TWI726648B - Pixel array substrate and method of fabricating the same - Google Patents

Abstract

A pixel array substrate including a circuit substrate, a plurality of transfer units and a plurality of adhesive patterns is provided. The transfer units are disposed on the circuit substrate and electrically connected to the circuit substrate. Each transfer unit has a supporting structure, a first optical pattern, a second optical pattern, a first light emitting device and a second light emitting device. The supporting structure has a surface, a first groove and a second groove recessed from the surface, and a first bottom surface and a second bottom surface respectively defining the first groove and the second groove. A first distance is provided between the first bottom surface and the circuit substrate. A second distance is provided between the second bottom surface and the circuit substrate and the first distance is lager than the second distance. The first optical pattern and the second optical pattern are respectively disposed in the first groove and the second groove and respectively overlapped with the first light emitting device and the second light emitting device. The adhesive patterns are overlapped with the first grooves of the supporting structures of the transfer units and positioned between the supporting structures and the circuit substrate. A method of fabricating the pixel array substrate is also provided.

Description

Pixel array substrate and manufacturing method thereof

The present invention relates to a display technology, and particularly relates to a pixel array substrate with light-emitting elements and a manufacturing method thereof.

In recent years, when the manufacturing cost of organic light-emitting diode (OLED) display panels is too high and their service life cannot compete with the current mainstream displays, micro LED displays (Micro LED Display) has gradually attracted the investment attention of major technology companies. Miniature light-emitting diode displays have optical performance equivalent to organic light-emitting diode display technology, such as high color saturation, fast response speed and high contrast, and have the advantages of low energy consumption and long material life. However, as far as current technology is concerned, the manufacturing cost of miniature light-emitting diode displays is still higher than that of organic light-emitting diode displays. The main reason is that the manufacturing technology of the micro-light-emitting diode display adopts the method of die transposition to directly transfer the produced micro-light-emitting diode crystal grains to the backplane of the driving circuit, although such a mass transfer technology It has its development advantages in the manufacture of large-size products, but the current related process technology and equipment have bottlenecks to be broken.

For example, a technology that uses a hard electrostatic tip for die transposition has high requirements for the flatness of the bonding surface of the target substrate (such as a circuit backplane) (such as a flatness less than 1 micron). Therefore, it is more difficult to meet the demand for large-area transfer. Another technology that uses soft patterned stamps for die transposition has low requirements for the flatness of the target substrate (for example, less than 5 microns), but its ability to withstand high temperatures and pressures is poor. Therefore, it is not suitable for the transfer bonding process of flip-chip type light emitting diode chips. In other words, to meet the needs of large-area transfer and the applicability of the high temperature and high pressure process has become one of the important issues for related manufacturers when developing grain transfer technology.

The present invention provides a pixel array substrate with better production yield and light extraction efficiency.

The present invention provides a method for manufacturing a pixel array substrate, which has better flexibility in the transfer process.

The pixel array substrate of the present invention includes a circuit substrate, a plurality of transposition units, and a plurality of adhesive patterns. These transposing units are arranged on the circuit substrate and are electrically connected to the circuit substrate. Each of these transposing units includes a supporting structure, a first optical pattern, a second optical pattern, a first light-emitting element, and a second light-emitting element. The supporting structure has a surface, a first groove and a second groove recessed from the surface, and a first bottom surface and a second bottom surface respectively defining the first groove and the second groove. There is a first distance between the first bottom surface and the circuit substrate. There is a second distance between the second bottom surface and the circuit substrate, and the first distance is greater than the second distance. The first optical pattern and the second optical pattern are respectively disposed in the first groove and the second groove. The first light-emitting element and the second light-emitting element are overlapped and arranged on the first optical pattern and the second optical pattern, respectively. The adhesive patterns are overlapped and arranged in the first grooves of the supporting structures of the transposing units, and are located between the supporting structures and the circuit substrate.

The manufacturing method of the pixel array substrate of the present invention includes forming a pattern definition layer on a temporary substrate, forming a support structure on the pattern definition layer, forming a first optical pattern and a second optical pattern on the support structure, and combining the first light-emitting element And the second light-emitting element are transferred to a temporary substrate to form a transposition unit including a supporting structure, a first optical pattern, a second optical pattern, a first light-emitting element and a second light-emitting element, an adhesive pattern is formed on the circuit substrate, and the The transposing unit is transferred to the circuit substrate, so that the adhesive pattern is sandwiched between the first groove of the supporting structure and the circuit substrate. The pattern definition layer has a first recess and a second recess, and the depth of the first recess is smaller than the depth of the second recess. The first recess and the second recess of the support structure covering the pattern definition layer define the first recess and the second recess of the support structure. The first optical pattern and the second optical pattern are disposed in the first groove and the second groove of the supporting structure. The first light-emitting element and the second light-emitting element overlap the first optical pattern and the second optical pattern, respectively. The supporting structure has a first bottom surface and a second bottom surface respectively defining a first groove and a second groove. There is a first distance between the first bottom surface and the circuit substrate. There is a second distance between the second bottom surface and the circuit substrate, and the first distance is greater than the second distance.

Based on the above, in the pixel array substrate and the manufacturing method thereof according to an embodiment of the present invention, the support structure of the transposing unit has two grooves. The distances between the two grooves and the circuit substrate are different from each other, so that the adhesive pattern sandwiched between the support structure and the circuit substrate can be prevented from overflowing during the process of the transposition unit being joined to the circuit substrate, and the transposition is increased. The adhesion stability between the unit and the circuit substrate helps to improve the transfer yield of the transposed unit. On the other hand, in order to improve the light-emitting efficiency of the light-emitting element, two optical patterns overlapping the two light-emitting elements are also provided in the two grooves. In addition, through the arrangement of the optical pattern, the transfer yield of the light-emitting device and the flexibility of the manufacturing process can be effectively improved.

