CN111244196B - Light-sensitive thin film transistor, display panel and display device - Google Patents
Light-sensitive thin film transistor, display panel and display device Download PDFInfo
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- CN111244196B CN111244196B CN202010049350.2A CN202010049350A CN111244196B CN 111244196 B CN111244196 B CN 111244196B CN 202010049350 A CN202010049350 A CN 202010049350A CN 111244196 B CN111244196 B CN 111244196B
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L31/08—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof in which radiation controls flow of current through the device, e.g. photoresistors
- H01L31/10—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof in which radiation controls flow of current through the device, e.g. photoresistors characterised by at least one potential-jump barrier or surface barrier, e.g. phototransistors
- H01L31/101—Devices sensitive to infrared, visible or ultraviolet radiation
- H01L31/112—Devices sensitive to infrared, visible or ultraviolet radiation characterised by field-effect operation, e.g. junction field-effect phototransistor
- H01L31/113—Devices sensitive to infrared, visible or ultraviolet radiation characterised by field-effect operation, e.g. junction field-effect phototransistor being of the conductor-insulator-semiconductor type, e.g. metal-insulator-semiconductor field-effect transistor
- H01L31/1136—Devices sensitive to infrared, visible or ultraviolet radiation characterised by field-effect operation, e.g. junction field-effect phototransistor being of the conductor-insulator-semiconductor type, e.g. metal-insulator-semiconductor field-effect transistor the device being a metal-insulator-semiconductor field-effect transistor
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L31/02—Details
- H01L31/0224—Electrodes
- H01L31/022408—Electrodes for devices characterised by at least one potential jump barrier or surface barrier
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L31/0248—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by their semiconductor bodies
- H01L31/0352—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by their semiconductor bodies characterised by their shape or by the shapes, relative sizes or disposition of the semiconductor regions
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- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
- H10K59/00—Integrated devices, or assemblies of multiple devices, comprising at least one organic light-emitting element covered by group H10K50/00
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- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
- H10K59/00—Integrated devices, or assemblies of multiple devices, comprising at least one organic light-emitting element covered by group H10K50/00
- H10K59/10—OLED displays
- H10K59/12—Active-matrix OLED [AMOLED] displays
Abstract
The embodiment of the invention discloses a light-sensitive thin film transistor, a display panel and a display device, wherein the light-sensitive thin film transistor comprises an active layer, the active layer comprises a first doping area and second doping areas positioned on two sides of the first doping area, the doping concentration of the second doping areas is greater than that of the first doping area, and the two second doping areas correspondingly form a source electrode and a drain electrode of the light-sensitive thin film transistor; the grid is located above the active layer, the area of the grid is smaller than that of the first doping area, the vertical projection of the first doping area covers the vertical projection of the grid, and the part, which is not shielded by the grid, of the first doping area is used for adjusting photo-generated current generated by the photo-sensing thin film transistor according to light reflected to the first doping area through the touch main body. The technical scheme provided by the embodiment of the invention is beneficial to realizing fingerprint identification in a large-area range or even a full-screen range of the display panel.
Description
Technical Field
The embodiment of the invention relates to the technical field of display, in particular to a light-sensitive thin film transistor, a display panel and a display device.
Background
The fingerprint identification means that the identification is carried out by comparing the minutiae characteristic points of different fingerprints, the fingerprints of each person are different, namely the fingerprints of the same person have obvious difference, and therefore the fingerprints can be used for the identification. The realization mode of fingerprint identification mainly has capacitanc, optics formula and ultrasonic wave formula three kinds, and the capacitanc generally has the very little problem of electric capacity semaphore to the condition that the distance between finger and the sensor electrode is more than 300um, can't carry out reading of signal, and the ultrasonic wave formula still has technical safety problem because the medium of display area is too much, and optics fingerprint identification is the fingerprint identification mode of better integration in the display screen.
