TWI790848B - Method and device for verifying fingerprint information - Google Patents

Abstract

A device for verifying fingerprint information is provided and includes a transparent cover plate, a display unit, a light filtering element and a sensing unit. The display unit includes display pixels, the display pixels are used to emit light signals, and the light signals are reflected on the surface of the light-transmitting cover plate to form a reflected light signal. The light filtering element is used to filter the optical signal whose direction meets the preset angle range in the reflected optical signal. The sensing unit is used to receive the optical signal screened by the light filtering element. Since the sensing unit generates fingerprint information based on the light signal whose direction is in the preset angle range filtered by the light filtering element, the accuracy of the reconstructed fingerprint information is effectively improved.

Description

A method and device for verifying fingerprint information

The invention relates to the field of electronic equipment, in particular to a method and device for verifying fingerprint information.

With the development of technology and technological progress, touch display panels have been widely used in devices that require human-computer interaction interfaces, such as operating screens of industrial computers, touch screens of tablet computers, and smart phones. Since these devices are usually accompanied by a large amount of user information during use, the protection of user information security is particularly important. Among the many information security protection methods, fingerprint recognition encryption is one of the important ones.

At present, the power-on unlocking of electronic devices generally includes two ways of sliding screen unlocking and fingerprint unlocking. Sliding screen unlocking is to compare the sliding track input by the user with the preset sliding track. If they match, the electronic device will be unlocked. Since the sliding screen unlocking method does not introduce the user's physiological feature information identification, there is a greater security. Hidden danger. Fingerprint unlocking is to compare the currently collected user fingerprint information with the pre-stored fingerprint information. If the two match, the electronic device will be unlocked. Compared with sliding screen unlocking, the security of fingerprint unlocking has been improved. Great improvement.

However, the current display panel technology, whether it is a liquid crystal display (LCD), an active matrix organic light-emitting diode (AMOLED) display, or a micro-light-emitting diode (micro-LED) display, is based on thin film The transistor (TFT) structure scans and drives a single pixel to realize the display function of the pixel array on the screen. The main structure forming the switching function of the TFT is a semiconductor field-effect transistor (FET). The main materials of the well-known semiconductor layer are amorphous silicon, polysilicon, indium gallium zinc oxide (IGZO), or organic compounds mixed with carbon nanomaterials, etc. wait. Since the photodetection diode (Photo Diode) structure can also be prepared using this type of semiconductor material, and the production equipment The equipment is also compatible with the production equipment of the TFT array, and the prepared photodiode can be directly integrated with the TFT, and the TFT can be used to scan and drive the photodiode. Therefore, in recent years, the TFT photodetection diode has begun to It is produced in the way of TFT array preparation, and is widely used in X-ray sensing flat panel devices, as described in the patents CN103829959B and CN102903721B of the People's Republic of China.

Compared with image sensing devices made of traditional crystalline materials, the optical band gap (Band gap) of the above-mentioned TFT photodetection array thin film material mainly absorbs visible light, so it is more susceptible to interference from ambient visible light to form noise. resulting in a lower signal-to-noise ratio (SNR). Restricted by this, the initial application of TFT light sensing arrays is mainly based on the application of X-ray sensing flat panel devices. The main reason is that X-rays are short-wavelength light with high collimation, and X-ray images are first incident on the sensor. The light wavelength conversion material arranged on the plate converts the X-ray image into longer-wavelength visible light and then directly transmits it to the TFT light detection array film inside the sensing plate, avoiding the noise interference caused by the visible light in the surrounding environment, as mentioned above. People's Republic of China patents CN103829959B, CN102903721B described.

If this kind of well-known TFT visible light detection array film is arranged in the display screen structure, it can be used as a realization scheme of integrating the light detection function in the display screen. However, limited by factors such as the thickness of the display screen and the aperture of the display pixel opening, the real image sensed by the light detection diode array is already an image with optical distortion such as diffraction, and because the optical signal penetrates the multi-layer structure of the display screen, And in the case of the coexistence of optical display signals and touch sensing signals, it is very difficult to extract useful optical signals from low signal-to-noise ratio scenes, and the level of technical difficulty reaches the level of single-photon imaging. The original image can only be analyzed by the algorithm based on light wave theory and reconstruction. In order to avoid this technical difficulty, it is well known that disposing the visible light sensor film in the original display screen structure will require additional optical enhancement devices, or only disposing the light sensor film in the side of the display screen, using non-vertical reflection Light rays reaching the sides are used for light image reconstruction, for example, as described in the patent CN101359369B of the People's Republic of China. However, although this type of technology can avoid the technical difficulties of low-light imaging, the additional optical device increases the thickness of the light detection display screen, and the configuration on the side of the display screen cannot satisfy the user's full-screen experience.

In short, current electronic devices still collect user fingerprint information through corresponding sensors, and users can only place their fingers on a specific position outside the screen (such as the HOME button of an Apple mobile phone). So that the user's fingerprint information can be collected by the sensor below, the operation position is fixed, and the user's sensory experience is poor.

In summary, it is particularly necessary to provide a screen unlocking solution that simultaneously authenticates the user's fingerprint information when the user slides to unlock the screen.

Based on the above and other objectives, the present invention provides a method and device for verifying fingerprint information to solve the problem of inaccurate fingerprint information reconstructed by existing sensing units.

A device for verifying fingerprint information provided by the present invention includes: a light-transmitting cover; a display unit including display pixels; the display pixels are used to send out light signals, and the light signals are reflected on the surface of the light-transmitting cover , to form a reflected light signal; a light screening element, used to filter the light signal whose direction conforms to a preset angle range in the reflected light signal; a sensing unit, used to receive the light signal filtered out by the light filtering element.

As an optional embodiment, the display unit is provided with a fingerprint identification area; the sensing unit is located below the fingerprint identification area, and is used to acquire fingerprint information on the fingerprint identification area.

As an optional embodiment, the sensing unit is further configured to receive a sliding track of the user on the fingerprint recognition area, and synchronously collect fingerprint information corresponding to the user's finger.

As an optional embodiment, the device for verifying fingerprint information further includes: a processor, configured to determine that the user's sliding track on the fingerprint identification area received by the sensing unit matches a preset sliding track , judging whether the synchronously collected fingerprint information corresponding to the user's finger matches the preset fingerprint information, and if so, unlocking the screen is completed; otherwise, the unlocking of the screen fails.

As an optional embodiment, the light screening component includes: The optical glue is used to filter the reflected light signal whose incident angle of the optical glue is greater than the first critical angle in the reflected light signal, to obtain the first reflected light signal; the first critical angle is that the reflected light signal can A critical angle at which total reflection occurs on the surface of the optical glue; the sensing unit is used to receive the first reflected light signal.

As an optional embodiment, the optical glue is bonded to the lower surface of the display unit; the refractive index of the optical glue is smaller than that of the light-transmitting cover plate.

As an optional embodiment, the light screening component further includes: an optical device, configured to filter the first reflected light signal whose incident angle on the surface of the optical device is smaller than the second critical angle among the first reflected light signals , to obtain the second reflected light signal; the second critical angle is the critical angle at which the light signal sent by the display pixel can be totally reflected on the upper surface of the transparent cover plate; the sensing unit is used to receive the second reflected light Signal.

