Backlight module and display device

Abstract

The present application belongs to the field of display, and specifically relates to a backlight module and a display device. The backlight module includes at least N backlight sub-zones, each of which is provided with a light-emitting unit. The backlight module also includes a first control circuit and a second control circuit. The first light-emitting unit is directly connected to a first power source, and the second light-emitting unit is indirectly connected to the first power source via the first control circuit. Each second light-emitting unit is connected to the second power source via a first power line. At least one first light-emitting unit is connected to X first power lines via the second control circuit. The first control circuit and the second control circuit are also connected to a control unit. The sum of the off-duty cycles of the second light-emitting units connected to the X first power lines is equal to the on-duty cycle of the first light-emitting units connected to the X first power lines. This improves the problem of unstable boost operation of the driver chip and increased electromagnetic interference caused by load fluctuations on the X first power lines.

Description

Technical Field

[0001] The present application belongs to the field of display, and specifically relates to a backlight module and a display device. Background Art

[0002] Liquid crystal display (LCD) panels have a wide viewing angle. However, while people enjoy the visual experience brought by the wide viewing angle, they sometimes also hope that the viewing angle of the display panel can be adjusted to a smaller value, so as to effectively protect business secrets or personal privacy and avoid business losses or embarrassment caused by leakage of screen information.

[0003] In order to achieve the viewing angle adjustment (anti-peeping) function, the backlight module of some display devices is provided with multiple backlight partitions, and the brightness of the backlight partitions gradually decreases from the middle area to the two side areas. The display device cannot be clearly displayed when viewed from both sides, thus achieving anti-peeping on both sides.

[0004] In existing backlight modules, the driver chip outputs PWM (pulse width modulation) signals with varying duty cycles to the light strings in different backlight zones, adjusting the brightness of each zone, gradually decreasing from the center to the sides. However, these PWM signals, when outputted by the driver chip, cause the driver chip's load to vary periodically, leading to unstable boost operation and increased electromagnetic interference. Summary of the Invention

[0005] The purpose of the present application is to provide a backlight module and a display device to improve or eliminate the problem of unstable boosting operation of the driver chip and enhanced electromagnetic interference caused by periodic changes in the load of the driver chip.

[0006] To achieve the above-mentioned object, the present application provides a backlight module, comprising at least N backlight partitions, wherein the N backlight partitions are arranged sequentially along a first direction, where N is greater than or equal to 3, and each backlight partition is provided with a light-emitting unit. The backlight module further comprises:

[0007] a first control circuit, wherein the N light-emitting units are divided into a first light-emitting unit and a second light-emitting unit, the first light-emitting unit is directly connected to a first power source, and the second light-emitting unit is indirectly connected to the first power source via the first control circuit;

[0008] a second control circuit, wherein each of the second light-emitting units is connected to a second power source via a first power line, and at least one of the first light-emitting units is connected to X first power lines via the second control circuit, where X is greater than or equal to 2; the first control circuit and the second control circuit are further connected to a control unit, and the control unit is capable of outputting a pulse width modulation signal in a narrow viewing angle mode, and controlling the on-duty cycle or off-duty cycle of at least some of the light-emitting units by controlling the on-duty cycle or off-duty cycle of at least some of the light-emitting units so that the brightness of the N backlight subareas gradually increases or decreases along the first direction by controlling the on-duty cycle or off-duty cycle of the light-emitting units and the first power source and the second power source;

[0009] The sum of the off-duty cycles of the second light-emitting units connected to the X first power lines is equal to the on-duty cycles of the first light-emitting units connected to the X first power lines.

[0010] Optionally, the Nth light-emitting unit along the first direction is the first light-emitting unit, the Nth light-emitting unit is directly connected to the first power supply and to the second power supply through a second power line, and the turn-on duty cycle of the Nth light-emitting unit is 100%.

[0011] Optionally, each of the first light-emitting units except the Nth light-emitting unit is connected to X first power lines through the second control circuit, and the number of first power lines connected to each first light-emitting unit is the same or different. In the narrow viewing angle mode, the load on each first power line is equal.