The existing optical fingerprint identification is generally fixed-position fingerprint identification, namely, a fingerprint identification sensor is fixed at a certain position in a screen body, along with the development of a fingerprint identification technology, how to realize large-area or even full-screen fingerprint identification becomes the development trend of future fingerprint identification, and the existing fingerprint identification requirement has no good solution.
Disclosure of Invention
The embodiment of the invention provides a light-sensing thin film transistor, a display panel and a display device, which are beneficial to realizing fingerprint identification in a large-area range or even a full-screen range of the display panel.
In order to realize the technical problem, the invention adopts the following technical scheme:
in a first aspect, an embodiment of the present invention provides a light-sensing thin film transistor, including:
the active layer comprises a first doping area and second doping areas positioned on two sides of the first doping area, the doping concentration of the second doping areas is greater than that of the first doping area, and the two second doping areas correspondingly form a source electrode and a drain electrode of the photosensitive thin film transistor;
the grid electrode is located above the active layer, the area of the grid electrode is smaller than that of the first doping area, the vertical projection of the first doping area covers the vertical projection of the grid electrode, and the part, which is not shielded by the grid electrode, of the first doping area is used for adjusting photo-generated current generated by the photo-sensing thin film transistor according to light reflected to the first doping area through the touch main body.
Further, the ratio of the area of the portion, which is not covered by the gate, of the first doped region to the area of the portion, which is opposite to the gate, of the first doped region is greater than or equal to 1.2.
In a second aspect, embodiments of the present invention further provide a display panel, including a plurality of light-sensitive thin film transistors as described in the first aspect.
Further, at least part of the display area of the display panel is provided with the light-sensitive thin film transistor;
preferably, the entire display area of the display panel is provided with the light-sensitive thin film transistor.
Further, the display panel further includes:
the light sensing thin film transistor is positioned on the substrate, the light emitting structures are positioned on one side, far away from the substrate, of the light sensing thin film transistor, the light emitting structures provide light sources for the light sensing thin film transistor, and the light sensing thin film transistor is used for adjusting light generation current generated by the light sensing thin film transistor according to light rays emitted by the light emitting structures and reflected to the light sensing thin film transistor through the touch main body;
preferably, when the light-sensitive thin film transistor performs fingerprint identification, at least the green light-emitting structure provides a light source for the light-sensitive thin film transistor.
Furthermore, at least two light-emitting structures with different light-emitting colors form a pixel unit, and one light-sensitive thin film transistor is arranged corresponding to at least one pixel unit;
preferably, the light-sensing thin film transistors are arranged in one-to-one correspondence with the pixel units.
Further, the display panel further includes:
and the light sensing thin film transistors and the pixel thin film transistors are manufactured in the same layer.
Furthermore, a lower electrode arranged on one side of the light-emitting structure, which is close to the substrate, exposes at least a part of the first doped region which is not shielded by the corresponding gate;
preferably, the lower electrode disposed on a side of the light emitting structure adjacent to the substrate does not block a portion of the first doped region that is not blocked by the corresponding gate.
Further, when the light-sensitive thin film transistors perform fingerprint identification, the potential differences of the corresponding gates and the corresponding sources of all the light-sensitive thin film transistors are the same.
In a third aspect, an embodiment of the present invention further provides a display device, including the display panel according to the second aspect.
The embodiment of the invention provides a light-sensing thin film transistor, a display panel and a display device, wherein the light-sensing thin film transistor comprises an active layer and a grid electrode positioned on the active layer, the active layer comprises a first doping area and second doping areas positioned on two sides of the first doping area, the doping concentration of the second doping areas is greater than that of the first doping areas, the two second doping areas correspondingly form a source electrode and a drain electrode of the light-sensing thin film transistor, the area of the grid electrode is smaller than that of the first doping area, the vertical projection of the first doping area covers the vertical projection of the grid electrode, the part, which is not shielded by the grid electrode, of the first doping area is used for adjusting photo-generated current generated by the light-sensing thin film transistor according to light reflected to the first doping area through a touch main body, further, the fingerprint identification function of the display panel can be realized through the detection of the photo-generated current generated by the light-sensing thin film transistor, and the fingerprint identification function of the display panel is realized through the light-sensing thin film transistor, so that the fingerprint identification function of the display panel is favorable for the large surface of the display panel Fingerprint identification is realized in the product range or even in the full screen range.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments of the present invention will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the contents of the embodiments of the present invention and the drawings without creative efforts.
