CN210402402U - Fingerprint identification device and electronic equipment - Google Patents

Abstract

The embodiment of the application provides a fingerprint identification device, and the fingerprint identification device has smaller thickness and better imaging effect. The fingerprint identification device includes: the light path guiding structure is arranged between the display screen and the optical fingerprint sensor and used for guiding light signals which are obliquely incident to the finger above the display screen at a preset angle and are reflected by the finger to the optical fingerprint sensor; the optical fingerprint sensor is arranged below the light path guide structure and used for detecting the received optical signal.

Description

Fingerprint identification device and electronic equipment

The application is a divisional application of the utility model with application date of 2019, 1 month and 22 days, application number of 201920111877.6 and name of fingerprint identification device and electronic equipment.

Technical Field

The application relates to the technical field of biological identification, in particular to an optical path modulator, a fingerprint identification device and a terminal device.

Background

With the wide application of the full-screen, the mobile terminal has more and more design requirements on the identification of the fingerprint under the screen. The traditional capacitive fingerprint identification technology is limited in penetrating capacity and difficult to apply to a fingerprint identification system under a screen, and the optical fingerprint identification technology breaks through the limitation of the thickness of a display screen and glass well, so that the capacitive fingerprint identification technology has a good application prospect.

In an optical fingerprint identification device, a light path guide structure is generally adopted to guide a reflected light signal carrying fingerprint information to an optical fingerprint sensor for collection, and the validity of the identity of a user is confirmed by comparing the collected information with fingerprint information which is registered and stored in advance. In order to meet the requirement of thinning the terminal equipment, the thickness of the optical path guiding structure can be reduced to reduce the overall thickness of the optical fingerprint identification device, but the thickness may affect the imaging effect of the optical fingerprint sensor.

SUMMERY OF THE UTILITY MODEL

The embodiment of the application provides a fingerprint identification device and electronic equipment, and the fingerprint identification device and the electronic equipment have smaller thickness and better imaging effect.

In a first aspect, a fingerprint identification device is provided, which includes:

the light path guiding structure is arranged between the display screen and the optical fingerprint sensor and used for guiding light signals which are obliquely incident to the finger above the display screen at a preset angle and are reflected by the finger to the optical fingerprint sensor;

the optical fingerprint sensor is arranged below the light path guide structure and used for detecting the received optical signal.

In one possible implementation, the optical path guiding structure includes:

a microlens array comprising a plurality of microlenses, wherein each microlens is configured to converge the received optical signal;

at least one light blocking layer is sequentially arranged below the microlens array, each light blocking layer comprises a plurality of openings corresponding to the microlenses respectively, and the openings corresponding to the same microlens in the at least one light blocking layer are used for sequentially guiding the optical signals converged by the same microlens to the optical fingerprint sensor.

In a possible implementation manner, the optical fingerprint sensor includes a plurality of optical sensing units corresponding to the microlenses, wherein an opening in the at least one light blocking layer corresponding to the same microlens is used for sequentially guiding the optical signal converged by the same microlens to the optical sensing units corresponding to the same microlens.

In a possible implementation manner, the aperture of the opening corresponding to the same microlens in the at least one light blocking layer decreases from top to bottom in sequence.

In one possible implementation, the distances between two adjacent light-blocking layers are equal.

In one possible implementation manner, the lateral spacing between the openings corresponding to the same microlens in two adjacent light blocking layers is equal.

In a possible implementation manner, the optical path guiding structure further includes a light-transmitting medium, and the microlens medium is used for filling between the at least one light-blocking layer to connect the at least one light-blocking layer.

In one possible implementation, the microlens array is disposed on an upper surface of the light-transmissive medium.

In one possible implementation, the light-transmissive medium is disposed on an upper surface of the optical fingerprint sensor.

In one possible implementation, the lenses in the microlens array are spherical microlenses or aspherical microlenses.

In one possible implementation, the optical path guiding structure includes: a light pipe array comprising a plurality of light pipes that are tilted, wherein each light pipe is configured to guide the received light signal to the optical fingerprint sensor.

In one possible implementation, the optical fingerprint sensor includes a plurality of optical sensing units corresponding to the plurality of light pipes, where each light pipe is configured to guide the received optical signal to its corresponding optical sensing unit.

In a possible implementation manner, the light guide is an optical fiber, or a through hole penetrating through the upper surface and the lower surface of the optical path guiding structure.

In one possible implementation, the preset angle is 5 ° to 35 °, for example 15 °.

