CN111856819B

CN111856819B - Backlight module, display module, fingerprint identification method of display module and display device

Info

Publication number: CN111856819B
Application number: CN202010879570.8A
Authority: CN
Inventors: 刘雨杰; 禹映雪; 张晓萍; 范利涛
Original assignee: BOE Technology Group Co Ltd; Beijing BOE Optoelectronics Technology Co Ltd
Current assignee: BOE Technology Group Co Ltd; Beijing BOE Optoelectronics Technology Co Ltd
Priority date: 2020-08-27
Filing date: 2020-08-27
Publication date: 2023-03-28
Anticipated expiration: 2040-08-27
Also published as: CN111856819A

Abstract

The application provides a backlight module, a display module, a fingerprint identification method of the backlight module and the display module, and a display device. The backlight module comprises: a light guide plate, an inverse prism and a privacy film. The inverse prism is positioned on the light-emitting surface of the light guide plate and is used for polymerizing the light emitted by the light guide plate to form polymerized light. The peep-proof film is positioned on one side, far away from the light guide plate, of the inverse prism and used for shielding the polymerization light rays at a certain angle so as to form collimated emergent light. Because the backlight module of this application embodiment has included inverse prism and peep-proof membrane, wherein, inverse prism is located the play plain noodles of light guide plate for the light that the polymerization light guide plate jetted out forms polymerization light, and peep-proof membrane is located inverse prism and keeps away from light guide plate one side, is used for sheltering from the polymerization light of certain angle, in order to form the emergent light of collimation. Therefore, under the combined action of the inverse prism and the peep-proof film, collimated light for identifying fingerprints is formed, the fingerprint identification accuracy is further improved, and the market competitiveness of the LCD display device is enhanced.

Description

Backlight module, display module, fingerprint identification method of display module and display device

Technical Field

The application relates to the technical field of display, in particular to a backlight module, a display module, a fingerprint identification method of the backlight module and a display device.

Background

With the increasing maturity of Organic Light-Emitting Diode (OLED) technology, more and more mobile phone products adopting OLEDs are used, and because the OLED technology does not need to adopt Liquid Crystal, the high-end phones in the mainstream brand mobile phones at present all adopt an in-screen fingerprint identification scheme to improve screen occupation ratio, which results in insufficient market competitiveness of Liquid Crystal Display (LCD) screens.

At present, two schemes of fingerprint identification sensors in an LCD are arranged On a color film substrate (On CF) and an Array substrate (On Array). However, the applicant finds that in the On CF scheme, due to the shielding property of the fingerprint identification sensor to the touch ITO layer, a normal touch function cannot be realized. In the ON Array scheme, the fingerprint sensor is disposed below the black matrix, and the fingerprint sensor is easily saturated after receiving light from the backlight source, and cannot perform fingerprint recognition.

Disclosure of Invention

In view of this, the present application provides a backlight module, a display module, a fingerprint identification method thereof, and a display device, for providing a technical solution capable of accurately identifying a fingerprint under an LCD display device.

In order to solve the above problem, the embodiments of the present application mainly provide the following technical solutions:

in a first aspect, an embodiment of the present application discloses a backlight module, including: a light guide plate, a reverse prism and a privacy film;

the inverse prism is positioned on the light-emitting surface of the light guide plate and is used for polymerizing the light emitted by the light guide plate to form polymerized light;

the peep-proof film is positioned on one side, far away from the light guide plate, of the inverse prism and used for shielding the polymerization light rays at a certain angle to form collimated emergent light.

Optionally, the backlight module further comprises a viewing angle switching film and a driving circuit;

the visual angle switching film is located the peep-proof film is kept away from inverse prism one side, drive circuit is used for doing the visual angle switching film outputs the driving electrical signal, so that the emergent light passes through take place the scattering behind the visual angle switching film, or make the emergent light passes through behind the visual angle switching film propagation direction is unchangeable.

Optionally, the viewing angle switching film comprises a first conductive layer, a functional layer and a second conductive layer which are laminated and arranged on one side of the peep-proof film far away from the inverse prism;

the first conducting layer and the second conducting layer are used for receiving the driving electric signal;

the functional layer is used for enabling the emergent light to be scattered or enabling the transmission direction of the emergent light to be unchanged under the control of the first conducting layer and the second conducting layer.

Optionally, the viewing angle switching film further comprises a first protective layer and a second protective layer;

the first protective layer is positioned on one side, close to the peep-proof film, of the first conductive layer;

the second protective layer is positioned on one side, away from the peep-proof film, of the second conductive layer;

the functional layer is a polymer dispersed liquid crystal layer.

In a second aspect, an embodiment of the present application discloses a display module, including: a liquid crystal display panel, a chip on film and the backlight module of the first aspect;

the liquid crystal display panel comprises a fingerprint identification sensor.