[0012] Optionally, N is equal to 8, the turn-on duty cycle of the first light-emitting unit is 50%, the turn-on duty cycle of the second light-emitting unit is 55%, the turn-on duty cycle of the third light-emitting unit is 60%, the turn-on duty cycle of the fourth light-emitting unit is 70%, the turn-on duty cycle of the fifth light-emitting unit is 80%, the turn-on duty cycle of the sixth light-emitting unit is 90%, the turn-on duty cycle of the seventh light-emitting unit is 95%, and the turn-on duty cycle of the eighth light-emitting unit is 100%.

[0013] Optionally, the first control circuit includes five first transistors, the first ends of the five first transistors are all connected to the first power supply, the second end of the first first transistor is connected to the fifth light-emitting unit, the second end of the second first transistor is connected to the fourth light-emitting unit, the second end of the third first transistor is connected to the third light-emitting unit, the second end of the fourth first transistor is connected to the second light-emitting unit, the second end of the fifth first transistor is connected to the first light-emitting unit, and the control ends of the five first transistors are respectively connected to the control unit;

[0014] The second control circuit includes five second transistors, the first end of the first second transistor, the first end of the second second transistor, and the first end of the fourth second transistor are all connected to the seventh light-emitting unit, the second end of the first second transistor is connected to the fifth light-emitting unit, the second end of the second second transistor is connected to the fourth light-emitting unit, the second end of the fourth second transistor is connected to the second light-emitting unit, the first end of the third second transistor and the first end of the fifth second transistor are both connected to the sixth light-emitting unit, the second end of the third second transistor is connected to the third light-emitting unit, and the second end of the fifth second transistor is connected to the first light-emitting unit. The control ends of the five second transistors are respectively connected to the control unit.

[0015] Optionally, the first transistor is a P-type transistor, and the second transistor is an N-type transistor.

[0016] Optionally, the backlight module also includes a third control circuit, which includes at least one third transistor. Each of the first light-emitting units except the Nth light-emitting unit is connected to the first end of each third transistor, and the second end of each third transistor is connected to the second power supply through a second power line, and the control end of each third transistor is connected to the control unit.

[0017] Optionally, the backlight module includes 2N backlight partitions. In the first direction, the first N backlight partitions and the last N backlight partitions are symmetrically arranged. The control unit can output a pulse width modulation signal in a narrow viewing angle mode, so that the brightness of the 2N backlight partitions gradually increases and then gradually decreases along the first direction.

[0018] Optionally, the light-emitting units of the symmetrically arranged backlight partitions are connected in series with the boundary line between the Nth backlight partition and the N+1th backlight partition as the symmetry center.

[0019] The present application also provides a display device, comprising:

[0020] The backlight module;

[0021] A control unit is connected to the first control circuit and the second control circuit, and the control unit includes a timing controller.

[0022] The backlight module and display device disclosed in this application have the following beneficial effects:

[0023] In the present application, a backlight module includes at least N backlight sub-zones, each of which is provided with a light-emitting unit. The backlight module also includes a first control circuit and a second control circuit. The first light-emitting unit is directly connected to a first power source, and the second light-emitting unit is indirectly connected to the first power source via the first control circuit. Each second light-emitting unit is connected to the second power source via a first power line, and at least one first light-emitting unit is connected to X first power lines via the second control circuit. The first and second control circuits are also connected to a control unit. The control unit is capable of outputting a pulse-width modulation signal in a narrow viewing angle mode to gradually increase or decrease the brightness of the N backlight sub-zones along a first direction. Because the sum of the off-duty cycles of the second light-emitting units connected to the X first power lines is equal to the on-duty cycle of the first light-emitting units connected to the X first power lines, some of the first light-emitting units and some of the second light-emitting units can share the same first power line, thereby improving or eliminating the problem of unstable boost operation of the driver chip and increased electromagnetic interference caused by load fluctuations on the X first power lines.

[0024] Other features and advantages of the present application will become apparent from the following detailed description, or may be learned in part by practice of the present application.

[0025] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The accompanying drawings are incorporated into and constitute a part of the specification, illustrate embodiments consistent with the present application, and together with the specification, are used to explain the principles of the present application. Obviously, the drawings described below are only some embodiments of the present application, and those skilled in the art can derive other drawings based on these drawings without inventive effort.

[0027] Figure 1 This is a connection diagram of the backlight module and the control unit in Example 1 of the present application.

[0028] Figure 2 This is a schematic diagram of backlight partitioning of the backlight module in Example 1 of the present application.

[0029] Figure 3 It is a structural diagram of the backlight module in Example 1 of the present application.

