Object texture collection device and terminal equipment

Abstract

The present application discloses a device and terminal equipment for collecting textures of an object, and relates to the field of texture recognition. The device for collecting textures of an object includes: a light source, a light guide plate, a first coupler and an image sensor; the light source is used to emit detection light; the light guide plate is used to propagate the detection light to the first coupler in a total reflection manner, and the light guide plate has a light exit area; the first coupler is arranged close to the light guide surface of the light guide plate, and is used to release the total reflection state of the detection light in the light guide plate when receiving the detection light, and is used to guide the detection light to the light exit area, so that the detection light leaves the light guide plate from the light exit area and propagates to the object to be identified; the image sensor is used to receive the detection light formed after the object to be identified reflects the detection light. The light guide plate propagates the light emitted by the light source in a total reflection manner, and then guides the light to the light exit area through the diffraction deflection of the first coupler, and leaves the light guide plate and reaches the object to be identified, without the need to arrange the light source near the light exit area.

Description

Technical Field

[0001] The present application relates to the field of object texture recognition, and in particular to an object texture collection device and terminal equipment. Background Art

[0002] Optical fingerprint and palm print imaging recognition technology uses optical sensors to collect pattern images and compare them with the system's existing pattern imaging information to make judgments.

[0003] In the related art, the texture recognition imaging device using active light source illumination has good imaging quality and high accuracy of texture acquisition when in use. However, in the above-mentioned texture recognition imaging device using active light source, the light source needs to be configured to be close to the light emitting area, and the light source and the light emitting area need to meet a specific relative position relationship to build a light path for collecting patterns, that is, the relative position of the light source and the light emitting area is relatively specific, which has great structural restrictions and is not conducive to the architecture arrangement of the terminal device when applied to the terminal device. Summary of the invention

[0004] One purpose of the present application is to provide a device for collecting texture of an object, aiming to solve the problem in the prior art that the relative position setting of the light source and the light emitting area in the texture recognition imaging device using an active light source is inflexible.

[0005] To achieve this purpose, the present application embodiment adopts the following technical solutions:

[0006] An object texture collection device, comprising a light source, a light guide plate, a first coupler and an image sensor;

[0007] The light source is used to emit detection light;

[0008] The light guide plate is used to transmit the detection light to the first coupler in a total reflection manner, and the light guide plate has a light exit area;

[0009] The first coupler is disposed on the light guide surface of the light guide plate, and is used to release the total reflection state of the detection light in the light guide plate when receiving the detection light, and is used to guide the detection light to the light exit area, so that the detection light leaves the light guide plate from the light exit area and propagates to the object to be identified; and

[0010] The image sensor is used to receive the detection light formed after the object to be identified reflects the detection light.

[0011] The detection light emitted by the light source is propagated by total reflection through the light guide plate, and then the detection light is guided to the light exit area through the diffraction deflection of the first coupler, and leaves the light guide plate in the light exit area to reach the object to be identified. There is no need to set the light source near the light exit area. When the first coupler decouples the light source from the light exit area, the relative position of the light source and the light exit area is no longer specific, and the position of the light source and the light exit area is more flexible. The recognition area of ​​the terminal device is an area for user operation, usually set at a location that is convenient for the user to touch, rather than at an arbitrary location. In order to ensure that the detection light leaving the light guide plate in the light exit area can be directed to the recognition area of ​​the terminal device, the relative position of the light exit area and the recognition area is relatively specific, and the position selection of the light source of the object texture collection device relative to the light exit area is more flexible, and can be set away from the light exit area and at a location in the terminal device that does not affect the overall architecture.

[0012] In one embodiment, the first coupler has a first coupling surface, and the first coupling surface is disposed in contact with the light guiding surface.

[0013] In one embodiment, the image sensor and the light exit area are respectively located on two opposite sides of the light guide plate.

[0014] In one embodiment, the first coupler is a diffraction grating.

[0015] In one embodiment, the first coupler is a volume holographic grating.

[0016] In one embodiment, the light guide plate further has a side surface which forms a preset angle with the light guide surface, and the detection light emitted by the light source enters the light guide plate from the side surface.

[0017] In one embodiment, a second coupler is provided between the light source and the light guide plate, the second coupler has a second coupling surface that is arranged in contact with the light guide surface, the light source is located on a side of the second coupler away from the light guide plate, and the second coupler is used to guide the detection light emitted by the light source into the light guide plate.

[0018] In one embodiment, the second coupler is a diffraction grating.

[0019] In one embodiment, the second coupler is a volume holographic grating, and the second coupler is disposed in contact with the light guide plate.

[0020] In one embodiment, the first coupler and / or the second coupler has the same refractive index as the light guide plate.

[0021] In one embodiment, the image sensor, the light source and the first coupler are located on the same side of the light guide plate;

[0022] Alternatively, the light source and the light exit area are located on one side of the light guide plate, and the image sensor and the first coupler are located on the other side of the light guide plate.

[0023] In one embodiment, the wavelength range of the detection light emitted by the light source is 665 nanometers-675 nanometers; the refractive index range of the first coupler is 1.45-1.55, the refractive index range of the second coupler is 1.45-1.55, and the refractive index range of the light guide plate is 1.45-1.55.

[0024] In one embodiment, the thickness of the light guide plate is in the range of 0.15 mm to 0.8 mm.

[0025] In one embodiment, a collimator is provided between the light source and the second coupler, and the light source is located at the focus of the collimator.

[0026] In one embodiment, a narrowband filter is provided between the light source and the light guide plate, so that only monochromatic light of the detection light emitted by the light source enters the second coupler. The diffraction grating is selective for wavelength and acts on monochromatic light or quasi-monochromatic light. When the second coupler is a diffraction grating, for example, a volume holographic grating, a monochromatic wave or a quasi-monochromatic wave is obtained through a narrowband filter to ensure that the acquisition device can effectively acquire data.

[0027] In one embodiment, the light source is a coherent light source.