As used herein, "approximately", "approximately", "essentially", or "substantially" includes the stated value and the average value within the acceptable deviation range of the specific value determined by a person of ordinary skill in the art, taking into account all The measurement in question and the specific number of errors associated with the measurement (ie, the limitations of the measurement system). For example, "about" can mean within one or more standard deviations of the stated value, or, for example, within ±30%, ±20%, ±15%, ±10%, ±5%. Furthermore, "about", "approximately", "essentially", or "substantially" used in this article can be based on measurement properties, cutting properties, or other properties to select a more acceptable deviation range or standard deviation. Not one standard deviation applies to all properties.

In the drawings, the thickness of layers, films, panels, regions, etc., are exaggerated for clarity. It should be understood that when an element such as a layer, film, region, or substrate is referred to as being "on" or "connected to" another element, it can be directly on or connected to the other element, or Intermediate elements can also be present. In contrast, when an element is referred to as being "directly on" or "directly connected to" another element, there are no intervening elements. As used herein, "connection" can refer to physical and/or electrical connection. Furthermore, "electrical connection" can mean that there are other components between the two components.

In addition, relative terms such as "lower" or "bottom" and "upper" or "top" can be used herein to describe the relationship between one element and another element, as shown in the figure. It should be understood that relative terms are intended to include different orientations of the device in addition to the orientation shown in the figures. For example, if the device in one figure is turned over, elements described as being on the "lower" side of other elements will be oriented on the "upper" side of the other elements. Therefore, the exemplary term "lower" may include an orientation of "lower" and "upper," depending on the specific orientation of the drawing. Similarly, if the device in one figure is turned over, elements described as "below" or "below" other elements will be oriented "above" the other elements. Thus, the exemplary terms "above" or "below" can include an orientation of above and below.

Reference will now be made in detail to the exemplary embodiments of the present invention, and examples of the exemplary embodiments are illustrated in the accompanying drawings. Whenever possible, the same component symbols are used in the drawings and descriptions to indicate the same or similar parts.

FIG. 1 is a schematic top view of a pixel array substrate according to an embodiment of the invention. FIG. 2 is an enlarged schematic diagram of a transposition unit of the pixel array substrate of FIG. 1. FIG. 3 is a schematic cross-sectional view of the pixel array substrate of FIG. 1. 4A to 4J are schematic cross-sectional views of the manufacturing process of the pixel array substrate of FIG. 3. Fig. 5 is a schematic cross-sectional view of a transfer step of a transposition unit according to another embodiment of the present invention. In particular, for the sake of clarity, FIG. 1 only shows the circuit substrate 100, the support structure 110, the light-emitting element LED and the bonding electrode BE of FIG. 3, and FIG. 2 omits the drawing of the light guide structure layer 120 of FIG. 3 Show.

Please refer to FIGS. 1, 2 and 3, the pixel array substrate 10 includes a circuit substrate 100, a plurality of transposition units TU, and a plurality of adhesion patterns 150. These transposing units TU are arranged on the circuit substrate 100 and are electrically connected to the circuit substrate 100. The adhesive patterns 150 are disposed between the plurality of transposition units TU and the circuit substrate 100, and overlap the transposition units TU, respectively. More specifically, the adhesion patterns 150 can ensure the connection relationship between the transposing units TU and the circuit substrate 100. In this embodiment, the transposed units TU may be arranged in an array on the circuit substrate 100. For example, the transposed units TU may be arranged in multiple columns or rows in the direction X and the direction Y, respectively, but the present invention does not use this Is limited. For example, the circuit substrate 100 may include a substrate, an active device layer, and a plurality of signal traces, but it is not limited to this. For example, the percentage of the vertical projection area of the transposed unit TU on the circuit substrate 100 to the surface area of the circuit substrate 100 may be between 1% and 90%.

The transposition unit TU includes a supporting structure 110, a plurality of light emitting elements LED, and a plurality of bonding electrodes BE. The light emitting elements LED are arranged on the supporting structure 110 and are electrically connected to the bonding electrodes BE. For example, in this embodiment, a plurality of bonding electrodes BE are respectively adjacent to the side 110e1 and the side 110e2 of the supporting structure 110 opposite to each other, and are located on opposite sides of the light-emitting element LEDs, but the present invention does not use this Is limited. In this embodiment, the pixel array substrate 10 further includes a plurality of connection pads BP. These connection pads BP are disposed on the surface 100 s of the circuit substrate 100 and are electrically connected to the circuit substrate 100. It is worth mentioning that the light-emitting element LED of each transposition unit TU is electrically connected to the circuit substrate 100 through the bonding relationship between the bonding electrode BE and the connection pad BP. In other words, the driving signal transmitted by the circuit substrate 100 can be transmitted to the light-emitting element LED through the connection pad BP and the bonding electrode BE, and drive the light-emitting element LED to emit light to achieve a display effect. The manufacturing process of the pixel array substrate 10 shown in FIG. 3 will be exemplarily described below.

