CN107392132B - Display panel and display device - Google Patents
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- CN107392132B CN107392132B CN201710575222.XA CN201710575222A CN107392132B CN 107392132 B CN107392132 B CN 107392132B CN 201710575222 A CN201710575222 A CN 201710575222A CN 107392132 B CN107392132 B CN 107392132B
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- 230000001681 protective effect Effects 0.000 claims abstract description 52
- 239000000758 substrate Substances 0.000 claims abstract description 44
- 238000010521 absorption reaction Methods 0.000 claims abstract description 16
- 230000010287 polarization Effects 0.000 claims description 18
- 230000003287 optical effect Effects 0.000 claims description 8
- 239000000853 adhesive Substances 0.000 claims description 3
- 230000001070 adhesive effect Effects 0.000 claims description 3
- 239000007788 liquid Substances 0.000 claims description 3
- 238000010586 diagram Methods 0.000 description 8
- 238000000034 method Methods 0.000 description 8
- 238000001514 detection method Methods 0.000 description 5
- 230000000694 effects Effects 0.000 description 5
- 239000004568 cement Substances 0.000 description 4
- 230000005684 electric field Effects 0.000 description 3
- 230000004313 glare Effects 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 230000001902 propagating effect Effects 0.000 description 3
- 238000004458 analytical method Methods 0.000 description 2
- 230000000670 limiting effect Effects 0.000 description 2
- 239000010409 thin film Substances 0.000 description 2
- 230000003313 weakening effect Effects 0.000 description 2
- 229910021532 Calcite Inorganic materials 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000005530 etching Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06V—IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING
- G06V40/00—Recognition of biometric, human-related or animal-related patterns in image or video data
- G06V40/10—Human or animal bodies, e.g. vehicle occupants or pedestrians; Body parts, e.g. hands
- G06V40/12—Fingerprints or palmprints
- G06V40/13—Sensors therefor
- G06V40/1324—Sensors therefor by using geometrical optics, e.g. using prisms
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06V—IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING
- G06V40/00—Recognition of biometric, human-related or animal-related patterns in image or video data
- G06V40/10—Human or animal bodies, e.g. vehicle occupants or pedestrians; Body parts, e.g. hands
- G06V40/12—Fingerprints or palmprints
- G06V40/1347—Preprocessing; Feature extraction
- G06V40/1359—Extracting features related to ridge properties; Determining the fingerprint type, e.g. whorl or loop
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Abstract
The invention provides a display panel and a display device, the display panel includes: the array substrate, the polaroid and the protective cover plate are sequentially stacked; the fingerprint identification units are positioned on one side of the polaroid, which is far away from the protective cover plate; the Fresnel prism is positioned on one side of the array substrate, which is far away from the protective cover plate; the fingerprint identification light source is positioned on one side of the Fresnel prism, which is far away from the protective cover plate, and the fingerprint identification light source emits parallel light; the Fresnel prism is provided with a bottom surface parallel to the polaroid, and parallel light emitted by the fingerprint identification light source is incident in a way of being vertical to the light incident surface of the Fresnel prism; the incident direction of the parallel light emitted by the fingerprint identification light source and the normal of the plane where the polaroid is located form an incident surface, and the incident surface is perpendicular to or parallel to the direction of the absorption axis of the polaroid. The invention provides a display panel and a display device, which are used for improving the accuracy of fingerprint identification.
Description
Technical Field
The invention relates to the technical field of display, in particular to a display panel and a display device.
Background
Fingerprints are unique to each individual. With the development of science and technology, a variety of display devices with fingerprint identification functions appear in the market, such as mobile phones, tablet computers, intelligent wearable devices and the like. Therefore, before the user operates the display device with the fingerprint identification function, the user only needs to touch the fingerprint identification unit of the display device with a finger to carry out authority identification, and the authority identification process is simplified.
