Pixel structure

This application claims the priority benefit of Taiwan application serial no. 107124819, filed on Jul. 18, 2018. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of this specification.

The disclosure relates to a pixel structure; more particularly, the disclosure relates to a light emitting diode (LED) pixel structure having a micro LED device.

A micro LED display characterized by the advantages of high brightness, high contrast, wide viewing angle, long service life, and low power consumption has become the focus of future display technology development. The technology of directly transporting the micro LED to a driving back plate is called a mass transfer process which is characterized by following difficulties. First, the size of the micro LED is extremely small (about 5 μm to 10 μm), thus requiring more refined operation techniques. In addition, hundreds of thousands or millions of the micro LEDs are required to form a panel, and one single transportation requires the movement of tens of thousands or even hundreds of thousands of the micro LEDs. During the mass transfer process, the micro LEDs and a thin film transistor (TFT) matrix may be bonded through performing a stamping process.

With reference to FIG. 1 , which depicts a conventional micro LED display panel, when the stamping process is performed on a display panel 100 , the stamping force cannot be effectively and evenly distributed onto the display panel 100 ; therefore, the stamping force applied to the display panel 100 may be different in strength, so that the luminance of the micro LEDs is not uniform as well. In case that the entire panel does not receive the even force, for instance, a region 101 located at a relatively central position of the display panel 100 receives a relatively strong stamping force, so that the micro LEDs may generate relatively greater luminance when the micro LEDs subsequently emit light. By contrast, the stamping force applied to regions outside the region 101 is relatively weak, so that the micro LEDs may generate relatively lower luminance when the micro LEDs subsequently emit light, thus resulting in an issue of uneven overall luminance of the display panel 100 .

The disclosure provides a pixel structure which may detect a stamping force through a detection capacitor and thereby adjust a driving electric signal provided to a micro LED.

In an embodiment of the disclosure, a pixel structure includes a first TFT, a conductive layer, an adhesive layer, an LED, and a detection conductive layer. The first TFT has a first terminal coupled to the conductive layer and is configured to transmit display data to the conductive layer. The adhesive layer is disposed on the conductive layer. The LED is disposed on the adhesive layer. The detection conductive layer is disposed on the adhesive layer, and the detection conductive layer, the adhesive layer, and the conductive layer constitute the detection capacitor. Here, a thickness of the detection conductive layer is equal to or slightly greater than a height of the LED.

According to an embodiment, when a stamping process is performed on the pixel structure, an upper surface of the LED and an upper surface of the detection conductive layer together receive the same stamping force.

According to an embodiment, the pixel structure further includes a second TFT, a control terminal of the second TFT is coupled to the conductive layer, a first terminal of the second TFT receives a reference voltage, and a second terminal of the second TFT is coupled to the LED.

According to an embodiment, a control terminal of the first TFT in the pixel structure receives a scan signal. The detection conductive layer receives a detection signal. Here, in a first time period, the first TFT is switched on according to the scan signal and transmits the display data to the control terminal of the second TFT, and the detection conductive layer simultaneously receives the detection signal at a first voltage level. In a second time period after the first time period, the first TFT is switched off according to the scan signal, and the detection conductive layer simultaneously receives the detection signal at a second voltage level. Here, the first voltage level is different from the second voltage level.

According to an embodiment, the scan signal and the detection signal in the pixel structure are the same signal.

According to an embodiment, in the pixel structure, when the first TFT and the second TFT are both p-type TFTs, the first voltage level is lower than the second voltage level, and the reference voltage is a first power voltage.

According to an embodiment, in the pixel structure, when the first TFT and the second TFT are both n-type TFTs, the first voltage level is higher than the second voltage level, and the reference voltage is a second power voltage.

According to an embodiment, the detection conductive layer of the pixel structure is coupled to the first terminal of the second TFT.

According to an embodiment, a second terminal of the first TFT in the pixel structure receives an initial voltage or the display data. When the first TFT is switched on, the first TFT sequentially receives and transmits the initial voltage and the display data to the control terminal of the second TFT.