[0030] Figure 4 Schematic diagram of the turn-on duty cycle of each light-emitting unit in the first embodiment of the present application.

[0031] Figure 5 1 is a timing diagram of the duty cycle of the light-emitting unit in the first embodiment of the present application.

[0032] Figure 6This is a load diagram of the first power line and the second power line in Example 1 of the present application.

[0033] Figure 7 This is a schematic diagram of a backlight module with a third control circuit in the first embodiment of the present application.

[0034] Figure 8 It is a structural diagram of the display device in Example 2 of the present application.

[0035] Description of reference numerals:

[0036] 100. Backlight module; 101. Backlight partition;

[0037] 110, light-emitting unit; 110a, first light-emitting unit; 110b, second light-emitting unit; 111, first light-emitting unit; 112, second light-emitting unit; 113, third light-emitting unit; 114, fourth light-emitting unit; 115, fifth light-emitting unit; 116, sixth light-emitting unit; 117, seventh light-emitting unit; 118, eighth light-emitting unit;

[0038] 120, a first control circuit; 121, a first first transistor; 122, a second first transistor; 123, a third first transistor; 124, a fourth first transistor; 125, a fifth first transistor;

[0039] 130, second control circuit; 131, first second transistor; 132, second second transistor; 133, third second transistor; 134, fourth second transistor; 135, fifth second transistor;

[0040] 140a, a first power line; 140b, a second power line; 151, a third transistor;

[0041] 200, driving chip; 210, first power supply; 300, control unit. DETAILED DESCRIPTION

[0042] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided so that this application will be thorough and complete and will fully convey the concepts of the example embodiments to those skilled in the art.

[0043] In addition, described feature, structure or characteristic can be combined in one or more embodiments in any suitable manner.In the following description, many specific details are provided so as to provide a full understanding of the embodiments of the present application. However, it will be appreciated by those skilled in the art that the technical scheme of the present application can be put into practice without one or more of the specific details, or other methods, components, devices, steps etc. can be adopted. In other cases, known methods, devices, implementations or operations are not shown or described in detail to avoid blurring the various aspects of the application.

[0044] The present application is further described below in conjunction with the accompanying drawings and specific embodiments. It should be noted that the technical features involved in the various embodiments of the present application described below can be combined with each other as long as they do not conflict with each other. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, and should not be understood as limiting the present application.

[0045] Example 1

[0046] See also Figure 1 and Figure 2 As shown, in this embodiment, the backlight module 100 includes at least N backlight sub-areas 101, which are arranged in sequence along a first direction, where N is greater than or equal to 3. Each backlight sub-area 101 is provided with a light-emitting unit 110. The light-emitting unit 110 includes at least one light-emitting diode (LED). When the light-emitting unit 110 includes multiple LEDs, the multiple LEDs are connected in series. In the backlight sub-areas 101, the multiple LEDs can be arranged in sequence along a second direction, which is perpendicular to the first direction, or the multiple LEDs can be arranged in an array along the first direction and the second direction.

[0047] The backlight module 100 also includes a first control circuit 120 and a second control circuit 130. The N light-emitting units 110 can be divided into a first light-emitting unit 110a and a second light-emitting unit 110b. The first light-emitting unit 110a is directly connected to the first power supply 210, and the second light-emitting unit 110b is indirectly connected to the first power supply 210 through the first control circuit 120. Each second light-emitting unit 110b is connected to the second power supply through a first power line 140a. At least one first light-emitting unit 110a is connected to X first power lines 140a through the second control circuit 130, where X is greater than or equal to 2. When the backlight module 100 includes multiple first light-emitting units 110a, other first light-emitting units 110a can be connected to the second power supply through a second power line 140b. In other words, at least some of the first power lines 140a serve as common power lines connecting the first light-emitting unit 110a and the second light-emitting unit 110b to the second power supply.

[0048] The first control circuit 120 and the second control circuit 130 are also connected to the control unit 300. The control unit 300 can output a pulse width modulation signal in the narrow viewing angle mode. By controlling the conduction or disconnection of the light-emitting unit 110 and the first power supply 210 and the second power supply, the on duty cycle or off duty cycle of at least part of the light-emitting unit 110 is controlled, so that the brightness of the N backlight partitions 101 gradually increases or decreases along the first direction to achieve an anti-peeping function.

