TWM602668U - Optical biometrics sensor with anti-cross-talk structure - Google Patents

Abstract

An optical biometrics sensor includes: a sensing substrate having adjacent first and second light sensing cells; an optical module layer including: a light-obstructing layer being disposed on the sensing substrate and including adjacent first and second apertures; and a light-permeable support layer disposed on the light-obstructing layer and in the first and second apertures; and micro-lenses disposed on the optical module layer. The micro-lenses include adjacent first and second micro-lenses. The first micro-lens focuses normal light from an object onto the first light sensing cell through the optical module layer and the first aperture. The light-obstructing layer has a predetermined thickness, so that oblique light, coming from the object, travel to the light-obstructing layer through the second micro-lens and the optical module layer without entering the first aperture and the first light sensing cell.

Description

Optical biological characteristic sensor with anti-stray light interference structure

The present invention relates to an optical biometric sensor, and particularly relates to an optical biometric sensor with an anti-stray light interference structure, which uses a thickened light shielding layer to achieve the effect of preventing stray light interference.

Today's mobile electronic devices (such as mobile phones, tablet computers, laptops, etc.) are usually equipped with user biometric systems, including different technologies such as fingerprints, face shapes, iris, etc., to protect personal data security, such as mobile phones Or smart watches and other portable devices also have the function of mobile payment, which has become a standard function for user biometrics, and the development of mobile phones and other portable devices is toward full screen (or ultra-narrow bezel) The trend of the traditional capacitive fingerprint button can no longer be used, and the evolution of a new miniaturized optical imaging device (very similar to the traditional camera module, with complementary metal-oxide semiconductor (CMOS) Image Sensor (CIS for short) sensing components and optical lens modules). The miniaturized optical imaging device is placed at the bottom of the screen (can be called under the screen), through the screen part of the light (especially organic light emitting diode (Organic Light Emitting Diode, OLED) screen), can capture the press on the top of the screen The image of the object, especially the fingerprint image, can be called Fingerprint On Display (FOD).

Figures 1 to 3 respectively show schematic diagrams of three conventional optical fingerprint sensors. As shown in FIG. 1, the traditional under-screen TFT optical fingerprint sensor 300 has a sensing substrate 310 and an optical-mechanical structure 320 to achieve the purpose of capturing images. The optical-mechanical structure 320 is a laminated fiber board (Fiber Optical Plate (FOP) is used as a collimator. FOP has the problems of high price and low productivity, which is not conducive to the development of optical fingerprint sensors.

As shown in FIG. 2, another conventional under-screen TFT optical fingerprint sensor 400 has a sensing substrate 410 and an optical-mechanical structure 420 to achieve the purpose of capturing images. The optical-mechanical structure 420 is a lens film laminated type The collimation structure of the microlens film is produced by a roll to roll (Roll to Roll) process. Although it has the advantages of low price and high productivity, it still has problems such as poor performance.

As shown in FIG. 3, the optomechanical structure 420 has a light shielding layer 425, a transparent dielectric layer 422 and a plurality of microlenses 424. Because the traditional design mainly considers that as long as the light shielding layer 425 can achieve the light transmission effect of the forward light L1 as the signal light in the light hole 423, only the aperture of the light hole 423 is designed. However, under certain conditions, the light shielding layer 425 that is not properly designed may cause cross-talk of the oblique light L2 to the signal light received by the light sensor element 411, and cause the signal light The signal-to-noise ratio becomes worse, making the quality of the fingerprint image poor.

Therefore, one object of the present invention is to provide an optical biometric sensor with an anti-stray light interference structure, which uses a thickened shading layer to achieve the effect of preventing stray light interference. The thickness of the shading layer depends on the optical biometric sensor. The layout parameters of other components of the device.

To achieve the above objective, the present invention provides an optical biometric sensor at least comprising: a sensing substrate with a first light sensing element and a second light sensing element adjacent to each other; and a light module layer, at least Including: a light shielding layer located on the sensing substrate and including adjacent A first light hole and a second light hole; and a light-transmitting support layer located on the light shielding layer and in the first light hole and the second light hole; and a plurality of micro lenses located on the light module layer. These micro lenses include a first micro lens and a second micro lens adjacent to each other. The first micro lens focuses a forward light from an object through the light module layer and the first light hole to reach the first light sensor. For the sensing element, the light shielding layer has a predetermined thickness, so that an oblique light from the object passes through the second microlens and the light module layer and hits the light shielding layer, but does not enter the first light hole and the first light sensing element in. The predetermined thickness of the light shielding layer is t, the aperture of the first light hole is d, the thickness of the light module layer is H, and the center distance between the first microlens and the second microlens is P, where (t/d)>0.3 *(H/P), t<H, and d<P.