According to an embodiment, the pixel structure further includes a third TFT. One terminal of the third TFT receives the initial voltage, and the other terminal of the third TFT is coupled to the control terminal of the second TFT. The third TFT is controlled by a pre-scan signal and is thus switched on or off.

According to an embodiment, the pixel structure further includes a storage capacitor coupled between the control terminal and the first terminal of the second TFT.

According to an embodiment, in the pixel structure, the second TFT generates a driving current to drive the LED, and a capacitance of the driving current and a capacitance of the detection capacitor are negatively correlated.

In view of the above, the detection conductive layer whose height is not lower than that of the LED is configured to receive a pressure exerted during the stamping process, and the value of the capacitance of the detection capacitor constituted by the detection conductive layer, the adhesive layer, and the conductive layer is adjusted according to the pressure received by the detection conductive layer. Besides, the amount of the driving current driving the LED is adjusted according to the capacitance of the detection capacitor, so as to better bring the luminance of the LEDs in the panel into uniformity and improve display quality.

To make the above features and advantages provided in one or more of the embodiments more comprehensible, several embodiments accompanied with drawings are described in detail as follows.

The accompanying drawings are included to provide a further understanding of the disclosure, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the disclosure and, together with the description, serve to explain the principles described herein.

FIG. 1 is a schematic view of a conventional micro LED display panel.

FIG. 2 is a schematic cross-sectional view of a pixel structure according to an embodiment of the invention.

FIG. 3A is a schematic view of a circuitry of the pixel structure depicted in FIG. 2 .

FIG. 3B is a waveform of the driving signal depicted in FIG. 3A .

FIG. 4A is a schematic view of a circuitry of the pixel structure depicted in FIG. 3A according to another embodiment of the disclosure.

FIG. 4B is a waveform of the driving signal depicted in FIG. 4A .

FIG. 5A is a schematic view of a circuitry of a pixel structure according to another embodiment of the disclosure.

FIG. 5B is a waveform of the driving signal depicted in FIG. 5A .

FIG. 6A is a schematic view of a circuitry of the pixel structure depicted in FIG. 5A according to another embodiment of the disclosure.

FIG. 6B is a waveform of the driving signal depicted in FIG. 6A .

FIG. 7A is a schematic view of a circuitry of the pixel structure depicted in FIG. 3A according to a complementary embodiment of the disclosure.

FIG. 7B is a waveform of the driving signal depicted in FIG. 7A .

FIG. 8A is a schematic view of a circuitry of the pixel structure depicted in FIG. 7A according to another embodiment of the disclosure.

FIG. 8B is a waveform of the driving signal depicted in FIG. 8A .

FIG. 9A is a schematic view of a circuitry of the pixel structure depicted in FIG. 5A according to a complementary embodiment of the disclosure.

FIG. 9B is a waveform of the driving signal depicted in FIG. 9A .

FIG. 10A is a schematic view of a circuitry of the pixel structure depicted in FIG. 9A according to another embodiment of the disclosure.

FIG. 10B is a waveform of the driving signal depicted in FIG. 10A .

With reference to FIG. 2 , which is a schematic cross-sectional view of a pixel structure according to an embodiment of the disclosure, a pixel structure 200 includes a first insulating layer IOBP, a second insulating layer ILD, a third insulating layer GI, a first TFT T 1 , a conductive layer M 3 , an adhesive layer 201 , a micro LED μLED, and a detection conductive layer MD. In the present embodiment, the first TFT T 1 is disposed in multiple insulating layers (i.e., the first insulating layer IOBP, the second insulating layer ILD, and the third insulating layer GI), and the conductive layer M 3 is disposed on and covers the first insulating layer IOBP. One terminal (source or drain) of the first TFT T 1 is coupled to the conductive layer M 3 through a conductive via VIA. Besides, the adhesive layer 201 is disposed above the conductive layer M 3 , and the detection conductive layer MD and the micro LED μLED are disposed above the adhesive layer 201 . Here, there is an overlapping region among the detection conductive layer MD, the adhesive layer 201 and the conductive layer M 3 . Note that the height of the detection conductive layer MD may be slightly greater than or equal to the height of the micro LED μLED.