[0028] In one embodiment, the object texture collection device further comprises a total reflection layer bonded to a side of the light guide plate having the light exit area, and the refractive index of the total reflection layer is smaller than the refractive index of the light guide plate.

[0029] Another object of an embodiment of the present application is to provide a terminal device, comprising the object texture collection device described in any of the above embodiments.

[0030] In one embodiment, the terminal device has a display screen having an identification area corresponding to the light exiting area, and the identification area is used to place the object to be identified; the light guide plate is at least partially disposed under the display screen.

[0031] In one embodiment, the terminal device has a side frame, and the light guide plate is at least partially disposed under the side frame;

[0032] The side frame has an identification area corresponding to the light exit area, and the identification area is used to place the object to be identified; or

[0033] The light guide plate is provided with the total reflection layer, the total reflection layer has an identification area corresponding to the light exit area, the identification area is used to place the object to be identified, and the side frame is provided with a first identification hole corresponding to the identification area.

[0034] In one embodiment, the terminal device has a back cover, and the light guide plate is at least partially disposed under the back cover;

[0035] The back cover has an identification area corresponding to the light exit area, and the identification area is used to place the object to be identified; or

[0036] The total reflection layer is provided between the back cover and the light guide plate, the total reflection layer has an identification area corresponding to the light exit area, the identification area is used to place the object to be identified, and the back cover is provided with a second identification hole adapted to the identification area.

[0037] The embodiments of the present application have at least the following beneficial effects: the light emitted by the light source is propagated by total reflection through the light guide plate, and the detection light is then guided to the light exit area through diffraction deflection of the first coupler, and leaves the light guide plate in the light exit area to reach the object to be identified. There is no need to set the light source near the light exit area, the relative position of the light source and the light exit area is no longer specific, and the setting of the position of the light source and the light exit area is more flexible.

[0038] The terminal device using the object texture collection device has a more flexible design of the position of the light source and the light output area, and the light source can be set at a position that has little or no impact on the overall structure and volume of the device, making the internal structure of the terminal device more compact and having a better device appearance. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0040] Figure 1 It is a schematic diagram of the structure of a device for collecting textures of an object in an embodiment of the present application;

[0041] Figure 2 This is a schematic diagram of the structure of a device for collecting textures of an object in one embodiment of the present application;

[0042] Figure 3 This is a schematic structural diagram of a device for collecting texture of an object in another embodiment of the present application;

[0043] Figure 4 This is a schematic structural diagram of a device for collecting texture of an object in yet another embodiment of the present application;

[0044] Figure 5 This is a schematic structural diagram of a device for collecting texture of an object in another embodiment of the present application;

[0045] Figure 6 is a schematic diagram of the diffraction deflection of light in the light guide plate by the first coupler in the embodiment of the present application;

[0046] Figure 7 It is a schematic diagram of the diffraction deflection of light emitted by the light source by the second coupler in the embodiment of the present application;

[0047] Figure 8 This is a schematic diagram of the structure of the device for collecting texture of an object in an embodiment of the present application (when a filter is provided);

[0048] Fig. 9 This is a schematic diagram of the structure of a device for collecting textures of an object in an embodiment of the present application (when the light guide plate has a total reflection layer);

[0049] Fig.10 This is a schematic diagram of the structure of a terminal device in an embodiment of the present application (when the identification area is located on the display screen);

[0050] Fig.11 for Fig.11 A schematic diagram of the structure of a device for collecting textures of an object in a terminal device;

[0051] Fig.12 for Fig.11 A schematic diagram of the structure of a device for collecting textures of an object in a terminal device (when there is a total reflection layer between the display screen and the light guide plate);

[0052] Fig.13 This is a schematic diagram of the structure of the terminal device in the embodiment of the present application (when the side frame is provided with a first identification hole);

[0053] Fig.14 This is a schematic diagram of the structure of the terminal device in an embodiment of the present application (when the identification area is located at the side frame);

[0054] Fig.15 This is a schematic diagram of the structure of the terminal device in the embodiment of the present application (when the rear cover is provided with a second identification hole);

[0055] Fig.16 This is a schematic diagram of the structure of the terminal device in an embodiment of the present application (when the identification area is located at the back cover);

[0056] In the figure:

[0057] 1. Light source; 2. Light guide plate; 201. First light guide surface; 2011. Light exit area; 202. Second light guide surface; 203. Side; 3. First coupler; 4. Image sensor; 5. Second coupler; 6. Collimator; 7. Filter; 8. Total reflection layer; 9. Equipment body; 901. Side frame; 9011. First identification hole; 902. Back cover; 9021. Second identification hole; 10. Detection light; 11. Probe light; 12. Display screen; 13. Third coupler; 100. Object texture acquisition device; 200. Identification area; 300. Object to be identified; 400. Terminal device. DETAILED DESCRIPTION

[0058] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0059] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0060] It should be understood that the orientation or position relationship indicated by terms such as "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0061] In addition, the terms "first", "second", "third", and "fourth" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first", "second", "third", and "fourth" may explicitly or implicitly include one or more of the feature. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0062] The implementation of the present application is described in detail below in conjunction with specific embodiments.

[0063] The object pattern collection device 100 proposed in the embodiment of the present application can be applied to terminal devices such as mobile phones and tablet computers. When in use, the object pattern collection device 100 collects the user's fingerprint or palm print, and compares it with the pattern information stored in the system of the terminal device to determine whether the detected pattern corresponds to the stored pattern, and then determine the user's identity.

