CN113611213A

CN113611213A - Chip on film and display device

Info

Publication number: CN113611213A
Application number: CN202110874120.4A
Authority: CN
Inventors: 刘常富; 康报虹
Original assignee: HKC Co Ltd
Current assignee: HKC Co Ltd
Priority date: 2021-07-30
Filing date: 2021-07-30
Publication date: 2021-11-05
Anticipated expiration: 2041-07-30
Also published as: CN113611213B

Abstract

The application discloses chip on film and display device, chip on film includes flexible substrate, driver chip, many input signal lines and many output signal lines, arbitrary one the output signal line all includes first output line and second output line that not direct connection, first output line with driver chip is connected, the second output line along the extending direction of first output line towards the direction of keeping away from driver chip extends; the chip on film comprises a plurality of resistors, the resistors are in one-to-one correspondence with the output signal lines, one ends of the resistors are connected with the first output lines, and the other ends of the resistors are connected with the second output lines. Through the design, the load of the circuit corresponding to each output line number line is improved, so that redundant current in the circuit is consumed by the resistor, the load current of the driving chip is reduced to a great extent, and the high-temperature problem of the driving chip caused by large current is avoided.

Description

Chip on film and display device

Technical Field

The application relates to the technical field of display, in particular to a chip on film and a display device.

Background

With the continuous development of integrated circuit technology, electronic products are gradually developing toward miniaturization and high reliability. As the performance of Integrated Circuits (ICs) is directly affected by the packaging of the ICs, the requirements for packaging the ICs are higher and higher under the condition that the size of the IC chip is gradually reduced and the integration level is continuously improved. An IC (driver Chip) for driving a display panel needs a high-density packaging technology, and a Chip On Film (COF) package is a commonly used packaging form at present. Because the driving chip is directly bonded on the flexible film (such as a flexible circuit board) in the chip on film packaging, the frame area of the display panel is not required to be occupied, and the narrow frame structure is easier to realize.

The refresh rate and the resolution of the display screen are higher and higher, so that the power consumption of the display screen is increased, the temperature of a driving chip on the display screen is increased, and the temperature of the driving chip is required to be reduced in order to ensure that the chip can normally operate; therefore, designing a flip chip on film that avoids the high temperature problem is an important research topic in the industry.

Disclosure of Invention

The present application provides a flip chip on film and a display device that do not generate high temperature.

The application discloses a chip on film, which comprises a flexible substrate, a driving chip, a plurality of input signal lines and a plurality of output signal lines, wherein the input signal lines, the output signal lines and the driving chip are arranged on the flexible substrate, one end of the driving chip is connected with the input signal lines to receive signals, and the other end of the driving chip is connected with the output signal lines to output signals; any one of the output signal lines comprises a first output line and a second output line which are not directly connected, the first output line is connected with the driving chip, and the second output line extends along the extending direction of the first output line towards the direction far away from the driving chip; the chip on film comprises a plurality of resistors, the resistors are in one-to-one correspondence with the output signal lines, one ends of the resistors are connected with the first output lines, and the other ends of the resistors are connected with the second output lines.

Optionally, the resistor is a winding resistor.

Optionally, the winding resistor and the output signal line are formed through the same process.

Optionally, the adjacent winding resistors are arranged in a staggered manner.

Optionally, the resistor is a chip resistor.

Optionally, the plurality of chip resistors are divided into a first chip group and a second chip group, and the first chip group and the second chip group both include a plurality of chip resistors; the flexible substrate comprises a substrate front side and a substrate back side which are oppositely arranged, the first patch group and the output signal line are arranged on the substrate front side, and the second patch group is arranged on the substrate back side; one end of any one of the chip resistors in the first chip group is connected with the first output line, and the other end of the chip resistor is connected with the corresponding second output line; one end of any one chip resistor in the second chip set penetrates through the flexible substrate through a metal wire and is connected with the first output line, and the other end of the chip resistor penetrates through the flexible substrate through the metal wire and is connected with the second output line; any one of the chip resistors in the first chip set is located between two adjacent chip resistors in the second chip set.

