A display screen, an electronic device, and a method for manufacturing a display screen

Abstract

The application provides a display screen, an electronic device and a preparation method of the display screen. The display screen comprises a cover plate, a touch panel and a liquid crystal layer, and the liquid crystal layer is arranged between the cover plate and the touch panel. The touch panel comprises a plurality of signal emitting lines and a plurality of signal receiving lines, and the plurality of signal emitting lines and the plurality of signal receiving lines are arranged in different layer structures respectively. The intersection position between the projection of the signal emitting line and the projection of the signal receiving line forms a fingerprint sensing point. The liquid crystal layer comprises a plurality of first regions and a second region between any two adjacent first regions. The plurality of first regions are arranged one by one corresponding to the plurality of fingerprint sensing points, and the projection of the first region on the touch panel covers the fingerprint sensing point arranged corresponding thereto. In addition, the relative dielectric constant of the first region is greater than that of the second region, so that the induced voltage signal at the fingerprint sensing point is increased, thereby being beneficial to realizing the fingerprint identification of the display screen.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of display, in particular to a display screen, an electronic device and a preparation method of the display screen. BACKGROUND

[0002] Fingerprint recognition technology is increasingly applied in electronic devices (mobile phones, tablet computers or smart watches and other wearable devices), which is crucial to the personal information security of users.

[0003] At present, the fingerprint recognition technology mainly includes capacitive, optical and ultrasonic. Among them, optical fingerprint recognition is generally applied in organic light emitting diode (OLED) display screen, which can realize fingerprint recognition by the self-luminous characteristics of OLED. However, since OLED display screen needs to light up the specific area of the display screen when realizing fingerprint recognition, it is inevitable to cause the problem that the pixels of the fingerprint recognition area are prone to aging, and the power consumption is also increased. The ultrasonic fingerprint recognition technology is not mature, and the cost is high, which is difficult to be commercialized in a short time. The capacitive fingerprint recognition has low cost and mature technology, so the capacitive fingerprint recognition technology is currently used in electronic devices to realize the fingerprint recognition function.

[0004] With the increasing requirement of users on the functional integration of electronic devices, the person skilled in the art thinks to integrate the fingerprint recognition function with the existing functions of the electronic device. Since the technology of capacitive touch display screen is relatively mature, and the operation process of fingerprint recognition and touch is similar. Therefore, integrating the fingerprint recognition function with the touch function has become an important direction for future development in the field. SUMMARY

[0005] The present application provides a display screen, an electronic device and a preparation method of the display screen, to improve the fingerprint recognition depth of the display screen and improve the accuracy of fingerprint recognition.

[0006] In a first aspect, the present application provides a display screen, which comprises a cover plate, a touch panel and a liquid crystal layer, the liquid crystal layer being arranged between the cover plate and the touch panel. The touch panel comprises a first layer structure, a second layer structure, a plurality of signal emitting lines and a plurality of signal receiving lines, the plurality of signal emitting lines being arranged on the first layer structure, the plurality of signal receiving lines being arranged on the second layer structure, the plurality of signal emitting lines being arranged in parallel and extending along a first direction, the plurality of signal receiving lines being arranged in parallel and extending along a second direction, the first direction being different from the second direction. In this way, along a stacking direction from the first layer structure to the second layer structure, a plurality of intersection positions are formed between the projection of the plurality of signal emitting lines and the projection of the plurality of signal receiving lines, and the plurality of intersection positions can be used as a plurality of fingerprint sensing points. When the liquid crystal layer is arranged, the liquid crystal layer comprises a plurality of first regions and a second region between any two adjacent first regions, the plurality of first regions being arranged one-to-one corresponding to the plurality of fingerprint sensing points, and the projection of the first region on the touch panel covers the fingerprint sensing point arranged corresponding thereto, and the relative dielectric constant of the first region is greater than that of the second region.

[0007] The display screen provided by the embodiments of the present application has a liquid crystal layer arranged between the touch panel and the cover plate. Since the relative dielectric constant of the first region in the liquid crystal layer is greater than that of the second region, and the first region is arranged opposite to the fingerprint sensing point of the touch panel, the sensing signal at the fingerprint sensing point can be increased, and the sensing signals of other fingerprint sensing points around the fingerprint sensing point can continuously attenuate with the increase of the distance from the ridge of the fingerprint, so that the steepness of the curve of the signal distribution caused by each fingerprint can be increased. When all the sensing signals are superimposed, the curve fluctuates, so that the relative position of the ridge and the valley of the fingerprint can be determined, the shape of the fingerprint can be distinguished, and the purpose of fingerprint recognition can be achieved.

[0008] It can be understood that the greater the difference between the relative dielectric constants of the liquid crystal molecules of the first region and the second region, the better the fingerprint recognition effect that can be achieved when they are used in the touch panel. In a possible implementation manner of the present application, the relative dielectric constant of the liquid crystal molecules of the first region can be greater than or equal to 15 and less than or equal to 100, and the relative dielectric constant of the liquid crystal molecules of the second region can be greater than or equal to 2 and less than 15.

[0009] There are many ways to realize the differential design of the relative permittivity of the first region and the second region of the liquid crystal layer. In one possible implementation of the present application, the relative permittivity of the first region and the second region can be adjusted by adjusting the pre-tilt angle of the liquid crystal molecules in the first region and the second region, respectively. It can be understood that when the liquid crystal molecules are negative liquid crystal molecules, the greater the pre-tilt angle of the liquid crystal molecules, the greater the relative permittivity. At this time, the pre-tilt angle of the liquid crystal molecules in the first region of the liquid crystal layer can be greater than the pre-tilt angle of the liquid crystal molecules in the second region. For example, the pre-tilt angle of the liquid crystal molecules in the first region of the liquid crystal layer can be greater than or equal to 45° and less than or equal to 90°, and the pre-tilt angle of the liquid crystal molecules 601 in the second region can be greater than or equal to 0° and less than 45°, thereby realizing the differential design of the relative permittivity of the first region and the second region.

