CN111863912A - OLED display panel with fingerprint identification function, display device and preparation method - Google Patents
OLED display panel with fingerprint identification function, display device and preparation method Download PDFInfo
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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
- H10K59/40—OLEDs integrated with touch screens
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F3/00—Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
- G06F3/01—Input arrangements or combined input and output arrangements for interaction between user and computer
- G06F3/03—Arrangements for converting the position or the displacement of a member into a coded form
- G06F3/041—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
- H01L27/02—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components specially adapted for rectifying, oscillating, amplifying or switching and having at least one potential-jump barrier or surface barrier; including integrated passive circuit elements with at least one potential-jump barrier or surface barrier
- H01L27/12—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components specially adapted for rectifying, oscillating, amplifying or switching and having at least one potential-jump barrier or surface barrier; including integrated passive circuit elements with at least one potential-jump barrier or surface barrier the substrate being other than a semiconductor body, e.g. an insulating body
- H01L27/1214—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components specially adapted for rectifying, oscillating, amplifying or switching and having at least one potential-jump barrier or surface barrier; including integrated passive circuit elements with at least one potential-jump barrier or surface barrier the substrate being other than a semiconductor body, e.g. an insulating body comprising a plurality of TFTs formed on a non-semiconducting substrate, e.g. driving circuits for AMLCDs
- H01L27/1251—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components specially adapted for rectifying, oscillating, amplifying or switching and having at least one potential-jump barrier or surface barrier; including integrated passive circuit elements with at least one potential-jump barrier or surface barrier the substrate being other than a semiconductor body, e.g. an insulating body comprising a plurality of TFTs formed on a non-semiconducting substrate, e.g. driving circuits for AMLCDs comprising TFTs having a different architecture, e.g. top- and bottom gate TFTs
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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
- H10K59/121—Active-matrix OLED [AMOLED] displays characterised by the geometry or disposition of pixel elements
- H10K59/1213—Active-matrix OLED [AMOLED] displays characterised by the geometry or disposition of pixel elements the pixel elements being TFTs
Abstract
The application discloses an OLED display panel with a fingerprint identification function, a display device and a preparation method of the OLED display panel, the display device and the preparation method of the OLED display panel with the fingerprint identification function, wherein a plurality of double-gate TFTs and a plurality of single-gate TFTs are formed on a substrate, a PIN photodiode is arranged above each double-gate TFT, and the N electrode of each PIN photodiode is connected to the top gate of each double-gate TFT; and a light emitting layer is arranged on one side of the PIN photodiode far away from the double-gate TFT, the light emitting layer comprises a plurality of sub-pixels arranged at intervals, and the PIN photodiode is arranged between the sub-pixels. According to the technical scheme provided by the embodiment of the application, the plurality of PIN photodiodes and the double-gate TFT connected with the PIN photodiodes are arranged on the display panel, so that the source flow current of the double-gate TFT is acted by bottom gate bias voltage and top gate bias voltage caused by the PIN photodiodes, namely the turn-on voltage V of the double-gate TFTThBecause the light-induced change causes the current quantity of the output to change, thereby realizing the function of fingerprint identification.
Description
Technical Field
The invention relates to the field of display, in particular to an OLED display panel with a fingerprint identification function, a display device and a preparation method.
Background
Not only application fields of the organic light emitting display device are diversified, but also some products are gradually developed to be multifunctional, such as optical in-screen fingerprints. At present, fingerprint identification technologies mainly comprise a capacitance type, an optical type and an ultrasonic type, and the capacitance type can only be integrated and covered due to the limitation of a penetration distance and cannot be used under a screen; ultrasonic type is not easy to integrate into the screen due to material limitation. The screen only adopts an optical type and an ultrasonic type which meet the requirements of the full screen, not only meets the requirements of the full screen and the large screen, but also can integrate the screen, and preferably adopts the optical type.
