Fingerprint identification device, backlight unit, display screen and electronic equipment
阅读说明:本技术 指纹识别装置、背光模组、显示屏和电子设备 (Fingerprint identification device, backlight unit, display screen and electronic equipment ) 是由 青小刚 李顺展 于 2019-12-24 设计创作,主要内容包括:提供了一种指纹识别装置、背光模组,显示屏和电子设备,所述指纹识别装置应用于具有液晶显示LCD屏的电子设备,所述LCD屏包括背光模组,所述指纹识别装置包括:指纹识别模组,所述指纹识别模组用于设置在所述背光模组的下方,所述指纹识别模组用于接收红外光源发出的照射人体手指后返回的并穿过所述背光模组的红外光信号以获取所述人体手指的指纹图像;其中,所述背光模组包括导光板和反射膜,所述导光板设置在所述反射膜的上方,所述导光板与所述指纹识别模组相对的下表面设置有凹槽,所述指纹识别模组用于设置在所述凹槽的下方。(The utility model provides a fingerprint identification device, backlight unit, display screen and electronic equipment, the electronic equipment that has liquid crystal display LCD screen is applied to the fingerprint identification device, the LCD screen includes backlight unit, the fingerprint identification device includes: the fingerprint identification module is arranged below the backlight module and used for receiving an infrared light signal which is emitted by an infrared light source, irradiates a human finger and returns back and passes through the backlight module so as to acquire a fingerprint image of the human finger; the backlight module comprises a light guide plate and a reflecting film, the light guide plate is arranged above the reflecting film, a groove is formed in the lower surface, opposite to the fingerprint identification module, of the light guide plate, and the fingerprint identification module is arranged below the groove.)
1. The utility model provides a fingerprint identification device which characterized in that is applied to the electronic equipment who has liquid crystal display LCD screen, the LCD screen includes backlight unit, fingerprint identification device includes:
the fingerprint identification module is arranged below the backlight module and used for receiving an infrared light signal which is emitted by an infrared light source, irradiates a human finger and returns back and passes through the backlight module so as to acquire a fingerprint image of the human finger;
the backlight module comprises a light guide plate and a reflecting film, the light guide plate is arranged above the reflecting film, a groove is formed in the lower surface, opposite to the fingerprint identification module, of the light guide plate, and the fingerprint identification module is arranged below the groove.
2. The fingerprint recognition device according to claim 1, wherein the depth of the groove is set such that a pitch between interference fringes in the fingerprint image is smaller than a pitch between fingerprint fringes of the human finger.
3. The fingerprint recognition device according to claim 1 or 2, wherein a vertical height from a bottom surface of the groove to an upper surface of the reflective film is greater than or equal to 20 μm.
4. The fingerprint identification device according to any one of claims 1 to 3, wherein a dimension of the groove in a direction parallel to the LCD screen is greater than or equal to a corresponding dimension of a field angle FOV of the fingerprint identification module on the light guide plate.
5. The fingerprint identification device of claim 1, wherein a dimension of the groove in a direction parallel to the LCD screen is greater than or equal to a dimension corresponding to a position of an FOV of the fingerprint identification module along an upper edge of the groove.
6. The fingerprint identification device according to claim 1, wherein the lower surface of the light guide plate is provided with light guide points, and the density of the light guide points in the groove region is different from the density of the light guide points in the surrounding region of the groove.
7. The fingerprint recognition device according to any one of claims 1 to 6, wherein the shape of the groove is circular or square.
8. The fingerprint recognition device according to any one of claims 1 to 7, wherein the backlight module further comprises a steel plate disposed below the reflective film, the steel plate having an opening formed therein, the fingerprint recognition module being configured to be disposed below the opening to receive the infrared light signal returned from the human finger and passing through the opening.
9. The fingerprint recognition device of claim 8, wherein the size of the opening is greater than or equal to the corresponding size of the FOV of the fingerprint recognition module on the steel plate, so that the infrared light signal returning from the human finger within the FOV range of the fingerprint recognition module can be received by the fingerprint recognition module.
10. The fingerprint identification device of claim 8 or 9, wherein the groove is formed in a middle region or a middle lower region of the light guide plate, so that the fingerprint detection region of the fingerprint identification module is located in a middle position or a middle lower position of the display region of the LCD screen.
11. The fingerprint recognition device according to any one of claims 1 to 10, wherein a light transmittance of the infrared light signal on the reflective film is larger than a light transmittance of a light signal for image display of an LCD screen on the reflective film.
12. The fingerprint recognition device according to any one of claims 1 to 11, wherein the reflectance of the infrared light signal on the reflection film is smaller than the reflectance of the light signal on the reflection film for image display of an LCD panel.
13. The fingerprint recognition device of any one of claims 1-12, wherein the fingerprint recognition module comprises:
a fingerprint sensor for receiving the infrared light signal to be returned from the human finger to acquire a fingerprint image of the human finger;
an optical component disposed above the sensor pixel for guiding the infrared light signal returned from the human finger to the sensor pixel for optical fingerprint detection.
14. A backlight module is characterized by comprising a light guide plate and a reflecting film, wherein the light guide plate is arranged above the reflecting film, a groove is formed in the lower surface of the light guide plate, and a fingerprint identification module is arranged below the groove to realize optical fingerprint detection under a screen;
the infrared light signal sent by the infrared light source and returned after irradiating the human finger penetrates through the backlight module to be transmitted to the fingerprint identification module, and the infrared light signal is used for acquiring a fingerprint image of the human finger.