[0010] Similarly, when the liquid crystal molecules are positive liquid crystal molecules, the smaller the pre-tilt angle of the liquid crystal molecules, the greater the relative permittivity. At this time, the pre-tilt angle of the liquid crystal molecules in the first region of the liquid crystal layer can be less than the pre-tilt angle of the liquid crystal molecules in the second region. For example, the pre-tilt angle of the liquid crystal molecules in the first region of the liquid crystal layer can be greater than or equal to 0° and less than or equal to 45°, and the pre-tilt angle of the liquid crystal molecules in the second region can be greater than 45° and less than or equal to 90°, thereby realizing the differential design of the relative permittivity of the first region and the second region.

[0011] In one possible implementation of the present application, in order to effectively cover the corresponding fingerprint sensing point on the touch panel, the area of the first region can be adjusted. For example, the area of the first region of the liquid crystal layer can be greater than or equal to 10 μm × 10 μm. In addition, the area of the first region can be adjusted according to the spacing between two adjacent first regions. For example, when the spacing between two adjacent fingerprint sensing points is 50 μm, the area of the first region of the liquid crystal layer can be greater than or equal to 25 μm × 25 μm and less than or equal to 40 μm × 40 μm.

[0012] In one possible implementation of the present application, a polarizing plate can also be provided in the display screen, and the polarizing plate is arranged between the liquid crystal layer and the touch panel. In order to reduce the modulation effect of the liquid crystal layer on the outgoing light after passing through the polarizing plate, the azimuth angle direction of the liquid crystal molecules in the liquid crystal layer can be perpendicular to the transmission axis direction of the polarizing plate, that is, the long axis direction of the projection of the liquid crystal molecules in the liquid crystal layer on the touch panel is perpendicular to the direction of the polarization transmission axis of the polarizing plate.

[0013] In a second aspect, the application further provides an electronic device, comprising a back shell, a middle frame, and the display screen of the first aspect, wherein the display screen and the back shell are arranged on two sides of the middle frame and are fixedly connected with the middle frame. In specific implementation, the electronic device can be a display, a television, a mobile phone, a notebook computer, a smart watch, etc.

[0014] The display screen of the electronic device of the application is provided with a liquid crystal layer between the touch panel and the cover plate. Due to the relative dielectric constant of the first region of the liquid crystal layer being greater than the relative dielectric constant of the second region, and the fingerprint sensing point of the touch panel being arranged opposite to the first region, the sensing signal at the fingerprint recognition point can be increased, while the sensing signals of other fingerprint sensing points around the fingerprint recognition point continue to attenuate with the increasing distance from the ridge of the fingerprint, so that the steepness of the curve of the signal distribution caused by each fingerprint can be increased. When all the sensing signals are superimposed, the curve fluctuates, so that the relative position of the ridge and the valley of the fingerprint is determined, the fingerprint shape is distinguished, and the purpose of fingerprint recognition is achieved.

[0015] In addition, since the liquid crystal layer does not need to be driven by a circuit, and the liquid crystal layer itself has no absorption effect on light, the influence of the liquid crystal layer arranged in the display screen on the power consumption of the display screen is small.

[0016] In a third aspect, the application further provides a preparation method of the display screen, comprising:

[0017] The substrate for making the liquid crystal layer is divided into a plurality of first regions and a second region between any two adjacent first regions, an alignment layer is formed in the first region and the second region respectively, and the alignment of the alignment layer in the first region is different from that of the alignment layer in the second region;

[0018] The liquid crystal material is coated on the alignment layer in the first region and the alignment layer in the second region respectively;

[0019] The liquid crystal material is solidified into a film material, and the substrate is peeled off to obtain the liquid crystal layer. The relative dielectric constant of the liquid crystal molecules in the first region of the liquid crystal layer is greater than the relative dielectric constant of the liquid crystal molecules in the second region of the liquid crystal layer.

[0020] Through the patterned alignment layer, the pretilt angle difference of the liquid crystal molecules in the first region and the second region can be realized, so that the regional difference of the relative dielectric constant is obtained.

[0021] In a possible implementation of the present application, the display screen further comprises a touch panel and a cover plate, and after the liquid crystal layer is obtained, the preparation method further comprises: bonding the liquid crystal layer between the polarizer and the cover plate, and making the long axis direction of the projection of the liquid crystal molecules in the liquid crystal layer on the polarizer perpendicular to the direction of the polarization transmission axis of the polarizer. Thus, the modulation effect of the liquid crystal layer on the outgoing light after passing through the polarizer can be reduced. In addition, the liquid crystal layer itself has no absorption effect on light, and the influence of the liquid crystal layer on the power consumption of the display screen is small.

[0022] In a possible implementation of the present application, the display screen further comprises a touch panel, the touch panel comprises a first layer structure, a second layer structure, a plurality of signal emitting lines and a plurality of signal receiving lines, the plurality of signal emitting lines are arranged on the first layer structure, and the plurality of signal receiving lines are arranged on the second layer structure; along the stacking direction from the first layer structure to the second layer structure, a plurality of intersection positions between the projection of the plurality of signal emitting lines and the projection of the plurality of signal receiving lines are used as a plurality of fingerprint sensing points.

[0023] In this way, after the liquid crystal layer is bonded between the polarizer and the cover plate, the preparation method further comprises: bonding the side of the polarizer away from the liquid crystal layer to the touch panel; and making the projection of the first region of the liquid crystal layer on the touch panel cover the fingerprint sensing points of the touch panel.