The traditional optical fingerprint technology under the screen comprises the following steps: a collimating layer scheme and an aperture imaging scheme. The collimating layer in the collimating layer scheme is a layer plate, a plurality of light channels are arranged on the layer plate, except the light channels, shading materials are adopted in other areas. Under this kind of structure, the light that comes from the fingerprint passes through behind cover plate glass, the OLED layer, gets into the collimation layer, and then filters refraction and scattered light, and the light that reaches light sensing element is just collimated light, obtains relatively clear fingerprint image, final discernment fingerprint. Although the collimating layer scheme solves part of imaging problems, due to the fact that cover plate glass and an OLED display screen exist in a mobile phone structure, the distance from a fingerprint module under the screen to the surface of the screen is about 0.5 mm, an obtained image is still relatively fuzzy, and therefore the small-hole imaging scheme comes into force. In the pinhole imaging scheme, the collimator is composed of two thin plates with pinholes and a light-transmitting material sandwiched between the thin plates. Can effectively reduce structure thickness, also can reduce the loss of the light of turning back simultaneously, increase the printing opacity for the image that reaches light sensor is more clear.
However, regardless of the alignment layer scheme or the pinhole imaging scheme, how large the fingerprint identification area is made, how large the fingerprint identification sensor is required, and the cost is expensive.
Disclosure of Invention
In view of the above-mentioned drawbacks and deficiencies of the prior art, it is desirable to provide an OLED display panel with fingerprint identification function, a display device and a manufacturing method thereof.
In a first aspect, an OLED display panel with a fingerprint identification function is provided, and comprises a substrate, wherein a plurality of double-gate TFTs and a plurality of single-gate TFTs are formed on the substrate, a PIN photodiode is arranged above each double-gate TFT, and the N electrode of each PIN photodiode is connected to the top gate of each double-gate TFT;
and a light emitting layer is arranged on one side of the PIN photodiode, which is far away from the double-gate TFT, the light emitting layer comprises a plurality of sub-pixels which are arranged at intervals, and the PIN photodiode is arranged between the sub-pixels.
In a second aspect, an OLED display device is provided, which includes the above OLED display panel with fingerprint identification function.
In a third aspect, a method for manufacturing an OLED display panel with a fingerprint identification function is provided, which includes the steps of:
providing a substrate, forming a plurality of double-gate TFTs and a plurality of single-gate TFTs on the substrate,
forming a PIN photodiode above each double-gate TFT, wherein the N electrodes of the PIN photodiodes are connected to the top gates of the double-gate TFTs;
and a light emitting layer is arranged on one side of the PIN photodiode, which is far away from the double-gate TFT, the light emitting layer comprises a plurality of sub-pixels which are arranged at intervals, and the PIN photodiode is arranged between the sub-pixels.
According to the technical scheme provided by the embodiment of the application, the plurality of PIN photodiodes and the double-gate TFT connected with the PIN photodiodes are arranged on the display panel, so that the source flow current of the double-gate TFT is biased by a bottom gate and the source flow current of the double-gate TFT is biased by the bottom gateThe common effect of the top-gate bias for the PIN photodiode, i.e. the turn-on voltage V of the double-gate TFTThThe light-induced change causes the change of the output current, thereby realizing the function of fingerprint identification; furthermore, the PIN photodiode is arranged between the light-emitting layer and the TFT structure, the path through which the optical signal reflected by the finger passes is short, the light energy loss is less, and the accuracy of fingerprint identification can be improved.
Drawings
Other features, objects and advantages of the present application will become more apparent upon reading of the following detailed description of non-limiting embodiments thereof, made with reference to the accompanying drawings in which:
fig. 1 is a schematic structural diagram of an OLED display panel with a fingerprint identification function in this embodiment;
FIG. 2 is an equivalent circuit diagram of the PIN photodiode and the dual-gate TFT in the present embodiment;
fig. 3 is a flowchart of a method for manufacturing an OLED display panel with a fingerprint identification function according to this embodiment.
Detailed Description
The present application will be described in further detail with reference to the following drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the relevant invention and not restrictive of the invention. It should be noted that, for convenience of description, only the portions related to the present invention are shown in the drawings.
It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict. The present application will be described in detail below with reference to the embodiments with reference to the attached drawings.