In a second aspect, an electronic device for fingerprint identification is provided, which includes a display screen and the fingerprint identification apparatus in the first aspect or any possible implementation manner of the first aspect.

In one possible implementation manner, the display screen is an Organic Light Emitting Diode (OLED) display screen or a Liquid Crystal Display (LCD) display screen.

Based on above-mentioned technical scheme, the light path guide structure among the fingerprint identification device can be with the light of predetermineeing angle oblique incidence and warp finger reflection, guide to optical fingerprint sensor. Because the light path guiding structure adopts the inclined light path, and the reflection intensity of the light rays which are obliquely incident is higher than that of the light rays which are vertically incident, the imaging contrast of the optical fingerprint sensor is improved, and the thickness of the fingerprint identification device is greatly reduced.

Drawings

Fig. 1 is a schematic structural diagram of an electronic device to which the present application is applicable.

Fig. 2 is a schematic block diagram of a fingerprint identification device according to an embodiment of the present application.

Fig. 3 is a schematic structural diagram of a fingerprint identification device according to an embodiment of the present application.

Fig. 4 is a schematic diagram of an optical path guiding structure according to an embodiment of the present application.

Fig. 5 is a schematic structural diagram of a fingerprint identification device according to an embodiment of the present application.

Detailed Description

The technical solutions in the embodiments of the present application will be described below with reference to the accompanying drawings.

It should be understood that the embodiments of the present application can be applied to optical fingerprint systems, including but not limited to optical fingerprint identification systems and medical diagnostic products based on optical fingerprint imaging, and the embodiments of the present application are only described by way of example, but should not be construed as limiting the embodiments of the present application, and the embodiments of the present application are also applicable to other systems using optical imaging technology, etc.

As a common application scenario, the optical fingerprint system provided by the embodiment of the application can be applied to smart phones, tablet computers and other mobile terminals or other terminal devices with display screens; more specifically, in the terminal device described above, the fingerprint recognition device may be embodied as an optical fingerprint device, which may be disposed in a partial area or an entire area below the display screen, thereby forming an Under-display or Under-screen optical fingerprint system. Alternatively, the fingerprint identification device may be partially or completely integrated into the display screen of the terminal device, so as to form an In-display or In-screen optical fingerprint system.

As shown in fig. 1, which is a schematic structural diagram of a terminal device to which the embodiment of the present application is applicable, the terminal device 10 includes a display screen 120 and an optical fingerprint device 130, where the optical fingerprint device 130 is disposed in a local area below the display screen 120. The optical fingerprint device 130 comprises an optical fingerprint sensor comprising a sensing array 133 having a plurality of optical sensing elements 131. The area where the sensing array is located or the sensing area thereof is the fingerprint detection area 103 of the optical fingerprint device 130. As shown in fig. 1, the fingerprint detection area 103 is located in a display area of the display screen 120. In an alternative embodiment, the optical fingerprint device 130 may be disposed at other positions, such as the side of the display screen 120 or the edge opaque area of the terminal device 10, and the optical signal of at least a part of the display area of the display screen 120 is guided to the optical fingerprint device 130 through the optical path design, so that the fingerprint detection area 103 is actually located in the display area of the display screen 120. In an alternative embodiment, the optical fingerprint device 130 may be disposed at other positions, such as the side of the display screen 120 or the edge opaque area of the terminal device 10, and the optical signal of at least a part of the display area of the display screen 120 is guided to the optical fingerprint device 130 through the optical path design, so that the fingerprint detection area 103 is actually located in the 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 130, for example, by the design of optical path 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 130 may be larger than the area of the sensing array of the optical fingerprint device 130. In other alternative implementations, the fingerprint sensing area 103 of the optical fingerprint device 130 may be designed to substantially coincide with the area of the sensing array of the optical fingerprint device 130 if optical path guidance is performed, for example, by light collimation.

It should be understood that the area of the fingerprint collection area 103 may be different from the area of the sensing array of the optical fingerprint identification device 130, for example, by the design of optical path such as lens imaging, reflective folded optical path design or other optical path design such as light convergence or reflection, the area of the fingerprint collection area 103 of the optical fingerprint identification device 130 may be larger than the area of the sensing array of the optical fingerprint identification device 130. In other alternative implementations, the fingerprint capture area 103 of the optical fingerprint recognition device 130 may be designed to correspond to the area of the sensing array of the optical fingerprint recognition device 130 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 terminal 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 basically extended to the front surface of the whole terminal device 10.