A detection capacitor C DET may be formed in the overlapping region among the detection conductive layer MD, the adhesive layer 201 , and the conductive layer M 3 . Besides, the first TFT T 1 has a gate GE (corresponding to a control terminal) as well as a source (drain) and a drain (source) respectively formed by p-type heavily doped regions PA 1 and PA 2 . A channel CN is formed between the p-type heavily doped regions PA 1 and PA 2 . Here, the source or drain of the first TFT T 1 (corresponding to a first terminal) is coupled to the conductive layer M 3 through the conductive via VIA and may be configured to transmit display data DATA.

As provided above, when a stamping process in a mass transfer process is performed to exert a stamping force F to the pixel structure 200 , an upper surface of the micro LED μLED and an upper surface of the detection conductive layer MD may together receive approximately the same stamping force F, whereby a distance d 1 between the detection conductive layer MD and the conductive layer M 3 is changed (e.g., decreased). When the received stamping force F is relatively strong, the distance d 1 is relatively short, and the capacitance of the detection capacitor C DET is relatively large according to the operating principle of a parallel-plate capacitor. By contrast, when the received stamping force F is relatively weak, the distance d 1 is relatively long, and the capacitance of the detection capacitor C DET is relatively small according to the operating principle of the parallel-plate capacitor. Thereby, the value of the capacitance of the detection capacitor C DET may respond to the strength of the stamping force F. In the embodiment, according to the value of the capacitance of the detection capacitor C DET , the value of the driving electric signal of the micro LED μLED may be adjusted, so as to improve the uniformity of the luminance of the micro LED μLED.

The schematic view of an equivalent circuit of the pixel structure 200 is elaborated hereinafter. Please refer to FIG. 2 and FIG. 3A . FIG. 3A is a schematic view of a circuitry of the pixel structure depicted in FIG. 2 . In the present embodiment, the pixel structure 300 includes a first TFT TP 1 , a second TFT TP 2 , the micro LED μLED, the detection capacitor C DET , and a storage capacitor C ST . The first TFT TP 1 has a second terminal receiving the display data DATA, a control terminal receiving a scan signal S[N], and a first terminal coupled to the conductive layer (e.g., the conductive layer M 3 depicted in FIG. 2 ), and the first TFT TP 1 may be configured to transmit the display data DATA to the conductive layer. The second TFT TP 2 has a control terminal coupled to the conductive layer, a first terminal receiving a reference voltage OVDD, and a second terminal coupled to the micro LED μLED. The reference voltage OVDD is a first power voltage, and first power voltage is a power voltage, for instance. A second terminal of the detection capacitor C DET receives a detection signal DET[N], and the first terminal of the detection capacitor C DET is coupled to the first terminal of the first TFT TP 1 . One terminal of the storage capacitor C ST is coupled to the first terminal of the second TFT TP 2 , and the other terminal of the storage capacitor C ST is coupled to the control terminal of the second TFT TP 2 . An anode terminal of the micro LED μLED is coupled to the second terminal of the second TFT TP 2 , and a cathode terminal of the micro LED μLED receives a reference voltage OVSS, wherein the reference voltage OVSS is a second power voltage, and the second power voltage is a ground voltage, for instance.