15. The backlight module according to claim 14, wherein the depth of the groove is set such that the distance between the interference fringes in the fingerprint image is smaller than the distance between the fingerprint fringes of the human finger.
16. A backlight module according to claim 14 or 15, wherein the vertical height from the bottom surface of the groove to the upper surface of the reflective film is greater than or equal to 20 μm.
17. The backlight module according to any one of claims 14 to 16, wherein a dimension of the groove in a direction parallel to the LCD screen is greater than or equal to a corresponding dimension of a field angle FOV of the fingerprint identification module on the light guide plate.
18. The backlight module according to claim 17, wherein the dimension of the groove in the direction parallel to the LCD screen is greater than or equal to the dimension corresponding to the position of the FOV of the fingerprint identification module along the upper edge of the groove.
19. A backlight module according to any one of claims 14-18, wherein the lower surface of the light guide plate is provided with light guide dots, and the density of the light guide dots in the groove region is different from the density of the light guide dots in the surrounding region of the groove.
20. A backlight module according to any one of claims 14-19, wherein the grooves are circular or square in shape.
21. The backlight module according to any one of claims 14-20, further comprising a steel plate disposed below the reflective film, wherein the steel plate has an opening formed thereon, and the fingerprint recognition module is disposed below the opening to receive the infrared light signal returned from the human finger and passing through the opening.
22. The backlight module according to claim 21, wherein the size of the opening is greater than or equal to the corresponding size of the FOV of the fingerprint identification module on the steel plate, so that the infrared light signal returning from the human finger within the FOV of the fingerprint identification module can be received by the fingerprint identification module.
23. The backlight module according to claim 21 or 22, wherein the groove is formed in a middle region or a middle lower region of the light guide plate, so that the fingerprint detection region of the fingerprint identification module is located at a middle position or a middle lower position of the display region of the LCD panel.
24. An electronic device, comprising:
a liquid crystal panel;
the backlight module is used for providing a backlight source for the liquid crystal panel and comprises a light guide plate and a reflecting film, the light guide plate is arranged above the reflecting film, and a groove is formed in the lower surface of the light guide plate;
the fingerprint identification device according to any one of claims 1 to 13, comprising a fingerprint identification module, wherein the fingerprint identification module is disposed below the groove, and configured to receive an infrared light signal emitted by an infrared light source and returned after illuminating a human finger and passing through the backlight module to obtain a fingerprint image of the human finger.
25. A display screen, comprising:
a backlight module according to any of claims 14 to 23.
26. An electronic device, comprising: a display screen as recited in claim 25.
Technical Field
The embodiment of the application relates to the field of fingerprint identification under a screen, and more particularly relates to a fingerprint identification device, a backlight module, a display screen and an electronic device.
Background
Currently, a Liquid Crystal Display (LCD) screen includes a backlight module and a Liquid Crystal panel, wherein the backlight module provides a uniform light source for the screen, and the Liquid Crystal panel plays a role in displaying images. Optical fingerprint identification scheme is in order to realize optical fingerprint identification with fingerprint identification module setting in backlight unit's below based on the screen of LCD, and wherein, backlight unit is multilayer membrane material structure, and the inhomogeneous problem of contact appears easily in deformation between the membrane material, leads to producing the forming condition who disturbs line (film interference), and like this, the fingerprint image of gathering at fingerprint identification module can have the interference line, influences the fingerprint identification performance.
Therefore, how to eliminate or reduce interference patterns to improve the performance of optical fingerprint recognition under LCD screens is an urgent problem to be solved.
Disclosure of Invention
The utility model provides a fingerprint identification device, backlight unit, display screen and electronic equipment can eliminate or reduce the interference line to optical fingerprint identification's performance under the LCD screen is promoted.
In a first aspect, a fingerprint identification device is provided for an electronic device having a Liquid Crystal Display (LCD) screen, the LCD screen includes a backlight module, the fingerprint identification device includes:
the fingerprint identification module is arranged below the backlight module and used for receiving an infrared light signal which is emitted by an infrared light source, irradiates a human finger and returns back and passes through the backlight module so as to acquire a fingerprint image of the human finger;
the backlight module comprises a light guide plate and a reflecting sheet, the light guide plate is arranged above the reflecting sheet, a groove is formed in the lower surface, opposite to the fingerprint identification module, of the light guide plate, and the fingerprint identification module is arranged below the groove.
In some possible implementation manners, the groove formed in the lower surface of the light guide plate is used for increasing a distance between the light guide plate and the reflector plate corresponding to the upper side of the fingerprint detection area of the fingerprint identification module.
In some possible implementations, the depth of the groove is set such that a spacing between interference fringes in the fingerprint image is smaller than a spacing between fingerprint streaks of the human finger.
In some possible implementations, a vertical height of a bottom surface of the groove to an upper surface of the reflective sheet is greater than or equal to 20 micrometers.
In some possible implementations, a dimension of the groove in a direction parallel to the LCD screen is greater than or equal to a corresponding dimension of a field angle FOV of the fingerprint identification module on the light guide plate.
In some possible implementations, a dimension of the groove in a direction parallel to the LCD screen is greater than or equal to a dimension corresponding to a position of an FOV of the fingerprint identification module along an upper edge of the groove.
In some possible implementations, the lower surface of the light guide plate is provided with light guide points, and the density of the light guide points in the groove region is different from the density of the light guide points in the peripheral region of the groove.
In some possible implementations, the shape of the groove is circular or square.
In some possible implementations, the backlight module further includes a steel plate disposed below the reflection sheet, an opening is formed in the steel plate, and the fingerprint identification module is disposed below the opening to receive the infrared light signal returned from the human finger and passing through the opening.