[0024] The display screen obtained by using the preparation method of the display screen provided in the embodiments of the present application is provided with a liquid crystal layer between the touch panel and the cover plate. Because the relative dielectric constant of the first region of the liquid crystal layer is greater than the relative dielectric constant of the second region, and the first region is arranged opposite to the fingerprint sensing points of the touch panel, the induced voltage signal at the fingerprint sensing point can be increased, and the induced signals of other fingerprint sensing points around the fingerprint sensing point continue to attenuate with the increase of the distance from the ridge of the fingerprint, so that the steepness of the signal distribution curve caused by each fingerprint can be increased. When all the induced signals are superimposed, the fluctuation of the curve occurs, so that the relative position of the ridge and the valley of the fingerprint can be determined, the shape of the fingerprint can be distinguished, and the purpose of fingerprint recognition can be achieved. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 The structural diagram of the touch panel provided in an embodiment of the present application is shown;

[0026] Figure 2 The structural diagram of the touch panel provided in another embodiment of the present application is shown;

[0027] Figure 3 The structural diagram of the display screen provided in an embodiment of the present application is shown;

[0028] Figure 4 The enlarged diagram of the partial structure of the touch panel provided in an embodiment of the present application is shown.

[0029] Figure 5 A schematic diagram of a fingerprint identification principle provided by an embodiment of the present application;

[0030] Figure 6 A schematic diagram of a fingerprint identification principle provided by another embodiment of the present application;

[0031] Figure 7 A schematic diagram of liquid crystal anisotropy provided by an embodiment of the present application;

[0032] Figure 8 A schematic diagram of a structure of a display screen provided by another embodiment of the present application;

[0033] Figure 9 A top view of a display screen provided by an embodiment of the present application;

[0034] Figure 10 A schematic diagram of liquid crystal molecule position information provided by an embodiment of the present application;

[0035] Figure 11 A schematic diagram of a structure of a display screen provided by another embodiment of the present application;

[0036] Figures 12a to 12c A schematic diagram of a preparation method of a display screen provided by an embodiment of the present application;

[0037] Figure 13 A schematic diagram of a preparation method of a display screen provided by another embodiment of the present application;

[0038] Figure 14 A schematic diagram of a structure of an electronic device provided by an embodiment of the present application.

[0039] Reference signs:

[0040] 1-touch panel; 101-signal emitting line; 102-signal receiving line; 103-fingerprint sensing point; 2-fingerprint; 201-ridge;

[0041] 202-valley; 3-display panel; 4-polarizer; 5-cover plate; 6-liquid crystal layer; 601-liquid crystal molecule; 602-first region;

[0042] 603-second region; 7-encapsulation layer; 8-substrate; 801a, 801b-alignment layer; 802a-first electrode; 802b-second electrode.

[0043] 9-touch area. DETAILED DESCRIPTION

[0044] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the drawings.

[0045] In order to facilitate the understanding of the display screen provided by the embodiments of the present application, the application scenario thereof will be introduced first.

[0046] At present, with the wide application of fingerprint recognition technology in the field of electronic devices, various electronic devices can realize screen unlocking, fast payment, file encryption and other functions based on this technology, greatly improving the security of users' personal information and enhancing the user experience.

[0047] The traditional electronic device with fingerprint recognition usually sets a fingerprint recognition area on the side where the display screen is located. With the development of full-screen, the fingerprint recognition area gradually moves from the side where the display screen of the electronic device is located to the back or the side of the electronic device. Whether the fingerprint recognition area is set on the side where the display screen is located or on the back cover or the middle frame of the electronic device, a separate fingerprint recognition module needs to be set in the electronic device by inlaying. However, the internal space of the electronic device is limited. In order to meet the increasing functional requirements of users on electronic devices, and without changing the internal space of the electronic device, some functional modules in the electronic device need to be integrated.

[0048] When integrating the functional modules in the electronic device, the functional implementation of each functional module to be integrated will be considered first. At present, the fingerprint recognition technology mainly includes capacitive, optical and ultrasonic types. Among them, optical fingerprint recognition is generally applied in organic light emitting diode (OLED) display screens, which can realize fingerprint recognition by means of the self-luminous characteristics of OLED. However, since the OLED display screen needs to light up a specific area of the display screen when implementing fingerprint recognition, it is inevitable that the pixels in the fingerprint recognition area will be prone to aging, and the power consumption will also increase. The existing technology of ultrasonic fingerprint recognition is not mature, and the cost is high, so it is difficult to be commercialized in a short time. The cost of capacitive fingerprint recognition is low, and the technology is mature, so capacitive fingerprint recognition technology is currently used in electronic devices to realize fingerprint recognition function.

[0049] Since the technology of capacitive touch display screen is relatively mature, and the operation process of fingerprint recognition is similar to that of touch, integrating the fingerprint recognition function and the touch function of the display screen will be the main development direction of the multifunctional integration of future electronic devices, so as to realize under-screen fingerprint recognition of the electronic device.

[0050] At present, the integration of fingerprint recognition and touch function is mainly realized through the touch panel of the display screen. Referring to Figure 1 , Figure 1Fig. 1 is a schematic diagram of a touch panel according to an embodiment of the present application. The touch panel 1 includes a plurality of signal transmitting lines 101 and a plurality of signal receiving lines 102. The plurality of signal transmitting lines 101 extend in a first direction, and the plurality of signal receiving lines 102 extend in a second direction. The first direction is different from the second direction.

[0051] Referring to Figure 1 and Figure 2 , Figure 2 Fig. 2 is a schematic diagram of a cross-sectional structure of the touch panel. The touch panel includes a first layer structure (not shown) and a second layer structure (not shown). The plurality of signal transmitting lines 101 are disposed on the first layer structure, and the plurality of signal receiving lines 102 are disposed on the second layer structure. The plurality of signal transmitting lines 101 and the plurality of signal receiving lines 102 are disposed in a direction of stacking from the first layer structure to the second layer structure. The plurality of signal transmitting lines 101 and the plurality of signal receiving lines 102 form a plurality of intersection positions in the direction of stacking from the first layer structure to the second layer structure. In one possible embodiment, the plurality of signal transmitting lines 101 and the plurality of signal receiving lines 102 can be disposed perpendicularly. It can be understood that the plurality of intersection positions can be used as a plurality of capacitive nodes of the touch panel, and the capacitive nodes can be used as a plurality of fingerprint sensing points 103.