Optionally, the display module comprises a main board, a fingerprint identification chip and a touch display control chip, and the fingerprint identification chip and the touch display control chip are integrated on the chip on film;

the flip chip film is connected with the mainboard through a flexible circuit board.

Optionally, the liquid crystal display panel includes an array substrate and a color film substrate that are disposed opposite to each other, and the fingerprint sensor is integrated on the array substrate.

In a third aspect, an embodiment of the present application discloses a display device, including the display module set described in the second aspect.

In a fourth aspect, an embodiment of the present application discloses a fingerprint identification method for a display module according to the second aspect, including:

receiving a reset electrical signal, and resetting the fingerprint identification sensor;

the fingerprint identification sensor receives the collimated emergent light to collect fingerprint information input by a fingerprint identification area and outputs the fingerprint information to a fingerprint identification chip, and the fingerprint identification chip processes the fingerprint information and then sends the processed fingerprint information to the mainboard;

and the mainboard compares the processed fingerprint information with preset fingerprint information, determines that the fingerprint information and the preset fingerprint information are the same, and outputs a display signal to the touch display control chip so as to control the liquid crystal display panel to normally display.

Optionally, when the backlight module includes a viewing angle switching film and a driving circuit, before resetting the fingerprint sensor, the method further includes:

the driving circuit outputs a high-level signal, so that the transmission direction of the emergent light is unchanged after passing through the visual angle switching film, and the fingerprint identification sensor receives the collimated emergent light;

the determining that the two are the same further comprises:

the driving circuit outputs a preset level signal so that the emergent light is scattered after passing through the visual angle switching film.

By means of the technical scheme, the technical scheme provided by the embodiment of the application at least has the following advantages:

because backlight unit of this application embodiment has included inverse prism and peep-proof membrane, wherein, inverse prism is located the play plain noodles of light guide plate for the light that the polymerization light guide plate jetted out forms the polymerization light, and peep-proof membrane is located inverse prism and keeps away from light guide plate one side, is used for sheltering from the polymerization light of certain angle, in order to form the emergent light of collimation. Consequently, this application embodiment is under the combined action of inverse prism and peep-proof membrane, and backlight unit can form the emergent light of collimation, and when the fingerprint identification sensor scheme of backlight unit collocation ON Array in this application embodiment, the emergent light of collimation makes the difficult emergence saturation of fingerprint identification sensor, thereby can be fine realize that fingerprint identification has strengthened LCD display device's market competition.

The foregoing description is only an overview of the technical solutions of the embodiments of the present application, and the embodiments of the present application can be implemented according to the content of the description in order to make the technical means of the embodiments of the present application more clearly understood, and the detailed description of the embodiments of the present application will be given below in order to make the foregoing and other objects, features, and advantages of the embodiments of the present application more clearly understandable.

Drawings

Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the alternative embodiments. The drawings are only for purposes of illustrating alternative embodiments and are not to be construed as limiting the embodiments of the present application. Also, like reference numerals are used to refer to like parts throughout the drawings. In the drawings:

fig. 1 is a schematic structural diagram of a backlight module according to an embodiment of the present application;

FIG. 2 is a schematic diagram of a ray of light passing through an inverse prism according to an embodiment of the present application;

fig. 3 is a schematic structural view of a privacy film according to an embodiment of the present application;

fig. 4 is a schematic structural view of a viewing angle switching film according to an embodiment of the present application;

fig. 5 is a schematic structural diagram of a fingerprint identification chip and a touch display control chip according to an embodiment of the present application;

FIG. 6 is a flow chart of a first embodiment of the fingerprint identification principle of an embodiment of the present application;

FIG. 7 is a flow chart of a second embodiment of the fingerprinting principles of an embodiment of the present application;

FIG. 8 is a timing diagram of a display module according to an embodiment of the present disclosure;

FIG. 9 is a flowchart illustrating a fingerprint identification method of a display module according to an embodiment of the present disclosure;

fig. 10 is a driving circuit diagram of a fingerprint recognition sensor according to an embodiment of the present application.

The reference numerals are introduced as follows:

1-a backlight module; 2-a light guide plate; 3-inverse prism; 4-a peep-proof membrane; 41-a spacer layer; 42-a peep-proof piece; 5-view switching film; 51-a first conductive layer; 52-a functional layer; 53-a second conductive layer; 54-a first protective layer; 55-a second protective layer; 6-a reflective layer; 7-a frame; 71-light-shielding adhesive tape; 8-a light emitting source; 9-a driver circuit;

10-a display module; 11-a liquid crystal display panel; 12-chip on film; 13-a fingerprint recognition sensor; 14-a main board; 15-fingerprint identification chip; 16-touch display control chip; 17-a flexible circuit board; 18-touch detection unit.