In some possible implementations, the size of the opening is greater than or equal to the corresponding size of the FOV of the fingerprint identification module on the steel plate, so that the infrared light signal returning from the human finger within the FOV of the fingerprint identification module can be received by the fingerprint identification module.
In some possible implementations, the groove is disposed in a middle region or a middle lower region of the light guide plate, so that the fingerprint detection region of the fingerprint identification module is located in a middle position or a middle lower position of the display region of the LCD screen.
In some possible implementation manners, the backlight module further includes a diffusion film and a brightness enhancement film disposed above the light guide plate, wherein an optical signal emitted by a light source for displaying an image of the LCD panel passes through the light guide plate and then is transmitted to the diffusion film, the optical signal diffused by the diffusion film is transmitted to the brightness enhancement film, and the incremental film is configured to enhance the received optical signal and transmit the enhanced optical signal to a display unit of the LCD panel for displaying the image.
In some possible implementations, a light transmittance of the infrared light signal on the reflective sheet is greater than a light transmittance of a light signal for image display of an LCD screen on the reflective sheet.
In some possible implementations, the reflectivity of the infrared light signal on the reflective sheet is less than the reflectivity of the light signal on the reflective sheet for image display of the LCD panel.
In some possible implementations, the fingerprint identification module includes:
a fingerprint sensor including a plurality of sensor pixels for receiving the infrared light signal to be returned from the human finger to acquire a fingerprint image of the human finger;
an optical component disposed above the sensor pixel for guiding the infrared light signal returned from the human finger to the sensor pixel for optical fingerprint detection.
In a second aspect, a backlight module is provided, which comprises a light guide plate and a reflector plate, wherein the light guide plate is arranged above the reflector plate, a groove is arranged on the lower surface of the light guide plate, and a fingerprint identification module is arranged below the groove to realize optical fingerprint detection under a screen; the infrared light signal sent by the infrared light source and returned after irradiating the human finger penetrates through the backlight module to be transmitted to the fingerprint identification module, and the infrared light signal is used for acquiring a fingerprint image of the human finger.
In some possible implementation manners, the groove formed in the lower surface of the light guide plate is used for increasing a distance between the light guide plate and the reflector plate corresponding to the upper side of the fingerprint detection area of the fingerprint identification module.
In some possible implementations, the depth of the groove is set such that a spacing between interference fringes in the fingerprint image is smaller than a spacing between fingerprint streaks of the human finger.
In some possible implementations, a vertical height of a bottom surface of the groove to an upper surface of the reflective sheet is greater than or equal to 20 micrometers.
In some possible implementations, a dimension of the groove in a direction parallel to the LCD screen is set to be greater than or equal to a corresponding dimension of a field angle FOV of the fingerprint identification module on the light guide plate.
In some possible implementations, a dimension of the groove in a direction parallel to the LCD screen is set to be greater than or equal to a dimension corresponding to a position of the FOV of the fingerprint identification module on the upper edge of the groove.
In some possible implementations, the lower surface of the light guide plate is provided with light guide points, and the density of the light guide points in the groove region is different from the density of the light guide points in the peripheral region of the groove.
In some possible implementations, the density of the light guide points of the groove region is set such that the brightness of the display screen corresponding to the groove region is equivalent to the brightness of the display screen corresponding to the surrounding region, so as to make the brightness of the entire LCD screen uniform.
In some possible implementations, the shape of the groove is circular or square.
In some possible implementations, the backlight module further includes a steel plate disposed below the reflection sheet, an opening is formed in the steel plate, and the fingerprint identification module is disposed below the opening to receive the infrared light signal returned from the human finger and passing through the opening.
In some possible implementations, the size of the opening is greater than or equal to the corresponding size of the FOV of the fingerprint identification module on the steel plate, so that the infrared light signal returning from the human finger within the FOV of the fingerprint identification module can be received by the fingerprint identification module.
In some possible implementations, the groove is disposed in a middle region or a middle lower region of the light guide plate, so that the fingerprint detection region of the fingerprint identification module is located in a middle position or a middle lower position of the display region of the LCD screen.
In some possible implementation manners, the backlight module further includes a diffusion film and a brightness enhancement film disposed above the light guide plate, wherein an optical signal emitted by a light source for displaying an image of the LCD panel passes through the light guide plate and then is transmitted to the diffusion film, the optical signal diffused by the diffusion film is transmitted to the brightness enhancement film, and the incremental film is configured to enhance the received optical signal and transmit the enhanced optical signal to a display unit of the LCD panel for displaying the image.
In some possible implementations, a light transmittance of the infrared light signal on the reflective sheet is greater than a light transmittance of a light signal for image display of an LCD screen on the reflective sheet.
In some possible implementations, the reflectivity of the infrared light signal on the reflective sheet is less than the reflectivity of the light signal on the reflective sheet for image display of the LCD panel.
In a third aspect, an electronic device is provided, including:
a liquid crystal panel;
the backlight module is used for providing a backlight source for the liquid crystal panel and comprises a light guide plate and a reflecting sheet, wherein the light guide plate is arranged above the reflecting sheet, and a groove is formed in the lower surface of the light guide plate;
the fingerprint identification device in the mode that any one of first aspect and first aspect probably realized, the fingerprint identification device includes the fingerprint identification module, wherein, the fingerprint identification module sets up in the below of recess for receive that infrared light source sends shine human finger back return and pass through the infrared light signal of backlight unit in order to acquire the fingerprint image of human finger.
In a fourth aspect, an electronic device is provided, comprising:
the backlight module described in any possible implementation manner of the second aspect and the second aspect.