[0052] In detail, referring to Figure 1 and Figure 2 , each of the fingerprint sensing points 103 can be used as an integration circuit. A specific electric field is formed between the signal transmitting line 101 and the signal receiving line 102 at the fingerprint sensing point 103, so that electric charges are accumulated to generate an induced voltage, which is output as an analog signal. When a finger is not close to the fingerprint sensing point 103, the voltage generated at each of the fingerprint sensing points 103 is substantially consistent. When the finger is close to the fingerprint sensing point 103, a capacitance Cp is formed between a peak 201 of a fingerprint 2 of the finger and the fingerprint sensing point 103, and a capacitance Cv is formed between a valley 202 of the fingerprint 2 of the finger and the fingerprint sensing point. Because the distance between the peak 201 of the fingerprint 2 of the finger and the signal receiving line 102 is different from the distance between the valley 202 of the fingerprint 2 of the finger and the signal receiving line 102, and the distance between the peak 201 of the fingerprint 2 of the finger and the signal receiving line 102 is smaller than the distance between the valley 202 of the fingerprint 2 of the finger and the signal receiving line 102, the capacitance Cp is greater than the capacitance Cv. Because a greater capacitance indicates a greater amount of accumulated electric charges, and thus a greater induced voltage, the voltage Vp generated between the peak 201 of the fingerprint 2 of the finger and the fingerprint sensing point 103 is greater than the voltage Vv generated between the valley 202 of the fingerprint 2 of the finger and the fingerprint sensing point 103. Thus, different voltage value distributions are obtained on the plurality of fingerprint sensing points 103, which are read by the signal receiving line 102 and converted into digital signals by an analog-to-digital converter, so that the fingerprint information is obtained.

[0053] Reference Figure 3 , Figure 3 This is a schematic diagram of the layer structure of a conventional display screen. The display screen may include a display panel 3, a touch panel 1, a polarizer 4, and a cover plate 5. The touch panel 1 is disposed between the display panel 3 and the polarizer 4, and the cover plate 5 is disposed on the side of the polarizer 4 away from the touch panel 1.

[0054] Refer to together Figure 3 and Figure 4 , Figure 4 This is a magnified view of a portion of the display screen structure. When a finger touches the cover plate 5, the ridge 201 of the fingerprint will generate an induced voltage signal with the fingerprint sensing point 103 in different areas. The magnitude of the induced voltage signal decreases as the distance between the fingerprint sensing point 103 and the ridge 201 of the fingerprint 2 increases. The induced voltage signal is the largest at the fingerprint sensing point 103 directly opposite the ridge 201 of the fingerprint 2.

[0055] Can be referred to together Figure 4 and Figure 5 , Figure 5 The diagram illustrates the sensing signal curves generated between the ridges 201 of the three fingerprint lines 2 and multiple fingerprint sensing points 103. Among them, Figure 5 The horizontal axis represents each fingerprint sensing point 103, and the vertical axis represents the value of the induced capacitance signal generated between the ridge 201 of fingerprint 2 and the fingerprint sensing point 103. In this application, the unit of the induced capacitance signal value is not specifically limited; it can be any unit. Figure 5 In the diagram, each solid line represents the sensing signal curve between a ridge 201 of fingerprint 2 and each fingerprint sensing point 103, and the peak position represents the sensing signal at the fingerprint sensing point 103 closest to the ridge 201. Figure 5 It can be seen that the curve of the sensing signal distribution caused by each fingerprint 2 has a relatively small steepness.

[0056] Under normal circumstances, you can refer to Figure 3 The thickness of polarizer 4 is tens of micrometers, and the thickness of cover plate 5 is several hundred micrometers. (See also...) Figure 3 , Figure 4 and Figure 5 When the thickness D of the cover plate 5 is large, the curve of the composite signal obtained by superimposing all the sensing signals at each fingerprint sensing point 103 can be used. Figure 5 The dotted line in the diagram indicates that the curve of the superimposed signal tends to be flat, making it impossible to distinguish the location of the ridge 201 of fingerprint 2, and the shape and outline of fingerprint 2 cannot be presented, thus failing to achieve the effect of fingerprint recognition.

[0057] When the thickness of the cover plate 5 decreases, the steepness of the sensing signal curve corresponding to different fingerprint sensing points 103 for each fingerprint ridge 201 will increase, such as...Figure 6 In this case, the curve of the integrated signal obtained after the induction signals at each fingerprint sensing point 103 are superimposed (dashed line in FIG. 10) will thus have more obvious fluctuation changes, thereby facilitating extraction of the relative position information of the ridge 201 of the fingerprint 2, and the contour of the fingerprint 2 can be reproduced, thereby achieving the effect of fingerprint recognition. Figure 6

[0058] However, the current technology of capacitive under-screen fingerprint recognition can only achieve a recognition penetration depth of about 300 μm, which means that the thickness of the cover plate 5 (see FIG. 1) needs to be very small. Figure 3 However, if the thickness of the cover plate 5 is too small, the structural strength of the entire display screen will be poor, which can easily cause damage to the display screen.

[0059] Based on this, the display screen provided in the present application can improve the fingerprint recognition effect of the display screen.

[0060] The display screen provided in the embodiments of the present application can be applied in, but is not limited to, display devices, mobile phones, notebook computers, smart watches and other electronic devices, for displaying text, pictures and other information, or responding to the touch, sliding and other operations of a user, to achieve the purpose of human-computer interaction. In addition, it can be understood that the display screen of the present application can be a flexible display screen, for use in foldable electronic devices, or can also be a rigid display screen, for use in non-foldable electronic devices such as straight phones, which are not specifically limited in the present application. In order to make the purpose, technical solutions and advantages of the present application clearer, the present application will be described in further detail below in combination with the drawings and specific embodiments.

[0061] The relative permittivity is a physical parameter representing the dielectric or polarization properties of a dielectric material. Its value is equal to the ratio of the capacitance of a capacitor made of the same size of the predicted material as the dielectric to that made of vacuum as the dielectric, and this value is also a representation of the electric storage capacity of the material. The greater the relative permittivity of the dielectric material, the stronger the electric storage capacity of the capacitor made of the same size of the material.

