LED panel and operation method, LCD display and backlight and driving method

Abstract

The LED panel has an interleaved topology, where two adjacent LED rows in the LED panel are driven by different drivers. A delay time can be implemented between the start times of the two adjacent LED rows. Such an LED panel can be used in an LCD display to backlight the LCD panel. Implementing a delay time when driving the LED panel can reduce visual artifacts in the LCD display.

Description

[0001] Related Applications

[0002] This application claims priority under 35 U.S.C. §119 to U.S. Provisional Application No. 63 / 063,918, filed on August 10, 2020, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present invention provides an LED panel with a staggered topology structure and an LCD display using the staggered LED panel to provide backlight illumination for the LCD panel, as well as specific methods for arranging and operating such LED panel and LCD display. Background Art

[0004] Liquid crystal displays (LCDs) can use LED panels for backlighting. One of the drawbacks of LCDs is their slow response time, which is related to the time it takes for an LCD pixel to reach a stable voltage after being turned on. In addition, the LCD pixels in an LCD panel are turned on sequentially, so that a full frame time is required to update all LCD pixels on the display, introducing additional delay.

[0005] A 4K liquid crystal television panel (i.e., 4K LCD panel) can be used as an example to illustrate traditional backlighting methods and problems and related issues. A 4K LCD panel has 2160 rows of LCD pixels, each row has 3840 LCD pixels, and therefore the LCD panel has 3840×2160 LCD pixels. Since LCD pixels have a small size, it is not feasible to use one LED pixel to backlight one LCD pixel due to cost and size limitations. A common practice is to use a group of 4 LEDs connected in series (hereinafter referred to as an "LED group") to backlight 24×24 LCD pixels (hereinafter referred to as a "24×24 LCD group" or "LCD group"). Note that an LED group can have more or less than 4 LEDs, and an LCD group can have more or less than 24x24 LCDs.

[0006] A 4K LCD panel with 2160 rows of LCD pixels can be divided into 90 rows of different LCD groups, i.e., 2160 / 24=90 rows of LCD. Each row contains 160 LCD groups (3840 / 24=160), and a corresponding row contains 160 LED groups. Note that an LCD row can contain more than 90 LCD groups or less than 90 LCD groups. The LCD rows and their corresponding LED rows can have approximately the same footprint and are aligned with each other in a direction perpendicular to the LCD panel.

[0007] The pixels on the LCD panel are updated sequentially based on the video input. For example, the top LCD row on the LCD panel is updated first and the bottom LCD row is updated last. The update time for all the pixels on the LCD panel varies based on the frame rate, LCD panel size, LED group size, and LCD group size on the LCD panel. At a frame rate of 120Hz (frame time of 8.333ms), it takes approximately 92.5μs (8333μs / 90 rows) of frame time for all the LCD pixels on the 90 LCD rows to update on a full 4K LCD panel.

[0008] In addition, each LCD pixel requires a certain response time (T response ) to become stable. Response time (T response ) can be in the range of 1ms to 7ms, or even higher. LCD also has a hold time (T hold ), during which the image displayed on the LCD is stable. It is advisable to use the LED backlight only during its hold time. Typical hold time (T hold ) is 1.333 milliseconds.

[0009] Most LCD panels use global backlighting, where all LED groups are powered on and emit light at the same time. However, because LCD rows are updated sequentially, global backlighting can cause visual artifacts such as motion blur when different LCD rows are in different stages of updating. In addition, since the LEDs are lit before the LCD is stable, some of the LED energy is wasted. In addition, global backlighting also increases the load on the LED backlight driver because all LED groups are turned on at the same time, which requires a lot of resources.

[0010] Light emitting diodes (LEDs) have their own limitations. One of them is that the maximum current that can be driven with good efficiency is limited to, for example, only 40mA. Another limitation is the resolution of the PWM pulse width. The smaller the pulse width increment, the more difficult it is to accurately control it on a large LED array with long PCB traces. Therefore, it is desirable to have a longer PWM pulse per scan so that the maximum brightness of the LED can be higher at the maximum current allowed by the LED, and the longer PWM pulse also enables a wider pulse width increment step.

[0011] Therefore, there is a need for an LED panel that operates under less stringent conditions in terms of drive current, PWM pulse width, etc. It is also desirable to provide dynamic LED backlighting corresponding to the state of individual LCD rows to reduce or avoid visual artifacts, improve efficiency, and reduce cost. Summary of the invention

[0012] This summary is provided to introduce some concepts in a simplified form that are further described in the detailed description below. It is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.