The fingerprint is composed of a series of ridges and valleys on the surface of the skin at the finger tip, and the intensity of light reflected by the ridges and valleys received by the fingerprint identification unit is different, so that the magnitude of current/voltage signals converted from the reflected light formed at the positions of the ridges and the reflected light formed at the positions of the valleys is different, and then the fingerprint identification can be performed according to the magnitude of the current/voltage signals. Generally, besides reflection, scattering and refraction occur at the ridge positions, so that the intensity of reflected light formed at the ridge positions is smaller than that of reflected light formed at the valley positions, but the intensity of reflected light formed at the ridge positions and that of reflected light formed at the valley positions are smaller, which puts higher demands on the detection capability of the fingerprint sensor and affects the accuracy of fingerprint identification.
Disclosure of Invention
The invention provides a display panel and a display device, which aim to improve the accuracy of fingerprint identification.
In a first aspect, an embodiment of the present invention provides a display panel, including:
the array substrate, the polaroid and the protective cover plate are sequentially stacked;
the fingerprint identification units are positioned on one side of the polaroid, which is far away from the protective cover plate;
the Fresnel prism is positioned on one side of the array substrate, which is far away from the protective cover plate;
the fingerprint identification light source is positioned on one side of the Fresnel prism, which is far away from the protective cover plate, and the fingerprint identification light source emits parallel light;
the Fresnel prism is provided with a bottom surface parallel to the polaroid, and parallel light emitted by the fingerprint identification light source is incident in a way of being vertical to the light incident surface of the Fresnel prism; the incident direction of the parallel light emitted by the fingerprint identification light source and the normal of the plane where the polaroid is located form an incident surface, and the incident surface is perpendicular to or parallel to the direction of the absorption axis of the polaroid.
In a second aspect, an embodiment of the present invention further provides a display device, including the display panel according to the first aspect.
The display panel provided by the invention comprises an array substrate, a polaroid, a protective cover plate, a plurality of fingerprint identification units for fingerprint identification, a fingerprint identification light source and a Fresnel prism, wherein the fingerprint identification light source can emit parallel light, and can avoid crosstalk caused by receiving reflected light rays at different touch positions by the same fingerprint identification unit, the Fresnel prism is provided with a bottom surface parallel to the polaroid, so that the display panel structure from the bottom surface of the Fresnel prism to the position between the polaroid and the protective cover plate can be regarded as a parallel flat plate, and the propagation of the light rays in the parallel flat plate conforms to the refraction law of light and is in the same plane. In the embodiment of the invention, parallel light emitted by a fingerprint identification light source is incident perpendicular to the light incident surface of a Fresnel prism, the incident direction of the parallel light emitted by the fingerprint identification light source and the normal of the plane where the polaroid is located form an incident surface, the polarization state of the parallel light emitted by the fingerprint identification light source after passing through the polaroid is changed into linear polarization, the direction of the incident surface and the direction of the absorption axis of the polaroid are perpendicular or parallel, at the moment, the polarization state of the linearly polarized light after being reflected by the protective cover plate is linear polarization, so that the linearly polarized light can reach a fingerprint identification unit through the polaroid without damage, the attenuation effect of the polaroid on fingerprint reflected light (fingerprint signals) is eliminated, and the fingerprint identification accuracy is improved.
Drawings
FIG. 1 is a schematic view of a light ray propagating in a parallel plate;
fig. 2a is a schematic cross-sectional structure diagram of a display panel according to an embodiment of the present invention;
FIG. 2b is a schematic perspective view of a portion of the display panel shown in FIG. 2 a;
FIG. 2c is a cross-sectional view of a Fresnel prism provided in accordance with an embodiment of the present invention;
fig. 3 is a schematic cross-sectional view of another display panel according to an embodiment of the invention;
fig. 4 is a schematic cross-sectional view illustrating another display panel according to an embodiment of the invention;
fig. 5a is a schematic cross-sectional view illustrating another display panel according to an embodiment of the present invention;
FIG. 5b is a diagram of the light path followed by the light shown in FIG. 5 a;
fig. 6 is a schematic cross-sectional view illustrating another display panel according to an embodiment of the present invention;
FIG. 7 is a diagram of a light path of linearly polarized light totally reflected at an interface between a protective cover plate and air;
fig. 8 is a schematic structural diagram of a display device according to an embodiment of the present invention.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. It should be further noted that, for the convenience of description, only some of the structures related to the present invention are shown in the drawings, not all of the structures.
