KR20160101572A - Image display apparatus and power saving method thereof - Google Patents

Abstract

The present invention relates to an image display apparatus of a mobile terminal to reduce power consumption when a PWM-type display device is driven in an outdoor visibility mode, and a power consumption saving method thereof. An image mode and gray scale are determined when image data is inputted. When the image mode is the outdoor visibility mode, low gray scale data drives a data line with the pulse width and current intensity used for normal mode whereas high scale data drives data line with current and pulse width used for outdoor visibility mode. So, power consumption generated in operating the outdoor visibility mode is reduced.

Description

TECHNICAL FIELD [0001] The present invention relates to a video display apparatus and a method of reducing power consumption of the video display apparatus.

The present invention relates to an image display apparatus capable of reducing power consumption when a PWM-type display is driven in an outdoor visibility mode, and a power consumption reduction method thereof.

A terminal can be divided into a mobile terminal (mobile / portable terminal) and a stationary terminal according to whether the terminal can be moved. The mobile terminal can be divided into a handheld terminal and a vehicle mounted terminal according to whether the user can directly carry the mobile terminal.

The functions of mobile terminals are diversified. For example, there are data and voice communication, photographing and video shooting through a camera, voice recording, music file playback through a speaker system, and outputting an image or video on a display unit. Some terminals are equipped with an electronic game play function or a multimedia player function. In particular, modern mobile terminals can receive multicast signals that provide visual content such as broadcast and video or television programs.

Such a terminal has been implemented in the form of a multimedia device having a combination of functions such as photographing and photographing of a moving picture, reproduction of a music or video file, reception of a game and broadcasting, etc. .

In order to support and enhance the functionality of such terminals, it may be considered to improve the structural and / or software parts of the terminal.

Recently, portable mobile devices are making efforts to improve the outdoor visibility of displays. In order to improve the outdoor visibility, the method of increasing the brightness to the maximum brightness that the display can usually use is used, but the power consumption is increased and the battery is wasted. For example, the Samsung Galaxy Gear Pit has an outdoor mode, but it is limited to 5 minutes, which shows that it consumes a lot of power.

That is, in the case of a PWM-driven display in which the length of the pulse width is adjusted (PWM) to express the gradation, the intensity of the current must be increased in order to improve outdoor visibility. The reason for this is that the PWM driving method can not express the high luminance for outdoor visibility because of the limitation of the time for which the pulse length can be extended (the time allocated for expressing one frame).

However, in order to increase the outdoor visibility, when the intensity of the current is increased, the power consumption is increased and the consumption of the battery is large. Therefore, a power consumption reduction method suitable for the PWM driving method is indispensable.

An object of the present invention is to provide an image display apparatus and a power consumption reduction method thereof that can reduce power consumption when a PWM type display apparatus is driven in an outdoor visibility mode.

It is another object of the present invention to provide an image display apparatus capable of driving a display device with different current intensities at a low gradation and a high gradation in an outdoor visibility mode and a power consumption reduction method thereof.

According to an aspect of the present invention, there is provided an image display apparatus including: a display panel including a plurality of pixels connected to a scan line and a data line; A scan driver driving a scan line; A data driver for driving a delta line; And a control unit for discriminating the low gradation and the high gradation of the image data in the outdoor visibility mode and controlling the data driving unit to drive the data line with different current intensities at the low gradation and the high gradation.

 The controller discriminates the image data by the low gray level and the high gray level based on the gray level that gives the maximum brightness in the normal mode.

The control unit controls the data lines to drive the low gray level data with current intensity and pulse width used in the normal mode and controls the high gray level data to drive the data lines with the current intensity and pulse width in the outdoor visibility mode.

The controller may control the difference between the maximum brightness of the normal mode and the minimum brightness of the outdoor visibility mode to be 2 to 3 gradations or less when the low gradation data of the outdoor visibility mode is driven by the current of the normal mode and the pulse width.

The controller divides the M gradations by the quantization coefficient N determined according to the brightness of the external light to reduce the number of (M / N) gradations in the low gradation representation of the outdoor visibility mode.

Wherein the control unit determines whether the image data is low gray or high gray based on the maximum brightness that can be obtained in the normal mode and outputs a gray level determination signal; An image processor for converting the image data according to the current intensity and the pulse of the normal mode or the outdoor visibility mode according to the mode selection signal and the gradation determination signal; A frame memory for storing the image data converted by the image processor and transmitting the stored image data to the data driver; And a reset unit for outputting a reset signal to the frame memory according to the gray-level determination signal and the mode selection signal output from the image determination unit.

According to an aspect of the present invention, there is provided a method of reducing power consumption of a video display device, comprising: determining a video mode when video data is input; Determining gradation of the image data; And driving the data line with different current intensities for the determined low gray level and high gray level data when the image mode is the outdoor visibility mode.

