Fingerprint imaging component, fingerprint imaging module and electronic device

Abstract

The present application provides a fingerprint imaging component, a fingerprint imaging module, and an electronic device for reducing the process complexity of the fingerprint imaging component and improving the signal recognition accuracy of the fingerprint imaging component. The fingerprint imaging component in the present application includes: a diffraction layer, a wavelength selection layer, and a photosensitive layer arranged in sequence; the diffraction layer includes a plurality of metal ring bands arranged in an array; the metal ring band combination includes a plurality of spaced metal rings and diffraction slits with different spacings formed between the metal rings, and the ring band widths of each metal ring in the metal ring band combination are different; the wavelength selection layer is formed with a first type of through hole for passing a preset wavelength of light, the first type of through hole is located at the real focus of diffraction generated by the preset wavelength of light passing through the diffraction slit on the diffraction layer; the photosensitive layer includes a plurality of pixel circuit units arranged in an array, and the pixel circuit unit is used to perform imaging according to the received light.

Description

Technical Field

[0001] The present invention relates to the technical field of fingerprint recognition, and in particular to a fingerprint imaging component, a fingerprint imaging module and an electronic device. Background Art

[0002] Fingerprint recognition functions are becoming more and more widely used in smartphones or electronic devices. Taking mobile phones as an example, fingerprint recognition can be used to achieve functions such as unlocking, payment, and transfer.

[0003] To meet the demands of full-screen and lightweight electronic devices, fingerprint signal collection currently operates in two ways: using a microlens (microlens) or through a light collimation channel. Both methods utilize geometric optics to collect light signals, and both require coating the surface of the photosensitive device with a special thin film to select the desired spectral band.

[0004] Existing technology requires coating a special thin film on the surface of the photosensitive device to select the spectral bands that need to be transmitted. Due to the high refractive index of the oxide on the wafer surface, many thin film layers are required, making the process complex. Moreover, the angle of incidence of light affects the spectral transmission performance, affecting the accuracy of fingerprint recognition. Summary of the Invention

[0005] The present application provides a fingerprint imaging component, a fingerprint imaging module and an electronic device for reducing the process complexity of the fingerprint imaging component and improving the signal recognition accuracy of the fingerprint imaging component.

[0006] In a first aspect, the present application provides a fingerprint imaging assembly, which may include:

[0007] It includes a diffraction layer, a wavelength selection layer and a photosensitive layer arranged in sequence;

[0008] The diffraction layer comprises a plurality of metal ring bands arranged in an array; the metal ring bands comprise a plurality of spaced metal rings and diffraction slits with different spacings between the metal rings; the width of each metal ring in the metal ring bands is different, and light of different wavelengths forms multiple light convergence points after passing through the diffraction layer;

[0009] The wavelength selection layer is formed with a first type of through hole for passing light of a preset wavelength, the first type of through hole being located at a real focus of diffraction generated by light of the preset wavelength passing through the diffraction slit on the diffraction layer, thereby allowing light of the preset wavelength to pass through the first type of through hole and blocking light of non-preset wavelengths passing through the diffraction layer;

[0010] The photosensitive layer includes a plurality of pixel circuit units arranged in an array, and the pixel circuit units are used to perform imaging according to the light received from the wavelength selection layer.

[0011] Optionally, as a possible implementation manner, the total number of the metal rings included in the metal ring belt combination and the diffraction slits formed between the metal rings is not less than 7.

[0012] Optionally, as a possible implementation manner, the diameter of the outermost metal ring in the metal ring belt combination is not greater than 50 microns and the thickness of the metal ring is not greater than 1.2 microns.

[0013] Optionally, as a possible implementation, the fingerprint imaging component in the present application may further include: a filter layer arranged between the wavelength selection layer and the diffraction layer to filter the light signal generated by high-order diffraction; a second type of through hole for passing light of a preset wavelength is formed on the filter layer, and the diameter of the second type of through hole is larger than that of the first type of through hole.