With the above-mentioned optical biometric sensor, a thickened light shielding layer can be used to prevent stray light interference. The thickness of the light shielding layer depends on the layout parameters of other components of the optical biometric sensor. The light shielding layer is an anti-stray light interference structure, which resists the interference of stray light transmitted by adjacent microlenses, so that the signal-to-noise ratio of the image signal of the biological characteristic obtained by the optical biological characteristic sensor is higher, and the quality obtained is better. Excellent fingerprint image.

In order to make the above-mentioned content of the present invention more obvious and understandable, the following is a detailed description of preferred embodiments in conjunction with the accompanying drawings.

d, d2, d2: aperture

F: Object

H: thickness

P: Center spacing

t: thickness

L1: Forward light

L2: Oblique light

10: Sensing substrate

11: The first light sensor element

12: The second light sensor element

13: Glass substrate

14: Semiconductor substrate

20: Optical module layer

21: The first light hole

22: second light hole

23: The first shading film

23A: The first sub-aperture

23B: second sub-aperture

24: second shading film

24A: third sub-aperture

24B: Fourth sub-aperture

25: shading layer

26: Transparent support layer

40: Micro lens

41: The first micro lens

42: second micro lens

50: display

51, 52: transparent substrate

100', 100: optical biometric sensor

300: Optical fingerprint sensor

310: Sensing substrate

320: Optical machine structure

400: Optical fingerprint sensor

410: sensing substrate

411: Light Sensor

420: Optical machine structure

422: transparent dielectric layer

423: light hole

424: Micro lens

425: shading layer

[Figure 1] to [Figure 3] respectively show schematic diagrams of three conventional optical fingerprint sensors.

[Figure 4] shows a schematic diagram of the optical biometric sensor of the preferred embodiment of the present invention.

[Figure 5] shows a schematic diagram of a variation of [Figure 4].

[Figure 6] shows a schematic diagram of the applications of [Figure 4] and [Figure 5].

[Figure 7] shows a schematic diagram of another application of [Figure 4] and [Figure 5].

[Figure 8] shows a schematic diagram of another variation of [Figure 4].

FIG. 4 shows a schematic diagram of the optical biometric sensor 100 according to a preferred embodiment of the present invention. As shown in FIG. 4, the optical biometric sensor 100 is illustrated by taking a fingerprint sensor as an example, but the present invention is not limited to this. The optical biometric sensor 100 can also sense blood vessel images of a finger. , Biological features such as blood oxygen concentration images, or biological features such as face shape and iris. The optical biometric sensor 100 at least includes a sensing substrate 10, an optical module layer 20 and a plurality of micro lenses 40.

The sensing substrate 10 has a plurality of light sensing elements arranged in an array, wherein two adjacent light sensing elements are defined as a first light sensing element 11 and a second light sensing element 12.

The light module layer 20 at least includes a light shielding layer 25 and a transparent supporting layer 26. The light shielding layer 25 is located on the sensing substrate 10 and includes a plurality of light holes, wherein two adjacent light holes are defined as a first light hole 21 and a second light hole 22. The transparent support layer 26 is located on the light shielding layer 25 and in the first light hole 21 and the second light hole 22.

A plurality of micro lenses 40 are arranged in an array and are located on the light module layer 20. These microlenses 40 include a first microlens 41 and a second microlens 42 adjacent to each other. The first microlens 41 focuses a forward light L1 from an object F through the optical module layer 20 and the first light. The hole 21 reaches the first light sensing element 11. The light shielding layer 25 has a predetermined thickness, which has a corresponding lifting height, and depends on the physical characteristic parameters of the sensing substrate 10, the optical module layer 20, and the microlens 40, so that a diagonal light from the object F L2 strikes the light-shielding layer 25 through the second microlens 42 and the light module layer 20, but does not enter the first light hole 21 and the first light sensing element 11.

It should be noted that the forward light L1 may include light with a divergence angle ranging from the first light sensing element 11 to the first microlens 41, such as ±3 degrees to ±20 degrees or ±30 degrees, and the oblique light L2 includes Light rays other than forward light L1. With the structure of the light shielding layer of the optical biometric sensor, it is easy to increase the thickness of the light shielding layer to avoid stray light drying. Disturb.

Although in FIG. 4, the light-transmitting support layer 26 includes a single-layer transparent dielectric layer, in other examples, the light-transmitting support layer 26 may also include a combination of multiple transparent layers, such as an infrared filter layer, a grating layer, and a transparent layer. A combination of at least two or three of the dielectric layers. On the other hand, other insulating layers or insulating layer groups may be contained between the second photo sensor element 12 and the light-shielding layer 25, and the insulating layer groups may include a metal circuit layer and an intermetal dielectric layer. In this example, the light-shielding layer 25 has a solid structure as the light-shielding part, that is, the light-shielding layer 25 has a solid structure cross-section along a predetermined thickness direction (up and down direction of the drawing).

