Display module and electronic device

Abstract

The display module comprises a touch display panel, a chip on film, a driving circuit board, and a display module. The chip on film comprises a first output end and a second output end. The driving circuit board comprises a flexible circuit board and a rigid circuit board. The first output end is connected to the touch display panel, and the second output end is connected to the flexible circuit board. The display module uses the combination of the flexible circuit board and the rigid circuit board, and the shorter joint spacing between the flexible circuit board and the chip on film, so that the chip on film can have more pin arrangements without increasing the size, and more pins are reserved for the touch display panel. The high reliability of the rigid circuit board enables the touch display panel to be implemented in larger size products without increasing the cost.

Description

Technical Field

[0001] This disclosure relates to the field of display technology, and in particular to a display module and an electronic device. Background Technology

[0002] With the increasing popularity of touch displays, more and more devices are using them to provide users with more convenient operation, especially for medium and large-sized electronic devices such as in-vehicle infotainment screens, laptops, and even televisions. As FMLOC (Flexible Multiply Layer on Cell) technology matures, it is gradually expanding from small-sized consumer products like mobile phones to in-vehicle products and even laptops and televisions. However, in practical applications, the emitter and receiver electrodes (TX and RX) of FMLOC technology occupy too many pins on the output terminals of the chip-on-film (COF). Due to limitations in current pin fabrication processes, it is impossible to implement FMLOC touch functionality on medium and large-sized display panels, or the only solution is to widen the COF to increase the number of pins, leading to increased costs. Summary of the Invention

[0003] The purpose of this disclosure is to provide a display module and an electronic device to solve the problem that the limitations of the manufacturing process in the prior art make it impossible to realize FMLOC or increase costs.

[0004] The embodiments of this disclosure adopt the following technical solution: a display module, comprising: a touch display panel; a flip-chip film, the flip-chip film including at least a first output terminal and a second output terminal disposed opposite to each other; a driving circuit board, the driving circuit board including at least a flexible circuit board and a rigid circuit board; wherein, the first output terminal is connected to the touch display panel, and the second output terminal is connected to the flexible circuit board.

[0005] In some embodiments, the second output terminal includes at least a first overlap region, the first overlap region including at least a plurality of first pins arranged sequentially along a first direction; the flexible circuit board includes at least a second overlap region, the second overlap region including at least a plurality of second pins arranged sequentially along the first direction; wherein, the first bonding spacing in the first overlap region is the same as the second bonding spacing in the second overlap region, and both the first bonding spacing and the second bonding spacing are greater than or equal to 120 micrometers; the first bonding spacing is the sum of the spacing between two adjacent first pins and the width of the first pin, and the second bonding spacing is the sum of the spacing between two adjacent second pins and the width of the second pin.

[0006] In some embodiments, the touch display panel includes at least a touch function layer and a display function layer, wherein the touch function layer is disposed on the light-emitting side of the display function layer.

[0007] In some embodiments, the pins in the first overlap area and the second overlap area are each divided into a first number of display driving pins and a second number of touch driving pins; at least one touch chip is arranged on the rigid circuit board, the output terminal of the touch chip is connected to the touch driving pin in the second overlap area, and the touch driving pin in the second overlap area is connected to the touch functional layer via the touch driving pin in the first overlap area and the first output terminal.

[0008] In some embodiments, a timing control chip is also disposed on the rigid circuit board, and at least a display driver chip is disposed on the flip-chip film; the output terminal of the timing control chip is connected to the display driver chip via the display driver pin in the second overlap area, and the output terminal of the display driver chip is connected to the display functional layer via the first output terminal.

[0009] In some embodiments, the rigid circuit board and the flexible circuit board are electrically connected based on a metal trace layer, and the metal trace layer is disposed on the same layer as the second pin.

[0010] In some embodiments, the touch display panel is a flexible multilayer embedded touch display panel.

[0011] In some embodiments, the second quantity is greater than or equal to 80.

[0012] In some embodiments, the touch display panel is 10 inches or larger.

[0013] This disclosure also provides an electronic device, which includes at least the display module described above.

[0014] The beneficial effects of the embodiments disclosed herein are as follows: by using a combination of flexible circuit boards and rigid circuit boards, and by utilizing the shorter bonding gap that can be achieved between the flexible circuit board and the flip-chip film, the flip-chip film can be arranged with more pins without increasing its size, thus reserving more pins for the display of touch functions. At the same time, combined with the high reliability of the rigid circuit board, the touch display panel can be implemented in larger-sized products without increasing costs. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of this disclosure or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram illustrating the connection between the display panel and the driver circuit board in a conventional design.

