4 mA. Meanwhile, the light source dimming driver 333 is turned off when the second mode signal MOD_S2 is output.

The light source driving chip 111 outputs a light source driving signal DRV_S for normally driving the sub light sources 110 and 210 in response to the second mode signal MOD_S2. For example, the light source driving signal DRV_S may be about 15 mA. On the other hand, the light source driving chip 111 is turned off when the first mode signal MOD_S1 is output.

The main light source 110 generates light in response to the light source driving signal DRV_S. That is, the main light source 110 generates light having the same luminance at all times during the on operation in response to the light source driving signal DRV_S.

The sub light source 210 generates light in response to the dimming driving signal DIM_S and the light source driving signal DRV_S.

Specifically, the sub light source 210 operates in a dark mode that generates light corresponding to the low luminance in response to the dimming driving signal DIM_S. That is, when the off-mode driving of the main light source 110, the sub light source 210 is driven in the low brightness mode.

In response to the light source driving signal DRV_S, the sub light source 210 operates in a bright mode that generates light corresponding to high luminance. That is, when driving the full mode of the main light source 110, the sub light source 210 is driven in a high brightness mode.

In total, the bidirectional liquid crystal display 600 may drive the main and sub light sources 110 and 210 in the bright mode and dimm the sub light source 210 in the dark mode under the control of the mode controller 332. Can be.

That is, in the dark mode corresponding to the off driving of the main light source 110, the sub-light source (DIM_S) is used by the dimming driving signal DIM_S having a current value smaller than the light source driving signal DRV_S through the light source dimming driving unit 333. The dimming driving may be performed. Accordingly, power consumption for displaying an image through the sub display panel can be minimized.

The main driving chip 330 may further include a signal converter (not shown) for converting a control signal from the mode controller 332. The signal converter decodes the first and second mode signals MOD_S1 and MOD_S2 in digital form, and outputs a corresponding analog form signal. For example, the signal converter may be a decoder circuit embedded in the main driving chip 330.

6 is a flowchart illustrating a method of driving a light source according to an embodiment of the present invention in detail.

5 and 6, in the light source driving method of the bidirectional display device 600 according to an exemplary embodiment of the present invention, sensing the main light from the main light source 110 and outputting a sensor signal SEN_S ( S100, comparing the sensor signal SEN_S with the reference signal to determine an on-off state of the main light source 110 (S110). When the sensor signal SEN_S is equal to or greater than the reference signal, the first mode signal (S110) is determined. Outputting MOD_S1 (S120), outputting a dimming driving signal DRV_S (S130), and dimming driving the sub light source 210 (S140).

On the other hand, if the sensor signal SEN_S is less than or equal to the reference signal, the step S150 of outputting the second mode signal MOD_S2, the step S160 of outputting the light source driving signal DIM_S, and the sub light source 210 may be performed. A normal driving step (S170) is included.

In detail, in operation S100, the photo sensor 500 detects main light from the main light source 110. The photo sensor 500 outputs the sensor signal SEN_S in response to the amount of light of the main light.

In operation S110, the comparison controller 331 compares the sensor signal SEN_S with the preset reference signal. The comparison controller 331 compares the magnitude of the sensor signal SEN_S and the reference signal, and outputs a comparison control signal COM_S corresponding thereto.

In operation S120, when the sensor signal SEN_S is greater than or equal to the reference signal as determined in operation S110, the mode controller 332 responds to the first comparison signal from the comparison controller 331, and thus, the first mode signal MOD_S1. ) Is output to the light source dimming driver 333. Here, the case where the sensor signal SEN_S is greater than or equal to the reference signal means that the main light source 110 is driven off. That is, when the main light source 110 is off, the mode controller 332 outputs the first mode signal MOD_S1 for driving the light source dimming driver 333.

In operation S130, the light source dimming driver 333 outputs the dimming driving signal DIM_S to the sub light source 210 in response to the first mode signal MOD_S1. That is, when the main light source 110 is off, the light source dimming driver 333 dims the sub light source 210. For example, the dimming driving signal DIM_S is a current output from the light source dimming driver 333 and may have a value of about 0.1 to 0.4 mA.

In operation S140, the sub light source 210 generates light in response to the dimming driving signal DIM_S from the light source dimming driver 333. That is, the sub light source 210 generates light having a relatively lower luminance than the light emitted by the light source driving signal DRV_S in response to the dimming driving signal DIM_S which is a lower current than the light source driving signal DRV_S. Let's do it.

In operation S150, when the sensor signal SEN_S is less than or equal to the reference signal as determined in operation S110, the mode controller 332 responds to the second comparison signal from the comparison controller 331, and thus, the second mode signal MOD_S2. ) Is output to the light source driving chip 111. Here, the case where the sensor signal SEN_S is less than or equal to the reference signal means that the main light source 110 is driven on. That is, when the main light source 110 is on, the mode controller 332 outputs the second mode signal MOD_S2 for driving the light source driving chip 111.