In FIG. 4, the predetermined thickness is t, the aperture of the first light hole 21 is d, the thickness of the optical module layer 20 is H, and the center distance between the first microlens 41 and the second microlens 42 is P, where ( The value of t/d) is greater than 0.3*(H/P), t<H, and d<P. (t/d) is equivalent to the aspect ratio of the first light hole 21. The applicant found that it depends on the ratio of the thickness (H) and the center distance (P) (at least 0.3). In the case that the process can be implemented, ( The value of t/d) is the larger the better. In some examples, the value of (t/d) is between 2*(H/P) and 0.3*(H/P), and between 1.8*(H/P) and 0.4*(H/P) Between 1.6*(H/P) to 0.5*(H/P), between 1.4*(H/P) to 0.6*(H/P), between 1.3*(H/P) ) To 0.7*(H/P), between 1.2*(H/P) to >0.8*(H/P) or between 1.1*(H/P) to 0.9*(H/P) between. In one example, (t/d) is approximately equal to (H/P).

In this example, the sensing substrate 10 includes at least one glass substrate 13, and the first light sensing element 11 and the second light sensing element 12 are formed on the glass substrate 13. Therefore, the optical biometric sensor 100 is a Thin-Film Transistor (TFT) optical biometric sensor.

Fig. 5 shows a schematic diagram of a modification of Fig. 4. As shown in FIG. 5, this example is similar to FIG. 4, except that the light shielding layer 25 is a hollow light shielding layer. Light-shielding layer 25 It has a cross section of a hollow structure along the direction of the predetermined thickness. The light shielding layer 25 at least includes a first light shielding film 23 and a second light shielding film 24. The first shading film 23 is located on the sensing substrate 10 and has a first sub-aperture 23A and a second sub-aperture 23B adjacent to each other. The second light-shielding film 24 is located above the first light-shielding film 23 and has a third sub-aperture 24A and a fourth sub-aperture 24B adjacent to each other. The first light hole 21 includes a first sub-aperture 23A and a third sub-aperture 24A, the second light hole 22 includes a second sub-aperture 23B and a fourth sub-aperture 24B, a first light-shielding film 23 and a second light-shielding film The farthest distance of 24 is equal to the predetermined thickness. If the predetermined thickness is t, the aperture of the first sub-aperture 23A is d1, and the aperture of the third sub-aperture 24A is d2, the aperture d of the first aperture 21 is defined as the average value of d1 and d2, t/[( d1+d2)/2]>0.3*(H/P), t<H, d1<P and d2<P. In the case that the process is feasible, the larger the value of t/[(d1+d2)/2], the better. In some examples, the value of t/[(d1+d2)/2] is between 2*(H/P) and 0.3*(H/P), and between 1.8*(H/P) and 0.4* (H/P), between 1.6*(H/P) and 0.5*(H/P), between 1.4*(H/P) and 0.6*(H/P), between 1.3*(H/P) to 0.7*(H/P), between 1.2*(H/P) to >0.8*(H/P) or between 1.1*(H/P) to 0.9 *(H/P). In one example, t/[(d1+d2)/2] is approximately equal to (H/P). In this example, although d1<d2, in other cases, it can be d1=d2 or d1>d2.

Fig. 6 shows a schematic diagram of the application scenarios of Figs. 4 and 5. As shown in FIG. 6, the optical biometric sensor 100' which is similar to the optical biometric sensor 100 and is interspersed and integrated with display pixels (not shown) can be applied to an organic light emitting diode (Organic Light Emitting Diode, OLED). ) A display or a liquid crystal display (Liquid Crystal Display, LCD) or any other display that is applied to a TFT process to make a TFT sensor is an in-cell sensor. Therefore, the glass substrate 13 is one of the two opposing light-transmitting substrates 51, 52 of the display 50 (in Figure 6 here, it refers to the light-transmitting substrate 51 below. It can also be said that the glass substrate 13 is a part of the light-transmitting substrate 51 ). The material between the two transparent substrates 51 and 52 The layer may be a material layer of OLED or LCD. Although FIG. 6 uses a partial optical biometric sensor 100' as an example for illustration, the content of the disclosure is not limited thereto. The optical biometric sensor 100' can also be extended to cover the entire range of the entire display 50 to become a full-screen optical biometric sensor.

FIG. 7 shows a schematic diagram of another application situation of FIG. 4 and FIG. 5. As shown in FIG. 7, the optical biometric sensor 100 can be arranged under an OLED, LCD or other display 50 that is applied to the TFT process to make a TFT sensor, and is an independent sensor.

