CN111856819A - Backlight module, display module and fingerprint identification method thereof, and display device - Google Patents

Abstract

The present application provides a backlight module, a display module, a fingerprint identification method thereof, and a display device. The backlight module includes: a light guide plate, an inverse prism and a privacy film. The inverse prism is located on the light-emitting surface of the light guide plate, and is used to aggregate the light emitted by the light guide plate to form aggregated light. The privacy film is located on the side of the inverse prism away from the light guide plate, and is used to block the aggregated light at a certain angle to form collimated outgoing light. Because the backlight module of the embodiment of the present application includes an inverse prism and a privacy film, wherein the inverse prism is located on the light-emitting surface of the light guide plate, and is used to aggregate the light emitted by the light guide plate to form aggregated light, and the privacy film is located away from the inverse prism. One side of the light guide plate is used to block the aggregated light at a certain angle to form collimated outgoing light. Therefore, under the combined action of the inverse prism and the anti-peep film, a collimated light for fingerprint identification is formed, which further improves the accuracy of fingerprint identification and enhances the competitiveness of the LCD display device in the market.

Description

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

technical field

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

Background technique

With the increasing maturity of Organic Light-Emitting Diode (OLED) technology, more and more mobile phone products use OLED. Since OLED technology does not need to use liquid crystal, the current mainstream brand mobile phones in high-end phones use in-screen fingerprint recognition. The solution is to increase the screen ratio, resulting in the lack of competitiveness of the liquid crystal display (Liquid Crystal Display, LCD) screen market.

At present, there are two solutions for fingerprint identification sensors in LCDs, which are arranged on the color filter substrate (On CF) and arranged on the array substrate (ON Array). However, the applicant found that in the On CF solution, due to the shielding property of the fingerprint recognition sensor to the touch ITO layer, the normal touch function cannot be realized. In the ON Array solution, since the fingerprint recognition sensor is set under the black matrix, the fingerprint recognition sensor is easily saturated after receiving the light from the backlight, and cannot perform fingerprint recognition.

SUMMARY OF THE INVENTION

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

In order to solve the above problems, 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, comprising: a light guide plate, an inverse prism, and a privacy film;

The inverse prism is located on the light emitting surface of the light guide plate, and is used to aggregate the light emitted by the light guide plate to form aggregated light;

The anti-peep film is located on the side of the inverse prism away from the light guide plate, and is used to block the aggregated light at a certain angle to form collimated outgoing light.

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

The viewing angle switching film is located on the side of the anti-peeping film away from the inverse prism, and the driving circuit is used for outputting a driving electric signal for the viewing angle switching film, so that the outgoing light passes through the viewing angle switching film. Scatter, or make the propagation direction of the outgoing light unchanged after passing through the viewing angle switching film.

Optionally, the viewing angle switching film includes a first conductive layer, a functional layer and a second conductive layer stacked on the side of the privacy protection film away from the inverse prism;

the first conductive layer and the second conductive layer are used for receiving the driving electrical signal;

The functional layer is used to scatter the outgoing light under the control of the first conductive layer and the second conductive layer, or to make the propagation direction of the outgoing light unchanged.

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

the first protective layer is located on the side of the first conductive layer close to the privacy film;

the second protective layer is located on the side of the second conductive layer away from the privacy film;

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 described in the first aspect;

The liquid crystal display panel includes a fingerprint recognition sensor.

Optionally, the display module includes a main board, a fingerprint identification chip and a touch display control chip, and both the fingerprint identification chip and the touch display control chip are integrated on the chip-on-chip;

The chip on film is connected to the main board through a flexible circuit board.

Optionally, the liquid crystal display panel includes an array substrate and a color filter substrate disposed opposite to each other, and the fingerprint recognition 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 described in the second aspect.

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

Receive a reset electrical signal to reset the fingerprint identification sensor;

The fingerprint identification sensor receives the collimated outgoing light to collect the fingerprint information input in the fingerprint identification area, and outputs the fingerprint information to the fingerprint identification chip, and the fingerprint identification chip processes the fingerprint information and sends it to the motherboard;

The motherboard compares the processed fingerprint information with the preset fingerprint information, and when it is determined that the two are the same, outputs a display signal to the touch display control chip to control the liquid crystal display panel to display normally.