[0013] In one embodiment, the LED panel has an array of lighting units arranged in a plurality of LED rows and a plurality of LED channels, each lighting unit being a single LED pixel or a plurality of LED pixels connected in series. The plurality of LED rows are connected to two or more drivers through a plurality of scanning switches, and the plurality of LED channels are connected to a plurality of current sinks or current sources. In addition, the two or more drivers are connected to the plurality of LED rows in an interleaved manner, wherein two adjacent LED rows between the plurality of LED rows are respectively connected to two of the two or more drivers.

[0014] In another embodiment, the LED panel can be operated by using two or more drivers to sequentially drive multiple LED rows, wherein one LED row is driven by one driver at a time, two adjacent LED rows are driven by two drivers respectively, and the start times of the driving signals are different.

[0015] In another embodiment, the LCD display comprises an LCD panel and an LED panel providing backlight for the LCD panel. The LED panel comprises one or more LED regions. The LCD panel comprises one or more LCD regions. Each of the one or more LCD regions is configured with an LED region to provide backlight illumination therefor. Each LED region comprises an array of lighting units arranged in a plurality of LED rows and a plurality of LED channels, and each lighting unit is a single LED pixel or a plurality of LED pixels connected in series.

[0016] A plurality of LED rows in each LED region are connected to two or more drivers through a plurality of scan switches, and a plurality of LED channels are connected to a plurality of current sinks or current sources.

[0017] In other embodiments, the LCD panel in the LCD display may have a screen size in the range of "5 to 100". It may have 1 to 7 LED zones. Each LED zone has 18 to 160 LED rows.

[0018] In other embodiments, there may be 2 to 24 drivers connected to multiple LED rows in each LED region of the LED panel.

[0019] A method for providing backlighting for an LCD display using an LED panel may include the steps of turning on the LCD display by turning on a first LCD pixel in a first LCD area in the LCD panel; turning on a first LED row in a first LED area in the LED panel that provides backlighting for the first LCD area; and sequentially driving a plurality of LED rows in the first LED area within a delay time. "Turning on" means providing a drive unit, such as a PWM pulse, to the LED pixels in the LED row. The rising edge of the PWM pulse is the start time of the "turning on" action. The delay time is the time difference between the start times of two adjacent, sequentially driven LED rows.

[0020] In some embodiments, the delay time is equal to or greater than a frame time when the LCD display is operating divided by the total number of LCD rows in the LCD panel.

[0021] In a further embodiment, when the LCD panel has more than one LCD region and the LED panel has more than one LED region, all of the more than one LED regions will be driven sequentially, and a delay time will be globally implemented for all LED regions, that is, between any two adjacent sequentially driven LED rows in the more than one LED regions.

[0022] In another embodiment of the present invention, the PWM pulse length (T pwm ) method comprises the following steps: determining a hold-limit pulse length (Hold-Limit T pwm ), frame limit pulse length (Frame-Limit T pwm ) and Delay-Limit T pwm );Determine T pwm Less than or equal to Hold-Limit T pwm , Frame-Limit T pwm and Delay-Limit T pwm A minimum value in ; and configuration to achieve T pwm LED driver.

[0023] Hold-Limit T pwm The LCD panel is limited by the retention time of the LCD pixels, which refers to the period of time during which the LCD pixels remain stable. pwm Limited by the frame time of the LCD display. pwm Limited by the number of LED zones in the LED panel. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The teachings of the present invention can be readily understood by considering the following detailed description in conjunction with the accompanying drawings.

[0025] Figure 1 An array of LED groups in a portion of an LED panel is shown.

[0026] Figure 2 yes Figure 1 A simplified circuit diagram of the LED panel section.

[0027] Figure 3 yes Figure 1 and 2 Timing diagram of the LED panel part.

[0028] Figure 4 The voltage response of the LCD area and its relationship to the corresponding backlight LED area is shown.

[0029] Figure 5 The voltage responses of five different LCD regions in an LCD display panel are shown. DETAILED DESCRIPTION

[0030] Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings. It is noted that, wherever practicable, like or similar reference numerals may be used among the drawings and may represent like or similar elements.