[0064] like Figure 1 , Figure 3 and Figure 6 As shown, the embodiment of the present application proposes a device 100 for collecting textures of an object, comprising: a light source 1, a light guide plate 2, a first coupler 3 and an image sensor 4; the light source 1 is used to emit a detection light 10; the detection light 10 emitted by the light source 1 is propagated in the light guide plate 2 in a total reflection manner; the light guide plate 2 generally has two light guide surfaces arranged opposite to each other, and a side surface 203 which is at an angle (for example, 90 degrees) to the two light guide surfaces. The light guide surface has a larger area, and the side surface 203 has a smaller area. The two light guide surfaces define a main body for transmitting light. Among them, one light guide surface (for example, the first light guide surface 201) has a light emitting area 2011, and correspondingly, the other light guide surface (for example, the second light guide surface 202) is parallel or substantially parallel to the first light guide surface 201. The first coupler 3 is arranged close to the second light guide surface 202 of the light guide plate 2. The first light guide surface 201 has a light exit area 2011, and the first coupler 3 is used to release the total reflection state of the detection light 10 in the light guide plate 2 and emit the light exit area 2011 in the light guide plate 2 to the object to be identified 300. The image sensor 4 is used to receive the detection light 11 after the detection light 10 is reflected by the object to be identified 300.

[0065] It can be understood that since the surface texture of the object 300 to be identified has concave and convex parts, and there are differences in the parameters (such as intensity and phase) of the detection light 11 after the detection light 10 is reflected by the concave and convex parts, the image of the texture can be obtained by comprehensive calculation based on parameters such as the intensity and phase of the detection light 11, and then the user's identity and other information can be identified through this.

[0066] It can be understood that the light exit area 2011 is a partial area or the entire area of ​​the first light guiding surface 201 , and the physical properties of the light exit area 2011 may be consistent with other areas of the first light guiding surface 2011 . The position of the first coupler 3 determines the position of the light exit area 2011 .

[0067] In the embodiment of the present application, the object texture collection device 100 collects the object texture in the following process: the detection light 10 emitted by the light source 1 enters the light guide plate 2 and is transmitted in the light guide plate 2. In the light guide plate 2, the detection light 10 is repeatedly projected to the first light guide surface 201 and the second light guide surface 202 at an angle a, and the angle a is greater than the critical angle of total reflection of the light guide plate 2, so that the detection light 10 is transmitted to the first coupler 3 in the light guide plate 2 by total reflection. Figure 1 and 6 As shown, after the detection light 10 reaches the first coupler 3, the first coupler 3 diffracts and deflects the detection light 10, so that the angle between the diffracted light beam and the normal of the second light guide surface 202 of the light guide plate 2 is reduced, thereby making the propagation angle b of the diffracted and deflected detection light 10 smaller than the critical angle of total reflection of the light guide plate 2. Therefore, the light no longer propagates by total reflection in the light guide plate 2 but propagates to the object 300 to be identified through the light exit area 2011 of the first light guide surface 201 on the light guide plate 2. The object 300 to be identified, such as a finger or palm, which has texture, reflects the detection light 10 to form a detection light 11, and the detection light 11 reflected by the object 300 to be identified propagates to the image sensor 4. After the image sensor 4 receives the detection light 11 with texture information, the processor can process the detection light to form a texture image, thereby completing the collection of the texture of the object 300 to be identified.

[0068] Therefore, the object texture collection device 100 provided in the embodiment of the present application transmits the detection light 10 emitted by the light source 1 in a total reflection manner through the light guide plate 2, and then guides the detection light 10 to the light exit area 2011 through the diffraction deflection of the first coupler 3. The detection light 10 leaves the light guide plate 2 from the light exit area 2011 and propagates to the object 300 to be identified. Therefore, there is no need to set the light source 1 near the light exit area 2011, that is, to decouple the light source 1 and the light exit area 2011. When the first coupler 3 decouples the light source 1 from the light exit area 2011, the relative position of the light source 1 and the light exit area 2011 is no longer specific, and the setting of the light source 1 is more flexible, so the components of the terminal can be compactly arranged as needed.

[0069] The total reflection transmission of the light guide plate 2 is based on the condition that total reflection occurs: the light is emitted from the medium with a higher refractive index to the medium with a lower refractive index, and the incident angle of the light is greater than the critical angle. The critical angle, also known as the critical angle of total reflection, refers to the minimum incident angle when total reflection occurs at the interface between the denser medium and the less dense medium when light is incident from the denser medium to the less dense medium.

[0070] In a possible total reflection scheme, such as Figure 1 As shown, the settings of the light source 1 and the light guide plate 2 must meet the above-mentioned conditions for total reflection to occur. After the detection light 10 emitted by the light source 1 is directly refracted into the light guide plate 2 from the side surface 203 of the light guide plate 2, it can be directed toward the first light guide surface 201 of the light guide plate 2 at an angle greater than or equal to the critical angle.

[0071] In another possible total reflection scheme, such as Figure 2As shown, a third coupler 13 is provided between the light source 1 and the side surface 203. The detection light 10 emitted by the light source 1 enters the light guide plate 2 after diffraction and deflection by the third coupler 13. The angle of the detection light 10 entering the light guide plate 2 satisfies the adjustment of the above-mentioned total reflection. Since the third coupler 13 can diffract and deflect the detection light 10 emitted by the light source 1, the relative position and relative angle between the light source 1 and the side surface 203 of the light guide plate 2 are no longer specific. By adjusting the parameters of the third coupler 13, the detection light 10 emitted by the light source 1 at various positions and angles can enter the light guide plate 2 at an angle that satisfies the total reflection condition. This makes the setting of the position of the light source 1 more flexible.

[0072] In another possible total reflection scheme, such as Fig. 9 , a total reflection layer 8 is arranged on the first light guide surface 201 of the light guide plate 2, and the total reflection layer is made of a material with a refractive index less than that of the light guide plate 2, so the angle at which the detection light 10 emitted by the light source 1 enters the light guide plate 2 is greater than the critical angle between the light guide plate 2 and the total reflection layer 8. In this scheme, the refractive index of the total reflection layer 8 is less than the refractive index of the light guide plate 2; the critical angle of the light guide plate 2 relative to the total reflection layer 8 is a, and the angle at which the detection light 10 enters the light guide plate 2 is greater than the critical angle a, so that the detection light 10 does not enter the total reflection layer 8 before passing through the first coupler 3, but propagates to the first coupler 3; after the first coupler 3 deflects and diffracts the detection light 10, the angle at which the detection light 10 is emitted from the light guide plate 2 to the total reflection layer 8 is less than the above critical angle a, so that the detection light 10 after deflection and diffraction by the first coupler 3 can enter the total reflection layer 8 and be projected onto the object to be measured.