The low gradation and the high gradation of the image data are determined based on the gradations giving the maximum brightness in the normal mode.

Driving the data line includes driving a data line with current intensity and pulse width using the low gray level data in the normal mode; And driving the data line with the current intensity and the pulse width of the outdoor visibility mode in the high gray scale data.

When the low tone data of the outdoor visibility mode is driven by the current of the normal mode and the pulse width, the difference between the maximum brightness of the normal mode and the minimum brightness of the outdoor visibility mode is controlled to be 2 to 3 gradations or less.

And converting the M gradations to M / N gradations in the low gradation representation of the outdoor visibility mode. Here, N is a quantization coefficient determined according to the brightness of external light.

The video display device and the power saving method thereof according to the present invention are driven by the current intensity and pulse width used in the normal mode when the low gradation data is used in the outdoor visibility mode and the current intensity and the current intensity when the high gradation data is used. By driving the data line with the pulse width, it is possible to reduce the power consumption in the outdoor visibility mode. In particular, in the low gradation representation of the visibility mode, the M gradations are reduced to M / N gradation representation (quantization) There is an effect that can be reduced.

1 is a block diagram of a mobile terminal including a video display device related to the present invention;
2 is a graph showing the current intensity of the PWM pulse driving the display panel in the normal mode and the outdoor visibility mode
3 is a block diagram of a video display device according to a first embodiment of the present invention;
4 is a block diagram of a video display device according to a second embodiment of the present invention;
5 is a flowchart illustrating a power saving method in a visibility mode operation in a video display device according to an exemplary embodiment of the present invention.
Figures 6 and 7 illustrate the concept of driving a data line using two or more current intensities in an outdoor visibility mode.
8 is an embodiment in which gray level quantization is performed in a low gray level in the outdoor visibility mode.
Fig. 9 is an exemplary diagram for driving pulses of one frame at different gradation levels in the outdoor visibility mode at different current intensities. Fig.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings, in which like or similar elements are denoted by the same or similar reference numerals, and redundant description thereof will be omitted. The suffix "module" and " part "for the components used in the following description are given or mixed in consideration of ease of specification, and do not have their own meaning or role. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed. , ≪ / RTI > equivalents, and alternatives.

The mobile terminal described in this specification includes a mobile phone, a smart phone, a laptop computer, a digital broadcasting terminal, a personal digital assistant (PDA), a portable multimedia player (PMP), a navigation device, a slate PC A tablet PC, an ultrabook, a wearable device such as a smartwatch, a smart glass, and a head mounted display (HMD). have.

However, it will be appreciated by those skilled in the art that the configuration according to the embodiments described herein may be applied to fixed terminals such as a digital TV, a desktop computer, a digital signage, and the like, will be.

1 is a block diagram illustrating a mobile terminal according to the present invention.

The mobile terminal 100 includes a wireless communication unit 110, an input unit 120, a sensing unit 140, an output unit 150, an interface unit 160, a memory 170, a control unit 180, And the like. The components shown in FIG. 1 are not essential for implementing a mobile terminal, so that the mobile terminal described herein may have more or fewer components than the components listed above.

The wireless communication unit 110 is a unit that enables wireless communication between the mobile terminal 100 and the wireless communication system or between the mobile terminal 100 and another mobile terminal 100 or between the mobile terminal 100 and an external server. The above modules may be included.

The wireless communication unit 110 may include at least one of a broadcast receiving module 111, a mobile communication module 112, a wireless Internet module 113, a short range communication module 114, and a location information module 115.

The input unit 120 includes a camera 121 or an image input unit for inputting a video signal, a microphone 122 for inputting an audio signal, an audio input unit, a user input unit 123 for receiving information from a user A touch key, a mechanical key, and the like). The voice data or image data collected by the input unit 120 may be analyzed and processed by a user's control command.

The sensing unit 140 may include at least one sensor for sensing at least one of information in the mobile terminal, surrounding environment information surrounding the mobile terminal, and user information. For example, the sensing unit 140 may include a proximity sensor 141, an illumination sensor 142, a touch sensor, an acceleration sensor, a magnetic sensor, A G-sensor, a gyroscope sensor, a motion sensor, an RGB sensor, an infrared sensor, a finger scan sensor, an ultrasonic sensor, A microphone 226, a battery gauge, an environmental sensor (for example, a barometer, a hygrometer, a thermometer, a radiation detection sensor, A thermal sensor, a gas sensor, etc.), a chemical sensor (e.g., an electronic nose, a healthcare sensor, a biometric sensor, etc.). Meanwhile, the mobile terminal disclosed in the present specification can combine and utilize information sensed by at least two of the sensors.