Detailed Description

Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be embodied in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

As used herein, the singular forms "a", "an", "the" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. It is to be understood that the term "and/or" as used herein is intended to include all or any and all combinations of one or more of the associated listed items.

It will be understood by those within the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the prior art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

The applicant finds that in the ON Array scheme of the existing fingerprint identification sensor, because the fingerprint identification sensor is arranged below the black matrix and the existing conventional backlight is a surface light source, the fingerprint identification sensor is easily saturated after receiving the light of the backlight source, and cannot perform fingerprint identification.

In view of this, the embodiment of the present application provides a new backlight unit to in the fingerprint identification stage, the light that the backlight sent no longer is the area light source, reduces the light that fingerprint identification sensor received the backlight, makes fingerprint identification sensor can carry out fingerprint identification.

The backlight module provided by the embodiment of the present application is described in detail below with reference to the accompanying drawings.

In a first aspect, fig. 1 shows a backlight module 1 of an embodiment of the present application. As shown in fig. 1, the backlight module 1 includes: a light guide plate 2, a reverse prism 3 and a peep-proof film 4. The inverse prism 3 is located on the light emitting surface of the light guide plate 2, and is used for converging the light emitted from the light guide plate 2 to form a converged light. The peep-proof film 4 is positioned on one side of the inverse prism 3, which is far away from the light guide plate 2, and is used for shielding the polymerization light rays with a certain angle so as to form collimated emergent light.

Because backlight unit 1 of this application embodiment has included inverse prism 3 and peep-proof membrane 4, wherein, inverse prism 3 is located the play plain noodles of light guide plate 2 for the light that 2 jets out of polymerization light guide plate forms the polymerization light, and peep-proof membrane 4 is located inverse prism 3 and keeps away from light guide plate 2 one side, is used for sheltering from the polymerization light of certain angle, with the emergent light that forms the collimation. Consequently, this application embodiment is under the combined action of contrary prism 3 and peep-proof membrane 4, and backlight unit 1 can form the emergent light of collimation, and when the fingerprint identification sensor scheme of 1 collocation ON Array of backlight unit in this application embodiment, the emergent light of collimation makes the difficult emergence saturation of fingerprint identification sensor, thereby can be fine realize that fingerprint identification has strengthened LCD display device's market competition.

In particular, fig. 2 shows the light ray profile as it passes through the inverse prism 3 and the privacy film 4. As shown in fig. 1 and fig. 2, the backlight module 1 of the embodiment of the present application further includes a reflective layer 6, a frame 7 and a light emitting source 8, where the frame 7 is used to fix the light guide plate 2, the inverse prism 3, the peep-proof film 4 and the reflective layer 6, and the specific arrangement manner of the frame 7 is similar to that of the prior art and is not described herein again. A light emitting source 8 is disposed between the light guide plate 2 and the frame 7 (i.e., on one side of the light incident surface of the light guide plate 2), and the specific arrangement manner of the light emitting source 8 is similar to that of the side-in backlight in the prior art, and is not described herein again. The reflecting layer 6 is arranged on one side, far away from the inverse prism 3, of the light guide plate 2 and used for reflecting light rays into the light guide plate 2, and therefore the utilization rate of the light rays is improved. In addition, the backlight module 1 further includes a light-shielding tape 71, and the light-shielding tape 71 is used for preventing light leakage.

As shown in fig. 2, when the light source 8 is driven to emit light, the light emitted from the light source 8 enters the light guide plate 2 through the light entrance surface of the light guide plate 2, the surface of the light guide plate 2 is processed with a special microstructure to keep the included angle between the emitted light and the horizontal plane at about 15 degrees, the light emitting angle is controlled within 10 degrees, and the light emitted from the light guide plate 2 enters the inverse prism 3 and is emitted after being totally reflected in the inverse prism 3. Compare with prior art backlight unit's structure that adopts double prism, the contrary prism 3 in this application embodiment can promote backlight unit luminance through the beam angle who contracts vertical direction and horizontal direction.

Fig. 3 shows a specific structure of the privacy film 4. As shown in fig. 3, the privacy film 4 includes two spacer layers 41 and a plurality of privacy members 42 that are oppositely disposed. The peep-proof members 42 are arranged between the spacer layers 41 with a certain distance between two adjacent peep-proof members 42. When the polymerization light passes peep-proof membrane 4, peep-proof piece 42 of peep-proof membrane 4 can shelter from the polymerization light of certain angle to form the emergent light of collimation, during the concrete implementation, peep-proof membrane 4 in the embodiment of this application can adopt the peep-proof membrane that prior art was commonly used, does not have the setting degree of difficulty.