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

The driving circuit outputs a high-level signal, so that the propagation direction of the outgoing light remains unchanged after passing through the viewing angle switching film, so that the fingerprint identification sensor receives the collimated outgoing light;

When it is determined that the two are the same, it also includes:

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

By means of the above technical solutions, the technical solutions provided by the embodiments of the present application have at least the following advantages:

Because the backlight module of the embodiment of the present application includes an inverse prism and a privacy film, wherein the inverse prism is located on the light exit surface of the light guide plate, and is used to aggregate the light emitted by the light guide plate to form aggregated light, and the privacy film is located at the inverse prism away from the guide plate. One side of the light plate is used to block the aggregated light at a certain angle to form collimated outgoing light. Therefore, under the combined action of the inverse prism and the privacy film in the embodiment of the present application, the backlight module can form collimated outgoing light. When the backlight module in the embodiment of the present application is matched with the fingerprint recognition sensor solution of ON Array, the The straight outgoing light makes the fingerprint identification sensor less likely to be saturated, and can well realize fingerprint identification, thereby enhancing the market competitiveness of the LCD display device.

The above description is only an overview of the technical solutions of the embodiments of the present application. In order to understand the technical means of the embodiments of the present application more clearly, it can be implemented according to the contents of the description. The advantages can be more obvious and easy to understand, and the specific implementations of the embodiments of the present application are described below.

Description of drawings

Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of alternative embodiments. The accompanying drawings are only for the purpose of illustrating optional embodiments, and are not considered to be limitations of the embodiments of the present application. Also, the same components are denoted by the same reference numerals throughout the drawings. In the attached image:

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

Fig. 2 is the route diagram when light passes through the inverse prism of the embodiment of the present application;

3 is a schematic structural diagram of a privacy protection film according to an embodiment of the present application;

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

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

FIG. 6 is a flowchart of the first embodiment of the fingerprint identification principle according to the embodiment of the present application;

FIG. 7 is a flowchart of the second embodiment of the fingerprint identification principle according to the embodiment of the present application;

8 is a timing diagram of a display module according to an embodiment of the present application;

9 is a flowchart of a fingerprint identification method of a display module according to an embodiment of the present application;

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

Reference numerals are introduced as follows:

1-backlight module; 2-light guide plate; 3-inverse prism; 4-privacy film; 41-spacer layer; 42-privacy part; 5-view switching film; 51-first conductive layer; 52-functional layer 53-second conductive layer; 54-first protective layer; 55-second protective layer; 6-reflection layer; 7-frame; 71-shading tape; 8-light source; 9-drive circuit;

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

Detailed ways

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 the present disclosure will be more thoroughly understood, and will fully convey the scope of the present disclosure to those skilled in the art.

It will be understood by those skilled in the art that the singular forms "a", "an", "the" and "the" as used herein can include the plural forms as well, unless expressly stated otherwise. It should be further understood that the word "comprising" used in the specification of this application refers to the presence of the stated features, integers, steps, operations, elements and/or components, but does not preclude the presence or addition of one or more other features, Integers, steps, operations, elements, components and/or groups thereof. It should be understood that the term "and/or" as used herein includes all or any element and all combinations of one or more of the associated listed items.

It will be understood by those skilled in 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 should also be understood that terms, such as those defined in a general dictionary, should be understood to have meanings consistent with their meanings in the context of the prior art and, unless specifically defined as herein, should not be interpreted in idealistic or overly formal meaning to explain.

The applicant found that, in the current ON Array solution of the fingerprint identification sensor, since the fingerprint identification sensor is arranged below the black matrix and the current conventional backlight is a surface light source, the fingerprint identification sensor is easily saturated after receiving the light from the backlight, and cannot perform fingerprinting. identify.

In view of this, the embodiment of the present application provides a new backlight module, so that in the fingerprint identification stage, the light emitted by the backlight is no longer a surface light source, so that the light from the backlight received by the fingerprint identification sensor is reduced, so that the fingerprint identification sensor can Perform fingerprint identification.