Referring to FIG. 4A, first, a pattern definition layer PDL is formed on the temporary substrate 80. The pattern definition layer PDL has a plurality of recesses, which are respectively a first recess PDLr1, a second recess PDLr2, and a third recess PDLr3. The first recess PDLr1 is located between the second recess PDLr2 and the third recess PDLr3. It is worth noting that the first recess PDLr1, the second recess PDLr2, and the third recess PDLr3 of the pattern definition layer PDL respectively have a first depth dt1, a second depth dt2, and a third recess PDLr3 in a direction perpendicular to the temporary substrate 80 (for example, direction Z). The third depth dt3, and the first depth dt1 of the first recess PDLr1 is smaller than the second depth dt2 of the second recess PDLr2 and the third depth dt3 of the third recess PDLr3. In this embodiment, the second depth dt2 of the second recess PDLr2 is substantially equal to the third depth dt3 of the third recess PDLr3, but the invention is not limited thereto. In other embodiments, the third depth dt3 of the third recess PDLr3 may also be between the second depth dt2 of the second recess PDLr2 and the first depth dt1 of the first recess PDLr1.

After the pattern definition layer PDL is formed, a sacrificial layer SL covering the pattern definition layer PDL may also be formed. In this embodiment, the pattern definition layer PDL may further have a fourth recess PDLr4, and the sacrificial layer SL has an opening SLa located in the fourth recess PDLr4. In this embodiment, the material of the sacrificial layer SL may include silicon oxide, silicon nitride, thermosetting resin or light curing resin. Next, as shown in FIG. 4B, a support structure 110 is formed on the sacrificial layer SL. It is worth noting that the portions of the support structure 110 covering the first recess PDLr1, the second recess PDLr2 and the third recess PDLr3 of the pattern definition layer PDL can define the first recess 110r1, the second recess 110r2, and the second recess 110r2 of the support structure 110. Three grooves 110r3. Therefore, the depth relationship of the grooves of the support structure 110 may correspond to the depth relationship of the depressions of the pattern definition layer PDL.

In this embodiment, the grooves of the supporting structure 110 are structurally separated from each other. In other words, the grooves of the supporting structure 110 are not connected to each other. However, the present invention is not limited to this. According to other embodiments, the second groove 110r2 and the third groove 110r3 of the support structure may communicate with each other, and are structurally separated from the first groove 110r1. On the other hand, the part of the support structure 110 covering the fourth recess PDLr4 of the pattern definition layer PDL may be directly connected to the temporary substrate 80 through the opening SLa of the sacrificial layer SL. In this embodiment, the support structure 110 further has a plurality of contact windows 110a overlapping the pattern definition layer PDL. In this embodiment, the material of the support structure 110 may include silicon oxide, silicon nitride, thermal curing resin or light curing resin.

4C, after the support structure 110 is formed, a first optical pattern OP1, a second optical pattern OP2, and a first optical pattern OP1, a second optical pattern OP2, and a third groove 110r3 are formed in the first groove 110r1, the second groove 110r2, and the third groove 110r3 of the support structure 110, respectively. Three optical patterns OP3. It is worth noting that since the depth of the first groove 110r1 of the support structure 110 is smaller than the depth of the second groove 110r2 and the third groove 110r3, the thickness t1 of the first optical pattern OP1 may be smaller than the thickness t2 of the second optical pattern OP2 And the thickness t3 of the third optical pattern OP3. For example, in this embodiment, the optical pattern may protrude from the surface 110s of the supporting structure 110, but it is not limited to this. In other embodiments, the optical pattern can also be selectively aligned with the surface 110s of the support structure 110. The material of the optical pattern may include a heat-curable resin, a light-curable resin, or a light-transmitting material with a Young’s modulus (Young’s modulus) smaller than that of the light-emitting element.

As shown in FIGS. 2 and 4D, after forming the optical pattern, a plurality of bonding electrodes BE and a plurality of connecting electrodes (such as the first connecting electrode CE1, the second connecting electrode CE2, and the third connecting electrode CE3 are formed on the support structure 110). ). The connecting electrodes cover the optical patterns and part of the surface 110s of the support structure 110, respectively. For example, a part of the bonding electrodes BE is disposed between the side 110e1 of the support structure 110 and the second optical pattern OP2 (or the second groove 110r2), and another part of the bonding electrodes BE is disposed on the side of the support structure 110 Between the side 110e2 and the third optical pattern OP3 (or the third groove 110r3). It is worth noting that the bonding electrodes BE overlap the contact windows 110a of the support structure 110 in the normal direction of the surface 110s of the support structure 110, and directly contact the sacrificial layer SL through the contact windows 110a.

The first connection electrode CE1 covers part of the first optical pattern OP1 and extends toward the side 110e1 of the support structure 110 to electrically connect the corresponding bonding electrode BE. The second connection electrode CE2 covers a part of the second optical pattern OP2 and extends toward the side 110e1 of the support structure 110 to electrically connect to the corresponding bonding electrode BE. The third connecting electrode CE3 covers part of the third optical pattern OP3 and extends toward the side 110e2 of the support structure 110 to electrically connect to the corresponding bonding electrode BE. In this embodiment, the step of forming a plurality of connecting electrodes further includes forming a fourth connecting electrode CE4. The fourth connecting electrode CE4 covers part of the first optical pattern OP1, part of the second optical pattern OP2, and part of the third optical pattern OP3 and extends toward the side 110e2 of the support structure 110 to electrically connect the corresponding bonding electrode BE.

