TW201909026A - Image capture device - Google Patents

Abstract

An image capturing apparatus including a cover plate, a light source, a sensor, and a collimator is provided. The light source and the sensor are located on the same side of the cover plate. The collimator is disposed between the cover plate and the sensor, and the collimator includes collimating elements overlapped with each other. Each collimating element includes a transparent substrate and a light absorbing layer disposed on the transparent substrate. The light absorbing layer includes a plurality of light passing openings. The light passing openings expose sensing areas of the sensor. Spacing between the light passing openings is S. A width of each light passing opening is W, and W < S. A transparent substrate thickness of a first collimating element in the collimating elements is T1. A transparent substrate thickness of a second collimating element in the collimating elements is T2. The image capturing apparatus satisfies:.

Description

Imaging device

The present invention relates to a photoelectric device, and more particularly to an image capturing device.

Types of biometrics include face, voice, iris, retina, vein, palm print, and fingerprint recognition. According to different sensing methods, biometric identification devices can be divided into optical, capacitive, ultrasonic, and thermal sensing. Generally, an optical biometric identification device includes a light source, a light guide element, and a sensor. The light beam emitted by the light source illuminates the object to be identified pressed on the light guide element. The sensor receives the light beam reflected by the object to be identified for identification of biological characteristics. During the process of image pickup by the sensor, the light beam reflected by the fingerprint is easily scattered to the sensor, resulting in poor image acquisition quality and affecting the identification result. Although the existing technology improves the image acquisition quality, it is still difficult to effectively improve the crosstalk problem by the current technology improvement.

The invention provides an image capturing device, which has good identification ability.

An image capturing device of the present invention includes a cover plate, a light source, a sensor, and a collimator. The sensor is arranged next to the light source. The light source and the sensor are located on the same side of the cover. The collimator is disposed between the cover plate and the sensor, and the collimator includes a plurality of collimating elements overlapping each other. Each of the plurality of collimating elements includes a light-transmitting substrate and a light-absorbing layer disposed on the light-transmitting substrate. The light absorbing layer includes a plurality of light transmitting openings. The plurality of light-transmitting openings expose a plurality of sensing regions of the sensor. The distance between the plurality of transparent openings is S. The width of each of the plurality of light-transmitting openings is W, and W <S. The thickness of the transparent substrate of the first collimating element among the plurality of collimating elements is T1. The thickness of the light-transmitting substrate of the second collimating element of the plurality of collimating elements is T2. The imaging device meets: .

In an embodiment of the present invention, a plurality of depressions are formed on a surface of the light-transmitting substrate, and the light-absorbing layer is disposed in the plurality of depressions of the light-transmitting substrate.

In an embodiment of the present invention, the imaging device satisfies: .

In an embodiment of the present invention, the imaging device satisfies: .

In an embodiment of the invention, the first collimating element is disposed between the second collimating element and the sensor.

In an embodiment of the present invention, the second collimating element is disposed between the first collimating element and the sensor.

In an embodiment of the present invention, the second collimating element includes n light-transmitting substrates overlapping each other, the thickness of the n light-transmitting substrates is less than T1, and the total thickness of the n light-transmitting substrates is T2.

In an embodiment of the invention, the image capturing device further includes a display panel. The display panel is arranged between the cover and the collimator.

In an embodiment of the invention, the image capturing device further includes a band-pass filter layer. The band-pass filter layer is disposed between the display panel and the sensor, wherein the light emission spectrum of the light source falls within the transmission spectrum of the band-pass filter layer.

In an embodiment of the invention, the display panel is an organic light emitting diode display panel.

In an embodiment of the invention, the image capturing device further includes an adhesive layer. The adhesive layer is disposed between the plurality of light-transmitting substrates.

Based on the above, in the image pickup device according to the embodiment of the present invention, The design allows large-angle beams to be absorbed by the light absorbing layer through multiple reflections between multiple collimating elements, thereby effectively improving the problem of crosstalk and enabling the image pickup device to have a good discrimination ability.

In order to make the above features and advantages of the present invention more comprehensible, embodiments are hereinafter described in detail with reference to the accompanying drawings.

FIG. 1 is a schematic cross-sectional view of an image capturing apparatus according to a first embodiment of the present invention. FIG. 2 is a schematic top view of the collimator in FIG. 1. Please refer to FIG. 1 and FIG. 2. The image capturing device 100 according to the first embodiment of the present invention is adapted to capture biological characteristics of the object 10 to be measured. For example, the object to be measured 10 is a finger, and the biological characteristic is a fingerprint or a vein, but not limited thereto. In one embodiment, the test object 10 may be a palm, and the biological feature may be a palm print.

The image capturing device 100 includes a cover plate 110, a light source 120, a sensor 130, and a collimator 140. The sensor 130 is disposed beside the light source 120. The light source 120 and the sensor 130 are located on the same side of the cover plate 110. The collimator 140 is disposed between the cover plate 110 and the sensor 130, and the collimator 140 can be fixed on the cover plate 110 and the sensor by an adhesive layer (not shown) or a fixing mechanism (not shown). Between 130.

The cover plate 110 is adapted to protect the components underneath it, which may be a glass substrate or a plastic substrate. The glass substrate may be a chemically or physically strengthened glass substrate or an unreinforced glass substrate. The plastic substrate can be polycarbonate (PC), polyethylene terephthalate (PET), polymethylmethacrylate (PMMA), or polyimide (PI), etc. , But not limited to this.

