Patent Publication Number: US-2022236595-A1

Title: Display device, backlight source, and automobile

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
     This application claims priority to Chinese Patent Application No. 202111668245.8 filed with the China National Intellectual Property Administration (CNIPA) on Dec. 31, 2021, the disclosure of which is incorporated herein by reference in its entirety. 
     TECHNICAL FIELD 
     The present disclosure relates to the field of display technologies, in particular to a display device, a backlight source and an automobile. 
     BACKGROUND 
     At present, people have different requirements for view angles of display products in different occasions. For example, when the content of a display picture may be seen by many people at different angles, the display product is required to have a wide view angle, namely a sharing state; and when the content of the display picture is kept secret and is visible only by a user himself/herself, the display product is required to have a narrow-view-angle function, namely a peep-proof state. 
     During the switch between the sharing state and the peep-proof state, the change of the brightness which may be distinguished by human eyes occurs, so that the human eyes can recognize a switching process of the sharing state and the peep-proof state, and thus the human eyes are prone to fatigue. 
     SUMMARY 
     The present disclosure provides a display device, a backlight source and an automobile, to gradually change the brightness at each view angle and avoid the abrupt change of the display brightness of the display device during the switch between a sharing mode phase and a privacy mode phase, so that the fatigue of human eyes is improved. 
     In a first aspect, an embodiment of the present disclosure provides a display device. The display device includes a view angle control panel, where the view angle control panel includes a view angle liquid crystal layer, a first electrode and a second electrode; the view angle liquid crystal layer includes a liquid crystal molecule, and the liquid crystal molecule is driven to rotate by an electric field generated between the first electrode and the second electrode. In a sharing mode phase, a same voltage is provided for the first electrode and the second electrode. In a privacy mode phase, a first voltage is provided for the first electrode, and an alternating voltage signal is provided for the second electrode, where a high voltage of the alternating voltage signal is greater than the first voltage, and a low voltage of the alternating voltage signal is less than the first voltage. In a transition phase, the first voltage is provided for the first electrode, and a voltage signal with gradually changing duty cycles is provided for the second electrode; where the transition phase is located between the sharing mode phase and the privacy mode phase, and a duty cycle is a ratio of time occupied by a pulse within a period of continuous operating time to the period of continuous operating time. 
     In a second aspect, an embodiment of the present disclosure provides a backlight source. The backlight source includes a first light source and a second light source; in a sharing mode phase, the second light source is turned on; in a privacy mode phase, the first light source is turned on, and the second light source is turned off; and in a transition phase, a voltage signal with gradually changing duty cycles is provided for the second light source, where the transition phase is located between the sharing mode phase and the privacy mode phase, and a duty cycle is a ratio of time occupied by a pulse within a period of continuous operating time to the period of continuous operating time. 
     In a third aspect, an embodiment of the present disclosure provides a display device. The display device includes the backlight source described in the second aspect and a liquid crystal display panel, where the liquid crystal display panel is disposed on a light-emitting side of the backlight source. 
     In a fourth aspect, an embodiment of the present disclosure provides an automobile. The automobile includes the display device described in the first aspect, or the display device described in the third aspect. 
     In the display device provided in the embodiments of the present disclosure, the transition phase is additionally set between the sharing mode phase and the privacy mode phase, and in the transition phase, the first voltage is provided for the first electrode, and the voltage signal with the gradually changing duty cycles is provided for the second electrode. Thus, an electric field with gradually changed intensities is generated between the first electrode and the second electrode, and the liquid crystal molecule is driven to gradually rotate, so as to gradually change the brightness at each view angle and avoid the abrupt change of the display brightness of the display device during the switch between the sharing mode phase (namely, the sharing state) and the privacy mode phase (namely, the peep-proof state). Therefore, the fatigue of the human eyes is improved. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a schematic diagram of a display device in a sharing mode phase according to an embodiment of the present disclosure; 
         FIG. 2  is a schematic diagram of the display device shown in  FIG. 1  in a privacy mode phase; 
         FIG. 3  is a timing diagram of a display device according to an embodiment of the present disclosure; 
         FIG. 4  is a timing diagram of another display device according to an embodiment of the present disclosure; 
         FIG. 5  is a timing diagram of another display device according to an embodiment of the present disclosure; 
         FIG. 6  is a timing diagram of another display device according to an embodiment of the present disclosure; 
         FIG. 7  is a timing diagram of another display device according to an embodiment of the present disclosure; 
         FIG. 8  is a cross-sectional view of another display device according to an embodiment of the present disclosure; 
         FIG. 9  is a cross-sectional view of another display device according to an embodiment of the present disclosure; 
         FIG. 10  is a cross-sectional view of another display device according to an embodiment of the present disclosure; 
         FIG. 11  is a top view of another display device according to an embodiment of the present disclosure; 
         FIG. 12  is a circuit schematic diagram of a driver circuit according to an embodiment of the present disclosure; 
         FIG. 13  is a timing diagram of a voltage signal alternating around a reference voltage according to an embodiment of the present disclosure; 
         FIG. 14  is a cross-sectional view of another display device according to an embodiment of the present disclosure; 
         FIG. 15  is a cross-sectional view of another display device according to an embodiment of the present disclosure; 
         FIG. 16  is a cross-sectional view of another display device according to an embodiment of the present disclosure; 
         FIG. 17  is a cross-sectional view of another display device according to an embodiment of the present disclosure; 
         FIG. 18  is a top view of a backlight source according to an embodiment of the present disclosure; 
         FIG. 19  is a cross-sectional view taken along AA′ of  FIG. 18 ; 
         FIG. 20  is a timing diagram of a backlight source according to an embodiment of the present disclosure; 
         FIG. 21  is a timing diagram of another backlight source according to an embodiment of the present disclosure; 
         FIG. 22  is a timing diagram of another backlight source according to an embodiment of the present disclosure; 
         FIG. 23  is a timing diagram of another backlight source according to an embodiment of the present disclosure; 
         FIG. 24  is a top view of another backlight source according to an embodiment of the present disclosure; 
         FIG. 25  is a cross-sectional view of another backlight source according to an embodiment of the present disclosure; and 
         FIG. 26  is a schematic diagram of an automobile according to an embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     The present disclosure will be further described in detail in conjunction with the drawings and embodiments below. It should be understood that the specific embodiments described herein are merely used for explaining the present disclosure and are not intended to limit the present disclosure. It should also be noted that, for ease of description, only part, but not all, of the structures related to the present disclosure are shown in the drawings. 
