Display panel for processing biometrics using TFT photodetectors integrated thereon
A display panel includes a display pixel configured to irradiate light, an image sensor pixel included together with the display pixel in one unit pixel, including a thin film transistor (TFT) photodetector including an active layer formed of amorphous silicon or polycrystalline silicon on an amorphous transparent material, and configured to collect light reflected from a body located on the transparent material, and a processor configured to process biometrics along with positioning of the body according to the light reflected from the body.
1. A display panel comprising:
an amorphous transparent substrate;
a display pixel located on upper part of the amorphous transparent substrate and configured to irradiate light;
an infrared (IR) light source configured to irradiate IR light from one side surface of the amorphous transparent substrate to cause diffused reflection in the amorphous transparent substrate;
an image sensor pixel formed on the amorphous transparent substrate and configured to collect the light irradiated from the display pixel and the IR light source, reflected from a fingerprint of a body, and passed through the amorphous transparent substrate, wherein the image sensor pixel includes a thin film transistor (TFT) photodetector; and,
a backlight light source configured to irradiate backlight in a transmission direction of the amorphous transparent substrate through a space between adjacent TFT photodetectors;
wherein the image sensor pixel configured to collect the IR light diffusedly reflected from the fingerprint of the body that contacts the amorphous transparent substrate; and
a processor configured to process biometrics along with a position of the body according to the collected light,
wherein the image sensor pixel and the display pixel form one unit pixel, and
wherein the processor is configured to recognize a motion of a finger and a hand away from the surface of the amorphous transparent substrate and recognize the fingerprint when the backlight reflected from and transmitted to the finger enters cells of the TFT photodetector,
wherein the processor is configured to process biometrics from the hand spaced from the upper part of the amorphous transparent substrate by recognizing lines or vein of a palm of the hand using external light as natural light incident on the hand and the light irradiated from the display pixel located on the upper part of the amorphous transparent substrate,
wherein the amorphous transparent substrate is formed into a convex lens pattern at a position of the unit pixel,
wherein the convex lens pattern is configured to recognize on the motion of the finger and the hand apart from the amorphous transparent substrate and to recognize the lines or the vein of the palm of the hand, and
wherein the processor is configured to process biometrics from the finger or the hand spaced from the upper part of the amorphous transparent substrate, and then process the biometrics along with the position of the fingerprint that contacts the upper part of the amorphous transparent substrate by the IR light irradiated from the one side surface of the amorphous transparent substrate and then collected at the image sensor located on a lower part of the amorphous transparent substrate.
2. The display panel according to claim 1 , wherein the thin film transistor (TFT) photodetector comprises:
an active layer formed of amorphous silicon or polycrystalline silicon on the amorphous transparent substrate; and,
a metal protection layer formed on a boundary surface of the amorphous transparent substrate except for the active layer and configured to shield the light irradiated from the display pixel, and
wherein the light irradiated from the display pixel is transmitted into the amorphous transparent substrate through a space in which the metal protection layer is not formed, between adjacent TFT photodetectors.
3. The display panel according to claim 2 , wherein the unit pixel includes at least one transistor electrically coupled to the TFT photodetector and configured to generate a voltage output from photocurrent generated in the active layer.
4. The display panel according to claim 3 , wherein the active layer includes a material having a conductive property controllable by tunneling or an electric field.
5. The display panel according to claim 4 , wherein the active layer includes at least one of amorphous silicon or polycrystalline silicon.
6. The display panel according to claim 2 , wherein the TFT photodetector is formed in a structure in which when light is incident, electrons migrate into an N-type gate by tunneling from a P-type active layer to an oxide film, among charges of two PN areas excited with the oxide film in between, the electron migration changes a threshold voltage of a current channel between a source and a drain in correspondence with a change in a total amount of charge in the gate, photocurrent proportional to an intensity of incident light flowing in the active layer, and a voltage output is generated from the flowing photocurrent.