The effect of reverse prism 3 of this application embodiment is mainly polymerization level and vertical direction's light to promote light-emitting brightness, peep-proof membrane 4's effect shelters from the light of specific angle, and this application embodiment forms the collimated light that satisfies the luminance specification under reverse prism 3 and peep-proof membrane 4's combined action.

Because the peep-proof film 4 is arranged on the inverse prism 3, the peep-proof film 4 can shield non-vertical light when in use, the visual angle of a user is reduced, and inconvenience is caused when in use. In order to overcome the above problem, optionally, with continued reference to fig. 1, the backlight module 1 further includes a viewing angle switching film 5 and a driving circuit 9 (see fig. 7). The visual angle switching film 5 is located on one side, far away from the inverse prism 3, of the peep-proof film 4, and the driving circuit 9 is used for outputting a driving electric signal for the visual angle switching film 5 so that emergent light can be scattered after passing through the visual angle switching film 5 or the transmission direction of the emergent light is unchanged after passing through the visual angle switching film 5. By arranging the visual angle switching film 5, the driving circuit 9 outputs different driving electric signals according to actual use requirements (for example, when the driving electric signals are low level signals, emergent light can be scattered after passing through the visual angle switching film 5, and when the driving electric signals are high level signals, the transmission direction of the emergent light after passing through the visual angle switching film 5 can be unchanged), so that the transmittance and the haze of the visual angle switching film 5 can be changed, and the requirements of normal use of a user can be met.

The working principle of the viewing angle switching film 5 is described in detail below:

the viewing angle switching film 5 of the embodiment of the present application has two different states according to the level difference, where table 1 shows specific parameters of the light transmittance and the haze of the viewing angle switching film 5 when the driving circuit outputs a low level and a high level to the viewing angle switching film 5. When the driving circuit outputs low level (0V), the emergent light is scattered after passing through the visual angle switching film 5, at the moment, the state of the visual angle switching film 5 corresponds to a normal display stage, and the wide visual angle picture can enable the display device to normally display information, so that a user can conveniently read the information. When the driving circuit outputs a high level (12V), the propagation direction of the emergent light passing through the viewing angle switching film 5 is unchanged, the viewing angle switching film 5 is in a peep-proof state at the moment, the peep-proof state corresponds to the fingerprint identification stage, the viewing angle is narrowed at the moment, and the light vertically passes through the viewing angle switching film 5 and is used for fingerprint identification.

TABLE 1

Optical parameters	Low level of electricity	High level
			Light transmittance (%)	91±1	88±1
Haze (%)	74±1	3.0±0.5

Considering the influence of the fingerprint identification sensor on the brightness of the backlight module 1, when the viewing angle switching film 5 is in a non-peep-proof state, it can be found that the viewing angle switching film 5 cannot provide a brightness range meeting the requirements of a user when receiving a low level. At this time, it is necessary to set an intermediate stage between the normal display stage and the fingerprint recognition stage, where the intermediate stage is set according to the voltage of the driving circuit 9, the voltage is different, and the transmittance of the viewing angle switching film 5 is also different, that is, the embodiment of the present application needs to set an intermediate level between the low level and the high level that can satisfy the brightness requirement of the user. Through experiments and repeated tests, table 2 provides transmittance parameter values of the viewing angle switching film 5 at different voltages. As shown in table 2, in the normal case, the luminance accepted by most users is the case where the level voltage value is 3V and the transmittance is 58.6%. It should be noted, however, that the selection of the intermediate level may need to be selected according to the different requirements of the customer on the brightness.

TABLE 2

Alternatively, as shown in fig. 4, the viewing angle switching film 5 in the embodiment of the present application includes a first conductive layer 51, a functional layer 52, and a second conductive layer 53 stacked on the side of the privacy film 4 remote from the inverse prism 3. The first conductive layer 51 and the second conductive layer 53 are for receiving a driving electric signal. And a functional layer 52 for scattering the emitted light or making the propagation direction of the emitted light unchanged under the control of the first conductive layer 51 and the second conductive layer 53. In actual design, the first conductive layer 51 and the second conductive layer 53 are electrically connected to the driving circuit 9, and a voltage output from the driving circuit 9 is applied to the functional layer 52 through the first conductive layer 51 and the second conductive layer 53, so that emitted light is scattered or the propagation direction of the emitted light is not changed.

Specifically, the functional layer 52 in the embodiment of the present application is a polymer dispersed liquid crystal layer, and the first conductive layer 51 and the second conductive layer 53 apply different voltages to liquid crystal molecules in the polymer dispersed liquid crystal layer, so that the liquid crystal molecules have different deflection angles, thereby enabling emitted light to be scattered or enabling the propagation direction of the emitted light to be unchanged.