FIG. 1 is a schematic cross-sectional view of a photosensitive TFT according to an embodiment of the present invention;
fig. 2 is a schematic top view of a display panel according to an embodiment of the present invention;
fig. 3 is a schematic cross-sectional structure diagram of a display panel according to an embodiment of the invention;
fig. 4 is a schematic top view of a display device according to an embodiment of the present invention.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. It should be further noted that, for the convenience of description, only some of the structures related to the present invention are shown in the drawings, not all of the structures.
As mentioned in the background of the invention, optical fingerprint recognition in the prior art is generally fixed position fingerprint recognition, i.e. the fingerprint sensor is fixed at a certain position in the screen body, mainly because the screen body has specially designed transmittance at the place where the fingerprint is collected, for example, the transmittance of light at the place is increased, and the fingerprint sensor is placed below the screen body at the position. With the development of fingerprint identification technology, how to realize large-area fingerprint identification even on a full screen becomes a development trend of future fingerprint identification, and at present, no good solution for the fingerprint identification requirement exists.
Based on the above technical problem, the present embodiment proposes the following solutions:
fig. 1 is a schematic cross-sectional view of a photosensitive thin film transistor according to an embodiment of the invention. As shown in fig. 1, the light sensing thin film transistor T1 includes an active layer 1 and a gate G1, the gate G1 is located above the active layer 1, the active layer 1 includes a first doped region a1 and second doped regions a2 located at two sides of the first doped region a1, the doping concentration of the second doped region a2 is greater than that of the first doped region a1, and two second doped regions a2 correspond to the source S and the drain D of the light sensing thin film transistor T1.
The light-sensing thin film transistor T1 shown in fig. 1 is a thin film transistor with a top gate structure, i.e. the gate G1 of the light-sensing thin film transistor T1 is located above the active layer 1, and exemplarily, the light-sensing thin film transistor T1 may be a LTPS (Low Temperature polysilicon) thin film transistor, which has high mobility and good stability. The photo-sensing thin film transistor T1 is an LTPS thin film transistor, that is, the photo-sensing thin film transistor T1 is a P-type thin film transistor, the first doped region a1 and the second doped region a2 of the active layer 1 of the photo-sensing thin film transistor T1 are both doped with P-type semiconductor materials, the doping concentration of the second doped region a2 is greater than that of the first doped region a1, so that the second doped region a2 can be defined as a heavily doped region, and the first doped region a1 is a lightly doped region.
The first doped region a1 is disposed corresponding to the gate G1 of the light sensing thin film transistor T1, the two second doped regions a2 are disposed corresponding to the source S and the drain D of the light sensing thin film transistor T1, the first doped region a1 forms a channel of the light sensing thin film transistor T1, when a difference between voltages applied to the gate G1 and the source S of the light sensing thin film transistor T1 is greater than a threshold voltage Vth of the light sensing thin film transistor T1, the source S and the drain D of the light sensing thin film transistor T1 are turned on, and the source S and the drain D of the light sensing thin film transistor T1 generate a flowing current.
As shown in fig. 1, the area of the gate G1 is smaller than the area of the first doped region a1, the vertical projection of the first doped region a1 covers the vertical projection of the gate G1, the first doped region a1 has a portion A4 disposed opposite to the gate G1 and a portion A3 not shielded by the gate G1, the gate G1 is an opaque metal structure, the portion A3 of the first doped region a1 not shielded by the gate G1 is not affected by the opaque gate G1, that is, the portion A3 of the first doped region a1 not shielded by the gate G1 can receive the light reflected by the touch body 2 and adjust the magnitude of the photo-generated current generated by the photo-sensing thin film transistor T1 according to the received reflected light, that is, i.e., adjust the magnitude of the current flowing through the source S and the drain D of the photo-sensing thin film transistor T1, the portion a 5928 of the first doped region a1 receives the reflected light, the first doped region a1 generates different amounts of the first doped carriers, the source S and drain D of the light sensing thin film transistor T1 are different in current.
