KR20060130860A - Combined pixel x-ray detector data read out control device - Google Patents

Abstract

A device for reading out the pixel combination of digital X-ray detector data is provided to supply a two gates type readout device of the digital X-ray image detector to effectively raise an amount of signal in each pixel. In a device for reading out the pixel combination of digital X-ray detector data, each gage line(411,412) forms a line pad on a side alternatively facing each other. A data transmission direction of each gate line(411,412) is alternatively progressed to both sides.

Description

Combined pixel X-ray detector data read out control device

1 is a structural diagram of a TFT panel 100 conventionally used

2 is a structural diagram of a TFT panel 100 in which a readout device is conventionally used.

3 is a block diagram of a pixel combination readout device of a digital x-ray image detector according to the present invention;

4 is a structural diagram of a large-area digital x-ray image detector formed by the practice of the present invention

5 is another structural diagram of a large area digital x-ray image detector according to the present invention.

6 is another structural diagram according to the embodiment of the present invention

* Explanation of symbols on main parts of the drawings *

100 TFT panel 102 data pad

103: gate pad 104: TFT array

201: charge amplifier 202: TFT cell

203: pixel electrode 204: capacitor

301: multiplexer 311, 312: data line

401, 402: gate driver 411, 412: gate line

501, 502: ADC 601, 602: Final video signal

According to the present invention, in the pixel combination readout device of the digital X-ray image detector, the gate lines are alternately formed to form line pads on opposite sides, whereby the data transfer directions of the respective gate lines are alternately performed on both sides. It relates to a pixel combination readout device of a digital x-ray image detector, characterized in that.

In general, a signal generated in each pixel of the substrate of the digital x-ray image detector is stored in a signal storage capacitor (Cst).

Hereinafter will be described with respect to the prior art method together with the drawings.

FIG. 1 is a structural diagram of a TFT panel 100 used in the related art. The data pad 102 is basically formed of a TFT array 104 and a horizontal horizontal gate line 411 and a vertical data line 311. And a configuration consisting of the gate pad 103.

FIG. 2 is a structural diagram of a TFT panel 100 having a readout device used in the related art, and includes a TFT panel 100 composed of a TFT cell 202, a pixel electrode 203, and a capacitor 204, and a TFT in such a panel. The gate driver 401 for selecting on-off, the multiplexer 301 for reading out the capacitor signal by turning on the TFT, and the final image signal 601 through the ADC 501 are shown.

The signal generated in each pixel of the substrate of the digital X-ray image detector is stored in a signal storage capacitor (Cst), and the signal stored for each pixel is switched by a gate driver as shown in FIG. 1. The data line is output through the data line, and is output through a charge amplifier positioned at the end of the data line.

Hereinafter, a real time radiography used for image processing, such as a video, among the conventional digital x-ray image detectors will be described.

In general, in the medical, scientific and industrial fields, an X-ray imaging apparatus using an invisible light such as X-ray is used. In a screen-film system, a film is a function of acquiring, displaying and storing a film. At the same time has the advantage of low cost and excellent portability.

On the other hand, the method of using a film causes a delay disorder in the diagnostic radiation and the film flow in the inside, and the material of the film is often unknown.

In addition, the copy quality is lower than the original film.

Digital Radiography (DR), which has been shown to overcome the disadvantages of this film method, optimizes each step by separating the acquisition, display, and storage of images, and thus can improve the diagnosis rate. The rate can be reduced to less than 1/10.

In addition, since it is a digital method, it is possible to obtain the same image without any deterioration in image quality when copying, and to solve the problem such as delay in reading due to the disturbance of film flow when connected to a network, and recently, the time taken for shooting and developing is remarkable. Systems that can be reduced to this situation are being developed.

The DR is divided into two operation modes, such as radiography for still images and video recording for real time.

However, in still images, a single image is obtained by high dose, indicating a high signal level, while in a movie, a typical 30 or 60 frames per second is obtained, and the dose itself is about 10-100 times lower than that of a still image. The size is also very low compared to still images.

Therefore, it is desirable to develop an X-ray detector substrate that can simultaneously use the two modes described above when manufacturing a detector substrate for DR.

However, such a detector substrate poses a problem with respect to pixel capacitance when designing the detector substrate.

In general still image capturing, a high X-ray dose results in a large intra-pixel signal, whereas in motion image capturing, a low dose X-ray is used, so the signal amount in a pixel is small.

However, in the past, the detector substrate designed to use two modes such as moving picture and still picture only takes the value of pixel capacitance as trade-off reading method (1 data per pixel).

However, in real time radiography, unlike a still image, a dose is required to see the patient's body for a long time. Therefore, a very small dose is used over a long period of time. Therefore, the image intensifier is used to display the small dose as an image for real-time viewing. Should be used.