[0017] Figure 2 This is a schematic diagram of the joint spacing;

[0018] Figure 3 This is a schematic diagram showing the connection status of the display module in the first embodiment of this disclosure;

[0019] Figure 4 This is a schematic diagram of the cross-sectional layers of the flexible circuit board and the rigid circuit board in the first embodiment of this disclosure;

[0020] Figure 5 This is a dimensional design diagram of the first output terminal and the second output terminal in a conventional flip-chip film according to the first embodiment of this disclosure. Detailed Implementation

[0021] Various embodiments and features of this disclosure are described herein with reference to the accompanying drawings.

[0022] It should be understood that various modifications can be made to the embodiments described herein. Therefore, the above description should not be considered as limiting, but merely as an example of embodiments. Other modifications within the scope and spirit of this disclosure will be apparent to those skilled in the art.

[0023] The accompanying drawings, which are included in and form part of this specification, illustrate embodiments of the present disclosure and, together with the general description of the disclosure given above and the detailed description of the embodiments given below, serve to explain the principles of the disclosure.

[0024] These and other features of this disclosure will become apparent from the following description of preferred forms of embodiments given as non-limiting examples, with reference to the accompanying drawings.

[0025] It should also be understood that although this disclosure has been described with reference to some specific examples, many other equivalent forms of this disclosure can be definitively implemented by those skilled in the art, which have the features of the claims and are therefore within the scope of protection defined herein.

[0026] The above and other aspects, features and advantages of this disclosure will become more apparent when taken in conjunction with the accompanying drawings and in view of the following detailed description.

[0027] Specific embodiments of this disclosure are described thereafter with reference to the accompanying drawings; however, it should be understood that the claimed embodiments are merely examples of this disclosure, which may be implemented in various ways. Well-known and / or repeated functions and structures are not described in detail to avoid unnecessary or redundant details that could obscure this disclosure. Therefore, the specific structural and functional details claimed herein are not intended to be limiting, but merely to serve as the basis and representative basis for the claims to teach those skilled in the art to use this disclosure in a variety of substantially any suitable detailed structures.

[0028] This specification may use the phrases “in one embodiment,” “in another embodiment,” “in yet another embodiment,” or “in still another embodiment,” all of which may refer to one or more of the same or different embodiments according to this disclosure.

[0029] With the increasing popularity of touchscreen displays, more and more devices are using them to provide users with more convenient operation, especially large and medium-sized electronic devices such as in-vehicle infotainment screens, laptops, and even televisions. As FMLOC (Flexible Multiply Layer on Cell) technology matures, it is gradually expanding from small-sized consumer products like mobile phones to in-vehicle products and even laptops and televisions. However, when FMLOC technology is applied to COF solutions, the traces for its transmitting and receiving electrodes (TX and RX) will occupy the bypass pins on the output terminals (ILB / OLB) of the COF (i.e., the pins in the ILB / OLB other than those used for the display panel driver). For specific connection details, please refer to [reference needed]. Figure 1 As shown ( Figure 1 The pins are not shown in the text, only the connection is indicated by arrows); this will lead to the following problems: (1) If FMLOC technology is implemented, it will cause the bonding pitch (bonding pitch, i.e. the sum of the width of a single pin and the spacing between adjacent pins, such as) of the ILB / OLB terminals of the COF. Figure 2 (1) As shown in the figure) becomes smaller; (2) Due to the precision limitation of the factory bonding equipment, the minimum joint spacing between the COF and the PCB (printed circuit board) can only be 240 micrometers. Considering the bonding process and yield, the number of pins reserved for TX and RX on the COF cannot meet the requirements for touch function implementation; (3) If FMLOC technology is to be implemented, the width of the COF can only be increased physically while the joint spacing remains unchanged. However, this will lead to a significant increase in cost and will not be advantageous for product design.