[0073] The setting of the total reflection layer 8 allows the recognition area 200 (the area for user operation) to be set on the total reflection layer 8 when the object texture collection device 100 is applied to the terminal device 400, so as to facilitate the placement of the user's fingers and palms. In addition, the total reflection layer 8 can also protect the light guide plate 2.

[0074] The release of the total reflection state of the detection light by the first coupler 3 is mainly based on the deflection coupling of the light by the first coupler 3. The first coupler 3 may include devices such as a diffraction grating. Specifically, the first coupler 3 may be based on Bragg diffraction to deflect and transmit the detection light 10 to the light exit area 2011, and the principle of Bragg diffraction applied in this embodiment is described later.

[0075] In this embodiment, the light guide plate 2 includes a component with low attenuation of light (for example, made of glass material or resin material), so that most of the detection light 10 emitted by the light source 1 can propagate to the first coupler 3 and be diffracted and deflected by the first coupler 3 to the light exit area 2011, and leave the light guide plate 2 from the light exit area 2011 to propagate to the object to be identified 300. This structure makes the detection light 10 reaching the object to be identified 300 strong enough, and then makes the detection light 11 reflected by the object to be identified 300 strong enough, thereby ensuring that the light signal received by the image sensor 4 is strong enough.

[0076] The light intensity of the light source 1 is adjustable. For example, the light intensity of the light source 1 can be adjusted according to the different paths along which the light propagates in the light guide plate 2. By adjusting the light intensity of the light source 1, even when the light guide plate 2 has light loss, the light intensity reaching the object to be identified 300 can be sufficient, so that the light reflected by the object to be identified 300 and reaching the image sensor 4 is sufficient to enable the image sensor 4 to accurately capture the texture image of the object to be identified 300.

[0077] See also Figure 1-Figure 3 , the first coupler 3 has a first coupling surface, and the first coupling surface is in contact with the second light guide surface 202 of the light guide plate 2. The position of the first coupler 3 can be flexibly adjusted according to the position of the light exit area 2011. Compared with the solution of integrating the first coupler 3 into a fixed position in the light guide plate 2, the position of the aforementioned coupler 3 can be flexibly adjusted according to the needs of installation. For example, when there is no other medium between the light guide plate 2 and the first coupler 3 (when the first coupler 3 is a photopolymer with a certain viscosity, such as a photopolymer based on propylene trimer, the first coupler 3 can be bonded to the light guide plate 2 without the need for bonding with an external medium such as glue), when the detection light 10 passes between the light guide plate 2 and the first coupler 3, the propagation angle is changed only by the effect of the refractive index difference between the light guide plate 2 and the first coupler 3. When designing the detection optical path, between the light guide plate 2 and the first coupler 3, only the refractive index parameters of the light guide plate 2 and the first coupler 3 themselves need to be considered, which can simplify the design of the detection optical path. Furthermore, the light guide plate 2 and the diffraction grating in the first coupler 3 are made of the same material, and there is no refraction when the detection light 10 enters the first coupler 3 from the light guide plate 2 (after the light enters the first coupler 3, it is deflected by the diffraction grating in the first coupler 3), and there is no refraction between the two, which can further simplify the optical path design and structural design.

[0078] See also Figure 1-Figure 3In one embodiment, the image sensor 4 and the light exit area 2011 are respectively located on opposite sides of the light guide plate 2. When the light diffracted and deflected by the first coupler 3 propagates through the light exit area 2011 on the first light guide surface 201 to the object to be identified 300, the object to be identified 300 reflects the light, and the reflected light passes through the light guide plate 2 to reach the image sensor 4. For example, the image sensor 4 and the light exit area 2011 can be respectively located on opposite sides of the light guide plate 2 and are substantially facing each other.

[0079] The light source 1, the light guide plate 2, the first coupler 3 and the image sensor 4 in the embodiment of the present application can be arranged in the following two ways but are not limited to:

[0080] Figure 1 This is an example of the first method. Figure 1 In the figure, the image sensor 4 , the light source 1 and the first coupler 3 are located on the side of the second light guide surface 202 of the light guide plate 2 .

[0081] In this embodiment, the detection light 10 emitted by the light source 1 enters the light guide plate 2 and propagates to the first coupler 3 in a total reflection manner. The first coupler 3 on the same side of the light source 1 deflects and diffracts the detection light 10 to the light exit area 2011. The detection light 10 leaves the light guide plate 2 in the light exit area 2011 and propagates to the object 300 to be identified located in the identification area 200. That is, in the terminal device 400, the light exit area 2011 and the identification area 200 are located on the same side of the light guide plate 2. When the object texture acquisition device 100 is applied to the terminal device 400, the image sensor 4, the light source 1 and the first coupler 3 located on the same side of the light guide plate 2 may be located inside the terminal device 400; Fig.10 and Figure 14-16 As shown, the identification area 200 may be located outside the terminal device 400 , such as the display screen 12 , the side frame 901 , and the back cover 902 .

[0082] Figure 3 This is an example of the second method. Figure 3 In the figure, the light source 1 and the light emitting area 2011 are located on the side of the first light guide surface 201, and the image sensor 4 and the first coupler 3 are located on the side of the second light guide surface 202 of the light guide plate 2. When the device 100 for collecting textures of an object is applied to a notebook with a backlit keyboard, the backlight light source of the backlit keyboard can realize the function of the above-mentioned light source 1 to emit detection light 10 (for example, the backlight light source of the notebook can transmit the light used for display to the keys through the light guide component, and the backlight light source can also provide detection light 10 to the light guide plate 2). That is, the light source 1 can be used as a part of the backlit keyboard, and the identification area 200 can be set on the surface of the notebook. At this time, the light source 1 and the identification area 200 are located on the side of the first light guide surface 201, and the image sensor 4 and the first coupler 3 are located on the side of the second light guide surface 202.