The output unit 150 includes at least one of a display unit 151, an acoustic output unit 152, a haptic tip module 153, and a light output unit 154 to generate an output related to visual, auditory, can do. The display unit 151 may have a mutual layer structure with the touch sensor or may be integrally formed to realize a touch screen.

The interface unit 160 serves as a path to various types of external devices connected to the mobile terminal 100. The interface unit 160 is connected to a device having a wired / wireless headset port, an external charger port, a wired / wireless data port, a memory card port, And may include at least one of a port, an audio I / O port, a video I / O port, and an earphone port.

The memory 170 may store data supporting various functions of the mobile terminal 100, a plurality of application programs (application programs or applications), data for operation of the mobile terminal 100, and commands.

In addition to the operations related to the application program, the control unit 180 typically controls the overall operation of the mobile terminal 100. The control unit 180 may process or process signals, data, information, and the like input or output through the above-mentioned components, or may drive an application program stored in the memory 170 to provide or process appropriate information or functions to the user.

In addition, the controller 180 may control at least some of the components illustrated in FIG. 1 to operate an application program stored in the memory 170, or may operate at least two or more of the components in combination with each other.

The power supply unit 190 receives external power and internal power under the control of the controller 180 and supplies power to the components included in the mobile terminal 100. The power supply unit 190 includes a battery, which may be an internal battery or a replaceable battery.

Hereinafter, the components listed above will be described in more detail with reference to FIG. 1 before explaining various embodiments implemented through the mobile terminal 100 as described above.

First, referring to the wireless communication unit 110, the broadcast receiving module 111 of the wireless communication unit 110 receives broadcast signals and / or broadcast-related information from an external broadcast management server through a broadcast channel. The broadcast channel may include a satellite channel and a terrestrial channel. Two or more broadcast receiving modules may be provided to the mobile terminal 100 for simultaneous broadcast reception or broadcast channel switching for at least two broadcast channels.

The broadcast management server may refer to a server for generating and transmitting broadcast signals and / or broadcast related information, or a server for receiving broadcast signals and / or broadcast related information generated by the broadcast management server and transmitting the generated broadcast signals and / or broadcast related information. The broadcast signal may include a TV broadcast signal, a radio broadcast signal, a data broadcast signal, and a broadcast signal in which a data broadcast signal is combined with a TV broadcast signal or a radio broadcast signal.

The mobile communication module 112 may be a mobile communication module or a mobile communication module such as a mobile communication module or a mobile communication module that uses technology standards or a communication method (e.g., Global System for Mobile communication (GSM), Code Division Multi Access (CDMA), Code Division Multi Access 2000 (Enhanced Voice-Data Optimized or Enhanced Voice-Data Only), Wideband CDMA (WCDMA), High Speed Downlink Packet Access (HSDPA), High Speed Uplink Packet Access (HSUPA), Long Term Evolution (LTE) And an external terminal, or a server on a mobile communication network established according to a long term evolution (e. G., Long Term Evolution-Advanced).

The wireless signal may include various types of data depending on a voice call signal, a video call signal or a text / multimedia message transmission / reception.

The wireless Internet module 113 is a module for wireless Internet access, and may be built in or externally attached to the mobile terminal 100. The wireless Internet module 113 is configured to transmit and receive a wireless signal in a communication network according to wireless Internet technologies.

The short-range communication module 114 is for short-range communication, and includes Bluetooth ™, Radio Frequency Identification (RFID), Infrared Data Association (IrDA), Ultra Wideband (UWB) (Near Field Communication), Wi-Fi (Wireless-Fidelity), Wi-Fi Direct, and Wireless USB (Wireless Universal Serial Bus) technology.

Here, the other mobile terminal 100 may be a wearable device (e.g., a smartwatch, a smart glass, etc.) capable of interchanging data with the mobile terminal 100 according to the present invention (smart glass), HMD (head mounted display)). The short range communication module 114 may detect (or recognize) a wearable device capable of communicating with the mobile terminal 100 around the mobile terminal 100. [ If the detected wearable device is a device authenticated to communicate with the mobile terminal 100 according to the present invention, the control unit 180 may transmit at least a part of the data processed by the mobile terminal 100 to the short- 114 to the wearable device. Therefore, the user of the wearable device can use the data processed by the mobile terminal 100 through the wearable device.

The position information module 115 is a module for obtaining the position (or current position) of the mobile terminal, and a representative example thereof is a Global Positioning System (GPS) module or a Wireless Fidelity (WiFi) module. For example, when the mobile terminal utilizes the GPS module, it can acquire the position of the mobile terminal by using a signal transmitted from the GPS satellite. As another example, when the mobile terminal utilizes the Wi-Fi module, it can acquire the position of the mobile terminal based on information of a wireless access point (AP) that transmits or receives the wireless signal with the Wi-Fi module. Optionally, the location information module 115 may perform any of the other functions of the wireless communication unit 110 to obtain data relating to the location of the mobile terminal, in addition or alternatively. The location information module 115 is a module used to obtain the location (or current location) of the mobile terminal, and is not limited to a module that directly calculates or obtains the location of the mobile terminal.