Based on above technical scheme, can realize increasing the interval between light guide plate and the reflectance coating and then eliminate the purpose of the interference line between light guide plate and the reflectance coating through set up the recess at the lower surface of light guide plate, in concrete realization, only need change the light guide plate the mould can, need not change reflectance coating and other mounting structure, it is simple to realize, and is less to the whole influence of display screen.
Drawings
Fig. 1 is a schematic plan view of an electronic device to which the present application may be applied.
Fig. 2 is a schematic diagram of a typical structure of a backlight module.
Fig. 3 is a light path transmission diagram in the backlight module.
FIG. 4 is a diagram of the formation of interference patterns.
Fig. 5 is a typical structure view of a light guide plate.
Fig. 6 is a schematic diagram of the distribution of light guide points on the light guide plate.
Fig. 7 is a schematic view showing a relationship between a distance between the light guide plate and the reflective film and a distance between the interference patterns.
Fig. 8 is a schematic diagram of an application scenario of a fingerprint identification device according to an embodiment of the present application.
Fig. 9 is an oblique view of a light guide plate according to an embodiment of the present application.
Fig. 10 is a sectional view of a light guide plate according to an embodiment of the present application.
Fig. 11 to 13 are schematic diagrams of arrangement of infrared light sources according to an embodiment of the present application.
Fig. 14 is a schematic structural diagram of a backlight module according to an embodiment of the present application.
Fig. 15 is a schematic structural diagram of an electronic device according to an embodiment of the present application.
Fig. 16 is a schematic structural diagram of a display screen according to an embodiment of the present application.
Detailed Description
As the smart terminal moves into the full-screen era, the fingerprint acquisition area on the front side of the electronic device is squeezed by the full-screen, and therefore the Under-screen (or Under-screen) fingerprint identification technology is receiving more and more attention. Fingerprint identification technology is installed in the display screen below with fingerprint identification device (for example fingerprint identification module) under the screen to realize carrying out the fingerprint identification operation in the display area inside of display screen, need not set up the fingerprint collection region in the positive region except that the display area of electronic equipment.
The underscreen fingerprint identification technology may include underscreen optical fingerprint identification technology, underscreen ultrasonic fingerprint identification technology, or other types of underscreen fingerprint identification technology.
Taking the example of an off-screen optical fingerprinting technique, the off-screen optical fingerprinting technique uses light returning from the top surface of the device display assembly for fingerprint sensing and other sensing operations. The returning light carries information of an object (e.g., a finger) in contact with the top surface, and a specific optical sensor module located below the display screen is implemented by capturing and detecting the returning light. The design of the particular optical sensor module may be such that the desired optical imaging is achieved by appropriately configuring the optical elements used to capture and detect the returned light.
It should be understood that the technical solutions of the embodiments of the present application may be applied to various electronic devices, and more particularly, may be applied to an electronic device having a display screen. Such as a portable or mobile computing device, for example, a smart phone, a notebook computer, a tablet computer, a game device, etc., but the present application is not limited thereto.
It should also be understood that, the technical solution of the embodiment of the present application may perform other biometric identification besides fingerprint identification, for example, living body identification or palm print identification, and the embodiment of the present application is also not limited thereto.
It should be noted that, for convenience of description, like reference numerals denote like parts in the embodiments of the present application, and a detailed description of the like parts is omitted in different embodiments for the sake of brevity.
It should be understood that the thickness, length, width and other dimensions of the various components in the embodiments of the present application and the overall thickness, length, width and other dimensions of the fingerprint recognition device shown in the drawings are only illustrative and should not be construed as limiting the present application in any way.
Fig. 1 shows a schematic diagram of an electronic device to which embodiments of the present application may be applied.
As shown in fig. 1, the electronic device 10 includes a display screen 120 and an optical fingerprint device, wherein the optical fingerprint device is disposed in a partial area below the display screen 120, for example, below a middle area of the display screen. The optical fingerprint device comprises an optical fingerprint sensor, the optical fingerprint sensor comprises a sensing array with a plurality of optical sensing units, and the area where the sensing array is located or the sensing area is a fingerprint detection area 103 of the optical fingerprint device. As shown in fig. 1, the fingerprint detection area 103 is located in a display area of the display screen 120.
It should be appreciated that the area of the fingerprint sensing area 103 may be different from the area of the sensing array of the optical fingerprint device, for example, by optical path design such as lens imaging, reflective folded optical path design or other optical path design such as light converging or reflecting, the area of the fingerprint sensing area 103 of the optical fingerprint device may be larger than the area of the sensing array of the optical fingerprint device. In other alternative implementations, the fingerprint sensing area 103 of the optical fingerprint device may also be designed to substantially coincide with the area of the sensing array of the optical fingerprint device if optical path guidance is performed, for example, by light collimation.
Therefore, when the user needs to unlock the terminal device or perform other fingerprint verification, the user only needs to press a finger on the fingerprint detection area 103 of the display screen 120, so as to realize fingerprint input. Since fingerprint detection can be implemented in the screen, the electronic device 10 with the above structure does not need to reserve a special space on the front surface thereof to set a fingerprint key (such as a Home key), so that a full-screen scheme can be adopted, that is, the display area of the display screen 120 can be substantially extended to the front surface of the whole electronic device 10.