As an alternative implementation, as shown in FIG. 1, the optical fingerprint device 130 includes a light detection portion 134 and an optical assembly 132. The light detecting portion 134 includes the sensing array and the reading circuit and other auxiliary circuits electrically connected to the sensing array, which can be fabricated on a chip (Die) by 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. The optical assembly 132 may be disposed above the sensing array of the light detecting portion 134, and may specifically include a Filter layer (Filter) for filtering out ambient light penetrating through the finger, a light guiding layer or a light path guiding structure for guiding reflected light reflected from the surface of the finger to the sensing array for optical detection, and other optical elements.

In particular implementations, the optical assembly 132 may be packaged with the same optical fingerprint component as the light detection portion 134. For example, the optical component 132 may be packaged in the same optical fingerprint chip as the optical detection portion 134, or the optical component 132 may be disposed outside the chip where the optical detection portion 134 is located, for example, the optical component 132 is attached to the chip, or some components of the optical component 132 are integrated into the chip.

For example, the light guide layer may specifically be a Collimator (collimater) layer manufactured on a semiconductor silicon wafer, and the collimater unit may specifically be a small hole, and in reflected light reflected from a finger, light perpendicularly incident to the collimater unit may pass through and be received by an optical sensing unit below the collimater unit, and light with an excessively large incident angle is attenuated by multiple reflections inside the collimater unit, so that each optical sensing unit can basically only receive reflected light reflected from a fingerprint pattern directly above the optical sensing unit, and the sensing array can detect a fingerprint image of the finger.

In another embodiment, the light guiding layer or the light path guiding structure may also be an optical Lens (Lens) layer, which has one or more Lens units, such as a Lens group composed of one or more aspheric lenses, and is used to focus the reflected light reflected from the finger to the sensing array of the light detecting portion 134 therebelow, so that the sensing array can perform imaging based on the reflected light, thereby obtaining the fingerprint image of the finger. Optionally, the optical lens layer may further form a pinhole in the optical path of the lens unit, and the pinhole may cooperate with the optical lens layer to enlarge the field of view of the optical fingerprint device, so as to improve the fingerprint imaging effect of the optical fingerprint device 130.

In other embodiments, the light guide layer or the light path guiding structure may also specifically adopt a Micro-Lens (Micro-Lens) layer, the Micro-Lens layer has a Micro-Lens array formed by a plurality of Micro-lenses, which may be formed above the sensing array of the light detecting portion 134 through a semiconductor growth process or other processes, and each Micro-Lens may respectively correspond to one of the sensing units of the sensing array. And other optical film layers, such as a dielectric layer or a passivation layer, can be formed between the microlens layer and the sensing unit. More specifically, a light blocking layer (or referred to as a light blocking layer) having micro holes may be further included between the microlens layer and the sensing unit, wherein the micro holes are formed between the corresponding microlenses and the sensing unit, and the light blocking layer may block optical interference between adjacent microlenses and the sensing unit, and enable light corresponding to the sensing unit to be converged into the micro holes through the microlenses and transmitted to the sensing unit through the micro holes for optical fingerprint imaging.

It should be understood that several implementations of the light guiding layer or the light path guiding structure described above may be used alone or in combination. For example, a microlens layer may be further disposed above or below the collimator layer or the optical lens layer. Of course, when the collimator layer or the optical lens layer is used in combination with the microlens layer, the specific lamination structure or optical path thereof may need to be adjusted according to actual needs.

As an alternative embodiment, the display screen 120 may adopt a display screen having a self-Light Emitting display unit, such as an Organic Light-Emitting Diode (OLED) display screen or a Micro-LED (Micro-LED) display screen. Taking an OLED display screen as an example, the optical fingerprint device 130 may use the display unit (i.e., OLED light source) of the OLED display screen 120 located in the fingerprint detection area 103 as an excitation light source for optical fingerprint detection. When the finger 140 is pressed against the fingerprint detection area 103, the display 120 emits a beam of light 111 toward the target finger 140 above the fingerprint detection area 103, and the light 111 is reflected on the surface of the finger 140 to form reflected light or scattered light by the inside of the finger 140 to form scattered light. Because the ridges (ridges) and valleys (valley) of the fingerprint have different light reflection capacities, the reflected light 151 from the ridges and the valleys 152 have different light intensities, and after passing through the optical assembly 132, the reflected light is received by the sensing array 134 in the optical fingerprint device 130 and converted into corresponding electrical signals, i.e., fingerprint detection signals; based on the fingerprint detection signal, fingerprint image data can be obtained, and fingerprint matching verification can be further performed, so that an optical fingerprint identification function is realized in the terminal device 10.