[0083] In all embodiments of the present application, the first coupler 3 may be a diffraction grating. The diffraction grating is small in size and can meet the requirements of mobile phones for miniaturization of components. Specifically, the first coupler 3 may be a volume holographic grating.

[0084] In the embodiment of the present application, the first coupler 3 deflects and transmits the detection light 10 based on the diffraction effect to destroy its total reflection state, transmits it to the light exit area 2011, and then leaves the light guide plate 2 through the light exit area 2011 to reach the object to be identified 300. The structure and optical parameters of the first coupler 3 can be determined based on the Bragg diffraction condition. Specifically, refer to Figure 6 The diffraction of electromagnetic waves by a medium with a refractive index modulation period can be regarded as the coherent superposition of the reflections of electromagnetic waves by multiple crystal planes. If the reflections between different crystal planes are exactly an integer multiple of the wavelength, the coherence is enhanced. This coherence enhancement condition is called the Bragg condition, that is: 2d 1 sinθ B1 =m 1 λ 1 , where m 1 is an integer, 1 is taken for ease of calculation, λ 1 To detect the wavelength of light 1 in the first coupler 3, λ 1 =λ / n 1 , n 1 is the refractive index of the first coupler 3; and then 2d 1 sinθ B1 =λ / n 1 At the same time, when the incident angle θ B1 When the incident angle θ is equal to the reflection angle Y1 (diffraction angle), the Bragg condition is met. The incident angle at this time is also called the Bragg angle. B1 It refers to the light beam relative to the plane perpendicular to the refractive index modulation period, rather than relative to the medium surface.

[0085] On this basis, for example, Figure 6 As shown, if the refractive index of the light guide plate 2 is 1.5 and the refractive index of the air in contact with the surface of the light guide plate 2 is 1, then the critical angle of the light guide plate 2 relative to the air is 41.8°; the angle θ at which the detection light 10 emitted by the light source 1 propagates in the light guide plate 2 is selected. out The angle is 60°, which satisfies the total reflection condition, so that the detection light 10 is propagated to the first coupler 3 in a total reflection manner in the light guide plate 2 .

[0086] In order to simplify the calculation, the refractive index of the first coupler 3 is selected to be the same as that of the light guide plate 2, for example, both are 1.5. At the same time, in order to destroy the total reflection condition of the detection light 10 in the light guide plate 2, the first coupler 3, i.e., the volume holographic grating, is selected to diffract and deflect the light into the light guide plate 2 at an angle θ LThe angle is 30°, so that the light can be emitted from the light guide plate 2 to reach the light exit area 2011, and then leave the light guide plate 2 in the light exit area 2011 and illuminate the object 300 to be identified.

[0087] Assume that the wavelength of the detection light 10 emitted by the light source 1 is 670 nanometers. Figure 6 As shown, θ out is 60°, θ L is 30°, at this time the incident angle = diffraction angle = 45°, it can be confirmed that the wave vector of the first coupler 3 The direction of the medium surface is at an angle θ K1 is 15°, the refractive index modulation period direction is related to the wave vector The directions are perpendicular to each other, that is, the angle with the medium surface is 75°. According to the Bragg condition 2d 1 sinθ B1 =λ / n 1 ,θ B1 is the Bragg angle, i.e. 45°, λ is the wavelength of the detection light 10 emitted by the light source 1, which is 670nm, and n 1 is the refractive index of the first coupler 3, which is 1.5, d 1 is the refractive index modulation period of the first coupler 3, and then the refractive index modulation period d of the first coupler 3 is obtained 1 It is 314.42 nanometers.

[0088] It can be understood that according to the above Bragg conditions, when the wavelength, the incident angle and the diffraction angle are determined, the refractive index modulation period d of the first coupler can be determined. 1 Of course, any of these parameters can be determined by calculating other parameters, and then the corresponding structure and optical parameters can be determined according to the design of the optical path.

[0089] On this basis, when a total reflection layer 8 is provided on the light guide plate 2, in order to make the detection light 10 (whose incident angle is angle θ) entering the light guide plate 2 after diffraction and deflection by the first coupler 3 L 30°) can be emitted to the total reflection layer 8 without total reflection. It is necessary to make the critical angle θ of the light guide plate 2 relative to the total reflection layer 8 临 is greater than 30°, and in order to ensure that the detection light 10 is totally reflected during the propagation of the detection light 10 to the first coupler 3, the critical angle θ of the light guide plate 2 relative to the total reflection layer 8 is 临 Less than 60°, assuming that the refractive index of the total reflection layer 8 is n 3 The conditions for total reflection of light are: n 1 sinθ 临 =n 3 sin90°, when θ 临 When it is greater than 30° and less than 60°, then n1 is the refractive index of the first coupler 3 and is 1.5, so 0.75<n 3 <1.29. Optionally, the first coupler 3 is a volume holographic grating formed by a photopolymer film, such as an acrylate-based photosensitive polymer, with a refractive index of 1.5.

[0090] It can be understood that the above θ out is 60°, θ L 30° and wavelength of 670 nanometers are optional data. out is the angle at which total reflection can occur, θ L An angle of 30° is sufficient to disrupt total reflection.

[0091] See also Figure 1 As a way for the detection light 10 emitted by the light source 1 to enter the light guide plate 2, the detection light 10 emitted by the light source 1 enters the light guide plate 2 from the side surface 203 of the light guide plate 2. The light output angle of the light source 1 is adjusted so that after the detection light 10 emitted by the light source 1 is refracted through the side surface 203 and enters the light guide plate 2, the detection light 10 is repeatedly projected onto the first light guide surface 201 and the second light guide surface 202 at an angle a, and the angle a is greater than the critical angle of total reflection of the light guide plate 2, so that the detection light 10 propagates toward the first coupler 3 in the light guide plate 2 in a total reflection manner.