[0030] To address the aforementioned problems, the first embodiment of this disclosure provides a display module, such as... Figure 3 As shown, the display module in this embodiment mainly includes a touch display panel 10, a crystal-coated film 20, and a driving circuit board 30. The touch display panel 10 mainly refers to a flexible multilayer embedded touch display panel, that is, a touch-enabled display panel based on FMLOC technology. This panel has at least a touch function layer and a display function layer. The touch function layer is usually located on the light-emitting side of the display function layer. Combining the characteristics of FMLOC, the touch function layer is embedded between the color filter and polarizer in the OLED panel to reduce the overall thickness of the touch display panel 10. The flip-chip film 20 is a die-film assembly technology that fixes integrated circuits on a flexible circuit board. In this embodiment, it mainly arranges a display driver chip (SDIC) to realize the driving control of the display function layer. The flip-chip film 20 mainly includes a first output terminal and a second output terminal, which are used to connect the touch display panel 10 and the driving circuit board 30, respectively. The driving circuit board 30 is mainly used to arrange the various chips that drive the touch display panel, including but not limited to timing control chips (T-con, time controller, not shown in the figure), touch chips (TIC, touchIC), and other functional chips. It may also include other components such as power supply and testing.

[0031] In this embodiment, the driving circuit board 30 mainly includes a flexible circuit board 31 (FPC, in...) Figure 3 (The image shows the shaded area) and a rigid circuit board 32 (PCB); the flexible circuit board 31, due to its material, properties, and the bonding precision of the bonding equipment, can achieve a smaller bonding gap when connected to the flip-chip film 20, while the rigid circuit board 32 has high reliability and can better ensure the normal function of the display module under various conditions. Combining the two is more conducive to ensuring the use of the touch display panel in various medium and large-sized products. It should be noted that... Figure 4A cross-sectional layer diagram of the flexible circuit board 31 and the rigid circuit board 32 is shown, mainly corresponding to the approximate layer structure at their junction. It can be seen that the right side of the dashed line corresponds to the layer of the flexible circuit board 31, and the left side of the dashed line corresponds to the layer of the rigid circuit board 32. The flexible circuit board 31 and the rigid circuit board 32 are electrically connected through a metal trace layer 40. Each driving chip or component arranged on the rigid circuit board 32 can be connected to the metal trace layer 40 through vias or other means, and the metal traces in the metal trace layer 40 are used to connect to the pins in the flexible circuit board 31 to realize signal transmission. Generally speaking, the metal trace layer 40 can have an exposed part in the overlapping area of ​​the flexible circuit board 31 that can be directly used as a pin, that is, the two are set on the same layer. In actual fabrication, according to the other layer requirements of the flexible circuit board 31 and the rigid circuit board 32, different layers are fabricated in different areas of the same metal trace layer 40. For example, a flexible cover film 41 is set in the area corresponding to the flexible circuit board 31 to protect and insulate the metal traces; while in the area of ​​the metal trace layer 40 corresponding to the rigid circuit board 32, layers such as PP adhesive layer 42 and top green paint 43 are set to meet the hardness requirements of this area and improve safety. It should be noted that... Figure 4 This is only a partial cross-sectional schematic of the flexible circuit board 31 and the rigid circuit board 32. In actual fabrication, the specific layer design and the thickness of each layer can be achieved according to requirements.

[0032] Specifically, the second output terminal of the flip-chip film 20 is connected to the flexible circuit board 31, and its first output terminal is connected to the touch display panel 10, thereby enabling the transmission of drive signals from various components on the rigid circuit board 32 to the touch display panel 10. Corresponding to the connection between the flip-chip film 20 and the flexible circuit board 31, the second output terminal includes at least a first overlap area, within which at least a plurality of first pins are arranged sequentially along a first direction. Correspondingly, the flexible circuit board 31 has a second overlap area, within which at least a plurality of second pins are arranged sequentially along the first direction. The number of first pins and the number of second pins can be the same or different, as long as the number after overlap meets the functional requirements of the touch display panel. Furthermore, the first overlap area has a first joint spacing in the design implementation, and the second overlap area has a corresponding second joint spacing. The first joint spacing and the second joint spacing should be the same to ensure the overlap effect between the first pin and the second pin. The size of their spacing should be at least greater than or equal to 120 micrometers. The first joint spacing is the sum of the spacing between two adjacent first pins and the width of the first pin, and the second joint spacing is the sum of the spacing between two adjacent second pins and the width of the second pin.