In other embodiments, the optical fingerprint device 130 may also use an internal light source or an external light source to provide an optical signal for fingerprint detection. In this case, the optical fingerprint device 130 may be adapted for use with a non-self-emissive display such as a liquid crystal display or other passively emissive display. Taking an application to a liquid crystal display having a backlight module and a liquid crystal panel as an example, to support the underscreen fingerprint detection of the liquid crystal display, the optical fingerprint system of the terminal 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 or in an edge area below a protective cover of the terminal device 10, and the optical fingerprint device 130 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 130; alternatively, the optical fingerprint device 130 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 130. When the optical fingerprint device 130 is used to provide an optical signal for fingerprint detection by using an internal light source or an external light source, the detection principle is consistent with the above description.

It should be understood that in a specific implementation, the terminal device 10 further includes a transparent protective cover plate, which may be a glass cover plate or a sapphire cover plate, positioned above the display screen 120 and covering the front surface of the terminal device 10. Therefore, in the embodiment of the present application, 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.

On the other hand, in some embodiments, the optical fingerprint device 130 may include only one optical fingerprint sensor, where the area of the fingerprint detection area 103 of the optical fingerprint device 130 is small and the location is fixed, so that the user needs to press a finger to a specific location of the fingerprint detection area 103 when performing a fingerprint input, otherwise the optical fingerprint device 130 may not acquire a fingerprint image and the user experience is poor. In other alternative embodiments, the optical fingerprint device 130 may specifically include a plurality of optical fingerprint sensors. The plurality of optical fingerprint sensors may be disposed side by side below the display screen 120 in a splicing manner, and sensing areas of the plurality of optical fingerprint sensors jointly form the fingerprint detection area 103 of the optical fingerprint device 130. That is to say, the fingerprint detection area 103 of the optical fingerprint device 130 may include a plurality of sub-areas, each sub-area corresponding to the sensing area of one of the optical fingerprint sensors, respectively, so as to extend the fingerprint collection area 103 of the optical fingerprint module 130 to the main area of the lower half of the display screen, that is, to the area that the finger presses conventionally, thereby realizing the blind-touch type fingerprint input operation. Alternatively, when the number of optical fingerprint sensors is sufficient, the fingerprint detection area 130 may also be extended to half or even the entire display area, thereby enabling half-screen or full-screen fingerprint detection.

In order to reduce the thickness of the fingerprint identification device, the thickness of the light path guiding structure may typically be reduced, for example the thickness of a collimator having an array of collimating holes, i.e. the value of the "hole depth/aperture" of the collimating holes in the collimator is reduced. However, the reduction of the "hole depth/aperture" makes the light receiving angle of the collimating hole larger, and the degree of collimation is lowered, thereby affecting the imaging effect of the optical fingerprint sensing.

Therefore, the embodiment of the application provides a fingerprint identification device, and meanwhile, the fingerprint identification device has smaller thickness and better imaging effect.

Fig. 2 shows a schematic diagram of a fingerprint recognition device according to an embodiment of the present application. As shown in fig. 2, the fingerprint recognition device 200 may be applied to an electronic device having a display screen, and the fingerprint recognition device 200 includes an optical path guiding structure (or referred to as a light path layer, an optical path modulating structure, etc.) 210 and an optical fingerprint sensor 220.

The optical path guiding structure 210 is disposed between the display screen and the optical fingerprint sensor 220, and is configured to guide an optical signal, which is obliquely incident to a finger above the display screen at a preset angle i and is reflected by the finger, to the optical fingerprint sensor 220.

An optical fingerprint sensor 220 is disposed below the optical path directing structure 210 for detecting the received optical signal.

Wherein the preset angle i is greater than 0 DEG, for example, 5 DEG-i-35 deg. After the light ray incident at the angle i is reflected by the finger, the reflection angle of the reflected light ray is equal to i. The reflected light is refracted by the lower surface of the display screen and/or the upper surface of the optical path directing structure and finally enters the optical path directing structure 210 obliquely.

Due to the inclined light path, the light path guiding structure 210 can guide the light, which is obliquely incident at the preset angle i and reflected by the finger, to the optical fingerprint sensor 220. Since the reflection intensity of the obliquely incident light is higher than that of the perpendicularly incident light, the imaging contrast of the optical fingerprint sensor 220 is improved, and the thickness of the fingerprint recognition device 200 is greatly reduced.

The embodiment of the present application provides two types of optical path guiding structures 210, which can guide oblique light. The following description is made separately.

Type 1

The optical path directing structure 210 includes a microlens array and at least one light blocking layer.