As an optional embodiment, the light screening component includes: an optical device, configured to filter the reflected light signal whose incident angle on the surface of the optical device is smaller than the second critical angle among the reflected light signals, to obtain the second reflection Optical signal; the second critical angle is the critical angle at which the optical signal emitted by the display pixel can be totally reflected on the upper surface of the transparent cover plate; the sensing unit is used to receive the second reflected optical signal.

As an optional embodiment, the optical device is further adapted to make the second reflected light signal enter the sensing unit at an incident angle smaller than a preset angle.

As an optional embodiment, the device for verifying fingerprint information further includes: a processor, configured to perform signal superposition and reconstruction on the second reflected light signals corresponding to the light signals emitted by several groups of individual display pixels or several groups of display pixel arrays. The complete physiological feature recognition image information is output and output; each set of display pixel array includes a plurality of display pixels.

As an optional embodiment, the optical device includes a light-shielding optical device, and the light-shielding optical device includes a periodic pinhole array or an aperiodic pinhole array; or the optical device includes a phase change optical device, The phase change optical device includes a photonic crystal structure or a microlens array structure whose refractive index changes periodically, or a diffuse scattering structure whose refractive index changes aperiodically.

As an optional embodiment, the sensing unit includes a plurality of pixel detection areas, and each pixel detection area is correspondingly provided with a pixel detection structure, and each pixel detection structure includes a thin film transistor. Pixel thin film circuit and a light detection unit.

As an optional embodiment, the light detection unit includes a photosensitive diode or a photosensitive transistor.

As an optional embodiment, the sensing unit includes a photodetection film, and the photodetection film includes an array formed by a photosensitive transistor; the photosensitive transistor includes: a source; a drain, and the A photosensitive leakage current channel is formed between the lateral sides of the source electrodes; a light absorbing semiconductor layer is arranged in the photosensitive leakage current channel.

As an optional embodiment, the device for verifying fingerprint information further includes: a touch screen, arranged between the transparent cover and the display unit, for detecting the touch signal of the user's finger; processing The device is used to send a display driving signal to the display unit after receiving the touch signal of the user's finger; the display pixel is used to receive the display driving signal and send out a light signal.

Different from the prior art, the device for verifying fingerprint information described in the above technical solution includes a transparent cover, a display unit, a light screening element and a sensing unit. The display unit includes display pixels, and the display pixels are used to send out light signals, and the light signals are reflected on the surface of the light-transmitting cover plate to form reflected light signals; the light screening element is used to filter the direction of the reflected light signals to meet the predetermined An optical signal in an angle range is set; the sensing unit is used for receiving the optical signal screened out by the light screening element. Since the sensing unit generates the fingerprint information based on the optical signal whose direction is in the preset angle range filtered by the light screening element, the accuracy of the reconstructed fingerprint information can be effectively improved.

1: Translucent cover/touch screen

2: Self-luminous diode display screen

21: display pixels

3: Light detection array film

31: photosensitive pixel

4: Optical glue

5: Optics

101:Gate

102: source

103: drain

104: insulation layer

105: Light-absorbing semiconductor layer

FIG. 1 is a schematic diagram of an application structure of a light detection array thin film according to an embodiment of the present invention.

FIG. 2 is a schematic diagram of display pixels of a self-luminous diode display screen according to an embodiment of the present invention.

FIG. 3 is a schematic diagram showing the change of the light path of light emission and reflection of a single display pixel according to an embodiment of the present invention.

FIG. 4 is a schematic diagram showing the change of the optical path of the luminous reflection of a single display pixel after the optical glue is installed according to an embodiment of the present invention.

FIG. 5 is a schematic diagram of light path changes of light reflection of a single display pixel after optical glue and optical devices are arranged according to an embodiment of the present invention.

FIG. 6 is a schematic diagram of an effective light-emitting area corresponding to a single display pixel according to an embodiment of the present invention.

FIG. 7 is a schematic structural diagram of a device for verifying fingerprint information according to an embodiment of the present invention.

FIG. 8 is a flowchart of a method for collecting fingerprint information according to an embodiment of the present invention.

FIG. 9 is a schematic structural diagram of a light detection unit according to an embodiment of the present invention.

FIG. 10 is a schematic structural diagram of a light detection unit according to another embodiment of the present invention.

FIG. 11 is a schematic structural diagram of a source and a drain according to another embodiment of the present invention.

FIG. 12 is a flowchart illustrating the preparation of a light detection unit according to another embodiment of the present invention.

FIG. 13 is a flowchart of a method for verifying fingerprint information according to an embodiment of the present invention.

In order to explain in detail the technical content, structural features, achieved goals and effects of the technical solution, the following will be described in detail in conjunction with specific embodiments and accompanying drawings.

As shown in FIG. 13 , it is a flowchart of a method for verifying fingerprint information according to an embodiment of the present invention. The method is applied to a device for verifying fingerprint information, and the device includes a display unit and a sensing unit. The device is an electronic device with a touch display screen, such as a smart mobile device such as a mobile phone, a tablet computer, a personal digital assistant, or an electronic device such as a personal computer or an industrial equipment computer.

The display unit is provided with a fingerprint identification area, and the sensing unit is located under the fingerprint identification area, and is used for acquiring fingerprint information on the fingerprint identification area. The display unit is a display screen that uses an active matrix thin film transistor as a scanning drive and transmits data, including an AMOLED display screen, an LCD liquid crystal display screen, a micro light emitting diode display screen, a quantum dot display screen, or an electronic ink display screen. display screen.

In this embodiment, the coverage area of the sensing unit is adapted to the size of the touch display screen, so that no matter how the user's finger slides on the display screen, the sensing unit can capture the user's fingerprint information. The sliding trajectory is the movement trajectory of the user's finger on the display unit, which can be a single-finger operation or multi-finger operation. The trajectory of the user's fingers includes but is not limited to lines, graphics, Chinese characters, etc. When the sliding track is operated by the user with multiple fingers, if the multiple fingers are in the fingerprint identification area during the sliding process, the sensing unit will collect the fingerprint information corresponding to these fingers.

In other embodiments, there may be multiple sensing units, as long as the multiple sensing units are spliced into a size suitable for the display unit and placed under the display unit. Compared with a sensing unit with a large area, a small area is easier to produce and process, which is beneficial to save production costs.

In some other embodiments, preferably, the fingerprint identification area can also be an area smaller than the size of the display screen, for example accounting for 1/2 or 1/4 of the overall size of the display screen. Preferably, the shape of the fingerprint identification area is a rectangle, The size of the rectangle is located at the center of the display unit, and the size of the sensing unit matches the size of the fingerprint recognition area. In this embodiment, when the user's finger slides on the display screen, if the finger is located outside the fingerprint recognition area, the fingerprint information will not be recognized, because the area outside the fingerprint recognition area is not provided with a sensing unit; When the user's finger slides into the fingerprint identification area, the sensing unit will capture the user's fingerprint information. Since the sensing unit only occupies part of the area of the display unit, compared with the method of full-screen coverage, the production cost can be effectively saved.

The method comprises the steps of: First enter step S1301 to receive the user's sliding track on the fingerprint identification area, and synchronously collect the fingerprint information corresponding to the user's finger.

