Image sensor and method for improving readout speed
地域：
Gyeonggi-do
摘要
The present invention provides an image sensor comprising: pixels arranged along a plurality of row lines and column lines in a matrix form; a scan driving unit for selecting the row lines in the unit of n lines in a binning mode; and a read circuit unit for outputting n*m binning signals generated by sampling n*1 signals output in every column line according to the selection of the row lines and averaging the sampled n*1 signals in the unit of m neighboring column lines, wherein each of n and m is a natural number larger than or equal to 2.
說(shuō)明書
This application is a National Stage Patent Application of PCT International Patent Application No. PCT/KR2014/003778 (filed on Apr. 29, 2014) under 35 U.S.C. § 371, which claims priority to Korean Patent Application No. 10-2013-0049429 (filed on May 2, 2013), the teachings of which are incorporated herein in their entireties by reference.
Field of the Invention
The present invention relates to an image sensor, and more particularly, to an image sensor and a method for driving the same capable of improving a readout speed in a binning mode.
Description of the Related Art
An image sensor is a device for detecting optical image signals from the outside and converting the optical image signals into electric signals and has been widely used by being installed in various electronic equipments.
The image sensor has light detecting elements, i.e., pixels arranged along row lines and column lines in a matrix form, and each pixel includes a photodiode for converting incident lights into electrical signals.
A pixel of the image sensor has a small size, and there is a limit to the amount of light which the photodiode can receive. To improve this, the image sensor driven in binning mode has been used.
In a normal mode, an image is formed by using the electric signals generated in each pixel, but in the binning mode, an image is formed by summing electrical signals of neighboring pixels.
權(quán)利要求
What is claimed is:1. An image sensor, comprising:a plurality of pixels arranged in a matrix form along a plurality of x row lines and m column lines, wherein the x and the m are integer numbers equal to or greater than 1; a scan driver configured to sequentially select the row lines, wherein the scan driver is configured to simultaneously select n row lines at each selection sequence in a binning mode, wherein the n is an integer number equal to or greater than 2; and a readout circuit configured to, at each selection sequence in the binning mode, simultaneously read n signals from pixels arranged at the selected n row lines and each one of the m column lines, to generate sampled signals of each column line by sampling the n signals of one column line, to average the sampled n signals of the m column lines, and to output the averaged signals as binning signals, the readout circuit further including first sampling circuits and second sampling circuits, wherein either one of the first sampling circuits and the second sampling circuits sample the n signals output from each of the m column lines, while the other one of the first sampling circuits and second sampling circuits output the binning signals. 2. The image sensor of claim 1 , wherein the readout circuit includes:connecting switches configured to turn on/off respective connections of m number of the first sampling circuits and the second sampling circuits. 3. The image sensor of claim 2 , wherein each of the first sampling circuits and the second sampling circuits includes:a first switch configured to turn on/off input of the n signals; a capacitor configured to store the n signals and to store the binning signals when the connecting switch is in turns on state; and a second switch configured to turn on/off output of the binning signals. 4. The image sensor of claim 1 , wherein the readout circuit is configured to sequentially output the binning signals with the m number of column line basis. 5. A method of driving an image sensor including a plurality of pixels arranged in a matrix form along a plurality of x row lines and m column lines, wherein the x and the m are integer numbers equal to or greater than 1, comprising:sequentially selecting the row lines by simultaneously selecting n row lines at each selection sequence in a binning mode, wherein the n is an integer number equal to or greater than 2; and at each selection sequence in the binning mode, simultaneously reading n signals from pixels arranged at the selected n row lines and each one of the m column lines, sampling the read_n signals from each of the m column lines, and outputting binning signals by averaging the n signals of the m column lines with a readout circuit, wherein the sampling the read n signals and the outputting binning signals comprises: sampling by either one of first sampling circuits and second sampling circuits the n signals output from each of the m column lines, while the other one of the first sampling circuits and second sampling circuits output the binning signals. 6. The method of claim 5 , further comprising:sampling, by turns, the n signals output from each of the m column lines, and outputting, by turns, the binning signals with first sampling circuits and second sampling circuits included in-the readout circuit, wherein the binning signals are formed by connecting m number of the first sampling circuits and the second sampling circuits. 7. The method of claim 6 , wherein each of the first sampling circuits and the second sampling circuits includes:a first switch configured to turn on/off input of the n signals; a capacitor configured to store the n signals and to store the binning_signals when the connecting switch is in a turn-on state; and a second switch configured to turn on/off output of the binning signals. 8. The method of claim 5 , wherein the readout circuit is configured to sequentially output the binning signals of the m number of column lines. 9. An image sensor, comprising:a plurality of pixels arranged in a matrix form along a plurality of x row lines and m column lines, wherein the x and the m are integer numbers equal to or greater than 1; a plurality of scan lines respectfully extended from the x row lines; a plurality of readout lines respectfully extended from the m column lines; a scan driver connected to the scan lines and configured to sequentially select the row lines, wherein the scan driver is configured to simultaneously select n row lines at each selection sequence in a binning mode or to select one row line at each selection sequence in a normal mode; and a readout circuit connected to the readout lines and configured to, in the binning mode, simultaneously read n signals from each of the readout lines at each selection sequence, to sample the n signals, to average the n signals of the m column lines, and to output binning signals, or, in the normal mode, to sample and output signals from each of the readout lines sequentially, wherein the readout circuit includes: first sampling circuits and second sampling circuits coupled in parallel and wherein either one of the first sampling circuits and the second sampling circuits sample the n signals output from each of the m column lines, while the other one of the first sampling circuits and second sampling circuits output the binning signals; and connecting switches configured to turn on/off respective connections of m number of the first sampling circuits and the second sampling circuits in accordance with averaging control signals, wherein each of the first sampling circuits and the second sampling circuits includes a first switch configured to turn on/off input of the n signals according to sampling control signals, a metal oxide semiconductor (MOS) capacitor configured to store the n signals and to store the binning signals when the connecting switch is in a turn-on state, and a second switch configured to turn on/off output of binning signals.
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