[0049] The sum of the off-duty cycles of the second light-emitting units 110b connected to the X first power lines 140a is equal to the on-duty cycle of the first light-emitting units 110a connected to the X first power lines 140a. For example, along the first direction, the seventh light-emitting unit 117 is connected to the first power lines 140a of the fifth light-emitting unit 115, the fourth light-emitting unit 114, and the second light-emitting unit 112 via the second control circuit 130. The seventh light-emitting unit 117 is the first light-emitting unit 110a, and the on-duty cycle of the seventh light-emitting unit 117 is 95%. The fifth light-emitting unit 115, the fourth light-emitting unit 114, and the second light-emitting unit 112 are the second light-emitting units 110b. The off-duty cycle of the fifth light-emitting unit 115 is 20%, the off-duty cycle of the fourth light-emitting unit 114 is 30%, and the off-duty cycle of the second light-emitting unit 112 is 45%.

[0050] The backlight module's driver chip outputs pulse-width modulation signals with varying duty cycles to the light strings in different backlight zones, adjusting the brightness of each zone, gradually decreasing from the center to the sides. However, the driver chip's output of pulse-width modulation signals with varying duty cycles causes the driver chip's load to vary periodically, leading to unstable boost operation and increased electromagnetic interference.

[0051] In this embodiment, the backlight module 100 includes at least N backlight partitions 101, each backlight partition 101 is provided with a light-emitting unit 110, and the backlight module 100 also includes a first control circuit 120 and a second control circuit 130. The first light-emitting unit 110a is directly connected to the first power supply 210, and the second light-emitting unit 110b is indirectly connected to the first power supply 210 through the first control circuit 120. Each second light-emitting unit 110b is connected to the second power supply through a first power line 140a, and at least one first light-emitting unit 110a is connected to X first power lines 140a through the second control circuit 130. The first control circuit 120 and the second control circuit 130 are also connected to the control unit 300. The control unit 300 can output a pulse width modulation signal in a narrow viewing angle mode, so that the brightness of the N backlight partitions 101 gradually increases or decreases along the first direction to achieve an anti-peek function. Since the sum of the off-duty cycles of the second light-emitting units 110b connected to the X first power lines 140a is equal to the on-duty cycle of the first light-emitting units 110a connected to the X first power lines 140a, some of the first light-emitting units 110a can be turned on during the off period of the second light-emitting units 110b. That is, some of the first light-emitting units 110a and some of the second light-emitting units 110b can share the first power line 140a, thereby improving or eliminating the problem of unstable boost operation of the driver chip and enhanced electromagnetic interference caused by load fluctuations on the X first power lines 140a.

[0052] In some embodiments, the Nth light-emitting unit 110 along the first direction is the first light-emitting unit 110a. The Nth light-emitting unit 110 is directly connected to the first power source 210 and is connected to the second power source via a second power line 140b. The on-duty cycle of the Nth light-emitting unit 110 is 100%. For example, if N is 8, the eighth light-emitting unit 110 is directly connected to the first power source 210 and is connected to the second power source via a second power line 140b.

[0053] It should be noted that the backlight module 100 may further include an N+1th backlight subarea 101 and an N+2th backlight subarea 101, and the duty cycle of the light-emitting units 110 of the backlight subarea 101 on the side of the Nth backlight subarea 101 away from the N-1th backlight subarea 101 is 100%. In other words, the brightness of one side of the backlight module 100 gradually decreases.

[0054] In narrow viewing angle mode, the brightness of one side of the backlight module 100 gradually decreases, and the backlight module 100 and the display device can achieve single-side privacy protection. A single-side privacy protection display device can be used in the passenger seat of a car to prevent peeping from the driver's side, thereby preventing the display content from disturbing the driver and affecting driving safety.

[0055] In some embodiments, each first light-emitting unit 110a except the Nth light-emitting unit 110 is connected to X first power lines 140a via the second control circuit 130. The number of first power lines 140a connected to each first light-emitting unit 110a may be the same or different. In the narrow viewing angle mode, the load on each first power line 140a is equal, and the load on the first power line 140a is also equal to the load on the second power line 140b.