In some embodiments, the display unit includes a touch unit; the step of "receiving the sliding track of the user's finger on the display unit" includes: the sensing unit or the touch unit receives the user's finger on the display slide track on the unit, generate slide track information, and store the slide track information. The touch control unit may be a touch screen, and the touch screen may be used to sense a user's touch operation on it, and the touch operation includes a sliding track operation. The sliding track information and the fingerprint information can both be obtained by the sensing unit, or the sliding track information can be obtained by identifying the touch unit, and the fingerprint information can be captured by the sensing unit. In short, for a terminal with a touch screen, the sliding trajectory information is captured by the sensing unit or the touch unit, which effectively improves the application range of the device.

Then enter step S1302 to determine whether the sliding track of the user on the fingerprint recognition area matches the preset sliding track, if so, enter step S1303 to determine whether the synchronously collected fingerprint information matches the preset fingerprint information, and if so, enter step S1303. S1304 Finish unlocking the screen. If the sliding track does not match the preset sliding track, or the collected fingerprint information does not match the preset fingerprint information, then go to step S1305 and fail to unlock the screen.

The preset fingerprint information is the fingerprint information entered and stored by the user in advance, and is used for comparison with the fingerprint information collected when the user performs a screen unlocking operation. The default fingerprint information can be stored in the storage unit of the device, such as the memory of the mobile phone, the hard disk of the computer, or the storage unit of the server. When it is necessary to obtain the default fingerprint information, just let the device and the server Establish a communication connection with the server, and then obtain the default fingerprint information from the server. The communication connection includes a wired communication connection or a wireless communication connection.

The comparison of fingerprint information can be realized through the fingerprint identification algorithm, which can be stored in the storage unit of the device. When the sensing unit collects the fingerprint information on the fingerprint identification area, the processor of the device calls the storage unit The fingerprint identification algorithm in the system compares the synchronously collected fingerprint information with the preset fingerprint information, and then judges whether the two match. The fingerprint recognition algorithm includes steps such as preprocessing the fingerprint image, data feature extraction, feature matching, fingerprint recognition, etc., which can be realized with a variety of algorithms. These algorithms are mature existing technologies and have been applied to various encryption The field of decryption will not be repeated here.

In this embodiment, the method further includes: when it is determined that the sliding track does not match the preset sliding track, or the collected fingerprint information does not match the preset fingerprint information, sending out prompt information. The prompt information includes one of sound prompt information, image prompt information, light prompt information, and video prompt information or more. Taking the fingerprint information mismatch as an example, "the collected fingerprint information does not match the preset fingerprint information" usually includes the following two situations: one is that the fingerprint recognition fails, that is, the fingerprint information is pre-stored in the storage unit, but the synchronous acquisition When recording the user's fingerprint information, because the user's finger end is not in sufficient contact with the screen, the collected fingerprint information is not complete, resulting in fingerprint identification failure; another situation is that the storage unit does not store any The information matches the default fingerprint information.

For the first case, when the device does not recognize the preset fingerprint information that matches the synchronously collected fingerprint information, it will send out sound prompt information or image prompt information. The voice prompt information includes voice prompt information prompting the user to input the fingerprint again (such as performing the sliding screen operation again), and the image prompt information includes a pop-up window prompting the user to input the fingerprint again (such as performing the sliding screen operation again). Information. When the number of fingerprint information input by the user is synchronously collected exceeds the preset number of times, and no preset fingerprint information matching the synchronously collected fingerprint information is identified, it is determined that the fingerprint information is not stored in the storage unit. The matching default fingerprint information is another situation mentioned above.

For the second case, that is, when there is no preset fingerprint information matching the fingerprint information stored in the storage unit, the device can also send image prompt information, such as a pop-up window prompting the user that the current fingerprint information has not been entered; Send out video prompt information, the video prompt information includes a tutorial on how to enter new fingerprint information, and the user can complete the entry of new fingerprint information according to the video prompt information. Of course, the reminder information can also be realized by means of vibration, light-sensing reminder and the like. In short, the reminder information is just to let the user know as soon as possible that "there is no fingerprint information matching the fingerprint information collected this time". As for the selection of the reminder information form, it can be adjusted according to the settings of different manufacturers.

In some embodiments, when the display unit is an LCD liquid crystal display screen or an electronic ink display screen, a backlight unit is further arranged under the sensing unit, and the sensing unit is arranged between the backlight unit and the LCD liquid crystal display screen between, or between the backlight unit and the electronic ink display screen. Since the LCD liquid crystal display screen is not a self-illuminating element, a backlight unit needs to be added under the sensing unit during installation. The backlight unit can be an LCD backlight module, or other electronic components with self-luminous function. In some other embodiments, when the display unit is an AMOLED display screen, since the OLED display screen belongs to Self-luminous components, so no backlight unit is required. Through the setting of the above two schemes, the production requirements of different manufacturers can be effectively met, and the application range of the terminal can be improved.

In some embodiments, the fingerprint identification area includes a plurality of fingerprint identification sub-areas, and a sensing unit is correspondingly arranged under each fingerprint identification sub-area. The device also includes a sensing unit control circuit, and the method further includes: receiving an activation instruction from the user for the fingerprint identification sub-area, the sensing unit control circuit turns on the sensing unit below the fingerprint identification sub-area, and receiving the user's instruction to activate the fingerprint identification sub-area. For an instruction to close the fingerprint identification sub-area, the sensing unit control circuit turns off the sensing unit below the fingerprint identification sub-area.

Taking two fingerprint identification areas as an example, the two fingerprint identification sub-areas can be evenly distributed on the screen, one above the other, or one left and one right, or they can be distributed on the screen in other arrangements. The application process of a terminal with two fingerprint identification sub-areas will be described in detail below: in the process of use, the activation signal triggered by the user is received, and the light detection devices (that is, the sensing unit) under the two fingerprint identification sub-areas are combined. Set to on. In a preferred embodiment, the range formed by the two fingerprint recognition sub-regions covers the entire display screen, which can ensure that when the light detection devices below the two fingerprint recognition sub-regions are all set to the open state, the light signals entering the display screen can be detected. The lower TFT image sensor array film (that is, the sensing unit) is absorbed to capture the user's fingerprint information.

In other embodiments, the area formed by the two fingerprint identification sub-regions may also occupy 2/3, 3/4, etc. of the entire display screen area. Of course, the user can also set the light detection device under a certain fingerprint identification sub-area to be turned on and the light detection device under another fingerprint identification sub-area to be turned off according to their own preference. When there is no need to operate the terminal, the light detection devices under the two fingerprint identification sub-regions can also be set to be off. In short, the underside of the light detection device under each fingerprint recognition sub-area is on or off, which can be set according to the user's own preference.

