Display module, preparation method thereof and display device

Abstract

The application provides a display module, a preparation method thereof and a display device. The display module comprises: a display panel provided with at least two binding areas, each binding area comprising a plurality of conductive parts arranged at intervals; and a circuit board comprising at least two binding parts arranged at intervals, each binding part comprising a plurality of pins arranged at intervals, the plurality of pins of each binding part corresponding to and connected with the plurality of conductive parts of one binding area, the first pre-shrinking ratio being greater than the second pre-shrinking ratio, so that the pre-shrinking amount in the second pre-shrinking direction is smaller than the pre-shrinking amount in the first pre-shrinking direction, the smaller pre-shrinking amount in the second pre-shrinking direction can offset the smaller expansion amount in the second thermal expansion direction, the larger pre-shrinking amount in the first pre-shrinking direction can offset the larger expansion amount in the first thermal expansion direction, and thus after heat pressing and binding, each pin on the circuit board can be accurately aligned and bound with the corresponding conductive part, thereby improving the binding and alignment accuracy of the circuit board.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of display, in particular to a display module, a preparation method thereof and a display device. BACKGROUND

[0002] The existing large-size flexible printed circuit (FPC) mainly has two structures: one is that the binding parts are continuous as a whole without disconnection, and the other is that the binding parts are disconnected between adjacent binding parts, and two binding parts form a "U" shape. For the "U" shaped circuit board, due to the particularity of its structure, after the binding and alignment of the display panel, the alignment offset between the binding flexible circuit board and the display panel is large, and the alignment precision is poor. SUMMARY

[0003] Therefore, the purpose of the present application is to provide a display module, a preparation method thereof and a display device.

[0004] To achieve the above purpose, the first aspect of the present application provides a display module, comprising:

[0005] a display panel, wherein the display panel is provided with at least two binding areas, and each binding area comprises a plurality of conductive parts arranged at intervals;

[0006] a circuit board, wherein the circuit board comprises at least two binding parts arranged at intervals, each binding part comprises a plurality of pins arranged at intervals, and the plurality of pins of each binding part correspond to and are connected to the plurality of conductive parts of a binding area;

[0007] wherein the distance between the first center axis of the first pin of each binding part and the second center axis of the binding part is a first distance, the distance between the third center axis of the first conductive part of the binding area corresponding to the binding part and the fourth center axis of the binding area is a second distance, the first pin is the pin farthest from the second center axis among the plurality of pins, the first conductive part is the conductive part corresponding to the first pin, and the ratio of the difference between the second distance and the first distance to the second distance is a first pre-shrinking ratio;

[0008] the distance between the second center axes of two adjacent binding parts is a third distance, the distance between the fourth center axes of two adjacent binding areas is a fourth distance, and the ratio of the difference between the fourth distance and the third distance to the fourth distance is a second pre-shrinking ratio;

[0009] The first pre-shrinking ratio is greater than the second pre-shrinking ratio.

[0010] The second aspect of the present application provides a preparation method of a display module, comprising:

[0011] The display panel is provided with at least two binding areas, each of the binding areas comprises a plurality of conductive parts arranged at intervals, wherein the distance between the third central axis of the first conductive part of the binding area and the fourth central axis of the binding area is a second distance, and the distance between the fourth central axes of two adjacent binding areas is a fourth distance.

[0012] The first pre-shrinking ratio and the second pre-shrinking ratio of the circuit board are determined, the first pre-shrinking ratio is greater than the second pre-shrinking ratio, and the circuit board comprises at least two binding parts arranged at intervals, each of the binding parts comprises a plurality of pins arranged at intervals.

[0013] Based on the first pre-shrinking ratio, the second pre-shrinking ratio, the second distance and the fourth distance, the size of the circuit board after pre-shrinking is determined to obtain a pre-shrinking circuit board.

[0014] Each of the binding parts of the pre-shrinking circuit board is aligned with a binding area of the display panel, and the binding parts are connected by a hot pressing process, so that the plurality of pins of each of the binding parts correspond to and are connected with the plurality of conductive parts of the binding area.

[0015] The third aspect of the present application provides a display device comprising the display module of any one of the first aspect or the display module of any one of the second aspect.

[0016] As can be seen from the above, the display module, the preparation method thereof and the display device provided by the present application control the first pre-shrinking ratio to be greater than the second pre-shrinking ratio, so that the pre-shrinking amount in the second pre-shrinking direction is smaller than the pre-shrinking amount in the first pre-shrinking direction. In this way, the smaller pre-shrinking amount in the second pre-shrinking direction can exactly offset the smaller expansion amount in the second heat expansion direction, and the larger pre-shrinking amount in the first pre-shrinking direction can exactly offset the larger expansion amount in the first heat expansion direction, thereby making each pin on the circuit board accurately aligned and connected with the corresponding conductive part after hot pressing and binding, and improving the binding alignment accuracy of the circuit board. BRIEF DESCRIPTION OF DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the present application or related art, the following will briefly introduce the drawings needed to be used in the embodiments or related art description. Obviously, the drawings in the following description are only embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0018] Figure 1a The structure diagram of the circuit board with the binding part being continuous and without disconnection in the related art;

[0019] Figure 1bA structure diagram of a circuit board with adjacent binding parts disconnected in the related art;

[0020] Figure 1c A structure diagram of a flexible circuit board and a substrate after binding connection in the related art;

[0021] Figures 2a-2c A structure diagram of a related "U" type large FPC design pre-shrinking method one;

[0022] Figures 3a-3c A structure diagram of a related "U" type large FPC design pre-shrinking method two;

[0023] Figure 4 A first structure diagram of a display module of an embodiment of the present application;

[0024] Figure 5 A second structure diagram of a display module of an embodiment of the present application;

[0025] Figure 6 A partial enlarged diagram of a structure diagram in the description; Figure 5

[0026] Figure 7 A first heating principle diagram of a circuit board of an embodiment of the present application;

[0027] Figure 8 A third structure diagram of a display module of an embodiment of the present application;

[0028] Figure 9 A fourth structure diagram of a display module of an embodiment of the present application;

[0029] Figure 10 A partial enlarged diagram of a structure diagram in the description; Figure 9

[0030] Figure 11 A first structure diagram of a circuit board of an embodiment of the present application;

[0031] Figure 12 A fifth structure diagram of a display module of an embodiment of the present application;

[0032] Figure 13 A structure diagram of a display panel of an embodiment of the present application;

[0033] Figure 14 A sixth structure diagram of a display module of an embodiment of the present application;

[0034] Figure 15 A seventh structure diagram of a display module of an embodiment of the present application;

[0035] Figure 16 ​​A partial enlarged schematic view of the drawing; Figure 15

[0036] Figure 17 A structure schematic view of a display module of an embodiment of the present application when performing a hot-pressing process;

[0037] Figure 18 An eighth structure schematic view of a display module of an embodiment of the present application;

[0038] Figure 19 A second heat-receiving principle schematic view of a circuit board of an embodiment of the present application;

[0039] Figure 20 A principle schematic view of a circuit board of an embodiment of the present application before and after binding;

[0040] Figure 21 A second structure schematic view of a circuit board of an embodiment of the present application;

[0041] Figure 22 A third structure schematic view of a circuit board of an embodiment of the present application;

[0042] Figure 23 A ninth structure schematic view of a display module of an embodiment of the present application;

[0043] Figure 24 A structure schematic view of a display module of an embodiment of the present application after alignment of a first pin and a first conductive part;

[0044] Figure 25 A fourth structure schematic view of a circuit board of an embodiment of the present application.

[0045] In the drawing: 01, flexible circuit board; 011, gold finger; 02, substrate; 03, conductive contact; 04, IC; 1, display panel; 11, binding area; 111, conductive part; 1111, first conductive part; 112, alignment conductive part; 113, first alignment structure; 2, circuit board; 21, binding part; 211, pin; 2111, first pin; 212, alignment pin; 213, second alignment structure; 22, reinforcing plate; 3, conductive adhesive layer; 4, first side wall; 5, second side wall; 6, hot-pressing head. DETAILED DESCRIPTION

[0046] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application is further described in detail below with reference to specific embodiments and the accompanying drawings.

[0047] ​It should be noted that, unless otherwise defined, technical terms or scientific terms used in the embodiments of the present application shall have the common meaning understood by one of ordinary skill in the art to which the embodiments of the present application belong. The terms "first", "second" and similar terms used in the embodiments of the present application do not denote any order, quantity or importance, but are only used to distinguish different components. The terms "include" or "contain" and similar terms mean that the elements or objects before the terms encompass the elements or objects listed after the terms and their equivalents, and do not exclude other elements or objects. The terms "connect" or "connected" and similar terms are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. The terms "upper", "lower", "left", "right" and the like only represent relative positional relationships, which can change accordingly when the absolute positions of the described objects change.