[0033] This embodiment addresses the issue of insufficient pin count caused by the limited bonding spacing between COF and PCB in conventional designs. It replaces the COF-connected circuit board with an FPC circuit board. Existing manufacturing processes can achieve a minimum bonding spacing of 120 micrometers, allowing for a larger number of pins while maintaining the same physical width of the COF. This provides more pins for touch functionality while keeping the number of pins required for display functions constant, enabling touch functionality on larger display panels. This benefits product development and user experience. Furthermore, widening the COF is significantly more expensive than replacing the PCB with an FPC-PCB combination, allowing for product manufacturing at a lower cost. It is important to note that the touch display panel addressed in this embodiment primarily refers to medium to large-sized display panels with a size of 10 inches or larger. For applications in automotive products, laptops, or televisions, users have specific requirements regarding the usage environment and lifespan of these devices. Therefore, while the connection between the flexible circuit board and the chip-on-film allows for touch functionality in medium to large-sized products, it is not recommended to use the flexible circuit board alone as the driver circuit board. Firstly, the manufacturing cost of flexible circuit boards is relatively high, and medium to large-sized products require even larger flexible circuit boards, which is not conducive to reducing production costs. Secondly, flexible circuit boards have lower safety and shorter lifespan compared to rigid PCBs, making them unsuitable for automotive environments. Therefore, this embodiment employs a combination of flexible and rigid circuit boards to achieve higher product safety while minimizing cost increases, and simultaneously fulfilling the touch functionality requirements for medium to large-sized display products.

[0034] In some embodiments, the pins in both the first and second overlap areas are divided into a first number of display driver pins and a second number of touch driver pins, respectively used to transmit display driver signals and touch driver signals. The display driver pins in the first and second overlap areas are overlapped, and the touch driver pins in the first and second overlap areas are overlapped to ensure correct signal transmission. Corresponding to the timing control chip arranged on the rigid circuit board 32 and the display driver chip arranged on the flip-chip 20, the output terminal of the timing control chip is connected to the display driver pins in the second overlap area, and timing signal transmission with the display driver chip is achieved via the display driver pins in the first overlap area. The display driver chip then outputs display driver signals to the display function layer through its first output terminal according to the timing signal control, thereby realizing the display function. Corresponding to the touch chip arranged on the rigid circuit board 32, its output terminal is connected to the touch driver pins in the second overlap area, so that its output touch driver signals are connected to the touch function layer via the touch driver pins in the first overlap area and the first output terminal, thereby realizing the touch function.

[0035] It should be understood that this embodiment does not limit the position of the display driver pins and touch driver pins in the first and second overlap areas, as long as proper signal connectivity is ensured. Specific settings can be determined by referring to the arrangement of each component, the location and size of the flip-chip film, the size of the touch display panel, and other specific conditions; this embodiment does not impose any limitations. However, the number of display driver pins and touch driver pins should at least ensure the normal implementation of both display and touch functions. Specifically, the first number of display driver pins is usually set according to the size, resolution, and size of the flip-chip film of the display panel. For example, for conventional flip-chip films and 17-inch OLED displays, the number of pins used to implement the display function on the second output end of each flip-chip film is at least 214. The second number of touch driver pins also needs to be set according to the size, resolution, and size of the flip-chip film of the display panel, while also taking into account the accuracy requirements of the touch function. Currently, for FMLOC touch display panels, at least 40 TX traces and 40 RX traces should be designed to meet the normal touch function implementation. Therefore, the second number of touch driver pins should be at least greater than or equal to 80 to meet the actual touch requirements.

[0036] Figure 5 The dimensions of the first and second output terminals in a conventional flip-chip film are shown. The width of the first output terminal is 61.2 mm and the width of the second output terminal is 55.7 mm. For conventional display panels, in products that do not require touch functionality, the first number of display driver pins in the second output terminal is 214, and the corresponding first bonding pitch is 55.7 / 214≈260um. However, for the FLMOC project, the second output terminal needs to have at least 294 pins, that is, 80 touch driver pins are added on the basis of the above display driver pins. The corresponding first bonding pitch is 55.7 / 294≈190um. However, the default minimum bonding pitch between COF and PCB is 240um, that is, a maximum of 55.7 / 240≈232 can be set. Therefore, the number of TX and RX traces reserved is 232-214=18, which is completely insufficient to meet the requirements for touch functionality. Corresponding to the driver circuit board design in this embodiment, the minimum bonding distance between COF and FPC can be 120um. Without increasing the width of COF, the total number of pins can be approximately 464 (55.7 / 120). The number of TX and RX traces reserved is 464-214=250, which can fully meet the requirements for touch functionality. Furthermore, as the number of available pins in FMLOC increases, it can directly affect the design of the display panel size, thereby supporting larger touch solutions.