Detailed circuit operations are explained hereinafter. Please refer to FIG. 3A and FIG. 3B . FIG. 3B is a waveform of the driving signal depicted in FIG. 3A . In a first time period Ta, the first TFT TP 1 in the pixel structure 300 is switched on according to the scan signal S[N] at a low voltage level V L1 (the first voltage level) and transmits the display data DATA to the control terminal of the second TFT TP 2 . At the same time, the second terminal of the detection capacitor C DET receives the detection signal DET[N] at a low voltage level V L2 (the second voltage level); here, the voltage of a node signal A is substantially the same as the voltage of the display data DATA. In a second time period Tb after the first time period Ta, the first TFT TP 1 is switched off according to the scan signal S[N] whose transient state is a high voltage level V H1 (the third voltage level). The second terminal of the detection capacitor C DET receives the detection signal DET[N] whose transient state is a high voltage level V H2 (the fourth voltage level). Here, the time point at which the detection signal DET[N] has the transient state from the low voltage level V L2 to the high voltage level V H2 may be the same as or slightly later than the time point at which the scan signal S[N] has the transient state from the low voltage level V L1 to the high voltage level V H1 , which should not be construed as a limitation in the disclosure. At this time, the voltage of the node signal A may be expressed as a mathematical formula (1):

DATA + ( V H ⁢ ⁢ 2 - V L ⁢ ⁢ 2 ) ⁢ ⁢ C DET C ST + C DET ( 1 )

The second TFT TP 2 may generate a driving current I μLED according to the voltage of the node signal A and drive the micro LED μLED through the driving current I μLED , so that the micro LED μLED emits light.

In the present embodiment, the TFT generates the driving current I μLED to drive the micro LED μLED, and the driving current I μLED may be expressed as a mathematical formula (2) below. Here, k is a channel constant, and, V TH_TP2 is a threshold voltage of the second TFT TP 2 . Detailed explanation will be provided hereinafter:

I μ ⁢ ⁢ LED = 1 2 ⁢ k ⁡ [ OVDD - DATA - ( V H ⁢ ⁢ 2 - V L ⁢ ⁢ 2 ) ⁢ ⁢ C DET C ST + C DET -  V TH ⁢ ⁢ _ ⁢ ⁢ TP ⁢ ⁢ 2  ] 2 ( 2 )

From the mathematical formula (2), it can be learned that the capacitance of the driving current I μLED and the capacitance of the detection capacitor C DET are negatively correlated; that is, the greater the capacitance of the detection capacitor C DET , the less the driving current I μLED generated by the second TFT TP 2 . On the contrary, the less the capacitance of the detection capacitor C DET , the greater the driving current I μLED generated by the second TFT TP 2 . To be specific, with reference to FIG. 1 , FIG. 2 , FIG. 3A , and the mathematical formula (2), it can be known that when the stamping process is performed, and the stress cannot be evenly distributed, the capacitance of the detection capacitor C DET in regions receiving a relatively large stamping force may be relatively large, and the voltage difference between the source and the gate of the second TFT is reduced to a greater extent, so that the driving current I μLED driving the micro LED μLED is reduced to a greater extent, and that the luminance of the micro LED μLED is reduced to a greater extent. The capacitance of the detection capacitor C DET in regions receiving a relatively small stamping force may be relatively small, and the voltage difference between the source and the gate of the second TFT is reduced to a less extent, so that the driving current I μLED driving the micro LED μLED is reduced to a less extent, and that the luminance of the micro LED μLED is reduced to a less extent. As such, the uniformity of the overall luminance of the micro LED μLED may be enhanced, and the issue of uneven luminance caused by the uneven distribution of the stamping force may be solved.

Please refer to FIG. 4A and FIG. 4B . FIG. 4A is a schematic view of a circuitry of the pixel structure depicted in FIG. 3A according to another embodiment of the disclosure. FIG. 4B is a waveform of the driving signal depicted in FIG. 4A . The difference between the embodiment depicted in FIG. 3A and the present embodiment lies in that the first voltage level is designed to be the same as the second voltage level in the present embodiment, and the third voltage level is designed to be the same as the fourth voltage level in the present embodiment. Besides, in the present embodiment, the scan signal S[N] and the detection signal DET[N] may be combined as one signal. Hence, in the pixel structure 400 provided in the present embodiment, the control terminal of the first TFT TP 1 and the detection capacitor C DET together receive the scan signal S[N], so as to complete the driving operation of the pixel structure.

The manner in which the pixel structure 400 operates is similar to the manner in which the pixel structure 300 operates and therefore will not be further explained.