[0048] The existing large-size flexible printed circuit (FPC) mainly has two structures: one is that the binding part is continuous as a whole without disconnection (as shown in Figure 1a ), and the other is that the binding parts are disconnected between adjacent binding parts, and two binding parts form a "U" shape (as shown in Figure 1b ).

[0049] In a display product, as shown in Figure 1c , the flexible printed circuit 01 needs to be connected with the substrate 02, specifically, the gold fingers 011 of the binding area of the flexible printed circuit need to be aligned with the conductive pads 03 of the binding area of the substrate 02, and then the binding connection is made through a hot pressing process.

[0050] When designing a conventional large FPC for a vehicle, the production binding process requirements need to be met. When the FPC is bound to the glass, the temperature is relatively high, and the thermal expansion is obvious, so the gold fingers 011 (also referred to as "pins") of the binding area need to be pre-shrunk. Whether the binding is qualified is judged according to the binding alignment offset a (i.e., the alignment offset of the FPC gold fingers 011 and the conductive pads 03 of the glass), which is not more than 1 / 2 of the width b of the FPC gold fingers 011. If it is less than 1 / 2 of b, it is determined that the binding is qualified.

[0051] The pre-shrinking design method of the existing vehicle large FPC with disconnected adjacent binding parts ("U" shape) is basically divided into two types:

[0052] I. Related "U" shape large FPC design pre-shrinking method

[0053] The total distance of the gold fingers 011 of the single binding part from the first Pin (Pin means pin) to the Nth Pin is pre-shrunk, and the center distance dimension of the two mark patterns (i.e., Mark) of the single binding part is controlled with a tolerance, as shown in Figure 2a , Figure 2band Figure 2c as shown.

[0054] In the figure, M1 is the dimension of the center distance of two Marks of the left binding part A; M2 is the dimension of the center distance of two Marks of the right binding part B; T pitch1 , T pitch2 is the total pitch (i.e. total distance) of the gold fingers 011 from the first Pin to the Nth Pin of a single binding part.

[0055] The dimensions M1 and M2 are the same as the center distance of the Marks on the substrate 02, and the conventional design tolerance is ±0.03 mm.

[0056] T pitch1 , T pitch2 The dimensions after the pre-shrinking design need to be pre-shrunk according to the pre-shrinking ratio, which is given by the process according to the project difference.

[0057] The pre-shrinking ratio refers to the ratio of the difference between the dimension before pre-shrinking and the dimension after pre-shrinking of a single binding area of the flexible circuit board to the dimension before pre-shrinking. The dimension before pre-shrinking is designed according to the corresponding dimension of the binding area on the glass substrate 02, and then the dimension after pre-shrinking is calculated based on the dimension before pre-shrinking and the pre-shrinking ratio.

[0058] That is, T pitch1 = T pitch2 = P 1～N (i.e. the center distance of the Pins 1 to N on the glass) - P 1～N * pre-shrinking ratio.

[0059] This pre-shrinking design is based on the fact that when the FPC is bound to the glass, the two binding parts (binding area A and binding area B) are expanded by heat, while the corresponding reinforcing area M between the binding parts A and B, as well as the reinforcing area L corresponding to the binding part A and the reinforcing area R corresponding to the binding part A, do not expand.

[0060] In fact, the reinforcing area M, the reinforcing area L and the reinforcing area R have thermal expansion, so that the first Pin f and the tail Pin e of the FPC move outward to the left and right sides respectively, and the first Pin and the tail Pin move outward beyond the outer side of the corresponding conductive contact 03 of the glass. At the same time, the outermost Marks of the FPC on the left and right sides move outward beyond the conductive contact 03 of the glass in the same direction, as shown in Figure 4 .

[0061] The actual outward expansion of the FPC by this pre-shrinking method has been experimentally verified, and the proportion of the bad rate when the offset (af, ae) is greater than or equal to 1 / 2 of the width of the FPC gold finger 011 is more than 30%.

[0062] Wherein, af is the binding alignment offset of the FPC and the glass first Pin, and ae is the binding alignment offset of the FPC and the glass tail Pin.

[0063] II. Related "U" type large FPC design pre-shrinking method two

[0064] The FPC of this pre-shrinking method contains two pre-shrinking directions: the first pre-shrinking direction and the second pre-shrinking direction, as shown in Figure 3a 、 Figure 3b and Figure 3c .

[0065] The FPC pre-shrinking method contains two pre-shrinking directions pre-shrinking at the same time, the first pre-shrinking direction is used for the single binding part, and the pre-shrinking ratio is the same as the first pre-shrinking method. The total pitch (Ptotal) of the first Pin f of the binding part A to the tail Pin e of the binding part B uses the second pre-shrinking direction, and the pre-shrinking ratio is the same as the first pre-shrinking direction. The center distance dimension of the two Marks of the single binding part plus the tolerance is controlled, and the center distance dimension of the inner side Mark B to Mark C plus the tolerance is controlled.

[0066] In the figure, M1 is the center distance dimension of the two Marks of the left binding part A, M2 is the center distance dimension of the two Marks of the right binding part B, M is the center distance dimension of the inner side Mark B to Mark C, T pitch1 、T pitch2 is the total pitch of the first Pin to the Nth Pin of the gold finger 011 of the single binding part, P total is the total distance of the first Pin (the leftmost gold finger 011) to the tail Pin (the rightmost gold finger 011).

[0067] M1, M2, M, and the center distance dimension of the Marks on the glass substrate 02 are the same, and the conventional design tolerance is ±0.03mm.

[0068] T pitch1 =T pitch2 =P 1～N (central distance of Pin 1 to Pin N on the glass)-P 1～N *(0.0008-0.001).

[0069] P total =P pad (central distance of the first Pin conductive patch 03 to the tail Pin conductive patch 03 on the glass)-P pad *(0.0008-0.001).

[0070] This pre-shrinking design is based on: in addition to the two binding parts (binding part A and binding part B) of the FPC having thermal expansion, the corresponding first and tail Pins of the entire reinforcing plate of the FPC are also pre-shrunk (corresponding to the second pre-shrinking direction).

[0071] In this pre-shrinking method, the pre-shrinking ratio of the second pre-shrinking direction is the same as the pre-shrinking ratio of the first pre-shrinking direction.

[0072] The inventor found through practice that, if the FPC single section and the whole are pre-shrunk twice in the same proportion, the gold finger 011 will deviate greatly from the glass conductive contact 03 after the FPC is bound to the glass, and will be seriously deviated to the inner side or the outer side of the conductive contact 03, so that the total number of effective conductive adhesive layer balls at the binding position of the gold finger 011 is not enough, the electrical conductivity is poor, the potential risk of contact reliability is high, the production yield is affected, the production cost is high, and the product benefit is low. Experiments show that, if the FPC single section and the whole are pre-shrunk twice in the same proportion, the FPC will be shrunk after actual alignment, and the deviation amount is greater than one-half of the width of the FPC gold finger 011, and the proportion of the bad rate is about 50%, and the deviation amount increases significantly.

[0073] After a large number of experimental verifications, the inventor found that the reason for the significant increase in the deviation amount is that the pre-shrinking value in the second pre-shrinking direction is much larger than the actual required amount. This is because, when the FPC is bound through the hot-pressing process, the temperature rise of the reinforcing plate and the binding part is different, and the temperature is much lower than that of the binding part A and the binding part B. Therefore, if the FPC single section and the whole use the same pre-shrinking proportion, the FPC pre-shrinking amount will be too large, so that after the FPC is bound to the glass, the first Pin f and the tail Pin e of the FPC are deviated to the inner side direction of the corresponding glass conductive contact 03 (i.e. the FPC is shrunk).

[0074] Based on this, referring to FIGS. Figure 4 , Figure 5 and Figure 6 , the display module provided by the present application is provided, wherein the circuit board 2 and the display panel 1 are only preliminarily connected, and have not been bound and connected through the hot-pressing process, and the various dimensions of the circuit board 2 are the dimensions before binding, i.e. the dimensions after pre-shrinking according to the design.