[0062] Therefore, if the relative permittivity of the medium between the ridge of the fingerprint and the fingerprint sensing point is increased, the difference in the intensity of the induction signals generated between the ridge and the valley of the fingerprint and the fingerprint sensing point can be increased, thereby distinguishing the relative positions of the ridge 201 and the valley 202 of the fingerprint 2, and further improving the fingerprint recognition effect.

[0063] Liquid crystals are a kind of phase state, and have a certain spatial order. Common liquid crystal molecules 601 are rod-shaped structures, which can be referred to as Figure 7 ​Since the liquid crystal molecules 601 have anisotropy, that is, the refractive index and the relative dielectric constant along the long axis direction (the direction indicated by the x axis) and the short axis direction (the direction indicated by the y axis) are different. By aligning the liquid crystal molecules 601 (selecting the long axis or the short axis direction), the relative dielectric constant can be selected. Therefore, in this application, the anisotropy of the liquid crystal molecules 601 can be used to align the liquid crystal molecules to increase the relative dielectric constant between the ridges of the fingerprint and the fingerprint sensing points.

[0064] Generally, we call the liquid crystal molecules with the relative dielectric constant of the long axis direction greater than that of the short axis direction as positive liquid crystal molecules, and the liquid crystal molecules with the relative dielectric constant of the short axis direction greater than that of the long axis direction as negative liquid crystal molecules. Since the working principle of positive liquid crystal molecules and negative liquid crystal molecules is the same when used as a medium, in the following embodiments of this application, positive liquid crystal molecules are taken as an example for illustration.

[0065] In addition, the alignment of liquid crystal molecules generally needs to rely on an alignment layer. There is an intermolecular force between the liquid crystal molecules close to the alignment layer and the molecules of the alignment layer. The liquid crystal molecules will arrange along the orientation direction of the molecules of the alignment layer, and other liquid crystal molecules far from the alignment layer will follow the liquid crystal molecules close to the alignment layer to orient through long-range forces (intermolecular forces between liquid crystal molecules).

[0066] On this basis, as shown in Figure 8 , Figure 8 is a structural schematic diagram of a display screen provided by an embodiment of the present application. In this embodiment, the display screen can include a cover plate 5, a touch panel 1, and a liquid crystal layer 6, wherein the liquid crystal layer 6 is arranged between the touch panel 1 and the cover plate 5. The thickness of the liquid crystal layer 6 can be, but is not limited to, greater than or equal to 5 μm and less than or equal to 50 μm, and can be, for example, 8 μm, 15 μm, 20 μm, 28 μm, etc. In the specific arrangement of the touch panel 1, the embodiments shown in Figure 1 and Figure 2 can be referred to for arrangement, which will not be described here.

[0067] Referring to Figure 8 and Figure 9 , Figure 9 is a top view of a display screen provided by an embodiment of the present application. In the specific arrangement of the liquid crystal layer 6, the liquid crystal layer 6 includes a plurality of first regions 602 and a second region 603 between any two adjacent first regions 602. The relative dielectric constant of the first region 602 is greater than that of the second region 603.

[0068] In the arrangement of the liquid crystal layer 6 in the touch panel 1, continue to refer to Figure 8 and Figure 9The first area 602 of the liquid crystal layer 6 can be arranged one-to-one corresponding to the fingerprint sensing points 103 of the touch panel 1, and the projection of the first area 602 on the touch panel 1 covers the fingerprint sensing point 103 corresponding to the first area 602.

[0069] In the embodiments of the present application, reference is made to Figure 9 The area of the first area 602 of the liquid crystal layer 6 is not specifically limited, and can be adjusted according to the interval between two adjacent fingerprint sensing points 103. In some possible embodiments of the present application, the area of the first area 602 of the liquid crystal layer 6 can be greater than or equal to 10 μm x 10 μm, so that the projection of the first area 602 on the touch panel 1 can effectively cover the fingerprint sensing point 103 corresponding thereto. For example, when the interval between two adjacent fingerprint sensing points is 50 μm, the area of the first area 602 of the liquid crystal layer 6 can be greater than or equal to 25 μm x 25 μm and less than or equal to 40 μm x 40 μm. In addition, it can be understood that in the embodiments of the present application, the center of the fingerprint sensing point 103 and the first area 602 do not need to coincide, as long as the projection of the first area 602 on the touch panel covers the fingerprint sensing point 103, so as to increase the relative dielectric constant between the cover plate 5 (see Figure 8 ) and the fingerprint sensing point 103.

[0070] Continuing to refer to Figure 9 Since the liquid crystal layer 6 has a large relative dielectric constant ε1 at the position (the first area 602) corresponding to the fingerprint sensing point 103 of the touch panel, and has a small relative dielectric constant ε2 at the area (the second area 603) outside the fingerprint sensing point 103, when the finger contacts the display screen, the coupling capacitance value formed by the ridge of the fingerprint and the fingerprint sensing point 103 directly below the ridge is large. In addition, since the relative dielectric constant of the first area 602 of the liquid crystal layer 6 opposite to the fingerprint sensing point 103 is greater than the relative dielectric constant of the second area 603 around the fingerprint sensing point 103, the first area 602 can integrate the electromagnetic field lines, so as to guide the electromagnetic field lines to gather at the fingerprint sensing point 103, so that the induced voltage signal at the fingerprint sensing point 103 increases, and the induced signal of the other fingerprint sensing points 103 around the fingerprint sensing point 103 continuously attenuates with the increase of the distance from the ridge of the fingerprint. Therefore, the steepness of the curve of the induced signal distribution caused by each fingerprint increases, and after all the induced signals are superimposed, the curve fluctuates, so that the relative position of the ridge and the valley of the fingerprint is determined, the shape of the fingerprint is distinguished, and the purpose of fingerprint recognition is achieved.