FIG. 5A is a schematic view of a circuitry of a pixel structure according to another embodiment of the disclosure. FIG. 5B is a waveform of the driving signal depicted in FIG. 5A . The pixel structure 500 includes the first TFT TP 1 , the second TFT TP 2 , a third TFT TP 3 , the micro LED μLED, and the detection capacitor C DET . The first TFT TP 1 has the second terminal receiving the display data DATA, the control terminal receiving the scan signal S[N], and the first terminal coupled to the conductive layer (e.g., the conductive layer M 3 depicted in FIG. 2 ), and the first TFT TP 1 may be configured to transmit the display data DATA to the conductive layer. The second TFT TP 2 has the control terminal coupled to the conductive layer, the first terminal receiving the reference voltage OVDD, and the second terminal coupled to the micro LED μLED. One terminal of the third TFT TP 3 receives an initial voltage V INT , and the other terminal of the third TFT TP 3 is coupled to the control terminal of the second TFT TP 2 . The third TFT TP 3 is controlled by a pre-scan signal S[N−1] and is thus switched on or off. Here, the initial voltage V INT may be at a high voltage level. The detection capacitor C DET is coupled between the first terminal and the control terminal of the second TFT TP 2 and is coupled to the third TFT TP 3 . The anode terminal of the micro LED μLED is coupled to the second terminal of the second TFT TP 2 , and the cathode terminal of the micro LED μLED receives the reference voltage OVSS.

As to the detailed operations of the circuit, in the first time period Ta, the third TFT TP 3 in the pixel structure 500 may be switched on according to the pre-scan signal S[N−1] at the low voltage level V L1 and thereby transmit the initial voltage V INT to the control terminal of the second TFT TP 2 in the first time period Ta. At this time, the voltage of the node signal A may be substantially the same as the initial voltage V INT . In the second time period Tb after the first time period Ta, the third TFT TP 3 is switched off according to the pre-scan signal S[N−1] at the high voltage level V H1 , and the first TFT TP 1 is switched on according to the scan signal S[N] at the low voltage level V L1 . The first TFT TP 1 transmits the display data DATA to the control terminal of the second TFT TP 2 , and at this time the voltage V A (t) of the node signal A may be expressed as a mathematical formula (3):

V A ( t )=DATA+( V INT −DATA) e −t/τ   (3)

Here, τ is a time constant of the capacitor and the resistor and is correlated to an on-resistance of the first TFT TP 1 and the detection capacitor C DET , and t is time.

In a third time period Tc after the second time period Tb, the first TFT TP 1 is switched off according to the scan signal S[N] whose transient state is the high voltage level V H1 , and the second TFT TP 2 generates the driving current I μLED according to the voltage of the node signal A and drives the micro LED μLED through the driving current I μLED .

Please refer to FIG. 6A and FIG. 6B . FIG. 6A is a schematic view of a circuitry of the pixel structure depicted in FIG. 5A according to another embodiment of the disclosure. FIG. 6B is a waveform of the driving signal of the pixel structure depicted in FIG. 6A . The difference between the embodiment shown in FIG. 5A and the present embodiment lies in that the initial voltage V INT and the display data DATA are sequentially transmitted to the first TFT TP 1 in the present embodiment.

The manner in which the pixel structure 600 operates is similar to the manner in which the pixel structure 500 operates and therefore will not be further explained.

FIG. 7A is a schematic view of a circuitry of the pixel structure depicted in FIG. 3A according to a complementary embodiment of the disclosure. The difference between the embodiment shown in FIG. 3A and the present embodiment lies in that the transistor of the present embodiment is complementary to the corresponding transistor in the pixel structure 300 , e.g., an n-type TFT.