[0075] The display module comprises:

[0076] a display panel 1, wherein the display panel 1 is provided with at least two binding areas 11, and each binding area 11 comprises a plurality of conductive parts 111 arranged at intervals;

[0077] a circuit board 2, comprising at least two binding parts 21 arranged at intervals, and each binding part 21 comprises a plurality of pins 211 arranged at intervals, and the plurality of pins 211 of each binding part 21 correspond to and are connected to the plurality of conductive parts 111 of one binding area 11;

[0078] The distance between the first center axis of the first pin 2111 of each of the binding portions 21 and the second center axis of the binding portion 21 is a first distance, the distance between the third center axis of the first conductive portion 1111 of the binding area 11 corresponding to the binding portion 21 and the fourth center axis of the binding area 11 is a second distance, the first pin 2111 is a pin 211 away from the second center axis among the plurality of pins 211, the first conductive portion 1111 is a conductive portion 111 corresponding to the first pin 2111, and the ratio of the difference between the second distance and the first distance to the second distance is a first pre-shrinking ratio;

[0079] The distance between the second center axes of two adjacent binding portions 21 is a third distance, and the distance between the fourth center axes of two adjacent binding areas 11 is a fourth distance, and the ratio of the difference between the fourth distance and the third distance to the fourth distance is a second pre-shrinking ratio.

[0080] The first pre-shrinking ratio is greater than the second pre-shrinking ratio.

[0081] Specifically, the display panel 1 is provided with at least two binding areas 11, and each of the binding areas 11 includes a plurality of conductive portions 111 arranged at intervals, which are made of conductive material and used for binding connection with the circuit board 2.

[0082] The circuit board 2 includes at least two binding portions 21 arranged at intervals, and the number of the binding portions 21 is the same as the number of the binding areas 11, so that the at least two binding portions 21 correspond to the at least two binding areas 11 one by one. Exemplarily, the circuit board 2 can be a flexible circuit board 2.

[0083] The circuit board 2 is also provided with a reinforcing plate 22, which is used as a base material to ensure the strength of the entire circuit board 2. The binding area 11 is arranged on one side of the reinforcing plate 22, and the reinforcing plate 22 can support the binding area 11.

[0084] Each of the binding portions 21 includes a plurality of pins 211 arranged at intervals, and the plurality of pins 211 of each of the binding portions 21 correspond to and are connected to the plurality of conductive portions 111 of one of the binding areas 11. At this time, the connection is an initial connection and has not been bound by a hot pressing process, so the size of the circuit board 2 at this time is a size after pre-shrinking according to a pre-shrinking ratio set in advance before binding. The pre-shrunk circuit board 2 is connected to the display panel 1, and then hot pressing is performed by a hot pressing process. During the hot pressing process, the circuit board 2 expands due to heat, thereby increasing the size of the circuit board 2.

[0085] Therefore, when the circuit board 2 is connected to the display panel 1, the size before binding is closely related to the size after binding. If you want to control the size after binding to meet the process requirements, then you must strictly control the size before binding to ensure that the offset between the circuit board 2 and the display panel 1 after binding meets the process requirements.

[0086] For specific implementation, see Figure 7 As shown, during the hot pressing process, the heated area of ​​the circuit board 2 is divided into two parts. The first heated area is the area where the binding portion 21 is located. The heating of this area will cause the binding portion 21 to move along the Figure 7 The second heated area is the area where the lower base of the binding portion 21 is located. When heated, the base material will expand to both sides. The expansion of the base material will drive the binding portion 21 on the base material to expand along the Figure 7 The second thermal expansion direction shown is expansion.

[0087] Therefore, when designing pre-shrinkage, it is necessary to consider the expansion in these two directions. Figure 8 As shown, when performing the preset design, each binding portion 21 needs to be along Figure 8 The first pre-shrinking direction shown is pre-shrinked to correspond to the expansion of the binding portion 21 in the first heat expansion direction during the hot pressing process. In addition, the two adjacent binding portions 21 need to be pre-shrinked along the first pre-shrinking direction. Figure 8 The second pre-shrinkage direction shown is pre-shrinkage to correspond to the expansion of the binding portion 21 in the first heat expansion direction during the hot pressing process.

[0088] Although the first pre-shrinkage direction and the second pre-shrinkage direction are determined, as mentioned above, if the pre-shrinkage ratio in the first pre-shrinkage direction and the second pre-shrinkage direction is not appropriate, it will cause the pre-shrinkage amount to be too large or too small, and ultimately cause the offset between the circuit board 2 and the display panel 1 after binding to be too large, which does not meet the process requirements.

[0089] Based on this, in the present application, the first pre-shrinkage ratio is controlled to be greater than the second pre-shrinkage ratio, wherein the first pre-shrinkage ratio is the pre-shrinkage ratio in the first pre-shrinkage direction, and the second pre-shrinkage ratio is the pre-shrinkage ratio in the second pre-shrinkage direction.

[0090] Specifically, see Figure 9 、 Figure 10 and Figure 11 As shown, the ratio of the difference between the second distance and the first distance to the second distance is the first pre-shrinkage ratio, wherein the first central axis of the first pin 2111 of each binding portion 21 (ie Figure 11 ) and the second central axis of the binding portion 21 (ie Figure 11 The distance between them is the first distance (i.e. Figure 11, as shown by T1 in FIG. ). The first pin 2111 is the pin 211 away from the second central axis among the plurality of pins 211. The pins 211 described in this embodiment are effective pins 211 in the binding portion 21, i.e., pins 211 that function as effective electrical connections, and do not include pins 211 used for alignment or pins 211 used to assist in maintaining uniformity of the binding portion 21.

[0091] The third central axis (ie the first conductive portion 1111 of the binding area 11 corresponding to the binding portion 21) Figure 9 and Figure 10 3 in FIG) and the fourth central axis of the binding region 11 (ie Figure 9 and Figure 10 The distance between them is the second distance (i.e. Figure 9 and Figure 10 The first conductive portion 1111 is a conductive portion 111 corresponding to the first pin 2111.

[0092] That is, the first distance is the distance between the first center axis of the first pin 2111 of each binding part 21 after pre-shrinkage and the second center axis of the binding part 21, and the second distance is the theoretical distance between the first center axis of the first pin 2111 of each binding part 21 and the second center axis of the binding part 21 before pre-shrinkage (that is, the relevant distance of the corresponding binding area 11).

[0093] The ratio of the difference between the fourth distance and the third distance to the fourth distance is the second pre-shrinkage ratio, wherein the second central axis of two adjacent binding parts 21 (ie Figure 11 The distance between them is the third distance (i.e. Figure 11 The fourth central axis of the two adjacent binding regions 11 (ie Figure 9 and Figure 10 The distance between them is the fourth distance (i.e. Figure 9 and Figure 10 (as shown in D in the figure).

[0094] That is, the third distance is the distance between the second center axes of two adjacent binding parts 21 after pre-shrinkage, and the fourth distance is the theoretical distance between the second center axes of two adjacent binding parts 21 before pre-shrinkage (that is, the relevant distance of the corresponding binding area 11).

[0095] Since the temperature of the reinforcing plate 22 is much lower than that of the binding part 21 due to the different temperature rises of the reinforcing plate 22 (or the base material) and the binding part 21 during the binding of the FPC through the hot-pressing process, the expansion amount in the second heat expansion direction is much smaller than that in the first heat expansion direction. Therefore, in the present application, the first pre-shrinkage ratio is controlled to be greater than the second pre-shrinkage ratio, so that the pre-shrinkage amount in the second pre-shrinkage direction is smaller than that in the first pre-shrinkage direction during the pre-shrinkage design. In this way, the smaller pre-shrinkage amount in the second pre-shrinkage direction can offset the smaller expansion amount in the second heat expansion direction, and the larger pre-shrinkage amount in the first pre-shrinkage direction can offset the larger expansion amount in the first heat expansion direction. Thus, after the hot-pressing binding, each pin 211 on the circuit board 2 can be accurately aligned and bound with the corresponding conductive part 111, thereby improving the binding alignment accuracy of the circuit board 2.

[0096] In addition, in the present application, the pin 211 is an effective pin 211 in the binding part 21, that is, a pin 211 that plays an effective electrical connection role, and does not include a pin 211 for alignment or a pin 211 for assisting in maintaining the uniformity of the binding part 21. When determining the pre-shrinkage amount and the pre-shrinkage ratio, the distances are determined based on the center axis of the first pin 2111, which is a pin 211 farthest from the second center axis among the plurality of pins 211 in a certain binding part 21, that is, the first effective pin 211 or the last effective pin 211 in the binding part 21.

[0097] That is, when determining the distances, the first effective pin 211 and the last effective pin 211 are used as the reference, rather than the alignment pin 212. In this way, the accuracy of the pre-shrinkage design can be improved, thereby improving the alignment accuracy.

[0098] This is because, in actual testing, the alignment offset of the effective pin 211 is tested, rather than the alignment offset of the alignment pin 212. That is, the alignment offset of the alignment pin 212 cannot represent whether the alignment binding is qualified or not. Therefore, in the present application, the first effective pin 211 and the last effective pin 211 are used as the reference, rather than the alignment pin 212. In this way, the accuracy of the pre-shrinkage design can be improved, thereby improving the alignment accuracy.