Optionally, two adjacent patch resistors in the first patch group are arranged in a staggered manner, and two adjacent patch resistors in the second patch group are arranged in a staggered manner.

Optionally, the plurality of output signal lines are sequentially arranged at intervals along the width direction of the chip on film, and the resistance values of the resistors corresponding to the output signal lines are gradually reduced from the middle of the chip on film to both sides of the chip on film in the width direction of the chip on film.

Optionally, the resistor corresponding to each output signal line is formed by connecting at least two sub-resistors in series.

The application also discloses a display device, which comprises the chip on film, a display panel and a control circuit board; one end of the chip on film is connected with the control circuit board, the other end of the chip on film is connected with the display panel, and a driving chip in the chip on film receives a voltage signal in the control circuit board through an input signal line, converts the voltage signal into a driving signal, and inputs the driving signal into the display panel through an output signal line so as to drive the display panel.

This application passes through each first output line of ohmic connection and second output line, makes each output signal line in the cover brilliant film all insert a resistance, improves the load of each output signal line corresponding circuit, makes unnecessary electric current consumed by the resistance in the circuit, thereby has reduced the carrier current of each output signal line in the cover brilliant film, and then has reduced driver chip's carrier current to a great extent, has avoided driver chip because the high temperature problem that heavy current leads to.

Drawings

The accompanying drawings, which are included to provide a further understanding of the embodiments of the application, are incorporated in and constitute a part of this specification, illustrate embodiments of the application and together with the description serve to explain the principles of the application. It is obvious that the drawings in the following description are only some embodiments of the application, and that for a person skilled in the art, other drawings can be derived from them without inventive effort. In the drawings:

fig. 1 is a schematic diagram of a display device according to a first embodiment of the present application;

fig. 2 is a schematic plan view of a first chip on film according to a first embodiment of the present disclosure;

FIG. 3 is a schematic plan view of a second chip on film according to the first embodiment of the present application;

FIG. 4 is a schematic plan view of a third chip on film according to the first embodiment of the present application;

FIG. 5 is a schematic plan view of a first chip on film according to a second embodiment of the present application;

fig. 6 is a schematic cross-sectional view of a chip on film according to a second embodiment of the present application;

fig. 7 is a schematic plan view of a second chip on film according to a second embodiment of the present application.

100, a display device; 200. a chip on film; 210. a flexible substrate; 211. a substrate front side; 212. a back side of the substrate; 220. a driving chip; 230. an input signal line; 240. an output signal line; 241. a first output line; 242. a second output line; 250. a resistance; 251. winding a resistor; 252. a chip resistor; 253. a sub-resistance; 260. a first patch group; 270. a second patch group; 300. a display panel; 400. and a control circuit board.

Detailed Description

It is to be understood that the terminology, the specific structural and functional details disclosed herein are for the purpose of describing particular embodiments only, and are representative, but that the present application may be embodied in many alternate forms and should not be construed as limited to only the embodiments set forth herein.

In the description of the present application, the terms "first", "second" are used for descriptive purposes only and are not to be construed as indicating relative importance or as implicitly indicating the number of technical features indicated. Thus, unless otherwise specified, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature; "plurality" means two or more. The terms "comprises" and "comprising," and any variations thereof, are intended to cover a non-exclusive inclusion, such that one or more other features, integers, steps, operations, elements, components, and/or combinations thereof may be present or added.

Further, terms of orientation or positional relationship indicated by "center", "lateral", "upper", "lower", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like, are described based on the orientation or relative positional relationship shown in the drawings, are simply for convenience of description of the present application, and do not indicate that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present application.

Furthermore, unless expressly stated or limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly and may include, for example, fixed connections, removable connections, and integral connections; can be mechanically or electrically connected; either directly or indirectly through intervening media, or through both elements. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art as appropriate.

The present application is described in detail below with reference to the figures and alternative embodiments.