[0071] In some embodiments of the present application, the liquid crystal molecules in the liquid crystal layer can be positive liquid crystal molecules or negative liquid crystal molecules. In either case, the relative dielectric constant of the two regions can be adjusted by adjusting the relative dielectric constant of the liquid crystal molecules in the first region and the second region. For example, continuing to refer to Figure 9 The relative dielectric constant of the liquid crystal molecules in the first region 602 can be greater than or equal to 15 and less than or equal to 100, and the relative dielectric constant of the liquid crystal molecules in the second region 603 can be greater than or equal to 2 and less than 15. It should be understood that the relative dielectric constant of the liquid crystal molecules in the first region 602 and the second region 603 is not limited to this range, and the greater the difference between the relative dielectric constant of the liquid crystal molecules in the first region 602 and the second region 603, the better the fingerprint recognition effect that can be achieved when they are used in a touch panel.

[0072] The position information of the liquid crystal molecules can generally be determined by the pre-tilt angle and the azimuth angle. Referring to Figure 10 Figure 10 The liquid crystal molecule position information diagram provided by an embodiment of the present application is shown in the figure. The angle between the projection of the liquid crystal molecule 601 in the xy plane and the x axis is defined as the azimuth angle ψ, and the angle between the liquid crystal molecule 601 and its projection in the xy plane is defined as the pre-tilt angle θ. Therefore, when the liquid crystal layer is arranged in a touch panel, the plane of the touch panel can be used as the xy plane. When the liquid crystal molecule 601 is a negative liquid crystal molecule, the greater the pre-tilt angle of the liquid crystal molecule 601, the greater the relative dielectric constant. At this time, refer to Figure 9 and Figure 10 The pre-tilt angle of the liquid crystal molecule 601 in the first region 602 of the liquid crystal layer 6 is greater than the pre-tilt angle of the liquid crystal molecule 601 in the second region 603. For example, the pre-tilt angle of the liquid crystal molecule 601 in the first region 602 of the liquid crystal layer 6 can be greater than or equal to 45° and less than or equal to 90°, and the pre-tilt angle of the liquid crystal molecule 601 in the second region 603 can be greater than or equal to 0° and less than 45°.

[0073] Similarly, when the liquid crystal molecule 601 is a positive liquid crystal molecule, the smaller the pre-tilt angle of the liquid crystal molecule 601, the greater the relative dielectric constant. At this time, the pre-tilt angle of the liquid crystal molecule 601 in the first region 602 of the liquid crystal layer 6 can be greater than or equal to 0° and less than or equal to 45°, and the pre-tilt angle of the liquid crystal molecule 601 in the second region 603 can be greater than 45° and less than or equal to 90°.

[0074] Referring to Figure 11 ​In a possible embodiment of the present application, the display screen can further include a polarizer 4, which is arranged between the liquid crystal layer 6 and the touch panel 1.

[0075] An optical element that can change natural light into polarized light is called a polarizer (or polarizing plate, polarizing film, polarizing sheet). Light in which the light vector only vibrates in a fixed direction in the direction of light propagation is called plane polarized light, and is also called linearly polarized light because the trajectory of the light vector endpoint is a straight line. An optical element that realizes linearly polarized light is called a linear polarizer, also known as a polarizer. A polarizer usually has a polarization transmission axis, and natural light passing through the polarization axis becomes corresponding polarized light.

[0076] With reference to the above Figure 11 Since the polarizer 4 is arranged between the liquid crystal layer 6 and the touch panel 1, in order to reduce the modulation effect of the liquid crystal layer 6 on the light that has passed through the polarizer 4, the azimuthal angle direction of the liquid crystal molecules in the liquid crystal layer 6 is perpendicular to the transmission axis direction of the polarizer 6, that is, the long axis direction of the projection of the liquid crystal molecules in the liquid crystal layer 6 on the touch panel is perpendicular to the direction of the polarization transmission axis of the polarizer 4. In addition, the liquid crystal layer 6 itself has no absorption effect on light, and the arrangement of the liquid crystal layer 6 in the display screen has little effect on the power consumption of the display screen.

[0077] With reference to the above Figure 11 In addition to the above structure, the display screen provided by the present application can further include a display panel 3. The display panel 3 is arranged on the side of the touch panel 1 away from the liquid crystal layer 6, and in addition, an encapsulation layer 7 can be arranged between the display panel 3 and the touch panel 1. The encapsulation layer 7 can be, but is not limited to, a thin film encapsulation (TFE) layer, to play a role of encapsulation and protection of the display panel 3. In addition, it can be understood that the liquid crystal layer 6 provided by the above embodiments of the present application can be applied to various display screens that need to increase the relative dielectric constant. For example, but not limited to, it can be applied to organic light-emitting diode (OLED) display screens, liquid crystal display (LCD) display screens, micro light-emitting diode (micro-LED) display screens, and the like, which are not listed one by one.

[0078] The display screen provided in the embodiments of the present application is provided with a liquid crystal layer 6 between the touch panel 1 and the cover plate 5. Since the relative dielectric constant of the first area 602 in the liquid crystal layer 6 is greater than the relative dielectric constant of the second area 603, and the first area 602 is arranged opposite to the fingerprint sensing point of the touch panel, the induced voltage signal at the fingerprint recognition point can be increased, and the induced signal of other fingerprint sensing points around the fingerprint recognition point continues to attenuate with the increase of the distance from the ridge of the fingerprint, so that the steepness of the signal distribution curve caused by each fingerprint can be increased. When all the induced signals are superimposed, there will be fluctuations in the curve, so that the relative position of the ridge and the valley of the fingerprint can be determined, the shape of the fingerprint can be distinguished, and the purpose of fingerprint recognition can be achieved.

[0079] In addition, since the liquid crystal layer 6 does not need to be driven by a circuit, and the liquid crystal layer 6 itself has no absorption effect on light, the influence of the liquid crystal layer 6 on the power consumption of the display screen is small.