This means that the amplification factor is typically thousands or more times higher, which means that an amplifier such as II is essential for imaging such small doses.In the digital X-ray detector developed so far, such a small signal such as the dynamic range of the image output is significantly lowered. This means that there are still a lot of problems in order to display the amount of images.

Hereinafter, the problem regarding the reading time of the substrate will be described.

The period t _on , which opens the TFT on any gate line, is given by: where m is the number of gate lines and f _F is the frame frequency.

t _on = (mf _F ) ^-1

If the frame frequency is 60 Hz and there are 480 gate lines, t _on will be 34.7 kHz.

This means that all signals for a line of pixels must be completely read out for 34.7 ms.

Even if a slight time delay occurs while the signal is read out, the amount of signal between the two lines causes cross talk and degrades the image quality.

Therefore, in order to solve the above problems, not only fast switching of a detector substrate such as TFT is required in real time radiography, but also a signal amount in each pixel is significantly lower than in a still image, and thus, another method for improving the problem is required.

An object of the present invention is to provide a pixel combination readout device of a digital x-ray image detector for realizing high-speed switching of a substrate in real time radiography.

In addition, another object of the present invention is to provide a pixel combination readout device of a digital x-ray image detector that effectively raises a signal amount in each pixel which is significantly lower than that of a still image.

That is, the present invention is to solve the above problems, but the conventional readout method is applied for still image shooting, but fast readout and signal by operating two gate lines and two data lines at the same time for video recording It is an object of the present invention to provide a pixel combination readout device for a digital x-ray image detector that performs amount amplification.

In order to achieve the above object, the present invention provides a pixel combination readout device of a digital X-ray image detector, wherein each gate line is alternated with each other to form line pads on opposite sides, so that the data transfer direction of each gate line is alternated to both sides. The technical combination of the pixel combination readout of the digital x-ray image detector, characterized in that proceeding.

Here, the gate lines are pixel combinations of the digital X-ray image detector, wherein two neighboring gate lines are simultaneously activated in a pair to obtain 1 pixel of information, so that 1 pixel information is output to both sides by two gate lines. It is preferable to become a lead-out apparatus.

The present invention also provides a pixel combination readout device for a large-area digital X-ray image detector in which two pixel combination readout devices of the digital X-ray image detector are formed by treating an unformed side that is a gate line and a data line with each other. It is a technical point.

And a pixel combination readout device for a digital x-ray image detector, comprising: a gate driver for simultaneously turning on two adjacent gate lines in a pair of gate lines of a digital x-ray image detector substrate; The two lines are composed of one set and connected orthogonally to the gate bus. When the gate signal generator sequentially turns on the information of the two gate lines, it simultaneously reads out the cell information located on the two gate lines. With data lines; Another technical gist is a pixel combination readout device of a digital x-ray image detector, which is configured.

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

3 is a block diagram of a pixel combination readout device of a digital x-ray image detector according to the present invention.

As shown in the figure, the present invention is a digital X-ray image detector consisting of a double-sided gate driver (401, 402) and a double-sided multiplexer (301, 302) and a double-sided gate pad 102 and data pad 103 The substrate (hereinafter, referred to as a substrate) and the gate lines 411 and 412 and data lines 311 and 312 and the charge amplifier 201 and ADCs 501 and 502 for reading data of the substrate. Has the basic structure of

In general, a signal generated in each pixel of the substrate of the digital x-ray image detector is stored in a signal storage capacitor (Cst).

As such, the signal stored for each pixel 30 is output to the data line 311 through the switching of the gate driver 401 as shown in FIG. 2, and the data line 311 (data). It is output through a charge amplifier 201 (charge amplifier) located at the end of the line.

Hereinafter, referring to FIG. 3, the pixel combination readout apparatus of the digital x-ray image detector according to the present invention may first include two gate lines 411 and 412 adjacent to odd and even lines among the gate drivers facing the digital x-ray image detector substrate. ) At the same time (on).

In the present invention, the gate driver is turned on and off at the same time, and the two gate lines are turned on at the same time. In general, a TFT substrate is used as a digital X-ray image detector. The loss of resolution is not so great.

The trigger method of the gate line is executed by adjusting a gate driver for generating an on-off control signal of the gate line.

In this step, when information of two gate lines is sequentially turned on, information of two gate line pixels is transferred to two opposite data lines on the gate line and applied to the charge amplifier stage.

The data transferred through the data line is amplified in the charge amplifier stage and represented as an image signal through the multiplexer and the ADC. Therefore, according to the settings of the gate driver and the multiplexer in the image signal from the present invention, one pixel signal by sequential driving of one pixel may be read, and up to four pixels may be sequentially read by one pixel value at a time. Implementations will have fast frame rates and readout speeds.