As an alternative implementation manner, the optical fingerprint device includes a light detection portion and an optical assembly, the light detection portion includes the sensing array and a reading circuit and other auxiliary circuits electrically connected to the sensing array, which can be fabricated on a chip (Die) through a semiconductor process, such as an optical imaging chip or an optical fingerprint sensor, the sensing array is specifically a Photo detector (Photo detector) array, which includes a plurality of Photo detectors distributed in an array, and the Photo detectors can be used as the optical sensing units as described above; the optical assembly may be disposed above the sensing array of the light detection portion, and may specifically include a Filter layer (Filter), a light guide layer or a light path guide structure, and other optical elements, where the Filter layer may be configured to Filter ambient light penetrating through the finger, and the light guide layer or the light path guide structure is mainly configured to guide reflected light reflected from the surface of the finger to the sensing array for optical detection.
In a specific implementation, the optical assembly may be packaged in the same optical fingerprint device as the light detection portion. For example, the optical component may be packaged in the same optical fingerprint chip as the optical detection portion, or the optical component may be disposed outside the chip where the optical detection portion 134 is located, for example, the optical component is attached above the chip, or some components of the optical component are integrated in the chip.
In other embodiments, the optical fingerprint device uses an external light source to provide an optical signal for fingerprint detection, and the optical fingerprint device is suitable for a non-self-luminous display screen, such as a liquid crystal display screen or other passive luminous display screens. Taking an application to a liquid crystal display screen having a backlight module and a liquid crystal panel as an example, to support the underscreen fingerprint detection of the liquid crystal display screen, the optical fingerprint system of the electronic device 10 may further include an excitation light source for optical fingerprint detection, where the excitation light source may specifically be an infrared light source or a light source of non-visible light with a specific wavelength, and may be disposed below the backlight module of the liquid crystal display screen or in an edge area below a protective cover of the electronic device 10, and the optical fingerprint device may be disposed below the edge area of the liquid crystal panel or the protective cover and guided through a light path so that the fingerprint detection light may reach the optical fingerprint device; alternatively, the optical fingerprint device may be disposed below the backlight module, and the backlight module may be perforated or otherwise optically designed to allow the fingerprint detection light to pass through the liquid crystal panel and the backlight module and reach the optical fingerprint device by performing perforation or other optical designs on film layers such as a diffusion sheet, a brightness enhancement sheet, a reflection sheet, and the like.
It should be appreciated that in particular implementations, the electronic device 10 also includes a transparent protective cover positioned over the display screen 120 and covering the front of the electronic device 10. Because, in the present embodiment, the pressing of the finger on the display screen 120 actually means pressing on the cover plate above the display screen 120 or the surface of the protective layer covering the cover plate.
As shown in fig. 2, the LCD screen includes a backlight module 20 and a
The backlight module 20 sequentially includes from bottom to top: the light guide plate comprises a steel plate 26, a reflecting
Fig. 3 shows optical path transmission in each layer structure of the backlight module.
First, the light source 40 for image display emits a light signal, for example, white light, which enters the
the light signal transmitted in the
the light signal transmitted upward through the
the light signal transmitted upwards from the diffusion film 23 is transmitted to the brightness enhancement film 22, and the light-emitting angle is adjusted after passing through the brightness enhancement film 22, so that the intensity of the light signal emitted from the front surface is enhanced, and the brightness of the whole display screen is uniform.
Light guide plate among backlight unit adopts mould injection moulding's mode preparation usually, therefore, it is thicker for other rete thickness, the thickness of
The area of the steel plate 26 corresponding to the
Fig. 5 is a schematic view of a typical structure of the
In order to achieve uniform light emission on the whole display screen, the light guide points are distributed differently in different regions, for example, the light guide points in the region close to the light source for image display are sparse, and the light guide points in the region far from the light source are dense, as shown in fig. 6. Because
The embodiment of the application provides a technical scheme, through the structure of the light guide plate among the change backlight unit for interval increase between light guide plate and the reflectance coating makes the density increase of the interference line that forms between light guide plate and the reflectance coating, thereby can not form an image on the fingerprint identification module, that is to say, makes the sensor pixel in the fingerprint identification module can not catch this interference line, just also can reduce the influence to the fingerprint formation of image. Or the density of the interference grains is different from the grains of the fingerprint image, so that the interference grains can be further filtered in a filtering mode, and the influence on the fingerprint image can be reduced.
The interval between backlight unit's the membrane material and the interval of interference line have certain relation between, and technical scheme in the embodiment of this application is based on this relation design, for example, fig. 7 has illustrated this relation, and this relation obtains according to a fingerprint identification module's sampling data, and different fingerprint identification modules have certain difference, but the trend of the relation between the two is similar.
Figure 7 is shown including three groups of data, and the interval h that corresponds respectively between light guide plate and the reflectance coating is 2um, 4um, 10um, and the abscissa is the number of interference line, and the ordinate is the chip radius, and the dotted line shows the number of interference line that the chip radius is 1mm within range in figure 7, for example, when interval h is 4um, the chip radius is 1mm within range interference line and is 3, when interval h is 10um, the chip radius is 8 for 1mm within range interference line.
Therefore, the larger the distance between the visible film materials is, the more the number of the interference grains in the unit area is, namely the higher the density of the interference grains is, the smaller the interval of the interference grains is, the denser the image formed on the fingerprint sensor chip is, and under some conditions, when the distance between the interference grains is smaller than the distance between the fingerprint grains, the fingerprint sensor chip cannot capture the interference grains, and the interference on fingerprint imaging cannot be caused.
Fig. 8 is a schematic diagram of an application scenario of a fingerprint recognition device according to an embodiment of the present application.