After forming the bonding electrode BE and the connecting electrode, as shown in FIGS. 4E and 4F, the light-emitting element LED is transferred to the temporary substrate 80. For example, in the transfer step of the light-emitting element LED, the carrier structure CS1 can be used to adsorb multiple light-emitting element LEDs stored on the source substrate, and move these light-emitting element LEDs to the top of the temporary substrate 80 to be aligned A plurality of optical patterns on the support structure 110. Next, the carrier structure CS1 is moved toward the temporary substrate 80, and the two electrodes of the light-emitting element LED (the electrode E2 and the electrode E1 as shown in FIG. 2) are electrically connected to the part where the connecting electrode overlaps the optical pattern. However, the present invention is not limited to this. In other unillustrated embodiments, the carrier structure can also be the original substrate of the light-emitting element LED, and the light-emitting element LED can be transferred to the temporary substrate 80 by means of laser or mechanical force.

In particular, the material of the optical pattern here can be selected from softer materials. That is, the optical pattern may have buffering characteristics. Accordingly, during the process of bonding the light-emitting element LED to the temporary substrate 80, the light-emitting element LED can be prevented from being damaged due to excessive compression of the carrier structure CS1, which helps to improve the transfer yield of the light-emitting element LED. From another point of view, the transfer process can reduce the specification requirements for the surface flatness of the temporary substrate 80 or the carrier structure CS1, which is helpful for realizing large-area die transfer. In other words, the flexibility of the process for transferring the die (such as the light-emitting device LED) can be increased.

Furthermore, since the optical pattern has a buffering characteristic, the material of the carrier structure CS1 can be made of a harder material, which helps to improve the resistance of the carrier structure CS1 to high temperature and high pressure. On the other hand, since the optical pattern can protrude from the surface 110s of the supporting structure 110, when the light-emitting element LED contacts the optical pattern overlapping it, the light-emitting element LED that is not overlapped with the optical pattern and the temporary substrate 80 remain structurally separated. status. In other words, through the above arrangement of optical patterns, local transfer of multiple crystal grains can be realized.

Referring to FIG. 4G, in this embodiment, the manufacturing method of the pixel array substrate 10 may optionally further include: forming a light guide structure layer 120 on the support structure 110 after the step of transferring the light emitting element LED. It should be noted that the light guide structure layer 120 has a plurality of openings 120n overlapping the first optical pattern OP1, the second optical pattern OP2, and the third optical pattern OP3, and the first light-emitting element LED1, the second light-emitting element LED2, and the The three light-emitting elements LED3 are respectively disposed in the openings 120n of the light guide structure layer 120. This completes the production of the transposition unit TU of this embodiment.

After the production of the transposition unit TU is completed, as shown in FIG. 4H and FIG. 4I, the transposition unit TU is transferred to the circuit board 100. For example, in the transfer step of the transposed unit TU, the carrier structure CS2 can be used to adsorb a plurality of transposed units TU stored on the temporary substrate 80 (as shown in FIG. 4H). In this embodiment, the step of transferring the transposed unit TU may optionally include removing the sacrificial layer SL to separate the support structure 110 of the transposed unit TU from the pattern definition layer PDL. At this time, the transposition unit TU is only connected to the temporary substrate 80 through the part of the support structure 110 located in the fourth recess PDLr4 of the pattern definition layer PDL. In particular, after the carrier structure CS2 touches the light guide structure layer 120 and completes the adsorption of the transposed unit TU, the carrier structure CS2 is moved away from the temporary substrate 80, so that the support structure 110 is located on the pattern definition layer. The part in the fourth recess PDLr4 of the PDL is disconnected, and the transposition unit TU is driven to leave the temporary substrate 80 to complete the extraction of the transposition unit TU. However, the present invention is not limited to this. According to other embodiments, the transposing unit may not have the light guide structure layer 120. As shown in FIG. 5, in the transfer step of the transposed unit, the carrier structure CS2 can also be directly connected to the top surface of the light-emitting element to perform the transfer and bonding of the transposed unit.

Please refer to FIG. 4I, then, move the transposing unit TU to the upper side of the circuit substrate 100, so that the multiple bonding electrodes BE of the transposing unit TU are positioned on the multiple connection pads BP on the circuit substrate 100. In order to stabilize the connection relationship between the transposing unit TU and the circuit substrate 100, before the transposing unit TU is transferred to the circuit substrate 100, an adhesive pattern 150 may be formed on the circuit substrate 100, and the connection pads BP are respectively located at two opposite sides of the adhesive pattern 150. side. Furthermore, when the transposition unit TU is driven by the carrier structure CS2 to complete the alignment of the bonding electrode BE and the connection pad BP, the adhesive pattern 150 overlaps the first surface in the normal direction of the surface 100s of the circuit substrate 100. The optical pattern OP1 does not overlap the second optical pattern OP2 and the third optical pattern OP3, but is not limited to this. In other embodiments, according to different product designs or process conditions, the adhesive pattern 150 may also partially overlap the second optical pattern OP2 and the third optical pattern OP3 in the normal direction of the surface 100s of the circuit substrate 100.

Please refer to FIG. 4I and FIG. 4J. Next, the carrier structure CS2 is moved toward the circuit substrate 100, so that the bonding electrodes BE of the transposition unit TU are electrically connected to the connection pads BP on the circuit substrate 100. It is worth noting that the part of the supporting structure 110 that defines the first optical pattern OP1, the second optical pattern OP2, and the third optical pattern OP3 can also define a fourth groove 110r4, and the fourth groove 110r4 is similar to the aforementioned groove (for example, The first groove 110r1, the second groove 110r2 or the third groove 110r3) are respectively located on opposite sides of the support structure 110.