[0092] The side surface 203 and the light guiding surface (the first light guiding surface 201 or the second light guiding surface 202 ) are at a preset angle. For example, the side surface 203 may be perpendicular to the light guiding surface.

[0093] See also Figure 3-Figure 4 , as a way for the detection light 10 emitted by the light source 1 to enter the light guide plate 2: a second coupler 5 is provided between the light source 1 and the light guide plate 2, and the second coupler 5 has a second coupling surface that is arranged in contact with the light guide surface (the first light guide surface 201 or the second light guide surface 202), and the second coupler 5 is used to guide the detection light 10 emitted by the light source 1 into the light guide plate 2. The detection light 10 emitted by the light source 1 enters the second coupler 5, and the second coupler 5 diffracts and deflects the detection light 10, so that the detection light 10 enters the light guide plate 2 through the first light guide surface 201 or the second light guide surface 202 and then undergoes total reflection in the light guide plate 2. That is, the light emitted by the light source 1 can be diffracted and deflected by the second coupler 5, and the detection light 10 that enters the light guide plate 2 after diffraction and deflection undergoes total reflection in the light guide plate 2. Therefore, when the light source 1 is set, no specific installation angle and installation position are required, making the setting of the light source 1 more flexible.

[0094] As an embodiment of the second coupler 5, see Figure 7 The second coupler 5 may also be a diffraction grating. The diffraction grating is relatively small in size and can meet the requirements of mobile phones for miniaturization of components.

[0095] Specifically, the second coupler 5 is a volume holographic grating, and the second coupler 5 is arranged in contact with the light guide plate 2. In order to simplify the design, the second coupler 5 has the same working principle as the first coupler 3 and is made of the same material.

[0096] For example, Figure 7 As shown, the refractive index of the light guide plate 2 is 1.5, and the refractive index of the air in contact with the surface of the light guide plate 2 is 1, then the critical angle of the light guide plate 2 relative to the air is 41.8°; the angle θ at which the light source 1 propagates in the light guide plate 2 is selected. out It is 60°, which can meet the total reflection condition.

[0097] In order to simplify the calculation, the refractive index of the second coupler 5 is selected to be the same as that of the light guide plate 2, for example, both are 1.5. Then the diffraction light I formed by the diffraction of the light by the second coupler 5 is diff Direction and I diff The detection light I formed by entering the light guide plate 2 from the second coupler 5 out The same direction. According to I diff with I out The direction of the diffracted light I diff The angle between the normal direction of the second light guide surface 202 of the light guide plate 2 is 60°, and the detection light I formed by entering the light guide plate 2 from the second coupler 5 out The included angle with the normal direction of the second light guiding surface 202 of the light guiding plate 2 is also 60°.

[0098] Therefore, according to Figure 7 As shown, the incident angle θ of the detection light 10 relative to the second coupler 5 is B2 and the diffraction angle Y2 is 30°. Assuming that the wavelength λ of the detection light 10 emitted by the light source 1 is 670 nanometers, the second coupler 5 satisfies the Bragg condition when generating diffracted light, that is: 2d 2 sinθ B2 =m 2 λ 2 , where m 2 is an integer, 1 is taken for ease of calculation, λ 2 To detect the wavelength of light 1 in the first coupler 3, λ 2 =λ / n 1 , n 2 is the refractive index of the second coupler 5; and then 2d 2 sinθ B2 =λ / n 2 ,θ B2 is the Bragg angle, which is 30°, λ is the wavelength of the detection light 10 emitted by the light source 1, which is 670 nanometers, and n 2 is the refractive index of the second coupler 5, which is 1.5, d 2is the refractive index modulation period of the second coupler 5, and the Bragg angle θ B2 is 30°, and the refractive index modulation period d of the second coupler 5 is obtained. 2 is 447 nanometers.

[0099] Optionally, the second coupler 5 is a volume holographic grating formed by a photopolymer film, such as an acrylate-based photosensitive polymer with a refractive index of 1.5.

[0100] In the embodiment of the present application, under the condition that the detection light 10 emitted by the light source 1 propagates in the light guide plate 2 in a total reflection manner and is released from the total reflection at the first coupler 3, the wavelength range of the detection light 10 emitted by the light source 1 can be 665 nanometers-675 nanometers, the refractive index range of the first coupler 3 can be 1.45-1.55, the refractive index range of the second coupler 5 can be 1.45-1.55, and the refractive index range of the light guide plate 2 can be 1.45-1.55. The thickness range of the light guide plate 2 can be 0.15 mm-0.8 mm, so that different terminal devices 400 can be selected.

[0101] See also Figure 5 Optionally, a collimator 6 is provided between the light source 1 and the second coupler 5, and the light source 1 is located at the focus of the collimator 6. The light source 1 emits the detection light 10 at the focus of the collimator 6, and the collimator 6 can collimate the detection light 10 with low parallelism, so that the detection light 10 can enter the second coupler 5 in a direction perpendicular to the surface of the second coupler 5, and the second coupler 5 diffracts and deflects the detection light 10 and then emits it into the light guide plate 2.

[0102] The detection light 10 enters the second coupler 5 in a direction perpendicular to the surface of the second coupler 5 , which can facilitate setting of parameters such as the refractive index and the refractive index modulation period of the second coupler 5 .

[0103] See also Figure 8 Optionally, a narrowband filter 7 is provided between the light source 1 and the second coupler 5, so that only monochromatic light or quasi-monochromatic light of the detection light 10 emitted by the light source 1 enters the second coupler 5. The diffraction grating is selective for wavelength and acts on monochromatic light or quasi-monochromatic light. When the second coupler 5 is a diffraction grating, for example a volume holographic grating, a monochromatic wave or a quasi-monochromatic wave is obtained through the narrowband filter 7 to ensure that the acquisition device 100 can effectively acquire data.

[0104] For example, in all embodiments of the present application, the light source 1 may be a coherent light source 1 , that is, the detection light 10 generated by the light source 1 is coherent light, and in this case, there is no need to set a narrow-band filter 7 .