The backlight module provided by the embodiments of the present application will be described in detail below with reference to the accompanying drawings.

In the first aspect, FIG. 1 shows a backlight module 1 according to an embodiment of the present application. As shown in FIG. 1 , the backlight module 1 includes: a light guide plate 2 , an inverse prism 3 and a privacy film 4 . The inverse prism 3 is located on the light emitting surface of the light guide plate 2 and is used to aggregate the light emitted by the light guide plate 2 to form aggregated light. The anti-peep film 4 is located on the side of the inverse prism 3 away from the light guide plate 2, and is used to block the aggregated light at a certain angle to form collimated outgoing light.

Because the backlight module 1 of the embodiment of the present application includes an inverse prism 3 and a privacy film 4, wherein the inverse prism 3 is located on the light-emitting surface of the light guide plate 2, and is used to aggregate the light emitted by the light guide plate 2 to form aggregated light, preventing privacy The film 4 is located on the side of the inverse prism 3 away from the light guide plate 2, and is used to block the aggregated light at a certain angle to form collimated outgoing light. Therefore, under the combined action of the reverse prism 3 and the anti-peep film 4 in the embodiment of the present application, the backlight module 1 can form collimated outgoing light. When the backlight module 1 in the embodiment of the present application is matched with the fingerprint identification sensor of ON Array In the solution, the collimated outgoing light makes the fingerprint identification sensor less likely to be saturated, and the fingerprint identification can be well realized, thereby enhancing the market competitiveness of the LCD display device.

Specifically, FIG. 2 shows a light ray routing diagram when the light 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 source 8 , wherein the frame 7 is used to fix the light guide plate 2 , the inverse prism 3 , and the privacy film. 4 and the reflective layer 6 and the specific arrangement of the frame 7 are similar to those in the prior art, and will not be repeated here. A light-emitting source 8 is arranged between the light guide plate 2 and the frame 7 (that is, one side of the light-incident surface of the light guide plate 2 ). I won't go into details here. The reflective layer 6 is arranged on the side of the light guide plate 2 away from the inverse prism 3 , and is used for reflecting the light into the light guide plate 2 to improve the utilization rate of the light. In addition, the backlight module 1 further includes a light-shielding tape 71, and the light-shielding tape 71 is used to prevent light leakage.

As shown in FIG. 2, when the light-emitting source 8 is driven to emit light, the light emitted by the light-emitting source 8 enters the light guide plate 2 from the light incident surface of the light guide plate 2, and the surface of the light guide plate 2 undergoes special microstructure treatment to make the light emitted from the light guide plate 2. The angle between the incident light and the horizontal is kept at about 15 degrees, and the light exit angle is controlled within the range of 10 degrees. Compared with the structure in which the backlight module adopts a double-layer prism in the prior art, the inverse prism 3 in the embodiment of the present application can improve the brightness of the backlight module by shrinking the beam angles in the vertical direction and the horizontal direction.

FIG. 3 shows the specific structure of the privacy protection film 4 . As shown in FIG. 3 , the anti-peep film 4 includes two spacer layers 41 and a plurality of anti-peep parts 42 arranged oppositely. The privacy guards 42 are disposed between the spacer layers 41 , and there is a certain distance between two adjacent privacy guards 42 . When the aggregated light passes through the privacy protection film 4, the privacy protection member 42 of the privacy protection film 4 can block the aggregated light at a certain angle to form collimated outgoing light. The privacy film commonly used in the prior art can be used, and there is no difficulty in setting.

The function of the inverse prism 3 in the embodiment of the present application is mainly to aggregate the light in the horizontal and vertical directions to improve the brightness of the light. The function of the anti-peep film 4 is to block the light of a specific angle. The collimated light that meets the brightness specification is formed under the combined action of the film 4 .