[0031] The accompanying drawings depict embodiments of the invention for purposes of illustration only. Those skilled in the art will readily appreciate from the following description that there are alternative embodiments without departing from the general principles of the invention.

[0032] The embodiments of the present invention take a 4K LCD panel and its LED backlight panel as an example. However, the topology of the LED panel, the method of driving the LED panel, and the method of determining the design variables and determining the operating parameters are not limited to LCD displays or LED backlight panels.

[0033] In the present invention, a driver core refers to a driver circuit that drives an LED, which may include components such as a scan switch, one or more current receivers, or one or more current sources. The scan switch may be a PMOS or an NMOS, and the current drive circuit may be a current receiver or a current source. The driver core may reside on a driver chip. Alternatively, a driver chip may include one or more driver cores. For example, a driver chip may include a driver core so that it can handle high power loads, such as in large LED panels. If the power load is not high, such as in small LED panels for handheld devices, the driver chip may include several driver cores. In the present invention, "driver" and "driver core" are used interchangeably unless otherwise specified.

[0034] In one embodiment, when all LED groups in the same LED row are turned on simultaneously, a common delay time (T comm ). The delay time is the minimum time difference between the rising edge of the PWM pulse driving the LED row and the rising edge of the PWM pulse driving the adjacent LED row. Common delay time T comm is the delay time globally applied to all LED rows in the LED panel. T comm may be greater than or equal to the time required to update all LCD pixels in the LCD panel. In the above example of a 4k LCD panel running at a frame rate of 120 Hz, T comm is set to a value greater than or equal to 92.5 μs. In the present invention, 92.5 μs is the default common delay time T in the embodiment. comm , it should be understood that T comm Can have different values.

[0035] In another embodiment of the present invention, the LED row is lit after its corresponding LCD row is stable to illustrate the response time (T response ) and common delay time (T comm ).

[0036] According to one embodiment of the present invention, a single LED driver core drives multiple rows of LEDs in a scanning topology. In addition, multiple LED driver cores are interleaved. "Interleaved," "interleaved," or "interleaved" means that the rows of LEDs driven by different drivers are interleaved together rather than separated into different blocks. For example, the first row of LEDs is driven by a first driver, the second row of LEDs is driven by a second driver, and the third row of LEDs is driven by a third driver, and this pattern is repeated across the entire LED panel. For example, in an LED array with 9 rows of LEDs, the first driver drives rows 1, 4, and 7, the second driver drives rows 2, 5, and 8, and the third driver drives rows 3, 6, and 9, so the LED array has 9 interleaved rows of LEDs driven by 3 interleaved drivers. Note that the first driver core, the second driver core, and the third driver core can reside on one driver chip or on three separate driver chips.

[0037] Figure 1This is a schematic diagram of a section of an LED panel that has 16 channels, 18 rows of LED groups - a total of 288 LED groups, 4 LED pixels in series. This section is called a 16 (channel) × 6 (scan) × 3 (interleaved) section because the LED groups are linked in 16 channels, connected to one of three interleaved drivers through 6 scan switches, and have a repeating pattern of 3 interleaved LED rows. The entire LED panel for a 4K LCD panel has 160 × 90 LED groups, so it can contain 50 Figure 1 The sections shown are, for example, arranged in a 10 x 5 array of LED sections.

[0038] exist Figure 1 In the section, 6 rows of LED groups CX0 <0> To CX0 <5> By the first driver (driver <0> ) driver, 6-row LED group CX1 <0> To CX1 <5> By the second driver (driver <1> ) driver, 6-row LED group CX2 <0> To CX2 <5> By the third driver (driver <2> ) driver. For simplicity, Figure 1 The drive is not shown.