Specifically, light emitted from the light source is irradiated to the touch main body 2, the touch main body 2 is usually a finger, the fingerprint is composed of a series of ridges 21 and valleys 22 on the skin surface of the finger tip, and since the distances from the ridges 21 and the valleys 22 to the first doping region a1 of the light-sensing thin film transistor T1 where the portion A3 is not shielded by the gate G1 are different, the intensity of the light reflected back by the ridges 21 and the valleys 22 received by the light-sensing thin film transistor T1 is different, so that the current values of the electrical signals converted by the light-sensing thin film transistor T1 from the reflected light formed at the position of the ridges 21 and the reflected light formed at the position of the valleys 22 are different, and fingerprint identification can be performed according to the different current values. Therefore, the fingerprint identification function of the display panel can be realized by detecting the photo-generated current generated by the light-sensitive thin film transistor T1, the display panel is also provided with a plurality of thin film transistors, the light-sensitive thin film transistor T1 is compatible with the processes of other thin film transistors in the display panel, and the light-sensitive thin film transistor T1 can be arranged in a large-area display area of the display panel and even in the whole display area of the display panel, namely, the light-sensitive thin film transistor T1 is utilized to realize the fingerprint identification function of the display panel, so that the fingerprint identification can be realized in a large-area range of the display panel and even in a full-screen range.
Alternatively, as shown in fig. 1, the ratio of the area of the portion A3 of the first doped region a1 in the active layer 1 of the photosensitive thin film transistor T1 not shielded by the gate electrode G1 to the area of the portion a4 of the first doped region a1 disposed opposite to the gate electrode G1 may be set to be 1.2 or more. Specifically, the ratio of the area of the portion A3 of the first doped region a1 in the active layer 1 of the light-sensing thin film transistor T1, which is not shielded by the gate G1, to the area of the portion a4 of the first doped region a1, which is disposed opposite to the gate G1, is too small, which is not favorable for increasing the area of the portion A3 of the first doped region a1 in the active layer 1 of the light-sensing thin film transistor T1, which is not shielded by the gate G1, and thus the number of photo-generated carriers generated after the first doped region a1 receives light reflected by the touch subject 2 is reduced, and the difference of photo-generated currents generated after the portion A3 of the first doped region a1, which is not shielded by the gate G1, receives reflected light with different intensities is reduced, which affects the accuracy of fingerprint identification performed by the light-sensing thin film transistor T1.
It should be noted that fig. 1 only exemplarily sets the gate G1 of the light-sensing thin film transistor T1 at one side of the first doped region a1 in the active layer 1, and the gate G1 of the light-sensing thin film transistor T1 may also be set at the rest position of the first doped region a1 in the active layer 1, so as to ensure that the first doped region a1 of the active layer 1 has a portion A3 that is not shielded by the gate G1.
The photosensitive thin film transistor T1 with the structure shown in fig. 1 can be formed by the following steps:
firstly, a-Si (amorphous silicon) is manufactured on a substrate 3, the substrate 3 can be made of glass or Polyethyleneimine (PI) for example, then the a-Si is converted into P-Si (polycrystalline silicon) by adopting an excimer laser annealing mode, a P-Si graph is manufactured by using a yellow light process, and then the patterned P-Si film layer is subjected to ion light doping to improve the threshold voltage of a light-sensitive thin film transistor T1. Then, a gate insulating layer 11 is formed, the gate insulating layer 11 may be made of a silicon oxide material, a gate G1 is formed, a gate G1 is made of a metal material such as molybdenum or aluminum, and then the patterned P-Si film is heavily doped with ions, the doping concentration is increased relative to the previous doping concentration when a channel is formed, so as to lay a foundation for realizing ohmic contact between the source electrode S1 and the source electrode S, and between the drain electrode D1 and the drain electrode D of the subsequent photo-sensing thin film transistor T1, the previous doping process forms the first doping region a1 of the active layer 1, and the subsequent doping process forms the second doping region a2 of the active layer 1.