[0056] In narrow viewing angle mode, the load on each first power line 140a is equal, and the load on the first power line 140a is also equal to the load on the second power line 140b. This eliminates load fluctuations on the first power line 140a, solving the problem of unstable boost operation of the driver chip and increased electromagnetic interference. In addition, the filter capacitor used to reduce electromagnetic interference is only effective for a single waveform and cannot respond to multiple waveforms, making electromagnetic interference difficult to resolve. The load on each first power line 140a is equal, and the load on the first power line 140a is also equal to the load on the second power line 140b. This eliminates load fluctuations on the first power line 140a. The filter capacitor only needs to respond to a single waveform, which is conducive to solving electromagnetic interference problems.

[0057] In some embodiments, N is equal to 8, the on-duty cycle of the first light-emitting unit 111 is 50%, the on-duty cycle of the second light-emitting unit 112 is 55%, the on-duty cycle of the third light-emitting unit 113 is 60%, the on-duty cycle of the fourth light-emitting unit 114 is 70%, the on-duty cycle of the fifth light-emitting unit 115 is 80%, the on-duty cycle of the sixth light-emitting unit 116 is 90%, the on-duty cycle of the seventh light-emitting unit 117 is 95%, and the on-duty cycle of the eighth light-emitting unit 118 is 100%.

[0058] The first to fifth light-emitting units 111 to 115 constitute the second light-emitting unit 110 b, and the sixth to eighth light-emitting units 116 to 118 constitute the first light-emitting unit 110 a. The on-duty cycle of the seventh light-emitting unit 117 is equal to the sum of the off-duty cycles of the fifth light-emitting unit 115, the fourth light-emitting unit 114, and the second light-emitting unit 112. The on-duty cycle of the sixth light-emitting unit 116 is equal to the sum of the off-duty cycles of the third light-emitting unit 113 and the first light-emitting unit 111.

[0059] By setting the on-duty cycle of each light-emitting unit 110 in the narrow viewing angle mode, the brightness of the first light-emitting unit 111 to the eighth light-emitting unit 118 can be gradually increased to achieve an anti-peeping function. This also ensures that each first light-emitting unit 110a can be turned on during the off period of the X second light-emitting units 110b. This allows the first light-emitting unit 110a and the X second light-emitting units 110b to share the first power line 140a, thereby eliminating load fluctuations on each first power line 140a.

[0060] In some embodiments, the first control circuit 120 includes five first transistors, the first ends of the five first transistors are all connected to the first power supply 210, the second end of the first first transistor 121 is connected to the fifth light-emitting unit 115, the second end of the second first transistor 122 is connected to the fourth light-emitting unit 114, the second end of the third first transistor 123 is connected to the third light-emitting unit 113, the second end of the fourth first transistor 124 is connected to the second light-emitting unit 112, the second end of the fifth first transistor 125 is connected to the first light-emitting unit 111, and the control ends of the five first transistors are respectively connected to the control unit 300.

[0061] The second control circuit 130 includes five second transistors, the first end of the first second transistor 131, the first end of the second second transistor 132, and the first end of the fourth second transistor 134 are all connected to the seventh light-emitting unit 117, the second end of the first second transistor 131 is connected to the fifth light-emitting unit 115, the second end of the second second transistor 132 is connected to the fourth light-emitting unit 114, the second end of the fourth second transistor 134 is connected to the second light-emitting unit 112, the first end of the third second transistor 133 and the first end of the fifth second transistor 135 are both connected to the sixth light-emitting unit 116, the second end of the third second transistor 133 is connected to the third light-emitting unit 113, and the second end of the fifth second transistor 135 is connected to the first light-emitting unit 111. The control ends of the five second transistors are respectively connected to the control unit 300.

[0062] See also Figures 4 to 6 As shown, in the narrow viewing angle mode, the control unit 300 outputs a pulse width modulation signal to control the turning on and off of the first transistor and the second transistor.

[0063] The fourth first transistor 124 is controlled to be turned on and the fourth second transistor 134 is controlled to be turned off. When the on-duty cycle of the second light-emitting unit 112 is 55%, the fourth first transistor 124 is controlled to be turned off and the fourth second transistor 134 is controlled to be turned on. During the period when the second light-emitting unit 112 is turned off, the seventh light-emitting unit 117 uses the first power line 140a of the second light-emitting unit 112 to conduct the second power supply until the on-duty cycle of the seventh light-emitting unit 117 reaches 45%.