Referring to fig. 1, the present embodiment provides an OLED display panel with fingerprint identification function, including a substrate 1, a plurality of double-gate TFTs 2 and a plurality of single-gate TFTs 3 are formed on the substrate 1, a PIN photodiode 8 is disposed above each double-gate TFT2, and an N-gate 81 of each PIN photodiode 8 is connected to a top-gate 23 of the double-gate TFT 2;
the side of the PIN photodiode 8 remote from the double gate TFT2 is provided with a light emitting layer 10, the light emitting layer 10 includes a plurality of sub-pixels 11 arranged at intervals, and the PIN photodiode 8 is arranged between the sub-pixels 11.
The OLED display panel provided in this embodiment is provided with a plurality of PIN photodiodes 8, and the PIN photodiodes 8 are connected to the double-gate TFT2, so that the source-drain current is acted by the bottom-gate bias voltage and the top-gate bias voltage caused by the PIN photodiodes, that is, the turn-on voltage V of the double-gate TFTThBecause the light-induced change causes the current quantity of the output to change, thereby realizing the function of fingerprint identification. In this embodiment, the PIN photodiode 8 is arranged between the sub-pixels 11 of the light-emitting layer 10, the PIN photodiode 8 and the double-gate TFT2 are arranged in the area where fingerprint identification is required, the whole screen can be further expanded, the fingerprint identification function of the whole screen is realized, and the fingerprint identification of the large screen is realized.
Fig. 2 is an equivalent circuit diagram of the fingerprint identification function of the OLED display panel in this embodiment, in which a PIN photodiode is arranged to receive and convert an optical signal reflected by a finger into an electrical signal, and the PIN photodiode is connected to a dual-gate TFT, so that a source-drain current has a bottom-gate bias and a top-gate bias caused by the PIN photodiode, that is, a turn-on voltage V of the dual-gate TFTThBecause the light-induced change causes the current quantity of the output to change, thereby realizing the function of fingerprint identification.
Meanwhile, the circuit connection form of the PIN photodiode and the double-gate TFT connected with each other provided by the embodiment can realize the function of amplifying the input optical signal, so that the sensitivity of fingerprint identification in the screen of the display panel is greatly improved, and the following calculation steps are the process of amplifying the optical signal:
wherein the turn-on voltage V of the double-gate TFTTh，VTH＝VT0+γ·VIG(ii) a Wherein VT0Is the threshold voltage in the absence of illumination, and gamma is a parameter of the photosensitive device.
VIGIs connected with the photodiode capacitance (C) in the absence of illuminationDiode) To aFunction of (c):
When illuminated, charges (Q) are generated by lighte) Raising the top gate voltage (from V)IGIs lifted to VIG’)。
Qe＝qηΦλtsTtop(1-e-αt)，QeIs a function associated with the photodiode; η is the diode collection efficiency; phiλIs the photon flux; t is tsTime of sample, TtopThe transmittance of ITO and P layers; 1-e-αtFor the internal quantum efficiency of the photodiode, a is the absorption coefficient and t is the I-layer film thickness, i.e. the thickness of the intermediate a-Si layer of the PIN photodiode.
Further, in the present embodiment, the PIN photodiode 8 for receiving the light reflected by the finger 15 is disposed between the light emitting layer 10 and the TFT2, 3 structure, and the light signal reflected by the finger 15 passes through the touch film layer, the encapsulation layer, and the like to reach the PIN photodiode 8, so as to receive the light reflected by the finger and convert the light signal into an electrical signal.
Further, an upper electrode layer 13 is disposed between the PIN photodiode 8 and the light emitting layer 10, and the upper electrode layer 13 is connected to the P-pole 83 of the PIN photodiode 8.
In the embodiment, the upper electrode layer 13 is arranged on the P pole 83 of the PIN photodiode 8, the upper electrode layer 13 is connected to the signal metal wire 14, the PIN photodiode 8 receives an optical signal and converts the optical signal into an electrical signal, and the upper electrode layer 13 is connected with the signal metal wire 14 to realize transmission of the electrical signal.