       FIG. 1  is a schematic diagram of a display device in a sharing mode phase according to an embodiment of the present disclosure,  FIG. 2  is a schematic diagram of the display device shown in  FIG. 1  in a privacy mode phase, and  FIG. 3  is a timing diagram of a display device according to an embodiment of the present disclosure. With reference to  FIGS. 1 to 3 , the display device includes a view angle control panel  100 , and the view angle control panel  100  includes a view angle liquid crystal layer  21 , a first electrode  11  and a second electrode  12 . The view angle liquid crystal layer  21  includes liquid crystal molecules  211 . The liquid crystal molecules  211  are driven to rotate by an electric field generated between the first electrode  11  and the second electrode  12 . 
     In the sharing mode phase, a same voltage is provided for the first electrode  11  and the second electrode  12 . For example, a first voltage is provided for both the first electrode  11  and the second electrode  12 , no electric field is formed between the first electrode  11  and the second electrode  12 , and the liquid crystal molecules  211  do not rotate. The emitting brightness of the light at each view angle is the same or approximate, and the case where the brightness of the light at a certain view angle range is rapidly reduced does not occur. A picture displayed by the display device may be viewed by human eyes at various view angles. 
     In the privacy mode phase, the first voltage is provided for the first electrode  11 , and an alternating voltage signal is provided for the second electrode  12 , where a high voltage of the alternating voltage signal is greater than the first voltage, and a low voltage of the alternating voltage signal is less than the first voltage. An electric field is generated between the first electrode  11  and the second electrode  12  to drive the liquid crystal molecules  211  to rotate, causing that the light brightness of the display device on a first side is rapidly reduced, and a picture displayed by the display device cannot be viewed by human eyes on the first side. The light brightness of the display device on a second side is not reduced or slightly reduced, and a picture displayed by the display device may be viewed by human eyes on the second side. The first side is opposite to the second side. For example, the first side may be the left side, and the second side is the right side. The alternating voltage signal is a voltage signal which fluctuates up and down around a common, and in one waveform period, the alternating voltage signal has a high voltage which is greater than the first voltage and a low voltage which is less than the first voltage. In multiple waveform periods, there are high voltage, low voltage, high voltage, low voltage and so on in sequence. That is, adjacent high voltages are spaced by one low voltage, and adjacent low voltages are spaced by one high voltage. The first voltage may be a common voltage (0V), a positive voltage, or a negative voltage. In some implementations, a voltage provided for the first electrode  11  in the privacy mode phase may also be different from a voltage provided for the first electrode  11  in the sharing mode phase. 
     In the transition phase, the first voltage is provided for the first electrode  11 , and a voltage signal with gradually changing duty cycles is provided for the second electrode  12 . The transition phase is located between the sharing mode phase and the privacy mode phase, and a duty cycle is a ratio of time occupied by a pulse within a period of continuous operating time to the period of continuous operating time. The voltage signal with the gradually changing duty cycles may be the alternating voltage signal. 
     In the display device provided in the embodiments of the present disclosure, the transition phase is additionally set between the sharing mode phase and the privacy mode phase, and in the transition phase, the first voltage is provided for the first electrode  11 , and the voltage signal with the gradually changing duty cycles is provided for the second electrode  12 , so that an electric field with gradually changing intensities is generated between the first electrode  11  and the second electrode  12 , and the liquid crystal molecules  211  are driven to gradually rotate. Therefore, the brightness at each view angle is gradually changed, and the abrupt change of the display brightness of the display device during the switch between the sharing mode phase (namely, a sharing state) and the privacy mode phase (namely, a peep-proof state) is avoided, and thus the fatigue of the human eyes is improved. 