In operation S160, the light source driving chip 111 outputs the light source driving signal DRV_S to the sub light source 210 in response to the second mode signal MOD_S2. That is, when the main light source 110 is turned on, the light source driving chip 111 outputs a light source driving signal DRV_S for driving the main light source 110, thereby simultaneously driving the sub light source 210 normally. For example, the light source driving signal DRV_S may have a value of about 15 mA as a current output from the light source driving chip 111.

In operation S170, the sub light source 210 generates light in response to the light source driving signal DRV_S from the light source driving chip 111. As such, when the main light source 110 is turned on, the sub light source 210 may be normally driven together with the main light source 110 by the light source driving chip 111.

As such, according to whether the main light source 110 is turned on, the current level of the driving signal supplied to the sub light source 210 may be adjusted. As in the present exemplary embodiment, when the main light source 110 is turned off, the sub light source (not shown) is used by using the light source dimming driver 333 built in the main driving chip 330 instead of the light source driving chip 111 that consumes a lot of power. The dimming operation may be performed. Accordingly, power consumption of the sectional bidirectional display device 600 can be minimized.

In this case, in order to always display an indication image using the light from the sub light source 210 through the sub display panel, in the bright mode corresponding to the full mode of the main light source 110, the sub light source 210 ) Is normally turned on together with the main light source 110, and in the dark mode corresponding to the off mode of the main light source 110, the sub light source 210 is dimmed and turned on.

In the present invention, by using the photo sensor 500 to detect the light from the main light source 110 to determine the on and off of the main light source 110, depending on whether the main light source 110 is turned on of the sub light source 210 The driving mode can be controlled differently. Accordingly, the indication image may be displayed at all times using the sub display panel, and the power consumed when driving the light source may be minimized.

According to such a method of driving a light source and a bidirectional display device for performing the same, when the light source of the sectional bidirectional display device including the main and sub display units is driven, the sub light source is turned on or dimmed according to whether the main light source is turned on. Accordingly, the image may be always displayed using the sub display panel, and the power consumed when driving the light source may be minimized.

Although the detailed description of the present invention has been described with reference to the preferred embodiments of the present invention, those skilled in the art or those skilled in the art will have the idea of the present invention described in the claims to be described later. It will be understood that various modifications and variations can be made in the present invention without departing from the scope of the invention.

Claims (8)

A main display unit having a main light source for generating main light and a main display panel for displaying an image using the main light; A sub display unit having a sub light source for generating sub light and a sub display panel for displaying an image using the sub light; A light source driver configured to output a light source driving signal for driving the main and sub light sources; A photo sensor formed on the main display panel and configured to detect the main light and output a sensor signal; And In response to the sensor signal, a first mode signal is output when the main light source is off; a second mode signal is output when the main light source is on; and dimming driving the sub light source in response to the first mode signal. And a display unit driver for outputting a dimming drive signal for driving the display device. The display unit of claim 1, wherein the display unit driving unit A panel driver which outputs an image driving signal for driving the main and sub display panels; A comparison control unit comparing the sensor signal with a preset reference signal to output a first comparison signal when the sensor signal is larger than the reference signal and to output a second comparison signal when the sensor signal is smaller than the reference signal; A mode controller outputting a first mode signal in response to the first comparison signal and outputting a second mode signal in response to the second comparison signal; And And a light source dimming driver for outputting the dimming driving signal in response to the first mode signal. The display device of claim 1, wherein the main display panel comprises: A first substrate disposed on an upper side of the main light source, surrounding a display area for displaying an image and an outer portion of the display area, and divided into a peripheral area in which the photo sensor is formed; A second substrate facing the first substrate and having a light blocking film corresponding to the peripheral region; And And a liquid crystal layer interposed between the first substrate and the second substrate. The method of claim 3, wherein the main display unit And a light blocking tape formed between the main display panel and the main light source corresponding to the peripheral area, the light blocking tape having a window for transmitting light corresponding to the position where the photo sensor is formed. Device. The bidirectional display device according to claim 1, wherein the sub display panel is a section panel divided into a main display area for displaying a main image and an indication display area for displaying an indication image. Sensing a light from a main light source supplying light to the main display panel and outputting a sensor signal; Determining on-off of the main light source in response to the sensor signal; Outputting a first mode signal when the main light source is off, and outputting a second mode signal when the main light source is on; Outputting a dimming driving signal for dimming a sub light source for supplying light to a sub display panel in response to the first mode signal; And And outputting a normal driving signal for normally driving the sub light source in response to the second mode signal. The method of claim 6, wherein the determining of the on-off of the main light source When the sensor signal is larger than a preset reference signal, the main light source is determined to be off, and when the sensor signal is smaller than the reference signal, the main light source is determined to be on. Way. The method of claim 6, wherein the dimming driving signal has a smaller magnitude than the normal driving signal.

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