Further, the upper electrode layer 13 is a transparent electrode layer. In this embodiment, a transparent material is used for preparing the upper electrode, preferably ITO (thin film, i.e. indium tin oxide semiconductor transparent conductive film) is used as the material for preparing the upper electrode, and a transparent material is used for the photodiode to receive the optical signal reflected by the finger, as shown in fig. 1, the light of the light emitting layer 10 is reflected by the fingerprint on the finger 15 to the display panel, and is transmitted to the PIN photodiode 8 through the transparent upper electrode 13 to perform the conversion from the optical signal to the electrical signal.
Further, a PIN photodiode 8 and a double gate TFT2 connected to the PIN photodiode 8 are provided between each adjacent sub-pixel 11.
In the embodiment, the PIN photodiode 8 is additionally arranged between the light emitting layer 10 and the TFT for receiving and detecting optical signals, and the PIN photodiode 8 can be arranged at a position where fingerprint detection is required; furthermore, the PIN photodiode 8 is arranged between the light-emitting layer 10 and the TFT, so that the influence on the display panel per se is small, and the influence on the process and the panel caused by the number of the PIN photodiodes prepared in the backboard preparation process is not greatly different, so that the PIN photodiodes and the double-gate TFT connected with the PIN photodiodes can be arranged between every two sub-pixels, the fingerprint identification function of the whole screen is realized, and the cost is low.
Further, each PIN photodiode 8 comprises a P-type amorphous silicon film layer 83, an amorphous silicon film layer 82 and an N-type amorphous silicon film layer 81 which are connected in sequence, and the thickness of the amorphous silicon film layer 82 is 6K-10K angstroms.
In this embodiment, the PIN photodiode 8 receives the optical signal, converts the optical signal into an electrical signal, and performs the optical signalFunction of amplification, according to the preceding embodiment, wherein IPhotoThe numerical value is influenced by a plurality of parameters, the amplification of the PIN photodiode on optical signals is influenced by the thickness of the amorphous silicon film layer, namely the A-Si film layer 82 of the PIN photodiode 8, so that the thickness of the A-Si film layer is set to be 6K-10K angstroms, further, the thickness of the P-type amorphous silicon film layer and the thickness of the N-type amorphous silicon film layer are set to be 300-500 angstroms, and the sensitivity and the effect of fingerprint identification are guaranteed.
As shown in fig. 1, the display panel in this embodiment is provided with a substrate 1, a buffer layer 4 is provided on the substrate 1, i.e., on the side away from the glass of the substrate 1, a TFT structure is provided on the buffer layer 4, the TFT structure in this embodiment includes two kinds of TFTs, a single-gate TFT3 and a double-gate TFT2 connected to a PIN photodiode 8, a bottom gate layer 21 of the double-gate TFT2 is provided on the substrate 1, covered with the buffer layer 4, a polysilicon layer 31 of the single-gate TFT3 structure and a polysilicon layer 22 of the double-gate TFT2 are provided on the buffer layer 4, a first gate insulating layer 5 is further provided on the buffer layer 4, the polysilicon layers 31, 22 are covered with the first gate insulating layer 5, a gate layer 32 of the single-gate TFT3 and a top gate layer 23 of the double-gate TFT2 are provided on the first gate insulating layer 5, the top gate layer 23 is provided directly above the bottom gate layer 21, two gate structures of the double-gate TFT2 are formed, a second gate insulating layer 6 and, source and drain layers 33, 24 are provided on the spacer layer 7, and openings are made in the second gate insulating layer 6 and the spacer layer 7 so that the source and drain layers are connected to the polysilicon layer, the PIN photodiode 8 in this embodiment is provided above the double-gate TFT2, and the N-electrode 81 of the PIN photodiode 8 is connected to the top gate layer 23 of the double-gate TFT2, the second gate insulating layer 6, the spacer layer 7 is provided around the PIN photodiode 8, and then the planarization layer 9 is formed on the spacer layer 7, the planarization layer 9 is provided so as to cover the PIN photodiode 8 and the spacer layer 7, planarization is performed, the anode layer 12 and the upper electrode layer 14 are provided on the planarization layer 9, the anode layer 12 is connected to the source and drain layers 33 of the single-gate TFT, the upper electrode layer 14 is connected to the P-electrode layer 83 of the PIN photodiode 8, the upper electrode layer 13 is also connected to the signal metal line 14, the sub-pixels 11 of the light-emitting layer 10 are not arranged above the PIN photodiodes 8, the PIN photodiodes 8 in the formed panel are located between the sub-pixels 11, and the light-emitting layer is further provided with a packaging layer and other structures, which belong to the field of the prior art and are not described herein again.
