Flexible printed circuit board and display device

Abstract

A flexible printed circuit board and a display device, the flexible printed circuit board comprises a base layer, a pair of traces and a chip. The first trace is arranged on the base layer, and each trace has a first end and a second end opposite to each other. The chip is arranged on the base layer and has a plurality of pins, and these pins are respectively coupled to the first end of the first trace. When the flexible printed circuit board is connected to a panel via the second ends of these traces and the second ends of these traces are short-circuited to each other, the chip is used to transmit a detection signal via one of the pins and receive a receiving signal via another pin, and judge whether the flexible printed circuit board and the panel work normally according to the received signal. The present invention at least has the function of automatically detecting whether the flexible printed circuit board is defective.

Description

Technical Field

[0001] The present invention relates to a flexible printed circuit board, and in particular to a flexible printed circuit board with an automatic defect detection function and a display device having the flexible printed circuit board. Background Art

[0002] Recently, displays have been widely used in automotive applications, such as video playback, vehicle-related information display, traffic status notification, etc. In addition, chip-on-film technology can be applied to automotive displays to further reduce their occupied space. However, chip-on-film packages used for such automotive displays may crack due to excessive bending and / or have bonding defects. Summary of the invention

[0003] One aspect of the present invention is a flexible printed circuit board (FPC board), which includes a base layer, a pair of first traces and a chip. The first traces are arranged on the base layer, and each first trace has a first end and a second end opposite to each other. The chip is arranged on the base layer and has a plurality of first pins, and these first pins are respectively coupled to the first ends of the first traces. When the flexible printed circuit board is connected to the panel via the second ends of these first traces and the second ends of these first traces are short-circuited to each other, the chip is used to transmit a first detection signal via one of the first pins and receive a first reception signal via another first pin, and determine whether the flexible printed circuit board and the display panel are working normally based on the first reception signal.

[0004] According to one or more embodiments of the present invention, the first traces are located at the longitudinal side edges of the base layer.

[0005] According to one or more embodiments of the present invention, the first traces are respectively located at two opposite longitudinal side edges of the base layer.

[0006] According to one or more embodiments of the present invention, the flexible printed circuit board further includes a pair of second traces. These second traces are on the base layer, and each of these second traces has a first end and a second end opposite to each other. The chip also has a plurality of second pins, and these second pins are respectively coupled to the first ends of these second traces, and when the flexible printed circuit board is connected to the control board via the second ends of these second traces and the second ends of these second traces are short-circuited to each other, the chip is also used to transmit a second detection signal via one of the second pins and receive a second reception signal via another second pin, and determine whether the flexible printed circuit board works normally with the display panel and the control board based on the first reception signal and the second reception signal.

[0007] According to one or more embodiments of the present invention, the first traces and the second traces are located at the longitudinal side edges of the base layer.

[0008] According to one or more embodiments of the present invention, one of the first traces and one of the second traces are located at one longitudinal side edge of the base layer, and another of the first traces and another of the second traces are located at another longitudinal side edge of the base layer.

[0009] According to one or more embodiments of the present invention, the second detection signal is an inverted signal of the first detection signal.

[0010] According to one or more embodiments of the present invention, the chip includes a detection signal generating unit, an inverter and a test signal detecting unit. The detection signal generating unit is used to generate a first detection signal according to a synchronization signal. The inverter is used to invert the first detection signal to obtain a second detection signal. The test signal detecting unit is used to receive and process the first detection signal and the second detection signal to determine whether the flexible printed circuit board works normally with the display panel and the control board.

[0011] According to one or more embodiments of the present invention, the chip further includes an equalization unit, which is used to equalize the first detection signal and the second detection signal.

[0012] According to one or more embodiments of the present invention, the test signal detection unit includes a logic operation unit, a sampling unit and a decision unit. The logic operation unit is used to perform an exclusive-OR logic operation on the first received signal and the second received signal to obtain an identification signal. The sampling unit is used to sample the identification signal. The decision unit is used to determine whether the flexible printed circuit board works normally with the display panel and the control board based on the sampling result of the sampling unit on the identification signal.