Next, the input unit 120 is for inputting image information (or signal), audio information (or signal), data, or information input from a user. For inputting image information, Or a plurality of cameras 121 may be provided. The camera 121 processes image frames such as still images or moving images obtained by the image sensor in the video communication mode or the photographing mode. The processed image frame may be displayed on the display unit 151 or stored in the memory 170. [

The microphone 122 processes the external acoustic signal into electrical voice data. The processed voice data can be utilized variously according to a function (or a running application program) being executed in the mobile terminal 100. Meanwhile, the microphone 122 may be implemented with various noise reduction algorithms for eliminating noise generated in receiving an external sound signal.

The user input unit 123 is for receiving information from a user and when the information is inputted through the user input unit 123, the control unit 180 can control the operation of the mobile terminal 100 to correspond to the input information . The user input unit 123 may include a mechanical input means (or a mechanical key such as a button located on the front, rear or side of the mobile terminal 100, a dome switch, a jog wheel, Jog switches, etc.) and touch-type input means. For example, the touch-type input means may comprise a virtual key, a soft key or a visual key displayed on the touch screen through software processing, And a touch key disposed on the touch panel. Meanwhile, the virtual key or the visual key can be displayed on a touch screen having various forms, for example, a graphic, a text, an icon, a video, As shown in FIG.

Meanwhile, the sensing unit 140 senses at least one of information in the mobile terminal, surrounding environment information surrounding the mobile terminal, and user information, and generates a corresponding sensing signal. The control unit 180 may control the driving or operation of the mobile terminal 100 or may perform data processing, function or operation related to the application program installed in the mobile terminal 100 based on the sensing signal. Representative sensors among various sensors that may be included in the sensing unit 140 will be described in more detail.

First, the proximity sensor 141 refers to a sensor that detects the presence of an object approaching a predetermined detection surface, or the presence of an object in the vicinity of the detection surface, without mechanical contact by using electromagnetic force or infrared rays.

On the other hand, for convenience of explanation, the act of recognizing that the object is located on the touch screen in proximity with no object touching the touch screen is referred to as "proximity touch & The act of actually touching an object on the screen is called a "contact touch. &Quot; The position at which the object is closely touched on the touch screen means a position where the object corresponds to the touch screen vertically when the object is touched. The proximity sensor 141 can detect a proximity touch and a proximity touch pattern (e.g., a proximity touch distance, a proximity touch direction, a proximity touch speed, a proximity touch time, a proximity touch position, have. Meanwhile, the control unit 180 processes data (or information) corresponding to the proximity touch operation and the proximity touch pattern sensed through the proximity sensor 141 as described above, and further provides visual information corresponding to the processed data It can be output on the touch screen. Furthermore, the control unit 180 can control the mobile terminal 100 such that different operations or data (or information) are processed according to whether the touch to the same point on the touch screen is a proximity touch or a touch touch .

The touch sensor senses a touch (or touch input) applied to the touch screen (or the display unit 151) by using at least one of various touch methods such as a resistance film type, a capacitive type, an infrared type, an ultrasonic type, do.

For example, the touch sensor may be configured to convert a change in a pressure applied to a specific portion of the touch screen or a capacitance generated in a specific portion to an electrical input signal. The touch sensor may be configured to detect a position, an area, a pressure at the time of touch, a capacitance at the time of touch, and the like where a touch object touching the touch screen is touched on the touch sensor. Here, the touch object may be a finger, a touch pen, a stylus pen, a pointer, or the like as an object to which a touch is applied to the touch sensor.

Thus, when there is a touch input to the touch sensor, the corresponding signal (s) is sent to the touch controller. The touch controller processes the signal (s) and transmits the corresponding data to the controller 180. Thus, the control unit 180 can know which area of the display unit 151 is touched or the like. Here, the touch controller may be a separate component from the control unit 180, and may be the control unit 180 itself.

On the other hand, the control unit 180 may perform different controls or perform the same control according to the type of the touch object touching the touch screen (or a touch key provided on the touch screen). Whether to perform different controls or to perform the same control according to the type of the touch object may be determined according to the current state of the mobile terminal 100 or an application program being executed.

On the other hand, the touch sensors and the proximity sensors as described above can be used independently or in combination with each other to provide a short touch (long touch), a long touch (multi touch), a drag touch ), Flick touch, pinch-in touch, pinch-out touch, swipe touch, hovering touch, and the like. Touch can be sensed.