The embodiment also provides an OLED display device which comprises the OLED display panel with the fingerprint identification function.
As shown in fig. 3, the present embodiment provides a flowchart of a method for manufacturing an OLED display panel with a fingerprint identification function, including the steps of:
providing a substrate 1, forming a plurality of double-gate TFTs 2 and a plurality of single-gate TFTs 3 on the substrate 1,
forming a PIN photodiode 8 above each double-gate TFT2, the N-gates 81 of the PIN photodiodes 8 being connected to the top gate 23 of the double-gate TFT 2;
the side of the PIN photodiode 8 remote from the double gate TFT2 is provided with a light emitting layer 10, the light emitting layer 10 includes a plurality of sub-pixels 11 arranged at intervals, and the PIN photodiode 8 is arranged between the sub-pixels 11.
The preparation method adopted in the embodiment is used for preparing the OLED display panel, the preparation process is simple, the double-gate TFT and the PIN photodiode are arranged in the process of preparing the back plate of the display panel, excessive process steps do not need to be added, meanwhile, when the optical fingerprint module is attached to the OLED screen in the traditional optical fingerprint scheme, the screen can be damaged at a certain probability in the attaching process, and the attaching yield can also have a certain problem.
Further, an upper electrode layer 13 is formed between the PIN photodiode 8 and the light emitting layer 10, the upper electrode layer 13 is connected to the N-pole 83 of the PIN photodiode 8, and the upper electrode layer 13 is a transparent electrode layer. In the embodiment, the transparent material is adopted to prepare the upper electrode, so that the PIN photodiode can receive optical signals conveniently.
Further, the formation of the double-gate TFT2 and the single-gate TFT3 on the substrate 1 specifically includes the steps of: a bottom gate layer 21 of a double gate TFT2 is formed on a substrate 1, a buffer layer 4 is provided on the bottom gate layer 21, the buffer layer 4 is provided so as to cover the bottom gate layer 21,
forming a polycrystalline silicon layer on one surface, far away from the substrate 1, of the buffer layer 4, arranging a first grid insulation layer 5 on the polycrystalline silicon layer, and covering the polycrystalline silicon layer with the first grid insulation layer 5;
forming a gate layer on the first gate insulating layer 5, wherein the gate layer comprises a top gate layer 23 of the double-gate TFT2 and a gate layer 32 of the single-gate TFT2, and the top gate layer 23 is arranged corresponding to the bottom gate layer 21;
a second gate insulating layer 6 and an isolation layer 7 are sequentially arranged on the first gate insulating layer 5, and the second gate layer 6 covers the gate layer;
and a source drain electrode layer is arranged on the isolation layer 7, via holes are formed in the isolation layer and the second gate insulating layer 6, and the source drain electrode layer is connected to the polycrystalline silicon layer through the via holes.
In the embodiment, a double-gate TFT connected to a PIN photodiode is provided to realize a fingerprint recognition function, and a specific principle is described in the above embodiment, which is not to mention a lot, wherein the double-gate TFT and a single-gate TFT on a display panel are prepared together, a polysilicon layer of the double-gate TFT and a polysilicon layer of the single-gate TFT are arranged on the same layer, a gate layer of the top-gate TFT and a gate layer of the single-gate TFT are arranged on the same layer, the preparation is simple, a bottom gate layer of the double-gate TFT is arranged on a substrate, a step of arranging a bottom gate layer structure is added to a preparation process, other process steps are the same as a conventional TFT arrangement mode, the process change is small, and the operation is simple.