Then, a yellow light process is adopted to manufacture a source contact hole and a drain contact hole, and finally, a source electrode S1 and a drain electrode D1 are manufactured. In addition, compared to the fabrication process of a common thin film transistor, the light sensing thin film transistor T1 needs to use a Mask to implement a process of heavily doping ions in the patterned P-Si film, for example, after the gate G1 is fabricated, a communication Mask is further performed to protect the first doped region a1 in fig. 1 with a photoresist, heavily dope ions in the portion not protected by the photoresist, i.e., the second doped region a2, and then the photoresist is stripped to form the complete active layer 1 of the light sensing thin film transistor T1 in fig. 1.
Fig. 2 is a schematic top view structure diagram of a display panel according to an embodiment of the present invention, and fig. 3 is a schematic cross-sectional structure diagram of a display panel according to an embodiment of the present invention. Referring to fig. 1 to 3, the display panel includes a plurality of light sensing tfts T1 according to the above embodiments, the light sensing tft T1 is used for adjusting the light-generated current generated by the light sensing tft T1 according to the light reflected to the light sensing tft T1 by the touch main body 2, that is, the light sensing tft T1 can perform fingerprint identification according to the above reflected light.
Alternatively, with reference to fig. 1 to 3, when the light sensing tft T1 performs fingerprint recognition, the potential difference between the gate G1 and the source S of all the light sensing tfts T1 may be set to be the same. Specifically, the current flowing through the source S and the drain D of the photo thin film transistor T1 is influenced by both the intensity of the light reflected by the touch body 2 irradiated to the portion of the first doped region a1 not shielded by the gate G1 and the potential difference of the electrical signals applied to the gate G1 and the source S of the photo thin film transistor T1, so that the current flowing through the source S and the drain D of the photo thin film transistor T1 is only influenced by the intensity parameter of the light reflected by the touch body 2 based on the portion of the first doped region a1 not shielded by the gate G1, the potential difference between the gate G1 and the source S corresponding to all the photo thin film transistors T1 can be set, and finally the intensity of the light reflected by the touch body 2 irradiated to the portion of the first doped region a1 not shielded by the gate G1 can be inversely compared by the detection of the current generated by the photo thin film transistor T1, the accuracy of fingerprint identification of the display panel is improved.
Alternatively, in conjunction with fig. 1 to 3, the display panel includes a display area AA and a non-display area NAA disposed around the display area AA, at least a portion of the display area AA of the display panel is provided with the light-sensing thin film transistor T1 of the above-described embodiment, preferably, the entire display area AA of the display panel may be provided with the light-sensing thin film transistor T1 of the above embodiment, fig. 2 exemplarily shows that the light-sensing thin film transistor T1 is uniformly distributed in the entire display area AA of the display panel, so that, while the fingerprint recognition function of the display panel is realized by the detection of the photo-generated current generated by the photo-sensing thin film transistor T1, the light-sensing tft T1 may be disposed in the display area AA of a larger area of the display panel or even in the entire display area AA of the display panel, that is, the light-sensing thin film transistor T1 is used to realize the fingerprint recognition function of the display panel, which is beneficial to realize the fingerprint recognition in a large area range of the display panel, even in a full screen range.
It should be noted that fig. 2 only exemplarily shows the setting conditions of the display area AA and the non-display area NAA of the display panel, which is not particularly limited in this embodiment of the present invention, and the display panel may also be a full-screen display panel.