During the joining process of the transposing unit TU and the circuit substrate 100, the adhesive pattern 150 can define a second recess in the fourth recess 110r4 toward the support structure 110 under the squeezing of the part of the support structure 110 defining the first recess 110r1. Part of the groove 110r2 and the third groove 110r3 flows. Accordingly, the adhesion stability between the transposed unit TU and the circuit substrate 100 can be increased, which helps to improve the transfer yield of the transposed unit TU. From another point of view, since the thickness t2 of the second optical pattern OP2 and the thickness t3 of the third optical pattern OP3 of the transposed unit TU are greater than the thickness t1 of the first optical pattern OP1, the second optical pattern OP2 is located in a part of the bonding electrode Between BE and the adhesive pattern 150 and the third optical pattern OP3 is located between another part of the bonding electrode BE and the adhesive pattern 150. During the bonding process between the transposition unit TU and the circuit substrate 100, the adhesive pattern 150 can be prevented from being caused by the support structure 110. The squeezing and overflow to the connection pad BP and adhere between the bonding electrode BE and the connection pad BP. In other words, through the above-mentioned arrangement relationship of the optical patterns, the bonding yield of the transposition unit TU and the circuit substrate 100 can be effectively improved.

For example, in this embodiment, the joining process of the transposing unit TU and the circuit substrate 100 can be performed by heating and pressing, but it is not limited to this. More specifically, when the bonding electrode BE of the transposing unit TU contacts the connection pad BP on the circuit substrate 100, the carrier structure CS2 can press the connection surface of the bonding electrode BE and the connection pad BP through the light guide structure layer 120. To ensure the effect of electrical bonding. On the other hand, since the material of the light guide structure layer 120 here can be selected from soft materials, such as thermosetting resin or light curing resin. That is, the light guide structure layer 120 may have buffering characteristics. Accordingly, the specification requirements for the surface flatness of the circuit substrate 100 or the carrier structure CS2 in the transfer process can be reduced, which helps to realize the large-area transfer of the transposed unit TU. Furthermore, since the light guide structure layer 120 has a buffering characteristic, the material of the carrier structure CS2 can be made of a harder material, which helps to improve the resistance of the carrier structure CS2 to high temperature and high pressure.

In particular, in this embodiment, the thickness of the connection pad BP can be substantially equal to the depth of the second groove 110r2 or the third groove 110r3, and the material of the connection pad BP can be selected from metal materials, but the present invention Not limited to this. In other embodiments, the material of the connection pad can also be a combination of insulating material and metal material. For example, an insulating material is used as the main body, and then the main body is covered with a metal material to form the connection pad. This can increase the process flexibility of the connection pad and reduce Its production cost. In other embodiments, the thickness of the connection pad may also be slightly larger than the depth of the second groove 110r2 or the third groove 110r3.

At this point, the pixel array substrate 10 of this embodiment is completed. It can be seen from FIGS. 1, 2 and 3 that the pixel array substrate 10 includes a circuit substrate 100, a plurality of transposition units TU, and a plurality of adhesion patterns 150. The transposition unit TU includes a supporting structure 110, a first optical pattern OP1, a second optical pattern OP2, a first light-emitting element LED1, and a second light-emitting element LED2. The support structure 110 has a surface 110s and a first groove 110r1 and a second groove 110r2 recessed from the surface 110s. The first optical pattern OP1 and the second optical pattern OP2 are respectively disposed in the first groove 110r1 and the second groove 110r2. The first light emitting element LED1 and the second light emitting element LED2 are respectively disposed on the first optical pattern OP1 and the second optical pattern OP2.

In this embodiment, the luminous efficiency of the first light-emitting element LED1 may be higher than the luminous efficiency of the second light-emitting element LED2. For example, the first light-emitting element LED1 may be a blue light-emitting diode, and the second light-emitting element LED2 may be a red light-emitting diode or a green light-emitting diode, but it is not limited to this. The thickness t2 of the second optical pattern OP2 in the direction perpendicular to the surface 110s of the support structure 110 (for example, the direction Z) is greater than the thickness t1 of the first optical pattern OP1 in the direction Z (as shown in FIG. 4C). The proportion of light emitted by the two light-emitting elements LED2 in the light-emitting direction (for example, direction Z) is higher than the proportion of light emitted by the first light-emitting element LED1 in the light-emitting direction (for example, direction Z). In other words, the arrangement of two optical patterns with different thicknesses can compensate for the difference in light output efficiency of the two light-emitting elements due to the difference in luminous efficiency.

In this embodiment, the transposition unit TU can also optionally include a third optical pattern OP3 and a third light emitting element LED3, and the support structure 110 further has a third groove 110r3 recessed from the surface 110s. The third optical pattern OP3 is disposed in the third groove 110r3, and the third light-emitting element LED3 is disposed on the third optical pattern OP3. The thickness t3 of the third optical pattern OP3 in a direction perpendicular to the surface 110s of the support structure 110 (for example, the direction Z) is greater than the thickness t1 of the first optical pattern OP1 in the direction Z (as shown in FIG. 4C). That is to say, under the configuration of the thickness relationship of the optical patterns described above, the luminous efficiency of the third light-emitting element LED3 of this embodiment may be lower than that of the first light-emitting element LED1.