Fig. 1 is a schematic view of light propagating in parallel plates, as shown in fig. 1, the direction of the arrow indicates the light propagating direction, a plurality of parallel plates are placed in sequence, and light incident from a first parallel plate j1 is refracted at the interface between a first parallel plate j1 and a second parallel plate j2, which can be obtained according to the light refraction law: n isj1·sin(β1)＝nj2Sin (. beta.2) in which nj1Is the refractive index of the first parallel plate j1, β 1 is the incident angle of the first parallel plate, nj2Is the refractive index of the second parallel plate, and β 2 is the incident angle of the second parallel plate; the light incident from the second parallel plate j2 is refracted at the interface between the second parallel plate j2 and the third parallel plate j3, and can be obtained according to the light refraction law: n isj2·sin(β2)＝nj3Sin (. beta.3) in which nj3Is the refractive index of the third parallel plate, beta3The incident angle of the third parallel plate can be obtained by the above analysis: n isj1·sin(β1)＝nj2·sin(β2)＝nj3·sin(β3) If a total of m parallel plates are placed in sequence, the following can be obtained by analogy according to the analysis: n isj1·sin(β1)＝nj2·sin(β2)＝nj3·sin(β3)＝...＝njmSin (. beta.m), wherein njmIs the refractive index of the mth parallel plate, and β m is the incident angle of the mth parallel plate.
The light ray incident from the first parallel plate j1 is refracted at the interface between the first parallel plate j1 and the second parallel plate j2 and then propagates linearly in the second parallel plate, the light ray propagates linearly in the m-th parallel plate after refracted at the interface between the second parallel plate j2 and the third parallel plate j3 and then propagates linearly in the third parallel plate, and so on, and the light ray in the second parallel plate j2 is the refracted light ray at the interface between the first parallel plate j1 and the second parallel plate j2 and the incident light ray at the interface between the second parallel plate j2 and the third parallel plate j3, and the light ray in the third parallel plate j3 is the refracted light ray at the interface between the second parallel plate j2 and the third parallel plate j3 and the incident light ray at the interface between the third parallel plate 3 and the fourth parallel plate j4, and so on to a plurality of parallel plates placed in sequence. It will be appreciated by those skilled in the art that incident and refracted rays are in the same plane, and that rays travel in multiple parallel plates in the same plane.
Fig. 2a is a schematic cross-sectional structure diagram of a display panel according to an embodiment of the present invention, fig. 2b is a schematic perspective structure diagram of a partial structure of the display panel in fig. 2a, fig. 2c is a cross-sectional view of a fresnel prism according to an embodiment of the present invention, and as shown in fig. 2a, fig. 2b and fig. 2c, an arrow direction indicates a light propagation direction, and the display panel includes: the array substrate 10, the polarizer 21 and the protective cover 30 are sequentially stacked. The protective cover 30 has an effect of protecting the display panel from mechanical damage, and the protective cover 30 can be in contact with fingers when the display panel is subjected to touch operation. The plurality of fingerprint identification units 40 are located on the side of the polarizer 21 away from the protective cover 30. The fresnel prism 50 is located on the side of the array substrate 10 away from the protective cover 30. The fingerprint identification light source 60 is positioned on one side of the Fresnel prism 50 far away from the protective cover 30, and the fingerprint identification light source 60 emits parallel light. The fresnel prism 50 has a bottom surface 51 parallel to the polarizer 21, the parallel light emitted by the fingerprint identification light source 60 is incident perpendicularly to the light incident surface 52 of the fresnel prism 50, the incident direction of the parallel light emitted by the fingerprint identification light source 60 and the normal of the plane of the polarizer 21 form an incident surface S0, the incident surface S0 is perpendicular or parallel to the direction of the absorption axis PP of the polarizer 21, and the direction of the incident surface S0 parallel to the direction of the absorption axis PP of the polarizer 21 is illustrated in fig. 2b without limiting the invention. Wherein, a beam of unpolarized light becomes linearly polarized light after passing through the polarizer 21, the polarization component parallel to the absorption axis PP direction of the polarizer 21 is absorbed by the polarizer, the polarization component perpendicular to the absorption axis direction of the polarizer 21 can pass through without loss, and the polarization direction of the linearly polarized light after passing through the polarizer 21 is perpendicular to the absorption axis PP direction of the polarizer 21.