Alternatively, with continued reference to fig. 4, in order to isolate the first conductive layer 51 and the second conductive layer 53 from other coating layers and ensure normal use of the viewing angle switching film 5, the viewing angle switching film 5 of the embodiment of the present application further includes a first protective layer 54 and a second protective layer 55. The first protective layer 54 is located on the side of the first conductive layer 51 close to the privacy film 4. The second protective layer 55 is located on the side of the second conductive layer 53 remote from the privacy film 4.

In specific implementation, the first conductive layer 51 and the second conductive layer 53 in this embodiment are transparent conductive layers, and the first conductive layer 51 and the second conductive layer 53 may be made of the same material, such as: the first conductive layer 51 and the second conductive layer 53 may be formed using Indium Tin Oxide (ITO), indium Zinc Oxide (IZO), or a mixture of ITO and IZO. The first protective layer 54 and the second protective layer 55 may be made of insulating and light-transmitting materials, such as: the first protective layer 54 and the second protective layer 55 may use a silicon oxide or silicon nitride material.

Based on the same inventive concept, in a second aspect, fig. 5 to 7 respectively show the display module 10 of the embodiment of the present application. As shown in fig. 5, the display module 10 includes: a liquid crystal display panel 11, a Chip On Film (COF) 12, and the backlight module 1 of the first aspect (not shown in the drawings, the specific structure of the backlight module 1 can refer to fig. 1). Certainly, the display module assembly 10 of the embodiment of the present application can identify the fingerprint, thereby opening the normal display interface of the display device. Therefore, the liquid crystal display panel 11 should include the fingerprint recognition sensor 13.

The display module assembly 10 of the embodiment of the application has included backlight unit 1 of the first aspect, under the combined action of reverse prism 3 and peep-proof membrane 4, forms the collimated light that is used for discerning the fingerprint, further promotes the precision of discerning the fingerprint, strengthens the competitiveness of LCD display device on market.

Optionally, with continued reference to fig. 5-7, the display module 10 includes a main board 14, a fingerprint identification chip 15 and a touch display control chip 16, and both the fingerprint identification chip 15 and the touch display control chip 16 are integrated on the chip on film 12. The chip on film 12 is connected to the motherboard 14 via the flexible circuit board 17. Because the fingerprint identification chip 15 and the touch display control chip 16 of the embodiment of the application are integrated on the chip on film 12, the complexity of manufacturing the display module 10 is greatly simplified, the possibility of mass production of the display module 10 is realized, and the requirement of a narrow frame of the module can be met. In addition, the fingerprint identification chip 15 and the touch display control chip 16 may be integrated into one IC (integrated circuit chip) later.

Optionally, in an optional embodiment, the liquid crystal display panel 11 includes an array substrate and a color filter substrate that are disposed opposite to each other, and the fingerprint sensor 13 is integrated on the array substrate. The specific setting mode of the fingerprint sensor 13 is similar to the setting mode of the fingerprint sensor 13 in the ON Array scheme of the fingerprint sensor in the prior art, and is not described again here.

The fingerprint identification principle of the display module 10 according to the embodiment of the present application is described in detail below with reference to fig. 6 to 8:

fig. 6 illustrates a principle of fingerprint recognition when the viewing angle switching film 5 is not provided in the display module 10 according to the embodiment of the present application. Fig. 7 illustrates a fingerprint recognition principle of the display module 10 according to the embodiment of the present application after the viewing angle switching film 5 is disposed. Fig. 8 shows a time sequence of the display module 10 in the normal display phase and the fingerprint identification phase according to the embodiment of the present application.

For convenience of understanding, first, the chinese names and their usage of the respective english acronyms in fig. 6-8 will be explained. In the case of figures 6 and 7,

the SPI is a Serial Peripheral Interface (Serial Peripheral Interface) used for transmitting the fingerprint image and the coordinates of the finger point.

The AFE is an Analog Front End interface (Analog Front End) and is configured to receive Analog signals output by the fingerprint sensor and the touch sensor.

And the I2C is an I2C serial communication interface and is used for transmitting the coordinates of the finger point.

The MIPI is a Mobile Industry Processor Interface (Mobile Industry Processor Interface) for transmitting display image information.

AC is an alternating current Circuit unit (AC Circuit) for receiving and outputting an appropriate alternating current signal.

TC, the fingerprint identification chip 15 outputs corresponding area selection signals after confirming the identification area according to the finger coordinates.

In addition, the display module 10 of the embodiment of the application is further provided with a touch detection unit for detecting whether the finger of the user touches the display surface of the display module 10.

In fig. 8, TE is a synchronization signal of the fingerprint identification chip 15 and the touch display control chip 16, wherein in the fingerprint identification phase, when the level voltage of TE is a high voltage, the display module 10 is in an off state, and when the level voltage of TE is a low voltage, the display module 10 is in an on state; in the normal use phase, the level voltage of TE is low, and the display module 10 is in the on state.

