Image sensor array and liquid crystal display with sensor elements

#The present invention relates to an image sensor array with photosensing devices and the driving method thereof, and more particularly to an a-Si TFT-LCD.

#An a-Si TFT sensor array is operated with the photosensitive characteristic of the amorphous silicon thin film transistors. There exist two kinds of the a-Si TFT sensor arrays: a charge-type sensor array and a current-type sensor array.

#Please refer to FIG. 1, which is a circuit diagram showing a sensor element of a charge-type sensor array according to the prior art. The sensor element 1 includes a photosensing device 10, a storage capacitor 11 and a readout switch device 12. The photosensing device 10 generates a photocurrent in response to received light. The gate electrode 101 and the source electrode 103 of the photosensing device 10 are both coupled to a bias voltage 13 which is usually connected to common voltage. The source and drain electrodes 103, 102 of the photosensing device 10 are also coupled to the storage capacitor 11 which is discharged when the photosensing device 10 is exposed to light. The storage capacitor 11 is coupled to the source electrode 121 of the readout switch device 12, too. The charge on the storage capacitor 11 is read out periodically through the readout switch device 12 and a readout line 14. As shown, the gate electrode 122 of the readout switch device 12 is coupled to a switch line 15 to enable the readout switch device 12 switching. The drain electrode 123 of the readout switch device 12 is coupled to the readout line 14 to readout the charge.

#FIG. 1 is a circuit diagram showing a sensor element of a charge-type sensor array according to the prior art;

#FIG. 2 is a circuit diagram showing a sensor element of a current-type sensor array according to the prior art;

#FIG. 3 is a cross-sectional view showing a TFT-LCD embedded by sensor elements according to the prior art;

#The present invention will now be described more specifically with reference to the following embodiments. It is to be noted that the following descriptions of preferred embodiments of this invention are presented herein for the purposes of illustration and description only; it is not intended to be exhaustive or to be limited to the precise form disclosed.

#Please refer to FIG. 7 (A), which is a partial circuit diagram showing an image sensor array according to the present invention. As shown, the image sensor array 7 includes m readout lines RO1-m, n switch lines SW1-n and a plurality of sensor elements. In this embodiment, the image sensor array 7 comprises the current-type sensor elements as shown in FIG. 2, but it can also be replaced by the charge-type sensor elements as shown in FIG. 1. The m readout lines RO1-m are parallel to one another to read out photocurrents from the sensor elements. The n switch lines SW1-n are parallel to one another and perpendicular to the m readout lines RO1-m so that m×n positions are defined by m×n intersections. For example, the sensor element on the position defined by the readout line RO1 and the switch line SW1 is symbolized by SE11.

#In this embodiment, the switch line SW1 is connected the corresponded sensor elements SE11 and SE12, but there are no sensor element arranged on the position defined by the readout lines RO3, 4 and the switch line SW1, which are called un-sensing areas US13 and US14. The position of sensor elements disposed on the switch line SW2 are different from those on the switch line SW1. There are no sensor elements disposed on the position defined by the readout lines RO2 and the switch line SW2, the un-sensing areas U21 and U22 are arranged on the positions defined by the switch line SW2 and the readout lines RO1-2. The switch line SW2 is connected to the sensor elements SE23 and SE24. Furthermore, the arrangement of the sensor elements of the odd switch lines is the same as that of the switch line SW1, and the arrangement of the sensor elements of the even switch lines is the same as that of the switch line SW2.