     As shown in  FIG. 3 , there are differences in timing waveforms of the sharing mode phase, the transition phase, and the privacy mode phase, causing the view angle differences in display brightness of the display device. In an actual display device product, the sharing mode phase, the transition phase, and the privacy mode phase may be achieved by the control of the voltage applied to the second electrode  12 . In the sharing mode phase, the first voltage is provided for the second electrode  12 . In the transition phase, the voltage provided for the second electrode  12  includes the high voltage, the low voltage and the first voltage, and a gradual change of the duty cycle is achieved by controlling a ratio of the high voltage in the waveform period and a ratio of the low voltage in the waveform period. In the privacy mode phase, the high voltage and the low voltage are provided for the second electrode  12 , the pulses occupy all of the waveform period and the duty cycle is 100%. 
     In an embodiment, with reference to  FIG. 3 , in the transition phase during which the sharing mode phase is switched to the privacy mode phase, a voltage signal with gradually increasing duty cycles is provided for the second electrode  12 . In the sharing mode phase, the first voltage is provided for the second electrode  12 , no pulses exist, and the duty cycle is 0%. In the transition phase, a voltage signal with gradually increasing duty cycles is provided for the second electrode  12 . For example, a voltage signal with a duty cycle of 20%, 40%, 60%, and 80% in sequence is provided. In the privacy mode phase, a signal with a duty cycle of 100% is provided for the second electrode  12 . Therefore, during the change from the sharing mode phase to the transition phase and then from the transition phase to the privacy mode phase, duty cycles of signals provided for the second electrode  12  gradually increase, a gradually enhanced electric field is generated between the first electrode  11  and the second electrode  12 , and the liquid crystal molecules  211  are driven to gradually rotate, so that the view angle is gradually narrowed, and the abrupt change of the display brightness of the display device is avoided, and thus the fatigue of the human eyes is improved. 
     Exemplarily, the duration of each waveform period is equal, i.e., each waveform period has the same length of time. Multiple waveform periods of the transition phase are sequentially denoted as a first period T 1 , a second period T 2 , a third period T 3  and a fourth period T 4 . A duty cycle of the first period T 1  is less than a duty cycle of the second period T 2 . The duty cycle of the second period T 2  is less than a duty cycle of the third period T 3 , and the duty cycle of the third period T 3  is less than a duty cycle of the fourth period T 4 . 
       FIG. 4  is a timing diagram of another display device according to an embodiment of the present disclosure. With reference to  FIG. 4 , in the transition phase during which the privacy mode phase is switched to the sharing mode phase, a voltage signal with gradually decreasing duty cycles is provided for the second electrode  12 . In the privacy mode phase, a signal with a duty cycle of 100% is provided for the second electrode  12 . In the transition phase, a voltage signal with gradually decreasing duty cycles is provided for the second electrode  12 . For example, a voltage signal with a duty cycle of 80%, 60%, 40%, and 20% in sequence is provided. In the sharing mode phase, a signal with a duty cycle of 0% is provided for the second electrode  12 . Therefore, during the change from the privacy mode phase to the transition phase and then from the transition phase to the sharing mode phase, duty cycles of signals provided for the second electrode  12  gradually decrease, and a gradually weakened electric field is generated between the first electrode  11  and the second electrode  12 , and the liquid crystal molecules  211  are driven to gradually rotate, so that the view angle is gradually broaden, and the abrupt change of the display brightness of the display device is avoided, and thus the fatigue of the human eyes is improved. 
     Exemplarily, the duty cycle of the first period T 1  is greater than the duty cycle of the second period T 2 . The duty cycle of the second period T 2  is greater than the duty cycle of the third period T 3 . The duty cycle of the third period T 3  is greater than the duty cycle of the fourth period T 4 . 
     It should be noted that the voltage signal with the gradually changing duty cycles is a voltage signal with gradually increasing or decreasing duty cycles as a whole. At least two adjacent waveform periods may have the same duty cycle. 
       FIG. 5  is a timing diagram of another display device according to an embodiment of the present disclosure. With reference to  FIG. 5 , multiple waveform periods of the transition phase are sequentially denoted as a first period T 1 , a second period T 2 , a third period T 3 , a fourth period T 4 , and a fifth period T 5 . A duty cycle of the first period T 1  is equal to a duty cycle of the second period T 2 . The duty cycle of the second period T 2  is less than a duty cycle of the third period T 3 . The duty cycle of the third period T 3  is less than a duty cycle of the fourth period T 4 . The duty cycle of the fourth period T 4  is less than a duty cycle of the fifth period T 5 . 
     In an implementation, multiple waveform periods may constitute a group, waveform periods within a same group have the same duty cycle, and waveform periods within different groups have different duty cycles. 
       FIG. 6  is a timing diagram of another display device according to an embodiment of the present disclosure. With reference to  FIG. 6 , multiple groups of the transition phase are sequentially denoted as a first group G 1 , a second group G 2 , and a third group G 3 . The first group G 1  includes a first period T 1  and a second period T 2  set in sequence. The second group G 2  includes a third period T 3  and a fourth period T 4  set in sequence. The third group G 3  includes a fifth period T 5  and a sixth period T 6  set in sequence. A duty cycle of the first period T 1  is equal to a duty cycle of the second period T 2 , a duty cycle of the third period T 3  is equal to a duty cycle of the fourth period T 4 , and a duty cycle of the fifth period T 5  is equal to a duty cycle of the sixth period T 6 . The duty cycle of the second period T 2  is less than the duty cycle of the third period T 3 . The duty cycle of the fourth period T 4  is less than the duty cycle of the fifth period T 5 . 