[0013] Another aspect of the present invention is a display device, which includes a display panel, a control board and a flexible printed circuit board. The control board is used to control the display of the display panel. The flexible printed circuit board is bonded to the display panel and the control board, and includes a substrate, a chip, a pair of first traces and a pair of second traces. The chip is arranged on the substrate and has a plurality of first pins and a plurality of second pins. These first traces are arranged on the substrate, and each of these first traces has a first end and a second end opposite to each other. The first end of these first traces is coupled to the first pin of the chip, and the flexible printed circuit board is bonded to the display panel via the second end of these first traces. These second traces are arranged on the substrate, and each of these second traces has a first end and a second end opposite to each other. The first end of these second traces is coupled to the second pin of the chip, and the flexible printed circuit board is bonded to the control board via the second end of these second traces. The chip is used to transmit a first detection signal and a second detection signal respectively via one of the first pins and one of the second pins, and to receive a first reception signal and a second reception signal respectively via another first pin and another second pin, and to determine whether the flexible printed circuit board works normally with the display panel and the control board according to the first reception signal and the second reception signal.

[0014] According to one or more embodiments of the present invention, the chip is a display driver IC (DDI) or a touch and display driver integration (TDDI) chip.

[0015] According to one or more embodiments of the present invention, the display panel is a liquid crystal display panel.

[0016] According to one or more embodiments of the present invention, a control board includes a front-end video processor and a microcontroller unit (MCU).

[0017] The beneficial effect of the present invention is at least that the flexible printed circuit board of the present invention can automatically detect whether it has defects, and the display device having the flexible printed circuit board can automatically detect whether the flexible printed circuit board works normally with the display panel. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] For a more complete understanding of the embodiments and their advantages, reference is now made to the following description taken in conjunction with the accompanying drawings, in which:

[0019] Figure 1 is a simplified plan view of a display device according to an embodiment of the present invention;

[0020] Figure 2 Based on an example Figure 1 A top view of the flexible printed circuit board coupled to the display panel and the control board;

[0021] Figure 3 Based on another example Figure 1 A top view of the flexible printed circuit board coupled to the display panel and the control board;

[0022] Figure 4A Show Figure 2 A side view of a flexible printed circuit board in an unbent state;

[0023] Figure 4B Show Figure 2 A side view of a flexible printed circuit board in a bent state;

[0024] Figure 5 By way of example Figure 2 Automatic defect detection function for flexible printed circuit boards;

[0025] Figure 6 According to one or more embodiments of the present invention Figure 2 A schematic block diagram of a wafer;

[0026] Figure 7 According to an example shown Figure 6 A timing diagram showing a signal waveform associated with signal detection;

[0027] Figure 8 According to one or more embodiments of the present invention Figure 2 A schematic block diagram of a wafer;

[0028] Fig. 9 According to an example Figure 8 Timing diagram of the signal waveforms of some signals. DETAILED DESCRIPTION

[0029] The following is a detailed discussion of the embodiments of the present invention. However, it is to be understood that the embodiments provide many applicable concepts that can be implemented in a variety of specific contexts. The embodiments discussed and disclosed are for illustration only and are not intended to limit the scope of the present invention.

[0030] The terms used herein are intended only to describe specific embodiments and are not intended to limit the claims. Unless otherwise limited, the singular terms "a," "an," or "the" may also be used to refer to the plural form. In addition, the use of spatially relative terms is intended to illustrate different orientations of an element when in use or operation, and is not limited to the orientation shown in the accompanying drawings. Elements may also be oriented in other ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used herein may be interpreted in the same manner.

[0031] The following description and claims may use the term "coupled" and its derivatives. In certain embodiments, "coupled" may refer to two or more elements being in direct physical or electrical contact with each other, or not being in direct contact with each other. "Coupled" may also refer to two or more elements operating or acting on each other.

[0032] For simplicity and clarity of description, reference numerals and / or letters may be repeated in various embodiments herein, but this does not imply a causal relationship between the various embodiments and / or configurations discussed.