The display panel provided by the embodiment of the invention comprises an array substrate, a polaroid, a protective cover plate, a plurality of fingerprint identification units for fingerprint identification, a fingerprint identification light source and a Fresnel prism, wherein the fingerprint identification light source can emit parallel light, and can avoid crosstalk caused by that reflected light rays at different touch positions are received by the same fingerprint identification unit, the Fresnel prism is provided with a bottom surface parallel to the polaroid, so that the display panel structure from the bottom surface of the Fresnel prism to the position between the polaroid and the protective cover plate can be regarded as a parallel flat plate, and the propagation of the light rays in the parallel flat plate conforms to the refraction law of light and is in the same plane. In general, a beam of linearly polarized light is reflected to be changed into a beam of elliptically polarized light, because the polarization direction of the linearly polarized light has a parallel component (parallel to the incident plane) and a vertical component (perpendicular to the incident plane) at the same time, before the linearly polarized light is incident on the reflection interface, the phase difference between the vertical component and the horizontal component is integral multiple of pi, and after the linearly polarized light is reflected by the reflection interface, the phase difference between the vertical component and the horizontal component is no longer integral multiple of pi, so that the reflected light is changed into the elliptically polarized light, and the light intensity of the elliptically polarized light is weakened after the elliptically polarized light passes through the polarizer. The incident surface is vertical or parallel to the direction of the absorption axis of the polarizer, at the moment, the polarization direction of the linearly polarized light is in the incident surface or vertical to the incident surface, namely, only one of a parallel component (parallel to the incident surface) or a vertical component (vertical to the incident surface) exists in the polarization direction of the linearly polarized light, the polarization state of the linearly polarized light after being reflected by the protective cover plate is still linear polarization, and the polarization direction is vertical to the direction of the absorption axis, so that the linearly polarized light can reach the fingerprint identification unit through the polarizer without damage, the weakening effect of the polarizer on fingerprint reflected light (fingerprint signals) is eliminated, and the accuracy of fingerprint identification is improved.
The fingerprint is composed of a series of ridges 71 and valleys 72 on the skin surface of the finger tip, and since the intensity of the light reflected by the ridges 71 and the valleys 72 received by the fingerprint recognition unit 40 is different, the magnitude of the current/voltage signal converted from the reflected light formed at the positions of the ridges 71 and the reflected light formed at the positions of the valleys 72 is different, and then the fingerprint recognition can be performed according to the magnitude of the current/voltage signal. Generally, scattering and refraction occur at the position of the ridge 71 in addition to reflection, resulting in the intensity of reflected light formed at the position of the ridge 71 being smaller than the intensity of reflected light formed at the position of the valley 72. Optionally, the protective cover 30 has a refractive index n1The refractive index of the Fresnel prism 50 is n2The incident angle of the parallel light emitted from the fingerprint identification light source 60 incident on the surface of the protective cover 30 away from the array substrate 10 is θ1The incident angle of the parallel light from the fingerprint recognition light source 60 incident on the bottom surface 51 of the Fresnel prism 50 is θ2，θ1And theta2Satisfies the following conditions:
when the parallel light emitted by the fingerprint identification light source 60 is totally reflected at the interface between the protective cover 30 and the outside air (corresponding to the position of the valley 72), the following conditions are satisfied: n is1·sinθ1≥nair·sin(90°)，Wherein n isairIs the refractive index of air, i.e. nair1, and the display panel structure from the bottom surface 51 of the fresnel prism 50 to the polarizer 21 and the protective cover 30 can be regarded as a parallel plate, n1·sinθ1＝n2·sinθ2Therefore when theta is1And theta2Satisfies the following conditions:
during the process, the parallel light emitted by the fingerprint identification light source 60 is totally reflected at the interface between the protective cover plate 30 and the outside air, and because of the total reflection, all the light energy incident to the interface between the protective cover plate 30 and the outside air is reflected to the display panel by the interface between the protective cover plate 30 and the outside air, the light intensity of the reflected light at the valley 72 position is greatly enhanced; for the position of the ridge 71, no full emission occurs, but reflection, scattering and refraction occur, the intensity of the reflected light being weak. The embodiment of the invention enhances the light intensity of reflected light at the valley position and improves the accuracy of fingerprint identification by enabling the parallel light emitted by the fingerprint identification light source to be totally reflected at the valley position of the fingerprint in the protective cover plate. In addition, the reflected light intensity at the ridge 71 position is almost unchanged, and the reflected light intensity at the valley 72 position is increased more, so that the difference between the reflected light intensity at the ridge 71 position and the reflected light intensity at the valley 72 position is increased, the contrast is improved, and the clear fingerprint detection image is more favorably formed. In order to obtain a clearer fingerprint detection image, in one embodiment, for example, the detection values of the fingerprint identification unit 40 may be divided into two levels: 0 and 1. Wherein 0 corresponds to the light intensity received by the fingerprint identification unit 40 being less than the set threshold, i.e. 0 corresponds to the position of the ridge 71; a 1 corresponds to when the intensity of light received by the fingerprint identification unit 40 is equal to or greater than the set threshold, i.e., a 1 corresponds to the position of the valley 72. Alternatively, setting 0 corresponds to when the intensity of light received by the fingerprint identification unit 40 is greater than or equal to a set threshold, i.e., 0 corresponds to the position of the valley 72; a 1 corresponds to when the intensity of light received by the fingerprint identification unit 40 is less than the set threshold, i.e. a 1 corresponds to the location of the ridge 71.
Optionally, the Fresnel prism is a triangular prismThe external shape of the triangular prism is a triangular prism, and generally, the side surface of the triangular prism is used as the light incident surface, the reflection interface/the refraction interface of the triangular prism, and the incident light is in the cross section of the triangular prism. The section of the triangular prism is an isosceles triangle, and the vertex angle of the isosceles triangle is
From fig. 2c, it can be seen that:
namely, it is
Satisfies the following conditions:
it can be seen that when the incident angle of the parallel light emitted from the fingerprint identification light source 60 to the bottom surface 51 of the Fresnel prism 50 is known as θ2Can be according to the formula
To obtain the size of the apex angle of the triangular prism with the cross section of an isosceles triangle.
Optionally, the protective cover 30 has a refractive index n1The refractive index of the Fresnel prism 50 is n2The protective cover 30 has the same refractive index as the Fresnel prism 50, i.e., n1＝n2At this time, theta1＝θ2. The protective cover 30 and the fresnel prism 50 are made of the same material so as to have the same refractive index.
Optionally, the protective cover 30 is attached to the surface of the polarizer 21 on the side away from the array substrate 10 by liquid optical adhesive 80. The liquid optical adhesive 80 has the characteristics of being colorless and transparent, having the light transmittance of more than 98 percent, good bonding strength, being capable of being cured at normal temperature or medium temperature, and having the characteristics of small curing shrinkage rate, yellowing resistance and the like.
Fig. 3 is a schematic cross-sectional view of another display panel according to an embodiment of the invention, as shown in fig. 3, the direction of the arrow indicates the propagation direction of light, and the fingerprint identification units 40 are located on a side of the array substrate 10 away from the polarizer 21. If the fingerprint recognition unit 40 is disposed in the display panel, for example, if the fingerprint recognition unit 40 is disposed in the array substrate 10 of the display panel, the compatibility between the fingerprint recognition unit 40 and the organic light emitting structure in the array substrate, and the compatibility between the data lines, the scan lines, etc. need to be considered, the design is complex, and the original display panel production equipment and process need to be changed. Therefore, the plurality of fingerprint identification units are arranged on one side of the array substrate, which is far away from the polaroid, and the detection of fingerprints can be realized on the basis of not changing the original functional design of the display panel.