     In an embodiment, with reference to  FIGS. 3 to 6 , in the transition phase, a square wave signal with gradually changing duty cycles is provided for the second electrode  12 . In other implementations, voltage signals with other waveforms may also be provided for the second electrode  12  in the transition phase. 
       FIG. 7  is a timing diagram of another display device according to an embodiment of the present disclosure. With reference to  FIG. 7 , in the transition phase, the waveform provided for the second electrode  12  includes a curve. 
     Referring to  FIGS. 3 to 6 , in the transition phase or the privacy mode phase, alternating high and low voltages are provided for the second electrode  12 , and thus it is avoided that the drive voltage of the liquid crystal molecules  211  is fixed at a certain fixed value. Further, a maintaining duration of the high voltage is equal to a maintaining duration of the low voltage in a same waveform period, and a rotation angle of the liquid crystal molecules  211  driven by an electric field generated by the high voltage and the first voltage is equal to a rotation angle of the liquid crystal molecules  211  driven by an electric field generated by the low voltage and the first voltage, but directions of the liquid crystal molecules  211  are opposite, so that the polarization of the liquid crystal molecules  211  is avoided. 
       FIG. 8  is a cross-sectional view of another display device according to an embodiment of the present disclosure. With reference to  FIG. 8 , the view angle liquid crystal layer  21  includes liquid crystal molecules  211  and dye molecules  212 . When an electric field generated between the first electrode  11  and the second electrode  12  drives the liquid crystal molecules  211  to rotate, the dye molecules  212  are driven to rotate, that is, the dye molecules  212  rotate according to the rotation of the liquid crystal molecules  211 . The light whose polarization direction is parallel to a long axis direction of the dye molecules  212  is absorbed by the dye molecules  212 , and the light whose polarization direction is perpendicular to the long axis direction of the dye molecules  212  is not absorbed by the dye molecules  212 . 
     As shown in  FIG. 8 , the electric field generated between the first electrode  11  and the second electrode  12  drives the liquid crystal molecules  211  to rotate, the polarization direction of the light emitted toward the left side is parallel or approximately parallel to the long axis direction of the dye molecules  212 , and the light is absorbed by the dye molecules  212 , so that a picture displayed by the display device cannot be viewed by the human eyes on the left side. The polarization direction of the light emitted toward the right side is perpendicular or approximately perpendicular to the long axis direction of the dye molecules  212 , and the light is not absorbed by the dye molecules  212 , so that a picture displayed by the display device may be viewed by the human eyes on the right side. 
       FIG. 9  is a cross-sectional view of another display device according to an embodiment of the present disclosure. With reference to  FIG. 9 , the second electrode  12  includes multiple sub-electrodes  121  arranged in an array. The view angle control panel  100  further includes a voltage gradient conversion circuit (not shown in  FIG. 9 ), and the voltage gradient conversion circuit is configured to provide a voltage signal with a reduced gradient for multiple sub-electrodes  121  arranged in a first direction. For the multiple sub-electrodes  121  arranged in the first direction, an electric field generated between the sub-electrodes  121  and the first electrode  11  gradually decreases, so that the rotation angle of the liquid crystal molecules  211  gradually decreases in the first direction. The light emitted toward the left side is absorbed by the dye molecules  212 . The light emitted toward the right side is not absorbed by the dye molecules  212 . The voltage applied to the sub-electrode  121  on the right side is less than the voltage applied to the sub-electrode  121  on the left side, which reduces the power consumption of the display device. 
       FIG. 10  is a cross-sectional view of another display device according to an embodiment of the present disclosure. With reference to  FIG. 10 , the first electrode  11  includes multiple counter sub-electrodes  111 , and the counter sub-electrodes  111  are disposed opposite to the sub-electrodes  121 . When the first voltage is provided for the first electrode  11 , the first voltage is provided for all the counter sub-electrodes  111  at the same time. 
       FIG. 11  is a top view of another display device according to an embodiment of the present disclosure,  FIG. 12  is a circuit schematic diagram of a driver circuit according to an embodiment of the present disclosure, and  FIG. 13  is a timing diagram of a voltage signal alternating around a reference voltage according to an embodiment of the present disclosure. With reference to  FIGS. 11, 12 and 13 , the display device further includes a driver circuit  400 . The driver circuit  400  includes a comparator  410 , a non-inverting input terminal of the comparator  410  is configured to input a reference voltage Vref, and a voltage signal input by an inverting input terminal of the comparator  410  is configured to alternate around the reference voltage Vref, and an output terminal of the comparator  410  is configured to output a voltage signal with gradually changing duty cycles in the transition phase 
     In  FIG. 11 , in order to illustrate the overlapping first electrode  11  and second electrode  12 , the first electrode  11  and the second electrode  12  are staggered at a certain interval in the first direction. In an actual display device, the first electrode  11  and the second electrode  12  may be staggered at a certain interval in the first direction, or may overlap with each other without being staggered in the first direction. Referring to  FIGS. 11 to 13 , the view angle control panel  100  further includes a voltage gradient conversion circuit  110 , the output terminal of the comparator  410  may be electrically connected to the voltage gradient conversion circuit  110 , and a voltage signal output by the output terminal of the comparator  410  is processed by the voltage gradient conversion circuit  110  and then applied to multiple sub-electrodes  121  arranged in an array. In the transition phase, a voltage signal with gradually changing duty cycles is applied to each sub-electrode  121 . Exemplarily, with reference to  FIG. 11 , the voltage gradient conversion circuit  110  includes multiple voltage regulating units  1101 , a first terminal of the voltage regulating unit  1101  is electrically connected to the output terminal of the comparator  410 , a second terminal of the voltage regulating unit  1101  is connected to ground, and an output terminal of the voltage regulating unit  1101  is electrically connected to the second electrode  12 , so that the voltage of the second electrode  12  electrically connected to the voltage regulating unit  1101  can be regulated by the voltage regulating unit  1101 . 