The ultrasonic sensor can recognize the position information of the object to be sensed by using ultrasonic waves. Meanwhile, the controller 180 can calculate the position of the wave generating source through the information sensed by the optical sensor and the plurality of ultrasonic sensors. The position of the wave source can be calculated using the fact that the light is much faster than the ultrasonic wave, that is, the time when the light reaches the optical sensor is much faster than the time the ultrasonic wave reaches the ultrasonic sensor. More specifically, the position of the wave generating source can be calculated using the time difference with the time when the ultrasonic wave reaches the reference signal.

The camera 121 includes at least one of a camera sensor (for example, a CCD, a CMOS, etc.), a photo sensor (or an image sensor), and a laser sensor.

The camera 121 and the laser sensor may be combined with each other to sense a touch of the sensing object with respect to the three-dimensional stereoscopic image. The photosensor can be laminated to the display element, which is adapted to scan the movement of the object to be detected proximate to the touch screen. More specifically, the photosensor mounts photo diodes and TRs (Transistors) in a row / column and scans the contents loaded on the photosensor using an electrical signal that varies according to the amount of light applied to the photo diode. That is, the photo sensor performs coordinate calculation of the object to be sensed according to the amount of change of light, and position information of the object to be sensed can be obtained through the calculation.

The display unit 151 displays (outputs) information processed by the mobile terminal 100. For example, the display unit 151 may display execution screen information of an application program driven by the mobile terminal 100 or UI (User Interface) and GUI (Graphic User Interface) information according to the execution screen information .

Also, the display unit 151 may be configured as a stereoscopic display unit for displaying a stereoscopic image.

The sound output unit 152 may output audio data received from the wireless communication unit 110 or stored in the memory 170 in a call signal reception mode, a call mode or a recording mode, a voice recognition mode, a broadcast reception mode, The sound output unit 152 also outputs sound signals related to functions (e.g., call signal reception sound, message reception sound, etc.) performed in the mobile terminal 100. [ The audio output unit 152 may include a receiver, a speaker, a buzzer, and the like.

The haptic module 153 generates various tactile effects that the user can feel. A typical example of the haptic effect generated by the haptic module 153 may be vibration. The intensity and pattern of the vibration generated in the haptic module 153 can be controlled by the user's selection or the setting of the control unit. For example, the haptic module 153 may synthesize and output different vibrations or sequentially output the vibrations.

In addition to vibration, the haptic module 153 may be configured to perform various functions such as a pin arrangement vertically moving with respect to the contact skin surface, a spraying force or suction force of the air through the injection port or the suction port, a touch on the skin surface, And various tactile effects such as an effect of reproducing a cold sensation using an endothermic or exothermic element can be generated.

The light output unit 154 outputs a signal for notifying the occurrence of an event using the light of the light source of the mobile terminal 100. Examples of events that occur in the mobile terminal 100 may include message reception, call signal reception, missed call, alarm, schedule notification, email reception, information reception through an application, and the like.

The interface unit 160 serves as a path for communication with all external devices connected to the mobile terminal 100. The interface unit 160 receives data from an external device or supplies power to each component in the mobile terminal 100 or transmits data in the mobile terminal 100 to an external device. For example, a port for connecting a device equipped with a wired / wireless headset port, an external charger port, a wired / wireless data port, a memory card port, an audio I / O port, a video I / O port, an earphone port, and the like may be included in the interface unit 160.

The memory 170 may store a program for the operation of the controller 180 and temporarily store input / output data (e.g., a phone book, a message, a still image, a moving picture, etc.). The memory 170 may store data related to vibration and sound of various patterns outputted when a touch is input on the touch screen.

The memory 170 may be a flash memory type, a hard disk type, a solid state disk type, an SDD type (Silicon Disk Drive type), a multimedia card micro type ), A card type memory (e.g., SD or XD memory), and a random access memory (RAM). The mobile terminal 100 may operate in association with a web storage that performs the storage function of the memory 170 on the Internet.

The power supply unit 190 receives external power and internal power under the control of the controller 180 and supplies power necessary for operation of the respective components. The power supply unit 190 includes a battery, the battery may be an internal battery configured to be chargeable, and may be detachably coupled to the terminal body for charging or the like. In addition, the power supply unit 190 may include a connection port, and the connection port may be configured as an example of an interface 160 through which an external charger for supplying power for charging the battery is electrically connected.

Hereinafter, a case where the display unit 151 is a light emitting diode (OLED) display device will be described with reference to FIG.

2 is a graph showing the current intensity of the PWM pulse driving the display panel in the normal mode and the outdoor visibility mode.

Referring to FIG. 2, in the normal mode, there is a limit to increase the pulse length due to time limitation. Therefore, in the case of a display that displays a gray scale by adjusting the pulse width (PWM) length, in order to improve the outdoor visibility, it is necessary to increase the intensity of the current in the outdoor visibility mode. However, if the current intensity is increased, the consumption power is increased and battery consumption is increased.