Optionally, the display panel further includes a first substrate 90, the first substrate 90 is located between the array substrate 10 and the fresnel prism 50, and the plurality of fingerprint identification units 40 are integrated on a surface of the first substrate 90 on a side away from the fresnel prism 50. The first substrate 90 functions to support and protect the plurality of fingerprint recognition units 40.
Fig. 4 is a schematic cross-sectional view of another display panel according to an embodiment of the invention, as shown in fig. 4, the direction of the arrow indicates the light propagation direction, and the first substrate 90 and the fresnel prism 50 are integrally formed. The first substrate 90 and the fresnel prism 50 may be made of the same material, and the process of forming the first substrate 90 and the fresnel prism 50 may be, for example: providing a substrate; and etching one surface of the substrate into a concave-convex structure by using a dry method or a wet method, wherein the concave-convex structure is triangular prism-shaped. On one hand, the first substrate and the Fresnel prism are integrally formed, so that the process can be simplified; on the other hand, if the first substrate and the fresnel prism are separately designed and bonded by means of the optical cement, even if the first substrate and the fresnel prism are made of the same material, since the refractive index of the optical cement is different from that of the first substrate and the fresnel prism, reflection occurs between the interface between the first substrate and the optical cement and the interface between the optical cement and the fresnel prism, so that the amount of light incident into the display panel is small, and the energy utilization rate of the fingerprint recognition light source is low. Therefore, the first substrate and the Fresnel prism are integrally formed, and the energy utilization rate of the fingerprint identification light source is improved.
Fig. 5a is a schematic cross-sectional structure view of another display panel according to an embodiment of the present invention, fig. 5b is a schematic cross-sectional view of a light path for light propagation shown in fig. 5a, and in combination with fig. 5a and fig. 5b, an arrow indicates a light propagation direction, the display panel further includes a quarter-wave plate 22, the quarter-wave plate 22 is located on a side of the polarizer 21 away from the protective cover 30, and the quarter-wave plate 22 and the polarizer 21 form a circular polarizer 20. External light such as sunlight or lamplight is irradiated into the display panel and reflected by components in the display panel to cause glare, and the circular polarizer has an effect of preventing glare. The components in the display panel having a reflection effect on the external light may be, for example, a reflective electrode, a source/drain of a thin film transistor, a metal trace, and the like.
For clarity, the process of anti-glare of circular polarizer 20 will be briefly described below with quarter-wave plate 22 made of calcite: when viewed along the light propagation direction, a beam of unpolarized light (such as sunlight) enters the display panel, the unpolarized light is first converted into linearly polarized light with the polarization direction perpendicular to the absorption axis PP after passing through the polarizer 21, then the linearly polarized light is converted into left-handed circularly polarized light after passing through the quarter-wave plate 22, the left-handed circularly polarized light is reflected by a component (such as a drain electrode of a thin film transistor) in the display panel and then emitted in the reverse direction (i.e. the direction opposite to the direction of incidence in the display panel), then the left-handed circularly polarized light is converted into right-handed circularly polarized light when viewed along the light propagation direction, the right-handed circularly polarized light is converted into linearly polarized light with the polarization direction same as the absorption axis PP after passing through the quarter-wave plate 22, and the linearly polarized light with the polarization direction same as the absorption axis PP is, the circular polarizer 20 has an effect of preventing glare.