[0039] Figure 2 right Figure 1 The LED panel section shown gives another description. It shows that each LED group is connected to 16 current sinks I sink <0-15> one of them, and driven by one of the driver cores driver<0-2>. Figure 1 and Figure 2 , connect CX0 <0> To CX0 <5> The first LED channel in each row is connected to the I sink0 <0> And by the drive <0> Drive; connect CX0 <0> To CX0 <5> The second LED channel in each row is connected to the I sink0 <1> And by the drive <0> Drive; and connect CX0 <0> To CX0 <5> The channel of the last LED group in each row (i.e., the 16th LED group) is connected to I sink0 <15> And by the drive <0> Similarly, connect CX1 <0> To CX1 <5> The first LED channel in each row is connected to the I sink1 <0> And by the drive <1> Drive; connect CX1 <0> To CX1 <5> The second LED channel in each row is connected to the I sink1 <1> And by the drive <1> Drive; and connect CX1 <0> To CX1 <5> The channel of the last LED group (i.e., the 16th LED group) is connected to I sink1<15> And by the drive <1> In addition, connect CX2 <0> To CX2 <5> The first LED channel in each row is connected to the I sink2 <0> And by the drive <2> Drive; connect CX2 <0> To CX2 <5> The second LED channel in each row is connected to the I sink2 <1> And by the drive <2> Drive; and connect CX2 <0> To CX2 <5> The channel of the last LED group in each row (i.e., the 16th LED group) is connected to I sink2 <15> And by the drive <2> In this way, all three driver cores <1-3> use the same 16 current sinks I sink <0-15>.

[0040] Compared to the traditional topology where one driver drives six adjacent rows, Figure 1 and Figure 2 The interleaved topology of LED rows in the middle can drive larger LED arrays. In the traditional topology, one driver drives 6 adjacent rows. Because, instead of driving a 6-row block in one scan time, the interleaved topology can drive an 18-row block area of ​​LEDs in about the same time.

[0041] There are certain limitations to the interleaved topology described above. For example, IR drop prevents the driver cores from driving large areas of LCD displays (e.g., over 20 inches) in an interleaved topology. Therefore, factors such as the physical size of the LCD panel and the distance between the driver cores limit the range of the number of interleaved drivers. For example, for a cell phone or laptop, since the LED driver cores are arranged in a small area, all the driver cores can be interleaved with each other. On the other hand, for an LED backlight panel in an LCD TV, the distance between the driver cores at one end of the panel and the driver cores at the other end of the panel can be far apart so that they control the same area of ​​LEDs.

[0042] Take the LED backlight panel of a 4K LCD panel as an example. It contains an array of 50 16×6×3 sections, such as Figure 1 and 2 As shown, each section has 3 staggered driver cores. Therefore, there are a total of 150 driver cores distributed across the LED backlight panel, arranged in rows and columns. As long as the negative impact is negligible, for example, the infrared voltage drop (IRdrop) is small enough, multiple LED driver cores can be staggered to drive the LEDs in a given area of ​​the LED panel.

[0043] In the present invention, one LED block is referred to as a zone, where several driver cores drive the LEDs in an interleaved manner. The LED backlight panel of a large LCD panel can be divided into multiple zones. Figure 1 and 2 As shown, a portion of an LED panel can be such an area. Each area has a certain size, for example, less than 20 cm. The area can be larger or smaller than Figure 1 and 2 For example, a zone can have 2 or more interleaved drivers, each driving 6 rows of LED groups, instead of 3 interleaved drivers, each driving 6 rows of LED groups. In addition, a zone can have a greater or lesser number of channels, such as Figure 1 and 2 shown.

[0044] Figure 3 is an exemplary timing diagram for LED backlight areas. pwm is the time that the LED group is lit for each frame. After the LCD display is stable, apply the same T to all LED rows in turn. pwm Two adjacent PWM pulses drive two adjacent LED rows respectively, and the delay time between the rising edges of two adjacent PWM pulses is 92.5μs. The delay time between the start time of the last row of LEDs in the current scan and the start time of the first row of LEDs in the next scan is called "scan delay" in the present invention, and this delay time should be greater than or equal to T comm The actual scan delay time between scans depends on T pwm When T pwm >n×T comm , n is the number of cores of the interleaved driver ( Figure 1 and 2 n=3), the scanning delay time between two LED rows is equal to T pwm -(n-1)×T comm When T pwm =n×T comm When the scanning delay time is T comm .

[0045] The entire LED backlight panel of a 4K LCD panel can be divided into 5 zones, and the delay between adjacent zones ("zone delay") is equal to the total number of LED rows in each zone and T comm A 4K LCD panel can similarly be divided into 5 LCD zones, each of which is backlit by a corresponding LED zone.

[0046] Figure 4 The voltage response of the LCD area and its relationship to the corresponding backlight LED area with 18 rows of LEDs is shown. LCD Settling Time Figure 4 Indicates the first LCD group stabilization time period. Figure 5The delay in five regions from the first LCD pixel in the first row to the last LCD pixel in the last row is shown. The LCD region delay time is the sum of all delays in updating the LCD pixels in the same region. The LEDs are then clocked to compensate for this delay.