[0099] In some embodiments, the first pre-shrinkage ratio is 0.0008-0.001, and the second pre-shrinkage ratio is 0.0001-0.0003.

[0100] Specifically, the first pre-shrinkage ratio can be 0.0008, 0.0009, 0.001, etc. The second pre-shrinkage ratio can be 0.0001, 0.0002, 0.0003, etc.

[0101] When the first and second pre-shrinking ratios are within the range, the pre-shrinking amount in the first pre-shrinking direction and the pre-shrinking amount in the second pre-shrinking direction are moderate, which can just offset the expansion amount in the second heat expansion direction and the second heat expansion direction, so that after heat pressing and binding, each pin 211 on the circuit board 2 can be accurately aligned and bound with the corresponding conductive part 111, thereby improving the binding alignment accuracy of the circuit board 2.

[0102] In some embodiments, the distance P' between the first center axes of the first pins 2111 of the two adjacent binding parts 21 is calculated according to the following formula:

[0103] P' = P - (T 21 ×m1) - (D×m2) - (T 22 ×m1);

[0104] wherein P is the distance between the third center axes of the first conductive parts 1111 of the two adjacent binding areas 11, T 21 is the second distance of one of the two adjacent binding areas 11, T 22 is the second distance of the other of the two adjacent binding areas 11, m1 is the first pre-shrinking ratio, D is the fourth distance, and m2 is the second pre-shrinking ratio.

[0105] Specifically, P is the distance between the third center axes (i.e., O3 in the above formula) of the first conductive parts 1111 of the two adjacent binding areas 11, i.e., the theoretical distance between the first center axes of the first pins 2111 of the two adjacent binding parts 21 before pre-shrinking. Figure 12

[0106] T 21 is the second distance of one of the two adjacent binding areas 11, i.e., the theoretical first distance of the binding part 21 corresponding to the binding area 11 before pre-shrinking. m1 is the first pre-shrinking ratio, and T 21 ×m1 is the pre-shrinking amount of one of the two adjacent binding parts 21 in the first pre-shrinking direction.

[0107] Correspondingly, T 22 ×m1 is the pre-shrinking amount of the other of the two adjacent binding parts 21 in the first pre-shrinking direction.

[0108] D is the fourth distance, i.e., the theoretical third distance before pre-shrinking, m2 is the second pre-shrinking ratio, and D×m2 is the overall pre-shrinking amount of the two binding parts 21 in the second pre-shrinking direction.

[0109] Therefore, P - (T 21 ×m1) - (D×m2) - (T 22 ​The distance represented by xm1 is the distance between the two binding portions 21 before pre-shrinking minus the pre-shrinking amount in the first pre-shrinking direction and the pre-shrinking amount in the second pre-shrinking direction, and the final result is the distance between the two binding portions 21 after pre-shrinking.

[0110] In the present application, the distance P' between the first center axes of the first pins 2111 of the two adjacent binding portions 21 is determined based on the specific first pre-shrinking ratio and the second pre-shrinking ratio, and the second distance and the fourth distance, which can effectively improve the accuracy of the finally determined P' and in turn improve the alignment accuracy.

[0111] In some embodiments, continuing to refer to Figure 9 As shown, each of the binding portions 21 further includes at least two alignment pins 212, and the at least two alignment pins 212 are respectively located on the two sides of the plurality of pins 211. Each of the binding areas 11 further includes at least two alignment conductive portions 112, and the at least two alignment conductive portions 112 are respectively located on the two sides of the plurality of conductive portions 111. Each of the alignment conductive portions 112 corresponds to an alignment pin 212.

[0112] Specifically, the alignment pins 212 are used as alignment marks, which do not connect circuits and are only used to assist alignment. The alignment conductive blocks are correspondingly arranged with the alignment pins 212. The alignment of the alignment conductive blocks and the alignment pins 212 is used to assist the accurate alignment of the pins 211 and the corresponding conductive portions 111.

[0113] Each of the binding portions 21 includes at least two alignment pins 212, and the at least two alignment pins 212 are respectively located on the two sides of the plurality of pins 211. Each of the binding areas 11 further includes at least two alignment conductive portions 112, and the at least two alignment conductive portions 112 are respectively located on the two sides of the plurality of conductive portions 111. In this way, the area where the plurality of pins 211 and the plurality of conductive portions 111 are located is referred to as an alignment area. The alignment of each of the alignment pins 212 and the corresponding alignment conductive block can assist the alignment of one side of the alignment area. The alignment of the two alignment pins 212 and the corresponding alignment conductive block at the same time can assist the alignment of both sides of the alignment area at the same time, thereby improving the alignment accuracy.

[0114] In some embodiments, continuing to refer to Figure 10 and Figure 11As shown, each of the binding areas 11 further comprises at least two first alignment structures 113, and the at least two first alignment structures 113 are respectively located on one side of each of the alignment conductive parts 112 away from the fourth central axis; each of the binding parts 21 further comprises at least two second alignment structures 213, and the at least two second alignment structures 213 are respectively located on one side of each of the alignment pins 212 away from the second central axis, and each of the second alignment structures 213 corresponds to a first alignment structure 113.

[0115] Specifically, the at least two first alignment structures 113 are respectively located on one side of each of the alignment conductive parts 112 away from the fourth central axis, i.e., the first alignment structure 113 is located on the outer side of the alignment conductive part 112. The at least two second alignment structures 213 are respectively located on one side of each of the alignment pins 212 away from the second central axis, i.e., the second alignment structure 213 is located on the outer side of the alignment pin 212. In this way, the distance between two adjacent first alignment structures 113 is greater than the distance between two adjacent alignment conductive parts 112, and the distance between two adjacent second alignment structures 213 is greater than the distance between two adjacent alignment pins 212.

[0116] For the alignment process, the alignment equipment has higher grabbing accuracy when automatically grabbing two alignment marks far away from each other, and thus the alignment accuracy of the two alignment marks can be controlled. Therefore, in the present application, the alignment equipment has better accuracy when grabbing two adjacent first alignment structures 113 in the actual alignment process, so that the second alignment structure 213 and the first alignment structure 113 can be accurately aligned, and thus the alignment accuracy between the plurality of pins 211 and the corresponding conductive parts 111 can be improved.

[0117] When the grabbing equipment cannot accurately grab the first alignment structure 113 due to special reasons (for example, the distance between two first alignment structures 113 is too far, or the first alignment structure 113 is damaged, etc.), the second alignment structure 213 and the first alignment structure 113 cannot be accurately aligned, and at this time, the grabbing equipment needs to grab two adjacent alignment conductive parts 112 close to each other to control the accurate alignment between the alignment pin 212 and the corresponding alignment conductive part 112, so that the alignment pin 212 and the corresponding alignment conductive part 112 can still be accurately aligned when the first alignment structure 113 and the second alignment structure 213 cannot be accurately aligned, and the alignment accuracy between the circuit board 2 and the display panel 1 is improved.

[0118] The present application also provides a preparation method of a display module, comprising:

[0119] Step S100, providing a display panel 1, wherein the display panel 1 is provided with at least two binding areas 11, each of the binding areas 11 comprises a plurality of conductive parts 111 arranged at intervals, wherein the distance between the third center axis of the first conductive part 1111 of the binding area 11 and the fourth center axis of the binding area 11 is a second distance, and the distance between the fourth center axes of two adjacent binding areas 11 is a fourth distance;

[0120] Step S200, determining a first pre-shrinking ratio and a second pre-shrinking ratio of the circuit board 2, wherein the first pre-shrinking ratio is greater than the second pre-shrinking ratio, and the circuit board 2 comprises at least two binding parts 21 arranged at intervals, each of the binding parts 21 comprises a plurality of pins 211 arranged at intervals;

[0121] Step S300, determining the size of the circuit board 2 after pre-shrinking based on the first pre-shrinking ratio, the second pre-shrinking ratio, the second distance and the fourth distance, to obtain a pre-shrunk circuit board 2;

[0122] Step S400, aligning each of the binding parts 21 of the pre-shrunk circuit board 2 with one of the binding areas 11 of the display panel 1, and binding and connecting by a hot pressing process, so that the plurality of pins 211 of each of the binding parts 21 correspond to and bind with the plurality of conductive parts 111 of one of the binding areas 11.

[0123] Specifically, when preparing a display module, a display panel 1 and a circuit board 2 need to be provided first.