The micro lens array comprises a plurality of micro lenses, wherein each micro lens is used for converging the received optical signal.

The at least one light blocking layer is sequentially disposed under the microlens array, wherein each light blocking layer includes a plurality of openings corresponding to the plurality of microlenses, and the openings corresponding to the same microlens in the at least one light blocking layer are used for sequentially guiding the optical signal converged by the same microlens to the optical fingerprint sensor 220.

The plurality of microlens mirrors in the microlens array may be, for example, spherical microlenses or aspherical microlenses, or the plurality of microlenses includes both spherical lenses and aspherical lenses. As long as the convergence of light can be achieved. Also, the microlens may be replaced with a lens.

The optical fingerprint sensor 220 is configured to detect an incident light ray satisfying a preset angle i, and only when the incident light ray satisfying the preset angle i is incident to a finger above the display screen and reflected by the finger, the incident light ray can be guided to the optical fingerprint sensor 220 by the light path guiding structure 210, and light rays incident at other angles cannot reach the optical fingerprint sensor 220.

In the process of fingerprint identification, when a finger presses a fingerprint collection area in a display screen, the ridge of the finger is contacted with the screen, and an air gap exists between the valley of the finger and the screen, so that the intensity of light reflected by the ridge is different from that of light reflected by the valley. Wherein there is an air gap between the valleys and the screen, thereby forming a glass-air interface with greater reflection of light. Accordingly, the optical fingerprint sensor 220 receives light reflected from the valleys and images as a "bright line", and correspondingly, the optical fingerprint sensor 220 receives light reflected from the ridges and images as a "dark line".

The collimator with the collimating hole array can only receive the light vertically reflected by the finger, and in the embodiment of the present invention, the light path guiding structure 210 adopts an inclined light path, and the light incident to the finger at the predetermined angle i and reflected by the finger can reach the optical fingerprint sensor 220. Since the reflection intensity of the oblique incident light is greater than that of the perpendicular incident light, the contrast between the "bright line" and the "dark line" imaged by the optical fingerprint sensor 220 according to the collected oblique light signal is higher, and the imaging effect of the optical fingerprint sensor 220 is better.

The opening in each light blocking layer in the light path guiding structure 210 not only realizes light path guiding, but also can effectively prevent light crosstalk and block stray light, so that only light rays meeting the preset angle i can reach the optical fingerprint sensor 220 through the light path guiding structure 210.

The number of the at least one light blocking layer is not limited in the embodiments of the present application. Too many light-blocking layers increase the thickness and complexity of the light path guiding structure 210, while too few light-blocking layers may cause more interference light, which affects the imaging effect. When in actual use, a reasonable number of light blocking layers can be arranged according to requirements.

Since the light obliquely incident to the finger is still oblique after being reflected by the finger, the light path guiding structure 210 employs an oblique light path in order to guide the oblique light after being reflected, and thus, openings corresponding to the same microlens and located in different light blocking layers have a lateral distance therebetween.

That is, the openings corresponding to the same microlens in at least one light blocking layer of the light path guiding structure 210 are sequentially located on the light path of the oblique light rays converged by the microlens from top to bottom.

The lateral spacing between the openings in two adjacent light blocking layers corresponding to the same lens can be equal or unequal.

And, the distance between two adjacent light blocking layers may also be equal or unequal.

For example, when the distances between two adjacent light-blocking layers are equal, the lateral distances between the openings corresponding to the same microlens in the two adjacent light-blocking layers are also equal.

Optionally, the optical fingerprint sensor 220 includes an array of optical sensing units (or called photo-sensing pixels), a plurality of optical sensing units in the array of optical sensing units corresponding to a plurality of microlenses in the array of microlenses. The opening corresponding to the same micro lens in the at least one light blocking layer is used for sequentially guiding the optical signals converged by the same micro lens to the optical sensing units corresponding to the same micro lens.

The plurality of microlenses and the plurality of optical sensing units may be in one-to-one correspondence, or one microlens corresponds to the plurality of optical sensing units, or one optical sensing unit corresponds to the plurality of microlenses, which is not limited herein.

Optionally, the apertures of the openings corresponding to the same microlens in the at least one light blocking layer decrease from top to bottom.

Because the micro lens is used for converging the light received by the micro lens, the width of the light converged by the micro lens is gradually reduced from top to bottom. Therefore, the apertures of the openings in the different light blocking layers corresponding to the microlenses are sequentially reduced from top to bottom, so that the light reaching the optical fingerprint sensor 220 can be narrow beams, the narrow-angle receiving of the optical fingerprint sensor 220 to the light is realized, and the imaging definition of the optical fingerprint sensor 220 is further improved.