[0047] like Figure 4 As shown, the interleaved topology enables significant overlap between three consecutive PWM pulses, thereby increasing light output. It also enhances local dimming control because the PWM increment step size is relatively large compared to the standard scan topology, assuming that the LED groups are driven at the same maximum current and the same maximum clock speed allowed in the LED driver. In other words, reducing motion blur is more difficult in an LED panel with a standard scan topology that reduces motion blur because it cannot produce a high enough light output (i.e., not bright enough) and its local dimming adjustment does not have sufficient bit depth.

[0048] Another significant advantage is that the interleaved scan topology has less power fluctuations. When switching from one scan to another, the standard scan topology turns channels on and off, so the power supply will experience high-frequency output current fluctuations. Current fluctuations increase electromagnetic interference (EMI) and shorten the life of the power supply. With the interleaved scan topology, multiple rows of LEDs are turned on at the same time most of the time, so the drive current is drawn continuously from the power supply, which greatly reduces the number of high-frequency current spikes experienced by the power supply.

[0049] Table 1 shows the relationship between the parameters of 4K LCD panels of different sizes backlit by corresponding LED backlight panels. Assuming the frame rate is 120Hz, the response time is 7ms, T hold It is 1333.33μs.

[0050] Table 1

[0051]

[0052]

[0053]

[0054] In Table 1, "Zone Number" is the number of zones the LED panel is divided into, which is a design choice limited by factors such as IR drop. "Zone Delay" is the total delay time in a zone, which is equal to 1 / (Number of Zones * Frame Rate). "Total Number of Rows" is the total number of rows of LED groups in the entire LED panel, which is a design choice. "Number of Scans" refers to the number of scans, that is, the number of scan lines connected to each driver. Figure 1 and 2In the example above, the number of scans is 6, or S = 6. "Number of rows per zone" refers to the number of rows of LEDs in each zone. N is the number of interleaved LED drivers in each zone minus 1. "Pitch" is the size of the pitch between the LED pixels, which is a design choice. "T comm ” is the common delay of the entire LED panel and is equal to 1 / (frame rate × total number of rows).

[0055] T pwm The higher the maximum value, the brighter the LED panel will be, which has the advantage of providing a higher dynamic range. However, in addition to material and labor costs, T pwm There are also some other restrictions.

[0056] First, T pwm Add T comm Cannot be longer than T hold , so T pwm The maximum value cannot exceed (T hold -T comm ), that is, “Hold-Limit T pwm "It is easy to understand that T comm Must be less than T hold , otherwise T pwm becomes negative.

[0057] Secondly, T pwm Also affected by T frame >=S×T pwm +N×T comm The frame time limit in . The T calculated according to this limit pwm In Table 1, it is specified as “Frame-Limit T pwm ”.

[0058] In addition, according to the equation T hold +T delay >=S×T pwm +(N+2)×T comm , T pwm Can be limited by regional delay (T delay ) in the delay length. The T obtained in this way pwm is designated as the "delay limit T pwm ”.

[0059] In the “Hold-Limit T pwm ”, “Frame-Limit T pwm ” and “Delay-Limit T pwm "Design T pwm " is the lowest value. This is the LED driver assigned the highest T in the corresponding LED panel configuration pwmThe LED driver can be designed according to its value. By properly designing and configuring the PWM generator, the common delay in LED driving can be achieved.

[0060] Using this set of design parameters and constraints, Table 1 outputs the design T pwm -Theoretical maximum amount of time the LEDs are on per frame. Several observations can be made. First, larger LCD panels require multiple zones in their backlight LED panels, while smaller LCD panels only require a single zone. The turning point is between the 15.6" LCD panel size and the 14" LCD panel size. Note that all zones are driven with interleaved drivers.

[0061] Secondly, for larger LED panels, design T pwm Affected by Delay-Limit T pwm According to the limitation of T hold +T delay >=S×T pwm +(N+2)×T comm ,Delay-Limit T pwm is the area delay (T delay ) in the delay length. For smaller LED panels, design T pwm Subject to Hold-Limit T pwm Limit, equal to T hold -T comm The turning point again occurs between the 15.6-inch LCD panel size and the 14-inch LCD panel size.