[0124] Referring to Figure 13 As shown in the figure, the display panel 1 is provided with at least two binding areas 11, each of the binding areas 11 comprises a plurality of conductive parts 111 arranged at intervals, wherein the distance between the third center axis of the first conductive part 1111 of the binding area 11 and the fourth center axis of the binding area 11 is a second distance, and the distance between the fourth center axes of two adjacent binding areas 11 is a fourth distance.

[0125] As Figure 11 As shown in the figure, the circuit board 2 comprises at least two binding parts 21 arranged at intervals, each of the binding parts 21 comprises a plurality of pins 211 arranged at intervals.

[0126] After providing the display panel 1 and the circuit board 2, the circuit board 2 needs to be pre-shrunk to obtain the specific size of the pre-shrunk circuit board 2.

[0127] Specifically, first, according to the actual project requirements, the specific values of the first pre-shrinking ratio and the second pre-shrinking ratio of the circuit board 2 are determined. In this embodiment, the first pre-shrinking ratio is 0.0008-0.001, and the second pre-shrinking ratio is 0.0001-0.0003.

[0128] Secondly, based on the first pre-shrinkage ratio, the second pre-shrinkage ratio, the second distance and the fourth distance, the pre-shrunk size of the circuit board 2 is determined.

[0129] Finally, after the pre-shrunk size of the circuit board 2 is determined, the alignment and binding connection between the circuit board 2 and the display panel 1 need to be performed. Specifically, each of the binding parts 21 of the pre-shrunk circuit board 2 is aligned with one of the binding areas 11 of the display panel 1, and the binding connection is performed through a hot pressing process, so that the plurality of pins 211 of each of the binding parts 21 correspond to and are connected with the plurality of conductive parts 111 of one of the binding areas 11 one by one.

[0130] In the present application, before the circuit board 2 is pre-shrunk, the first pre-shrinkage ratio and the second pre-shrinkage ratio are determined according to actual needs, then based on the first pre-shrinkage ratio, the second pre-shrinkage ratio, the second distance and the fourth distance, the pre-shrunk size of the circuit board 2 is determined, and finally the pre-shrunk circuit board 2 is connected with the display panel 1. Since the first pre-shrinkage ratio is controlled to be greater than the second pre-shrinkage ratio, the pre-shrinkage amount in the second pre-shrinkage direction is smaller than that in the first pre-shrinkage direction when pre-shrinking is designed. In this way, the smaller pre-shrinkage amount in the second pre-shrinkage direction can offset the smaller expansion amount in the second heat expansion direction, and the larger pre-shrinkage amount in the first pre-shrinkage direction can offset the larger expansion amount in the first heat expansion direction, so that after hot pressing and binding, each pin 211 on the circuit board 2 can be accurately aligned and connected with the corresponding conductive part 111, thereby improving the binding alignment accuracy of the circuit board 2.

[0131] In some embodiments, the determination of the pre-shrunk size of the circuit board 2 based on the first pre-shrinkage ratio, the second pre-shrinkage ratio, the second distance and the fourth distance comprises:

[0132] Based on the first pre-shrinkage ratio, the second pre-shrinkage ratio, the second distance and the fourth distance, the first distance between the first center axis of the first pin 2111 of each of the binding parts 21 of the circuit board 2 and the second center axis of the binding part 21, and the distance between the first center axes of the first pins 2111 of the adjacent two binding parts 21 are determined, to determine the pre-shrunk size of the circuit board 2.

[0133] Specifically, referring to Figure 11 to determine the pre-shrunk size of the circuit board 2, the specific sizes of the following three parts need to be determined to finally determine the accurate pre-shrunk size of the circuit board 2. Specifically, it includes:

[0134] First part: the size of the distance between the first pin 2111 and the edge of the circuit board 2. This part of the size is a standard in the industry, which can be set according to the standard;

[0135] The second part: a first distance between the first central axis of the first pin 2111 of each binding portion 21 and the second central axis of the binding portion 21 (i.e. Figure 11 The first distance can be calculated based on the first pre-shrinkage ratio and the second distance. Specifically, the product of the second distance and the first pre-shrinkage ratio is determined as the pre-shrinkage distance, and the difference between the second distance and the pre-shrinkage distance is determined as the first distance. In this way, the first distance after pre-shrinkage can be determined.

[0136] The third part: the second distance between the second central axes of two adjacent binding parts 21 (i.e. Figure 11 The calculation of the second distance essentially requires determining the distance between two adjacent binding portions 21. Therefore, based on the determination of the first distance, if the distance between the first central axes of the first pins 2111 of the two adjacent binding portions 21 can be determined (i.e. Figure 11 ), then it is equivalent to determining the second distance.

[0137] Therefore, in the present application, based on the first pre-shrinkage ratio, the second pre-shrinkage ratio, the second distance and the fourth distance, the distance between the first central axes of the first pins 2111 of the two adjacent binding parts 21 of the circuit board 2 is determined. Specifically, the distance Pˊ between the first central axes of the first pins 2111 of the two adjacent binding parts 21 is calculated according to the following formula: Pˊ=P–(T 21 ×m1)–(D×m2)–(T 22 ×m1);

[0138] Wherein, P is the distance between the third central axes of the first conductive portions 1111 of two adjacent binding regions 11, T 21 is the second distance between one of the two adjacent binding areas 11, T 22 is the second distance of the other binding area 11 of the two adjacent binding areas 11, m1 is the first pre-shrinkage ratio, D is the fourth distance, and m2 is the second pre-shrinkage ratio.

[0139] Specifically, P is the third central axis of the first conductive portion 1111 of two adjacent binding regions 11 (ie Figure 12 3), that is, the theoretical distance between the first central axes of the first pins 2111 of two adjacent binding portions 21 before pre-shrinkage.

[0140] T 21 is the second distance of one of the two adjacent binding areas 11, that is, the theoretical first distance of the binding portion 21 corresponding to the binding area 11 before pre-shrinkage. m1 is the first pre-shrinkage ratio, T 21 ×m1 is the pre-shrinkage amount of one of the two adjacent binding portions 21 in the first pre-shrinkage direction.

[0141] Correspondingly, T 22 Xm1 is the shrinkage of the other one of the two adjacent binding portions 21 in the first shrinkage direction.

[0142] D is the fourth distance, i.e. the theoretical third distance before shrinkage, m2 is the second shrinkage ratio, and Dxm2 is the overall shrinkage of the two binding portions 21 in the second shrinkage direction.

[0143] Therefore, P-(T 21 Xm1)-(Dxm2)-(T 22 Xm1) is the distance between the two binding portions 21 before shrinkage minus the shrinkage in the first shrinkage direction and the shrinkage in the second shrinkage direction, and the final result is the distance between the two binding portions 21 after shrinkage.

[0144] In this application, based on the first shrinkage ratio, the second shrinkage ratio, the second distance and the fourth distance, the first distance between the first center axis of the first pin 2111 of each binding portion 21 of the circuit board 2 and the second center axis of the binding portion 21, and the distance between the first center axes of the first pins 2111 of the two adjacent binding portions 21 can be accurately determined. In this way, the dimensions of each part of the circuit board 2 can be accurately controlled, so that when the circuit board 2 is bonded and connected to the display panel 1 through the hot pressing process, the heat expansion amount and the shrinkage amount of each part of the circuit board 2 are basically consistent, and the alignment accuracy of the circuit board 2 and the display panel 1 is improved.

[0145] In some embodiments, the aligning each binding portion 21 of the circuit board 2 after shrinkage with a binding area 11 of the display panel 1, and bonding and connecting through the hot pressing process, so that the plurality of pins 211 of each binding portion 21 correspond one by one and are bonded and connected to the plurality of conductive portions 111 of a binding area 11, comprises:

[0146] Aligning each binding portion 21 with a binding area 11, so that the fifth center axis between the two adjacent binding portions 21 at least partially coincides with the sixth center axis of the corresponding two adjacent binding areas 11;

[0147] Bonding and connecting each binding portion 21 with a binding area 11 through the hot pressing process.

[0148] Specifically, the aligning each of the binding portions 21 with one of the binding areas 11 comprises: aligning each of the second alignment structures 213 with one of the first alignment structures 113, and aligning each of the alignment pins 212 of the binding portions 21 with the alignment conductive portions 112 of the corresponding binding areas 11, so as to align each of the binding portions 21 with one of the binding areas 11. In this way, through the alignment between the first alignment structures 113 and the second alignment structures 213, and the alignment between the alignment pins 212 and the alignment conductive portions 112, the alignment accuracy between each of the pins 211 and the corresponding alignment conductive portions 112 can be improved, and thus the alignment accuracy between the circuit board 2 and the display panel 1 can be improved.