[0033] Figure 11 is a simplified plan view of a display device 100 according to an embodiment of the present invention. The display device 100 can be used in various applications, such as in-vehicle infotainment systems, smart wearable devices, and other applications with display functions. The display device 100 includes a display panel 110, a control board 120, and a flexible printed circuit (FPC) board 130. The display panel 110 can be, for example, a twisted nematic (TN) type, an in-plane switching (IPS) type, or any other type of liquid crystal display panel, an organic light emitting diode (OLED) panel, or any other suitable type of display panel. The display panel 110 can be flexible, and its shape can be regular (such as rectangular or circular) or irregular. The control board 120 is used to control the display of the display panel 110. For example, if the display device 100 is utilized in a vehicle infotainment system, the control board 120 may control the data and signals of the display panel 110 to display information, such as a map, a virtual dashboard image, internal / external temperature, and / or the like. The control board 120 may be a printed circuit board having, for example, a front-end video processor, a microcontroller unit (MCU), an electronic control unit (ECU), and / or other circuits / electronic components for controlling the display panel 110. The flexible printed circuit board 130 is electrically connected between the display panel 110 and the control board 120. The flexible printed circuit board 130 is flexible and bendable, so that the control board 120 may be located at the rear of the display panel 110 when the flexible printed circuit board 130 is bent, so as to further reduce the space occupied by the display device 100. Figure 1 As shown, the sections 130A and 130B of the flexible printed circuit board 130 overlap the display panel 110 and the control board 120, respectively. The flexible printed circuit board 130 is bonded to the display panel 110 and the control board 120 at the sections 130A and 130B, respectively.

[0034] Figure 2The figure is a top view of a flexible printed circuit board 130 coupled to a display panel 110 and a control board 120 according to an example. The flexible printed circuit board 130 may be a chip-on-film (COF) package, which includes a substrate 132, a chip 134, a pair of first traces 136A, 136B, and a pair of second traces 138A, 138B. The chip 134 is disposed on the substrate 132 and has first pins P1A, P1B and second pins P2A, P2B. The chip 134 may be a display driver IC (DDI), a touch and display driver integration (TDDI) chip, or other chips configured to drive the display panel 110. The first traces 136A, 136B and the second traces 138A, 138B are disposed on the substrate 132 and are respectively located on opposite sides of the chip 134. Each of the first traces 136A, 136B has opposite first and second ends. For the first trace 136A, its first end and second end are respectively coupled to the first pin P1A of the chip 134 and the conductive pad 112A of the display panel 110, while for the first trace 136B, its first end and second end are respectively coupled to the first pin P1B of the chip 134 and the other conductive pad 112B of the display panel 110. Similarly, each second trace 138A, 138B has a first end and a second end opposite to each other. For the second trace 138A, its first end and second end are respectively coupled to the second pin P2A of the chip 134 and the conductive pad 122A of the control board 120, while for the second trace 138B, its first end and second end are respectively coupled to the second pin P2B of the chip 134 and the other conductive pad 122B of the control board 120. The first traces 136A, 136B and the second traces 138A, 138B are all conductive and are formed of metals such as copper, gold, silver, aluminum, or other suitable conductive materials. In addition, as Figure 2 As shown, the first traces 136A, 136B and the second traces 138A, 138B are located at the left longitudinal side edge of the base layer 132. It should be noted that Figure 2 It may be modified so that the first traces 136A, 136B and the second traces 138A, 138B are located at the right longitudinal side edge of the base layer 132 .

[0035] Figure 3 FIG. 1 is a top view of a flexible printed circuit board 130 coupled to a display panel 110 and a control board 120 according to another example. In this example, first traces 136A and 136B are respectively located at two opposite longitudinal side edges of a base layer 132, and second traces 138A and 138B are respectively located at two opposite longitudinal side edges of a base layer 132. In particular, as Figure 3As shown, the first trace 136A and the second trace 138A are located at the left longitudinal side edge of the base layer 132 , while the first trace 136B and the second trace 138B are located at the right longitudinal side edge of the base layer 132 .

[0036] Figure 4A Show Figure 2 4, the first conductive layer 136 and the second conductive layer 138 are respectively located on both sides of the wafer 134. The first conductive layer 136 includes first traces 136A and 136B, and may also include other traces and / or electronic components (such as resistors and / or capacitors). Similarly, the second conductive layer 138 includes second traces 138A and 138B, and may also include other traces and / or electronic components.

