CN114023795A

CN114023795A - PM display panel and display device

Info

Publication number: CN114023795A
Application number: CN202111260100.4A
Authority: CN
Inventors: 周旭; 马中生; 穆欣炬; 唐鹏宇
Original assignee: Yiwu Qingyue Optoelectronic Technology Research Institute Co Ltd
Current assignee: Yiwu Qingyue Optoelectronic Technology Research Institute Co Ltd
Priority date: 2021-10-28
Filing date: 2021-10-28
Publication date: 2022-02-08

Abstract

The embodiment of the invention discloses a PM display panel and a display device. The PM display panel comprises a display area and a non-display area, and further comprises a plurality of first driving signal lines, a plurality of second driving signal lines, a plurality of thin film transistors and a plurality of light emitting diodes; the plurality of thin film transistors and the plurality of light emitting diodes are positioned in the display area and arranged in an array; the grid electrode of each row of thin film transistors is connected with a first driving signal line; the first pole of each row of thin film transistors is connected with a second driving signal line; the second pole of a thin film transistor is connected with the first pole of a light emitting diode, and the first poles of the light emitting diodes connected with the thin film transistors in the same row are connected with each other. According to the embodiment of the invention, the thin film transistor is introduced into the PM display panel, the grid electrode of the transistor can independently control the on or off of the light emitting diode, so that crosstalk among pixel points is avoided, more light emitting diodes can be arranged, the problem that the size and the number of the pixel points are limited is solved, and the imaging quality of the PM display panel is effectively improved.

Description

PM display panel and display device

Technical Field

Embodiments of the present invention relate to display technologies, and in particular, to a PM display panel and a display device.

Background

PMOLED (Passive Matrix OLED) has a cathode and an anode in a Matrix form, pixels in the array are lighted by scanning, and each pixel operates in a short pulse mode and emits light with high brightness instantaneously. The advantages are simple structure, low cost, high driving voltage and high current, and the PMOLED is not suitable for large-size and high-resolution panel. With the deep application of PMOLEDs in various fields, the market puts higher demands on the product size diversification, which requires the optimized upgrade of the driving mode of PMOLEDs. Due to the special driving mode of the PMOLED, the problems of high energy consumption, large heat productivity and uneven brightness exist.

Disclosure of Invention

The invention provides a PM display panel and a display device, which can avoid crosstalk among pixel points, solve the problem of limited size and number of the pixel points and effectively improve the imaging quality of the PM display panel.

In a first aspect, an embodiment of the present invention provides a PM display panel, including a display area and a non-display area, where the display panel further includes a plurality of first driving signal lines, a plurality of second driving signal lines, a plurality of thin film transistors, and a plurality of light emitting diodes; the thin film transistors and the light emitting diodes are positioned in the display area and are arranged in an array;

the grid electrode of each row of the thin film transistors is connected with one first driving signal line; the first pole of each row of the thin film transistors is connected with one second driving signal line; the second pole of the thin film transistor is connected with the first pole of the light emitting diode, and the first poles of the light emitting diodes connected with the thin film transistor in the same row are connected with each other.

Optionally, the second pole of each of the light emitting diodes is grounded.

Optionally, the PM display panel further includes a driving chip, the driving chip is connected to the first driving signal line and the second driving signal line, and the second pole of each of the light emitting diodes is not grounded through the driving chip.

Optionally, the display panel further comprises a plurality of third driving signal lines;

the second pole of each row of the light-emitting diodes is connected with one third driving signal line; each of the third driving signal lines is grounded.

Alternatively, each of the third driving signal lines is grounded after being connected to each other.

Optionally, the third driving signal lines are connected to a frame of the display panel.

Optionally, the display panel includes:

a substrate;

the thin film transistor layer, the first metal layer and the pixel defining layer are sequentially positioned on the substrate;

wherein the thin film transistor layer forms the thin film transistor; the first metal layer comprises a plurality of first electrodes, and one row of the thin film transistors is connected with one first electrode; the pixel defining layer is provided with openings, and the pixel defining layer includes a plurality of openings exposing a portion of one of the first electrodes.

Optionally, the PM display panel further includes a light emitting functional layer and a second electrode disposed on a side of the first electrode away from the substrate; the light emitting function layer is disposed in the opening and between the first electrode and the second electrode.

Optionally, the material of the first electrode comprises aluminum, and the material of the second electrode comprises ITO, magnesium-silver alloy.

In a second aspect, embodiments of the present invention further provide a display device, where the display device includes the PM display panel provided in any embodiment of the present invention.