[0014] Optionally, as a possible implementation, the ring distribution of the metal ring combination is as follows: the even-numbered rings are diffraction slits formed around the starting metal ring or formed by the gaps between adjacent metal rings, and the odd-numbered rings are metal rings.

[0015] Optionally, as a possible implementation manner, the ring bands in the metal ring band combination are distributed as follows: even-numbered rings are metal rings, and odd-numbered rings are diffraction slits formed by gaps between adjacent metal rings.

[0016] Optionally, as a possible implementation manner, the preset wavelength light is one or more of a red light signal, a green light signal, and a blue light signal.

[0017] Optionally, as a possible implementation manner, the wavelength selection layer is formed with a plurality of first-type through holes, wherein at least two of the first-type through holes select light of different preset wavelengths to pass therethrough.

[0018] A second aspect of the present application provides an electronic device having a fingerprint recognition area, the electronic device comprising: a fingerprint imaging component as in the first aspect and any possible embodiment of the first aspect, the fingerprint imaging component being arranged below the fingerprint recognition area and configured to output an electrical signal corresponding to signal light carrying a fingerprint signal reflected from a measured object in the fingerprint recognition area.

[0019] It can be seen from the above technical solutions that this application has the following advantages:

[0020] The fingerprint imaging assembly in this application is equipped with a diffraction layer comprising a plurality of metal ring bands arranged in an array. A wavelength selection layer is provided at the actual focus of light of a preset wavelength after diffraction through the diffraction slits in the diffraction layer, thereby selecting light of the preset wavelength. Compared with related technologies, this application does not require the coating of a special thin film on the surface of the photosensitive device to select the spectral band to be transmitted, reducing the process complexity of the fingerprint imaging assembly. Moreover, by acquiring light based on the diffraction of light, the influence of the incident angle of light on the spectral transmission performance is avoided, thereby improving the accuracy of the fingerprint imaging assembly's signal recognition. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a schematic diagram of an embodiment of a fingerprint imaging component in this application;

[0022] Figure 2 A top view and a side view of a metal ring belt assembly in this application;

[0023] Figure 3 1. A top view and a side view of another metal ring belt combination in the present application;

[0024] Figure 4 This is a schematic diagram of another embodiment of a fingerprint imaging component in this application. DETAILED DESCRIPTION

[0025] The present application provides a fingerprint imaging component, a fingerprint imaging module and an electronic device for reducing the process complexity of the fingerprint imaging component and improving the signal recognition accuracy of the fingerprint imaging component.

[0026] In order to enable those skilled in the art to better understand the present invention, the technical solutions in this application will be clearly and completely described below in conjunction with the drawings in this application. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0027] The terms "first," "second," "third," "fourth," and the like in the specification and claims of the present invention and in the accompanying drawings are used to distinguish similar objects and are not necessarily used to describe a particular order or precedence. It should be understood that the terms used in this manner are interchangeable where appropriate so that the embodiments described herein can be implemented in an order other than that illustrated or described herein. In addition, the terms "including" and "having," and any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such processes, methods, products, or apparatus.

[0028] For easier understanding, see Figure 1 The specific process in this application is described below. An embodiment of a fingerprint imaging component in this application may include: a diffraction layer 10, a wavelength selection layer 20 and a photosensitive layer 30 arranged in sequence.

[0029] The diffraction layer 10 comprises a plurality of metal ring bands arranged in an array; the metal ring bands comprise a plurality of spaced metal rings and diffraction slits with different spacings between the metal rings. For example, see Figure 2 or Figure 3 , Figure 2 Shown are top and side views of another possible combination of metal ring bands, where the even-numbered rings (0, 2, 4, 6, etc.) are diffraction slits and the odd-numbered rings (1, 3, 5, 7, etc.) are metal rings. Figure 3 Shown are top and side views of a possible combination of metal ring bands, where the odd-numbered rings (1, 3, 5, 7, etc.) are diffraction slits and the even-numbered rings (0, 2, 4, 6, etc.) are metal rings.