Further, forming a PIN photodiode above each dual gate TFT specifically includes the steps of:
an amorphous silicon film layer is deposited on the top gate layer of the double-gate TFT,
introducing phosphine gas to one side of the amorphous silicon film layer close to the top gate layer, and arranging an N-type amorphous silicon film layer on one side of the amorphous silicon film layer close to the top gate layer;
introducing borane gas to one side of the amorphous silicon film layer, which is far away from the top gate layer, and arranging a P-type amorphous silicon film layer on one side of the amorphous silicon film layer, which is far away from the top gate layer.
In the embodiment, the PIN photodiode is arranged on the top gate layer, the specific arrangement mode of the PIN photodiode is various, the preparation method is selected according to the field equipment condition, if the field chemical vapor deposition equipment is provided with an air inlet channel, different gases can be introduced through the equipment to carry out arrangement of a P-layer structure and an N-layer structure, an amorphous silicon film layer, namely an A-Si film layer, is firstly deposited, and then different gases are introduced to different surfaces of the A-Si film layer to carry out doping of the P-type film layer and the N-type film layer.
Further, forming a PIN photodiode above each dual gate TFT specifically includes the steps of:
an amorphous silicon film layer is deposited on the top gate layer of the double-gate TFT,
doping the side, close to the top gate layer, of the amorphous silicon film layer by adopting implantation equipment to form an N-type amorphous silicon film layer;
and doping the side of the amorphous silicon film layer, which is far away from the top gate layer, by adopting implantation equipment to form a P-type amorphous silicon film layer.
If the equipment on the display panel preparation site does not have an air inlet channel, different film layers can be doped through common implantation equipment, firstly, the A-Si film layer is deposited through chemical vapor deposition equipment, and then, different doping is carried out through the implantation equipment to form an N-type film layer and a P-type film layer.
In the above-described display panel manufacturing method, the PIN photodiode is manufactured in the back plate manufacturing process, and three to four process steps are added on the basis of the existing OLED panel manufacturing process to realize the manufacturing of the PIN photodiode and the double-gate TFT, so that the fingerprint identification function of the OLED display panel is realized, the process is simple and easy to operate, and the resources are saved.
Meanwhile, the positions of the PIN photodiode and the double-gate TFT added in the implementation are only required to be arranged between adjacent sub-pixels, compared with the modes of arrangement of the collimation holes and the like in the prior art, the problems of size, correspondence and the like of the corresponding collimation holes do not need to be considered, and the process is simpler.
The flow of the OLED display panel fabrication process described herein provides a substrate, a bottom gate layer formed on the substrate, a buffer layer disposed on the bottom gate layer, the buffer layer disposed overlying the bottom gate layer,
forming a polycrystalline silicon layer on the buffer layer, and arranging a first grid insulating layer on the polycrystalline silicon layer, wherein the first grid insulating layer covers the polycrystalline silicon layer;
forming a grid layer on the first grid insulating layer, wherein the grid layer comprises a top grid layer of a double-grid TFT and a grid layer of a single-grid TFT, and the top grid layer and the bottom grid layer are arranged correspondingly;
a PIN photodiode is arranged on the top gate layer, and an N electrode layer of the PIN photodiode is connected with the top gate layer;
arranging a second grid electrode insulating layer and an isolating layer on the first grid electrode insulating layer, wherein the second grid electrode layer is arranged to cover the grid electrode layer;
through holes are formed in the isolation layer and the second gate insulation layer, and then source and drain layers are arranged on the isolation layer and connected to the polycrystalline silicon layer through the through holes;
forming a planarization layer on the isolation layer, the planarization layer covering the source/drain layer and the PIN photodiode, forming an electrode pattern on the planarization layer,
forming an electrode layer on the flat layer, wherein the motor layer comprises an anode layer and an upper electrode layer, the anode layer is connected to the source drain electrode layer, the upper electrode layer is connected with the P electrode layer of the PIN photodiode,
and forming a light-emitting layer on the electrode layer, wherein the light-emitting layer comprises a plurality of sub-pixels arranged at intervals, and then forming other structures such as an encapsulation layer on the light-emitting layer.
In the embodiment, the double-gate TFT and PIN photodiodes are prepared on the OLED display panel, so that the OLED display panel has the function of optical fingerprint identification, and meanwhile, the function of comprehensive screen fingerprint identification can be realized, wherein the PIN photodiodes are prepared in the process of preparing the backboard of the OLED panel, the process is simple, and the production requirements are met.