In the prior art, two driving signals are respectively applied to an anode and a cathode of a light-emitting diode, so that the light-emitting diode is sequentially lightened line by line, but the problem of mutual interference between adjacent sub-pixel points in the same line exists. According to the technical scheme of the embodiment, the thin film transistor is introduced into the PM display panel, the first driving signal line is connected to the grid electrode of the thin film transistor and used for controlling the on/off of the switch of the light emitting diode, the thin film transistor is arranged on each light emitting diode of the PM display panel, and each light emitting diode and the thin film transistor connected with the light emitting diode can form a sub-pixel. The light-emitting diodes can be independently controlled to be turned on/off, pulses are circularly applied to the first driving signal line of each row, the display of all sub-pixels in one row is realized, forward voltage is applied to the sub-pixels needing to emit light, and reverse voltage is applied to the sub-pixels not needing to emit light to enable the sub-pixels not to emit light, so that the mutual crosstalk between pixel points (sub-pixels) in non-gating can be effectively overcome, and the imaging quality is improved. More light-emitting diodes can be arranged on the PM display panel, and the problem that the number of pixel points on the same line is limited can be effectively solved.

Drawings

Fig. 1 is a schematic structural diagram of a PM display panel according to an embodiment of the present invention;

FIG. 2 is a schematic structural diagram of another PM display panel according to an embodiment of the present invention;

fig. 3 is a schematic cross-sectional view of a PM display panel according to an embodiment of the present invention;

fig. 4 is a schematic diagram 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.

Fig. 1 is a schematic structural diagram of a PM display panel according to an embodiment of the present invention, and referring to fig. 1, the embodiment of the present invention provides a PM display panel, which can be suitably applied to a large-sized high-resolution panel, the PM display panel includes a display area and a non-display area, and the display panel further includes a plurality of first driving signal lines 101, a plurality of second driving signal lines 102, a plurality of thin film transistors 104, and a plurality of light emitting diodes 105; the thin film transistors 104 and the light emitting diodes 105 are positioned in the display area and arranged in an array;

the grid of each row of thin film transistors 104 is connected with a first driving signal line 101; the first pole of each row of thin film transistors 104 is connected with a second driving signal line 102; the second pole of a TFT 104 is connected to the first pole of a LED 105, and the first poles of the LEDs 105 connected to the TFTs 104 in the same row are connected to each other.

The thin film transistor 104 may be an oxide thin film transistor, an amorphous silicon thin film transistor, a low temperature polysilicon thin film transistor, or an organic thin film transistor. The thin film transistor 104 only functions as on/off, and when the thin film transistor 104 is turned on, a voltage is output from the source thereof, and the level of the output voltage is determined by a driving circuit connected to the second driving signal line 102.

The grid of each row of thin film transistors 104 is connected with a first driving signal line 101, the first driving signal line 101 may be a row scanning electrode, also called a grid bus, and is connected with the grid of the thin film transistor 104 in each sub-pixel in a row of sub-pixels to control the on/off of the light emitting diode 105; the first electrode of each row of the thin film transistors 104 is connected to a second driving signal line 102, and the second driving signal line 102 may be a row scanning electrode connected to the thin film transistors 104 in each sub-pixel in a row of the sub-pixels, for example, connected to the drain of the thin film transistors 104 in each sub-pixel. The row electrodes of the PM display panel are common and the column electrodes are also common, the display area being caused to emit light by scan control of the row and column electrodes.

The first driving signal line 101 is connected to the gate of each row of the tft 104 for providing a gate voltage to the connected tft 104, the second driving signal line 102 is connected to the first electrode of each column of the tft 104 for providing a display signal corresponding to the brightness, when the gate voltage is greater than the threshold voltage of the tft 104, the tft 104 enters a conducting state, and since the second electrode of the tft 104 is connected to the first electrode of a led 105, the tft 104 transmits the display signal provided by the second driving signal line 102 to the first electrode of the led 105, the led 105 can be controlled to conduct and emit light, thereby realizing light emitting display. When the voltage supplied to the gate of the thin film transistor 104 by the first driving signal line 101 is less than the threshold voltage, the thin film transistor 104 enters an off state. Cross talk to adjacent leds 105 is reduced. When the second driving signal line provides an off voltage, for example, a negative voltage, and transmits the off voltage to the first electrode of the light emitting diode 105, the light emitting diode 105 is turned off, and the corresponding light emitting diode 105 does not emit light any more. It should be noted that the first pole of the thin film transistor 104 may be a drain electrode and the second pole of the thin film transistor 104 may be a source electrode, or the first pole of the thin film transistor 104 may be a source electrode and the second pole of the thin film transistor 104 may be a drain electrode; the first pole of the light emitting diode 105 may be an anode and the second pole of the light emitting diode 105 may be a cathode.