It is worth noting that the supporting structure 110 also has a first bottom surface 110b1 and a second bottom surface 110b2 respectively defining the first groove 110r1 and the second groove 110r2. There is a first distance d1 between the first bottom surface 110b1 of the support structure 110 and the surface 100s of the circuit substrate 100, and a second distance d2 exists between the second bottom surface 110b2 of the support structure 110 and the surface 100s of the circuit substrate 100, and the first distance d1 is greater than the second distance d2. In this embodiment, the supporting structure 110 may further have a third bottom surface 110b3 defining the third groove 110r3, and there is a third distance d3 between the third bottom surface 110b3 of the supporting structure 110 and the surface 100s of the circuit substrate 100, and the first The distance d1 is greater than the third distance d3. In other words, the cross-sectional (for example, XZ plane) profile of the portion of the supporting structure 110 overlapping the adhesive pattern 150 is stepped. Accordingly, the controllability of the adhesive pattern 150 during flow can be improved, which helps increase the adhesion stability of the transposed unit TU and the circuit substrate 100. On the other hand, through the second groove 110r2 (or the second optical pattern OP2) provided between a part of the bonding electrode BE and the adhesive pattern 150 and the third groove 110r2 (or the second optical pattern OP2) provided between the other part of the bonding electrode BE and the adhesive pattern 150 The groove 110r3 (or the third optical pattern OP3) can prevent the adhesive pattern 150 from overflowing to the connection pad BP due to the squeezing of the support structure 110 and adhering between the bonding electrode BE and the connection pad BP. In other words, the bonding yield between the transposed unit TU and the circuit substrate 100 can be effectively improved.

It should be noted that, in this embodiment, the number of grooves, optical patterns, and light-emitting element LEDs of the transposing unit TU are exemplarily described by taking three as an example. In other words, the transposition unit TU of this embodiment can constitute one display pixel of the pixel array substrate 10, but the invention is not limited to this. In other embodiments, the number of grooves, optical patterns, and light-emitting element LEDs of the transposing unit can also be adjusted to two according to actual design requirements or process considerations (for example, the transposing unit has only the first groove 110r1 and the second The two grooves 110r2, the first optical pattern OP1, the second optical pattern OP2, the first light-emitting element LED1, and the second light-emitting element LED2) or more than four.

Other embodiments will be listed below to describe the disclosure in detail, wherein the same components will be marked with the same symbols, and the description of the same technical content will be omitted. For the omitted parts, please refer to the foregoing embodiments, and will not be repeated hereafter.

6 is a schematic cross-sectional view of a pixel array substrate according to another embodiment of the invention. Please refer to FIG. 6, the difference between the pixel array substrate 11 of this embodiment and the pixel array substrate 10 of FIG. 3 is that the composition of the pixel array substrate is different. Specifically, the pixel array substrate 11 further includes a plurality of optical patterns OP', and these optical patterns OP' are disposed in the plurality of openings 120n of the light guide structure layer 120 and cover a plurality of light-emitting elements. In this embodiment, the optical pattern OP' may be a color filter pattern (for example, a red filter pattern, a green filter pattern, or a blue filter pattern), and the light-emitting colors of these light-emitting element LEDs are all the same (for example, white). ). However, the present invention is not limited to this. According to other embodiments, the light-emitting color of these light-emitting element LEDs is blue, and the optical pattern OP' may also be a wavelength conversion pattern to convert the blue light emitted by the light-emitting element LED into red light. Green or yellow light. The material of the wavelength conversion pattern may include fluorescent material or quantum dot material. In another embodiment not shown, the material of the optical patterns OP' can also be a transparent resin with a high refractive index, and the light-emitting element LEDs are red light-emitting diodes and green light-emitting diodes. With blue light emitting diodes.

FIG. 7 is a schematic top view of a pixel array substrate according to another embodiment of the present invention. FIG. 8 is an enlarged schematic diagram of the transposition unit of the pixel array substrate of FIG. 7. In particular, for the sake of clarity, the transposition unit TU' of FIG. 7 only depicts the support structure 110A, the light-emitting element LED, and the bonding electrode BE of FIG. 8. Referring to FIGS. 7 and 8, the main difference between the pixel array substrate 12 of this embodiment and the pixel array substrate 10 of FIGS. 1 and 2 lies in the arrangement of bonding electrodes, the arrangement of transposed units, and the arrangement of optical patterns. The configuration method is different. In this embodiment, the first light-emitting element LED1, the second light-emitting element LED2, and the third light-emitting element LED3 of the transposition unit TU' can be used to display red, green, and blue colors, respectively. In other words, the transposing unit TU' can constitute one display pixel of the pixel array substrate 12, but the present invention is not limited to this.

Referring to FIG. 7, the multiple transposition units TU' of this embodiment can be arranged in multiple pixel strings (or pixel rows) along the direction X, such as a first pixel string PR1, a second pixel string PR2, and a second pixel string PR2. The third pixel string PR3 and the fourth pixel string PR4, and the multiple transposition units TU' of the two adjacent pixel strings are all misaligned in the direction Y. For example, any one of the plurality of transposition units TU' arranged in the first pixel string PR1 is staggered in the plurality of transpositions arranged in the second pixel string PR2 perpendicular to the direction X (that is, the direction Y) Any one of the units TU', any one of the plurality of transposed units TU' arranged in the second pixel string PR2 is staggered in the direction Y, and the plurality of transposed units TU' arranged in the third pixel string PR3 Any one of, and so on.

More specifically, the light emitting element LEDs of the two adjacent transposition units TU' arranged along the direction Y are staggered from each other in the direction Y. Accordingly, the light mixing effect of display pixels can be increased. However, the present invention is not limited to this. According to other embodiments, two adjacent transposing units TU' arranged along the direction X may also be misaligned in the direction X. Referring to FIG. 8, in this embodiment, the multiple bonding electrodes BE of the transposing unit TU' are adjacent to the adjacent two sides of the support structure 110A, for example: the side 110e2 and the side 110e3, and the first connection The electrode CE1A, the second connecting electrode CE2A, and the third connecting electrode CE3A each extend toward the side 110e3 of the support structure 110A to be electrically connected to the corresponding bonding electrode BE.