[0064] The second first transistor 122 is controlled to be off and the second second transistor 132 is controlled to be on until the off duty cycle of the fourth light-emitting unit 114 reaches 30%. The second first transistor 122 is controlled to be on and the second second transistor 132 is controlled to be off until the on duty cycle of the fourth light-emitting unit 114 reaches 70%. The second first transistor 122 is controlled to be off and the second second transistor 132 is controlled to be on. During the off period of the fourth light-emitting unit 114, the seventh light-emitting unit 117 uses the first power line 140a of the fourth light-emitting unit 114 to conduct the second power supply until the on duty cycle of the seventh light-emitting unit 117 reaches 30%.

[0065] The first transistor 121 is controlled to be off and the first second transistor 131 is controlled to be on until the off duty cycle of the fifth light-emitting unit 115 reaches 50%. The first transistor 121 is controlled to be on and the first second transistor 131 is controlled to be off until the on duty cycle of the fifth light-emitting unit 115 reaches 80%. The first transistor 121 is then controlled to be off and the first second transistor 131 is controlled to be on. During the off period of the fifth light-emitting unit 115, the seventh light-emitting unit 117 uses the first power line 140a of the fifth light-emitting unit 115 to conduct the second power supply until the on duty cycle of the seventh light-emitting unit 117 reaches 20%. At this time, the total on duty cycle of the seventh light-emitting unit 117 reaches 95%.

[0066] The fifth first transistor 125 is controlled to be turned on and the fifth second transistor 135 is controlled to be turned off. When the on-duty cycle of the first light-emitting unit 111 reaches 50%, the fifth first transistor 125 is controlled to be turned off and the fifth second transistor 135 is controlled to be turned on. During the period when the first light-emitting unit 111 is turned off, the sixth light-emitting unit 116 uses the first power line 140a of the first light-emitting unit 111 to conduct the second power supply until the on-duty cycle of the sixth light-emitting unit 116 reaches 50%.

[0067] The third first transistor 123 is controlled to be turned off and the third second transistor 133 is controlled to be turned on until the off duty cycle of the third light-emitting unit 113 reaches 40%. The third first transistor 123 is controlled to be turned on and the third second transistor 133 is controlled to be turned off until the on duty cycle of the third light-emitting unit 113 reaches 60%. The third first transistor 123 is then controlled to be turned off and the third second transistor 133 is controlled to be turned on. During the period when the third light-emitting unit 113 is turned off, the sixth light-emitting unit 116 uses the first power line 140a of the third light-emitting unit 113 to turn on the second power supply until the on duty cycle of the sixth light-emitting unit 116 reaches 40%. At this time, the total on duty cycle of the sixth light-emitting unit 116 reaches 90%.

[0068] By controlling the on or off of the seven light-emitting units 110 through five first transistors and five second transistors, the load on each first power line 140a can be made equal, and the load on the first power line 140a is also equal to the load on the second power line 140b, eliminating load fluctuations on the first power line 140a.

[0069] In some embodiments, the first transistor is a P-type transistor, and the second transistor is an N-type transistor.

[0070] The first transistor is a P-type transistor and the second transistor is an N-type transistor. The five first transistors and the five second transistors can be controlled by five pulse width modulation signals of the control unit 300, which can simplify the structure of the control unit 300.

[0071] It should be noted that the first transistor is a P-type transistor and the second transistor is an N-type transistor, but is not limited thereto. The first transistor and the second transistor may both be P-type transistors or N-type transistors, depending on the specific situation.

[0072] In some embodiments, the backlight module 100 further includes a third control circuit, such as Figure 7 As shown, the third control circuit includes at least one third transistor 151. Each first light-emitting unit 110a except the Nth light-emitting unit 110 is connected to a first terminal of each third transistor 151. A second terminal of each third transistor 151 is connected to the second power supply via a second power line 140b. A control terminal of each third transistor 151 is connected to the control unit 300. For example, if N is 8, the seventh light-emitting unit 117 is connected to a second power line 140b via a third transistor 151, and the sixth light-emitting unit 116 is also connected to a second power line 140b via a third transistor 151.

[0073] In the wide viewing angle mode, the control unit 300 may control all the third transistors 151 to be turned on and all the first transistors to be turned on, so that the duty cycle of each light emitting unit 110 is 100%.

[0074] In some embodiments, the backlight module 100 includes 2N backlight partitions 101. In the first direction, the first N backlight partitions 101 and the last N backlight partitions 101 are symmetrically arranged. The control unit 300 can output a pulse width modulation signal in a narrow viewing angle mode, so that the brightness of the 2N backlight partitions 101 gradually increases and then gradually decreases along the first direction.