     Exemplarily, with reference to  FIG. 11 , the voltage regulating unit  1101  includes a first resistor R 1  and a second resistor R 2 , a first terminal of the first resistor R 1  is electrically connected to the output terminal of the comparator  410 , a second terminal of the first resistor R 1  is electrically connected to a first terminal of the second resistor R 2 , and a second terminal of the second resistor R 2  is connected to ground. The second terminal of the first resistor R 1  is electrically connected to the second electrode  12 , so that a voltage provided by the second electrode  12  can be changed by regulating resistance values of the first resistor R 1  and the second resistor R 2 . 
     In another implementation, the output terminal of the comparator  410  may be directly electrically connected to the second electrode  12  to apply a voltage signal with gradually changing duty cycles to the second electrode  12  in the transition phase. 
     Exemplarily, with reference to  FIGS. 11, 12 and 13 , the driver circuit  400  includes a bias voltage providing device  420 , a third resistor R 3  and a fourth resistor R 4 , an input terminal of the bias voltage providing device  420  is electrically connected to a first power supply terminal V 1 , and a control terminal of the bias voltage providing device  420  is electrically connected to an enable terminal EN. A first output terminal of the bias voltage providing device  420  is electrically connected to a first power input terminal of the comparator  410  for providing a positive bias voltage for the comparator  410 . A second output terminal of the bias voltage providing device  420  is electrically connected to a second power supply input terminal of the comparator  410  for providing a negative bias voltage for the comparator  410 . A first terminal of the third resistor R 3  is electrically connected to the first power supply terminal V 1 , a second terminal of the third resistor R 3  is electrically connected to a first terminal of the fourth resistor R 4 , and a second terminal of the fourth resistor R 4  is connected to ground. The second terminal of the third resistor R 3  is electrically connected to a non-inverting input terminal of the comparator  410 , and a resistor string formed by the third resistor R 3  and the fourth resistor R 4  is configured to provide a reference voltage Vref. An inverting input terminal of the comparator  410  is electrically connected to the second power supply terminal V 2 . In an implementation, the second power supply terminal V 2  may be electrically connected to a driver chip, i.e., a voltage signal is provided for the inverting input terminal of the comparator  410  via the driver chip. 
       FIG. 14  is a cross-sectional view of another display device according to an embodiment of the present disclosure. With reference to  FIG. 14 , the display device includes a view angle control panel  100  and a display panel  200 , and the view angle control panel  100  is disposed on a light-emitting display side of the display panel  200 . The light emitted by the display panel  200  irradiates on the view angle control panel  100 , and the brightness of the light at each view angle is changed by the view angle control panel  100 , so that the privacy mode phase, the transition phase and the sharing mode phase are achieved. 
     In an embodiment, the display panel includes a display panel known in the art, such as a liquid crystal display panel, an organic light-emitting display panel, or a micro light-emitting diode display panel. The organic light-emitting display panel and the micro light-emitting diode display panel are self-light-emitting display panels that do not need a backlight source, so that the display device is lighter and thinner. The organic light-emitting display panel includes an organic light-emitting material layer, and the organic light-emitting display panel may further include at least one of a hole injection layer, a hole transport layer, an electron blocking layer, a hole blocking layer, an electron transport layer, or an electron injection layer. The micro light-emitting diode display panel includes a micro light-emitting diode (i.e., u LED), and the micro light-emitting diode has the advantages of smaller size, higher reaction speed, higher light-emitting efficiency, stronger stability, longer service life and the like. 
       FIG. 15  is a cross-sectional view of another display device according to an embodiment of the present disclosure. With reference to  FIG. 15 , the display device includes a view angle control panel  100 , a display panel  200  and a backlight source  300 , the display panel  200  is a liquid crystal display panel, and the backlight source  300  is configured to provide the backlight. The display panel  200  is disposed between the view angle control panel  100  and the backlight source  300 , the light emitted by the backlight source  300  penetrates through the display panel  200  and then irradiates on the view angle control panel  100 , and the brightness of the light at each view angle is changed by the view angle control panel  100 , so that the privacy mode phase, the transition phase and the sharing mode phase are achieved. 
       FIG. 16  is a cross-sectional view of another display device according to an embodiment of the present disclosure. With reference to  FIG. 16 , the view angle control panel  100  is disposed between the display panel  200  and the backlight source  300 . The light emitted by the backlight source  300  irradiates on the view angle control panel  100 , the brightness of the light at each view angle is changed by the view angle control panel  100 , and then the light irradiates on the display panel  200 , so that the privacy mode phase, the transition phase and the sharing mode phase are achieved. 
