KR100848088B1 - device for processing image data of liquid crystal display and method therof - Google Patents

Abstract

The present invention relates to an apparatus and method for processing image data of a liquid crystal display device.

An image data processing apparatus for transmitting image data to a liquid crystal display device, comprising: a central processing unit for processing image data provided from an image signal source and transmitting the image data at a first frequency; And a buffer unit for buffering image data provided from the central processing unit and transmitting the image data to the liquid crystal display unit based on a second frequency according to a command provided from the central processing unit. Here, the second frequency is higher than the first frequency.

According to the present invention, image data is provided to the liquid crystal display device at a frequency faster and constant than the operating frequency regardless of the operating frequency of the central processing unit of the portable device, so that image data reproduction is regularly and regularly performed. The image can be continuously displayed without being cut off.

LCD, image signal processing, buffer

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a liquid crystal display (LCD)

1 is a conceptual diagram of a method of processing image data of a liquid crystal display device according to an embodiment of the present invention.

2 is a diagram showing a structure of an image data processing apparatus of a liquid crystal display according to an embodiment of the present invention.

3 is a flowchart showing an image data transmission operation of the liquid crystal display device according to the embodiment of the present invention.

4 is a diagram showing the timing of image data transmission operation of the liquid crystal display device according to the embodiment of the present invention.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display (LCD), and more particularly, to an apparatus and method for processing image data in a liquid crystal display device used in a portable device such as a mobile phone.

2. Description of the Related Art [0002] In recent years, a lightweight and thin display device such as a personal computer or a television has been required to be lighter and thinner. As a result, a flat display such as a liquid crystal display (LCD) Panel-type displays are being developed.

LCD is a display device that obtains a desired image signal by applying an electric field to a liquid crystal material having an anisotropic permittivity injected between two substrates and adjusting the intensity of the electric field to adjust the amount of light transmitted through the substrate. Such an LCD is typical of a flat panel type display that is easy to carry, and is also used in a monitor of a computer, a TV, or a portable device such as a cellular phone or a PDA (personal digital assistant).

A method for processing image data in a liquid crystal display device used in a portable device is largely divided into a method in which image data is processed by a CPU (central processing unit) of the portable device and a method in which image data is processed independently . ≪ / RTI >

The former method is also referred to as a CPU interface or a command interface in which image data is directly applied to the LCD module by the control of the CPU and the LCD module processes the image data in accordance with an instruction applied from the CPU. In the latter method, the image data is supplied to the LCD module through an image processor operated by the control of the CPU, and the LCD module processes the image data provided from the image processor according to an instruction provided from the CPU, Video interface or an RGB interface.                         

In this manner, in the conventional portable device, since the CPU controls not only the LCD module but also other modules for performing functions (such as data transmission / reception) inherent to the portable device, the CPU is less dedicated to controlling the LCD module, Accordingly, the transmission speed of the command transmitted to the LCD module for displaying the image data is slow.

Particularly, when image data is processed by the CPU interface method, since the image data is transferred to the LCD module depending on the CPU command, there is a problem that the operation is reproduced in a broken form without being continuously reproduced in the case of a moving image.

Also, in the CPU interface method, data of one screen is transmitted at an irregular rate when it is transmitted to the LCD module. That is, since the speed at which image data is transmitted to the LCD module is different when the portable device is in a call and when a call is not made, image data reproduction is irregular. For example, in a state where the CPU is transmitting image data to the LCD module to reproduce a moving image, when a call is generated, the CPU interrupts the LCD module control and performs call control. Accordingly, irregular image reproduction is performed such that data indicating the call state is displayed and the moving image is reproduced again after the moving image is reproduced.

SUMMARY OF THE INVENTION Accordingly, the present invention has been made to solve the above-mentioned problems occurring in the prior art, and it is an object of the present invention to provide a liquid crystal display device used in a portable device to reproduce image data at a regular speed.

Particularly, the moving image is continuously reproduced without being cut off.

According to an aspect of the present invention, there is provided an image data processing apparatus for transmitting image data to a liquid crystal display device, the image data processing apparatus comprising: A central processing unit for transmitting data at a first frequency; And a buffer unit for buffering image data provided from the central processing unit and transmitting the image data to the liquid crystal display device based on a second frequency in accordance with an instruction word provided from the central processing unit, Frequency.

Wherein the buffer unit comprises: a buffer memory for buffering the image data; And a memory controller for reading the image data buffered in the buffer memory according to a command provided from the central processor and transmitting the read image data to the liquid crystal display device according to the second frequency.

On the other hand, the central processing unit transmits the image data together with the start command for informing the image data transfer, and transmits a stop command indicating the completion of the transfer when the image data transfer is completed. The buffer unit receives the image data from the central processing unit When the command is transmitted, the image data transmission to the liquid crystal display starts. Also, the buffer unit outputs a busy signal to the central processing unit while the image data is transmitted to the liquid crystal display, and the central processing unit does not transmit image data to the buffer unit while the busy signal is being transmitted.                     