[0075] The brightness of the 2N backlight subareas 101 gradually increases and then gradually decreases along the first direction, so that the backlight module 100 and the display device can achieve double-sided privacy protection.

[0076] In some embodiments, the light-emitting units 110 of the symmetrically arranged backlight sub-areas 101 are connected in series, with the boundary between the Nth backlight sub-area 101 and the N+1th backlight sub-area 101 as the center of symmetry. The two series-connected light-emitting units 110 are connected as a whole between the first power supply 210 and the second power supply. For example, N is 8, the light-emitting units 110 of the first backlight sub-area 101 and the light-emitting units 110 of the 16th backlight sub-area 101 are connected in series. The light-emitting units 110 of the first backlight sub-area 101 are connected to the first power supply 210 via the first control circuit 120, and the light-emitting units 110 of the 16th backlight sub-area 101 are connected to the second power supply via the second control circuit 130 and the first power line 140a.

[0077] The light-emitting units 110 of the symmetrically arranged backlight subareas 101 are connected in series, which can simplify the structure of the backlight module 100 and reduce the manufacturing cost of the backlight module 100 .

[0078] It should be noted that the light-emitting units 110 of the symmetrically arranged backlight partitions 101 are connected in series, but are not limited to this. The same first control circuit 120, second control circuit 130 and third control circuit can also be set for the light-emitting units 110 of the symmetrically arranged backlight partitions 101, and the specific details can be determined according to the circumstances.

[0079] Example 2

[0080] This application also provides a display device, see Figure 8 As shown, the display device in this embodiment includes the backlight module 100 disclosed in the first embodiment and a control unit 300. The control unit 300 is connected to the first control circuit 120 and the second control circuit 130, and the control unit 300 includes a timing controller (TCON). The display device also includes a driver chip 200, which is a power management chip (PMIC) that provides a first power supply 210 and a second power supply.

[0081] In this embodiment, the display device includes a backlight module 100, which includes at least N backlight partitions 101. Each backlight partition 101 is provided with a light-emitting unit 110. The backlight module 100 also includes a first control circuit 120 and a second control circuit 130. The first light-emitting unit 110a is directly connected to the first power supply 210, and the second light-emitting unit 110b is indirectly connected to the first power supply 210 through the first control circuit 120. Each second light-emitting unit 110b is connected to the second power supply through a first power line 140a. At least one first light-emitting unit 110a is connected to X first power lines 140a through the second control circuit 130. The first control circuit 120 and the second control circuit 130 are also connected to a control unit 300. The control unit 300 can output a pulse width modulation signal in a narrow viewing angle mode to gradually increase or decrease the brightness of the N backlight partitions 101 along a first direction to achieve an anti-peeping function. Because the sum of the off-duty cycles of the second light-emitting units 110b connected to the X first power lines 140a is equal to the on-duty cycle of the first light-emitting units 110a connected to the X first power lines 140a, some of the first light-emitting units 110a and some of the second light-emitting units 110b can share the first power line 140a, thereby improving or eliminating the problem of unstable boosting operation of the driver chip 200 and enhanced electromagnetic interference caused by load fluctuations on the X first power lines 140a.

[0082] The terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature identified with "first," "second," etc., may explicitly or implicitly include one or more of such features. Throughout the description of this application, "plurality" means two or more, unless otherwise specifically defined.

[0083] In this application, unless otherwise specified or limited, terms such as "assembly" and "connection" should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection; direct connection, or indirect connection through an intermediate medium; internal communication between two components, or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0084] In the description of this specification, the reference terms "some embodiments", "exemplarily", etc. mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.

[0085] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application. Therefore, any changes or modifications made in accordance with the claims and description of the present application should fall within the scope of the patent application.