The first embodiment is as follows:

fig. 1 shows a schematic diagram of a display device according to a first embodiment of the present application, as shown in fig. 1, the display device 100 includes a chip on film 200, a display panel 300 and a control circuit board 400, one end of the chip on film 200 is connected to the control circuit board 400, and the other end is connected to the display panel 300, a driving chip 220 in the chip on film 200 receives a voltage signal in the control circuit board 400 through an input signal line 230, converts the voltage signal into a driving signal, and inputs the driving signal into the display panel 300 through an output signal line 240 to drive the display panel 300. The driving Chip 220(IC) in the Chip On Film (COF) 200 may be a Gate driving Chip (Gate IC) or a Source driving Chip (Source IC), and the control Circuit Board 400 is a Printed Circuit Board (PCB).

As shown in fig. 2, the chip on film 200 includes a flexible substrate 210, a driving chip 220, a plurality of input signal lines 230 and a plurality of output signal lines 240, wherein the plurality of input signal lines 230, the plurality of output signal lines 240 and the driving chip 220 are disposed on the flexible substrate 210, and one end of the driving chip 220 is connected to the plurality of input signal lines 230 to receive signals, and the other end is connected to the plurality of output signal lines 240 to output signals; any one of the output signal lines 240 includes a first output line 241 and a second output line 242 which are not directly connected, the first output line 241 is connected with the driving chip 220, and the second output line 242 extends along the extending direction of the first output line 241 towards the direction far away from the driving chip 220; the chip on film 200 includes a plurality of resistors 250, the plurality of resistors 250 correspond to the plurality of output signal lines 240 one by one, and one end of each resistor 250 is connected to the first output line 241, and the other end is connected to the corresponding second output line 242.

The impedance of the display panel is related to the thickness of the metal film in the manufacturing process, the display panel determines the thickness of the film according to the process, the effect and the like, once the thickness of the film is fixed, the impedance is basically fixed, if the thickness of the film is larger, the load (panel Loading) of the display panel is larger, so that the temperature of the chip on film 200 is higher, and if the thickness of the metal film is changed, other manufacturability problems or the problem of non-uniform display picture (mura) may be brought. In the embodiment, the load of the display panel is reduced by adding the resistor 250 to the output channel of the chip on film 200, so that the temperature of the chip on film 200 is reduced, and the process and the display picture of the display panel are not influenced; each first output line 241 and each second output line 242 are connected through a resistor 250, so that each output signal line 240 in the chip on film 200 is connected to one resistor 250, the load of a circuit corresponding to each output signal line is increased, redundant current in the circuit is consumed by the resistor 250, the load current of each output signal line 240 in the chip on film 200 is reduced, the load current of the driving chip 220 is further reduced to the greatest extent, and the problem of high temperature of the driving chip 220 caused by large current is avoided.

At present, the problem of heat generation in the chip on film 200 is mostly solved by a simple method of attaching a heat dissipation paste, but the heat dissipation method causes about 20% of cost increase, and a special process needs to be added, and the attaching of the heat dissipation paste causes various problems such as warping or glue overflow. The present embodiment is based on the improvement of the internal circuit structure in the flip chip package 200, and avoids the heat generation of the driving chip 220 in the flip chip package 200 by increasing the load of the output signal line 240 in the flip chip package 200, so as to solve the heat generation problem of the flip chip package 200 at the source; for wait the chip after generating heat, the scheme that the chip problem of generating heat was solved to the mode of attached heat dissipation subsides of rethread, circuit loss, the poor scheduling problem of chip work efficiency that leads to when this embodiment has avoided the chip to generate heat have still avoided adopting the warpage that the heat dissipation pasted and lead to or overflow multiple problems such as gluing.

In this embodiment, the resistor 250 is a winding resistor 251. Since each output signal line 240 needs to be connected with one resistor 250, the present embodiment utilizes the characteristics of small size and low cost of the winding resistor 251 to connect the winding resistor 251 with the first output line 241 and the second output line 242, thereby avoiding the contact short circuit of the winding resistor 251 in two adjacent output signal lines 240. Specifically, the winding resistor 251 and the output signal lines 240 may be formed through the same process, that is, when the output signal lines 240 are manufactured, each output signal line 240 is designed to have a pattern in which two ends are straight lines and a middle portion is an S-shaped curve or other shape curves; the straight line portions at both ends of the output signal line 240, i.e., the first output line 241 and the second output line 242, and the curved line portion in the middle of the output signal line 240, i.e., the winding resistor 251. Because the existence of the winding resistor 251, the length of the output signal line 240 is increased, and the resistance formula shows that the longer the output signal line 240 is, the larger the resistance value is, the winding resistor 251 can increase the resistance value of the output signal line 240, so that the consumption of current in the circuit is increased, and the driving chip 220 is prevented from generating heat to cause high temperature.