Alternatively, with reference to fig. 1 to 3, the display panel further includes a substrate 3 and a plurality of light emitting structures 4, a plurality of light sensing thin film transistors T1 are located on the substrate 3, and a plurality of light emitting structures 4 are located on a side of the light sensing thin film transistor T1 away from the substrate 3, the light emitting structures 4 may be configured to provide a light source for the light sensing thin film transistor T1, and the light sensing thin film transistor T1 is configured to adjust a light generation current generated by the light sensing thin film transistor T1 according to light emitted by the light emitting structures 4 and reflected to the light sensing thin film transistor T1 via the touch main body 2, that is, perform fingerprint recognition.
Illustratively, the display panel may be, for example, an organic light emitting display panel, the light emitting structure 4 may be an organic light emitting structure, a dotted line indicated by an arrow in fig. 3 represents light emitted by the light emitting structure 4 and reflected to the light sensing thin film transistor T1 via the touch body 2, the display panel may include a light emitting side and a non-light emitting side, the light emitting side of the display panel in fig. 3 is above the display panel, and the non-light emitting side of the display panel may be below the display panel, that is, the display panel may be set to be a top emission structure, so that the light sensing thin film transistor T1 can receive the light emitted by the light emitting structure 4 and reflected back via the touch body 2.
Preferably, when the light sensing thin film transistor T1 is configured to perform fingerprint recognition, at least the green light emitting structure G provides a light source for the light sensing thin film transistor T1, the display panel further includes a planarization layer 30 located between the thin film transistor and the light emitting structure, the planarization layer 30 is configured to provide a flat manufacturing plane for the light emitting structure before the light emitting structure is formed, when the display panel is a flexible display panel, the material of the planarization layer 30 is PI material, the light emitted by the light emitting structure is reflected by the touch main body 2 and passes through the planarization layer 30 to irradiate the light sensing thin film transistor T1, when the light sensing thin film transistor T1 is configured to perform fingerprint recognition, at least the green light emitting structure G provides a light source for the light sensing thin film transistor T1, and by utilizing the characteristic that the planarization layer 30 made of PI material has high transmittance for green light, compared with the configuration that only the blue light emitting structure B or the red light emitting structure R provides a light source for the light sensing thin film transistor T1, the light intensity of the light emitted by the light emitting structure 4 and reflected by the touch main body 2 can be increased, and the number of photo-generated carriers generated after the first doping region a1 receives the light reflected by the touch main body 2 is increased, so that the difference of photo-generated currents generated after the part A3 of the first doping region a1 which is not shielded by the gate G1 receives reflected light with different light intensities is increased, and the accuracy of fingerprint identification of the light-sensitive thin film transistor T1 is improved.
Alternatively, in conjunction with fig. 1 to 3, at least two light emitting structures 4 with different light emitting colors in the display panel may be arranged to form one pixel unit 5, and for example, the display panel may include a red light emitting structure R, a green light emitting structure G and a blue light emitting structure B, one red light emitting structure R, a green light emitting structure G and a blue light emitting structure B are arranged to form one pixel unit 5, one light sensing thin film transistor T1 is arranged corresponding to at least one pixel unit 5, that is, each light sensing thin film transistor T1 is arranged corresponding to the corresponding pixel unit 5, and no pixel unit 5 is arranged corresponding to the partial light sensing thin film transistor T1, so that each light emitting thin film transistor can receive the light emitted by the light emitting structure 4 in the corresponding pixel unit 5 and reflected by the touch subject 2, and the light sensing thin film transistor T1 can receive the light emitted by the light emitting structure 4 and reflected by the touch subject 2 is improved The probability of lines ensures that each light-sensing thin film transistor T1 can help the display panel to realize the fingerprint identification function.
Preferably, with reference to fig. 1 to 3, the light sensing tfts T1 may be disposed in one-to-one correspondence with the pixel units 5, that is, a group of the red light emitting structures R, the green light emitting structures G, and the blue light emitting structures B is disposed, that is, a light sensing tft T1 is disposed in correspondence with each other, so that the light sensing tfts T1 are uniformly disposed in the display area AA of the display panel, that is, no matter where the user presses the display panel, there is a corresponding light sensing tft T1 for fingerprint recognition of the display panel.