Fig. 2 is a schematic structural diagram of another PM display panel according to an embodiment of the present invention, and referring to fig. 2, optionally, the second pole of each of the light emitting diodes 105 is grounded. Optionally, the PM display panel further includes a driving chip, the driving chip is connected to the first driving signal line 101 and the second driving signal line 102, and the second pole of each light emitting diode 105 is not grounded through the driving chip.

The PM display panel is an OLED display panel driven passively to emit light, and generally, a driving chip supplies power to light emitting pixels in a display area, and the driving chip is connected to a first driving signal line 101 and a second driving signal line 102, so that the purpose of displaying an image is achieved by scanning electrodes of the display area line by line.

The second poles of the light emitting diodes 105 are grounded, the second poles of the light emitting diodes 105 are not grounded through the driving chip, the cathodes of the light emitting diodes 105 are directly grounded, cathode currents do not need to flow through the driving chip, and the problem that line resistance between the first driving signal line 101 and the driving chip generates heat due to overlarge cathode currents can be solved. A first driving signal provided by a driving chip on the display panel of the present invention is applied to the gate of the thin film transistor 104 through the first driving signal line 101, and a second driving signal provided by the driving chip is applied to the first pole of the thin film transistor 104 through the second driving signal line 102. Compared with the prior art, for a light emitting diode, two driving signals provided by the driving chip are respectively applied to the anode and the cathode of the light emitting diode, and the signal line of the driving signal provided to the cathode of the light emitting diode needs to be connected with the common connection end and then connected to the driving chip through the common connection end. The driving of the led 105 in the PM display panel usually requires a large driving signal, and the cathode current of the led 105 is too large, which causes a problem of heat generation of the line resistance between the common connection terminal and the driving chip. The driving signal provided to the gate of the thin film transistor 104 in the present invention can be reduced, and the cathode current of the light emitting diode 105 can be directly grounded without passing through the driving chip by the design of the PM display panel in combination with the thin film transistor 104. The problem that the line resistance between the common connecting end and the driving chip generates heat due to overlarge current of the conventional cathode can be solved, more light emitting diodes 105 can be arranged on the display panel, and the design of high PPI and application to a large display panel is easy to realize.

With continued reference to fig. 2, optionally, the display panel further includes a plurality of third driving signal lines 103;

the second pole of each row of light emitting diodes 105 is connected with a third driving signal line 103; each third driving signal line 103 is grounded.

With continued reference to fig. 2, optionally, the third driving signal lines 103 are connected to each other and then grounded.

The second pole of each row of the light emitting diodes 105 is connected with one third driving signal line 103, and the third driving signal lines 103 are connected with each other and then grounded, so that the display panel has the characteristics of simple structure, few leads and the like.

With continued reference to fig. 2, optionally, the third driving signal lines 103 are connected to each other and then connected to the frame of the display panel.

After the third driving signal lines 103 are connected to each other, a large number of light emitting diodes 105 can be disposed on the frame connected to the display panel, and the current flowing through the light emitting diodes 105 can be effectively conducted to the ground.

Fig. 3 is a schematic cross-sectional structure diagram of a PM display panel provided in an embodiment of the present invention, and referring to fig. 3, optionally, the display panel provided in the embodiment of the present invention includes:

a substrate 201;

a thin film transistor layer, a first metal layer and a pixel defining layer 211 which are sequentially positioned on the substrate 201;

wherein the thin film transistor layer forms a thin film transistor; the first metal layer comprises a plurality of first electrodes 210, and a row of thin film transistors is connected with one first electrode 210; the pixel defining layer 211 is provided with openings, and the pixel defining layer 211 includes a plurality of openings exposing a portion of one of the first electrodes 210.

The substrate 201 may be made of glass, polyimide, or the like. The display panel may further include a barrier layer 202, and the material of the barrier layer 202 may be silicon nitride, silicon oxide, or the like. The thin film transistor layer may include an active layer 203, a semiconductor layer including a source region 204a, a drain region 204b, a gate dielectric layer 205, and a gate electrode 206. The active layer 203 may be made of amorphous silicon, polysilicon, indium gallium zinc oxide, organic semiconductor material, or the like. Indium gallium zinc oxide is a novel semiconductor material and has higher electron mobility than amorphous silicon. The indium gallium zinc oxide is used as a channel material in the high-performance thin film transistor, so that the resolution of the display panel is improved. The source region 204a and the drain region 204b may be doped N/P-type silicon, or copper, gold, etc. The gate 206 may be formed of ito, metal, or the like. The gate dielectric layer 205 may be silicon nitride or silicon oxide. The gate dielectric layer 205 may insulate the source electrode 204a, the drain electrode 204b, and the gate electrode 206 from each other.