As shown in fig. 3, adjacent ones of the winding resistors 251 are offset. When it is necessary to increase the resistance of the winding resistor 251 to further increase the current consumption in the circuit, a method is to increase the number of winding turns of the winding resistor 251, so as to further increase the length of the winding resistor 251 in the direction of the output signal line 240; another method is to increase the width of the winding resistors 251, but this will compress the space between the adjacent winding resistors 251, so that the adjacent winding resistors 251 are easy to contact and short-circuit, therefore, in this embodiment, the adjacent winding resistors 251 are arranged in a staggered manner, so that the adjacent winding resistors 251 are not in the same straight line, and the short-circuit problem caused by increasing the width of the winding resistors 251 is avoided. It should be noted that fig. 3 only provides a staggered arrangement of the winding resistors 251, and the winding resistors 251 may also be arranged in other staggered arrangements, which are not listed here. Of course, the winding resistor 251 can be made of a high-resistance material in this embodiment, so as to increase the resistance of the winding resistor 251, and the winding resistor 251 and the output signal line 240 are not formed by the same process; after the first output line 241 and the second output line 242 are manufactured, the winding resistor 251 may be bonded or welded between the first output line 241 and the second output line 242.

Because the driving chip 220 in the chip on film 200 is connected with the fan-out wires in the display panel, and then transmits the driving signals to the display panel, one end of the fan-out wires is connected with the data lines or the scanning lines in the display panel, and the other end is connected with the output signal lines 240 in the chip on film 200, the output signal lines 240 are densely distributed, and the data lines or the scanning lines are more scattered; therefore, the width of the end, connected with the display panel, of the fan-out area is large, and the width of the end, connected with the chip on film 200, of the fan-out area is small, so that the fan-out wires from the middle to the two sides in the fan-out area are longer and longer, the longer the fan-out wires are, the larger the resistance of the fan-out wires is, and the problem of uneven resistance of the wires in the fan-out area is solved.

Based on this, as shown in fig. 4, in the present embodiment, the winding resistors 251 in each of the flip-chip packages 200 are set to have different resistances, specifically, in the flip-chip packages 200, the output signal lines 240 are sequentially arranged at intervals along the width direction of the flip-chip packages 200, and in the width direction of the flip-chip packages 200, that is, the arrangement direction of the output signal lines 240; from the middle of the chip on film 200 to both sides of the chip on film 200, the resistance of the resistor 250 corresponding to the output signal line 240 gradually decreases. At this time, the sum of the resistance values of the resistor 250 corresponding to each output signal line 240 and the corresponding fan-out wiring is approximately equal, so that it is ensured that the driving signal received by the display panel does not generate large fluctuation, and the stability of the display image is improved. Furthermore, the resistance of the winding resistor 251 can be gradually reduced by gradually reducing the number of turns of the winding resistor 251 from the middle of the flip chip 200 to the two sides of the flip chip 200. Of course, the resistance of the routing resistor 251 can also be changed by changing the number or size of the sub-resistors by making the routing resistor 251 corresponding to each of the output signal lines 240 into the resistor 250 formed by connecting a plurality of sub-resistors in series.

Example two:

fig. 5 shows a schematic plan view of a chip on film 200 according to a second embodiment of the present disclosure, which is different from the first embodiment in that the resistor 250 in the present embodiment is a chip resistor 252, so that after the chip on film 200 is initially manufactured, an appropriate resistor 250 can be selected according to the heating condition of the driving chip 220 and the type of the display panel, thereby increasing the application range of the chip on film 200.