Since the anti-peeping film 4 is arranged on the reverse prism 3, the anti-peeping film 4 will block non-vertical light when in use, narrow the user's viewing angle, and cause inconvenience during use. In order to overcome the above problems, 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 viewing angle switching film 5 is located on the side of the anti-peeping film 4 away from the inverse prism 3, and the driving circuit 9 is used to output a driving electrical signal for the viewing angle switching film 5, so that the outgoing light is scattered after passing through the viewing angle switching film 5, or the outgoing light passes through the viewing angle. The propagation direction does not change after switching the membrane 5 . By setting the viewing angle switching film 5, the driving circuit 9 outputs different driving electrical signals according to actual needs (for example, when the driving electrical signal is a low-level signal, the emitted light can be scattered after passing through the viewing angle switching film 5; the driving electrical signal When it is a high-level signal, the outgoing light can pass through the viewing angle switching film 5 and the propagation direction remains unchanged), thereby changing the transmittance and haze of the viewing angle switching film 5, which can be suitable for the user's normal use requirements.

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 of the viewing angle switching film 5 . Table 1 shows that when the driving circuit outputs a low level and a high level to the viewing angle switching film 5 , the viewing angle switching film 5 has two different states. Specific parameters of light transmittance and haze. When the driving circuit outputs a low level (0V), the outgoing light is scattered after passing through the viewing angle switching film 5. At this time, the state of the viewing angle switching film 5 corresponds to the normal display stage. The wide viewing angle screen can make the display device display information normally, which is convenient for users. read. When the driving circuit outputs a high level (12V), the outgoing light passes through the viewing angle switching film 5 and the propagation direction remains unchanged. At this time, the viewing angle switching film 5 is in a privacy-proof state, and the privacy-proof state corresponds to the fingerprint recognition stage, and the viewing angle is narrowed at this time. , the light vertically passes through the viewing angle switching film 5 for fingerprint identification.

Table 1

Optical parameters low level high level Transmittance(%) 91±1 88±1 Haze (%) 74±1 3.0±0.5

Considering the influence of the fingerprint recognition sensor on the brightness of the backlight module 1, when the viewing angle switching film 5 is in a non-private state, it is found that the viewing angle switching film 5 cannot provide a brightness range that meets the user's requirements when it receives a low level. At this time, it is necessary to set an intermediate stage between the normal display stage and the fingerprint identification stage. The intermediate stage is set according to the voltage of the driving circuit 9. The light transmittance of the viewing angle switching film 5 is also different when the voltage is different. The application embodiment needs to set an intermediate level between a low level and a high level that can meet the user's brightness requirements. Through experiments and repeated tests, Table 2 provides the transmittance parameter values of the viewing angle switching film 5 under different voltages. As shown in Table 2, under normal circumstances, the brightness accepted by most users is when the level voltage value is 3V and the transmittance is 58.6%. However, it should be noted that the selection of the intermediate level needs to be selected according to the different requirements of customers for brightness.

Table 2

Optionally, 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 that are stacked and disposed on the side of the privacy protection film 4 away from the reverse prism 3 . 53. The first conductive layer 51 and the second conductive layer 53 are used for receiving driving electrical signals. The functional layer 52 is used to scatter the outgoing light under the control of the first conductive layer 51 and the second conductive layer 53, or to make the propagation direction of the outgoing light unchanged. In actual design, the first conductive layer 51 and the second conductive layer 53 are electrically connected to the driving circuit 9, and the voltage output by 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 the output The outgoing light is scattered, or the propagation direction of the outgoing light is unchanged.

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 the liquid crystal molecules in the polymer dispersed liquid crystal layer, so that the liquid crystal molecules have different , so that the outgoing light can be scattered, or the propagation direction of the outgoing light can be kept unchanged.

Optionally, continue to refer to FIG. 4 , in order to isolate the first conductive layer 51 and the second conductive layer 53 from other coatings and ensure the normal use of the viewing angle switching film 5 , the viewing angle switching film 5 of the embodiment of the present application also further A first protective layer 54 and a second protective layer 55 are included. 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 away from the privacy protection film 4 .

In specific implementation, the first conductive layer 51 and the second conductive layer 53 in the embodiments of the present application are transparent conductive layers, and the first conductive layer 51 and the second conductive layer 53 can be made of the same material, for example: the first conductive layer 51 and the second conductive layer 53 The layer 51 and the second conductive layer 53 may use indium tin oxide (ITO), indium zinc oxide (IZO), or a mixed material of ITO and IZO. The first protective layer 54 and the second protective layer 55 can be made of insulating and light-transmitting materials, for example, the first protective layer 54 and the second protective layer 55 can be made of silicon oxide or silicon nitride.