[0037] This embodiment uses a combination of flexible and rigid circuit boards. By utilizing the shorter bonding gap between the flexible circuit board and the flip-chip film, more pins can be arranged on the flip-chip film without increasing its size, reserving more pins for touch display functions. At the same time, combined with the high reliability of the rigid circuit board, the touch display panel can be implemented in larger-sized products without increasing costs.

[0038] The second embodiment of this disclosure provides an electronic device, which mainly refers to medium and large-sized products such as in-vehicle central control screens, laptops, and televisions with display panels of 10 inches or larger. The electronic device is equipped with at least a display module as provided in the first embodiment of this disclosure. By utilizing the shorter bonding gap that can be achieved between the flexible circuit board and the flip-chip film, more pins can be arranged on the flip-chip film without increasing its size, reserving more pins for the touch display function. At the same time, combined with the high reliability of the rigid circuit board, the touch display panel can be implemented in larger-sized products without increasing the cost.

[0039] The foregoing has provided a detailed description of several embodiments of this disclosure. However, this disclosure is not limited to these specific embodiments. Those skilled in the art can make various variations and modifications based on the concept of this disclosure, and all such variations and modifications should fall within the scope of protection claimed by this disclosure.

Claims

1. A display module, characterized in that, include: Touch display panel; A flip-chip film, wherein the flip-chip film includes at least a first output terminal and a second output terminal disposed opposite to each other; A driving circuit board, the driving circuit board comprising at least a flexible circuit board and a rigid circuit board; The first output terminal is connected to the touch display panel, and the second output terminal is connected to the flexible circuit board. The flexible circuit board and the rigid circuit board are electrically connected through a metal trace layer. The driver chip or component arranged on the rigid circuit board is connected to the metal trace layer through vias, and the various metal traces in the metal trace layer are used to connect to the various pins in the flexible circuit board to realize signal transmission. The flexible circuit board and the rigid circuit board can be fabricated at different levels in different areas of the same metal trace layer.

2. The display module according to claim 1, characterized in that, The second output terminal includes at least a first overlap area, and the first overlap area includes at least a plurality of first pins arranged sequentially along a first direction; The flexible circuit board includes at least a second overlapping area, and the second overlapping area includes at least a plurality of second pins arranged sequentially along the first direction; Wherein, the first joint spacing in the first overlap area is the same as the second joint spacing in the second overlap area, and both the first joint spacing and the second joint spacing are greater than or equal to 120 micrometers; the first joint spacing is the sum of the spacing between two adjacent first pins and the width of the first pin, and the second joint spacing is the sum of the spacing between two adjacent second pins and the width of the second pin.

3. The display module according to claim 2, characterized in that, The touch display panel includes at least a touch function layer and a display function layer, wherein the touch function layer is disposed on the light-emitting side of the display function layer.

4. The display module according to claim 3, characterized in that, The pins in both the first and second overlapping areas are divided into a first number of display driver pins and a second number of touch driver pins; At least one touch chip is arranged on the rigid circuit board. The output terminal of the touch chip is connected to the touch driving pin in the second overlap area. The touch driving pin in the second overlap area is connected to the touch functional layer via the touch driving pin in the first overlap area and the first output terminal.

5. The display module according to claim 4, characterized in that, A timing control chip is also arranged on the rigid circuit board, and at least a display driver chip is arranged on the flip-chip film. The output terminal of the timing control chip is connected to the display driver chip via the display driver pin in the second overlap area, and the output terminal of the display driver chip is connected to the display function layer via the first output terminal.

6. The display module according to claim 4 or 5, characterized in that, The rigid circuit board and the flexible circuit board are electrically connected based on a metal trace layer, which is disposed on the same layer as the second pin.

7. The display module according to claim 4, characterized in that, The touch display panel is a flexible multi-layer embedded touch display panel.

8. The display module according to claim 4, characterized in that, The second quantity is greater than or equal to 80.

9. The display module according to any one of claims 1 to 8, characterized in that, The touch display panel has a size greater than or equal to 10 inches.

10. An electronic device, characterized in that, It includes at least the display module as described in any one of claims 1 to 8.

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