Accordingly, the present invention proposes a method of driving each data line of the display panel using current intensity of different magnitude in order to reduce power consumption in the outdoor visibility mode.

In one embodiment, the present invention drives a data line with a current intensity and a pulse width used in the normal mode when the outdoor visibility mode is low gray scale data, and drives the data line with the current intensity and pulse width in the outdoor visibility mode when the gray scale data is high gray scale data. Can be driven.

In another embodiment, the present invention provides a method of driving a low-gradation (high-current-use) data in an outdoor visibility mode with a current and a pulse in a normal mode So that the luminance (minimum brightness) difference is 2 to 3 gradations or less.

In another embodiment of the present invention, in order to reduce power consumption in the PWM driving method, current intensity can be driven differently for each data line according to image data.

In another embodiment, the present invention can adjust the number of gradation expressions in order to reduce power consumption in the low-gradation representation of the outdoor visibility mode in the PWM driving method.

FIG. 3 is a first embodiment of an image display apparatus to which a display unit 151 according to an embodiment of the present invention is applied. The image display device may be a light emitting diode (OLED) or an OLED display device.

3, the image display apparatus according to the first exemplary embodiment of the present invention includes a controller 210, a data driver 220, a scan driver 230, and a display panel 240. Referring to FIG.

The control unit 210 converts input image data (RGB data) according to a video mode (normal mode or outdoor visibility mode) and image gradation (low gradation or high gradation) and provides the data to the data driver 220. The control unit 210 is the same as the control unit 180 of FIG.

The data driver 220 receives the image data converted by the controller 210 and generates a data signal corresponding thereto. The data signal generated by the data driver 500a is supplied to the data lines D1- Dm and is transmitted to each pixel 110a of the display panel 240. [

The scan driver 400a generates scan signals, and the generated scan signals are sequentially supplied to the scan lines S1 to Sn.

The display panel 240 includes a plurality of pixels 110a connected to the scan lines S1 to Sn and the data lines D1 to Dm. Here, one pixel 110a may include at least two sub-pixels each having an organic light emitting diode and emitting light of different colors. The display panel 240 displays an image corresponding to power sources Vdd and Vss supplied from the outside, a scan signal of the scan driver 400a, and a data signal of the data driver 500a.

The control unit 210 may include an image processing unit 20, an image determination unit 21, a reset unit 22, and a frame memory 23.

The image processing unit 20 converts the image data (RGB data) according to the mode selection signal MDC to match the current intensity and pulse in the normal mode or the outdoor visibility mode. The image processor 20 outputs the current intensity and the pulse used in the normal mode when the gradation data is low gradation data in accordance with the gradation determination signal GS in the outdoor visibility mode and outputs the current intensity and pulse when the gradation data is high gradation data And a pulse. The mode selection signal MS may be automatically generated according to the intensity of external light through a user operation (touch or key input) or an optical sensor.

The image determination unit 21 determines whether the image data is low gray or high gray based on the maximum brightness MAXnormal that can be obtained in the normal mode and transmits the gray level determination signal GS to the image processing unit 400. [

The frame memory 22 receives image data from the image processing unit 20, stores the received image data, and transmits the stored image data to the data driver 220. The frame memory 22 stores image data in units of one frame.

The reset unit 23 outputs a reset signal to the frame memory 22 to delete the image data stored in the frame memory 22 and store the new image data in the frame memory 22 again. The reset signal is generated according to the gradation determination signal GS and the mode selection signal MS output to the image determination unit 21. [

4 is a block diagram of an image display apparatus to which a display unit 151 according to the second embodiment of the present invention is applied.

4, the image display apparatus according to the second embodiment of the present invention includes a controller 310, a data driver 320, a scan driver 330, and a display panel 340. The controller 310 And the operation of the data driver 320 are the same as in the first embodiment.

And outputs the mode selection signal MS and the gradation determination signal GS together with the input image data RGB data to the data driver 320. The data driver 320 receives the mode selection signal MS and the gradation determination signal GS, GS) and the image intensity data corresponding to the pulses in the normal mode or outdoor visibility mode to the display panel 340. [

A power saving method in the visibility mode operation in the LED display according to the embodiment of the present invention will be described.

5 is a flowchart illustrating a method of reducing power consumption in a visibility mode operation in an image display apparatus according to the present invention.

As shown in FIGS. 3 and 5, when the image data (RGB data) is input (S100), the controller 210 or 180 determines whether the image mode is the general mode or the outdoor visibility mode (S110 and S120). The image mode may be set by user input or may be automatically determined by comparing the intensity of the external light measured by the optical sensor with the intensity of predetermined light.