     Exemplarily, referring to  FIG. 16 , the view angle control panel  100  further includes a first view angle substrate  31  and a second view angle substrate  32 . The first electrode  11 , the second electrode  12 , and the view angle liquid crystal layer  21  are all disposed between the first view angle substrate  31  and the second view angle substrate  32 . 
     Exemplarily, referring to  FIG. 16 , the display panel  200  includes a first display substrate  41 , a second display substrate  42 , and a display liquid crystal layer  22 . The display liquid crystal layer  22  is disposed between the first display substrate  41  and the second display substrate  42 . The display liquid crystal layer  22  includes multiple liquid crystal molecules  211  and the liquid crystal molecules  211  rotate under the drive of an electric field generated by a pixel electrode (not shown in  FIG. 16 ) and a common electrode (not shown in  FIG. 16 ). The display panel  200  may further include a first polarizer  44  and a second polarizer  45 , and the first polarizer  44  is disposed on a side of the first display substrate  41  away from the display liquid crystal layer  22 . The second polarizer  45  is disposed on a side of the second display substrate  42  away from the display liquid crystal layer  22 . A polarization direction of the first polarizer  44  may be perpendicular or parallel to a polarization direction of the second polarizer  45 . 
     In an embodiment, the display device further includes a touch plate  46 , and when the display panel  200  is disposed on a side of the view angle control panel  100  away from the backlight source  300 , the touch plate  46  may also be disposed between the first display substrate  41  and the second display substrate  42 , i.e., the touch plate  46  is integrated into the display panel  200 , so that the thickness of the display device is thinned. In an embodiment, the touch plate  46  may also be disposed on a side of the second polarizer  45  away from the view angle control panel  100 , and in this case, the touch plate  46  includes a substrate and a touch electrode disposed on the substrate. It should be noted that when the touch plate  46  is disposed within a box of the display panel  200 , the touch plate  46  includes only touch electrode, and no additional base substrate is provided, and the touch electrode of the touch electrode is disposed on a side of the base substrate of the display panel  200  facing the liquid crystals. 
     In the above implementations, the view angle control panel has a view angle control function and is configured to control the brightness of the light emitted by the display panel at a specific view angle or control the brightness of the light emitted by the backlight source at a specific view angle, but does not have a display function. In another implementation, the view angle control panel may also have the display function, so that there is no need to additionally provide a display panel for the view angle control panel. 
       FIG. 17  is a cross-sectional view of another display device according to an embodiment of the present disclosure. With reference to  FIG. 17 , the view angle control panel  100  further includes a pixel electrode  13 . The first electrode  11  and the second electrode  12  are disposed on opposite two sides of the view angle liquid crystal layer  21 , and the first electrode  11  and the pixel electrode  13  are disposed on a same side of the view angle liquid crystal layer  21 . 
     Exemplarily, in the sharing mode phase, the first voltage may be applied to the first electrode  11 , the first voltage may be applied to the second electrode  12 , and a corresponding gray-scale voltage may be applied to each pixel electrode  13 , so that the wide-view-angle display is achieved. In the privacy mode phase, the first voltage may be applied to the first electrode  11 , alternating voltages of 3.5V and −3.5V may be applied to the second electrode  12 , and a corresponding gray-scale voltage may be applied to each sub-pixel electrode  13 , so that the narrow-view-angle display may be achieved. The first voltage may be a common voltage (0V), a positive voltage, or a negative voltage. 
     Exemplarily, the display device further includes a third polarizer  47  and a fourth polarizer  48 , and the third polarizer  47  is disposed on a side of the first view angle substrate  31  away from the view angle liquid crystal layer  21 . The fourth polarizer  48  is disposed on a side of the second view angle substrate  32  away from the view angle liquid crystal layer  21 . A polarization direction of the third polarizer  47  may be perpendicular or parallel to a polarization direction of the fourth polarizer  48 . 
       FIG. 18  is a top view of a backlight source according to an embodiment of the present disclosure,  FIG. 19  is a cross-sectional view taken along AA′ of  FIG. 18 , and  FIG. 20  is a timing diagram of a backlight source according to an embodiment of the present disclosure. The backlight source  300  includes a first light source  311  and a second light source  312 . In the sharing mode phase, the second light source  312  is turned on. In the privacy mode phase, the first light source  311  is turned on and the second light source  312  is turned off. In the transition phase, a voltage signal with gradually changing duty cycles is provided for the second light source  312 . The transition phase is located between the sharing mode phase and the privacy mode phase, and the duty cycle is a ratio of time occupied by a pulse within a period of continuous operating time to the period of continuous operating time. 
     An embodiment of the present disclosure provides a backlight source, and the backlight source may be used in the display device of the above embodiments. During the change from the sharing mode phase to the privacy mode phase, the second light source  312  changes from on to off. During the change from the privacy mode phase to the sharing mode phase, the second light source  312  changes from off to on. The transition phase is additionally set between the sharing mode phase and the privacy mode phase, and in the transition phase, a voltage signal with gradually changing duty cycles is provided for the second light source  312 , so that the luminance of the second light source  312  is gradually changed, and the abrupt change of the backlight brightness of the backlight source during the switch between the sharing mode phase (namely, a sharing state) and the privacy mode phase (namely, a peep-proof state) is avoided, and thus the fatigue of the human eyes is improved. 