It is worth noting that the transposition unit TU' of this embodiment further includes a fourth optical pattern OP4, and the fourth optical pattern OP4 is set between the adhesive pattern 150A and the bonding electrode BE adjacent to the side 110e3 of the support structure 110A. between. In this embodiment, the configuration (for example, thickness) of the fourth optical pattern OP4 is similar to the third optical pattern OP3 or the second optical pattern OP2. Therefore, for the detailed description, please refer to the relevant paragraphs of the foregoing embodiment, which will not be repeated here. For example, the thickness of the fourth optical pattern OP4 in the direction Z of this embodiment may be equal to the thickness of the third optical pattern OP3 in the direction Z. Therefore, during the joining process of the transposing unit TU' and the circuit substrate 100, the adhesive pattern 150A can be prevented from overflowing to the area between the side 110e3 of the supporting structure 110A and the fourth optical pattern OP4 due to the extrusion of the supporting structure 110A. The bonding electrode BE and the connection pad (not shown) are attached between the bonding electrode BE and the connection pad. In other words, the bonding yield between the transposition unit TU' and the circuit substrate 100 can be effectively improved.

In summary, in the pixel array substrate and the manufacturing method thereof according to an embodiment of the present invention, the support structure of the transposing unit has two grooves. The distances between the two grooves and the circuit substrate are different from each other, so that the adhesive pattern sandwiched between the support structure and the circuit substrate can be prevented from overflowing during the process of the transposition unit being joined to the circuit substrate, and the transposition is increased. The adhesion stability between the unit and the circuit substrate helps to improve the transfer yield of the transposed unit. On the other hand, in order to improve the light extraction efficiency of the light emitting element, two optical patterns overlapping the two light emitting elements are also provided in the two grooves. In addition, through the arrangement of the optical pattern, the transfer yield of the light-emitting device and the flexibility of the manufacturing process can be effectively improved.

10, 11, 12: pixel array substrate 80: Temporary substrate 100: Circuit board 100s, 110s: surface 110, 110A: supporting structure 110a: contact window 110b1, 110b2, 110b3: bottom surface 110e1, 110e2, 110e3: side 110r1, 110r2, 110r3, 110r4: groove 120: Light guide structure layer 120n: opening 150, 150A: Adhesive pattern BE: Bonding electrode BP: connection pad CE1, CE1A, CE2, CE2A, CE3, CE3A, CE4: connecting electrodes CS1, CS2: carrier board structure d1, d2, d3: distance dt1, dt2, dt3: depth E1, E2: Electrode LED, LED1, LED2, LED3: light-emitting element OP1, OP2, OP3, OP4, OP’: optical pattern PDL: Pattern definition layer PDLr1, PDLr2, PDLr3, PDLr4: recessed PR1, PR2, PR3, PR4: pixel string SL: Sacrificial layer SLa: opening t1, t2, t3: thickness TU, TU’: Transposed unit X, Y, Z: direction

FIG. 1 is a schematic top view of a pixel array substrate according to an embodiment of the invention. FIG. 2 is an enlarged schematic diagram of a transposition unit of the pixel array substrate of FIG. 1. FIG. 3 is a schematic cross-sectional view of the pixel array substrate of FIG. 1. 4A to 4J are schematic cross-sectional views of the manufacturing process of the pixel array substrate of FIG. 3. Fig. 5 is a schematic cross-sectional view of a transfer step of a transposition unit according to another embodiment of the present invention. 6 is a schematic cross-sectional view of a pixel array substrate according to another embodiment of the invention. FIG. 7 is a schematic top view of a pixel array substrate according to another embodiment of the present invention. FIG. 8 is an enlarged schematic diagram of the transposition unit of the pixel array substrate of FIG. 7.

10: Pixel array substrate

100: Circuit board

100s, 110s: surface

110: Supporting structure

110b1, 110b2, 110b3: bottom surface

110r1, 110r2, 110r3, 110r4: groove

120: Light guide structure layer

120n: opening

150: Adhesive pattern

BE: Bonding electrode

BP: connection pad

CE1, CE2, CE3: Connect the electrodes

d1, d2, d3: distance

E2: Electrode

LED1, LED2, LED3: light-emitting elements

OP1, OP2, OP3: Optical pattern

X, Z: direction

Claims (22)