Sensor gate1.. Sensor gate N is a switching signal of the fingerprint recognition sensors of the first to nth rows.

The LFD is a same-driving Free Driver (Loading Free Driver) for preventing the power signal of the display and the fingerprint from affecting the touch operation during the touch.

D-VHG/L-G is a power supply signal of the same-drive signal driver.

The PDLC is a voltage signal output by a driving circuit 9 of the visual angle switching film 5, and in the fingerprint identification stage, the driving circuit 9 outputs a high-level signal with the maximum light transmittance and the minimum haze; in the normal display stage, the driving circuit 9 outputs a low level signal or outputs an intermediate level signal according to a setting, providing a viewing angle and brightness satisfying the customer's needs. The drive circuit 9 is connected to the main board 14 through a flexible circuit board.

In the embodiment shown in fig. 6, when a finger of a user touches the liquid crystal display panel 11, the touch detection unit 18 detects the finger, generates a touch analog signal of a finger point coordinate and transmits the touch analog signal to the touch display control chip 16 through the AFE, the touch display control chip 16 converts the touch analog signal of the finger point coordinate into a touch digital signal of a finger point coordinate and transmits the touch digital signal of the finger point coordinate to the motherboard 14 through the I2C, the motherboard 14 determines that the liquid crystal display panel 11 is touched according to the touch digital signal and transmits a display signal to the touch display control chip 16 through the MIPI, and the touch display control chip 16 outputs a display driving signal to drive the liquid crystal display panel 11 to display a fingerprint identification desktop (i.e., to display a picture of a specific fingerprint identification area).

Meanwhile, as shown in fig. 6, the fingerprint identification chip 15 sends a fingerprint identification sensor driving signal of a corresponding area according to a finger coordinate signal sent by the main board 14 through the SPI, after the fingerprint identification sensor 13 detects a fingerprint of a user, a fingerprint analog signal of a fingerprint image is transmitted to the fingerprint identification chip 15 through the AFE, and the fingerprint identification chip 15 converts the fingerprint analog signal into a fingerprint digital signal and transmits the fingerprint digital signal to the main board 14 through the SPI. The main board 14 performs a fingerprint recognition algorithm on the fingerprint digital signal, compares the obtained fingerprint image with an image prestored in the main board 14, generates screen driving information, transmits the screen driving information to the touch display control chip 16 through the MIPI, and finally transmits the screen driving information to the liquid crystal display panel 11 through the touch display control chip 16 so as to drive the liquid crystal display panel 11 to normally display.

In another embodiment shown in fig. 7, the operation modes of the fingerprint identification chip 15 and the touch display control chip 16 are similar to those of the embodiment in fig. 6, and are not repeated herein. What is different, the backlight module 1 at this time is provided with the viewing angle switching film 5, in order to ensure that the input voltage of the viewing angle switching film 5 is adjustable, a screen brightness feedback signal needs to be introduced, the screen brightness feedback signal is output to the main board 14 by the touch display control chip 16, and the main board 14 outputs a corresponding alternating current signal to the driving circuit 9 through an alternating current circuit unit in the main board 14 according to the brightness information, so that the viewing angle switching film 5 can perform free switching of transmittance.

Based on the same inventive concept, in a third aspect, an embodiment of the present application discloses a display device, which includes the display module 10 of the second aspect. Since the display device of the third aspect includes the display module 10 of the second aspect, the display device of the third aspect has the same beneficial effects as the display module 10 of the second aspect. Therefore, the advantageous effects of the display device of the third aspect will not be repeated.

Based on the same inventive concept, in a fourth aspect, fig. 9 illustrates a fingerprint identification method of the display module 10 according to the second aspect of the embodiment of the present application. As shown in fig. 9, the method includes:

s101: and receiving a reset electrical signal to reset the fingerprint identification sensor 13.

S102: the fingerprint identification sensor 13 receives the collimated emergent light to collect fingerprint information input in a fingerprint identification area, and outputs the fingerprint information to the fingerprint identification chip 15, and the fingerprint identification chip 15 processes the fingerprint information and then sends the processed fingerprint information to the mainboard 14.

S103: the main board 14 compares the processed fingerprint information with the preset fingerprint information, determines that the processed fingerprint information and the preset fingerprint information are the same, and outputs a display signal to the touch display control chip 16 to control the liquid crystal display panel 11 to normally display.

It should be noted that the fingerprint information acquired by the fingerprint identification sensor 13 includes a fingerprint image, the fingerprint image is sent to the fingerprint identification chip 15 in an analog signal manner, and the fingerprint identification chip 15 processes the analog signal of the fingerprint image, forms a digital signal of the fingerprint image after processing, and transmits the digital signal to the main board 14.