     In an embodiment, referring to  FIG. 20 , in the transition phase during which the sharing mode phase is switched to the privacy mode phase, a voltage signal with gradually decreasing duty cycles is provided for the second light source  312 . In the sharing mode phase, a drive voltage is provided for the second light source  312  and a duty cycle is 100%. In the transition phase, a voltage signal with gradually decreasing duty cycles is provided for the second light source  312 . For example, a voltage signal with a duty cycle of 80%, 60%, 40%, and 20% in sequence is provided. In the privacy mode phase, no drive voltage is provided for the second light source  312  and a duty cycle is 0%. Therefore, during the change from the sharing mode phase to the transition phase and then from the transition phase to the privacy mode phase, duty cycles of signals provided for the second electrode  12  gradually decrease, and the luminance of the second light source  312  gradually decreases, so that the abrupt change of the backlight brightness of the backlight source is avoided, and thus the fatigue of the human eyes is improved. 
       FIG. 21  is a timing diagram of another backlight source according to an embodiment of the present disclosure. With reference to  FIG. 21 , in the transition phase during which the privacy mode phase is switched to the sharing mode phase, a voltage signal with gradually increasing duty cycles is provided for the second light source  312 . In the privacy mode phase, no drive voltage is provided for the second light source  312  and a duty cycle is 0%. In the transition phase, a voltage signal with gradually increasing duty cycles is provided for the second light source  312 . For example, a voltage signal with a duty cycle of 20%, 40%, 60%, and 80% in sequence is provided. In the sharing mode phase, a drive voltage with a duty cycle of 100% is provided for the second light source  312 . Therefore, during the change from the privacy mode phase to the transition phase and then from the transition phase to the sharing mode phase, duty cycles of signals provided for the second electrode  12  gradually increase, and the luminance of the second light source  312  gradually increases, so that the abrupt change of the backlight brightness of the backlight source is avoided, and thus the fatigue of the human eyes is improved. 
       FIG. 22  is a timing diagram of another backlight source according to an embodiment of the present disclosure. With reference to  FIGS. 18, 19, and 22 , the first light source  311  is turned off in the sharing mode phase. In the transition phase, a voltage signal with gradually changing duty cycles is provided for the first light source  311 . In the embodiments of the present disclosure, during the change from the sharing mode phase to the privacy mode phase, the first light source  311  is changed from off to on. During the change from the privacy mode phase to the sharing mode phase, the first light source  311  changes from on to off. In the transition phase, a voltage signal with gradually changing duty cycles is provided for the first light source  311 , so that the luminance of the first light source  311  is gradually changed, the abrupt change of the backlight brightness of the backlight source during the switch between the sharing mode phase (namely, a sharing state) and the privacy mode phase (namely, a peep-proof state) is avoided, and thus the fatigue of the human eyes is improved. 
     In an embodiment, referring to  FIG. 22 , in the transition phase during which the sharing mode phase is switched to the privacy mode phase, a voltage signal with gradually increasing duty cycles is provided for the first light source  311 . In the sharing mode phase, no drive voltage is provided for the first light source  311  and a duty cycle is 0%. In the transition phase, a voltage signal with gradually increasing duty cycles is provided for the first light source  311 . For example, a voltage signal with a duty cycle of 20%, 40%, 60%, and 80% in sequence is provided. In the privacy mode phase, a drive voltage with a duty cycle of 100% is provided for the first light source  311 . Therefore, during the change from the sharing mode phase to the transition phase and then from the transition phase to the privacy mode phase, duty cycles of signals provided for the first light source  311  gradually increase, and the luminance of the first light source  311  gradually increases, so that the abrupt change of the backlight brightness of the backlight source is avoided, and thus the fatigue of the human eyes is improved. 
       FIG. 23  is a timing diagram of another backlight source according to an embodiment of the present disclosure. With reference to  FIG. 23 , in the transition phase during which the privacy mode phase is switched to the sharing mode phase, a voltage signal with gradually decreasing duty cycles is provided for the first light source  311 . In the privacy mode phase, a drive voltage with a duty cycle of 100% is provided for the first light source  311 . In the transition phase, a voltage signal with gradually decreasing duty cycles is provided for the first light source  311 . For example, a voltage signal with a duty cycle of 80%, 60%, 40%, and 20% in sequence is provided. In the sharing mode phase, no drive voltage is provided for the first light source  311  and a duty cycle is 0%. Therefore, during the change from the privacy mode phase to the transition phase and then from the transition phase to the sharing mode phase, duty cycles of signals provided for the first light source  311  gradually decrease, and the luminance of the first light source  311  gradually decreases, so that the abrupt change of the backlight brightness of the backlight source is avoided, and thus the fatigue of the human eyes is improved. 
     In an implementation, the first light source  311  is always on in the sharing mode phase, the transition phase and the privacy mode phase. 