[0037] Figure 4B FIG. 1 shows a side view of a flexible printed circuit board 130 in a bent state according to an example. Figure 4B As shown, when the flexible printed circuit board 130 is bent, the control board 120 and the chip 134 are located at the rear of the display panel 110. In particular, the portion of the base layer 132 located at the display panel 110 chip 134 is a bent portion, and the portions of the base layer 132 located at the partitions 130A, 130B and the area corresponding to the chip 134 are straight portions. In some embodiments, the portion of the base layer 132 located at the display panel 110 chip 134 is also a bent portion.

[0038] Figure 5 By way of example Figure 2The automatic defect detection function of the flexible printed circuit board 130 is provided. For the automatic defect detection function of the flexible printed circuit board 130, the chip 134 transmits the detection signals Dout1 and Dout2 through the first trace 136A and the second trace 138A, respectively, and detects the signals on the first trace 136B and the second trace 138B to determine whether the flexible printed circuit board 130 is normal. The first trace 136A and the second trace 138A are electrically connected to the first trace 136B and the second trace 138B, respectively, so that the chip 134 detects the signals corresponding to the detection signals Dout1 and Dout2 on the first trace 136B and the second trace 138B. In one example, the conductive pads 112A and 112B of the display panel 110 are short-circuited by the trace W1, and the conductive pads 122A and 122B of the control board 120 are short-circuited by the trace W2. In other examples, the traces W1 and W2 can be replaced by other electronic components (such as resistors, transistors, etc.). In this way, after the flexible printed circuit board 130 is bonded to the display panel 110 and the control board 120, when the chip 134 transmits the detection signals Dout1 and Dout2 via the first trace 136A and the second trace 138A respectively, the detection signal Dout1 becomes the receiving signal Din1 through the conductive pads 112A, 112B and the wiring W1, and the detection signal Dout2 becomes the receiving signal Din2 through the conductive pads 122A, 122B and the wiring W2.

[0039] Figure 6 FIG. 1 is a block diagram of a chip 134 according to one or more embodiments of the present invention. Figure 6 As shown, the chip 134 includes a detection signal generating unit 142, an inverter 144 and a test signal detecting unit 146. The detection signal generating unit 142 is used to generate a detection signal Dout1 according to a synchronization signal SYNC. In some embodiments, the synchronization signal SYNC can also be used to control the display of the display panel 110. In this example, the frequency of the synchronization signal SYNC is the same as the frame rate of the display panel 110. The inverter 144 is used to invert the detection signal Dout1 to obtain a detection signal Dout2 that is inverted with the detection signal Dout1. The inverter 144 can be a NOT logic gate or other suitable components. The test signal detecting unit 146 is used to receive and process the received signals Dout1 and Dout2 to determine whether the flexible printed circuit board 130 works normally with the display panel 110 and the control board 120.

[0040] In some embodiments, Figure 6As shown, the test signal detection unit 146 includes a logic operation unit 146A, a sampling unit 146B and a decision unit 146C. The logic operation unit 146A is used to perform an exclusive-OR (XOR) logic operation on the received signals Din1 and Din2 to obtain the identification signal Din. If the signal levels of the received signals Din1 and Din2 are the same (i.e., both are high level or both are low level), the signal level of the identification signal Din is a high level; conversely, if the signal levels of the received signals Din1 and Din2 are different (i.e., one is a high level and the other is a low level), the signal level of the identification signal Din is a low level. The logic operation unit 146A can be an exclusive-OR logic gate or a group of other known types of logic gates. The sampling unit 146B is used to sample the identification signal Din according to the clock signal CLK. The decision unit 146C is used to determine whether the flexible printed circuit board 130 works normally with the display panel 110 and the control board 120 based on the sampling result of the identification signal Din by the sampling unit 146B.