It should be noted that controlling the display in the normal display of the liquid crystal display panel 11 means that the liquid crystal display panel 11 performs normal display information, and as shown in fig. 8, the normal display here means display in the normal use state. In the actual working process, the fingerprint identification state also exists in a display frame, and a picture of a specific fingerprint identification area is displayed in the display frame.

Specifically, the fingerprint identification sensor 13 receives collimated emergent light to collect fingerprint information input by the fingerprint identification area, and includes: collimated backlight emergent light penetrates through the liquid crystal display module and finally penetrates through the glass cover plate to reach the interface of the finger and the glass, and due to the fact that the direction is fixed, stray light interference is small, and the fingerprint identification sensor 13 cannot be saturated. Collimated light sees through glass apron and liquid crystal display module assembly once more through the finger reflection, is caught by fingerprint identification sensor 13, because the reverberation of fingerprint peak and millet is different, and fingerprint identification sensor 13 received light and shines differently, and the energy that realizes photoelectric conversion has the difference, can accomplish the collection to fingerprint information.

According to the embodiment of the application, more accurate fingerprint coordinate information is obtained through collimated light, so that when the main board 14 is used for fingerprint comparison, the comparison result is more accurate and faster; the fingerprint identification method is used for the LCD display device, and market competitiveness of the LCD display device is improved.

Optionally, when the backlight module 1 includes the viewing angle switching film 5 and the driving circuit, before resetting the fingerprint sensor, the method further includes:

the driving circuit outputs a high level signal, so that the transmission direction of the emergent light is unchanged after passing through the visual angle switching film 5, and the fingerprint identification sensor 13 receives the collimated emergent light;

determining that the two are the same, further comprising:

the driving circuit outputs a preset level signal so that the emergent light is scattered after passing through the viewing angle switching film 5.

Fig. 10 shows a driving circuit of the fingerprint recognition sensor 13 according to the embodiment of the present application. The fingerprint recognition sensor 13 is an active pixel sensor. As shown in fig. 10, the control terminal of the first thin film transistor T1 is connected to the voltage control terminal VGate, the first terminal thereof is connected to the first terminal of the second thin film transistor T2, and the second terminal thereof is connected to the current output terminal I _ OUT. The control terminal of the second thin film transistor T2 is connected to the first terminal of the third thin film transistor T3, the light emitting device, and one terminal of the capacitor, respectively, the first terminal is connected to the first terminal of the first thin film transistor T1, and the second terminal is connected to the power supply terminal VDD. The control terminal of the third thin film transistor T3 is connected to the voltage reset terminal VRST, the first terminal is connected to the control terminal of the second thin film transistor T2, the light emitting device and the capacitor, respectively, and the second terminal is connected to the voltage reset terminal VReset. The light emitting device and the capacitor are also respectively connected to the voltage bias terminal VBias. The light-emitting device and the capacitor form a fingerprint identification sensor, and the first thin film transistor T1, the second thin film transistor T2 and the third thin film transistor T3 are all N-type thin film transistors.

During fingerprint identification, the fingerprint identification sensor is in a reset phase, an acquisition phase and a reading phase, wherein

A reset stage: the voltage reset terminal VRST outputs a high level signal, the third thin film transistor T3 is turned on, and the voltage reset terminal VReset outputs a reset electrical signal to reset the fingerprint identification sensor.

An acquisition stage: the voltage reset end is pulled down, namely the voltage reset end VRST outputs a low level signal, the third thin film transistor T3 is closed, the fingerprint identification sensor receives collimated emergent light, photoelectric signals are accumulated in a circuit of the fingerprint identification sensor, and signal amplification is carried out through the second thin film transistor T2 and the power supply end VDD.

A reading stage: after the collection phase, the voltage control terminal VGate is pulled high, that is, the voltage control terminal VGate outputs a high level signal, so as to turn on the first thin film transistor T1, and the fingerprint identification chip 15 can read the signal of the current output terminal I _ OUT.

The beneficial effects obtained by applying the embodiment of the application comprise:

1. because backlight unit 1 of this application embodiment has included inverse prism 3 and peep-proof membrane 4, wherein, inverse prism 3 is located the play plain noodles of light guide plate 2 for the light that 2 jets out of polymerization light guide plate forms the polymerization light, and peep-proof membrane 4 is located inverse prism 3 and keeps away from light guide plate 2 one side, is used for sheltering from the polymerization light of certain angle, with the emergent light that forms the collimation. Consequently, this application embodiment is under the combined action of reverse prism 3 and peep-proof membrane 4, and backlight unit 1 can form the emergent light of collimation, and when the fingerprint identification sensor scheme of backlight unit 1 collocation ON Array in this application embodiment, the emergent light of collimation makes the difficult emergence saturation of fingerprint identification sensor, thereby can be fine realize fingerprint identification and strengthened LCD display device's market competition.