Fig. 6 is a schematic cross-sectional structure view of another display panel according to an embodiment of the present invention, as shown in fig. 6, where the direction of an arrow indicates a light propagation direction, the display panel includes: the array substrate 10, the polarizer 21 and the protective cover 30 are sequentially stacked. The protective cover 30 has the function of protecting the display panel from mechanical damage, and performs touch operation on the display panelThe protective cover 30 can be contacted with a finger. The plurality of fingerprint identification units 40 are located on the side of the polarizer 21 away from the protective cover 30. The fingerprint identification light source 60 is located on the side of the end surface S1 of the display panel, the end surface S1 of the display panel is a plane perpendicular to the display panel, and the fingerprint identification light source 60 emits parallel light. The parallel light emitted from the light source 60 is incident in a manner close to being perpendicular to the end surface S1 of the display panel, and specifically, may be incident from the array substrate 10 at an incident angle θ3Angle of refraction of theta4The refractive index of the array substrate 10 is n4According to the formula of the refractive index, the following can be obtained: n isair·sinθ3＝n4·sinθ4. The distance between the surface of the array substrate 10 away from the polarizer 21 and the surface of the protective cover 30 away from the polarizer 21 is d, the distance between the fingerprint identification unit 40 closest to the end surface S1 of the display panel among the plurality of fingerprint identification units 40 and the end surface S1 of the display panel is L1, the distance between the fingerprint identification unit 40 farthest from the end surface S1 of the display panel among the plurality of fingerprint identification units 40 and the end surface S1 of the display panel is L2, and θ is4Satisfies the following conditions:
at this time, the incident light in the protective cover 30 grazes and totally reflects at the interface between the protective cover 30 and the air (corresponding to the valley of the fingerprint), and θ1Satisfies the following conditions: 88 degree<θ1<At 90 deg.. It should be understood that due to the size limitation of the drawing, only two fingerprint identification units L1 and L2 are illustrated in FIG. 6, and a plurality of fingerprint identification units are included in the product.
Fig. 7 is an optical path diagram of total reflection of linearly polarized light at an interface between a protective cover plate and air, and as shown in fig. 6 and 7, an electric field of the linearly polarized light is E1, an electric field E1, an s axis and a p axis are coplanar, an electric field E1 of the linearly polarized light has a parallel component Ep and a horizontal component Es in the directions of the s axis and the p axis, the s axis is perpendicular to an incident plane (paper surface), and after the linearly polarized light is totally reflected at the interface between the protective cover plate and the air, a phase difference between the parallel component Ep and the horizontal component Es is obtained
Satisfies the following conditions:
When the incident light grazes at the interface between the protective cover 30 and the air and is totally reflected, the phase difference between the reflected parallel component Ep and the horizontal component Es
Satisfies the following conditions:
wherein l is a positive integer. The reflected light is linearly polarized light instead of elliptically polarized light in the normal condition, and the linearly polarized light after the total reflection can pass through the polarizer 21 without damage, so that the weakening effect of the polarizer on fingerprint reflected light (fingerprint signals) is eliminated, and the fingerprint identification accuracy is improved. It should be noted that, in fig. 7, the fingerprint identification light source is exemplarily illustrated to be located on the side of the end surface of the display panel, in other embodiments, a plurality of fingerprint identification light sources may be respectively located at different end surfaces of the display panel, which is not limited in the present invention.
Fig. 8 is a schematic structural diagram of a display device according to an embodiment of the present invention, and as shown in fig. 8, a display device 100 according to an embodiment of the present invention includes a display panel according to any embodiment of the present invention, which may be a mobile phone as shown in fig. 8, or a computer, a television, an intelligent wearable device, and the like, and this embodiment is not particularly limited thereto.
It is to be noted that the foregoing is only illustrative of the preferred embodiments of the present invention and the technical principles employed. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious modifications, rearrangements, combinations and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in greater detail by the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the spirit of the present invention, and the scope of the present invention is determined by the scope of the appended claims.