[0105] For example, in all embodiments of the present application, the first coupler 3 and the second coupler 5 can both be volume holographic diffraction gratings to achieve diffraction deflection of the detection light 10. The volume holographic grating can be dichromate, silver halide emulsion, dichromate gelatin, photoresist, photopolymer, photothermal plastic, photorefractive crystal, liquid crystal, etc. as a recording medium. The recording medium can produce a refractive index change under a specific wavelength of illumination light. The thickness varies from about 20μm, and the refractive index modulation degree varies from about 0.03. After the original holographic recording material is holographically exposed, a volume grating structure with a periodic change in the refractive index is formed to achieve diffraction deflection of the incident light beam.

[0106] The following is a design example when the second coupler 5 is a volume holographic grating:

[0107] See also Figure 7 , I in To detect the light angle when the light 10 enters the second coupler 5, I diff is the light angle formed by the second coupler 5 diffracting the detection light 10, I out is the light angle when the detection light 10 enters the light guide plate 2.

[0108] in I out The direction is certain, I diff with I out Satisfy the law of refraction (n 4 sinθdiff=n 5 sinθout), n 4 is the refractive index of the second coupler 5, n 5 is the refractive index of the light guide plate 2. Thus, the refractive index of the second coupler 5 and the light guide plate 2 can be determined. diff direction.

[0109] Therefore, according to the wave vector of the incident light and the wave vector of the diffracted light The wave vector of the second coupler 5 can be obtained The second coupler 5 is a volume holographic grating, which can be obtained by interference of two light beams. Assume that the wave function expression of the two light beams is and When coherent on the holographic recording material, the light intensity distribution is in The wave vector of the second coupler 5 The wave vectors of the two light beams can be obtained and Thus, the design method of the holographic volume grating coupling device can be determined, and then the second coupler 5 can be designed according to different usage requirements. The design method of the first coupler 3 when it is a volume holographic grating is the same as the design method of the second coupler 5, which will not be repeated here.

[0110] like Fig.10 As shown, an embodiment of the present application proposes a terminal device 400, including a device body 9 and an object texture collection device 100 in any of the above embodiments, and the object texture collection device 100 is installed on the device body 9.

[0111] The device body 9 can be an electronic device such as a mobile phone or a tablet computer. The identification area 200 can be located on the surface of the terminal device 400, so as to facilitate the identification of biometric information such as fingerprints or palm prints of the user. When the user holds the terminal device 400, the pattern collection can be completed conveniently, and the processor of the terminal device 400 can compare it with the reserved correct pattern information. If the collected pattern information matches the reserved one, the unlocking, payment and other functions of the terminal device 400 are completed.

[0112] The light source 1 , the first coupler 3 , the second coupler 5 and the image sensor 4 may all be disposed inside the terminal device 400 .

[0113] See also Figure 10-12 As another specific implementation of the terminal device 400 provided in the present application, a display screen 12 is provided on the device body 9, and the identification area 200 is located on the display screen 12; the light guide plate 2 is at least partially arranged under the display screen 12 (when the display screen 12 is a liquid crystal display screen, the light guide plate 2 can also be the light guide plate of the display screen 12 itself).

[0114] like Fig.12 As shown, the identification area 200 is set on the display screen 12. When the user holds the terminal device 400, the finger can press the identification area 200 on the display screen 12 of the terminal device 400, so that the fingerprint collection is completed quickly. The detection light 10 emitted by the light source 1 is transmitted from the light guide plate 2 to the first coupler 3. The first coupler 3 deflects and diffracts the detection light 10 at the light exit area 2011, passes through the light guide plate 2 and the total reflection layer 8 (if the total reflection layer 8 is not provided, the detection light 10 passes through the light guide plate 2 and directly reaches the display screen 12), and then passes through the display screen 12 to reach the identification area 200 on the surface of the display screen 12 to the object to be identified 300. The object to be identified 300 reflects the light, and the detection light 10 is reflected to form a detection light 11 that passes through the display screen 12, the total reflection layer 8 (if the total reflection layer 8 is not provided, the detection light 11 directly reaches the light guide plate 2) and the light guide plate 2, and finally reaches the image sensor 4.

[0115] In one embodiment of the present application, when the display screen 12 is a liquid crystal display screen, the light guide plate of the display screen 12 itself can realize the function of the above-mentioned light guide plate 2 for transmitting the detection light 10. In this embodiment, there is no need to set up an additional light guide plate 2.

[0116] When a total reflection layer 8 is provided, foreign matter or loose components can be prevented from reaching between the display screen 12 and the light guide plate 2, thereby preventing the detection light 10 in the light guide plate 2 from being released from total reflection before reaching the first coupler 3, thereby preventing the detection light 10 from failing to reach the first coupler 3 and being deflected and diffracted by the first coupler 3 before reaching the identification area 200, so that sufficient light is transmitted to the identification area 200.

[0117] The identification area 200 can be set at any position of the display screen 12. The detection light 10 emitted by the light source 1 is guided to the first coupler 3 by the light guide plate 2 and deflected and diffracted to the light exit area 2011, and then leaves the light guide plate 2 from the light exit area 2011 and reaches the identification area 200; at the same time, according to the amount of light loss when the detection light 10 propagates in the light guide plate 2, the intensity of the detection light 10 emitted by the light source 1 is adjusted to ensure that the detection light 10 reaching the identification area 200 is strong enough.

[0118] See also Fig.14 As another specific implementation of the terminal device 400 provided in the present application, the device body 9 has a side frame 901, the light guide plate 2 is at least partially located under the side frame 901, and the identification area 200 is located on the side frame 901.

[0119] When the terminal device 400 cannot be equipped with enough components directly below the display screen 12 for reasons such as a more compact internal structure, the light source 1, light guide plate 2 (when the display screen 12 is a liquid crystal display screen, it is different from the light guide plate of the display screen 12), first coupler 3 and image sensor 4 of the object texture collection device 100 can be placed near the frame 901 in the terminal device 400. An area with sufficient light transmittance is set on the side frame 901 to form the identification area 200.