[0030] It should be noted that the width of each metal ring in the metal ring band group is different, and the intervals between the diffraction slits formed between adjacent metal rings are also different.

[0031] Preferably, the diameter of the outermost metal ring in the metal ring band combination is not greater than 50 microns and the thickness of the metal ring is not greater than 1.2 microns. In actual application, reasonable settings can be made according to actual needs and are not limited here.

[0032] Preferably, the total number of diffraction slits formed between the metal rings and the metal rings included in the metal ring belt combination is not less than 7 to achieve higher diffraction efficiency. In practical applications, reasonable settings can be made according to actual needs, for example, the number of diffraction slits is 6, which is not limited here.

[0033] The wavelength selection layer 20 in the present application is formed with a first type of through hole for passing light of a preset wavelength. The first type of through hole is located at the real focus of diffraction generated by the light of the preset wavelength passing through the diffraction slit on the diffraction layer, thereby allowing the light of the preset wavelength to pass through the first type of through hole and blocking the light of non-preset wavelength passing through the diffraction layer.

[0034] The photosensitive layer 30 in this application may include a plurality of pixel circuit units arranged in an array, and the pixel circuit units are used to perform imaging based on the light received from the wavelength selection layer. The specific circuit structure of the pixel circuit unit can be referred to in related art and will not be described here.

[0035] Optionally, the ratio of the number of metal ring band combinations to the number of the pixel circuit units is 1:1 or 4:1, or can be 2:1 or 3:1, which is not limited here.

[0036] The fingerprint imaging assembly in this application is equipped with a diffraction layer comprising a plurality of metal ring bands arranged in an array. A wavelength selection layer is provided at the actual focus of light of a preset wavelength after diffraction through the diffraction slits in the diffraction layer, thereby selecting light of the preset wavelength. Compared with related technologies, this application does not require the coating of a special thin film on the surface of the photosensitive device to select the spectral band to be transmitted, reducing the process complexity of the fingerprint imaging assembly. Moreover, by acquiring light based on the diffraction of light, the influence of the incident angle of light on the spectral transmission performance is avoided, thereby improving the accuracy of the fingerprint imaging assembly's signal recognition.

[0037] To prevent the metal ring of the diffraction layer from being oxidized, a protective layer 40 may be provided, which may cover the upper and lower surfaces of the metal ring and fill in the spaces between the metal rings.

[0038] Optionally, as a possible embodiment, a plurality of metal ring band combinations can be set on the diffraction layer of the fingerprint imaging component in the present application, and each metal ring band combination selects a different wavelength of light to pass through. Exemplarily, one or more metal ring band combinations can be set on the diffraction layer to select one or more of red light, green light, and blue light to pass through. In practical applications, the required light to be selected to pass through can be set according to actual needs, and is not limited here. Correspondingly, the wavelength selection layer is formed with a plurality of first-class through holes, wherein at least two first-class through holes select different wavelengths of preset wavelength light to pass through. For example, two different first-class through holes are set to pass red light and blue light respectively.

[0039] The applicant has noticed that light will have high-order diffraction (diffraction of the second order or above) in the diffraction layer, and the high-order diffraction will interfere with the collection of light of the first-order diffraction. In order to further improve the accuracy of signal recognition, the fingerprint imaging component in this application may also include a filter layer 50 disposed between the wavelength selection layer and the diffraction layer to filter the light generated by the high-order diffraction. Optionally, as a possible embodiment, please refer to Figure 4 The filter layer 50 is formed with a second type of through-holes for transmitting light of a predetermined wavelength. To avoid interfering with the first-order diffracted light, the diameter of the second type of through-holes is larger than that of the first type of through-holes. It will be appreciated that the specific position of the filter layer can be adjusted according to actual needs to avoid interfering with the collection of the first-order diffracted light.