2. Because backlight unit 1 of this application embodiment includes inverse prism 3, compares with prior art backlight unit adoption double prism's structure, inverse prism 3 in this application embodiment can promote backlight unit luminance through the beam angle of contracting vertical direction and horizontal direction.

3. Because the backlight module 1 of the embodiment of the present application further sets the viewing angle switching film 5 on the side of the anti-peeping film 4 away from the inverse prism 3, the viewing angle switching film 5 changes the transmittance and the haze of the viewing angle switching film 5 according to the level of the level voltage output by the driving circuit 9, and can be suitable for the requirement of the normal use of the user.

4. Because of the embodiment of the application, the fingerprint identification chip 15 and the touch display control chip 16 are integrated on the chip on film 12, the complexity of manufacturing the display module 10 is greatly simplified, the possibility of mass production of the display module 10 is realized, and the requirement of a narrow frame of the module can be met.

Those of skill in the art will appreciate that the various operations, methods, steps in the processes, acts, or solutions discussed in this application can be interchanged, modified, combined, or eliminated. Further, other steps, measures, or schemes in various operations, methods, or flows that have been discussed in this application can be alternated, altered, rearranged, broken down, combined, or deleted. Further, steps, measures, schemes in the prior art having various operations, methods, procedures disclosed in the present application may also be alternated, modified, rearranged, decomposed, combined, or deleted.

In the description of the present application, it is to be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience in describing the present application and simplifying the description, but do not indicate or imply that the referred device or element must have a particular orientation, be constructed in a particular orientation, and be operated, and thus should not be construed as limiting the present application.

The terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present application, the meaning of "a plurality" is two or more unless otherwise specified.

It should be understood that, although the steps in the flowcharts of the figures are shown in order as indicated by the arrows, the steps are not necessarily performed in order as indicated by the arrows. The steps are not performed in the exact order shown and may be performed in other orders unless explicitly stated herein. Moreover, at least a portion of the steps in the flow chart of the figure may include multiple sub-steps or multiple stages, which are not necessarily performed at the same time, but may be performed at different times, which are not necessarily performed in sequence, but may be performed alternately or alternately with other steps or at least a portion of the sub-steps or stages of other steps.

The foregoing is only a few embodiments of the present application and it should be noted that those skilled in the art can make various improvements and modifications without departing from the principle of the present application, and that these improvements and modifications should also be considered as the protection scope of the present application.

Claims

1. A display module, comprising: the liquid crystal display device comprises a liquid crystal display panel, a chip on film and a backlight module;

the backlight module comprises: the display device comprises a light guide plate, an inverse prism, a peep-proof film, a visual angle switching film and a driving circuit;

the peep-proof film is positioned on one side of the inverse prism, which is far away from the light guide plate, and is used for shielding the polymerization light rays at a certain angle so as to form collimated emergent light; the peep-proof film comprises two spacing layers and a plurality of peep-proof pieces which are oppositely arranged; the peep-proof pieces are arranged between the spacing layers, and a certain distance is reserved between every two adjacent peep-proof pieces;

the visual angle switching film is positioned on one side, far away from the inverse prism, of the peep-proof film, and the driving circuit is used for outputting a driving electric signal for the visual angle switching film so as to enable the emergent light to be scattered after passing through the visual angle switching film or enable the propagation direction of the emergent light to be unchanged after passing through the visual angle switching film;

the liquid crystal display panel comprises a fingerprint identification sensor; in the fingerprint identification stage, the driving circuit outputs a high level signal; in a normal display stage, the driving circuit outputs a low level signal or outputs an intermediate level signal according to a setting.

2. The display module according to claim 1, wherein the viewing angle switching film comprises a first conductive layer, a functional layer and a second conductive layer laminated on a side of the privacy film away from the inverse prism;

3. The display module of claim 2, wherein the viewing angle switching film further comprises a first protective layer and a second protective layer;

the functional layer is a polymer dispersed liquid crystal layer.

4. The display module according to claim 1, comprising a main board, a fingerprint identification chip and a touch display control chip, wherein the fingerprint identification chip and the touch display control chip are integrated on the chip on film;

5. The display module according to claim 4, wherein the liquid crystal display panel comprises an array substrate and a color film substrate which are arranged oppositely, and the fingerprint sensor is integrated on the array substrate.

6. A display device, comprising the display module according to any one of claims 1 to 5.

7. A fingerprint identification method of a display module according to any one of claims 1 to 5, comprising:

receiving a reset electric signal and resetting the fingerprint identification sensor;

8. The fingerprint identification method according to claim 7, wherein when the backlight module comprises a viewing angle switching film and a driving circuit, before resetting the fingerprint identification sensor, the method further comprises:

the determining that the two are the same further comprises: