CN111222497A

CN111222497A - Electronic equipment with under-screen infrared biosensor

Info

Publication number: CN111222497A
Application number: CN202010150553.0A
Authority: CN
Inventors: 傅同龙; 王伟榕; 周正三
Original assignee: Egis Technology Inc
Current assignee: Egis Technology Inc
Priority date: 2019-09-16
Filing date: 2020-03-06
Publication date: 2020-06-02
Also published as: CN111208665A; CN211207353U; TWM595259U; WO2021051752A1; TW202113570A; TWI730658B; TWM595251U; CN213240740U; TWI725761B; WO2021051753A1; TW202113433A

Abstract

The invention provides electronic equipment with an in-screen infrared biosensor, which comprises a backlight module, a display panel, a light-transmitting protective plate, an optical sensor and an infrared light source. The backlight module provides visible light to move upwards and is provided with a reflecting layer for blocking the visible light to move downwards. The display panel is arranged above the backlight module and displays information according to the visible light. The light-transmitting protective plate is arranged above the display panel and allows information to penetrate through. The optical sensor is arranged below the backlight module. An infrared light source provides infrared light to a biological body located on or over a light transmissive protective plate. The organism reflects infrared light to generate reflected infrared light, and the reflected infrared light is received by the optical sensor through the light-transmitting protection plate, the display panel and the backlight module, so that the optical sensor obtains an image signal representing the image of the organism, and the in-screen image sensing function is realized.

Description

Electronic equipment with under-screen infrared biosensor

Cross-referencing

U.S. provisional application 62/900,812, entitled "IR LEDLIGHTING INTEGRATED WITH LGP IN LCD FOD SOLUTION," filed 2019, 9, 16, 119 and filed No. 35u.s.c. § 119; U.S. provisional APPLICATION 62/940,445, entitled "LGP FINGERPRINT APPLICATION rule", filed 11/26.2019, and incorporated herein by reference.

Technical Field

The present invention relates to an electronic device with an in-screen infrared biosensor, and more particularly, to an electronic device with an in-screen infrared biosensor, which can be applied to a Liquid Crystal Display (LCD) and an OLED, and a backlight module applied to a Display panel.

Background

Today's mobile electronic devices (e.g., mobile phones, tablet computers, notebook computers, etc.) are usually equipped with user biometric systems, including various technologies such as fingerprints, facial shapes, irises, etc., for protecting personal data security, wherein the mobile payment device is applied to a mobile device such as a mobile phone or an intelligent watch, and has a mobile payment function, the biometric identification of the user becomes a standard function, and the development of portable devices such as mobile phones is more toward the trend of full screen (or ultra-narrow frame), so that the conventional capacitive fingerprint keys (for example, the keys from iphone 5 to iphone 8) can no longer be used, and a new miniaturized optical imaging device (very similar to the conventional camera module, having a Complementary Metal-Oxide Semiconductor (CMOS) Image Sensor and an optical lens module) is developed. The miniaturized optical imaging device is disposed under a screen (referred to as under the screen), and can capture an image of an object pressed on the screen, particularly a Fingerprint image, through partial Light transmission of the screen (particularly an Organic Light Emitting Diode (OLED) screen), which can be referred to as under-screen Fingerprint sensing (FOD).

Conventional optical biosensors (e.g., fingerprint sensors) include an optical module having a CMOS Image Sensor (CIS) chip or module and a Lens array module (Lens array module), which are mainly disposed under an OLED display. Since the OLED display itself transmits light, there is no problem in implementation.

But besides OLED screens, many products also use LCD screens, also OLED screens are evolving, e.g. low penetration screens (penetration from 3% to 1%), which require new underscreen optical fingerprint solutions. The present disclosure is directed to designing an infrared optical sensor module under a Liquid Crystal Display (LCD), or a low-transmittance OLED, or a different screen in the future. This requires a number of challenges. For example, an LCD includes a backlight module, a brightness enhancement film, and a light guide plate, and RGB visible light enters from the side and then diffuses from the light guide plate and the brightness enhancement film to homogenize or blur the light. The light guide plate and the brightness enhancement film are provided with a plurality of sawtooth structures to scatter light to various directions. If the CIS module is placed under the brightness enhancement film and the light guide plate of the backlight module, an Anti-Reflection Coating (ARC) is formed in the backlight module to allow visible light to be totally reflected, so that the visible light reflected by the finger cannot penetrate through the CIS module to reach the CIS module, thereby causing image sensing problems.

Another problem to be solved in the present disclosure is that, for example, in OLED displays, the resolution is higher and higher, and visible FOD is limited by the lower and lower visible light transmittance (higher and higher resolution) of the display, so that the Signal-to-Noise Ratio (SNR) of the visible light of the sensor is lower and lower, and therefore, the FOD scheme by IR can also solve the problem. Of course, other display technologies, such as Micro Light Emitting Diode (led) displays, etc., are also suitable for this solution.

Disclosure of Invention

Therefore, an object of an embodiment of the present invention is to provide an electronic device with an in-screen infrared biosensor and a backlight module applied to a display panel, wherein the electronic device has functions of information display and biological sensing.

To achieve the above objective, an embodiment of the present invention provides an electronic device, which at least includes a backlight module, a display panel, a transparent protection plate, an optical sensor and an infrared light source. The backlight module provides visible light to move upwards and is provided with a reflecting layer for blocking the visible light to move downwards. The display panel is arranged above the backlight module and displays information according to the visible light. The light-transmitting protective plate is arranged above the display panel and allows information to penetrate through. The optical sensor is arranged below the backlight module. The infrared light source provides infrared light to an organism located on or over the light transmissive protective plate. The organism reflects infrared light to generate reflected infrared light, and the reflected infrared light is received by the optical sensor through the light-transmitting protection plate, the display panel and the backlight module, so that the optical sensor obtains an image signal representing an image of the organism, and the in-screen image sensing function is realized.

In addition, the present invention also provides an electronic device, at least comprising: a display panel, which provides visible light to move upwards and displays information according to the visible light; a transparent protective plate arranged above the display panel to allow information to penetrate through; an optical sensor disposed below the display panel; and an infrared light source for providing infrared light to a living body on or above the transparent protective plate, wherein the living body reflects the infrared light to generate reflected infrared light, and the reflected infrared light is received by the optical sensor through the transparent protective plate and the display panel, so that the optical sensor obtains an image signal representing an image of the living body.

The invention further provides a backlight module applied to the display panel, which at least comprises a light guide plate and a visible light source. The light guide plate is matched with an infrared light source to generate infrared light. The visible light source is arranged on one side of the light guide plate and emits light rays which enter the light guide plate to travel so as to generate visible light. Thereby providing the required light for information display and biological sensing.

By the embodiment, the optical sensing module arranged below the LCD can obtain a good biological characteristic image by utilizing infrared light without influencing the display function of the LCD, the reflecting layer of the LCD has different characteristics for infrared light and visible light, so that the reflecting layer which can not be penetrated by the visible light can be penetrated by the infrared light, the infrared light reflected by fingers can easily penetrate the reflecting layer to reach the optical sensor arranged below the reflecting layer, the biological characteristic sensing function is achieved, and an optical biological sensing scheme is provided for an electronic device provided with the LCD. Besides being suitable for LCD displays, the sensor is also suitable for optical biological sensing occasions of other displays such as OLED displays.

In order to make the invention more comprehensible, preferred embodiments accompanied with figures are described in detail below.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts. In the drawings:

FIG. 1 is a schematic diagram of an electronic device having an in-screen infrared biosensor in accordance with a preferred embodiment of the present invention.

Fig. 1A is a schematic diagram showing a variation of the electronic device of fig. 1.

Fig. 2 shows a partial schematic view of the electronic device of fig. 1.

Fig. 2A is a schematic diagram showing a variation of the electronic device of fig. 2.

Fig. 3 is a schematic diagram illustrating an example of a combination structure of the backlight module, the display panel and the light-transmitting protection plate of fig. 1.

Fig. 4 is a partial schematic diagram showing an example of the actual configuration of fig. 1.

Fig. 5 and 6 are partial schematic views of two alternative configuration examples of fig. 4.

Fig. 7 to 9 are schematic diagrams showing three configurations of the infrared light source relative to the transparent protection plate.

Fig. 10 to 12 are schematic diagrams showing three variation examples of fig. 1.

Fig. 13 is a perspective view of the backlight module corresponding to fig. 10.

Fig. 14 shows a front view of the backlight module corresponding to fig. 13.

Fig. 15 and 16 are front views of two variations of the backlight module corresponding to fig. 14.

Fig. 17 is a perspective view of a variation of the backlight module corresponding to fig. 10.

Fig. 18 is a partial schematic view of the backlight module corresponding to fig. 10.

Fig. 19 shows a partial schematic view of the light guide plate corresponding to fig. 18.

Fig. 20 shows a partial schematic view of another example of the light guide plate corresponding to fig. 19.

Fig. 21 shows a schematic drawing of the dimensions of the various components of the light guide plate.

Fig. 22A to 22F show fingerprint images obtained using six different sizes of light guide plates.

FIG. 23 is a schematic diagram of an electronic device with an in-screen infrared biosensor in accordance with another embodiment of the present invention.

Fig. 24 shows a modification of the electronic apparatus of fig. 23.

FIG. 25 is a front view of a variation of the optical sensor and infrared light source of FIG. 23.

FIG. 26 is a top view of the optical sensor of FIG. 25.

F: biological body

FR: peak part

FT: free end

FV: trough part

H: height

IR 0: initial infrared ray

IR 1: infrared light

IR 2: reflected infrared light

P: pitch of

R: radius of

VL: visible light

10: backlight module

11: reflective layer

12: light guide plate

12A: substrate

12B: arc convex part

12C: v-shaped cutting part

12D: bottom surface

12E: the top surface

13: visible light source

14: visible light LED

15: diffusion brightening layer

16: diffusion layer

17: brightness enhancement film

18: driver

20: display panel

21: rear polarizer

22: rear alignment layer

23: liquid crystal layer

24: front electrode

25: color filter layer

26: front polarizer

30: light-transmitting protective plate

31: anti-reflection layer

32: optical transparent adhesive

40: optical sensor

41: lens module

42: sensing unit

50: infrared light source

51: light emitting unit

52: lens with specific curvature

53: optical film

55: circuit board

56: light guide plate

90: battery with a battery cell

100: electronic device

Detailed Description

The inventor found that Infrared (IR) can penetrate the ARC, so that the IR is applied to the finger, and the reflected IR is received by the CIS module through the cover glass, the display panel and the backlight module, thereby achieving fingerprint sensing. However, if the finger is touched with IR from the bottom of the backlight module, the IR will pass through the backlight module in the upward direction, and the IR will pass through the backlight module in the downward direction. In this way, the outgoing IR is blurred and the reflected IR is also blurred, blurring the image of the sensed fingerprint. There are many problems to be solved if the IR is emitted from the front to the finger.

Four design architectures are proposed to achieve IR emission to the finger. The first is related to side-lighting, where IR is emitted from one side of the cover glass, where an ARC may be placed under the cover glass to keep the IR intensity incident on the cover glass at a high intensity. In this lighting method, Total Internal Reflection (TIR) may be used. The second is related to changing the design of the backlight module, placing some IR LEDs in the LED array of the visible light (red, green, blue GB) at the side of the backlight module. The third is related to the use of a linear array of RGB LEDs and a linear array of another IR LED arranged in parallel. A fourth approach is to modify the design of the light guide module in such a way that IR illumination can be placed at all possible locations, including lateral illumination and bottom illumination.

FIG. 1 is a diagram of an electronic device 100 with an in-screen infrared biosensor in accordance with a preferred embodiment of the present invention. Fig. 2 shows a partial schematic diagram of the electronic device 100 of fig. 1. The electronic device 100 is, for example, a mobile phone, a tablet computer, a wearable device, an electronic device with a biometric sensing function, or the like. As shown in fig. 1 and fig. 2, the electronic device 100 at least includes a backlight module 10, a display panel 20, a transparent protection plate 30, an optical sensor 40 and an infrared light source 50. The electronic device 100 has a function of displaying information for interaction with a user, and may also have a touch function for allowing a user to input commands or data. For example, when the user uses the optical sensor 40 to sense the biometric feature, the user can perform login, biometric feature comparison, and the like, and if the biometric feature comparison passes, the central processing unit (not shown) of the electronic device 100 can unlock the device to allow the user to perform further operations or perform transactions, and the like.

The backlight module 10 provides the visible light VL to travel upward, and the backlight module 10 has a reflective layer 11 for blocking the visible light VL from traveling downward (away from the display panel 20). The Display panel 20 is disposed above the backlight module 10 and is used for displaying information according to the visible light VL, and the application of the Display panel to a mobile device such as a mobile phone may be a Display unit (Display Cell) or a Display unit with a touch function. The light-transmitting protective plate 30 is disposed above the display panel 20 to allow information to pass through, and may be Cover Glass (CG) used in mobile devices such as mobile phones. The optical sensor 40 is disposed below the backlight module 10. In one example, the optical sensor 40 is a lens type optical sensor, which uses a lens or a combination of lenses to achieve the image sensing function, and in another example, the optical sensor 40 is an ultra-thin optical sensor with a micro-lens collimator design.

The infrared light source 50 provides infrared light IR1 to a biological subject F located on or over the light transmissive protective plate 30. In the present embodiment, the infrared light source 50 is disposed above the reflective layer 11. The living body F, such as a finger, reflects the infrared light IR1 to generate a reflected infrared light IR2, and the reflected infrared light IR2 is received by the optical sensor 40 through the transparent protection plate 30, the display panel 20 and the backlight module 10, so that the optical sensor 40 obtains an image signal representing an image of the living body F. The image contains fingerprint image, blood vessel image, blood oxygen concentration image, etc. of the biological organ information on the skin surface layer or the skin lower layer. The above configuration structure can achieve the effect of the present invention, and achieve the function of the in-screen infrared biological sensing. Note that the "reflection" may be a phenomenon in which infrared light is reflected by the surface of the living body F, or a phenomenon in which infrared light enters the living body F and is emitted from the living body F.

In the present embodiment, the infrared light source 50 is disposed below the transparent protection plate 30 and on one side of the display panel 20. That is, the area of the light-transmissive protection plate 30 is larger than the area of the display panel 20, and the infrared light source 50 is disposed in the redundant space formed by the light-transmissive protection plate 30 and the display panel 20. The optical sensor 40 is disposed below the backlight module 10 and beside the battery 90 of the electronic device 100. Another embodiment of the optical sensor 40 (e.g., with an ultra-thin microlens collimator design) can be disposed between the battery 90 and the backlight module 10, as shown in fig. 1A.

As shown in fig. 2, the infrared light IR1 passes through an anti-reflection layer 31 of the light-transmissive protection plate 30, and the anti-reflection layer 31 prevents the infrared light IR1 from being reflected by the light-transmissive protection plate 30 and not reaching the living body F. As shown in fig. 2A, the infrared light source 50 is located below the backlight module 10, and provides a bottom lighting manner, which is also applicable to the above embodiments.

Fig. 3 is a schematic diagram illustrating an example of a combination structure of the backlight module 10, the display panel 20 and the light-transmissive protection plate 30 in fig. 1. As shown in fig. 3, the backlight module 10 and the Display panel 20 form a Liquid Crystal Display (LCD). In a non-limiting example, the backlight module 10 at least includes a reflective layer 11, a Light Guide Plate (LGP) 12, a visible Light source 13 and a diffusion brightness enhancing layer 15. The diffusing Brightness enhancing layer 15 includes a diffusing layer (DIFF) 16 and a Brightness Enhanced Film (BEF) 17. The reflective layer 11 is, for example, an Enhanced Specular Reflector (ESR) produced by 3M company. The display panel 20 includes a Rear Polarizer (real Polarizer)21, a Rear alignment layer 22, a liquid crystal layer 23, a front electrode 24, a color filter layer 25, and a front Polarizer (FrontPolarizer)26 stacked in this order from the bottom to the top, but the present invention is not limited thereto. In addition, the display panel 20 is adhered to the light-transmissive protection plate 30 by an Optically Clear Adhesive (OCA) 32. It should be noted that fig. 3 shows only one example, and the invention is not particularly limited thereto. In the case of visible light, the diffusion layer 16 and the brightness enhancement film 17 blur an image, the light guide plate 12 deteriorates image quality, and the reflection layer 11 reflects the visible light upward. However, the present inventors have found that for infrared light, the infrared light can penetrate the reflective layer 11 without being greatly affected by the diffusion layer 16, the brightness enhancement film 17 and the light guide plate 12. Therefore, the configuration of the embodiment of the present invention is suitable for the application of the LCD, but is not particularly limited thereto, and for example, a display provided with a reflective layer that reflects visible light is also an application of the embodiment of the present invention.

Fig. 4 is a partial schematic diagram showing an example of the actual configuration of fig. 1. As shown in fig. 4, a driver 18 of the electronic apparatus 100 controls operations of the backlight module 10 and the display panel 20, so that the electronic apparatus 100 can display information to a user. As shown in fig. 4, the infrared light IR1 penetrates through the transparent protection plate 30 and irradiates on a peak FR of the living body F directly contacting the transparent protection plate 30 to generate a reflected infrared light IR2, and the reflected infrared light IR2 is coupled into the transparent protection plate 30, so that a portion of the image corresponding to the peak FR appears bright. On the other hand, a valley FV of the living body F cannot reflect the infrared light IR1 passing through the light-transmissive protection plate 30, so that a portion of the image corresponding to the valley FV appears dark. In one example, a distance between the infrared light source 50 and the living body F is between 10mm and 30mm or between 15mm and 20mm, or a distance between the sensing region of the living body F and the infrared light source 50 is between 10mm and 30mm or between 15mm and 20 mm. In the example shown in fig. 4, a relatively uniform light field can be obtained, enhancing image sensing results.

Fig. 5 and 6 are partial schematic views of two alternative configuration examples of fig. 4. As shown in fig. 5, the infrared light IR1 penetrates through the transparent protection plate 30 and irradiates on a free end FT of the living body F, and the free end FT couples into the living body F to generate reflected infrared light IR2, or infrared light IR1 scatters in the living body F to generate reflected infrared light IR 2. In this case, the peak portions FR of the living body F directly contacting the light-transmissive protective plate 30 couple the reflected infrared light IR2 into the light-transmissive protective plate 30, so that a part of the image corresponding to the peak portions FR appears bright, and the valley portions FV cannot couple the reflected infrared light IR2 into the living body F. In this example, the illumination light received by the living body F is relatively uniform, and the change is relatively small compared to the mode of fig. 6 described later, and there is also a problem that the residue on the light-transmitting protective plate 30 does not affect the image sensing. The distance between the infrared light source 50 and the living body F is between 15mm and 20mm, or the distance between the sensing region of the living body F and the infrared light source 50 is between 15mm and 20 mm. As shown in fig. 6, the infrared light IR1 is totally reflected inside the transparent protection plate 30, the peak portions FR of the living body F directly contacting the transparent protection plate 30 couple the infrared light IR1 into the living body F, so that a portion of the image corresponding to the peak portions FR appears dark, and the valley portions FV cannot couple the infrared light IR1 into the living body F, so that the corresponding portion sensed by the optical sensor 40 appears bright. The advantage of using total reflection is that the distance between the infrared light source 50 and the living body F can be relatively long, and the light field is relatively uniform, because the degree of attenuation of the infrared light is not high to make the total reflection efficiency reach a certain level.

Fig. 7 to 9 are schematic diagrams showing three configurations of the infrared light source relative to the transparent protection plate. These three configurations can be applied to the structures of fig. 4 to 6, respectively. As shown in fig. 7, the light field can be changed by rotating the configuration angle of the light emitting units of the infrared light source 50, so that the circuit board 55 mounted with the light emitting units is in a tilted non-horizontal state, which can provide a better light field for the living body, and the frame of the current mobile device is about 1mm to allow the infrared light source 50 to rotate, but can also be enlarged to provide a proper rotation space. As shown in fig. 8, the infrared light source 50 includes: a light emitting unit 51 emitting infrared light IR 1; and a lens 52 with specific curvature covering the light-emitting unit 51 for changing the light divergence angle and the light field of the infrared light IR 1. The Light Emitting unit 51 includes a Light-Emitting Diode (LED) or a Laser Diode (LD) including a Vertical-Cavity Surface-Emitting Laser (Vertical-Cavity Surface-Emitting Laser). In one example, the LD emits light at a wavelength of 940 nanometers (nm). In fig. 8, the light divergence angle and the light field can be changed by using a special area ratio lens or structure by changing the package of the LED or LD, and in the current technology, the package of 0402 LED can be used.

As shown in fig. 9, the infrared light source 50 includes: a light emitting unit 51 emitting infrared light IR 1; and an optical film 53 disposed on the light-emitting unit 51, wherein the optical film 53 is adhered to the light-transmitting protection plate 30 and covers the light-emitting unit 51 to change the light divergence angle and the light field of the infrared IR1, the light-emitting unit 51 includes a light-emitting diode or a laser diode, and the optical film 53 includes a grating (grating), a Fresnel lens or element, or a diffraction element. When designing, the light-emitting angle can be controlled by selecting the diffraction term or level of the grating. The Diffractive element is, for example, a Diffractive Optical Element (DOE). In the optical film, it is preferable to use nearly parallel light output, so that it is possible to match with an LED or LD, and to make simple collimation effect by using a collimator or a collimation structure on the package, and then to use these elements to change and control the light angle and the light field, so that the design is easier. Alternatively, the optical film may integrate the functions of at least two of the collimating, grating, Fresnel lens, and diffractive elements to produce the desired light field.

Therefore, in fig. 9, the optical film can be attached to the side surface or the bottom surface of the light-transmitting protection plate 30, and then the LED or the LD is attached to the optical film to change the light divergence angle and the light field, so that the mechanism is easy to assemble, the frame does not need to be enlarged, the thickness is increased slightly, and the entire LCD is not affected by the increased thickness, so that the cost can be reduced, for example, the optical film can be manufactured by nanoimprint. In addition, since the LED and the optical film are bonded, near-field optical considerations are required in the design. By the arrangement, the light field can be changed to meet the function of sensing the biological characteristics.

Fig. 10 to 12 are schematic diagrams showing three variation examples of fig. 1. Fig. 13 is a perspective view of the backlight module corresponding to fig. 10. Fig. 14 shows a front view of the backlight module corresponding to fig. 13. As shown in fig. 10, 13 and 14, the infrared light source 50 and the visible light source 13 of the backlight module 10 are disposed on the same side of the backlight module 10. In detail, the light emitting units 51 of the infrared light source 50 and the visible light emitting diodes 14 of the visible light source 13 of the backlight module 10 are disposed on the same side of the light guide plate 12 of the backlight module 10. Viewed from another angle, the light emitting units 51 and the visible light emitting diodes 14 are disposed alternately on the same side of the light guide plate 12 and are aligned in a straight line. It should be noted that although fig. 14 illustrates 2 ir leds as an example, in another example, 4 ir leds are inserted between the visible leds 14 to obtain an optical field for image sensing.

Fig. 15 and 16 are front views of two variations of the backlight module corresponding to fig. 14. As shown in fig. 11 and 15, the light emitting units 51 and the visible light emitting diodes 14 are disposed on the same side of the light guide plate 12 and are arranged in two lines. As shown in fig. 11 and 16, the light emitting units 51 and the visible light emitting diodes 14 are disposed on the same side of the light guide plate 12 and are arranged in two lines, and the distribution area of the light emitting units 51 is smaller than that of the visible light emitting diodes 14.

As shown in fig. 12, the plurality of light emitting units 51 of the infrared light source 50 and the plurality of visible light emitting diodes 14 of the visible light source 13 of the backlight module 10 are disposed on opposite sides of the light guide plate 12 of the backlight module 10.

Fig. 17 is a perspective view of a variation of the backlight module corresponding to fig. 10. As shown in fig. 17, the plurality of light emitting units 51 of the infrared light source 50 and the plurality of visible light emitting diodes 14 of the visible light source 13 of the backlight module 10 are disposed at adjacent sides of the light guide plate 12 of the backlight module 10.

Fig. 18 is a partial schematic view of the backlight module corresponding to fig. 10. Fig. 19 shows a partial schematic view of the light guide plate corresponding to fig. 18. As shown in fig. 18 and 19, the backlight module 10 is applied to the display panel 20 or used with the display panel 20, so as to provide light required for information display and biological sensing. The light guide plate 12 of the backlight module 10 cooperates with the infrared light source 50 to generate infrared IR1 (the light source 50 is not a necessary element here, as it can also be disposed at the side as shown in fig. 4 to 6, that is, infrared light is reflected from a fingerprint and then transmitted through the backlight module to be detected by the optical sensor 40), and the visible light source 13 is disposed at one side of the light guide plate 12 and emits light into the light guide plate 12 to generate visible light VL. The light guide plate 12 at least includes a base 12A, a plurality of arcuate projections (Dot)12B and a plurality of V-cuts (V-cut) 12C. The arc-shaped protrusion 12B is disposed on a bottom surface 12D of the substrate 12A for breaking the total reflection of the light in the substrate 12A to generate the visible light VL. The V-shaped cut 12C is disposed on a top surface 12E of the substrate 12A for breaking the total reflection of the light in the substrate 12A to generate the visible light VL. That is, in the case of having no convex part 12B and no V-shaped cut part 12C, the light of the visible light source 13 can only be totally reflected in the substrate 12A, and the light is guided out by the convex part 12B and/or the V-shaped cut part 12C to generate the visible light VL. Since the convex 12B and the V-shaped cut 12C also affect the infrared light, the convex 12B and the V-shaped cut 12C need to be designed better to obtain an acceptable fingerprint image without affecting the visible light VL.

Fig. 20 shows a partial schematic view of another example of the light guide plate corresponding to fig. 19. As shown in fig. 20, the V-cut 12C may not be provided.

Fig. 21 shows a schematic drawing of the dimensions of the various components of the light guide plate. As shown in fig. 21, the arcuate projections 12B have a radius R and a height H. The pitch (pitch) of the arcuate projections 12B is equal to the pitch P. Fig. 22A to 22F show fingerprint images obtained using six different sizes of light guide plates. In the present disclosure, six different design parameters (as listed in table 1) are used to obtain six fingerprint images (fig. 22A to 22F), and Modulation Transfer Function (MTF) values (representing the degree of image blur) are also listed in table 1.

TABLE 1

Examples of the present invention	R(μm)	H(μm)	P(μm)	P/H	MTF(％)
						1	31.64	0.52	60.08	115.5	70.30
2	31.31	1.39	59.8	43.02	43.7
						3	37.87	2.6	119.96	46.13	68.5
4	40.34	2	80.33	40.16	53.8
						5	79.85	1.17	35.58	30.4	6.7
6	100.75	0.5	19.92	39.94	56.1

In the above six examples, the light guide plates 12 of all the examples have little difference in the display function, so that by comparing the MTF values of the fingerprint images, which parameters are better parameters can be obtained. As can be seen from Table 1 and FIGS. 22A to 22F, the MTF values have a correlation with P/H, and from the first and second examples, the radius R is the same, but the larger the P/H value, the higher the MTF value. In the second example, the fourth example and the sixth example, the P/H is almost the same, but the larger the R value is, the higher the MTF value is, although the P/H value of the sixth example is slightly lower than that of the second and fourth examples, but the contribution of the R value can be made higher the MTF value of the sixth example. However, there is no absolute linear relationship, and the MTF value drops sharply when P/H is lower than a certain value, as can be seen from the fifth example. As shown in fig. 22C corresponding to the third example, although the MTF value is high, moire fringes (moire pattern) are generated on the image, and according to other experimental results, P is preferably not more than 100 micrometers, and more preferably not more than 80 micrometers.

Therefore, according to the above and other experimental results, the design specifications are unified as follows with respect to the application of the fingerprint aspect. The pitch P of the distribution of the arcuate projections 12B is less than or equal to 150, 100 or 80 μm to avoid moire. The radius of each convex segment 12B is between 10 and 300 micrometers (between 10 and 150 micrometers, or between 30 and 120 micrometers, preferably between 20 and 110 micrometers), and the ratio of the pitch P to the height H of each convex segment 12B is between 30 and 300 (between 20 and 150, between 30 and 120 micrometers, or preferably between 35 and 45), and P/H is equal to 40 in one design example. When P/H is increased, improved fingerprint image quality can be obtained. Therefore, the above design specifications can suppress moire and increase the MTF value without affecting the display function. Of course, the present disclosure is not only applicable to side polishing and light guide plate polishing, but also applicable to bottom polishing.

By the embodiment, the optical sensing module arranged below the LCD can obtain a good biological characteristic image by utilizing infrared light without influencing the display function of the LCD, the reflecting layer of the LCD has different characteristics for infrared light and visible light, so that the reflecting layer which can not be penetrated by the visible light can be penetrated by the infrared light, the infrared light reflected by fingers can easily penetrate the reflecting layer to reach the optical sensor arranged below the reflecting layer, the biological characteristic sensing function is achieved, and an optical biological sensing scheme is provided for an electronic device provided with the LCD.

The above design, in addition to being suitable for LCD displays, can be suitably modified to be suitable for other displays, such as OLED displays or displays that may be developed in the future, such as uuleds, etc. FIG. 23 is a schematic diagram of an electronic device with an in-screen infrared biosensor in accordance with another embodiment of the present invention. As shown in fig. 23, the present embodiment provides an electronic device 100, which at least includes a display panel 20, a light-transmissive protective plate 30, an optical sensor 40, and an infrared light source 50. The display panel 20 provides the visible light VL to travel upward, and displays information according to the visible light VL. The display panel 20 includes, but is not limited to, an Organic Light Emitting Diode (OLED) display panel. The light-transmissive protection plate 30 is disposed above the display panel 20 to allow information to pass therethrough. The optical sensor 40 is disposed below the display panel 20. The infrared light source 50 provides infrared light IR1 to a biological subject F located on or over the light transmissive protective plate 30. The Infrared IR1 is, for example, Near Infrared (NIR) having a wavelength of about 0.75 to 1.4 microns. The living body F reflects the infrared light IR1 to generate reflected infrared light IR 2. The reflected infrared IR2 is received by the optical sensor 40 through the transparent protection plate 30 and the display panel 20, so that the optical sensor 40 obtains an image signal representing an image of the living body F. In the present example, the infrared light source 50 is located at one side of the display panel 20. By the above arrangement, the function of in-screen infrared biosensing can also be achieved.

Fig. 24 shows a modification of the electronic apparatus of fig. 23. As shown in fig. 24, a difference from fig. 23 is that the infrared light source 50 is located below the display panel 20. The infrared light source 50 has one or more light emitting units 51, such as light emitting diodes, and the light emitting units 51 can be disposed beside or around the optical sensor 40 and provide infrared IR1 to penetrate the display panel 20 and the transparent protection plate 30 to reach the living body F, so as to achieve the function of in-screen infrared biosensing.

FIG. 25 is a front view of a variation of the optical sensor and infrared light source of FIG. 23. FIG. 26 is a top view of the optical sensor of FIG. 25. As shown in fig. 25 and 26, the infrared light source 50 includes one or more light emitting units 51 and a light guide plate 56. The light emitting unit 51 provides an initial infrared ray IR 0. The light guide plate 56 is disposed around the optical sensor 40 and guides the initial infrared light IR0 to generate infrared light IR 1. In the present example, the optical sensor 40 includes a sensing unit 42 and a lens module 41, and the optical sensor can also be an ultra-thin optical sensor with a micro-lens collimator design. The reflected infrared light IR2 passes through the lens module 41 and is focused on the sensing unit 42 to obtain a sensed image. The lens module 41 may be a single lens, a stack of multiple lenses, or a two-dimensional array of multiple lenses. The light guide plate 56 may have a ring structure (such as a circular ring or a polygonal ring structure) disposed around the lens module 41, so that the light of the light emitting unit 51 can be processed into uniform and upward-going infrared IR1 by the light guide plate 56, thereby providing uniform infrared light to improve the sensing quality. The light emitting unit 51 may be disposed at a side or lower side of the light guide plate 56.

Therefore, embodiments of the present invention can provide an optical bio-sensing scheme for an electronic device equipped with an LCD or OLED display, including an electronic device having an in-screen infrared bio-sensor and a backlight module applied to a display panel.

The detailed description of the preferred embodiments is provided only for the convenience of illustrating the technical contents of the present invention, and the present invention is not limited to the above embodiments in a narrow sense, and various modifications can be made without departing from the spirit of the present invention and the scope of the claims.

Claims

1. An electronic device having an in-screen infrared biosensor, comprising:

the backlight module provides visible light to move upwards, and is provided with a reflecting layer for blocking the visible light from moving downwards;

a display panel arranged above the backlight module and used for displaying information according to the visible light;

a transparent protective plate arranged above the display panel to allow the information to penetrate through;

an optical sensor disposed below the backlight module; and

an infrared light source, providing infrared light to a living body on or above the transparent protection plate, the living body reflecting the infrared light to generate reflected infrared light, the reflected infrared light passing through the transparent protection plate, the display panel and the backlight module and being received by the optical sensor, so that the optical sensor obtains an image signal representing an image of the living body.

2. The electronic device as claimed in claim 1, wherein the infrared light source is disposed under the light transmissive protective plate and at a side of the display panel.

3. The electronic device as claimed in claim 2, wherein the infrared light passes through an anti-reflection layer of the transparent protective plate, the anti-reflection layer preventing the infrared light from being reflected and failing to reach the organism.

4. The electronic device of claim 2, wherein the infrared light is totally reflected within the light-transmissive protective plate.

5. The electronic device as claimed in claim 2, wherein the infrared light penetrates the transparent protective plate to irradiate a free end of the living body, and the free end is coupled into the living body to generate the reflected infrared light.

6. The electronic device of claim 5, wherein a peak of the biological object directly contacting the transparent protective plate couples the reflected infrared light into the transparent protective plate, so that a portion of the image corresponding to the peak appears bright.

7. The electronic device of claim 5, wherein a distance between the infrared light source and the biological object is between 10mm and 30 mm.

8. The electronic device of claim 2, wherein the infrared light penetrates the transparent protective plate to impinge on a peak of the biological body directly contacting the transparent protective plate to generate the reflected infrared light.

9. The electronic device of claim 8, wherein the reflected infrared light is coupled into the transparent protective plate to make a portion of the image corresponding to the peak appear bright.

10. The electronic device of claim 9, wherein a distance between the infrared light source and the biological object is between 10mm and 30 mm.

11. The electronic device of claim 2, wherein the infrared light source comprises: a light emitting unit emitting the infrared light; and a lens with specific curvature covering the light emitting unit to change the light divergence angle and the light field of the infrared light, wherein the light emitting unit comprises a light emitting diode or a laser diode, and the laser diode comprises a vertical cavity surface emitting laser.