[0120] like Fig.13 As shown, when the light guide plate 2 (when the display screen 12 is a liquid crystal display screen, it is different from the light guide plate of the display screen 12) is provided with a total reflection layer 8, the identification area 200 can also be located on the total reflection layer 8, and the side frame 901 is provided with a first identification hole 9011 corresponding to the identification area 200, so that a finger can be inserted and contact the identification area 200 on the total reflection layer 8. Fig.16 As another specific implementation of the terminal device 400 provided in the present application, the device body 9 has a back cover 902 , the light guide plate 2 is at least partially located under the back cover 902 , and the identification area 200 is located on the back cover 902 .

[0121] Part or most of the back cover 902 has a material with sufficient light conductivity to form the identification area 200. Fig.15As shown, when a total reflection layer 8 is provided on the light guide plate 2, the identification area 200 may also be located on the total reflection layer 8, and the back cover 902 is provided with a second identification hole 9021 adapted to the identification area 200 for a finger to be inserted into and contact with the identification area 200 on the total reflection layer 8.

[0122] Obviously, the above embodiments of the present application are only examples for clearly illustrating the present application, and are not intended to limit the implementation methods of the present application. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all implementation methods here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present application should be included in the protection scope of the claims of the present application.

Claims

1. A device for collecting texture of an object, characterized in that: comprising a light source, a light guide plate, a first coupler and an image sensor; The light source is used to emit detection light; The light guide plate is used to transmit the detection light to the first coupler in a total reflection manner, and the light guide plate has a light exit area; The first coupler is disposed on the light guide surface of the light guide plate, and is used to release the total reflection state of the detection light in the light guide plate when receiving the detection light, and is used to guide the detection light to the light exit area, so that the detection light leaves the light guide plate from the light exit area and propagates to the object to be identified; as well as An image sensor is used to receive detection light formed after the object to be identified reflects the detection light; The first coupler is disposed outside the light guide plate, and the position of the first coupler on the light guide surface of the light guide plate can be adjusted according to the position of the light exit area.

2. The device for collecting texture of an object according to claim 1, characterized in that: A second coupler is provided between the light source and the light guide plate, the second coupler having a second coupling surface that is arranged in contact with the light guide surface, the light source is located on a side of the second coupler away from the light guide plate, and the second coupler is used to deflect the detection light and guide it into the light guide plate.

3. The device for collecting texture of an object according to claim 2, characterized in that: The second coupler is a diffraction grating.

4. The device for collecting texture of an object according to claim 3, characterized in that: The second coupler is a volume holographic grating.

5. The device for collecting texture of an object according to claim 2, characterized in that: The first coupler and / or the second coupler has / have the same refractive index as the light guide plate.

6. The device for collecting texture of an object according to claim 2, characterized in that: The image sensor, the light source and the first coupler are located on the same side of the light guide plate; Alternatively, the light source and the light exit area are located on one side of the light guide plate, and the image sensor and the first coupler are located on the other side of the light guide plate.

7. The device for collecting texture of an object according to claim 1, characterized in that: The light guide plate further has a side surface which forms a preset angle with the light guide surface, and the detection light emitted by the light source enters the light guide plate from the side surface.

8. The device for collecting texture of an object according to claim 7, characterized in that: A third coupler is disposed between the light source and the side surface, and the third coupler has a third coupling surface that is disposed in close contact with the side surface.

9. The device for collecting texture of an object according to any one of claims 1 to 8, characterized in that: The first coupler has a first coupling surface, and the first coupling surface is disposed in contact with the light guiding surface.

10. The device for collecting texture of an object according to any one of claims 1 to 8, characterized in that: The image sensor and the light exit area are respectively located on two opposite sides of the light guide plate.

11. The device for collecting texture of an object according to any one of claims 1 to 8, characterized in that: The first coupler is a diffraction grating.

12. The device for collecting texture of an object according to any one of claims 1 to 8, characterized in that: The first coupler is a volume holographic grating.

13. The device for collecting texture of an object according to any one of claims 1 to 8, characterized in that: The thickness of the light guide plate ranges from 0.15 mm to 0.8 mm.

14. The device for collecting texture of an object according to any one of claims 2 to 6, characterized in that: A collimator is provided between the light source and the second coupler, and the light source is located at the focus of the collimator.

15. The device for collecting texture of an object according to any one of claims 1 to 8, characterized in that: The light source is a coherent light source; or, the light source is an incoherent light source, and a narrow-band filter is provided between the light source and the light guide plate.

16. The device for collecting texture of an object according to any one of claims 1 to 8, characterized in that: The object texture collection device also includes a total reflection layer that is bonded to a side of the light guide plate having the light exit area, and the refractive index of the total reflection layer is smaller than the refractive index of the light guide plate.

17. A terminal device, characterized in that A device for collecting texture of an object comprising the device as described in any one of claims 1-16.

18. The terminal device according to claim 17, characterized in that: The terminal device has a display screen, the display screen has an identification area corresponding to the light exit area, and the identification area is used to place the object to be identified; the light guide plate is at least partially arranged under the display screen.

19. The terminal device according to claim 17, characterized in that: The terminal device has a side frame, and the light guide plate is at least partially arranged under the side frame; The side frame has an identification area corresponding to the light exit area, and the identification area is used to place the object to be identified; or The light guide plate is provided with a total reflection layer, the total reflection layer has an identification area corresponding to the light exit area, the identification area is used to place the object to be identified, and the side frame is provided with a first identification hole corresponding to the identification area.

20. The terminal device according to claim 17, characterized in that: The terminal device has a back cover, and the light guide plate is at least partially arranged under the back cover; The back cover has an identification area corresponding to the light exit area, and the identification area is used to place the object to be identified; or A total reflection layer is provided between the back cover and the light guide plate, the total reflection layer has an identification area corresponding to the light exit area, the identification area is used to place the object to be identified, and the back cover is provided with a second identification hole adapted to the identification area.

Images