This fingerprint identification device can be applied to the electronic equipment that has the LCD screen, the LCD screen includes backlight unit 4 and liquid
the
the backlight module 4 includes a
It should be understood that, in the embodiment of the present application, the fingerprint identification device may include an excitation light source for optical fingerprint detection, the excitation light source may be specifically the infrared
Optionally, in some embodiments of the present application, the backlight module 4 may further include a backlight light source for image display, and the backlight light source may use a visible light source, that is, a light signal for image display of the LCD screen is visible light, and specifically, the visible light source may be any light source located behind a Liquid Crystal Display (LCD). For example, the visible light source may be an Electroluminescent (EL) backlight, a compact Cold Cathode Fluorescent Lamp (CCFL), or an LED backlight.
In some embodiments of the present application, the transmittance of the infrared light signal on the reflective film is greater than the transmittance of the light signal on the reflective film for image display of the LCD panel.
In some embodiments of the present application, the reflectivity of the infrared light signal on the reflective film is less than the reflectivity of the light signal on the reflective film for image display of an LCD panel.
For example, the transmittance of the infrared light signal for fingerprint detection on the reflective film is greater than 90%, and the reflectance thereof is lower than 10%, so that the most sufficient light signal is further received by the fingerprint identification module through the reflective film. The light transmittance of the optical signal for image display on the reflecting film is lower than 10%, and the reflectivity is higher than 90%, so that the utilization rate of the optical signal emitted by the backlight light source is improved.
Therefore, in the embodiment of the present application, the optical signal for fingerprint detection uses an infrared light signal emitted from the infrared
It should be understood that, in the embodiment of the present application, the infrared light signal received by the
It should be understood that the fingerprint identification device may correspond to the optical fingerprint device in fig. 1, and the specific implementation thereof refers to the related description of the optical fingerprint device in fig. 1, and for brevity, the description is omitted here.
Optionally, in some embodiments of the present application, the
a fingerprint sensor including a plurality of sensor pixels for receiving the infrared light signal to be returned from the human finger to acquire a fingerprint image of the human finger;
an optical component disposed above the plurality of sensor pixels for guiding the infrared light signal returned from the human finger to the plurality of sensor pixels for optical fingerprint detection.
The fingerprint sensor may correspond to the light detection portion in the embodiment shown in fig. 1, and the optical component may correspond to the optical component in the embodiment shown in fig. 1, and for specific implementation, reference may be made to relevant descriptions in the embodiment shown in fig. 1, and for brevity, details are not described here again.
It should be understood that in the embodiments of the present application, the sensor pixels may also be referred to as sensing units, optical sensing units, etc., and information collected by one sensor pixel may be used to form one pixel in a fingerprint image.
In the embodiment of the present application, the
In the embodiment of the present application, the
Through the lower surface at
Therefore, in this application embodiment, set up the recess through the lower surface at the light guide plate and can realize increasing the interval between light guide plate and the reflectance coating and then eliminate the purpose of the interference line between light guide plate and the reflectance coating, in concrete realization, only need change the light guide plate the mould can, need not change reflectance coating and other mounting structure, it is simple to realize, and is less to the whole influence of display screen.
In some designs, the depth of the
That is, the depth of the groove is set to make the interference fringes in the fingerprint image have a significant difference from the fingerprint pattern, for example, the distance between the interference fringes in the fingerprint image is significantly greater or significantly less than the distance between the fingerprint fringes, and further, the interference fringes are filtered out by software.
Preferably, the depth of the grooves is set such that the spacing between interference fringes in the fingerprint image is smaller than the spacing between fingerprint ridges.
Taking the data illustrated in fig. 7 as an example, assuming that the distance between the fingerprint ridges is 0.2mm, when the distance h between the
In some embodiments, a vertical height from the bottom surface of the groove to the upper surface of the reflective film may be set according to a size of a sensor pixel of the fingerprint sensor and a relationship between a distance between the light guide plate and the reflective film and a distance between the interference fringes, for example, in this embodiment, according to a current size of the fingerprint sensor pixel, a vertical height from the bottom surface of the groove to the upper surface of the reflective film is greater than or equal to 20 micrometers, so that a distance between the interference fringes in a fingerprint image acquired by the fingerprint identification module is smaller than a distance between fingerprint grains of a human finger.
In some embodiments, the dimension Of the
Preferably, the dimension of the
It should be understood that the FOV of the fingerprint identification module may correspond to a corresponding dimension in each layer of the backlight module, the corresponding dimension in each layer of the backlight module decreases from top to bottom, and the dimension S in fig. 10 is an example of a corresponding dimension of the FOV of the fingerprint identification module in the
In a specific implementation, the size of the groove in the direction parallel to the LCD screen is set to be greater than or equal to the size corresponding to the position of the FOV of the fingerprint identification module on the upper edge of the groove, that is, the size of the bottom surface of the groove is greater than or equal to the size corresponding to the position of the FOV of the fingerprint identification module on the bottom of the groove.
Preferably, the size of the bottom surface of the
In the embodiment of the present invention, as shown in fig. 9, the light guide plate may include a substrate 443 and two layers of microstructures on the upper and lower surfaces of the substrate, where the upper surface is a
In the embodiment, the substrate 443 may be made of a high-tech material with very high reflectivity and no light absorption, such as an optical-grade acrylic plate, and the light guide points 441 may be formed on the
Specifically, the backlight source for image display may be disposed at a side of the
Optionally, in some embodiments of the present application, various light guide points with different densities and sizes may be utilized to make the
Since the
In a specific implementation, the density of the light guide points of the groove region is set to make the brightness of the display screen corresponding to the groove region equivalent to the brightness of the display screen corresponding to the surrounding region, so that the brightness of the whole LCD screen is uniform.