As shown in Figure 1, the touch display screen includes a light-transmitting cover plate, a touch screen, and a combination of self-luminous diode display pixels from top to bottom. detection unit), so as to realize the detection and identification of the user's physiological characteristics (such as fingerprint information). Taking fingerprint identification as an example, the structure shown in Figure 1 has at least the following problems when realizing fingerprint information collection: (1) After the display pixels directly below the finger irradiate the finger, light will be generated on the upper surface of the transparent cover. Penetration, Light Reflection, and Light Scattering and other different optical phenomena, whether it is the embossed or indented fingerprints, can really form bright and dark effective reflected light signals is very weak, it is even more difficult to distinguish the embossed or indented fingerprints; ( 2) Limited by the materials and related thicknesses of the light-transmitting cover, touch screen, and display screen, even if the reflected light signal is strong enough, when it passes through the light-transmitting cover, touch screen, and display, it reaches the light After detecting the array film, the light intensity has been severely weakened (usually by more than 95%). At the same time, the reflected light signal will also undergo optical distortion when passing through the TFT opening of the display screen, which affects the collection of fingerprint information; (3) Each display pixel of the light-emitting diode display screen has low luminous collimation, that is, a wide luminous angle. These large-angle luminous lights are likely to interfere with the fingerprints to be irradiated by adjacent or spaced pixel light sources, resulting in the collected fingerprint information. Inaccurate.

In order to solve the problem that the signal intensity of the reflected light entering the optical detection array film is severely reduced when the above-mentioned light detection structure detects physiological feature information, resulting in indistinct distinction of lines of captured physiological feature information and inaccurate information collection, the present invention Provided is a device for verifying fingerprint information, which can be applied to detect and identify physiological feature information, such as fingerprints and palm prints.

As shown in Figure 7, the device includes a light-transmitting cover plate, a touch screen, a self-luminous diode display screen 2, an optical glue 4, an optical device 5, and a light detection array film 3 from top to bottom; The touch screen is attached to the lower surface of the light-transmitting cover, and the optical glue 4 is attached to the lower surface of the self-luminous diode display screen 2; the refractive index of the optical glue 4 is smaller than that of the light-transmitting cover. rate, the self-luminous diode display screen includes a plurality of display pixels. For the convenience of description, all the drawings of the present invention simplify the light-transmitting cover plate and the touch screen into one, and mark it as the light-transmitting cover plate/touch screen 1. The changes that occur on the surface of the touch screen 1 are simplified to the changes that occur on the light path on the surface of the transparent cover plate.

When the photodetection array film is arranged under the display screen structure, a single display pixel or a display pixel array (which can be a row or a column of display pixels, or a plurality of display pixels arranged periodically or non-periodically) ) is used as a light source to irradiate the fingerprint above the transparent cover, and the light will be reflected. Since most of the light irradiated on the embossed pattern of the fingerprint is absorbed by the embossed skin, and the air gap between the embossed pattern and the light-transmitting cover can partially reflect the light irradiated on the embossed pattern, so the photosensitive pixels of the photodetection array film It can receive the different bright and dark features of the concave and convex lines of the fingerprint, and the light detection array film can reconstruct the convex and concave images of the fingerprint according to the bright and dark features shown by the reflected light signal.

Referring to Fig. 2, the display screen of the present invention is a self-luminous diode display screen, as the name implies, it is a display screen composed of a self-luminous diode pixel array, such as an organic light-emitting diode (OLED) display screen, a micro Light-emitting diode (micro-LED) display screen, etc. The display screen includes MxN display pixels. In order to facilitate the detailed description of the optical path change of the light signal sent by each display pixel, the present invention marks the display pixel of the Nth row and the Mth column on the display screen as Pmn, and the other display pixels The light path change can be obtained in the same way. In order to better describe the optical path changes of display pixels, the thickness of the self-luminous diode display screen involved in the present invention is less than 1/10 of the thickness of the transparent cover plate, and the refractive index of the display screen and the transparent cover plate are relatively close, so When calculating the change of the optical path, the change of the reflected light signal on the surface of the display screen can be ignored compared with that of the light-transmitting cover plate, so as to simplify the description.

Please refer to FIG. 3 , which is a schematic diagram of light path change of light reflection of a single display pixel according to an embodiment of the present invention. The upper circle in FIG. 3 represents a top view of a light beam emitted by a single display pixel Pmn with a radius smaller than R _C in the cross section. The light with a radius of R _C corresponds to an incident angle θc on the upper surface of the light-transmitting cover plate, as shown by the dotted line in FIG. 3 Location.

Since the refractive index n2 of the transparent cover is about 1.5, and the refractive index n1 of air is about 1.0, when the light source of the (m, n)th display pixel irradiates upward at a large angle, the incident angle θ on the surface of the transparent cover Light rays larger than θc (θc=sin-1(n1/n2)) will be totally reflected. Assuming that the projected length of θc corresponding to the r-axis of the circular coordinate is Rc, the light rays outside the dotted circle with the (m,n)th luminous display pixel position Pmn as the origin and Rc as the radius can pass through the light The light rays are totally reflected on the top surface of the cover plate. When the light rays with an incident angle greater than θc on the surface of the transparent cover irradiate the embossed lines of the fingerprints on the surface of the transparent cover, the original total reflection condition has been destroyed due to the refractive index of the embossed skin, resulting in The reflected signal relative to the embossed position cannot be totally reflected in the light-transmitting cover, so that part of the reflected light signal enters the light detection array film through the lower surface of the light-transmitting cover to form bright lines. On the contrary, since there is an air gap between the grooves of the fingerprint and the light-transmitting cover, the reflected light signal at the position of the grooves will maintain total reflection, and cannot reach the light detection array film to form dark stripes.

In short, compared with the light rays within the dotted circle in FIG. 3 , that is, the light rays with an incident angle greater than θc on the upper surface of the light-transmitting cover, they can be used to detect fingerprint dent areas with air gaps. Therefore one has Effective optical under-display fingerprint recognition technology needs to use Rc as the characteristic size, and use an effective light combination to irradiate or scan the finger on the transparent cover to obtain a highly sensitive reflection area for the fingerprint image. Assuming that the thickness of the touch transparent cover is h, then Rc=h‧tan-1(θc).

When the light beam emitted by the light source of the (m, n)th display pixel on the display screen is irradiated upwards at a large angle, although the incident angle θ on the upper surface of the light-transmitting cover plate is greater than the ray of θc (θc=sin-1 (n1/n2)), there will be more accurate total reflection for the fingerprint dent separated by the air gap, but the incident angle is too large when it is irradiated on the surface of the light-transmitting cover plate, the total reflection will return to the light transmission path of the light detection array film It is also getting longer and longer, which will lead to more serious attenuation of useful light and image information. When this part of the reflected light signal reaches the light detection array film, it has become noise interference with no reference value. Therefore, it is also necessary to define the light detection range of the maximum usable information when the (m, n)th display pixel is used as the light source to irradiate the fingerprint on the transparent cover.

Please refer to Fig. 4, the light screening element includes optical glue, which is used to filter the reflected light signal whose incident angle in the optical glue is greater than the first critical angle in the reflected light signal, to obtain the first reflected light signal; the sensing unit is also used for A first reflected light signal is received. The first critical angle is a critical angle at which the reflected optical signal can be totally reflected on the surface of the optical glue. In the present application, the refractive index of the optical glue is smaller than that of the transparent cover plate. The first reflected light signal obtained after filtering by optical glue screens out the light signal with too long reflection path, and the sensing unit generates fingerprint information based on the first reflected light signal, which can effectively improve the accuracy of the reconstructed fingerprint information . In addition, by adopting this scheme, by storing and utilizing effective data that can better reflect fingerprint information, some data with too long optical path are filtered out, thereby saving storage space and computing power.