[0040] Based on the fingerprint imaging component provided in the above embodiment, the present application further provides a fingerprint imaging module, which may include:

[0041] A substrate having a first side and a second side opposite to the first side; the first side of the substrate is used for placing a fingerprint;

[0042] a light-emitting layer disposed on the second side of the substrate, configured to emit a first light beam penetrating the substrate; the first light beam is reflected by a fingerprint to form a second light beam penetrating the substrate;

[0043] Like the fingerprint imaging component in any of the above embodiments, the fingerprint imaging component is arranged on the second side of the substrate, and is used to converge and select the second light and obtain the user's fingerprint image based on the converged and selected second light.

[0044] The present application also provides an electronic device having the fingerprint imaging module of the present application.

[0045] As described above, the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A fingerprint imaging component, characterized in that: It includes a diffraction layer, a wavelength selection layer and a photosensitive layer arranged in sequence; The diffraction layer comprises a plurality of metal ring bands arranged in an array; wherein the metal ring bands comprise a plurality of spaced metal rings and diffraction slits with different spacings between the metal rings; the width of each metal ring in the metal ring bands is different, and light of different wavelengths forms multiple light convergence points after passing through the diffraction layer; The wavelength selection layer is formed with a first type of through hole for passing light of a preset wavelength, the first type of through hole being located at a real focus of diffraction generated by light of the preset wavelength passing through the diffraction slit on the diffraction layer, thereby allowing light of the preset wavelength to pass through the first type of through hole and blocking light of non-preset wavelengths passing through the diffraction layer; The photosensitive layer includes a plurality of pixel circuit units arranged in an array, and the pixel circuit units are used to perform imaging according to the light received from the wavelength selection layer.

2. The fingerprint imaging assembly according to claim 1, characterized in that: The total number of the metal rings contained in the metal ring belt combination and the diffraction slits formed between the metal rings is no less than 7.

3. The fingerprint imaging assembly according to claim 1, characterized in that: The diameter of the outermost metal ring in the metal ring belt combination is no more than 50 microns and the thickness of the metal ring is no more than 1.2 microns.

4. The fingerprint imaging assembly according to claim 1, characterized in that: It also includes a filter layer arranged between the wavelength selection layer and the diffraction layer to filter the optical signal generated by high-order diffraction; a second type of through hole is formed on the filter layer for passing light of a preset wavelength, and the diameter of the second type of through hole is larger than that of the first type of through hole.

5. The fingerprint imaging assembly according to claim 1, characterized in that: The ring distribution of the metal ring band combination is as follows: the even-numbered rings are diffraction slits formed by the initial metal ring or the gaps between adjacent metal rings, and the odd-numbered rings are metal rings.

6. The fingerprint imaging assembly according to claim 1, characterized in that: The ring bands in the metal ring band combination are distributed in the following manner: the even-numbered rings are metal rings, and the odd-numbered rings are diffraction slits formed by the gaps between adjacent metal rings.

7. The fingerprint imaging assembly according to claim 1, characterized in that: The preset wavelength light is one or more of a red light signal, a green light signal, and a blue light signal.

8. The fingerprint imaging assembly according to claim 1, characterized in that: The wavelength selection layer is formed with a plurality of first-type through holes, wherein at least two of the first-type through holes select light of different preset wavelengths to pass therethrough.

9. A fingerprint imaging module, characterized in that: The fingerprint imaging module includes: A substrate having a first side and a second side opposite to the first side; the first side of the substrate is used for placing a fingerprint; a light-emitting layer disposed on the second side of the substrate, configured to emit a first light beam penetrating the substrate; the first light beam is reflected by a fingerprint to form a second light beam penetrating the substrate; The fingerprint imaging assembly according to any one of claims 1 to 8 is arranged on the second side of the substrate, and is used to converge and select the second light and obtain a fingerprint image of the user based on the converged and selected second light.

10. An electronic device, characterized in that: The electronic device includes the fingerprint imaging module according to claim 9.

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