As shown in fig. 5 and fig. 6, the number of the chip resistors 252 in each chip on film 200 is equal to the number of the output signal lines 240, all the chip resistors 252 in each chip on film 200 are divided into a first chip set 260 and a second chip set 270, and each of the first chip set 260 and the second chip set 270 includes a plurality of chip resistors 252; the flexible substrate 210 comprises a substrate front surface 211 and a substrate back surface 212 which are oppositely arranged, the first patch group 260 and the output signal line 240 are arranged on the substrate front surface 211, and the second patch group 270 is arranged on the substrate back surface 212; one end of any one of the chip resistors 252 in the first chip group 260 is connected to the first output line 241, and the other end is connected to the corresponding second output line 242; one end of any one of the chip resistors 252 in the second chip group 270 penetrates through the flexible substrate 210 through a metal wire and is connected to the first output line 241, and the other end penetrates through the flexible substrate 210 through a metal wire and is connected to the second output line 242; any one chip resistor 252 in the first chip set 260 is located between two adjacent chip resistors 252 in the second chip set 270.

Compared with the wire resistor 251, the volume of the chip resistor 252 is slightly larger, so as to avoid the short circuit caused by the contact of the chip resistors 252 connected to the adjacent output signal lines 240, or the mutual interference and the difficulty in installation, in the embodiment, all the chip resistors 252 in one flip chip 200 are respectively and uniformly arranged on the front and back surfaces of the flip chip 200, so that half the number of the chip resistors 252 can be arranged on the front and back surfaces of the flip chip 200, and the installation space of the chip resistors 252 is greatly increased. Moreover, any one of the chip resistors 252 in the first chip set 260 is located between two adjacent chip resistors 252 in the second chip set 270, that is, the chip resistors 252 and the corresponding output signal lines 240 are located on the same straight line, and on each surface of the chip on film 200, the chip resistors 252 corresponding to the output signal lines 240 between the adjacent chip resistors 252 are all located on the other surface of the chip on film 200, so that the chip resistors 252 on each surface of the chip on film 200 are uniformly spaced, which facilitates the alignment installation of the chip resistors 252.

Further, two adjacent chip resistors 252 in the first chip set 260 are arranged in a staggered manner, and two adjacent chip resistors 252 in the second chip set 270 are arranged in a staggered manner. In the embodiment, the chip resistors 252 on one flip chip 200 are arranged on the front and back sides of the flip chip 200, and the chip resistors 252 on each side of the flip chip 200 are arranged in a staggered manner, so that the distance between two adjacent chip resistors 252 on the front or back side of the flip chip 200 is further increased; thus, when the chip resistor 252 with a larger resistance is selected, even if the chip resistor 252 with a larger resistance has a larger volume, the chip resistor is mounted in the flip chip 200 with a larger accommodating space and will not contact with the adjacent chip resistor 252.

Because the fan-out in the fan-out district is walked the line from middle to fan-out of both sides and is lengthened more and more, the fan-out is walked the line and can lead to the fan-out to walk the resistance of line bigger more, therefore the line of fan-out district has the inhomogeneous problem of resistance. Therefore, in the present embodiment, the chip resistors 252 in each of the flip chips 200 are set to have different resistance values, so that the sum of the resistance values of the resistors 250 corresponding to each of the output signal lines 240 and the corresponding fan-out traces is approximately equal, thereby ensuring that the driving signals received by the display panel do not generate large fluctuation, and improving the stability of the display image. As shown in fig. 7, the chip resistor 252 corresponding to each of the output signal lines 240 is formed by connecting at least two sub-resistors 253 in series; from the middle of the chip on film 200 to both sides of the chip on film 200, the number of the sub-resistors 253 in the chip resistor 252 is gradually reduced or the resistance of the sub-resistors 253 is gradually reduced.

Because the specification of the resistors 250 on the market is uniform, the larger the resistance of the resistor 250 is, the larger the resistance of the resistor 250 on one order of magnitude is, and the difference between the two resistances is also large, so that it is difficult to find out a plurality of resistors 250 with gradually slightly changing resistances, therefore, in this embodiment, the chip resistor 252 corresponding to one output signal line 240 is made into a plurality of sub-resistors 253, when the required resistance of the chip resistor 252 is relatively close, if a single resistor 250 with a close resistance cannot be found, the plurality of resistors 250 can be selected to be connected in series to form the required resistor 250, thereby better meeting the use requirements. Of course, it is also possible to connect a plurality of sub-resistors 253 in parallel to form the chip resistor 252, or connect a plurality of resistors 250 in series and in parallel to form the chip resistor 252 at the same time.