Optionally, the optical path guiding structure 210 further includes a light-transmitting medium for filling between the at least one light-blocking layer to connect the at least one light-blocking layer.

Of course, other ways of connecting and fixing the at least one light blocking layer in the light path guiding structure 210 may also be used, for example, by a bracket, and the like, which is not limited in this application.

Optionally, the microlens array is disposed on an upper surface of the light-transmissive medium.

Optionally, the optical path guiding structure 210 is disposed on an upper surface of the optical fingerprint sensor 220.

It should be understood that the optical path guiding structure 210 in the embodiment of the present application may be packaged with the optical fingerprint sensor 220, for example, the optical path guiding structure 210 may be disposed on the upper surface of the optical fingerprint sensor 220, i.e. the upper surface of the optical sensing unit array, by gluing or the like; alternatively, the optical path guiding structure 210 may be disposed above the optical fingerprint sensor 220 as a separate component from the optical fingerprint sensor 220.

The fingerprint identification device according to the embodiment of the present application will be specifically described below with reference to fig. 3 as an example. Fig. 3 shows a possible structure of the fingerprint recognition device according to the embodiment of the present application. The optical path directing structure shown in fig. 3 includes a lens array, and three light blocking Layers (LS). The micro lens array is positioned at a specific position below the display screen and is used for converging the reflected light from the finger on the display screen. The three light blocking layers are sequentially positioned below the lens array and used for guiding the light rays converged by the micro lens array to the optical fingerprint sensor. The three light-blocking layers are a light-blocking layer LS3, a light-blocking layer LS2 and a light-blocking layer LS1 from top to bottom in sequence. The three light blocking layers are filled with light transmission media.

The light-blocking layer LS3, the light-blocking layer LS2, and the light-blocking layer LS1 are perforated in an array at specified positions. The openings corresponding to the microlenses 1 are the opening 1 in the light-blocking layer LS3, the opening 2 in the light-blocking layer LS2, and the opening 3 in the light-blocking layer LS1, respectively. The distance between the microlens array and the light blocking layer LS1 is P0, and the distance between the light blocking layer LS1 and the optical sensing unit of the optical fingerprint sensor is P1. The micro lens array is arranged on the upper surface of the filling medium, and the micro lenses in the micro lens array are convex lenses with the spherical radius of R. The micro lens forms a chord length L in the upper surface of the light-transmitting medium, which is equal to the interval L between the adjacent optical sensing units of the optical fingerprint sensor. Here, it is taken as an example that each optical sensing unit corresponds to one microlens. The optical signal converged by each micro lens is sequentially guided to the corresponding optical sensing unit by the opening corresponding to the micro lens.

The working process of the optical path guiding structure will be described by taking the microlens 1 and the corresponding opening as an example. And after being reflected by the finger, the light rays incident at the preset angle i finally reach the optical fingerprint sensor through the light path guide structure. Specifically, light rays satisfying a preset angle i are incident to a finger above the display screen and are reflected by the finger, so as to obtain reflected light rays with a reflection angle equal to i, and the reflected light rays are refracted on the lower surface of the display screen and are incident to the microlens 1 at an angle θ. The micro lens 1 collects the received light, and the collected light sequentially passes through the opening 1 in the light blocking layer LS3, the opening 2 in the light blocking layer LS2 and the opening 3 in the light blocking layer LS1 and reaches the optical sensing unit corresponding to the micro lens 1 on the optical fingerprint sensor.

The aperture of the opening 1 on the light-blocking layer LS3 is D1, the aperture of the opening 2 on the light-blocking layer LS2 is D2, and the aperture of the opening 3 on the light-blocking layer LS1 is D3. Due to the fact that D1 is larger than D2 is larger than D3, light collected by the optical fingerprint sensor is narrow-angle light, and the light blocking layer LS3, the light blocking layer LS2 and the light blocking layer LS1 can block crosstalk light near the opening 1, the opening 2 and the opening 3 respectively, so that the imaging effect of the optical fingerprint sensor is improved.

The distance between the light-blocking layer LS3 and the light-blocking layer LS2 is P3, the distance between the light-blocking layer LS2 and the light-blocking layer LS1 is P2, and the distance between the light-blocking layer LS1 and the photo-sensing unit is P1. The lateral spacing between aperture 1 in light blocking layer LS3 and aperture 2 in light blocking layer LS2 is t2, and the lateral spacing between aperture 2 in light blocking layer LS2 and aperture 3 in light blocking layer LS1 is t 1. When P1 is P2 is P3, t1 is t 2.