[0149] In some embodiments, the binding connection between each of the binding portions 21 and one of the binding areas 11 is performed through a hot-pressing process.

[0150] A conductive adhesive layer 3 is arranged between the binding portions 21 and the binding areas 11.

[0151] After the binding portions 21 and the binding areas 11 are heated to a preset temperature, the binding portions 21 and the binding areas 11 are pressed at a preset pressure, so that the plurality of pins 211 of each of the binding portions 21 are in one-to-one correspondence with and are bound to the plurality of conductive portions 111 of one of the binding areas 11.

[0152] Specifically, referring to Figure 14 a conductive adhesive layer 3 is arranged between the binding portions 21 and the binding areas 11, and after the binding portions 21 and the binding areas 11 are heated to a preset temperature, the binding portions 21 and the binding areas 11 are pressed at a preset pressure, so that the plurality of pins 211 of each of the binding portions 21 are in one-to-one correspondence with and are bound to the plurality of conductive portions 111 of one of the binding areas 11.

[0153] The preset temperature and the preset pressure are both conventional parameters in the hot-pressing process of the circuit board 2 and the display panel 1, and are not specifically limited herein, and can be selected according to actual process parameters.

[0154] In some embodiments, after the aligning each of the binding portions 21 of the pre-shrunk circuit board 2 with one of the binding areas 11 of the display panel 1, and the binding connection between each of the binding portions 21 and one of the binding areas 11 is performed through a hot-pressing process, so that the plurality of pins 211 of each of the binding portions 21 are in one-to-one correspondence with and are bound to the plurality of conductive portions 111 of one of the binding areas 11, the method further comprises:

[0155] The side wall away from the second center axis of the first pin 2111 is a first side wall 4, and the side wall away from the second center axis of the first conductive part 1111 corresponding to the first pin 2111 is a second side wall 5. The distance between the first side wall 4 and the second side wall 5 in the first direction is less than half the width of the first pin 2111, and the first direction is the width direction of the first pin.

[0156] Specifically, as shown in Figure 15 and Figure 16 After the pre-shrunk circuit board 2 is bound and connected to the display panel 1, the distance between the first side wall 4 and the second side wall 5 in the first direction (i.e., the alignment offset amount of the first pin 2111 and the first conductive part 1111) is less than half the width of the first pin 2111, which indicates that the pre-shrunk size control of the pre-shrunk circuit board 2 is very accurate, and the alignment offset amount after binding is small, fully meeting the requirements of alignment binding.

[0157] In some embodiments, a vehicle-mounted "U"-shaped large FPC binding process structure is further discussed by specific embodiments, as shown in Figure 17 .

[0158] When the large FPC (i.e., the circuit board 2) is bound to the glass substrate (i.e., the display panel 1), the binding process of a single binding part 21 is the same as that of a common small-size FPC. The FPC binding part 21 directly contacts the high-temperature hot press head 6 of the equipment, the hot press head 6 rapidly heats and pressurizes the FPC binding part 21, and the FPC in the binding area 11 has a thickness of only 0.07 mm and expands rapidly under heat.

[0159] There is a conductive adhesive layer 3 (referred to as ACF) under the FPC, and the binding area 11 on the glass substrate below the ACF. The conductive part 111 of the binding area 11 is made on the glass substrate (the thickness of the vehicle-mounted substrate is generally 0.25-0.5 mm).

[0160] During the hot pressing process, the conductive adhesive balls under pressure are crushed, and the conductive liquid after the crushing of the adhesive balls is connected to form a conductive layer. The more the number of crushed conductive balls, the larger the area of the conductive layer, and the more reliable the connection between the pin 211 of the FPC and the conductive part 111 of the glass substrate, and the better the electrical conductivity.

[0161] The thickness of the display panel 1 is much thicker than that of the FPC. During the hot pressing process, the heat transfer sequence of the high-temperature hot press head 6 is: the hot press head 6 down knife → FPC substrate → FPC pin 211 → ACF → conductive part 111 → single glass substrate. When the heat is transferred to the glass substrate, the heat is already very small, and the temperature of the glass substrate basically has no change, so the glass substrate does not expand.

[0162] In some embodiments, a pre-shrinking method for improving the binding accuracy of a vehicle-mounted "U"-shaped large FPC is further discussed by specific embodiments, as shown in Figure 18

[0163] The pre-shrinking method includes two pre-shrinking directions: a first pre-shrinking direction and a second pre-shrinking direction

[0164] The first pre-shrinking direction: the effective pin (i.e., the first pin 2111) of the gold finger of the single binding part 21 of the FPC is pre-shrunk from both ends to the center of the binding part 21;

[0165] The second pre-shrinking direction: the left binding part A and the right binding part B of the FPC are pre-shrunk to the center (Centerling L0)

[0166] I. Pre-shrinking ratio calculation:

[0167] (I) Pre-shrinking ratio of the first pre-shrinking direction (hereinafter referred to as "direction one"):

[0168] 1. Direction one expansion amount calculation:

[0169] The pre-shrinking ratio depends on the actual production line binding hot pressing temperature, which is generally set to 180-190°C. Because the hot pressing head is relatively long, the temperature of the hot pressing head lower knife (contact surface with the FPC) is only about 75°C. The FPC expansion calculation is as follows: a = ΔL / (L x ΔT)

[0170] Wherein:

[0171] a: FPC wire expansion coefficient, for example, the expansion coefficient of the FPC binding part 21 is 16-18 ppm / °C.

[0172] △L: expansion amount after temperature change

[0173] L: length dimension affected by temperature change

[0174] △T: temperature change value, the binding process is the temperature rise value, △T = hot pressing head lower knife temperature - normal temperature ≈ 75-25 ≈ 50°C

[0175] ∴△L = a x △T x L = (16-18 ppm / °C) x 50°C x L = (8E-4-9E-4) x L

[0176] Therefore, the expansion amount of the single binding part 21 is 0.0008-0.0009 of the length (i.e., 0.0008-0.0009).

[0177] 2. Direction one pre-shrinking ratio:

[0178] ​The pre-shrinking ratio of the FPC single binding part 21 is consistent with the actual binding expansion, that is, the length size of the FPC before binding needs to be pre-shrunk. The binding conditions of different devices are different. Exemplarily, the pre-shrinking ratio in direction one is 0.0008-0.001 (i.e. 0.0008-0.001).

[0179] (II) The pre-shrinking ratio in the second pre-shrinking direction (hereinafter referred to as "direction two")

[0180] 1. Direction two expansion amount calculation:

[0181] Since the adjacent binding parts of the "U"-shaped large FPC are disconnected in the middle, the temperature of the hot press head during binding is directly transmitted to the binding part, and the heat of other areas outside the FPC binding part is conducted from the binding part in the FPC substrate. When the heat is transmitted to the lower part of the binding area of the substrate, the substrate will expand after being heated, and the expansion at this place will cause the FPC pins to move to the left and right outer sides.

[0182] The FPC shape, material and structure of different projects are different, and the expansion amount of the lower part of the FPC binding area has no fixed ratio, and there will be some differences due to different projects.

[0183] To obtain the specific expansion amount, process test verification needs to be performed to determine the change amount ΔD of the center distance of the adjacent binding parts before and after binding 12 , as shown in Figure 19 and Figure 20 .

[0184] ΔD 12 = D' 12 - D 12

[0185] ΔD 12 : Change amount of center distance of adjacent binding parts before and after binding

[0186] D 12 : Center distance of binding part A-binding part B before binding

[0187] D' 12 : Center distance of binding part A-binding part B after binding

[0188] Process test verification: make more than 20 samples, measure D 12 , D' 12 average value, and get ΔD 12 .

[0189] Then, the direction two expansion coefficient a2 = ΔD 12 / D 12 .

[0190] 2. Direction two pre-shrinking ratio:

[0191] From the process test verification results, the expansion coefficient of direction two is obtained, and the effective Pin first Pin to the effective Pin tail Pin size P of FPC can be calculated total The pre-shrinking ratio of the total pitch P total after pre-shrinking is obtained, which is composed of different pre-shrinking ratios of multiple segments, as shown in Figure 21

[0192] P total : the total pitch of the first Pin to the tail Pin of FPC before pre-shrinking;

[0193] P total : the total pitch of the first Pin to the tail Pin of FPC after pre-shrinking;

[0194] ∵P total = T A + D 12 + T B , T A pre-shrinking ratio = direction one pre-shrinking ratio (exemplarily, eight to ten ten-thousandths), D 12 pre-shrinking ratio = a2 = △D 12 / D 12 , T B pre-shrinking ratio = T A pre-shrinking ratio;

[0195] ∴Pˊ total = (T A -T A × direction one pre-shrinking ratio) + (D 12 -D 12 × a2) + (T B -T B × direction one pre-shrinking ratio) = P total – (T A × direction one pre-shrinking ratio) – (D 12 × a2) – (T B × direction one pre-shrinking ratio).