It should be noted that the inventive concept of the present application can form many embodiments, but the present application has a limited space and cannot be listed one by one, so that, on the premise of no conflict, any combination between the above-described embodiments or technical features can form a new embodiment, and after the embodiments or technical features are combined, the original technical effect will be enhanced

The technical solution of the present application can be widely applied to various display panels, such as TN (Twisted Nematic) display panel, IPS (In-Plane Switching) display panel, VA (Vertical Alignment) display panel, MVA (Multi-Domain Vertical Alignment) display panel, and of course, other types of display panels, such as OLED (Organic Light-Emitting Diode) display panel, and the above solution can be applied thereto.

The foregoing is a more detailed description of the present application in connection with specific alternative embodiments, and the specific implementations of the present application are not to be considered limited to these descriptions. For those skilled in the art to which the present application pertains, several simple deductions or substitutions may be made without departing from the concept of the present application, and all should be considered as belonging to the protection scope of the present application.

Claims

1. A chip on film comprises a flexible substrate, a driving chip, a plurality of input signal lines and a plurality of output signal lines, wherein the plurality of input signal lines, the plurality of output signal lines and the driving chip are arranged on the flexible substrate, one end of the driving chip is connected with the plurality of input signal lines to receive signals, the other end of the driving chip is connected with the plurality of output signal lines to output signals, and the chip on film is characterized in that,

any one of the output signal lines comprises a first output line and a second output line which are not directly connected, the first output line is connected with the driving chip, and the second output line extends along the extending direction of the first output line towards the direction far away from the driving chip;

the chip on film comprises a plurality of resistors, the resistors are in one-to-one correspondence with the output signal lines, one ends of the resistors are connected with the first output lines, and the other ends of the resistors are connected with the second output lines.

2. The chip on film of claim 1, wherein the resistor is a wire-wound resistor.

3. The chip on film of claim 2, wherein the wire wrap resistor and the output signal line are formed by the same process.

4. The chip on film of claim 2, wherein adjacent ones of the wire resistors are offset.

5. The chip on film of claim 1, wherein the resistor is a chip resistor.

6. The chip on film of claim 5, wherein the plurality of chip resistors are divided into a first chip group and a second chip group, and the first chip group and the second chip group both comprise a plurality of chip resistors;

the flexible substrate comprises a substrate front side and a substrate back side which are oppositely arranged, the first patch group and the output signal line are arranged on the substrate front side, and the second patch group is arranged on the substrate back side;

one end of any one of the chip resistors in the first chip group is connected with the first output line, and the other end of the chip resistor is connected with the corresponding second output line;

one end of any one chip resistor in the second chip set penetrates through the flexible substrate through a metal wire and is connected with the first output line, and the other end of the chip resistor penetrates through the flexible substrate through the metal wire and is connected with the second output line;

any one of the chip resistors in the first chip set is located between two adjacent chip resistors in the second chip set.

7. The chip on film of claim 6, wherein two adjacent chip resistors in the first chip set are disposed in a staggered manner, and two adjacent chip resistors in the second chip set are disposed in a staggered manner.

8. The chip on film according to any one of claims 1-7, wherein the output signal lines are sequentially arranged at intervals along the width direction of the chip on film, and the resistances of the resistors corresponding to the output signal lines are gradually reduced from the middle of the chip on film to both sides of the chip on film in the width direction of the chip on film.

9. The chip on film of claim 8, wherein the corresponding resistor of each of the output signal lines is formed by connecting at least two sub-resistors in series.

10. A display device comprising the flip-chip film according to any one of claims 1 to 9, and a display panel and a control circuit board;

one end of the chip on film is connected with the control circuit board, the other end of the chip on film is connected with the display panel, and a driving chip in the chip on film receives a voltage signal in the control circuit board through an input signal line, converts the voltage signal into a driving signal, and inputs the driving signal into the display panel through an output signal line so as to drive the display panel.