As a result of the determination, in the normal mode, the controller 210 converts the image data (RGB data) into image data having the current intensity and pulse width of the normal mode, and outputs the image data to the data driver 220 to drive the data lines D1 to Dm (S140).

On the other hand, in the outdoor visibility mode, the control unit 210 determines whether the image data (RGB data) is low gradation or high gradation (S130). The above criterion is based on the maximum brightness (high gray level of the normal mode) that can be obtained in the normal mode.

(RGB data) is converted into image data having current intensity and pulse width in the outdoor visibility mode and output to the data driver 220 to drive the data lines D1 to Dm in operation S150. The controller 210 converts the image data (RGB data) into image data having a current intensity and a pulse width of the normal mode, and outputs the image data to the data driver 220 to output the data lines D1 to Dm (S140).

Further, in the normal mode, the present invention can drive the data lines with different current intensities by converting the image data only in the outdoor visibility mode, without converting the image data.

Accordingly, the present invention is driven by current intensity and pulse width used in the normal mode when the low visibility mode is used in the outdoor visibility mode, and when the data line is driven by the current intensity and the pulse width in the outdoor visibility mode when high gradation data, The power consumption in the mode can be reduced.

FIGS. 6 and 7 illustrate the concept of driving a data line using two or more current intensities in the outdoor visibility mode.

As shown in FIG. 6, a combination of the current intensity and the pulse width used in the normal mode (normal gradation representation) can produce light intensity of some low gradations in the outdoor visibility mode in which the current intensity is increased. That is, the present invention can replace the low gray level of the outdoor visibility mode with the high gray level of the normal mode. At this time, as shown in FIG. 7, the control unit 210 compares whether the gradation of the image data is larger or smaller than the maximum brightness (maximum gradation) that can be obtained in the normal mode in the outdoor visibility mode, Or a high gradation.

As a result of the determination, the controller 210 uses the current intensity and pulse used in the normal mode for low gradation data in the outdoor visibility mode, and drives the data line using the current intensity and pulse in the outdoor visibility mode for high gradation data can do.

In addition, the controller 210 drives the display so that the difference between the maximum brightness (maximum brightness or high gradation) of the normal mode and the minimum brightness (minimum brightness or low gradation) of the outdoor visibility mode is 2 to 3 gradations or less, .

In general, the contrast ratio of the display is reduced to 100: 1 in the outdoor environment, and the discrimination power of the low gradation in the outdoor is remarkably deteriorated. This means that 255 gradations of the general display are not necessary in the outdoor.

Accordingly, the present invention proposes a method of reducing power consumption by reducing M gradations to M / N gradation representations (quantization) in the low gradation representation of the outdoor visibility mode.

8 is an embodiment for performing gray level quantization in a low gray level in the outdoor visibility mode.

8, the control unit 210 drives the data lines with the current intensity and the pulse width used in the normal mode from gradation (0 to 5) on the basis of the gradation (6) in the visibility mode, and thereafter Drives the data line with current intensity and pulse used in outdoor visibility mode. At this time, the control unit 210 automatically loads the value of the quantization coefficient N from a lock-up table (not shown) to reduce the number of gradations that should be displayed at low gradations in the outdoor visibility mode. Where N is the quantization coefficient determined by the brightness of the external light.

For example, when the quantization coefficient N = 2, the control unit 210 quantizes (converts) six gradations into three gradations (M / N = 2). That is, 6 gradation (0-5) data is converted into three gradation (0, 2, 4) data, and gradation (1, 3, 5) data which can not be represented is processed as a floor.

Therefore, the present invention can further reduce the power consumption by reducing M gradations to M / N gradation representation (quantization) in the low gradation representation of the outdoor visibility mode.

In general, LEDs can emit the same amount of light even if the current magnitude and pulse width are different, if the size of the current (current value) and the area of the turn-on interval produced by the pulse width are the same. In view of such a feature, the present invention is characterized in that one data (one frame) is represented by n different signals capable of emitting the same amount of light at a low gradation in the outdoor visibility mode, .

Fig. 9 is an example of driving pulses of one frame at different gradation levels in the outdoor visibility mode at different current intensities.

9, the image processing unit 20 in the control unit 210 changes the pulse of one frame to the first to third sub pulses (Frame 1/3, Frame 2/3, Frame 3/3) And the first to third sub-pulses are changed in height and width while maintaining the same area (pulse amplitude * pulse width), and the converted first to third sub-pulses are output as pulses of the one frame can do.

As described above, the present invention drives the current intensity and the pulse width used in the normal mode in low visibility mode and the current intensity and pulse width in the outdoor visibility mode when the high visibility data is used in the outdoor visibility mode Power consumption in the outdoor visibility mode can be reduced. In particular, when the low gradation of the visibility mode is expressed, M gradations are reduced to M / N gradation representations (quantization), thereby further reducing power consumption.