In some embodiments, if the brightness of the display screen corresponding to the groove region is higher than the brightness of the display screen corresponding to the peripheral region of the groove, the density of the light guide points of the groove region may be reduced, or if the brightness of the display screen corresponding to the groove region is lower than the brightness of the display screen corresponding to the peripheral region of the groove, the density of the light guide points of the groove region may be increased, so that the brightness of the entire display screen is uniform.
The fact that the brightness of the display screen corresponding to the groove region is equal to the brightness of the display screen corresponding to the peripheral region means that the brightness of the display screen corresponding to the groove region is the same as or similar to the brightness of the display screen corresponding to the peripheral region of the groove, or the brightness of the display screen corresponding to the peripheral region of the groove is at the same level.
Optionally, in some embodiments, the shape of the groove is a circle or a square, or may be other shapes, which is not limited in this application.
In the embodiment of the present application, the backlight module 4 further includes a steel plate 46 disposed below the
Through form on the steel sheet 26 trompil 261, can prevent as far as possible that visible light signal is to the opposite direction transmission with the LCD screen to avoid backlight unit 4 causes the damage because of external impact, can effectively reduce the infrared light signal that is used for fingerprint identification moreover and pass through the energy loss when steel sheet 46.
In some embodiments, the size of the opening is greater than or equal to the size of the FOV of the
In some embodiments, the size of the aperture is smaller than the size of the recess.
In this application embodiment, the recess is seted up the middle zone or the middle part of light guide plate are regional down, so that the fingerprint detection area of fingerprint identification module is located the intermediate position or the middle part of the display area of LCD screen are down.
Optionally, in some embodiments, the fingerprint recognition device further comprises: and the optical filter is used for filtering optical signals which are not used for fingerprint detection. For example, the visible light transmitted to the filter can be filtered, so that the recognition quality of the
In the embodiment of the present application, the optical filter may be specifically configured to filter out visible wavelengths, for example, visible light used for image display. The optical filter may in particular comprise one or more optical filters, which may be configured, for example, as a band-pass filter, to filter out light emitted by the visible light source, while not filtering out infrared light signals. The one or more optical filters may be implemented, for example, as an optical filter coating formed on one or more continuous interfaces, or may be implemented as one or more discrete interfaces.
It should be understood that the filter may be fabricated on the surface of any optical component or along the optical path to the
Optionally, in some embodiments of the present application, as shown in fig. 8, the backlight module 4 further includes a brightness enhancement film 42 and a diffusion film 43. The diffusion film 43 is used to improve the brightness of the front surface of the
Optionally, in some embodiments of the present application, the brightness enhancement film 42 may be placed between the diffuser film 43 and the
Optionally, in some embodiments of the present application, the brightness enhancement film 42 may be implemented by a prismatic film.
The prism film can condense light emitted from the diffusion film 43 uniformly diverging to various angles onto an axial angle, that is, a front view angle, by improving the angular distribution of a visible light signal for displaying an image, that is, to improve axial luminance without increasing the total flux of emitted light.
In other words, the prism film can select the incident light to allow the light in the angle of the convergent light to pass through, and the light out of the condition is reflected back to the diffusion film 43, diffused again in the diffusion film 43 and returned to the prism film until the emergent condition is met.
Alternatively, in some embodiments of the present application, the brightness enhancement film 42 can be implemented with a reflective polarizer.
The reflective polarizer, which is different from a prism, can be circularly brightened according to the selection of the polarization direction of the visible light signal, can accurately reflect 100% of polarized light parallel to the optical axis direction of the reflective polarizer, and can normally penetrate the reflective polarizer by polarized light in the other orthogonal direction.
It should be understood that the structure of the backlight module 4 shown in fig. 8 is merely an example, and the embodiment of the present application is not limited thereto. For example, in other alternative embodiments, the backlight module 4 may not include the steel plate 46, or may further include a compound film disposed above the brightness enhancement film for receiving the enhanced light signal from the brightness enhancement film and using the received light signal for further enhancement to indicate the brightness of the display panel.
Optionally, in some embodiments of the present application, the infrared
For example, the infrared
Optionally, in some embodiments of the present application, the optical glue may be any one of an optical liquid glue or an optical solid glue.
Optionally, in some embodiments of the present application, the optical refractive index of the optical adhesive and the optical refractive index of the LCD
Optionally, in some embodiments of the present application, the infrared
Optionally, in some embodiments of the present application, the infrared
In other alternative embodiments, the infrared
Optionally, in some embodiments of the present application, when the infrared
For example, as shown in fig. 11, the fingerprint identification device may include two
For another example, as shown in fig. 12, the fingerprint recognition device may include four
For another example, as shown in fig. 13, the under-screen fingerprint identification apparatus 10 may include a belt-shaped light source, the belt-shaped light source may include a plurality of infrared
Optionally, in some embodiments of the present application, the infrared
Optionally, in some embodiments of the present application, the infrared
In the embodiment of the present application, the infrared light signal that infrared
The embodiment of the present application further provides a backlight module, as shown in fig. 14, the
the
Optionally, in some embodiments of the present application, the
Optionally, in some embodiments of the present application, the depth of the
Optionally, in some embodiments of the present application, a vertical height of a bottom surface of the
Optionally, in some embodiments of the present application, a dimension of the groove in a direction parallel to the LCD screen is set to be greater than or equal to a corresponding dimension of a field angle FOV of the fingerprint identification module on the light guide plate.
Optionally, in some embodiments of the present application, a dimension of the groove in a direction parallel to the LCD screen is set to be greater than or equal to a dimension corresponding to a position of the FOV of the fingerprint identification module on the upper edge of the groove.