Specifically, with reference to fig. 1 to fig. 3, when the light sensing tft T1 performs fingerprint identification, at least the green light emitting structure G provides a light source for the light sensing tft T1, that is, when fingerprint identification is performed on a light sensing tft T1, at least the green light emitting structure G in the pixel unit 5 corresponding to the light sensing tft T1 may be turned on, and the green light emitting structure G provides a light source for the corresponding light sensing tft T1.
Optionally, with reference to fig. 1 to fig. 3, the display panel further includes a plurality of pixel thin film transistors located on the substrate 3, where the pixel thin film transistors are configured to drive the corresponding light emitting structures 4 to emit light, each light emitting structure 4 is correspondingly provided with a pixel driving circuit, the pixel driving circuit includes a plurality of thin film transistors and a capacitor structure, the thin film transistors in the pixel driving circuit are defined as pixel thin film transistors, and the light emitting structures 4 emit light in response to the driving circuit provided by the corresponding pixel driving circuit, for example, the pixel thin film transistor corresponding to the red light emitting structure R is RT, the pixel thin film transistor corresponding to the green light emitting structure G is GT, and the pixel thin film transistor corresponding to the blue light emitting structure B is BT. The light-sensing thin film transistor T1 and the pixel thin film transistors RT, GT, and BT may be fabricated in the same layer, that is, the light-sensing thin film transistor T1 and the active layers and gates of the pixel thin film transistors RT, GT, and BT are fabricated in the same layer, which is beneficial to the arrangement of the light-sensing thin film transistor T1 corresponding to at least one pixel unit 5 to improve the probability that the light-sensing thin film transistor T1 receives the light emitted by the light-emitting structure 4 and reflected by the touch main body 2, and at the same time, the fabrication of the display panel is simplified.
Optionally, with reference to fig. 1 to 3, a lower electrode (not shown in fig. 3) disposed on a side of the light emitting structure 4 adjacent to the substrate 3 exposes at least a portion of the first doped region a1 of the portion A3 not shielded by the corresponding gate G1, the lower electrode of the light emitting structure 4 is located at a position where the light emitting structure 4 is located, that is, R, G and B in fig. 3 are located at positions where the lower electrode of the red light emitting structure R, the lower electrode of the green light emitting structure G and the lower electrode of the blue light emitting structure B are located, respectively, and the lower electrode (not shown in fig. 3) disposed on a side of the light emitting structure 4 adjacent to the substrate 3 exposes at least a portion of the portion A3 where the first doped region a1 is not shielded by the corresponding gate G1, that at least a portion of the first doped region a1 is not shielded by the gate G1 or by the lower electrode on a side of the light emitting structure 4 adjacent to the substrate 3, so as to ensure that light reflected by the touch body 2 can be shielded by the gate G1 and the lower electrode on a side of the light emitting structure 4 adjacent to the substrate 3 The electrode is shielded and irradiates the part of the first doping region A1 which is not shielded by the metal structure.
Preferably, with reference to fig. 1 to 3, a portion A3 of the first doped region a1, which is not shielded by the corresponding gate G1, of the lower electrode disposed on a side of the light emitting structure 4 adjacent to the substrate 3 may be set, and while the first doped region a1 satisfies that there is a portion a4 directly opposite to the gate G1 to form the photo-sensing thin film transistor T1, an area of the portion A3 of the first doped region a1, which is not shielded by the metal structure, is maximized to increase the number of photo-generated carriers generated by the first doped region a1 after receiving light reflected by the touch subject 2, so that a difference of photo-generated currents generated by the portion A3 of the first doped region a1, which is not shielded by the gate G1, after receiving reflected light of different light intensities is increased, which is beneficial to improve accuracy of fingerprint identification performed by the photo-sensing thin film transistor T1.