As provided above, in the present embodiment, the pixel structure 700 includes a first TFT Tn 1 , a second TFT Tn 2 , the micro LED μLED, the detection capacitor C DET , and the storage capacitor C ST . The first TFT Tn 1 has a second terminal receiving the display data DATA, a control terminal receiving the scan signal S[N], and a first terminal coupled to the conductive layer (e.g., the conductive layer M 3 depicted in FIG. 2 ), and the first TFT Tn 1 may be configured to transmit the display data DATA to the conductive layer. The second TFT Tn 2 has a control terminal coupled to the conductive layer, a first terminal receiving the reference voltage OVSS, and a second terminal coupled to the micro LED μLED. The second terminal of the detection capacitor C DET receives the detection signal DET[N], and the first terminal of the detection capacitor C DET is coupled to the first terminal of the first TFT Tn 1 . One terminal of the storage capacitor C ST is coupled to the first terminal of the second TFT Tn 2 , and the other terminal of the storage capacitor C ST is coupled to the control terminal of the second TFT Tn 2 . One terminal of the micro LED μLED is coupled to the second terminal of the second TFT Tn 2 , and the other terminal of the micro LED μLED receives the reference voltage OVDD.

Detailed circuit operations are explained hereinafter. Please refer to FIG. 7A and FIG. 7B . FIG. 7B is a waveform of the driving signal depicted in FIG. 7A . In the first time period Ta, the first TFT Tn 1 in the pixel structure 700 is switched on according to the scan signal S[N] at the high voltage level V H1 (the first voltage level) and transmits the display data DATA to the control terminal of the second TFT Tn 2 . At the same time, the second terminal of the detection capacitor CDET receives the detection signal DET[N] at the high voltage level V H2 (the second voltage level); here, the voltage of the node signal A is substantially the same as the voltage of the display data DATA. In a second time period Tb after the first time period Ta, the first TFT Tn 1 is switched off according to the scan signal S[N] whose transient state is the low voltage level V L1 (the third voltage level). The second terminal of the detection capacitor CDET receives the detection signal DET[N] whose transient state is the low voltage level V L2 (the fourth voltage level). Here, the time point at which the detection signal DET[N] has the transient state at the low voltage level V L2 may be the same as or slightly later than the time point at which the scan signal S[N] has the transient state at the low voltage level V L1 , which should not be construed as a limitation in the disclosure. At this time, the voltage of the node signal A may be expressed as a mathematical formula (4):

DATA + ( V L ⁢ ⁢ 2 - V H ⁢ ⁢ 2 ) ⁢ ⁢ C DET C ST + C DET ( 4 )

The second TFT Tn 2 may generate the driving current IμLED according to the voltage of the node signal A and drives the micro LED μLED through the driving current IμLED.

Please refer to FIG. 8A and FIG. 8B . FIG. 8A is a schematic view of a circuitry of the pixel structure depicted in FIG. 7A according to another embodiment of the disclosure. FIG. 8B is a waveform of the driving signal depicted in FIG. 8A . The difference between the embodiment depicted in FIG. 8A and the present embodiment lies in that the first voltage level is designed to be the same as the second voltage level in the present embodiment, and the third voltage level is designed to be the same as the fourth voltage level in the present embodiment. Besides, in the present embodiment, the scan signal S[N] and the detection signal DET[N] may be combined as one signal. Hence, in the pixel structure 800 provided in the present embodiment, the control terminal of the first TFT Tn 1 and the detection capacitor C DET together receive the scan signal S[N], so as to complete the driving operation of the pixel structure.

The manner in which the pixel structure 800 operates is similar to the manner in which the pixel structure 700 operates and therefore will not be further explained.

Please refer to FIG. 9A and FIG. 9B . FIG. 9A is a schematic view of a circuitry of the pixel structure depicted in FIG. 5A according to a complementary embodiment of the disclosure. FIG. 9B is a waveform of the driving signal depicted in FIG. 9A . The difference between the embodiment shown in FIG. 5A and the present embodiment lies in that the transistor of the present embodiment is complementary to the corresponding transistor in the pixel structure 500 , e.g., an n-type TFT.