[0041] Figure 7 According to an example shown Figure 6 A timing diagram showing signal waveforms related to signal detection is shown. Figure 7 The waveforms of the synchronization signal SYNC, the detection signals Dout1, Dout2, the identification signal Din and the clock signal CLK within a certain duration are shown. The detection signals Dout1 and Dout2 are inverted to each other. For each cycle of the detection signals Dout1 and Dout2, the duration of the high level and the low level are substantially the same. In addition, the frequency of the clock signal CLK is substantially twice that of the synchronization signal SYNC. The identification signal Din can be sampled at the time corresponding to the rising edge of the clock signal CLK. If the sampling levels of the identification signal Din are all high, it is determined that the flexible printed circuit board 130, the display panel 110 and the control board 120 are working normally. On the contrary, if at least one sampling level of the identification signal Din is a low level (for example, some Figure 7 If the sampling value of the dotted waveform is low level, the flexible printed circuit board 130 is judged to be abnormal. It should be noted that the sampling position of the identification signal Din can be changed according to each embodiment, such as the falling edge of the clock signal CLK or each time between the adjacent rising edge and falling edge, and is not limited to Figure 7 Draw content.

[0042] In some embodiments, in addition to the first pins P1A, P1B and the second pins P2A, P2B, the chip 134 further has an abnormality notification pin, which is used to notify the abnormality of the flexible printed circuit board 130. For example, if it is determined that the operation of the flexible printed circuit board 130 is abnormal, the chip 134 can transmit a warning signal to the control board 120 via the abnormality notification pin.

[0043] Figure 8 FIG. 1 is a block diagram of a chip 134 according to one or more embodiments of the present invention. Figure 6 The block diagram shown in Figure 8 In addition to the detection signal generating unit 142, the inverter 144 and the test signal detecting unit 146, the chip 134 further includes an equalizing unit 148, which is used to equalize the detection signals Dout1 and Dout2 to obtain the first equalized detection signal Dout1' and the second equalized detection signal Dout2' with smoother waveforms, so that the chip 134 outputs the first equalized detection signal Dout1' and the second equalized detection signal Dout2' instead of the detection signals Dout1 and Dout2 through the first pin P1A and the second pin P2A respectively. If the waveforms of the detection signals Dout1 and Dout2 are square waves, the equalizing unit 148 is used to round off the sharp rising edge and the sharp falling edge of the square wave. The frequency of the synchronization signal SYNC can be 60 Hz, and the equalizing unit 148 can be used to equalize the detection signals Dout1 and Dout2 to reduce electromagnetic interference (EMI).

[0044] Fig. 9 According to an example Figure 8 The timing diagram of the synchronization signal SYNC, the detection signal Dout1, the first equalized detection signal Dout1', the detection signal Dout2 and the second equalized detection signal Dout2'. Fig. 9 It can be seen that after the equalization processing of the equalization unit 148, the signal level of each of the first and second equalized detection signals Dout1', Dout2' rises and falls more smoothly, so as to reduce the electromagnetic radiation caused by the sharp rising edge and the sharp falling edge of the original detection signals Dout1, Dout2.

[0045] Although the present invention has been disclosed as above by way of embodiments, it is not intended to limit the present invention. Any person having ordinary knowledge in the technical field may make some changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be determined by the scope defined in the attached claims.

Claims

1. A flexible printed circuit board, characterized in that: Include: A grass-roots level; A pair of first traces disposed on the base layer, each of the first traces having a first end and a second end opposite to each other; a pair of second traces disposed on the base layer, each of the second traces having a first end and a second end opposite to each other; and A chip is disposed on the base layer and has a plurality of first pins and a plurality of second pins, wherein the first pins are respectively coupled to the first ends of the first traces, and the second pins are respectively coupled to the first ends of the second traces; When the flexible printed circuit board is connected to a display panel via the second ends of the first traces and the second ends of the first traces are short-circuited, the chip is used to transmit a first detection signal via one of the first pins and receive a first reception signal via another of the first pins, and when the flexible printed circuit board is connected to a control board via the second ends of the second traces and the second ends of the second traces are short-circuited, the chip is also used to transmit a second detection signal via one of the second pins and receive a second reception signal via another of the second pins, and determine whether the flexible printed circuit board works normally with the display panel and the control board based on the first reception signal and the second reception signal.