Fig. 4 is a schematic top view structure diagram of the display device according to the embodiment of the present invention. As shown in fig. 4, the display device 8 includes the display panel 7 of the above embodiment, so that the advantages of the above embodiment are provided, and are not described herein again. Illustratively, the display device 8 may be a digital device such as a mobile phone, a tablet, a palm computer, or an ipod.
It is to be noted that the foregoing is only illustrative of the preferred embodiments of the present invention and the technical principles employed. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments illustrated herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in greater detail by the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the spirit of the present invention, and the scope of the present invention is determined by the scope of the appended claims.
Claims (10)
1. A light-sensing thin film transistor, comprising:
the active layer comprises a first doping area and second doping areas positioned on two sides of the first doping area, the doping concentration of the second doping areas is greater than that of the first doping area, and the two second doping areas correspondingly form a source electrode and a drain electrode of the photosensitive thin film transistor;
the grid electrode is positioned above the active layer, the area of the grid electrode is smaller than that of the first doping region, the vertical projection of the first doping region covers the vertical projection of the grid electrode, and the part, which is not shielded by the grid electrode, of the first doping region is used for adjusting photo-generated current generated by the photo-sensing thin film transistor according to light reflected to the first doping region through a touch body;
the area of the part, which is not shielded by the grid electrode, of the first doping region is larger than the area of the part, which is opposite to the grid electrode, of the first doping region.
2. The light-sensing thin film transistor as claimed in claim 1, wherein a ratio of an area of the first doped region not covered by the gate to an area of a portion of the first doped region opposite to the gate is 1.2 or more.
3. A display panel comprising a plurality of photosensitive thin film transistors according to claim 1 or 2.
4. The display panel according to claim 3, wherein at least a part of the display region of the display panel is provided with the light-sensitive thin film transistor.
5. The display panel according to claim 4, further comprising:
the light sensing thin film transistor is positioned on the substrate, and the light emitting structures are positioned on one side, far away from the substrate, of the light sensing thin film transistor;
when the light sensation thin film transistor is used for fingerprint identification, at least a green light-emitting structure provides a light source for the light sensation thin film transistor, and the light sensation thin film transistor is used for adjusting the photoproduction current generated by the light sensation thin film transistor according to the light rays emitted by the light-emitting structure and reflected to the light sensation thin film transistor through the touch main body.
6. The display panel according to claim 5, wherein at least two of the light emitting structures emitting different colors of light form a pixel unit, and one of the light sensing thin film transistors is disposed corresponding to at least one of the pixel units.
7. The display panel according to claim 5 or 6, characterized by further comprising:
and the light sensing thin film transistors and the pixel thin film transistors are manufactured in the same layer.
8. The display panel according to claim 5 or 6, wherein the lower electrode disposed on a side of the light emitting structure adjacent to the substrate exposes at least a portion of the first doped region not covered by the corresponding gate.
9. The display panel according to any one of claims 3 to 6, wherein the photosensitive TFTs have the same potential difference between the gate and the source when performing fingerprint identification.
10. A display device characterized by comprising the display panel according to any one of claims 3 to 9.
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| CN112086526B (en) * | 2020-09-01 | 2023-11-28 | 深圳市华星光电半导体显示技术有限公司 | Display panel and display device |
| CN112420618B (en) * | 2020-11-17 | 2024-02-02 | 武汉华星光电半导体显示技术有限公司 | Display panel and preparation method thereof |
| CN112736097B (en) * | 2021-01-19 | 2023-10-03 | Tcl华星光电技术有限公司 | Display device and manufacturing method thereof |
| CN113113354B (en) * | 2021-03-18 | 2022-04-08 | 武汉华星光电技术有限公司 | Optical device, preparation method thereof and display panel |
| CN113363343A (en) * | 2021-05-31 | 2021-09-07 | Tcl华星光电技术有限公司 | Semiconductor device and photosensitive device |
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