     Exemplarily, referring to  FIGS. 18 and 19 , the backlight source  300  includes a first light guide plate  321  and a second light guide plate  322 . The first light source  311  is disposed on a light incidence side of the first light guide plate  321 , the second light source  312  is disposed on a light incidence side of the second light guide plate  322 , and the second light guide plate  322  is disposed on a light-emitting side of the first light guide plate  321 . In the sharing mode phase, the second light source  312  is turned on, and the light emitted by the second light source  312  enters the second light guide plate  322  and is emitted through the light-emitting side of the second light guide plate  322  to serve as the backlight. In the privacy mode phase, the first light source  311  is turned on, the second light source  312  is turned off, and the light emitted by the first light source  311  enters the first light guide plate  321 , is emitted into the second light guide plate  322  through the light-emitting side of the first light guide plate  321 , and is emitted through the light-emitting side of the second light guide plate  322  to serve as the backlight. In other implementations, the backlight source includes one light guide plate, and the light emitted by the first light source  311  and the second light source  312  may also enter a same light guide plate. 
     Exemplarily, referring to  FIGS. 18 and 19 , the light incidence side of the first light guide plate  321  is adjacent to the light-emitting side of the first light guide plate  321 , the light incidence side of the second light guide plate  322  is adjacent to the light-emitting side of the second light guide plate  322 , and the backlight source  300  is an edge backlight source. In other implementations, the backlight source  300  may also be a direct backlight source. 
       FIG. 24  is a top view of another backlight source according to an embodiment of the present disclosure. In conjunction with  FIGS. 9 and 24 , the view angle control panel  100  includes a voltage gradient conversion circuit, and the voltage gradient conversion circuit is configured to provide a voltage signal with a reduced gradient for multiple sub-electrodes  121  arranged in a first direction. In the first direction, the rotation angle of the liquid crystal molecule  211  gradually decreases, and the luminance of the view angle control panel  100  is gradually enhanced. The first light source  311  includes multiple first lamp beads  3111 , and a distance between adjacent first lamp beads  3111  gradually increases in the first direction. That is, in the first direction, the backlight brightness provided by the first light source  311  gradually decreases to match a trend that the luminance of the view angle control panel  100  gradually increases, so that, in the privacy mode phase, the brightness of a picture displayed by the display device is uniform in each region. 
     Exemplarily, referring to  FIG. 24 , the second light source  312  includes multiple second beads  3121 . In the first direction, the second lamp beads  3121  are arranged at equal intervals. Namely, every two adjacent second lamp beads  3121  have a same interval, so that the brightness of a picture displayed by the display device is uniform in each region in the sharing mode phase. 
     In an embodiment, with continued reference to  FIG. 19 , a surface of a side of the second light guide plate  322  away from the first light guide plate  321  is etched to form multiple microstructures  3221 . A relative position of the microstructure  3221  and the first light source  311  is different from a relative position of the microstructure  3221  and the second light source  312 . Based on refraction and/or reflection action, the microstructure  3221  is configured to shrink light lays casted by the first light source  311  on the microstructure  3221  and diffuse light lays casted by the second light source  312  on the microstructure  3221 . 
       FIG. 25  is a cross-sectional view of another backlight source according to an embodiment of the present disclosure. With reference to  FIG. 25 , the backlight source  300  further includes a third light guide plate  323 , both the first light source  311  and the second light source  312  are disposed on the light incidence side of the third light guide plate  323 , and the light incidence side of the third light guide plate  323  is opposite to a light-emitting side of the third light guide plate  323 . An embodiment of the present disclosure provides a direct backlight source, and the second light source  312  is turned on in the sharing mode phase. In the privacy mode phase, the first light source  311  is turned on and the second light source  312  is turned off. In the transition phase, a voltage signal with gradually changing duty cycles is provided for the second light source  312 . 
       FIG. 26  is a schematic diagram of an automobile according to an embodiment of the present disclosure. With reference to  FIG. 26 , the automobile includes the display device  500  in the above embodiments, and in some implementations, the display device  500  may include the backlight source  300  in the above embodiments. Thus, the abrupt change of the display brightness of the display device  500  during the switch between the sharing mode phase and the privacy mode phase is avoided, and thus the fatigue of the human eyes is improved. 
     Exemplarily, referring to  FIG. 26 , the automobile further includes a co-pilot seat and a windshield  600 , and the display device  500  is disposed between the co-pilot seat and the windshield  600 . The display device  500  provided in the embodiments of the present disclosure is applied to a vehicle-mounted display. When a co-driver watches some entertainment videos, in order to prevent the influence on a main driver to drive the automobile, it is necessary to make a picture of the display device  500  at a first side view angle (such as a left side view angle) cannot be viewed by the main driver, and a picture at a second side view angle (such as a right side view angle) can be viewed by the co-driver. 
     It should be noted that the above are merely preferred embodiments of the present disclosure and the technical principles applied herein. It should be understood by those skilled in the art that the present disclosure is not limited to the particular embodiments described herein. For those skilled in the art, various apparent modifications, adaptations, combinations and substitutions may be made without departing from the scope of the present disclosure. Therefore, although the present disclosure has been described in detail through the above embodiments, the present disclosure is not limited to the above embodiments and may include more other equivalent embodiments without departing from the concept of the present disclosure. The scope of the present disclosure is determined by the scope of the appended claims.