Such an image data processing apparatus of the liquid crystal display apparatus may be an apparatus for transmitting image data to a liquid crystal display apparatus used in a portable apparatus.

According to another aspect of the present invention, there is provided an image data processing method for transferring image data to a liquid crystal display device used in a portable device, the method comprising the steps of: Transmitting; Buffering the transmitted image data; And transmitting the buffered image data to the liquid crystal display according to a second frequency when the transmission of the image data is completed, wherein the second frequency is higher than the first frequency.

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

Fig. 1 shows an image processing concept of a liquid crystal display device according to an embodiment of the present invention.

1, in the embodiment of the present invention, when image data is processed by a CPU interface method in a liquid crystal display device used in a mobile device such as a cellular phone or a PDA, image data and a command After receiving the buffer unit, the buffer unit supplies image data and commands to the LCD module at a transmission rate (second transmission frequency) set for regularly reproducing the image data irrespective of the image data transmission rate (first transmission frequency) of the CPU So that image data is displayed.

Where the first transmission frequency has a value of "xx KHz ", and the second transmission frequency has a value of" xxMHz ", for example 4.5 MHz, which is significantly faster than the first transmission frequency. Here, the first transmission frequency is variable, and the second transmission frequency has a fixed value set for continuously reproducing image data such as moving images irrespective of the first transmission frequency.

Thus, by providing the image data provided from the CPU to the LCD module in accordance with the set frequency, the moving image or the like can be continuously and accurately reproduced even in a portable device or the like.

Fig. 2 shows in detail the structure of an image data processing apparatus of a liquid crystal display device that processes image data on the basis of this concept.

2, the image data processing apparatus according to the embodiment of the present invention includes a CPU 2, a buffer unit 3, and a clock generating unit 4. The CPU 2 receives image data from the image signal source 1, (LCD) device 4, which is connected to the liquid crystal display device.

The CPU 2 outputs the image data provided from the image signal source 1 together with the instruction word at the first transmission frequency so as to reproduce the image data, and controls the data transmission / reception module (not shown) of the portable device So that a call with another portable device is made.

The LCD module 4 includes a timing controller 41, a gate driver 43, a data driver 42 and a liquid crystal panel 44. The LCD module 4 according to the present embodiment is a STN (super twisted nematic) liquid crystal display device, but is not limited thereto.

The liquid crystal panel 44 has a structure in which a liquid crystal layer is formed between a segment electrode and a common electrode, and a pixel electrode is defined by an electrode terminal where a segment electrode and a common electrode overlap.

The data driver 42 supplies a signal voltage to the segment electrodes constituting each pixel. That is, the data driver 42 stores the digital data which is transmitted from the timing controller 41, which will be described later, in the shift register in the data driver, and when a signal (LOAD signal) And transmits the selected voltage to the liquid crystal panel 44. [0050]

The gate driver 43 sequentially supplies a scan signal to the common electrode so that a specific voltage from the data driver 42 can be applied to the pixel.

The timing controller 41 generates a digital signal for driving the data driver 42 and the gate driver 43. Specifically, the timing controller 41 sequentially shifts image data for each segment electrode according to a predetermined clock rate, And supplies it to the driving unit 42. When all the image data are provided, the load signal LOAD is generated and output. The gate driver 43 supplies the gate clock signal and the frame start signal to the gate driver 43 so that the gate driver 43 can sequentially scan the common electrode of the liquid crystal panel 44 while being synchronized with the data driver 42.

On the other hand, the CPU 2 buffers the image data and the instruction provided in accordance with the first frequency and provides the buffered image data according to the second frequency higher than the first frequency to the LCD module 4, The buffer unit 3 includes a buffer memory 31 and a memory control unit 32.

The image data provided from the CPU 2 is stored in the buffer memory 31. The memory controller 32 controls the image data stored in the buffer memory 31 in accordance with a command provided from the CPU 2, And provides it to the LCD module 4.

The clock generating unit 5 generates a main clock signal for operation of the buffer unit 3 and provides the main clock signal to the CPU 2 and the buffer unit 3, respectively.

Next, the image data processing operation of the liquid crystal display device according to the embodiment of the present invention having such a structure will be described in more detail.

3 is a flowchart showing an image data transfer operation according to the embodiment of the present invention.

When the portable device is initially powered on, the LCD module 4 operates in the display-off mode. After the initial screen data provided from the CPU 2 is transmitted, the LCD module 4 operates in the display- Screen data is displayed (S100 to S140).

For example, in a state in which initial screen data indicating dates, times, etc. are being displayed, image data transmitted from another portable device or downloaded through a wireless Internet, or image data stored in an internal memory of the portable device, The CPU 2 supplies the image data provided from the image signal source 1 to the buffer unit 3 so as to display the image data (S150 to S170).