Based on the same inventive concept, in the second aspect, FIGS. 5-7 respectively show the display module 10 according to 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 figure, the backlight module 1 The specific structure can refer to Figure 1). Of course, the display module 10 of the embodiment of the present application can recognize fingerprints, so as to enable 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 10 of the embodiment of the present application includes the backlight module 1 of the first aspect. Under the combined action of the inverse prism 3 and the anti-peep film 4, a collimated light for fingerprint identification is formed, which further improves the accuracy of fingerprint identification. degree, and enhance the competitiveness of LCD display devices in the market.

5-7 , the display module 10 includes a main board 14 , a fingerprint identification chip 15 and a touch display control chip 16 , and the fingerprint identification chip 15 and the touch display control chip 16 are both integrated on the chip on film 12 . The chip on film 12 is connected to the main board 14 through the flexible circuit board 17 . Since both the fingerprint identification chip 15 and the touch display control chip 16 in the embodiment of the present application are integrated on the chip-on-film 12, the complexity of manufacturing the display module 10 is greatly simplified, and the possibility of mass production of the display module 10 is realized, and It can meet the needs of the narrow frame of the module. In addition, the fingerprint identification chip 15 and the touch display control chip 16 can be integrated into one IC (Integrated Circuit Chip) subsequently.

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

The fingerprint recognition principle of the display module 10 according to the embodiment of the present application will be described in detail below with reference to FIGS. 6 to 8 :

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

In order to facilitate understanding, it is first necessary to explain the Chinese names of the English abbreviations in FIGS. 6 to 8 and their uses. In Figures 6 and 7,

SPI is a serial communication interface (Serial Peripheral Interface), which is used to transmit fingerprint images and finger point coordinates.

AFE is an analog front end interface (Analog Front End), which is used to accept the analog signals output by the fingerprint recognition sensor and the touch sensor.

I2C is an I2C serial communication interface used to transmit finger point coordinates.

MIPI is a Mobile Industry Processor Interface, which is used to transmit display image information.

AC is an AC circuit unit, which is used to receive and output suitable AC signals.

TC, after the fingerprint identification chip 15 confirms the identification area according to the finger coordinates, it outputs a corresponding area selection signal.

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

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

Sensor Gate1...Sensor GateN are the switch signals of the fingerprint recognition sensors in the first row to the Nth row.

LFD is a Loading Free Driver, which is used to make the power signal of the display and fingerprint not affect the touch operation during touch.

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

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

In the embodiment shown in FIG. 6 , when the user's finger touches the liquid crystal display panel 11 , the touch detection unit 18 detects the finger, generates a touch analog signal of the coordinates of the finger, and sends the touch analog signal to the touch analog signal. The touch display control chip 16 converts the touch analog signal of the finger point coordinates into the touch digital signal of the finger point coordinates, and transmits the touch digital signal of the finger point coordinates to the touch display control chip 16 through the AFE. The main board 14, the main board 14 determines that the liquid crystal display panel 11 is touched according to the touch digital signal, and transmits the display signal to the touch display control chip 16 through MIPI, and the touch display control chip 16 outputs a display drive signal to drive the liquid crystal display panel 11 to display fingerprints Identify the desktop (ie, a picture showing a specific fingerprint recognition area).

At the same time, as shown in FIG. 6 , the fingerprint recognition chip 15 sends out the driving signal of the fingerprint recognition sensor in the corresponding area according to the finger coordinate signal sent by the main board 14 through the SPI. After the fingerprint recognition sensor 13 detects the user's fingerprint, the fingerprint The fingerprint analog signal of the 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 mainboard 14 performs a fingerprint recognition algorithm on the fingerprint digital signal, and compares the obtained fingerprint image with the image pre-stored in the mainboard 14. When the screen driving information is generated and transmitted to the touch display control chip 16 via MIPI, the touch display is finally performed. The control chip 16 is transmitted to the liquid crystal display panel 11 to drive the liquid crystal display panel 11 to display normally.