[0080] In order to further understand the display screen provided in the present application, in some embodiments, a preparation method of the display screen is further provided. In the embodiments of the present application, the preparation method of the display screen is described by taking the display screen including a cover plate, a polaroid, a liquid crystal layer and a touch panel as an example. Referring to Figures 12a to 12c The preparation method of the display screen can specifically include the following steps:

[0081] Step one: referring to Figure 12a The patterned alignment layer is made on the substrate 8 used to make the liquid crystal layer. In specific implementation, the substrate 8 can be divided into a plurality of first areas 602 and a second area 603 between any two adjacent first areas 602, and the alignment layer is respectively made in the first area 602 and the second area 603, wherein the alignment of the alignment layer 801a of the first area 602 is different from the alignment of the alignment layer 801b of the second area 603.

[0082] Step two: referring to Figure 12b ​In the step shown in FIG. 6, the liquid crystal molecules 601 are aligned on the alignment layer 801a in the first region 602 and the alignment layer 801b in the second region 603. The liquid crystal molecules 601 are oriented by the intermolecular forces between the liquid crystal molecules and the alignment layer material. The position of the liquid crystal molecules is mainly determined by the azimuth angle ψ and the pretilt angle θ. Generally, when the pretilt angle θ is between 0-10°, it is called horizontal alignment; when the pretilt angle θ is between 80-89.5°, it is called vertical alignment. Because the liquid crystal molecules 601 have anisotropy, there is a difference between the relative permittivity along the long axis and the short axis of the liquid crystal molecules 601. Therefore, when the pretilt angles of the liquid crystal molecules 601 are different, the equivalent relative permittivity of the liquid crystal molecules 601 will change. By patterning the alignment layer, the pretilt angle difference of the liquid crystal molecules 601 in the first region 602 and the second region 603 can be achieved, thereby achieving the regional difference in the relative permittivity. For example, when the liquid crystal molecules 601 are positive liquid crystal molecules, the liquid crystal molecules 601 in the first region 602 can be horizontally aligned, the liquid crystal molecules 601 in the second region 603 can be vertically aligned, and the equivalent relative permittivity of the liquid crystal molecules 601 in the first region 602 can be greater than the equivalent relative permittivity of the liquid crystal molecules 601 in the second region 603.

[0083] It is worth mentioning that some liquid crystal molecules have groups that can undergo polymerization reaction. Under the condition of heating or light, the groups of each molecule react to form a chain, and the original small molecules are combined into polymer macromolecules. The liquid crystal loses the liquid flowability and is converted into a solid state.

[0084] Therefore, in the embodiments of the present application, Figure 12b After the liquid crystal molecules 601 are aligned in the step shown in FIG. 6, the liquid crystal molecules 601 can be cured into a film material by a photo-curing or thermal-curing method, and then the substrate is peeled off to obtain the liquid crystal layer 6 shown in FIG. 6. The equivalent relative permittivity of the first region 602 of the liquid crystal layer 6 is greater than the equivalent relative permittivity of the second region 603. Figure 12c

[0085] In addition, after the liquid crystal material forms an independent layer structure, the liquid crystal layer can be attached between the polarizing sheet and the cover plate. In addition, the long axis direction of the projection of the liquid crystal molecules in the liquid crystal layer on the polarizing sheet can be perpendicular to the direction of the polarization transmission axis of the polarizing sheet. Therefore, the modulation effect of the liquid crystal layer on the outgoing light after passing through the polarizing sheet can be reduced. In addition, the liquid crystal layer itself has no absorption effect on light, and the influence of the liquid crystal layer on the power consumption of the display screen is small.

[0086] ​After the cover plate, the polarizer and the liquid crystal film are assembled, the side of the polarizer away from the liquid crystal layer can be attached to the touch panel, and the projection of the area (the first area) of the liquid crystal layer with a relatively large dielectric constant on the touch panel covers the fingerprint sensing point on the touch panel.

[0087] Since the liquid crystal molecules can also rotate under the action of an electric field, based on this characteristic, referring to Figure 13 , a patterned electrode design can be made on the substrate. Specifically, in the implementation, the first electrode 802a and the second electrode 802b can be respectively arranged in the second area 603 on both sides of the first area 602 of the substrate, and no electrode is arranged in the first area 602. In this way, the difference between the pre-tilt angle of the liquid crystal molecules 601 and the relative dielectric constant in different areas can be set by the action of the electric field.

[0088] In some possible embodiments of the present application, the liquid crystal layer can also be formed by directly coating the alignment layer and the liquid crystal layer on the polarizer or the cover plate, so that the process step of peeling off the liquid crystal film and attaching the film material can be omitted. The specific preparation method can refer to the above-mentioned embodiments, and will not be described here.

[0089] The display screen obtained by the preparation method of the display screen provided in the embodiments of the present application is provided with a liquid crystal layer 6 between the touch panel 1 and the cover plate 5. Since the relative dielectric constant of the first area 602 in the liquid crystal layer 6 is greater than that of the second area 603, and the first area 602 is arranged opposite to the fingerprint sensing point of the touch panel, the induced voltage signal at the fingerprint recognition point can be increased, and the induced signal of other fingerprint sensing points around the fingerprint recognition point can continuously attenuate as the distance from the ridge of the fingerprint increases, so that the steepness of the signal distribution curve caused by each fingerprint can be increased. When all the induced signals are superimposed, the curve fluctuates, so that the relative position of the ridge and the valley of the fingerprint can be determined, the shape of the fingerprint can be distinguished, and the purpose of fingerprint recognition can be achieved.

[0090] In addition, since the liquid crystal layer 6 does not need to be driven by a circuit, and the liquid crystal layer 6 itself has no absorption effect on light, the influence of the liquid crystal layer 6 on the power consumption of the display screen is small.

[0091] Referring to Figure 14 , the embodiments of the present application also provide an electronic device, which can include the display screen provided in the above-mentioned embodiments. The electronic device can be but is not limited to a display, a television, a mobile phone, a notebook computer, an automobile display lamp, a smart watch, etc.