[0196] Two, a size calculation for improving the binding and positioning accuracy of a vehicle-mounted "U"-shaped large FPC, as shown in Figure 22

[0197] ①Pre-shrinking direction one size T pitch1 , T pitch2 calculation

[0198] FPC single binding part pre-shrinking size:

[0199] T pitch1 , T pitch2 ​​Total pitch of the gold finger of the single binding part from the first effective pin to the Nth effective pin (Pitch means distance or size)

[0200] T pitch1 = T pitch2 = P 1～N (Center distance of the effective pin 1 to the effective pin N on the glass) - P 1～N × Direction one pre-shrinking ratio. Exemplarily, the direction one pre-shrinking ratio is eight ten-thousandths (0.0008), thus Tpitch1 = T pitch2 = P 1～N -P 1～N × 0.0008.

[0201] Suppose that P 1～N = 34.2 mm has been determined, then T pitch1 = T pitch2 = 34.2 - 34.2 × 0.0008 = 34.1726 mm.

[0202] 2. Pre-shrinking direction two size P' total calculation

[0203] P' total = P total - (T A × Direction one pre-shrinking ratio) - (D 12 × a2) - (T B × Direction one pre-shrinking ratio).

[0204] P total : Total pitch of the FPC before pre-shrinking from the effective first pin to the effective tail pin;

[0205] P' total : Total pitch of the FPC after pre-shrinking from the effective first pin to the effective tail pin;

[0206] T A : Distance from the first effective pin of the binding part A to the center line L1 of the binding part A on the glass;

[0207] T A = T B = 1 / 2 × P 1～N ;

[0208] D 12 : Center distance of the binding part A - the binding part B before binding;

[0209] Expansion coefficient a2: Pre-shrinking ratio of the pre-shrinking direction two size D12, which is valued according to the actual project process verification result. Exemplarily, the expansion coefficient a2 is generally below three ten-thousandths.

[0210] III. Effective head Pin and tail Pin offset tolerance calculation

[0211] (I) Effective head Pin and tail Pin center offset δ1, δ2 tolerance

[0212] The maximum FPC offset occurs on the effective head Pin and tail Pin on the left and right outer sides. First, calculate the center offset δ1 (left binding part effective head Pin) and δ2 (right binding part effective tail Pin) of the first pin of the FPC and the first conductive part on the glass substrate, see Figure 23 .

[0213] δ1 = δ2 = C1 - C 1tft = C2 - C 2tft , C1 = C2 = (P mark -P' total ) / 2

[0214] Where:

[0215] δ1: The center offset of the effective head Pin of the FPC (i.e. the first pin on the left end) and the corresponding conductive part;

[0216] δ2: The center offset of the effective tail Pin of the FPC (i.e. the first pin on the right end) and the corresponding conductive part;

[0217] C1: The distance from the effective head Pin of the FPC to the left outer side Mark of the FPC (i.e. the second alignment structure), with a tolerance of ±0.02 mm in general and ±0.015 mm in the best case;

[0218] C2: The distance from the effective tail Pin of the FPC to the right outer side Mark of the FPC, with a tolerance of ±0.02 mm in general and ±0.015 in the best case;

[0219] C 1tft : The distance from the effective head Pin pad of the glass substrate (i.e. the first conductive part on the left end) to the left outer side Mark of the glass (i.e. the first alignment structure), with a tolerance of ±0.004 mm;

[0220] C 2tft : The distance from the effective tail Pin pad of the glass substrate (i.e. the second conductive part on the left end) to the right outer side Mark of the glass (i.e. the first alignment structure), with a tolerance of ±0.004 mm;

[0221] P mark : The center distance of the left and right outer side Marks of the FPC (i.e. the second alignment structure), which is the same as the center distance of the Marks on the corresponding glass substrate (i.e. the first alignment structure);

[0222] Pˊ total : The total pitch of the effective head Pin to the effective tail Pin after the FPC is pre-shrunk.

[0223] ∴δ1=δ2=(C1±0.015)-(C 1tft ±0.004)=(C2±0.015)-(C 2tft ±0.004)=(C1-C 1tft )±0.019=(C2-C 2tft )±0.019mm.

[0224] The effective first Pin and the tail Pin center offset δ1, δ2 tolerance can be ±0.019mm.

[0225] (II) The offset tolerance A of the effective first Pin, tail Pin pin and conductive part dev1 , A dev2 , see Figure 24 .

[0226] A dev1 =A dev2 =W / 2+δ1-W pad / 2; wherein,

[0227] A dev1 : the offset distance of the effective first Pin of the FPC and the corresponding first conductive part;

[0228] A dev2 : the offset distance of the effective tail Pin of the FPC and the corresponding first conductive part;

[0229] W: the width of the effective Pin pin of the FPC, with a tolerance of ±0.02mm;

[0230] δ1: the center offset of the effective first Pin of the FPC and the corresponding first conductive part;

[0231] W pad : the width of the first conductive part of the glass effective Pin, with a tolerance of ±0.002mm;

[0232] ∴A dev1 =W / 2+δ1-W pad / 2=(W±0.02) / 2+(δ1±0.019)+(W pad ±0.002) / 2=(W / 2±0.01)+(δ1±0.019)+(W pad / 2±0.001)=(W / 2+δ1-W pad / 2)±0.03mm

[0233] Therefore, the offset tolerance of the effective first and tail Pins of the FPC is ±0.03mm, that is, after the FPC design adopts appropriate pre-shrinking and pre-shrinking ratio, the FPC pin can be accurately aligned with the glass conductive part in the binding heat expansion, and the offset fluctuation can be controlled within ±30um.

[0234] Vehicle-mounted glass Pad pitch ≥0.16mm, the width (W) of the gold finger in the FPC design is half of the pitch, that is, W≥0.08mm,

[0235] The offset max 30um≤1 / 2W, so the FPC binding offset meets the specifications.

[0236] Four, a vehicle-mounted "U" shaped large FPC binding Mark grabbing method and size control, see Figure 25 .

[0237] Based on the above pre-shrinkage design, the process needs to be grabbed in the following way Mark, to ensure that the binding alignment fluctuation is minimum.

[0238] Mark grabbing method:

[0239] When binding, the camera grabbing Mark has two, preferentially grabbing the left outer Mark A and the right outer Mark D.

[0240] Size control:

[0241] According to the above pre-shrinkage design, the following sizes and tolerances need to be controlled:

[0242] (1) P total : the total pitch of the effective first Pin to the effective tail Pin after the FPC pre-shrinkage;

[0243] (2) C1, C2: the distance from the effective first and tail Pin of the FPC to the center of the left and right outer Mark of the FPC;

[0244] (3) P mark : the distance between the left and right outer centers of the FPC;

[0245] (4) T pitch1 , T pitch2 : the total pitch of the first effective Pin to the Nth effective Pin of the gold finger of a single binding part;

[0246] (5) M1, M2: the total pitch of the effective Pin of a single binding part.

[0247] In this application, in view of the serious offset problem of the "U" shaped large FPC binding on the glass substrate, a new method for improving the alignment accuracy is proposed, which can greatly improve the alignment accuracy, effectively increase the ACF conductive glue ball area and the total number of conductive ball particles, improve the electrical conductivity, production yield and FPC connection reliability, and greatly reduce the production cost.

[0248] The distance between the "U"-shaped large FPC left and right outer side marks and the size tolerance are controlled, the fluctuation range of the capture alignment marks during the small collection and binding is captured, and the alignment accuracy is improved.

[0249] The FPC single binding part is expanded after being heated on the glass, and the FPC is pre-shrunk in advance. The total distance from the leftmost to the rightmost effective pin of the FPC is obtained from the process, the actual data after binding is determined, the expansion coefficient relative to the FPC center is determined, and then the pre-shrinking ratio of the FPC is calculated.

[0250] The size tolerance of the single segment FPC alignment mark to the nearest pin is controlled, and the offset fluctuation of the left and right outer side pins can be reduced.

[0251] The pre-shrinking ratio of the binding part obtained by different FPC substrate materials, shapes and structures is different, and the pre-shrinking ratio of the specific project can be accurately calculated through the process verification result.

[0252] The application also provides a display device, comprising the display module of any of the above embodiments.