Claims (9)
1. A display panel, comprising:
the array substrate, the polaroid and the protective cover plate are sequentially stacked;
the fingerprint identification units are positioned on one side of the polaroid, which is far away from the protective cover plate;
the Fresnel prism is positioned on one side of the array substrate, which is far away from the protective cover plate;
the fingerprint identification light source is positioned on one side of the Fresnel prism, which is far away from the protective cover plate, and the fingerprint identification light source emits parallel light;
the Fresnel prism is provided with a bottom surface parallel to the polaroid, and parallel light emitted by the fingerprint identification light source is incident in a way of being vertical to the light incident surface of the Fresnel prism; the incident direction of the parallel light emitted by the fingerprint identification light source and the normal of the plane where the polaroid is located form an incident surface, and the incident surface is perpendicular to or parallel to the direction of the absorption axis of the polaroid; parallel light emitted by the fingerprint identification light source passes through the polaroid and then is changed into linearly polarized light, and when the direction of the incident plane is vertical to the direction of the absorption axis of the polaroid, the polarization direction of the linearly polarized light is in the incident plane; when the direction of the incident plane is parallel to the direction of the absorption axis of the polaroid, the polarization direction of the linearly polarized light is vertical to the incident plane;
the refractive index of the protective cover plate is n1The refractive index of the Fresnel prism is n2(ii) a The incident angle of parallel light emitted by the fingerprint identification light source incident to the surface of one side, far away from the array substrate, of the protective cover plate is theta1(ii) a The incident angle of the parallel light emitted by the fingerprint identification light source to the bottom surface of the Fresnel prism isθ2；θ1And theta2Satisfies the following conditions:
2. the display panel according to claim 1, wherein the fresnel prism is a triangular prism, the section of the triangular prism is an isosceles triangle, and the vertex angle of the isosceles triangle is
Satisfies the following conditions:
3. the display panel of claim 1, wherein n is1＝n2。
4. The display panel of claim 1, wherein the display panel further comprises a quarter-wave plate, the quarter-wave plate is located on a side of the polarizer away from the protective cover plate, and the quarter-wave plate and the polarizer form a circular polarizer.
5. The display panel of claim 1, wherein the protective cover is attached to a surface of the polarizer on a side away from the array substrate by a liquid optical adhesive.
6. The display panel of claim 1, wherein the plurality of fingerprint identification units are located on a side of the array substrate away from the polarizer.
7. The display panel of claim 1, wherein the display panel further comprises a first substrate, the first substrate is located between the array substrate and the Fresnel prism, and the plurality of fingerprint identification units are integrated on a surface of the first substrate on a side away from the Fresnel prism.
8. The display panel of claim 7, wherein the first substrate is integrally formed with the Fresnel prism.
9. A display device characterized by comprising the display panel according to any one of claims 1 to 8.
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| CN109725378B (en) * | 2018-02-13 | 2020-03-10 | 华为技术有限公司 | Protective film, method and device for cutting protective film |
| CN108734134A (en) | 2018-05-22 | 2018-11-02 | 京东方科技集团股份有限公司 | Fingerprint identification device |
| KR102532989B1 (en) * | 2018-09-28 | 2023-05-16 | 도요보 가부시키가이샤 | Image display device with fingerprint authentication sensor |
| CN110208982B (en) * | 2019-04-24 | 2021-05-07 | 荣耀终端有限公司 | Liquid crystal display device having a plurality of pixel electrodes |
| CN110188672B (en) * | 2019-05-29 | 2022-02-01 | 京东方科技集团股份有限公司 | Touch display module and electronic equipment |
| CN110659609B (en) * | 2019-09-25 | 2022-09-16 | Oppo（重庆）智能科技有限公司 | Fingerprint matching method and device, electronic equipment and medium |
| CN111025740B (en) * | 2019-12-31 | 2022-05-27 | 厦门天马微电子有限公司 | Display panel and display device |
| CN111126342B (en) * | 2019-12-31 | 2022-10-28 | 厦门天马微电子有限公司 | A display panel and display device |
| CN112230474B (en) * | 2020-10-30 | 2022-09-13 | 厦门天马微电子有限公司 | Display device |
| CN113138482B (en) * | 2021-04-28 | 2022-08-05 | 武汉华星光电技术有限公司 | Display panel and display device |
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