Please refer to FIG. 4 and FIG. 5 , the optical glue 4 can be attached to the lower surface of the display unit (such as the self-luminous diode display screen 2 ). Since the refractive index (n3) of the optical adhesive is smaller than the refractive index (n2) of the transparent cover, the first total reflection (hereinafter referred to as "total reflection 1") occurs on the upper surface of the transparent cover and enters the optical adhesive. Among the light rays on the surface, the rays whose incident angle φ is greater than φ _c will undergo the second total reflection (hereinafter referred to as "total reflection 2") on the surface of the optical adhesive, φ _c =sin-1(n3/n2). Assuming that the projected length of φ _c corresponding to the r-axis of the circular coordinate is Rc'=h‧tan(φ _c ), on the dotted line with the (m,n)th display pixel position P _mn as the origin and 2Rc' as the radius The light outside the circle is the light ray that can be totally reflected on the surface of the optical glue. For the light rays that can be totally reflected on the surface of the optical glue, compared with the light rays within the dotted circle with 2Rc' as the radius, because the reflected light signal path is too long, there is no high-precision fingerprint. The light rays of information will therefore be filtered out by the optical glue with a refractive index n3<n2 in a way of total reflection 2.

Combining FIG. 4 and FIG. 5 , it can be known that for a single display pixel, the total reflection 1 and total reflection 2 beams in the output beams are optical signals corresponding to relatively high-precision fingerprint information. Based on this, it can be defined that when realizing the fingerprint recognition technology under the screen, after using the (m, n)th display pixel of the self-luminous diode display screen as the light source to irradiate the fingerprint, the photodetection array film can collect relative The sensitive and effective fingerprint area is the dotted line concentric ring-shaped beam area with the (m, n)th display pixel position Pmn as the origin and the radius from Rc to 2Rc' as the radius. If projected to the direction of the circular coordinate r , is the range of Rc<r<2Rc', which is the most suitable fingerprint optical information that the light detection array film can obtain from the light source emitted from a single display pixel of the light-emitting diode display screen, as shown in Figure 6 shown.

For the light rays outside the area greater than 2Rc', as mentioned above, optical glue with corresponding refractive index can be used to filter, that is, the light rays outside the area greater than 2Rc' are totally reflected on the surface of the optical glue, and will not enter the light. Detect in the thin film array, which in turn affects the collection of fingerprint information images. As for the light rays smaller than the Rc region, the present invention filters by setting optical devices above the light detection array film. In this embodiment, the optical device 4 includes a light-shielding optical device and a phase-change optical device, the light-shielding optical device includes a periodic pinhole array, or an aperiodic pinhole array, and the phase-change optical device The device includes a photonic crystal structure or a microlens array structure whose refractive index changes periodically, or a diffuse scattering structure whose refractive index changes aperiodically.

Preferably, the shape of the pinhole can be a round hole or a square hole, and the optical device can be obtained through a coded aperture (coded aperture) compression sampling method. Taking fingerprint recognition as an example, fingerprint information recognition only needs two grays, bright and dark. The application requirements of the first order, through the filtering design of the spatial frequency (in this embodiment, specifically, it is necessary to filter the light rays irradiated by the display pixels to the surface of the light-transmitting cover plate θ<θc and θ>φc), the coded aperture of the optical device Designed as a device with light guiding function, it can achieve high-resolution bright and dark light signal acquisition in the Rc<r<2Rc' area, and make the reflected light signal passing through the optical device in the vertical direction as much as possible (the incident angle is smaller than the predetermined Set the angle) into the photodetection array film. coded aperture The references for the compressed sampling method are as follows: "Coded apertures: past, present, and future application and design," by Stephen R.Gottesman (Proceeding of SPIE, Vol.6714, 2007), this article uses a simple one-dimensional model It shows that the coded aperture can be widely used in the design method of thin optical devices requiring high resolution and wide viewing angle. In short, through the coded aperture compression sampling method, the corresponding optical device can be designed according to the predetermined parameter requirements (that is, the light rays in the r<Rc area are required to be filtered after passing through the optical device), and the specific steps are as follows: The prior art will not be repeated here.

In some other embodiments, the optical device can also be designed by digital holography, and through digital holography (or called computer-generated holography), it is possible to filter out r<Rc area-wide light rays) to design corresponding optical devices, the specific steps can refer to the following literature: M.A.Seldowitz, J.P.Allebach, and D.W.Sweeney, "Synthesis of digital holograms by direct binary search," Appl.Opt.26, 2788-2798( 1987). This paper proposes that a computer can be used to design a corresponding digital holography optical device with a specific algorithm, and then realize an output image with high resolution.

In this embodiment, the device includes a light-transmitting cover plate, a touch screen, a self-luminous diode display screen, optical glue, optical devices, and a light detection array film from top to bottom; the touch screen It is attached to the lower surface of the light-transmitting cover, and the optical glue is attached to the lower surface of the self-luminous diode display screen; the refractive index of the optical glue is smaller than that of the light-transmitting cover, and the self-luminous two The polar body display screen includes a plurality of display pixels; the device also includes a processor; the method includes the following steps: First enter step S801 , when the touch screen detects the touch signal of the user's finger, the processor sends a display driving signal to the self-emitting diode display screen. Taking fingerprint information recognition as an example, when the touch screen detects that the user's finger is placed on the upper surface of the transparent cover, the touch signal is triggered.

Then go to step S802 , when the display pixel receives a display driving signal from the processor, it sends out a light signal, and the light signal is reflected on the upper surface of the light-transmitting cover to form a reflected light signal. Since the display screen and the light-transmitting cover have a certain degree of light transmittance, the light signals emitted by the display pixels will not only be reflected on the upper surface of the light-transmitting cover, but also transmitted, that is, directly pass through the upper surface of the light-transmitting cover. into the air, and only Only the light signals reflected on the upper surface of the light-transmitting cover plate will finally enter the light detection array film to form corresponding image signals. Therefore, the present invention further screens the reflected light signals.

Then enter step 803, the optical glue changes the optical path of the reflected light signal, and filters the reflected light signal whose incident angle in the optical glue is greater than the first critical angle in the reflected light signal, to obtain the first reflected light signal, and make the first reflected light signal into optics. The first critical angle is the critical angle at which the reflected optical signal can undergo total reflection on the surface of the optical glue (ie, the 'second total reflection'). In short, through the optical glue whose refractive index is smaller than that of the light-transmitting cover, the optical signal with a long light path is filtered, that is, the light rays in the r>2Rc' region.

Then enter step S804, the optical device changes the optical path of the first reflected light signal, and filters the first reflected light signal whose incident angle on the surface of the optical device is smaller than the second critical angle in the first reflected light signal, to obtain the second reflected light signal, And the second reflected light signal enters the sensing unit (that is, the light detection array film) at an incident angle smaller than the preset angle. The second critical angle is the critical angle at which the reflected light signal can be totally reflected on the surface of the transparent cover plate (that is, the 'first total reflection'). In short, it is to filter the light rays in the r<Rc region through the optical device, and make the light passing through the optical device (the radius r corresponding to the light on the coordinate axis satisfy Rc<r<2Rc') enter the photodetector as vertically as possible Measure the array film, increase the luminous flux so that the fingerprint feature information can be better captured.