[0062] The design T in Table 1 pwm It is neither the only solution nor the best one. Much depends on design parameters such as the number of interleavings, the number of scans, and the pitch size. Table 1 shows the estimated maximum T given several design parameters. pwm An exemplary method of

[0063] In summary, implementing common delay in the scan drive of LED backlight panels has several advantages over traditional LED backlighting methods. Implementing common delay time between consecutive LED rows reduces blur in the scan backlight. It takes advantage of slow response time and common delay to enable LED pixels to obtain longer T pwm , giving the LED a better contrast. The interleaved topology of the LED panel takes advantage of the slow response time and long update delay of the LCD, saving power, improving output performance, and reducing material costs by sharing resources between driver cores. This in turn ensures that the number of LED drivers during this period can be effectively powered to the LEDs, thereby reducing total power consumption and current fluctuations.

[0064] Although the embodiments of the present invention have been shown and described, those skilled in the art may make modifications without departing from the spirit or teachings of the present invention. The embodiments described herein are merely exemplary and not restrictive. Many changes and modifications may be made to the methods, systems and devices within the scope of the present invention.

[0065] For example, an LED panel with an interleaved topology can be used as a standalone device rather than as a backlight panel for an LCD panel in a liquid crystal display. Such an LED panel can be driven according to the specific application in which it is used and does not necessarily need to implement a common delay time. In addition, the delay times of different areas or rows of the LED panel can be differentiated so that specific applications can be better served.

[0066] Therefore, the scope of protection is not limited to the embodiments described herein. The scope of protection is limited only by the claims. The scope of the claims shall include all equivalents of the subject matter of the claims.

Claims

1. A method for selecting PWM pulse length to drive an LED panel in an LCD display, characterized in that: include: Determine Hold-Limit T pwm , Frame-Limit T pwm and Delay-Limit T pwm , where Hold-Limit T pwm Indicates the limit pulse length, Frame-Limit T pwm Indicates the frame limit pulse length, Delay-Limit T pwm Indicates delay limit pulse length; Determine T pwm Less than or equal to Hold-Limit T pwm , Frame-Limit T pwm and Delay-Limit T pwm The lowest value among them, T pwm Indicates the time the LED group is lit per frame; and Configure an implementation T pwm LED driver, Hold-Limit T pwm Limited by the hold time of the LCD pixels in the LCD panel, where the hold time is the period of time during which the LCD pixels remain stable, Frame-Limit T pwm Limited by the frame time of the LCD display, And the Delay-Limit T pwm Limited by the number of LED zones in the LED panel; T pwm +T comm <=T hold , T calculated according to this constraint pwm Hold-Limit T pwm ; T frame >=S×T pwm +N×T comm , T calculated according to this constraint pwm Frame-Limit T pwm ; T hold +T delay >=S×T pwm +(N+2)×T comm , T calculated according to this constraint pwm Delay-LimitT pwm ; T comm Indicates the common delay time of the LED panel, T frame Indicates the frame time of the LCD display, T hold Indicates the retention time of the LCD display, T delay It represents the regional delay time of the LCD display, S represents the number of scan lines connected to each driver, and N represents the number of interleaved LED drivers in each area minus 1; The LCD display comprises an LCD panel and an LED panel for providing backlight illumination for the LCD panel, wherein the LED panel comprises one or more LED areas, the LCD panel comprises one or more LCD areas, each LED area is configured to provide backlight illumination for one of the one or more LCD areas, wherein each LCD area comprises an LCD pixel array, wherein each LED area comprises an array of lighting units arranged in a plurality of LED rows and a plurality of LED channels, each lighting unit is a single LED pixel or a plurality of LED pixels connected in series, wherein a plurality of LED rows in each LED area are connected to two or more drivers via a plurality of scanning switches, and a plurality of LED channels are connected to a plurality of current sinks or current sources, and wherein two or more drivers are connected to a plurality of LED rows in an interlaced manner, wherein two adjacent LED rows among the plurality of LED rows are respectively connected to two drivers among the two or more drivers.

2. The method according to claim 1, characterized in that The screen size of the LCD panel ranges from 5 inches to 100 inches.

3. The method according to claim 1, characterized in that The number of LED zones ranges from 1 to 7.

4. The method according to claim 1, characterized in that Each LED zone has 18 to 160 LED rows.

5. The method according to claim 1, characterized in that The multiple LED rows in each LED zone are connected to 2 to 24 drivers.

6. The method according to claim 1, characterized in that The lighting unit is a group of four LED pixels connected in series.

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