[0092] In addition, the electronic device can further include a back cover (not shown in the figure) and a middle frame (not shown in the figure) in addition to the display screen. The middle frame serves as a support structure and supports the display screen and the back cover. The display screen and the back cover are arranged on two sides of the middle frame and are fixedly connected to the middle frame.

[0093] The display screen of the electronic device of the present application is provided with a liquid crystal layer 6 between the touch panel 1 and the cover plate 5. Since the relative dielectric constant of the first area 602 of the liquid crystal layer 6 is greater than the relative dielectric constant of the second area 603, and the first area 602 is arranged opposite the fingerprint sensing point of the touch panel, the induced voltage signal at the fingerprint recognition point can be increased, and the induced signal of other fingerprint sensing points around the fingerprint recognition point continues to attenuate as the distance from the ridge of the fingerprint increases. Thus, the steepness of the curve of the signal distribution caused by each fingerprint can be increased. When all the induced signals are superimposed, there will be fluctuations in the curve, thereby determining the relative position of the ridge and valley of the fingerprint, distinguishing the shape of the fingerprint, and achieving the purpose of fingerprint recognition.

[0094] In addition, since the liquid crystal layer 6 does not need to be driven by a circuit, and the liquid crystal layer 6 itself has no absorption effect on light, the influence of the liquid crystal layer 6 on the power consumption of the display screen is small.

[0095] Continuing to refer to Figure 14 In one possible embodiment of the present application, the projection of the touch area 9 of the display screen on the liquid crystal layer 6 can be within the boundary range of the liquid crystal layer 6, so that fingerprint recognition can be achieved when the finger touches the touch area 9, reducing the user's recognition process of the fingerprint recognition area, thereby improving the user experience.

[0096] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art can easily think of changes or replacements within the technical scope disclosed in the present application, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A display screen, characterized in that, The display screen includes a cover plate, a touch panel, and a liquid crystal layer, wherein the liquid crystal layer is disposed between the cover plate and the touch panel, wherein: The touch panel includes a first layer structure, a second layer structure, multiple signal transmitting lines and multiple signal receiving lines. The multiple signal transmitting lines are disposed in the first layer structure, and the multiple signal receiving lines are disposed in the second layer structure. Along the stacking direction from the first layer structure to the second layer structure, multiple intersection positions between the projections of the multiple signal transmitting lines and the projections of the multiple signal receiving lines serve as multiple fingerprint sensing points. The liquid crystal layer includes a plurality of first regions and a second region located between any two adjacent first regions. The plurality of first regions are configured one-to-one with the plurality of fingerprint sensing points, and the projection of the first region on the touch panel covers the fingerprint sensing points configured therewith. The relative permittivity of the first region is greater than that of the second region. The liquid crystal layer is a film material.

2. The display screen as described in claim 1, characterized in that, The relative permittivity of the liquid crystal molecules in the first region of the liquid crystal layer is greater than or equal to 15 and less than or equal to 100; and / or, the relative permittivity of the liquid crystal molecules in the second region of the liquid crystal layer is greater than or equal to 2 and less than 15.

3. The display screen as described in claim 1 or 2, characterized in that, The liquid crystal molecules in the liquid crystal layer are negative liquid crystal molecules. The pretilt angle of the liquid crystal molecules in the first region is greater than or equal to 45° and less than or equal to 90°; the pretilt angle of the liquid crystal molecules in the second region is greater than or equal to 0° and less than 45°. Alternatively, the liquid crystal molecules in the liquid crystal layer are forward-oriented liquid crystal molecules, and the pretilt angle of the liquid crystal molecules in the first region is greater than or equal to 0° and less than or equal to 45°; the pretilt angle of the liquid crystal molecules in the second region is greater than 45° and less than or equal to 90°.

4. The display screen as described in claim 1 or 2, characterized in that, The area of ​​the first region of the liquid crystal layer is greater than or equal to 10μm×10μm.

5. The display screen as described in claim 1 or 2, characterized in that, The display screen also includes a polarizer disposed between the liquid crystal layer and the touch panel.

6. The display screen as described in claim 5, characterized in that, The long axis of the projection of the liquid crystal molecules in the liquid crystal layer onto the touch panel is perpendicular to the direction of the polarization transmission axis of the polarizer.

7. An electronic device, characterized in that, It includes a back cover, a middle frame, and a display screen as described in any one of claims 1 to 6, wherein the display screen and the back cover are disposed on both sides of the middle frame and are respectively fixedly connected to the middle frame.

8. A method for manufacturing a display screen, characterized in that, The display screen includes a polarizer, a cover plate, and a touch panel. The touch panel includes a first layer structure, a second layer structure, multiple signal transmission lines, and multiple signal receiving lines. The multiple signal transmission lines are disposed in the first layer structure, and the multiple signal receiving lines are disposed in the second layer structure. Along the stacking direction from the first layer to the second layer, multiple intersection points between the projections of the multiple signal transmission lines and the projections of the multiple signal reception lines serve as multiple fingerprint sensing points; the method includes: The substrate used to fabricate the liquid crystal layer is divided into multiple first regions and a second region located between any two adjacent first regions. Alignment layers are formed in the first regions and the second regions respectively, and the alignment of the alignment layers in the first regions and the alignment layers in the second regions are different. Liquid crystal materials are coated on the alignment layer in the first region and the alignment layer in the second region, respectively; The liquid crystal material is cured into a film, and the substrate is peeled off to obtain a liquid crystal layer. The relative permittivity of the liquid crystal molecules in the first region of the liquid crystal layer is greater than that of the liquid crystal molecules in the second region of the liquid crystal layer. The liquid crystal layer is bonded between the polarizer and the cover plate; The side of the polarizer facing away from the liquid crystal layer is attached to the touch panel; and the projection of the first region of the liquid crystal layer onto the touch panel covers the fingerprint sensor point of the touch panel.

9. The method for manufacturing a display screen as described in claim 8, characterized in that, The method further includes: The long axis of the projection of the liquid crystal molecules in the liquid crystal layer onto the polarizer is perpendicular to the direction of the polarization transmission axis of the polarizer.

Images