Fingerprint sensor and interface
A fingerprint sensor interface that connects to a standard camera interface and minimizes input and output signals to reduce sensor die area and cost. The sensor can connect to a standard camera interface of a cellular telephone baseband processor or other device intended to receive signals from a camera. Input and output pad are arranged on a single edge of the die. Circuitry between the pads and the sensor active array creates clearance from the array to the bond wires connected to the pads.
1. A fingerprint sensor integrated circuit, rectangular in shape with a long dimension and short dimension, comprising:
an electrical interface for communicating image data comprising:
a pixel clock signal for defining data bit intervals;
pixel data signal for transmitting serial image data;
a synchronization signal for defining lines and frames of image data;
wherein pixel data from the sensor is serialized and transmitted on the pixel data signal and wherein the fingerprint sensor connects to a standard camera interface;
an active sensor area with a long axis and a short axis, the long axis oriented parallel to the long dimension of the integrated circuit;
electrostatic discharge protection arranged parallel to the sensor long axis adjacent to the upper and lower edges of the long axis of the sensor area;
at least one column of input and output pads arranged along one edge of the short dimension;
circuitry positioned in between the pads and the sensor area adjacent to one edge of the short axis of the sensor area; and
wherein the width of the circuitry separates the pads from the sensor and creates a clearance distance.
2. The fingerprint sensor of claim 1 wherein the standard camera interface is on a cellular telephone baseband processor.
3. The fingerprint sensor of claim 1 wherein the standard camera interface is on a laptop computer.
4. The fingerprint sensor of claim 1 connected to the camera interface simultaneously with a camera.
5. The fingerprint sensor of claim 4 wherein the synchronization signal output from the sensor is connected to the camera interface through a resistor.
6. The fingerprint sensor of claim 4 wherein the synchronization signal output from the sensor is connected to the camera interface through a diode.
7. The fingerprint sensor of claim 1 wherein the pixel data is binarized within the fingerprint sensor and single-bit pixel data values are transmitted.