As provided above, the pixel structure 900 includes the first TFT Tn 1 , the second TFT Tn 2 , a third TFT Tn 3 , the micro LED μLED, and the detection capacitor C DET . The first TFT Tn 1 has the second terminal receiving the display data DATA, the control terminal receiving the scan signal S[N], and the first terminal coupled to the conductive layer, and the first TFT Tn 1 may be configured to transmit the display data DATA to the conductive layer. The second TFT Tn 2 has the control terminal coupled to the conductive layer, the first terminal receiving the reference voltage OVSS, and the second terminal coupled to the micro LED μLED. One terminal of the third TFT Tn 3 receives the initial voltage V INT , and the other terminal of the third TFT Tn 3 is coupled to the control terminal of the second TFT Tn 2 , and the third TFT Tn 3 is controlled by a pre-scan signal S[N−1] and is thus switched on or off. Here, the initial voltage V INT may be at a low voltage level. The detection capacitor C DET is coupled to between the first terminal and the control terminal of the second TFT Tn 2 and is coupled to the third TFT Tn 3 . The cathode terminal of the micro LED μLED is coupled to the second terminal of the second TFT Tn 2 , and the anode terminal of the micro LED μLED receives the reference voltage OVDD.

As to the detailed operations of the circuit, in the first time period Ta, the third TFT Tn 3 in the pixel structure 900 may be switched on according to the pre-scan signal S[N−1] at the high voltage level V H1 and thereby transmit the initial voltage V INT to the control terminal of the second TFT TP 2 in the first time period Ta. At this time, the voltage of the node signal A may be substantially the same as the initial voltage V INT . In the second time period Tb after the first time period Ta, the third TFT Tn 3 is switched off according to the pre-scan signal S[N−1] at the low voltage level V L1 , and the first TFT Tn 1 is switched on according to the scan signal S[N] at the high voltage level V H1 . The first TFT Tn 1 transmits the display data DATA to the control terminal of the second TFT Tn 2 , and at this time the voltage V A (t) of the node signal A may be expressed as a mathematical formula (5):

V A ( t )= V INT +(DATA− V INT )(1 −e t/τ )  (5)

In a third time period Tc after the second time period Tb, the first TFT Tn 1 is switched off according to the scan signal S[N] whose transient state is the low voltage level V L1 , and the second TFT Tn 2 generates the driving current I μLED according to the voltage of the node signal A and drives the micro LED μLED through the driving current I μLED .

Please refer to FIG. 10A and FIG. 10B . FIG. 10A is a schematic view of a circuitry of the pixel structure depicted in FIG. 9A according to another embodiment of the disclosure. FIG. 10B is a waveform of the driving signal depicted in FIG. 10A . The difference between the embodiment depicted in FIG. 9A and the present embodiment lies in that the initial voltage V INT and the display data DATA may be combined as one set of signals capable of transmitting the initial voltage V INT and the display data DATA. Hence, in the present embodiment, the first TFT Tn 1 in the pixel structure 1000 is operated with one set of scan signals S[N], and the control of the control terminal of the third TFT Tn 3 is omitted, so as to complete the driving operation of the pixel structure.

The manner in which the pixel structure 1000 operates is similar to the manner in which the pixel structure 900 operates and therefore will not be further explained.

In view of the above, the detection conductive layer whose height is not lower than that of the LED is configured to receive a pressure exerted during the stamping process, and the value of the capacitance of the detection capacitor constituted by the detection conductive layer, the adhesive layer, and the conductive layer is adjusted according to the pressure received by the detection conductive layer. Additionally, the relative value of the capacitance of the detection capacitor may respond to the strength of the stamping force, and the value of the driving electric signal of the micro LED is adjusted according to the correlation between the capacitance of the capacitor and the stamping force, so as to better bring the overall luminance of the micro LED into uniformity, solve the issue of uneven luminance caused by the uneven distribution of the stamping force, and improve display quality.

It will be apparent to those skilled in the art that various modifications and variations can be made to the structure provided herein without departing from the scope or spirit of the disclosure. In view of the foregoing, it is intended that the disclosure provide modifications and variations provided they fall within the scope of the following claims and their equivalents.