On one hand, the light path guiding structure can guide the light signal which is incident to the finger at the preset angle i and is reflected to the optical fingerprint sensor, so that the intensity of the light signal received by the optical fingerprint sensor is increased, and the imaging effect of the optical fingerprint sensor is improved.

On the other hand, considering that the size of the optical sensing units of the optical fingerprint sensor is generally only 5um to 25um, the size of P0 is generally set to be 3 times the spacing between adjacent optical sensing units, and the spherical radius R of the microlens may be equal to the spacing between adjacent optical sensing units. Thus, the thickness of the light path guiding structure can be very thin, substantially less than 100um, and therefore, the thickness of the fingerprint identification device can be effectively reduced.

In contrast, the thickness of a collimator with an array of collimating holes is typically more than 200um, and in order to meet the imaging requirements of the collimator, the distance between the collimator and the optical fingerprint sensor is 500um, so that the thickness of the fingerprint recognition device is large.

Type 2

The light path directing structure 210 includes a light pipe array including a plurality of light pipes that are tilted, wherein each light pipe is configured to direct a received light signal to the optical fingerprint sensor 220.

As shown in fig. 4, the light path guiding structure 210 includes a plurality of light pipes, and an angle r between an axial direction of each light pipe and a normal direction perpendicular to the surface of the light path guiding structure 210 is greater than 0 °. For convenience of description, the included angle r is referred to as the tilt angle of the light pipe.

Optionally, the optical fingerprint sensor 220 includes a plurality of optical sensing units corresponding to the plurality of light pipes, wherein each light pipe is used for guiding the received light signal to its corresponding optical sensing unit.

The light incident to the finger at a predetermined angle i is reflected by the finger and enters the light path guiding structure 210, and the light path guiding structure 210 guides the light, so that the reflected light passing through each light guide of the light path guiding structure 210 is obliquely incident to the optical sensing unit of the optical fingerprint sensor at an angle r.

The light pipe cross-section of the light path guiding structure 210 may be, for example, circular, elliptical, square, or any other shape.

Alternatively, the light pipes in the light pipe array are optical fibers, or through holes penetrating the upper and lower surfaces of the optical path guiding structure 210.

The material of the non-conductive region of the optical path guiding structure 210 is opaque to the wavelength band used by the fingerprint identification device 200, and the material may be silicon, silicon carbide, silicon oxide or silicon nitride, for example.

The light path guiding structure 210 may be packaged with the optical fingerprint sensor 220, for example, the light path guiding structure 210 may be attached to the upper surface of the optical fingerprint sensor 220, or may be present as a separate component in the fingerprint recognition device 200. There may or may not be a distance between the light path directing structure 210 and the display screen.

The fingerprint identification device according to the embodiment of the present application will be specifically described below with reference to fig. 5 as an example. Fig. 5 shows a possible structure of the fingerprint recognition device according to the embodiment of the present application. The optical path directing structure shown in fig. 5 includes an array of light pipes. Wherein, the diameter of the light pipe is D, for example, can be 15 um. The optical path directing structure has a thickness T, typically less than 200 um. The distance L between two adjacent light pipes is equal to the distance L between adjacent optical sensing units of the optical fingerprint sensor, for example, L may be 15 um. Here, for example, one light guide tube corresponds to one optical sensing unit, and each light guide tube is used for guiding an oblique light signal to its corresponding optical sensing unit.

Taking the light guide tube 1 as an example, the working process of the light path guiding structure will be described. The light rays incident to the finger at a preset angle i are reflected by the finger and finally reach the optical fingerprint sensor through the light path guiding structure. Specifically, the light ray satisfying the preset angle i is incident to the finger above the display screen and is reflected by the finger, so as to obtain the reflected light ray with the reflection angle equal to i, and the reflected light ray is refracted on the lower surface of the display screen and the upper surface of the light guide pipe and finally enters the light guide pipe 1 at the angle r. The light pipe 1 guides the received light to the optical sensing unit corresponding to the light pipe 1.

It can be seen that the optical path guiding structure has a light pipe array composed of inclined light pipes, and the optical path guiding structure can be made to have a smaller thickness in the case of using light pipes of the same length. In other words, the inclined light guide can achieve a thinner thickness of the optical path guiding structure while ensuring the same aspect ratio. Moreover, by adjusting the inclination angle of the light guide pipe in the light path guide structure, the propagation path and angle of the light path can be effectively changed, so that the light path can be modulated more flexibly.