Then enter step S805 and the processor generates and outputs fingerprint information according to the second reflected light signal received by the photodetection array film. That is, the light beams emitted by each display pixel are extracted to meet the requirements of the Rc<r<2Rc' area, and then the optical signals of each display pixel in this area are superimposed to reconstruct a complete physiological feature recognition Image information (such as fingerprint image information) and output.

In some embodiments, the display screen includes MxN display pixels, and the method includes: the processor sequentially drives a single display pixel or an array of display pixels on the display screen to emit light signals according to a preset timing electrical signal, so that A light spot or a combination of light spots is formed on the upper surface of the cover plate to scan the characteristic parts of the fingerprint to form a reflected light signal. For example, the first row _of display pixels on the display screen is P ₁₁ , P _{12 .} . _. P _1N , the second row is P ₂₁ , P _{22 .} Through the preset timing electrical signal, the processor can drive the display pixels on the display screen row by row and column by row, or drive the discrete display pixels with periodic changes (such as driving the first row P _11, P _13, P _15, and then driving the second row P _{21 ,} P _{23 ,} P ₂₅ , and then driving the third row P _{31 ,} P _{33 ,} P ₃₅ , and so on), of course, it is also possible to sequentially drive a plurality of display pixels arranged in non-periodical changes. In short, the sequence of driving each display pixel on the display screen to emit light can be selected according to actual needs.

In some embodiments, the photodetection array film includes PxQ pixel detection areas, each pixel detection area corresponds to a pixel detection structure, and each pixel detection structure includes more than one thin film transistor. A group is used for the pixel film circuit and a light detection unit; the light detection unit includes a photosensitive diode or a photosensitive transistor. For each light detection unit, there are several ways to realize it:

Embodiment one:

The TFT image sensing array film (that is, the light detection array film) is an array formed by photosensitive diodes, and the array formed by photosensitive diodes includes a photosensitive diode sensing area. Existing liquid crystal display (LCD) panels or organic light emitting diode (OLED) display panels all use a TFT structure to drive and scan a single pixel to realize the display function of the pixel array on the panel. The main structure forming the switching function of the TFT is a semiconductor field effect transistor (FET). The well-known semiconductor layer materials mainly include amorphous silicon, polysilicon, indium gallium zinc oxide (IGZO), or organic compounds mixed with carbon nanomaterials, etc. wait. Since the structure of the light-sensing diode can also be prepared using such semiconductor materials, and the production equipment is also compatible with the production equipment of the TFT array, in recent years, TFT light-sensing diodes (ie, photosensitive diodes) have begun to use TFT array preparation method for production. For the specific structure of the existing photodiodes, reference can be made to the description of the thin film structure of the photodetection array in US Pat. The difference between the production process of the TFT image sensing array film and the TFT structure of the display panel is that the pixel opening area of the display panel is changed to the light sensing area in the production process. Its TFT preparation method can use thin glass as the base material, and can also use high-temperature resistant plastic materials as the base material, as described in US Patent No. 6,943,070B2.

Existing TFT image sensing array films are susceptible to ambient light or the reflection and refraction of visible light emitted by display screen pixels, causing optical interference and seriously affecting the signal of the TFT image sensing array film embedded under the display panel. Noise-to-noise ratio (SNR), in order to improve the signal-to-noise ratio, as shown in Figure 9, the light detection unit of the present invention has been further improved, so that the improved TFT image sensing array film can detect and identify user body parts The reflected infrared signal. The specific structure is as follows: The photosensitive diode layer includes a p-type semiconductor layer, an i-type semiconductor layer, and an n-type semiconductor layer, and the p-type semiconductor layer, i-type semiconductor layer, and n-type semiconductor layer are stacked from top to bottom, and the i-type semiconductor layer is Microcrystalline silicon structure or amorphous germanium silicide structure. The microcrystalline silicon structure is a semiconductor layer formed by chemical vapor deposition of silane and hydrogen. The crystallinity of the microcrystalline silicon structure is greater than 40%, and its forbidden band width is less than 1.7eV. The amorphous germanium silicide structure is an amorphous semiconductor layer formed by chemical vapor deposition of silane, hydrogen and germane, and its forbidden band width is less than 1.7eV.

Bandgap refers to a bandgap width (unit is electron volts (eV)). The energy of electrons in solids cannot be continuously valued, but some discontinuous energy bands. To conduct electricity, there must be Free electrons exist, and the energy band in which free electrons exist is called the conduction band (can conduct electricity). To become free electrons, bound electrons must obtain enough energy to transition from the valence band to the conduction band. The minimum value of this energy is the forbidden band width . The bandgap width is an important characteristic parameter of semiconductors, and its size is mainly determined by the energy band structure of semiconductors, that is, it is related to the crystal structure and the bonding properties of atoms.

At room temperature (300K), the forbidden band width of germanium is about 0.66eV, and germanium is contained in silane. When germanium is added, the forbidden band width of the i-type semiconductor layer will decrease. When it is less than 1.7eV, It shows that the i-type semiconductor layer can receive optical signals in the wavelength range from visible light to infrared light (or near infrared light). By adjusting the GeH4 concentration of chemical vapor deposition, the operating wavelength range of the photosensitive diode containing amorphous or microcrystalline germanium silicide structure can be extended to the range of light wavelength from 600nm to 2000nm.

Embodiment two:

On the basis of using the first embodiment, in order to improve the quantum efficiency of photoelectric conversion, the amorphous silicon photodiode can also be formed by stacking p-type/i-type/n-type structures above double junctions. The p-type/i-type/n-type material of the first junction layer of the photodiode is still an amorphous silicon structure, and the p-type/i-type/n-type material above the second junction layer can be a microcrystalline structure, a polycrystalline structure or Doped with compound materials that can extend the photosensitive wavelength range. In short, multiple sets of p-type/i-type/n-type structures can be stacked up and down to form a photosensitive diode structure. For each p-type/i-type/n-type structure, the photosensitive diode described in Embodiment 1 is used Diode structure.

Embodiment three:

On the basis of using Embodiment 1 or Embodiment 2, for each p-type/i-type/n-type structure, the p-type semiconductor layer contained therein may be a multi-layer structure with more than two layers. For example, the p-type semiconductor layer has a three-layer structure, including a first p-type semiconductor layer (p1 layer), a second p-type semiconductor layer (p2 layer), and a third p-type semiconductor layer (p3 layer) from top to bottom. Among them, the p1 layer can adopt an amorphous structure and be heavily doped with boron (the concentration of boron is more than twice that of the standard process); The thinned p2 and p3 layers reduce the absorption of light, so that as much light as possible enters the i layer and is absorbed by the i layer, improving the photoelectric conversion rate; on the other hand, the p2 layer and p3 layer use normal boron doping It can effectively avoid the deterioration of the built-in potential due to the heavy doping of the p1 layer. When the p-type semiconductor layer includes other layers, the multi-layer structure is similar and will not be repeated here.