The display panel further includes an interlayer dielectric layer 207 and a planarization layer 208. The interlayer dielectric layer 207 is used for buffering the thin film transistor layer and the first electrode 210, and may be made of silicon nitride, silicon oxide, or polymethyl methacrylate. The planarization layer 208 may be such that the thin-film-transistor layer is flush on top. The display panel further includes a drain electrode 209, and the drain electrode 209 may be made of metal, such as gold, copper, or the like.

The pixel defining layer 211 has a plurality of openings formed therein, a light emitting function layer is disposed in the openings, and the pixel defining layer 211 includes a plurality of openings exposing a portion of one of the first electrodes 210, and the openings may correspond to a portion of the stacked first electrodes 210.

With continued reference to fig. 3, optionally, the PM display panel further includes a light emitting function layer and a second electrode 213 disposed on a side of the first electrode 210 away from the substrate 201; the light emitting function layer is disposed in the opening and between the first electrode 210 and the second electrode 213.

The light emitting function layer is located between the first electrode 210 and the second electrode 213, and may be stacked, and the light emitting function layer may be a hole injection layer 212a, a hole transport layer 212b, a light emitting layer 212c, an electron transport layer 212d, and an electron injection layer 212 e.

With continued reference to fig. 3, optionally, the material of the first electrode 210 includes aluminum and the material of the second electrode 213 includes ITO, magnesium silver alloy.

Among them, Indium Tin Oxide (ITO) is an N-type semiconductor material, and has high conductivity, high visible light transmittance, high mechanical hardness, and good chemical stability. The first electrode 210 is typically a reflective electrode and may be made of aluminum, the second electrode 213 is typically a transparent electrode or a semitransparent electrode, the transparent electrode may be made of ITO, and the semitransparent electrode may be made of magnesium-silver alloy.

The thin film transistor is a switching device that only functions to be turned on or off, and the turning on and off of each sub-pixel on the display panel is individually controlled by the thin film transistor. The first electrode 210 may be a row electrode, i.e., a scan electrode, also called a gate bus, connected to the gate of the thin film transistor in each sub-pixel; the second electrode 213 may be a column electrode, i.e. a signal electrode, also called a drain bus, connected to the drain of the tft in each sub-pixel.

Fig. 4 is a schematic diagram of a display device according to an embodiment of the present invention, and referring to fig. 4, a display device including a PM display panel according to any embodiment of the present invention is further provided.

Since the display device includes the PM display panel provided in any embodiment of the present invention, the beneficial effects of the display device and the PM display panel are the same, and are not described herein again.

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 described 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

1. The PM display panel is characterized by comprising a display area and a non-display area, and further comprising a plurality of first driving signal lines, a plurality of second driving signal lines, a plurality of thin film transistors and a plurality of light emitting diodes; the thin film transistors and the light emitting diodes are positioned in the display area and are arranged in an array;

2. A PM display panel as claimed in claim 1, characterized in that the second pole of each of the light emitting diodes is connected to ground.

3. The PM display panel according to claim 2, further comprising a driving chip, wherein the driving chip is connected to the first driving signal line and the second driving signal line, and the second electrode of each of the light emitting diodes is not grounded through the driving chip.

4. The PM display panel according to claim 2, wherein the display panel further comprises a plurality of third driving signal lines;

5. The PM display panel of claim 4, wherein each of the third driving signal lines is connected to each other and then grounded.

6. The PM display panel of claim 4, wherein each of the third driving signal lines is connected to a frame of the display panel.

7. The PM display panel of claim 1, wherein the display panel comprises:

a substrate;

8. The PM display panel according to claim 7, further comprising a light-emitting functional layer and a second electrode provided on a side of the first electrode away from the substrate; the light emitting function layer is disposed in the opening and between the first electrode and the second electrode.

9. The PM display panel of claim 8, wherein the material of the first electrode comprises aluminum and the material of the second electrode comprises ITO, magnesium-silver alloy.

10. A display device comprising the PM display panel according to any one of claims 1 to 9.