A pixel array substrate includes: a circuit substrate; a plurality of transposing units are arranged on the circuit substrate, the transposing units are electrically connected to the circuit substrate, and each includes: a support structure having a surface and a self A first groove and a second groove recessed on the surface, and a first bottom surface and a second bottom surface respectively defining the first groove and the second groove, wherein the first bottom surface and the circuit substrate are There is a first distance between the second bottom surface and the circuit substrate, and the first distance is greater than the second distance; a first optical pattern and a second optical pattern are respectively disposed on the In the first groove and the second groove; and a first light-emitting element and a second light-emitting element, which are respectively arranged in the first optical pattern and the second optical pattern; and a plurality of adhesive patterns, which are arranged in an overlapping manner The plurality of first grooves of the plurality of supporting structures of the transposing units are located between the supporting structures and the circuit substrate. The pixel array substrate according to claim 1, wherein each of the transposing units further includes: a third optical pattern disposed in a third groove of the supporting structure, wherein the supporting structure further defines the third optical pattern A third bottom surface of the groove, a third distance between the third bottom surface and the circuit substrate, and the first distance is greater than the third distance; and A third light-emitting element is arranged on the third optical pattern, wherein the first light-emitting element is located between the second light-emitting element and the third light-emitting element. The pixel array substrate according to claim 2, wherein each of the transposed units further includes: a light guide structure layer disposed on the surface of the support structure, and the light guide structure layer has an overlapped first optical pattern A plurality of openings of the second optical pattern and the third optical pattern, and the first light-emitting element, the second light-emitting element, and the third light-emitting element are respectively disposed in the openings. The pixel array substrate according to claim 3, further comprising: a plurality of color filter patterns disposed in the openings of the light guide structure layer and covering the first light-emitting element, the second light-emitting element, and the first light-emitting element Three light-emitting elements. The pixel array substrate according to claim 3, further comprising: a plurality of wavelength conversion patterns disposed in the openings of the light guide structure layer and covering the first light-emitting element, the second light-emitting element, and the third light-emitting element. Light-emitting element. The pixel array substrate according to claim 2, wherein the support structure further has a fourth groove defined by the first optical pattern, the second optical pattern, and the third optical pattern, and the adhesion patterns Are arranged in the fourth grooves of the supporting structures. The pixel array substrate according to claim 1, wherein each of the transposing units further includes: a plurality of bonding electrodes electrically connected to the first light-emitting element and the second light-emitting element, and is adjacent to at least the supporting structure On both sides, and some of the bonding electrodes Between one of the at least two sides and the second groove. The pixel array substrate according to claim 7, wherein the second optical pattern is located between a part of the bonding electrodes and the adhesion pattern. The pixel array substrate according to claim 1, wherein the luminous efficiency of the first light-emitting element is higher than that of the second light-emitting element. The pixel array substrate according to claim 1, wherein the first light-emitting element is a blue light-emitting diode, and the second light-emitting element is a red light-emitting diode or a green light-emitting diode. The pixel array substrate according to claim 1, wherein the first optical pattern has a first thickness in a direction, the second optical pattern has a second thickness in the direction, and the first optical pattern has a The first thickness is smaller than the second thickness of the second optical pattern. The pixel array substrate according to claim 1, wherein the transposed units are arranged in a first pixel string and a second pixel string adjacent to each other along one direction, and the transposed units form the second pixel string. Any one of a pixel string is misplaced in any one of the transposed units in the direction perpendicular to the direction to form the second pixel string. A method for manufacturing a pixel array substrate includes: forming a pattern definition layer on a temporary substrate, wherein the pattern definition layer has a first recess and a second recess, and the depth of the first recess is smaller than the second recess The depth of; forming a support structure on the pattern definition layer, wherein the support structure covers the first depression and the second depression of the pattern definition layer to define the support structure A first groove and a second groove of the supporting structure; forming a first optical pattern and a second optical pattern on the supporting structure, wherein the first optical pattern and the second optical pattern are disposed on the supporting structure In the first groove and the second groove; a first light-emitting element and a second light-emitting element are transferred to the temporary substrate to form the support structure, the first optical pattern, the second optical pattern, A transposition unit of the first light-emitting element and the second light-emitting element, wherein the first light-emitting element and the second light-emitting element overlap the first optical pattern and the second optical pattern, respectively; formed on a circuit substrate An adhesive pattern; and transferring the transposing unit to the circuit substrate so that the adhesive pattern is sandwiched between the first groove of the supporting structure and the circuit substrate, wherein the supporting structure has the first groove respectively defining the first A first bottom surface and a second bottom surface of the groove and the second groove, a first distance between the first bottom surface and the circuit substrate, and a second distance between the second bottom surface and the circuit substrate , And the first distance is greater than the second distance. The method for manufacturing a pixel array substrate according to claim 13, wherein the first optical pattern and the second optical pattern protrude from a surface of the support structure. The method for manufacturing a pixel array substrate according to claim 13, further comprising: after the step of transferring the first light-emitting element and the second light-emitting element, forming a light guide structure layer on the support structure, wherein the guide The light structure layer has the An optical pattern and a plurality of openings of the second optical pattern, and the first light-emitting element and the second light-emitting element are respectively disposed in the openings. The method for manufacturing a pixel array substrate according to claim 15, further comprising: forming a plurality of wavelength conversion patterns in the openings of the light guide structure layer, wherein the wavelength conversion patterns cover the first light-emitting element and the The second light-emitting element. The method for manufacturing a pixel array substrate according to claim 15, further comprising: forming a plurality of color filter patterns in the openings of the light guide structure layer, wherein the color filter patterns cover the first light-emitting element And the second light-emitting element. The method for manufacturing a pixel array substrate according to claim 15, wherein the transferring step of the transposing unit includes: using a carrier structure to adsorb the light guide structure layer to drive the transposing unit to leave the temporary substrate. The manufacturing method of the pixel array substrate according to claim 13, further comprising: forming a plurality of bonding electrodes on the supporting structure, wherein the bonding electrodes are adjacent to at least two sides of the supporting structure, and the second The optical pattern is located between part of the bonding electrodes and the adhesion pattern. The manufacturing method of the pixel array substrate according to claim 19, further comprising: forming a light guide structure layer on the support structure, wherein the light guide structure layer covers The bonding electrodes have a plurality of openings overlapping the first groove and the second groove, and the first light-emitting element and the second light-emitting element are respectively disposed in the openings. The manufacturing method of the pixel array substrate according to claim 13, further comprising: forming a sacrificial layer after forming the pattern definition layer, wherein the support structure is formed on the sacrificial layer. The method for manufacturing a pixel array substrate according to claim 21, wherein the step of transferring the transposing unit includes removing the sacrificial layer to separate the support structure from the pattern definition layer.

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