Likewise, the n-type semiconductor layer can also be a multi-layer structure with more than two layers. For example, the n-type semiconductor layer has a three-layer structure, including a first n-type semiconductor layer (n1 layer), a second n-type semiconductor layer (n2 layer), and a third n-type semiconductor layer (n3 layer) from top to bottom. Among them, the n3 layer can adopt an amorphous structure and be heavily doped with phosphorus (the phosphorus content is more than twice that of the standard process); n1 and n2 adopt a microcrystalline structure and are normally doped with phosphorus (according to the standard production process), relying on thickness reduction The n1 layer and n2 layer reduce the absorption of light, so that the light enters the i layer as much as possible and is absorbed by the i layer, improving the photoelectric conversion rate; on the other hand, the normal phosphorus doping of the n1 layer and n2 layer can effectively avoid The built-in potential is degraded due to heavy doping of the n3 layer. When the n-type semiconductor layer includes other layers, the multi-layer structure is similar and will not be repeated here.

Embodiment four:

The TFT image sensing array film (i.e. photodetection array film) is an array formed by photosensitive transistors, the array formed by the photosensitive transistors includes a photosensitive transistor sensing area, and the photosensitive transistor sensing area is provided with a photosensitive film Transistor. As shown in Figure 10, the photosensitive thin film transistor includes a gate 101, a source electrode 102, a drain electrode 103, an insulating layer 104, and a light-absorbing semiconductor layer 105; the photosensitive thin film transistor is an inverted coplanar structure, and the The inverted coplanar structure includes: the gate 101, the insulating layer 104, and the source 102 are vertically arranged from bottom to top, and the drain 103 and the source 102 are horizontally arranged in the same plane; Pole 101, so that between the gate 101 and the source 102, between the gate 101 and the drain 103 No contact; gap fit between the source electrode 102 and the drain electrode 103, a photosensitive leakage current channel is formed between the source electrode 102 and the drain electrode 103 laterally, and the light-absorbing semiconductor layer 105 is arranged in the photosensitive leakage current channel.

Generally, when the gate voltage is used to control the operation of the TFT in the off state, no current will flow between the source and the drain; The field effect of the structure will separate the electron-hole pairs, and then cause the TFT to generate a photosensitive leakage current. Such photosensitive leakage current characteristics allow the TFT array to be applied to photodetection or photodetection technology. Compared with the general use of TFT leakage current as a photosensitive thin film transistor device, the present invention uses an inverted coplanar field-effect transistor structure to arrange the light-absorbing semiconductor layer on the uppermost light-absorbing layer, which greatly increases the excitation of photoelectrons and improves the photoelectricity. conversion efficiency.

As shown in FIG. 12 , it is a flow chart of a method for preparing a light detection unit according to an embodiment of the present invention. The method is used to prepare the photosensitive thin film transistor (i.e., the photodetection unit) of Embodiment 6, and specifically includes the following steps: first enter step S1201, and pass through the magnetron sputtering coating on the substrate of the pixel thin film transistor to remove the gate . The base material of the pixel thin film transistor can be a hard board, or a flexible material (such as polyimide); then enter step S1202 to form an insulating film on the grid by chemical vapor deposition or magnetron sputtering. layer; then enter step S1203 to coat the n-type doped semiconductor layer of the source and the drain by chemical vapor deposition above the insulating layer, and coat the metal layer of the source and the drain by magnetron sputtering, The source and drain of the preset structure are defined by the yellow photolithography process, and the source and the drain are horizontally coplanar, and the gap is matched, so that a photosensitive leakage current channel is formed between the source and the drain laterally; and then enter the step S1204 forming a light-absorbing semiconductor layer by chemical vapor deposition in the photosensitive leakage current channel.

Embodiment five:

As far as the well-known field-effect transistor structure is concerned, the TFT used as a scan drive and data transmission switch does not need to be specially designed for the structure of collecting photocurrent between the source and the drain; however, for field-effect transistors used in photosensitive leakage current In the detection of light, if the electron-hole pairs excited by the light are separated by the field effect and driven by the electric field The moving drift (Drift) path is too long, and it is very likely that before the photoelectron fails to reach the electrode, it has recombined with the hole (Recombination), or is dangling bonded by the light-absorbing semiconductor layer itself. Defects are trapped and cannot effectively contribute to the photocurrent output for photodetection. In order to improve the influence of the photosensitive leakage current by the length of the channel between the source and the drain, so as to increase the area of the light-absorbing semiconductor without deteriorating the photoelectric conversion efficiency, the source and drain of the fourth embodiment are used in this embodiment A further improvement is made, and a new structure of source and drain is proposed.

As shown in Figure 11, the number of the source and the drain is multiple, the source and the source are connected in parallel, and the drain and the drain are connected in parallel; the gap between the source and the drain Cooperating, forming a photosensitive leakage current channel between the source and drain horizontally includes: forming a first gap between adjacent source electrodes, one drain is placed in the first gap, and a second gap is formed between adjacent drain electrodes. Two gaps, one source is placed in the second gap, the source and the drain are alternately arranged and the gaps are matched. The distance between each source and the adjacent drain is smaller than the electron drift distance, which is the distance that electrons can survive under the action of the field effect. In this way, in each detection pixel, multiple sources belonging to the same pixel are connected in parallel, and multiple drains belonging to the same pixel are also connected in parallel, which can effectively reduce the probability of recombination of photoexcited electrons and holes, The probability of success in collecting photoelectrons by the electrodes under the action of the field effect is improved, and the photosensitivity of the TFT leakage current photosensitive thin film transistor is improved to the greatest extent.

In the process of gradually preparing the photosensitive thin film transistor (ie, the photodetection unit) of the fifth embodiment, the general steps are similar to those of the photosensitive thin film transistor of the fourth embodiment. The difference is that, when preparing the source and drain, in step S1203, "define the source and drain with a preset structure through the yellow photolithography process, so that the source and drain are laterally coplanar and have a gap fit, and make the source Forming a photosensitive leakage current channel between the electrode and the drain horizontally” includes: defining a source electrode group and a drain electrode group through a yellow photolithography process, each source electrode group includes a plurality of sources, and between the source and the source Each drain electrode group includes a plurality of drain electrodes, and the drain electrodes are connected in parallel with each other; a first gap is formed between adjacent source electrodes, and a drain electrode is placed in the first gap, A second gap is formed between adjacent drains, and a source is placed in the second gap, and the source and drain are arranged in a staggered manner and the gaps are matched.

In some embodiments, the photodetection array film is used to receive a detection trigger signal, is in a photodetection state, and receives light signals reflected from detection parts (such as fingerprints, eyeballs, irises, etc.) to capture the user The detection part information; and used to receive the trigger signal of the light source, in the state of emitting light source (such as infrared light source). Preferably, the light source trigger signal and the detection trigger signal are switched alternately and conform to a preset frequency. Taking the photodetection array film as an example of an array formed by photosensitive diodes, in practical application, a bias voltage (including forward bias voltage, zero bias voltage or negative bias voltage or bias voltage) between the p-type/i-type/n-type photodiodes to realize the function of emitting infrared light from the thin film of the TFT image sensing array.