7. The display panel according to claim 2 , wherein the TFT photodetector comprises:
the amorphous transparent substrate;
a source formed of amorphous silicon or polycrystalline silicon on the amorphous transparent substrate;
a drain formed of amorphous silicon or polycrystalline silicon, opposite to the source on the amorphous transparent substrate;
the active layer formed between the source and the drain and including a current channel formed between the source and the drain;
an insulating oxide film formed on the source, the drain, and the active layer; and
a light receiver formed on the insulating oxide film, configured to absorb light, and insulated from the active layer by the insulating oxide film.
8. The display panel according to claim 7 , wherein in the TFT photodetector, when light is incident on the light receiver, electrons migrate by tunneling through the insulating oxide film between the light receiver and the active layer excited with the insulating oxide film in between, the electron migration changes an amount of charge in the light receiver, the changed amount of charge changes a threshold voltage of the current channel, and thus photocurrent flows in the current channel.
9. The display panel according to claim 2 , wherein the TFT photodetector is configured to use light generated from the display panel as a light source for the image sensor pixel.
10. The display panel according to claim 1 ,
wherein the image sensor pixel is configured to collect the backlight passed through the amorphous transparent substrate and then reflected back from the body.
11. The display panel according to claim 10 , wherein the processor is configured to process the biometrics along with the position of the body by the light generated from the backlight light source and then reflected from the body that contacts the amorphous transparent substrate.
12. The display panel according to claim 10 , wherein the processor is configured to process the biometrics along with the position of the body by the light generated from the backlight light source and then reflected from the body which does not contact the amorphous transparent substrate.
13. The display panel according to claim 1 , wherein the processor is configured to process the biometrics by identifying information about at least one of the lines, the vein, the fingerprint, or a face based on the light reflected from the body and comparing the identified information with pre-stored information.
14. A display panel comprising:
an amorphous transparent substrate;
a display pixel located on upper part of the amorphous transparent substrate and configured to irradiate light;
an infrared (IR) light source configured to irradiate IR light from one side surface of the amorphous transparent substrate to cause diffused reflection in the transparent substrate;
an image sensor pixel formed on the amorphous transparent substrate and configured to collect the light irradiated from the display pixel and the IR light source, reflected from a fingerprint of a body, and passed through the amorphous transparent substrate, wherein the image sensor pixel includes a thin film transistor (TFT) photodetector; and
a backlight light source configured to irradiate backlight in a transmission direction of the amorphous transparent substrate through a space between adjacent TFT photodetectors,
wherein the image sensor pixel is configured to collect the IR light diffusedly reflected from the fingerprint of the body that contacts the amorphous transparent substrate; and
a processor configured to process biometrics along with a position of the body according to the collected light,
wherein the image sensor pixel and the display pixel form one unit pixel,
wherein the image sensor pixel is formed in a structure in which when light is incident, electrons migrate into an N-type gate by tunneling from a P-type active layer to an oxide film, among charges of two PN areas excited with the oxide film in between, the electron migration changes a threshold voltage of a current channel between a source and a drain in correspondence with a change in a total amount of charge in the gate, photocurrent proportional to an intensity of incident light flows flowing in the active layer, and a voltage output is generated from the flowing photocurrent, and
wherein the processor is configured to recognize a motion of a finger and a hand away from the surface of the amorphous transparent substrate and recognize the fingerprint when the backlight reflected from and transmitted to the finger enters cells of the TFT photodetector,
wherein the processor is configured to process biometrics from the hand spaced from the upper part of the transparent substrate by recognized lines or vein of a palm of the hand using external light as natural light incident on the hand and the light irradiated from the display pixel located on the upper part of the amorphous transparent substrate,
wherein the amorphous transparent substrate is formed into a convex lens pattern at a position of the unit pixel,
wherein the convex lens pattern is configured to recognize on the motion of the finger and the hand apart from the amorphous transparent substrate and to recognize the lines or the vein of the palm of the hand, and
wherein the processor is configured to process biometrics from the finger or the hand spaced from the upper part of the amorphous transparent substrate, and then process the biometrics along with the position of the fingerprint that contacts the upper part of the amorphous transparent substrate by the IR light irradiated from the one side surface of the amorphous transparent substrate and then collected at the image sensor located on a lower part of the amorphous transparent substrate.