On the other hand, the light path guiding structure of the embodiment can also prevent the light signal reflected from the surface of the finger from directly and vertically entering the optical fingerprint sensor, effectively inhibits noise in the light transmission process, improves the signal-to-noise ratio of the fingerprint detection device, and therefore effectively improves the fingerprint imaging effect.

The embodiment of the application also provides electronic equipment, which comprises a display screen and the fingerprint identification device in the various embodiments of the application.

Alternatively, the display screen may be the one described above, such as an LCD display screen or an OLED display screen. When the display screen is an OLED display screen, the light-emitting layer of the display screen comprises a plurality of organic light-emitting diode light sources, wherein at least part of the organic light-emitting diode light sources are used as excitation light sources for fingerprint identification by the fingerprint identification device.

By way of example and not limitation, the electronic device may be a portable or mobile computing device such as a terminal device, a mobile phone, a tablet computer, a laptop computer, a desktop computer, a gaming device, an in-vehicle electronic device, or a wearable smart device, and other electronic devices such as an electronic database, an automobile, and an Automated Teller Machine (ATM). This wearable smart machine includes that the function is complete, the size is big, can not rely on the smart mobile phone to realize complete or partial function, for example: smart watches or smart glasses and the like, and only focus on a certain type of application function, and need to be used in cooperation with other devices such as smart phones, such as various smart bracelets for physical sign monitoring, smart jewelry and other devices.

It should be understood that the specific examples in the embodiments of the present application are for the purpose of promoting a better understanding of the embodiments of the present application, and are not intended to limit the scope of the embodiments of the present application, and that various modifications and variations can be made by those skilled in the art based on the above embodiments and fall within the scope of the present application.

The above description is only for the specific embodiments of the present application, but the scope of the present application is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present application, and shall be covered by the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims (13)

1. A fingerprint recognition device, wherein a fingerprint detection area of the fingerprint recognition device is located within a display area of a display screen, the fingerprint recognition device comprising:

the light path guiding structure is arranged between the display screen and the optical fingerprint sensor and used for guiding light signals which are obliquely incident to the finger above the fingerprint detection area at a preset angle and are reflected by the finger to the optical fingerprint sensor;

the optical fingerprint sensor is arranged below the optical path guide structure and used for detecting the received optical signals, and the optical fingerprint sensor comprises a plurality of optical sensing units.

2. The fingerprint recognition device of claim 1, wherein the optical path directing structure is packaged with the optical fingerprint sensor or is disposed above the optical fingerprint sensor as a separate component relative to the optical fingerprint sensor.

3. The fingerprint recognition device according to claim 1 or 2, wherein the optical path guiding structure comprises:

a microlens array comprising a plurality of microlenses, wherein each microlens is configured to converge the received optical signal;

and the at least one light blocking layer is sequentially arranged below the microlens array, wherein each light blocking layer comprises a plurality of openings corresponding to the microlenses respectively.

4. The fingerprint identification device according to claim 3, wherein the plurality of optical sensing units correspond to the plurality of microlenses, wherein the openings in the at least one light blocking layer corresponding to the same microlens are used for sequentially guiding the optical signals converged by the same microlens to the optical sensing units corresponding to the same microlens.

5. The fingerprint identification device of claim 4, wherein the aperture of the opening corresponding to the same microlens in the at least one light blocking layer decreases from top to bottom.

6. The fingerprint recognition device according to claim 3, wherein the distance between two adjacent light blocking layers is equal or unequal.

7. The fingerprint identification device of claim 4, wherein the lateral spacing between the openings corresponding to the same microlens in two adjacent light blocking layers is equal or unequal.

8. The fingerprint recognition device according to any one of claims 4 to 7, wherein the light path guiding structure further comprises a light-transmitting medium for filling between the at least one light-blocking layer to connect the at least one light-blocking layer.

9. The fingerprint recognition device of claim 8, wherein the microlens array is disposed on an upper surface of the optically transmissive medium.

10. The fingerprint recognition device of claim 8, wherein the optically transmissive medium is disposed on an upper surface of the optical fingerprint sensor.

11. The fingerprint recognition device according to any one of claims 4 to 7, wherein the microlenses in the microlens array are spherical microlenses or aspherical microlenses.

12. The fingerprint recognition device according to any one of claims 4 to 7, wherein the preset angle is 5 ° to 35 °.

13. An electronic device, characterized in that it comprises a display screen and a fingerprint recognition device according to any one of claims 1 to 12.

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