Claims

1. A backlight module comprising at least N backlight sub-areas, wherein the N backlight sub-areas are arranged in sequence along a first direction, N being greater than or equal to 3, and each backlight sub-area is provided with a light-emitting unit, characterized in that: The backlight module further includes: a first control circuit, wherein the N light-emitting units are divided into a first light-emitting unit and a second light-emitting unit, the first light-emitting unit is directly connected to a first power source, and the second light-emitting unit is indirectly connected to the first power source via the first control circuit; a second control circuit, wherein each of the second light-emitting units is connected to a second power source via a first power line, and at least one of the first light-emitting units is connected to X first power lines via the second control circuit, where X is greater than or equal to 2; the first control circuit and the second control circuit are further connected to a control unit, and the control unit is capable of outputting a pulse width modulation signal in a narrow viewing angle mode, and controlling the on-duty cycle or off-duty cycle of at least some of the light-emitting units by controlling the on-duty cycle or off-duty cycle of at least some of the light-emitting units so that the brightness of the N backlight subareas gradually increases or decreases along the first direction by controlling the on-duty cycle or off-duty cycle of the light-emitting units and the first power source and the second power source; The sum of the off duty cycles of the second light-emitting units connected to the X first power lines is equal to the on duty cycles of the first light-emitting units connected to the X first power lines. In the narrow viewing angle mode, the load on each first power line is equal.

2. The backlight module according to claim 1, wherein: The Nth light-emitting unit along the first direction is the first light-emitting unit, the Nth light-emitting unit is directly connected to the first power supply and to the second power supply through a second power supply line, and the turn-on duty cycle of the Nth light-emitting unit is 100%.

3. The backlight module according to claim 2, wherein: Each of the first light-emitting units except the Nth light-emitting unit is connected to X first power lines through the second control circuit, and the number of the first power lines connected to each first light-emitting unit is the same or different.

4. The backlight module according to claim 3, wherein: N is equal to 8, the turn-on duty cycle of the first light-emitting unit is 50%, the turn-on duty cycle of the second light-emitting unit is 55%, the turn-on duty cycle of the third light-emitting unit is 60%, the turn-on duty cycle of the fourth light-emitting unit is 70%, the turn-on duty cycle of the fifth light-emitting unit is 80%, the turn-on duty cycle of the sixth light-emitting unit is 90%, the turn-on duty cycle of the seventh light-emitting unit is 95%, and the turn-on duty cycle of the eighth light-emitting unit is 100%.

5. The backlight module according to claim 4, wherein: The first control circuit includes five first transistors, wherein the first ends of the five first transistors are all connected to the first power supply, the second end of the first first transistor is connected to the fifth light-emitting unit, the second end of the second first transistor is connected to the fourth light-emitting unit, the second end of the third first transistor is connected to the third light-emitting unit, the second end of the fourth first transistor is connected to the second light-emitting unit, and the second end of the fifth first transistor is connected to the first light-emitting unit, and the control ends of the five first transistors are respectively connected to the control unit; The second control circuit includes five second transistors, the first end of the first second transistor, the first end of the second second transistor, and the first end of the fourth second transistor are all connected to the seventh light-emitting unit, the second end of the first second transistor is connected to the fifth light-emitting unit, the second end of the second second transistor is connected to the fourth light-emitting unit, the second end of the fourth second transistor is connected to the second light-emitting unit, the first end of the third second transistor and the first end of the fifth second transistor are both connected to the sixth light-emitting unit, the second end of the third second transistor is connected to the third light-emitting unit, and the second end of the fifth second transistor is connected to the first light-emitting unit. The control ends of the five second transistors are respectively connected to the control unit.

6. The backlight module according to claim 5, wherein: The first transistor is a P-type transistor, and the second transistor is an N-type transistor.

7. The backlight module according to claim 3, wherein: The backlight module also includes a third control circuit, which includes at least one third transistor. Each of the first light-emitting units except the Nth light-emitting unit is connected to the first end of each third transistor, and the second end of each third transistor is connected to the second power supply through a second power line. The control end of each third transistor is connected to the control unit.

8. The backlight module according to claim 1, wherein: The backlight module includes 2N backlight partitions. In the first direction, the first N backlight partitions and the last N backlight partitions are symmetrically arranged. The control unit can output a pulse width modulation signal in a narrow viewing angle mode, so that the brightness of the 2N backlight partitions gradually increases and then gradually decreases along the first direction.

9. The backlight module according to claim 8, wherein: The light-emitting units of the symmetrically arranged backlight partitions are connected in series with a boundary line between the Nth backlight partition and the N+1th backlight partition as a symmetric center.

10. A display device, characterized in that: include: The backlight module according to any one of claims 1 to 9; A control unit is connected to the first control circuit and the second control circuit, and the control unit includes a timing controller.

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