12. The electronic device of claim 2, wherein the infrared light source comprises: a light emitting unit emitting the infrared light; and an optical film disposed on the light-emitting unit, wherein the optical film is adhered to the light-transmitting protective plate and covers the light-emitting unit to change the light divergence angle and the light field of the infrared light, and the light-emitting unit includes a light-emitting diode or a laser diode including a vertical cavity surface emitting laser.

13. The electronic device of claim 12, wherein the optical film comprises a grating, a fresnel lens or element, or a diffractive element.

14. The electronic device of claim 1, wherein the infrared light source and a visible light source of the backlight module are disposed on a same side of the backlight module.

15. The electronic device of claim 1, wherein the light-emitting units of the infrared light source and the visible light-emitting diodes of a visible light source of the backlight module are disposed on a same side of a light guide plate of the backlight module.

16. The electronic device according to claim 15, wherein the light-emitting units and the visible light-emitting diodes are alternately arranged on the same side of the light guide plate and are aligned in a straight line.

17. The electronic device according to claim 15, wherein the light emitting units and the visible light emitting diodes are disposed on the same side of the light guide plate and are arranged in two lines.

18. The electronic device according to claim 15, wherein the light-emitting units and the visible light-emitting diodes are disposed on the same side of the light guide plate and are arranged in two lines, and the distribution area of the light-emitting units is smaller than that of the visible light-emitting diodes.

19. The electronic device of claim 1, wherein the light-emitting units of the infrared light source and the visible light-emitting diodes of a visible light source of the backlight module are disposed on adjacent sides of a light guide plate of the backlight module.

20. The electronic device of claim 1, wherein the light-emitting units of the infrared light source and the visible light-emitting diodes of a visible light source of the backlight module are disposed on opposite sides of a light guide plate of the backlight module.

21. The electronic device of claim 1, wherein a peak of the biological object directly contacting the light-transmissive protective plate couples the infrared light into the biological object, so that a portion of the image corresponding to the peak appears dark.

22. The electronic device of claim 1, wherein the backlight module further comprises:

a light guide plate, which cooperates with the infrared light source to generate the infrared light; and

the visible light source is arranged on one side of the light guide plate and emits light rays which enter the light guide plate to travel so as to generate the visible light.

23. The electronic device of claim 22, wherein the light guide plate further comprises:

a substrate; and

and the plurality of V-shaped cutting parts are arranged on one top surface of the substrate and are used for destroying the total reflection of the light in the substrate to generate the visible light.

24. The electronic device of claim 22, wherein the light guide plate comprises:

a substrate; and

the arc-shaped convex parts are arranged on one bottom surface of the substrate and used for destroying the total reflection of the light in the substrate to generate the visible light.

25. The electronic device of claim 24, wherein the light guide plate further comprises:

26. The electronic device of claim 24, wherein the pitch of the plurality of arcuate projections is less than or equal to 150 microns.

27. The electronic device of claim 24, wherein a radius of each of the arcuate projections is between 10 and 150 μm.

28. The electronic device according to claim 24, wherein a ratio of a pitch of each of the convex segments to a height of each of the convex segments is between 20 and 150.

29. The electronic device according to claim 24, wherein a pitch of the plurality of convex segments is less than or equal to 150 μm, a radius of each convex segment is between 10 and 150 μm, and a ratio of the pitch to a height of each convex segment is between 20 and 150.

30. The electronic device of claim 24, wherein the pitch of the distribution of the plurality of arcuate projections is less than or equal to 80 microns.

31. The electronic device of claim 24, wherein a radius of each of the arcuate projections is between 20 and 110 μm.

32. The electronic device according to claim 24, wherein a ratio of a pitch of each of the convex segments to a height of each of the convex segments is between 30 and 120.

33. The electronic device according to claim 24, wherein a pitch of the plurality of convex segments is less than or equal to 80 μm, a radius of each convex segment is between 20 and 110 μm, and a ratio of the pitch to a height of each convex segment is between 30 and 120.

34. An electronic device having an in-screen infrared biosensor, comprising:

a display panel, which provides visible light to move upwards and displays information according to the visible light;

an optical sensor disposed below the display panel; and

an infrared light source, providing infrared light to a living body on or above the transparent protection plate, the living body reflecting the infrared light to generate reflected infrared light, the reflected infrared light passing through the transparent protection plate and the display panel to be received by the optical sensor, so that the optical sensor obtains an image signal representing an image of the living body.

35. The electronic device of claim 34, wherein the infrared light source is located on one side of the display panel.

36. The electronic device of claim 34, wherein the infrared light source is located below the display panel.

37. The electronic device of claim 36, wherein the infrared light source comprises one or more light emitting units located near the optical sensor and providing the infrared light.

38. The electronic device of claim 36, wherein the infrared light source comprises:

one or more light emitting units providing an initial infrared ray; and

and the light guide plate is positioned around the optical sensor and guides the initial infrared light to generate the infrared light.

39. The electronic device of claim 34, wherein the display panel is an organic light emitting diode display panel.