Specifically, the CPU 2 provides an instruction word instructing display of the image data together with the image data to the buffer unit 3, and transmits the image data according to the first frequency. The first frequency is variable and may vary depending on whether the portable device is in a call or an external signal input through a keypad of the portable device.

The buffer unit 3 buffers the image data provided from the CPU 2 in the buffer memory 31. The memory control unit 32 of the buffer unit 3 stores the image data supplied from the CPU 2 Reads the image data stored in the buffer memory 31 based on a start command and a stop command to be provided to the LCD module 4, and provides the image data to the LCD module 5.

Fig. 4 shows a timing chart of the image data processing operation according to the embodiment of the present invention.

4, the memory control unit 32 of the buffer unit 3 prepares to receive image data according to a start instruction word provided from the CPU 2, and thereafter stores image data supplied from the CPU 2 in a buffer The buffer unit 3 buffers in the memory 31 and the buffer unit 3 starts transmitting image data to the LCD module 4 when a stop instruction indicating the end of image data transfer is transmitted from the CPU 2. [

That is, the memory control unit 32 divides the main clock signal inputted from the clock generating unit 5 to generate a second transmission frequency (for example, 4.5 MHz), and outputs the generated second clock signal to the buffer memory 31 And transmits the read image data to the LCD module 4. [ At this time, the memory control unit 32 of the buffer unit 3 outputs a busy signal Busy to the CPU 2 to inform that the image data is being transferred to the LCD module 4 at present. Therefore, the CPU 2 does not transfer the image data to the buffer unit 3 while the busy signal is outputted.                     

The buffer unit 3 provides image data to the LCD module 4 at a second transmission frequency that is significantly higher than the first transmission frequency while the busy signal is generated as described above, (41) supplies the applied image data to the data driver (42). The data driver 42 converts the image data into the corresponding gradation voltages in synchronization with the data clock signal CLK3 and then applies the gradation voltages to the segment electrodes of the liquid crystal panel 44 in accordance with the applied load signal. Synchronously applies a common voltage, which is a scanning signal, to the common electrode of the liquid crystal panel 44 in synchronization with the gate clock signal output from the timing control unit 41. [

Therefore, the alignment state of the liquid crystal is changed according to the potential difference between the common electrode and the segment electrode applied with the common voltage, and accordingly, the light transmission amount is changed, and a desired image is displayed.

As described above, in the embodiment of the present invention, image data provided at a slow and irregular rate provided from the CPU is supplied to the LCD module at a fast and regular speed, so that even if the image is moving, .

The image data from the CPU may be transmitted in units of one frame. In the case of displaying a moving image, only the image data corresponding to the portion where the image data is changed compared with the previous frame among the image data of one frame may be transmitted. Accordingly, image information indicating whether the transmitted image data corresponds to one frame or one frame is provided to the buffer unit. The buffer unit provides image data to the LCD module based on such image information, So that only the portion having the image data change is displayed.

The present invention can be variously modified and practiced without departing from the scope of the following claims.

As described above, according to the present invention, when image data is transmitted to a liquid crystal display device used in a portable device, the image data is transmitted to the LCD By providing them as modules, image data reproduction can be performed regularly and regularly.

In addition, even in the case of a moving image, the image can be continuously displayed without being cut off.

Claims (6)

An image data processing apparatus for transferring image data to a liquid crystal display device, A central processing unit for processing image data provided from an image signal source and transmitting the processed image data at a first frequency; A buffer unit for buffering image data provided from the central processing unit and transmitting the image data to the liquid crystal display device at a second frequency in accordance with an instruction word provided from the central processing unit; / RTI > And the second frequency is higher than the first frequency. The method according to claim 1, The buffer unit includes: A buffer memory for buffering the image data; A memory controller for reading the image data buffered in the buffer memory according to an instruction word provided from the central processor and transmitting the read image data to the liquid crystal display device according to a second frequency, And an image processing unit for processing the image data. The method according to claim 1, The central processing unit transmits the image data together with the start command for informing of the image data transmission, the stop command indicating the completion of the transmission when the image data transmission is completed, Wherein said buffer unit starts transmission of image data to said liquid crystal display device when a stop instruction indicating completion of transmission of image data is transmitted from said central processing unit. The method according to claim 1, Wherein the image data processing device of the liquid crystal display device is a device for transferring image data to a liquid crystal display device used in a portable device. The method according to claim 1, Wherein the buffer unit outputs a busy signal to the central processing unit while the image data is transmitted to the liquid crystal display, and the central processing unit does not transmit the image data to the buffer unit while the busy signal is being transmitted. Device. An image data processing method for transmitting image data to a liquid crystal display device used in a portable device, Transmitting the image data provided from an image signal source at a first frequency; Buffering the transmitted image data; And transmitting the buffered image data to the liquid crystal display according to a second frequency when the transmission of the image data is completed Wherein the second frequency is higher than the first frequency, and the second frequency is higher than the first frequency.

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