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 shown in FIG. 6 , and details are not repeated here. The difference is that the backlight module 1 at this time is provided with a 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 by the touch display control chip 16 to the screen. The main board 14 , according to the brightness information, the main board 14 outputs the corresponding AC signal to the driving circuit 9 through the AC circuit unit in the main board 14 , so that the viewing angle switching film 5 can freely switch the transmittance.

Based on the same inventive concept, in a third aspect, an embodiment of the present application discloses a display device, including 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 beneficial effects of the display device of the third aspect will not be repeated.

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

S101 : Receive a reset electrical signal, and reset the fingerprint identification sensor 13 .

S102 : The fingerprint identification sensor 13 receives the collimated outgoing light to collect the fingerprint information input in the 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 sends it to the motherboard 14 .

S103: The motherboard 14 compares the processed fingerprint information with the preset fingerprint information, and when it is determined that the two are the same, outputs a display signal to the touch display control chip 16 to control the liquid crystal display panel 11 to display normally.

It should be noted that the fingerprint information collected by the fingerprint identification sensor 13 includes a fingerprint image, and the fingerprint image is sent to the fingerprint identification chip 15 in the form of an analog signal. The fingerprint identification chip 15 processes the fingerprint image analog signal, and forms a fingerprint image after processing. digital signal, and transmit 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 refers to the normal display of information by the liquid crystal display panel 11 , as shown in FIG. 8 , the normal display here refers to the display in the normal use state. In the actual working process, there is also a display frame in the fingerprint identification state, and the picture of the specific fingerprint identification area is displayed in the display frame.

Specifically, the fingerprint recognition sensor 13 receives the collimated outgoing light to collect the fingerprint information input in the fingerprint recognition area, including: the collimated backlight outgoing light passes through the liquid crystal display module, and finally passes through the glass cover to reach the finger and the glass. At the interface, due to the fixed direction, the interference of stray light is small, and the fingerprint recognition sensor 13 will not be saturated. The collimated light is reflected by the finger, passes through the glass cover plate and the liquid crystal display module again, and is captured by the fingerprint identification sensor 13. Due to the different reflected light from the peaks and valleys of the fingerprint, the fingerprint identification sensor 13 receives different light irradiation, and realizes the energy of photoelectric conversion. If there are differences, the collection of fingerprint information can be completed.

In the embodiment of the present application, more accurate fingerprint coordinate information is obtained by collimating light, so that when the motherboard 14 performs fingerprint comparison, the comparison result is more accurate and fast; and the fingerprint identification method in the embodiment of the present application is used in an LCD display device , increasing the market competitiveness of LCD display devices.

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

The driving circuit outputs a high-level signal, so that the propagation direction of the outgoing light remains unchanged after passing through the viewing angle switching film 5, so that the fingerprint identification sensor 13 receives the collimated outgoing light;

When determined to be the same, also include:

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

FIG. 10 shows the 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 VGAate, the first terminal is connected to the first terminal of the second thin film transistor T2 , and the second terminal is connected to the current output terminal I_OUT. The control terminal of the second thin film transistor T2 is respectively connected to the first terminal of the third thin film transistor T3, the light emitting device and one terminal of the capacitor, 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 connect. 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 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 will be in the reset stage, the acquisition stage and the reading stage, among which

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.

Acquisition stage: pull down the voltage reset terminal, that is, the voltage reset terminal VRST outputs a low-level signal, the third thin film transistor T3 is turned off, the fingerprint recognition sensor receives the collimated outgoing light, and the photoelectric signal is accumulated in the fingerprint recognition sensor circuit. Signal amplification is performed through the second thin film crystal T2 and the power supply terminal VDD.

Reading phase: After the acquisition phase, the voltage control terminal VGAate is pulled high, that is, the voltage control terminal VGAate outputs a high-level signal, thereby turning on the first thin film transistor T1, so that the fingerprint identification chip 15 can read the signal of the current output terminal I_OUT.