The present invention described above can be embodied as computer-readable codes on a medium on which a program is recorded. The computer readable medium includes all kinds of recording devices in which data that can be read by a computer system is stored. Examples of the computer readable medium include a hard disk drive (HDD), a solid state disk (SSD), a silicon disk drive (SDD), a ROM, a RAM, a CD-ROM, a magnetic tape, a floppy disk, , And may also be implemented in the form of a carrier wave (e.g., transmission over the Internet). Also, the computer may include a control unit 180 of the terminal. Accordingly, the above description should not be construed in a limiting sense in all respects and should be considered illustrative. The scope of the present invention should be determined by rational interpretation of the appended claims, and all changes within the scope of equivalents of the present invention are included in the scope of the present invention.

20: image processing unit 21:
22: Frame memory 23:
210, and 310, a controller 220, and 320,
230: scan driver 230, 330: scan driver
240, 340: pixel panel

Claims (18)

A display panel including a plurality of pixels connected to a scan line and a data line;
A scan driver driving a scan line;
A data driver for driving a delta line; And
And a controller for controlling the data driver so as to drive the data lines with different current intensities at the low gradation and the high gradation by discriminating the low gradation and high gradation of the image data in the outdoor visibility mode, . The display device according to claim 1, wherein the display panel
LED or an OLED display device. The apparatus of claim 1, wherein the control unit
And discriminates the image data as a low gradation and a high gradation based on a gradation giving maximum brightness in the normal mode. The apparatus of claim 1, wherein the control unit
Control the data lines to drive the low gray level data with current intensity and pulse width used in the normal mode,
And controls the high gray scale data to drive the data line with current intensity and pulse width in the outdoor visibility mode. The apparatus of claim 1, wherein the control unit
And the difference between the maximum brightness of the normal mode and the minimum brightness of the outdoor visibility mode is controlled to be 2 to 3 gradations or less when the low gradation data of the outdoor visibility mode is driven by the current of the normal mode and the pulse width. Device. The apparatus of claim 1, wherein the control unit
And converts M gradations into M / N gradations in the low gradation representation of the outdoor visibility mode. Here, N is a quantization coefficient determined according to the brightness of external light. 7. The apparatus of claim 6, wherein the control unit
And the gradation remaining unconverted among the M gradations is expressed as a truncation. The apparatus of claim 1, wherein the control unit
An image determination unit for determining whether the image data is a low gray level or a high gray level based on a maximum brightness that can be obtained in the normal mode and outputting a gray level determination signal;
An image processor for converting the image data according to a current intensity and a pulse of a normal mode or an outdoor visibility mode according to a mode selection signal and a gradation determination signal;
A frame memory for storing the image data converted by the image processor and transmitting the stored image data to the data driver; And
And a reset unit for outputting a reset signal to the frame memory according to the gray-level determination signal and the mode selection signal output from the image determination unit. 9. The method of claim 8,
Wherein the image is generated according to an input of a user or automatically generated according to the intensity of external light through an optical sensor. 9. The apparatus of claim 8, wherein the image processing unit
Wherein the image data is processed by replacing the low gradation of the outdoor visibility mode with the high gradation of the normal mode according to the mode selection signal and the gradation determination signal. Determining image mode when image data is input;
Determining gradation of the image data; And
And driving the data line with different current intensities for the determined low gray level and high gray level data when the image mode is the outdoor visibility mode. The method of claim 11, wherein the low gray level and high gray level of the image data are determined based on the gray level of the maximum brightness in the normal mode. 12. The method of claim 11, wherein driving the data line
Driving the data line with current intensity and pulse width using the low gray level data in the normal mode; And
And driving the data line with the current intensity and the pulse width of the outdoor visibility mode in the high gray level data. 14. The method of claim 13, wherein when the low tone data of the outdoor visibility mode is driven by the current of the normal mode and the pulse width, the difference between the maximum brightness of the normal mode and the minimum brightness of the outdoor visibility mode is controlled to be 2 to 3 gradations And the power consumption of the video display device is reduced. 14. The method of claim 13, further comprising: converting M gradations to M / N gradations in the low gradation representation of the outdoor visibility mode. Here, N is a quantization coefficient determined according to the brightness of external light. 16. The method according to claim 15, wherein the grayscale remaining unconverted among the M grayscales is discarded. 12. The method of claim 11, wherein driving the data line
Converting the image data according to a current intensity and a pulse of a normal mode or an outdoor visibility mode according to a mode selection signal and a gradation determination signal;
Storing the converted image data in a frame memory; And
And resetting the frame memory according to the gradation determination signal and the mode selection signal to output the stored image data to the data driver. 18. The method of claim 17, wherein the mode selection signal
Wherein the light source is generated according to a user's input or is automatically generated according to the intensity of external light through an optical sensor.

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