Fig. 8 shows a schematic diagram of another modification of Fig. 4. As shown in Figure 8, this example is similar to Figure 4, the difference is that the sensing substrate 10 includes at least one semiconductor substrate 14. The first photo sensor element 11 and the second photo sensor element 12 are formed on the semiconductor substrate 14, the semiconductor substrate For example, a silicon substrate. That is, the optical biometric sensor 100 is a complementary metal-oxide semiconductor (Complementary metal-oxide semiconductor, CMOS) image sensor.

With the above-mentioned embodiments, a thickened light shielding layer can be used to achieve the effect of preventing stray light interference. The thickness of the light shielding layer depends on the layout parameters of other components of the optical biometric sensor. The light shielding layer is an anti-stray light interference structure, which resists the interference of stray light transmitted by adjacent microlenses, so that the signal-to-noise ratio of the image signal of the biological characteristic obtained by the optical biological characteristic sensor is higher, and the quality obtained is better. Excellent fingerprint image.

The specific embodiments proposed in the detailed description of the preferred embodiments are only used to facilitate the description of the technical content of the present invention, rather than restricting the present invention to the above embodiments in a narrow sense, and do not exceed the spirit of the present invention and the scope of the patent application. Under the circumstance, the various changes and implementations made belong to the scope of this new model.

d: aperture

H: thickness

P: Center spacing

t: thickness

F: Object

L1: Forward light

L2: Oblique light

10: Sensing substrate

11: The first light sensor element

12: The second light sensor element

13: Glass substrate

20: Optical module layer

21: The first light hole

22: second light hole

25: shading layer

26: Transparent support layer

40: Micro lens

41: The first micro lens

42: second micro lens

100: Optical biometric sensor

Claims (12)

An optical biometric sensor, including at least: A sensing substrate having a first light sensing element and a second light sensing element adjacent to each other; A light module layer includes at least: a light-shielding layer located on the sensing substrate and comprising a first light hole and a second light hole adjacent to each other; and a light-transmitting support layer on the light-shielding layer and In the first light hole and the second light hole; and A plurality of microlenses are located on the light module layer, wherein the microlenses include a first microlens and a second microlens that are adjacent to each other, and the first microlens focuses a forward light from an object through The light module layer and the first light hole reach the first light sensing element, and the light shielding layer has a predetermined thickness so that an oblique light from the object passes through the second microlens and the light module layer And hit the light shielding layer, but will not enter the first light hole and the first light sensing element, wherein the predetermined thickness of the light shielding layer is t, the aperture of the first light hole is d, and the light The thickness of the module layer is H, and the center distance between the first microlens and the second microlens is P, where (t/d)>0.3*(H/P), t<H, and d<P. The optical biometric sensor according to claim 1, wherein the light shielding layer has a solid structure cross section along the predetermined thickness direction. The optical biometric sensor according to claim 1, wherein 2*(H/P)>(t/d)>0.3*(H/P). The optical biometric sensor according to claim 1, wherein (t/d)=(H/P). The optical biometric sensor according to claim 1, wherein the light shielding layer has a cross section of a hollow structure along the direction of the predetermined thickness. The optical biometric sensor according to claim 5, wherein the light shielding layer at least includes: A first light-shielding film located on the sensing substrate and having a first sub-aperture and a second sub-aperture adjacent to each other; and A second light-shielding film is located above the first light-shielding film and has a third sub-aperture and a fourth sub-aperture adjacent to each other. The first photo-aperture includes the first sub-aperture and the third sub-aperture. A light hole, the second light hole includes the second sub-hole and the fourth sub-hole, and the farthest distance between the first light-shielding film and the second light-shielding film is equal to the predetermined thickness. The optical biometric sensor according to claim 6, wherein the aperture of the first sub-aperture is d1, the aperture of the third sub-aperture is d2, and the aperture d of the first aperture is defined as d1 and The average value of d2, where t/[(d1+d2)/2]>0.3*(H/P), t<H, d1<P and d2<P. The optical biometric sensor according to claim 7, wherein 2*(H/P)>t/[(d1+d2)/2]=0.3*(H/P). The optical biometric sensor according to claim 7, wherein t/[(d1+d2)/2]=(H/P). The optical biometric sensor according to claim 1, wherein the sensing substrate at least includes a glass substrate, and the first light sensing element and the second light sensing element are formed on the glass substrate. The optical biometric sensor according to claim 10, wherein the glass substrate is one of two opposing transparent substrates of a display. The optical biometric sensor according to claim 1, wherein the sensing substrate includes at least one semiconductor substrate, and the first light sensing element and the second light sensing element are formed on the semiconductor substrate.

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