The beneficial effects obtained by applying the embodiments of the present application include:

1. Since the backlight module 1 of the embodiment of the present application includes an inverse prism 3 and an anti-peeping film 4, wherein the inverse prism 3 is located on the light-emitting surface of the light guide plate 2, and is used to aggregate the light emitted by the light guide plate 2 to form aggregated light, The anti-peep film 4 is located on the side of the inverse prism 3 away from the light guide plate 2, and is used to block the aggregated light at a certain angle to form collimated outgoing light. Therefore, under the combined action of the reverse prism 3 and the anti-peep film 4 in the embodiment of the present application, the backlight module 1 can form collimated outgoing light. When the backlight module 1 in the embodiment of the present application is matched with the fingerprint identification sensor of ON Array In the solution, the collimated outgoing light makes the fingerprint identification sensor less likely to be saturated, and the fingerprint identification can be well realized, thereby enhancing the market competitiveness of the LCD display device.

2. Since the backlight module 1 of the embodiment of the present application includes the inverse prism 3, compared with the structure of the double-layer prism used in the backlight module of the prior art, the inverse prism 3 in the embodiment of the present application can shrink the vertical direction and the horizontal direction by shrinking. The beam angle increases the brightness of the backlight module.

3. Since the backlight module 1 of the embodiment of the present application is also provided with a viewing angle switching film 5 on the side of the privacy protection film 4 away from the inverse prism 3, through the viewing angle switching film 5, according to the level of the voltage output by the driving circuit 9, Thus, the transmittance and haze of the viewing angle switching film 5 can be changed, which can be adapted to the requirements of the user for normal use.

4. As in the embodiment of the present application, the fingerprint identification chip 15 and the touch display control chip 16 are both integrated on the chip-on-film 12, which greatly simplifies the complexity of manufacturing the display module 10 and realizes the possibility of mass production of the display module 10. and can meet the needs of the narrow frame of the module.

Those skilled in the art can understand that various operations, methods, steps, measures, and solutions in the process discussed in this application may be alternated, modified, combined or deleted. Further, other steps, measures, and solutions in the various operations, methods, and processes that have been discussed in this application may also be alternated, modified, rearranged, decomposed, combined, or deleted. Further, steps, measures and solutions in the prior art with various operations, methods, and processes disclosed in this application may also be alternated, modified, rearranged, decomposed, combined or deleted.

In the description of this application, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", The orientation or positional relationship indicated by "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying The device or element referred to must have a particular orientation, be constructed and operate in a particular orientation, and therefore should not be construed as a limitation of the present application.

The terms "first" and "second" are only used for descriptive purposes, and should not 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 expressly or implicitly include one or more of that feature. In the description of this application, unless stated otherwise, "plurality" means two or more.

It should be understood that although the various steps in the flowchart of the accompanying drawings are sequentially shown in the order indicated by the arrows, these steps are not necessarily executed in sequence in the order indicated by the arrows. Unless explicitly stated herein, the execution of these steps is not strictly limited to the order and may be performed in other orders. Moreover, at least a part of the steps in the flowchart of the accompanying drawings may include multiple sub-steps or multiple stages, and these sub-steps or stages are not necessarily executed at the same time, but may be executed at different times, and the execution sequence is also It does not have to be performed sequentially, but may be performed alternately or alternately with other steps or at least a portion of sub-steps or stages of other steps.

The above are only part of the embodiments of the present application. It should be pointed out that for those skilled in the art, without departing from the principles of the present application, several improvements and modifications can also be made. It should be regarded as the protection scope of this application.

Claims (10)

1. A backlight module, comprising: a light guide plate, a reverse prism and a peep-proof 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.

2. The backlight module according to claim 1, further comprising 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 propagation direction is unchangeable behind the visual angle switching film.

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

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

and 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 conductive layer and the second conductive layer.

4. The backlight module according to claim 3, wherein 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.

5. A display module, comprising: a liquid crystal display panel, a flip-chip, and the backlight module of any one of claims 1-4;

the liquid crystal display panel comprises a fingerprint identification sensor.

6. The display module according to claim 5, 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;

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

7. The display module assembly of claim 6, 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.

8. A display device, comprising the display module according to any one of claims 5 to 7.

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

receiving a reset electric 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.

10. The fingerprint identification method according to claim 9, 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 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.

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