4 is a structural diagram of a large area digital x-ray image detector formed by the present invention.

In medical imaging, the capacitance of the data line is increased due to the panel and system configuration due to the large area, which causes noise and various problems.

In order to compensate for this drawback, the pixel vertical lead-out device of the digital X-ray image detector showing the lead-out structure through the pixel combination while reducing the capacitance of the data line by cutting the middle vertical axis on the TFT panel. .

5 is another structural diagram of a large-area digital X-ray image detector according to an exemplary embodiment of the present invention. Similarly to FIG. 4, in order to reduce the capacitance of the data line, the capacitance of the data line is reduced in half by using the horizontal axis rather than the vertical axis. And a device configuration diagram of a pixel combination readout device of a digital x-ray image detector showing a readout structure through pixel combination.

In the case of Figure 6 is another structural diagram according to the embodiment of the present invention in parallel with Figure 4 and 5, by cutting both the horizontal axis and the vertical axis to reduce the capacitance of the data line to a quarter and at the same time read-out structure through pixel combination Fig. 1 shows the device configuration of the pixel combination readout device of the digital x-ray image detector.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the embodiment of FIG. 3.

In the embodiment of FIG. 3, the first gate line 411 and the second gate line 412 are simultaneously turned on so that the amount of signals of two pixels in the first data line 311 is simultaneously along the data line 311. ) And the ADC 501, together with the second data line 312, a signal amount of two pixels is simultaneously output through the charge amplifier and the ADC 502 along the data line 312.

As a result, the output signal of two pixels per data line Dn and the output signal of four pixels due to two data lines are not only doubled or quadrupled compared to one pixel, but also increase the switching speed. Bring.

On the other hand, the gate drivers 401 and 402 for turning on and off the gate lines 411 and 412 can be easily experimented using, for example, FPGAs.

Field Programmable Gate Array (FPGA) is a collection of thousands of logics that can be programmed. An arbitrary logic circuit is designed and used by a user as intended by the user. When this is changed, the newly changed logic circuit can be inputted into the FPGA device to operate with the changed logic circuit, which is a variable logic device.

This indicates that two or several pixels can be bundled and used according to the user's purpose.

For example, if a precise medical picture is required, a method of increasing the resolution may be used. If a rough picture such as a search picture used at an airport is sufficient, a method of reducing the resolution and increasing sensitivity may be used.

What has been described above is only one embodiment for implementing the X-ray image detector according to the present invention, and the present invention is not limited to the above-described embodiment, and as claimed in the following claims, Without departing from the gist of the present invention, one of ordinary skill in the art will have the technical spirit of the present invention to the extent that various modifications can be made.

According to the present invention described above, there is an advantage that a pixel combination readout device of a digital x-ray image detector for realizing high-speed switching of a substrate in real time radiography is provided.

In addition, there is an advantage that a two-gate readout device of the digital x-ray image detector that effectively raises the signal amount in each pixel that is significantly lower than that of still images is provided.

That is, the present invention is to solve the above problems, but the conventional readout method is applied for still image shooting, but the fast readout and signal amplification by operating two or four gate lines at the same time for video recording There is an advantage that a pixel combination readout device of a digital x-ray image detector that executes the present invention is provided.

That is, in real time radiography, both gate drivers can be controlled to turn on two lines at the same time to read out the signal, and the data lines can also read two data lines at the same time and efficiently hold still images with the existing detector board. And the combination of the digital X-ray image detector pixel readout device which can selectively switch the video and improve the image quality through the fast readout and the increase of the signal amount when the video is acquired. have.

Claims (4)

A pixel combination readout device of a digital x-ray image detector, Each gate line alternates with each other to form line pads on opposite sides, whereby the data transfer direction of each gate line alternates to both sides to proceed. The method of claim 1, wherein the gate line 2. A pixel combination readout device of a digital x-ray image detector, wherein two neighboring gate lines are simultaneously activated in a pair to obtain information of one pixel, so that one pixel information is output to both sides by two gate lines. The pixel combination readout of the digital X-ray image detector constituting the large-area digital X-ray image is formed by forming two pixel combination readout devices of the digital x-ray image detector of claim 2, wherein the non-formed sides serving as the gate line and the data line are formed to face each other. Device. A pixel combination readout device of a digital x-ray image detector, A gate driver for simultaneously turning on two adjacent gate lines in a pair of gate lines of the digital X-ray image detector substrate; The two lines are composed of one set and connected orthogonally to the gate bus. When the gate signal generator sequentially turns on the information of the two gate lines, it simultaneously reads out the cell information located on the two gate lines. With data lines; And a pixel combination readout device of a digital x-ray image detector.

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