[0253] The display device can be a product with image display function, for example, it can be a display, a television, a billboard, a digital photo frame, a laser printer with display function, a telephone, a mobile phone, a personal digital assistant (PDA), a digital camera, a camcorder, a viewfinder, a navigator, a vehicle, a large-area wall, a household appliance, an information query device (such as an electronic government affairs, a bank, a hospital, a power department business query device, a monitor, etc.).

[0254] The display device has the technical effects of any of the above embodiments, which will not be repeated here.

[0255] It should be noted that some embodiments of the application have been described above. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recited in the claims can be performed in a different order than those described above and still achieve desirable results. In addition, the processes depicted in the figures do not necessarily require the particular order shown or sequential order to achieve the desired results. In certain implementations, multitasking and parallel processing can be advantageous.

[0256] Those skilled in the art will understand that the discussion of any of the above embodiments is merely exemplary and is not intended to limit the scope of the application to these examples; under the idea of the application, the above embodiments or technical features in different embodiments can also be combined, the steps can be implemented in any order, and there are many other changes of different aspects of the embodiments of the application as described above. In order to be brief, they are not provided in detail.

[0257] Embodiments of the present application are intended to cover any and all such substitutions, modifications, and variations. Accordingly, any one of the above-described embodiments of the present application can be replaced by any other disclosed embodiments of the present application, and the entirety of any disclosed series can be substituted for any other disclosed series, and the entirety of any disclosed series can be substituted for any other disclosed series, and the entirety of any disclosed series can be substituted for any other disclosed series, and the entirety of any disclosed series can be substituted for any other disclosed series, and the entirety of any disclosed series can be substituted for any other disclosed series, and the entirety of any disclosed series can be substituted for any other disclosed series, and the entirety of any disclosed series can be substituted for any other disclosed series, and the entirety of any disclosed

Claims

1. A display module, characterized by The display panel is provided with at least two binding areas, each of which comprises a plurality of conductive parts arranged at intervals. The circuit board comprises at least two binding parts arranged at intervals, each of which comprises a plurality of pins arranged at intervals, and each of the plurality of pins of each of the binding parts corresponds to and is connected to a plurality of conductive parts of a binding area. The distance between the first central axis of the first pin of each of the binding parts and the second central axis of the binding part is a first distance, the distance between the third central axis of the first conductive part of the binding area corresponding to the first pin of the binding part and the fourth central axis of the binding area is a second distance, the first pin is a pin of the plurality of pins farthest from the second central axis, the first conductive part is a conductive part corresponding to the first pin, and the ratio of the difference between the second distance and the first distance to the second distance is a first pre-shrinking ratio. The distance between the second central axes of two adjacent binding parts is a third distance, the distance between the fourth central axes of two adjacent binding areas is a fourth distance, and the ratio of the difference between the fourth distance and the third distance to the fourth distance is a second pre-shrinking ratio. The first pre-shrinking ratio is greater than the second pre-shrinking ratio. The distance P' between the first central axes of the first pins of two adjacent binding parts is calculated according to the following formula:

2. The display module of claim 1, wherein, The first pre-shrinking ratio is 0.0008-0.001, and the second pre-shrinking ratio is 0.0001-0.0003. P' = P - (T 21 ×m1) - (D × m2) - (T 22 ×m1); wherein P is a distance between the third center axes of the first conductive portions of the two adjacent binding areas, T 21 is the second distance of one of the two adjacent binding areas, T 22 is the second distance of the other of the two adjacent binding areas, m1 is the first pre-shrinkage ratio, D is a fourth distance, and m2 is the second pre-shrinkage ratio.

3. The display module of claim 1, wherein, Each of the binding parts further comprises at least two alignment pins, and the at least two alignment pins are respectively located on two sides of the plurality of pins.

4. The display module of claim 1, wherein, Each of the binding areas further comprises at least two first alignment structures, and the at least two first alignment structures are respectively located on a side of each of the alignment conductive parts farthest from the fourth central axis.

5. The display module of claim 4, wherein, Each of the binding parts further comprises at least two second alignment structures, and the at least two second alignment structures are respectively located on a side of each of the alignment pins farthest from the second central axis, and each of the second alignment structures corresponds to a first alignment structure. The display panel is provided with at least two binding areas, each of which comprises a plurality of conductive parts arranged at intervals, wherein the distance between the third central axis of the first conductive part of the binding area and the fourth central axis of the binding area is a second distance, and the distance between the fourth central axes of two adjacent binding areas is a fourth distance.

6. A method for manufacturing a display module, characterized by, The first pre-shrinking ratio and the second pre-shrinking ratio of the circuit board are determined, the first pre-shrinking ratio is greater than the second pre-shrinking ratio, and the circuit board comprises at least two binding parts arranged at intervals, each of which comprises a plurality of pins arranged at intervals. Based on the first pre-shrinking ratio, the second pre-shrinking ratio, the second distance and the fourth distance, the pre-shrunk size of the circuit board is determined to obtain a pre-shrunk circuit board. ​ ​ Each of the binding parts of the pre-shrunk circuit board is aligned with a binding area of the display panel and is connected by a hot-pressing process, so that the plurality of pins of each of the binding parts correspond to and are connected with the plurality of conductive parts of the binding area.

7. The production method according to claim 6, characterized by, The pre-shrunk size of the circuit board is determined based on the first pre-shrunk ratio, the second pre-shrunk ratio, the second distance, and the fourth distance, including: The first distance between the first center axis of the first pin of each of the binding parts of the circuit board and the second center axis of the binding part, and the distance between the first center axes of the first pins of two adjacent binding parts are determined based on the first pre-shrunk ratio, the second pre-shrunk ratio, the second distance, and the fourth distance, to determine the pre-shrunk size of the circuit board.

8. The production method according to claim 7, characterized by, The first distance between the first center axis of the first pin of each of the binding parts of the circuit board and the second center axis of the binding part, including: The product of the second distance and the first pre-shrunk ratio is determined as the pre-shrunk distance; The difference between the second distance and the pre-shrunk distance is determined as the first distance.

9. The preparation method according to claim 7, characterized in that The distance between the first center axes of the first pins of two adjacent binding parts, including: The distance P' between the first center axis of the first pin of the adjacent two binding parts is calculated according to the following formula: P' = P - (T 21 ×m1) - (D × m2) - (T 22 ×m1); wherein P is a distance between the third center axes of the first conductive portions of the two adjacent binding areas, T 21 is the second distance of one of the two adjacent binding areas, T 22 is the second distance of the other of the two adjacent binding areas, m1 is the first pre-shrinkage ratio, D is a fourth distance, and m2 is the second pre-shrinkage ratio.

10. The method of claim 7, wherein, Each of the binding parts of the pre-shrunk circuit board is aligned with a binding area of the display panel and is connected by a hot-pressing process, so that the plurality of pins of each of the binding parts correspond to and are connected with the plurality of conductive parts of the binding area. Each of the binding parts is aligned with a binding area so that the fifth center axis between two adjacent binding parts at least partially overlaps with the sixth center axis between the corresponding two adjacent binding areas; Each of the binding parts is connected with a binding area by a hot-pressing process.

11. The method of claim 10, wherein, Each of the binding parts further includes at least two alignment pins, and at least two alignment conductive parts are further included in each of the binding areas. Each of the binding areas further includes at least two first alignment structures, and each of the alignment conductive parts further includes at least two second alignment structures. Each of the binding parts further includes at least two second alignment structures, and each of the second alignment structures corresponds to a first alignment structure. The alignment of each of the binding parts with a binding area, including: Each of the second alignment structures is aligned with a first alignment structure, and each of the alignment pins of the binding part is aligned with the alignment conductive part of the corresponding binding area, so that each of the binding parts is aligned with a binding area.

12. The method of claim 11, wherein, The connection of each of the binding parts with a binding area by a hot-pressing process, including: An electrically conductive adhesive layer is arranged between the binding part and the binding area; After the binding part and the binding area are heated to a preset temperature, the binding part and the binding area are pressed at a preset pressure, so that the plurality of pins of each of the binding parts correspond to and are connected with the plurality of conductive parts of the binding area.

13. The preparation method according to claim 7, characterized in that In the method, each of the binding portions of the pre-shrunk circuit board is aligned with a binding area of the display panel, and then is connected by a hot-pressing process, so that the plurality of pins of each of the binding portions are one-to-one corresponding to and connected with the plurality of conductive portions of the binding area. The side wall of the first pin away from the second central axis is a first side wall, and the side wall of the first conductive portion corresponding to the first pin away from the second central axis is a second side wall, the distance between the first side wall and the second side wall in the first direction is less than half of the first pin width, and the first direction is the width direction of the first pin.

14. A display device comprising: The display module prepared by the preparation method of any one of claims 6-13 or the display module of any one of claims 1-5.

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