2. The flexible printed circuit board according to claim 1, characterized in that: The first traces are located at a longitudinal side edge of the base layer.

3. The flexible printed circuit board according to claim 1, characterized in that: The first traces are respectively located at two opposite longitudinal side edges of the base layer.

4. The flexible printed circuit board according to claim 1, characterized in that: The first traces and the second traces are located at a longitudinal side edge of the base layer.

5. The flexible printed circuit board according to claim 1, characterized in that: One of the first traces and one of the second traces are located at a longitudinal side edge of the base layer, and another of the first traces and another of the second traces are located at another longitudinal side edge of the base layer.

6. The flexible printed circuit board according to claim 1, characterized in that: The second detection signal is an inverted signal of the first detection signal.

7. The flexible printed circuit board according to claim 1, characterized in that: The chip contains: a detection signal generating unit, used for generating the first detection signal according to a synchronization signal; an inverter, used for inverting the first detection signal to obtain the second detection signal; as well as A test signal detection unit is used to receive and process the first detection signal and the second detection signal to determine whether the flexible printed circuit board works normally with the display panel and the control board.

8. The flexible printed circuit board according to claim 7, characterized in that: The chip also includes: An equalization unit is used for equalizing the first detection signal and the second detection signal.

9. The flexible printed circuit board according to claim 7, characterized in that: The test signal detection unit comprises: a logic operation unit, used for performing a mutually exclusive or logic operation on the first received signal and the second received signal to obtain an identification signal; a sampling unit, used for sampling the identification signal; and A decision unit is used to determine whether the flexible printed circuit board works normally with the display panel and the control board based on the sampling result of the identification signal by the sampling unit.

10. A display device, characterized in that: Include: a display panel; a control panel for controlling the display of the display panel; and A flexible printed circuit board is bonded to the display panel and the control board, and the flexible printed circuit board comprises: A grass-roots level; a chip disposed on the substrate and having a plurality of first pins and a plurality of second pins; A pair of first traces disposed on the base layer, each of the first traces having a first end and a second end opposite to each other, wherein the first ends of the first traces are coupled to the first pins of the chip, and the flexible printed circuit board is bonded to the display panel via the second ends of the first traces; as well as A pair of second traces disposed on the base layer, each of the second traces having a first end and a second end opposite to each other, wherein the first ends of the second traces are coupled to the second pins of the chip, and the flexible printed circuit board is bonded to the control board via the second ends of the second traces; The chip is used to transmit a first detection signal and a second detection signal through one of the first pins and one of the second pins, respectively, and receive a first reception signal and a second reception signal through another one of the first pins and another one of the second pins, respectively, and determine whether the flexible printed circuit board works normally with the display panel and the control board based on the first reception signal and the second reception signal.

11. The display device according to claim 10, characterized in that: The first traces and the second traces are located at a longitudinal side edge of the base layer.

12. The display device according to claim 10, characterized in that: One of the first traces and one of the second traces are located at a longitudinal side edge of the base layer, and another of the first traces and another of the second traces are located at another longitudinal side edge of the base layer.

13. The display device according to claim 10, characterized in that: The second detection signal is an inverted signal of the first detection signal.

14. The display device according to claim 10, characterized in that: The chip contains: a detection signal generating unit, configured to generate the first detection signal according to a synchronization signal; and An inverter is used to invert the first detection signal to obtain the second detection signal.

15. The display device according to claim 14, characterized in that: The chip also includes: An equalization unit is used for equalizing the first detection signal and the second detection signal.

16. The display device according to claim 14, characterized in that: The chip also includes: a logic operation unit, used for performing a mutually exclusive or logic operation on the first received signal and the second received signal to obtain an identification signal; a sampling unit, used for sampling the identification signal; and A decision unit is used to determine the bonding result of the flexible printed circuit board to the display panel and the control board based on the sampling result of the identification signal by the sampling unit.

17. The display device according to claim 10, characterized in that: The chip is a display driver chip or a touch display driver integrated chip.

18. The display device according to claim 10, characterized in that: The display panel is a liquid crystal display panel.

19. The display device according to claim 10, characterized in that: The control board includes a front-end video processor and a microcontroller unit.

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