Specifically, forward bias voltage, or zero bias voltage or negative bias voltage can be alternately applied between the p-type/i-type/n-type infrared photosensitive diodes to trigger the first trigger signal or the second trigger signal. Taking the array formed by infrared photodiodes as an example with 10 columns of pixel lattices, a forward bias voltage is applied to the p-type/i-type/n-type infrared photosensitive diodes in the first cycle, so that the 10-column pixel lattices All are in the state of emitting infrared light; in the second period, zero bias or negative bias is applied to the p-type/i-type/n-type infrared photosensitive diode, so that the 10-column pixel dot matrix is in the state of infrared light detection. To capture the infrared light information reflected back by the user's eyeball, and generate the corresponding infrared image output; in the third cycle, apply forward bias voltage to the p-type/i-type/n-type infrared photosensitive diode, so that 10 columns The pixel dot matrix is in the state of emitting infrared light, alternately and repeatedly, and so on. Further, the trigger signal of the light source (ie, the first trigger signal) and the detection trigger signal (ie, the second trigger signal) are alternately switched, and the switching frequency conforms to a preset frequency. The time interval between adjacent cycles can be set according to actual needs, and the preferred time interval can be set to drive and scan each frame of the TFT array (Frame) and the infrared photosensitive diode array can receive at least one frame of complete image signals. The time, that is, the preset frequency is to switch every time the above time interval passes.

The method and device for verifying fingerprint information described in the above technical solution, the method is applied to the device for verifying fingerprint information, the device includes a display unit and a sensing unit, the display unit is provided with a fingerprint identification area, the sensing unit The measurement unit is located below the fingerprint identification area, and is used to obtain fingerprint information on the fingerprint identification area; the method includes the following steps: receiving the sliding track of the user on the fingerprint identification area, and synchronously collecting the fingerprint corresponding to the user's finger information; when it is detected that the user's sliding track on the fingerprint identification area matches the preset sliding track, it is judged whether the synchronously collected fingerprint information and the preset fingerprint information match, if so, the screen unlocking is completed, otherwise the screen unlocking fails. In this way, when the user slides to unlock the screen, the user's fingerprint information is collected and authenticated simultaneously. On the one hand, the double authentication method is used to effectively improve the security of screen unlocking. On the other hand, the user does not need to operate on specific buttons. The collection of fingerprint information can be realized, which effectively improves the user experience.

It should be noted that although the foregoing embodiments have been described herein, the scope of protection of the present invention is not limited thereby. Therefore, based on the innovative concept of the present invention, the changes and modifications made to the embodiments described herein, or the equivalent structure or equivalent process conversion made by using the description of the present invention and the contents of the accompanying drawings, directly or indirectly apply the above technical solutions In other related technical fields, all are included in the patent protection scope of the present invention.

S1301~S1305: Flow chart steps

Claims (15)

A device for verifying fingerprint information, comprising: a light-transmitting cover; a display unit including display pixels; the display pixels are used to send out light signals, and the light signals are reflected on the surface of the light-transmitting cover to form reflected light signal; a light screening element, used to filter part of the reflected light signal in the reflected light signal, and filter the light signal in the reflected light signal whose direction conforms to a preset angle range; a sensing unit, used to receive the light The optical signal screened out by the screening element. The device for verifying fingerprint information as claimed in claim 1, wherein the display unit is provided with a fingerprint identification area; the sensing unit is located below the fingerprint identification area, and is used to acquire fingerprints on the fingerprint identification area Information. The device for verifying fingerprint information according to claim 1, wherein the sensing unit is further configured to receive a sliding track of the user on the fingerprint identification area, and synchronously collect fingerprint information corresponding to the user's finger. The device for verifying fingerprint information according to claim 3, further comprising: a processor, configured to determine that the user’s sliding track on the fingerprint recognition area received by the sensing unit matches a preset sliding track , judging whether the synchronously collected fingerprint information corresponding to the user's finger matches the preset fingerprint information, and if so, unlocking the screen is completed; otherwise, the unlocking of the screen fails. The device for verifying fingerprint information as claimed in claim 1, wherein the light screening component includes: optical glue, used for reflecting light signals whose incident angle of the optical glue is larger than the first critical angle among the reflected light signals performing filtering to obtain a first reflected light signal; the first critical angle is a critical angle at which the reflected light signal can be totally reflected on the surface of the optical glue; the sensing unit is configured to receive the first reflected light signal. The device for verifying fingerprint information according to claim 5, wherein the optical glue is pasted on the lower surface of the display unit; the refractive index of the optical glue is smaller than that of the transparent cover. The device for verifying fingerprint information as claimed in claim 5, wherein the light screening component further includes: an optical device, used for the first reflected optical signal whose incident angle on the surface of the optical device is smaller than the second critical angle A reflected light signal is filtered to obtain a second reflected light signal; the second critical angle is the critical angle at which the light signal sent by the display pixel can be totally reflected on the upper surface of the transparent cover plate; the sensing unit is used to receive The second reflected light signal. The device for verifying fingerprint information as claimed in claim 1, wherein the light screening component further includes: an optical device, used for reflecting the reflected light signal whose incident angle on the surface of the optical device is smaller than the second critical angle among the reflected light signals filtering to obtain the second reflected light signal; the second critical angle is the critical angle at which the light signal emitted by the display pixel can be totally reflected on the upper surface of the light-transmitting cover plate; the sensing unit is used to receive the second reflected light signal. The device for verifying fingerprint information according to claim 7 or claim 8, wherein the optical device is further adapted to make the second reflected light signal enter the sensing unit at an incident angle smaller than a preset angle. The device for verifying fingerprint information as described in claim 7 or claim 8 further includes: a processor, configured to perform the second reflected light signal corresponding to the light signal emitted by several groups of individual display pixels or several groups of display pixel arrays The signals are superimposed to reconstruct and output complete physiological feature recognition image information; each group of display pixel arrays includes a plurality of display pixels. The device for verifying fingerprint information as claimed in claim 7 or claim 8, wherein the optical device includes a light-shielding optical device, and the light-shielding optical device includes a periodic pinhole array or an aperiodic pinhole array; or The optical device includes a phase change optical device, the phase Varying optical devices include photonic crystal structures or microlens array structures whose refractive index changes periodically, or diffuse scattering structures whose refractive index changes aperiodically. The device for verifying fingerprint information according to claim 1, wherein the sensing unit includes a plurality of pixel detection areas, each pixel detection area is correspondingly provided with a pixel detection structure, and each pixel detection structure includes A pixel thin film circuit composed of thin film transistors and a light detection unit. The device for verifying fingerprint information as claimed in claim 12, wherein the light detection unit includes a photosensitive diode or a photosensitive transistor. The device for verifying fingerprint information according to claim 1, wherein the sensing unit includes a photodetection film, and the photodetection film includes an array formed by a photosensitive transistor; the photosensitive transistor includes; a source; A photosensitive leakage current channel is formed between the drain electrode and the source electrode laterally; a light absorbing semiconductor layer is arranged in the photosensitive leakage current channel. The device for verifying fingerprint information as described in claim 1 further includes: a touch screen disposed between the transparent cover plate and the display unit for detecting the touch signal of the user's finger; processing The device is used to send a display driving signal to the display unit after receiving the touch signal of the user's finger; the display pixel is used to receive the display driving signal and send out a light signal.

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