Optionally, in some embodiments of the present application, the lower surface of the light guide plate is provided with light guide points, and the density of the light guide points in the groove region is different from the density of the light guide points in the peripheral region of the groove.
Optionally, in some embodiments of the present application, the density of the light guide points in the groove region is set such that the brightness of the display screen corresponding to the groove region is equivalent to the brightness of the display screen corresponding to the surrounding region, so as to make the brightness of the entire LCD screen uniform.
Optionally, in some embodiments of the present application, the groove is circular or square in shape.
Optionally, in some embodiments of the present application, the backlight module further includes a steel plate disposed below the reflective film, an opening is formed in the steel plate, and the fingerprint identification module is disposed below the opening to receive the infrared light signal returned from the human finger and passing through the opening.
Optionally, in some embodiments of the present application, the size of the opening is greater than or equal to the corresponding size of the FOV of the fingerprint identification module on the steel plate, so that the infrared light signal returning from the human finger within the FOV of the fingerprint identification module can be received by the fingerprint identification module.
Optionally, in some embodiments of the present application, the groove is disposed in a middle region or a middle lower region of the light guide plate, so that the fingerprint detection region of the fingerprint identification module is located in a middle position or a middle lower position of the display region of the LCD screen.
Optionally, in some embodiments of the present application, the backlight module further includes a diffusion film and a brightness enhancement film disposed above the light guide plate, wherein a light signal emitted from a light source for displaying an image of the LCD screen passes through the light guide plate and then is transmitted to the diffusion film, the light signal diffused by the diffusion film is transmitted to the brightness enhancement film, and the brightness enhancement film is configured to enhance the received light signal and transmit the enhanced light signal to a display unit of the LCD screen for displaying the image.
Optionally, in some embodiments of the present application, the transmittance of the infrared light signal on the reflective film is greater than the transmittance of the light signal on the reflective film for image display of the LCD panel.
Optionally, in some embodiments of the present application, a reflectivity of the infrared light signal on the reflective film is less than a reflectivity of a light signal on the reflective film for image display of an LCD panel.
It should be understood that the
The embodiment of the present application further provides an electronic device, as shown in fig. 15, the electronic device 70 may include a fingerprint identification device 71, a backlight module 72 and a liquid crystal panel 73, where the fingerprint identification device 71 is disposed below the backlight module 72, and the backlight module is configured to provide a light source for the liquid crystal panel 73.
Optionally, in some embodiments of the present application, the fingerprint identification device 71 may be the fingerprint identification device in fig. 8, and for specific implementation, reference is made to the related description of the foregoing embodiments, and for brevity, details are not repeated here.
Optionally, in some embodiments of the present application, the backlight module 72 may be the backlight module 4 in fig. 8 or the
Optionally, the electronic device 80 may further include: an infrared light source and a liquid crystal panel. The backlight module 71 and the infrared light source are both arranged below the liquid crystal panel, and the fingerprint identification module is arranged below the backlight module 72; the fingerprint identification module is used for receiving the infrared light signal which is emitted by the infrared light source and irradiates the human finger and penetrates through the backlight module 72, and the infrared light signal is used for acquiring a fingerprint image of the human finger.
As shown in fig. 16, the display screen 80 may include a backlight module 81, where the backlight module 81 may be the backlight module 4 in fig. 8 or the
The embodiment of the present application also provides an electronic device, which includes the display screen 80 in fig. 16.
It is to be understood that the terminology used in the embodiments of the present application and the appended claims is for the purpose of describing particular embodiments only and is not intended to be limiting of the embodiments of the present application.
For example, as used in the examples of this application and the appended claims, the singular forms "a," "an," "the," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.
Those of skill in the art would appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, or combinations of computer software and electronic hardware. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the embodiments of the present application.
If implemented in the form of software functional units and sold or used as a stand-alone product, may be stored in a computer readable storage medium. Based on such understanding, the technical solutions of the embodiments of the present application may be essentially implemented or make a contribution to the prior art, or may be implemented in the form of a software product stored in a storage medium and including several instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the methods described in the embodiments of the present application. And the aforementioned storage medium includes: u disk, removable hard disk, read only memory, random access memory, magnetic or optical disk, etc. for storing program codes.
It is clear to those skilled in the art that, for convenience and brevity of description, the specific working processes of the above-described apparatuses, devices and units may refer to the corresponding processes in the foregoing method embodiments, and are not described herein again.
In the several embodiments provided in the present application, it should be understood that the disclosed electronic device, apparatus and method may be implemented in other ways.
For example, the division of a unit or a module or a component in the above-described device embodiments is only one logical function division, and there may be other divisions in actual implementation, for example, a plurality of units or modules or components may be combined or may be integrated into another system, or some units or modules or components may be omitted, or not executed.
Also for example, the units/modules/components described above as separate/display components may or may not be physically separate, may be located in one place, or may be distributed over a plurality of network elements. Some or all of the units/modules/components can be selected according to actual needs to achieve the purposes of the embodiments of the present application.
Finally, it should be noted that the above shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, devices or units, and may be in an electrical, mechanical or other form.
The above description is only a specific implementation of the embodiments of the present application, but the scope of the embodiments of the present application is not limited thereto, and any person skilled in the art can easily conceive of changes or substitutions within the technical scope of the embodiments of the present application, and all the changes or substitutions should be covered by the scope of the embodiments of the present application. Therefore, the protection scope of the embodiments of the present application shall be subject to the protection scope of the claims.
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