The above description is only a preferred embodiment of the application and is illustrative of the principles of the technology employed. It will be appreciated by a person skilled in the art that the scope of the invention as referred to in the present application is not limited to the embodiments with a specific combination of the above-mentioned features, but also covers other embodiments with any combination of the above-mentioned features or their equivalents without departing from the inventive concept. For example, the above features may be replaced with (but not limited to) features having similar functions disclosed in the present application.
Claims (10)
1. The OLED display panel with the fingerprint identification function is characterized by comprising a substrate, wherein a plurality of double-gate TFTs and a plurality of single-gate TFTs are formed on the substrate, a PIN photodiode is arranged above each double-gate TFT, and the N electrode of each PIN photodiode is connected to the top gate of each double-gate TFT;
and a light emitting layer is arranged on one side of the PIN photodiode, which is far away from the double-gate TFT, the light emitting layer comprises a plurality of sub-pixels which are arranged at intervals, and the PIN photodiode is arranged between the sub-pixels.
2. The OLED display panel with fingerprint identification function of claim 1, wherein an upper electrode layer is disposed between the PIN photodiode and the light emitting layer, and the upper electrode layer is connected to a P pole of the PIN photodiode.
3. The OLED display panel with fingerprint identification function of claim 2, wherein the upper electrode layer is a transparent electrode layer.
4. The OLED display panel with fingerprint identification function of any one of claims 1 to 3, wherein said PIN photodiode and a double gate TFT connected to said PIN photodiode are disposed between each adjacent sub-pixels.
5. The OLED display panel with the fingerprint identification function of claim 4, wherein the PIN photodiodes each comprise a P-type amorphous silicon film layer, an amorphous silicon film layer and an N-type amorphous silicon film layer which are connected in sequence, and the thickness of the amorphous silicon film layer is 6K-10K angstroms.
6. An OLED display device, comprising the OLED display panel with fingerprint identification function of any one of claims 1-5.
7. A method for preparing the OLED display panel with the fingerprint identification function according to any one of claims 1 to 5, wherein the method comprises the following steps:
providing a substrate, forming a plurality of double-gate TFTs and a plurality of single-gate TFTs on the substrate,
forming a PIN photodiode above each double-gate TFT, wherein the N electrodes of the PIN photodiodes are connected to the top gates of the double-gate TFTs;
and a light emitting layer is arranged on one side of the PIN photodiode, which is far away from the double-gate TFT, the light emitting layer comprises a plurality of sub-pixels which are arranged at intervals, and the PIN photodiode is arranged between the sub-pixels.
8. The method as claimed in claim 7, wherein an upper electrode layer is formed between the PIN photodiode and the light emitting layer, the upper electrode layer is connected to an N-pole of the PIN photodiode, and the upper electrode layer is a transparent electrode layer.
9. The method for manufacturing the OLED display panel with the fingerprint identification function according to claim 8, wherein the step of forming the PIN photodiode above each of the dual-gate TFTs specifically comprises the steps of:
depositing an amorphous silicon film layer on the top gate layer of the double-gate TFT,
introducing phosphine gas to one side of the amorphous silicon film layer close to the top gate layer, and arranging an N-type amorphous silicon film layer on one side of the amorphous silicon film layer close to the top gate layer;
and introducing borane gas to one side of the amorphous silicon film layer, which is far away from the top gate layer, and arranging a P-type amorphous silicon film layer on one side of the amorphous silicon film layer, which is far away from the top gate layer.
10. The method for manufacturing the OLED display panel with the fingerprint identification function according to claim 8, wherein the step of forming the PIN photodiode above each of the dual-gate TFTs specifically comprises the steps of:
depositing an amorphous silicon film layer on the top gate layer of the double-gate TFT,
doping the side, close to the top gate layer, of the amorphous silicon film layer by adopting implantation equipment to form an N-type amorphous silicon film layer;
and doping the side of the amorphous silicon film layer, which is far away from the top gate layer, by adopting implantation equipment to form a P-type amorphous silicon film layer.
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Application publication date: 20201030 |