The cover plate 110 has an inner surface SI and an outer surface SO opposite to the inner surface SI. The inner surface SI of the cover plate 110 is the surface of the cover plate 110 facing the sensor 130, and the outer surface SO of the cover plate 110 is the contact surface of the object to be measured 10. That is, the object under test 10 touches the outer surface SO of the cover plate 110 to perform biometric identification.

The light source 120 is adapted to provide a light beam B that illuminates the object 10 to be measured. The light source 120 may include a plurality of light emitting elements 122. Each light emitting element 122 emits a light beam B toward the test object 10. The plurality of light emitting elements 122 may include a light emitting diode, a laser diode, or a combination of the two. In addition, the light beam B may include visible light, non-visible light, or a combination of the two. Invisible light may be infrared light, but it is not limited to this.

The sensor 130 is adapted to receive a portion of the light beam B reflected by the object 10 (ie, the light beam B1 with fingerprint pattern information). The sensor 130 may include a Charge Coupled Device (CCD), a Complementary Metal-Oxide Semiconductor (CMOS), or other appropriate types of image sensing devices.

In one embodiment, a pulse width modulation circuit may be integrated in the sensor 130. By controlling the light emitting time of the plurality of light emitting elements 122 and the image capturing time of the sensor 130 through the pulse width modulation circuit, the light emitting time of the plurality of light emitting elements 122 and the image capturing time of the sensor 130 are synchronized, and the accuracy can be achieved The effect of control, but not limited to this.

The collimator 140 is adapted to collimate a portion of the light beam B reflected by the object to be measured 10 and transmitted toward the sensor 130. The collimator 140 includes a plurality of collimating elements that overlap each other. In this embodiment, the collimator 140 includes two collimation elements such as a first collimation element 142 and a second collimation element 144, and the first collimation element 142 is disposed between the second collimation element 144 and the sensor. Between 130. However, the number of collimating elements in the collimator 140 and the mutual configuration relationship between the plurality of collimating elements may be changed according to requirements, and are not limited to those shown in FIG. 1.

Each of the plurality of collimating elements includes a light-transmitting substrate and a light-absorbing layer disposed on the light-transmitting substrate. For example, the first collimating element 142 includes a light-transmitting substrate 1421 and a light-absorbing layer 1422. The light-absorbing layer 1422 is disposed on the surface S1421S of the light-transmitting substrate 1421 facing the sensor 130 and is located on the light-transmitting substrate 1421 and the sensor 130. between. The second collimating element 144 includes a light-transmitting substrate 1441, a light-absorbing layer 1442, and a light-absorbing layer 1443. The light-absorbing layer 1442 is disposed on the surface S1441S of the light-transmitting substrate 1441 facing the sensor 130, and is located on the light-transmitting substrate 1441 and the light-transmitting substrate 1421. The light absorbing layer 1443 is disposed on the surface S1441C of the light-transmitting substrate 1441 facing the cover 110 and is located between the cover 110 and the light-transmitting substrate 1441.

It should be noted that the number of light-transmitting substrates in each collimating element, the number of light-absorbing layers, the relative configuration relationship between the light-transmitting substrate and the light-absorbing layer, and the method of forming the light-absorbing layer can be changed as required, and not shown in FIG. 1 Limited. A plurality of depressions C are formed on the surface S1441S of the light-transmitting substrate 1441, and the light absorption layer 1442 is disposed in the plurality of depressions C of the light-transmitting substrate 1441, so that the outer surface T1442 and the surface S1441S of the light-absorbing layer 1442 are not formed with a plurality of depressions C. The parts are flush. The method of forming the light absorbing layer 1442 may include the following steps. First, a plurality of depressions C are formed on the surface S1441S of the light-transmitting substrate 1441. Next, a light absorbing material is formed in the plurality of depressions C. Then, the light absorbing material is cured to form a light absorbing layer 1442. In an embodiment, the light-transmitting substrate 1441 and the plurality of recesses C thereof may be formed by die casting, and the step of forming the plurality of recesses C may be omitted.

Among the collimating elements, the light-transmitting substrate (such as the light-transmitting substrate 1421 and the light-transmitting substrate 1441) provides a bearing surface of the light-absorbing layer (such as the light-absorbing layer 1422, the light-absorbing layer 1442, and the light-absorbing layer 1443), which can be a glass substrate or a plastic Substrate. The light absorbing layer is used to absorb the large-angle light beams (such as the light beams B2 and B3) in the part of the light beam B reflected by the object to be measured 10, so as to achieve the effect of collimating the light beams transmitted to the sensor 130. The light absorbing layer has high absorptivity and low reflectivity to reduce the ratio of the light beam transmitted to the light absorbing layer to be reflected by the light absorbing layer and the number of times the light beam is reflected by the light absorbing layer, thereby effectively reducing the ratio of the large angle light beam received by the sensor 130. The low reflectance means that the reflectance is lower than 10% in the visible light band and the infrared light band. For example, the light-absorbing layer may be a low reflectivity ink, but is not limited thereto.

In addition, in order that the portion of the light beam B reflected by the object to be measured 10 (such as the light beam B1) can be received by the sensor 130, the light absorption layer includes a plurality of light-transmitting openings O. The plurality of light-transmitting openings O expose the plurality of sensing regions 132 of the sensor 130. Specifically, the plurality of light-transmitting openings O of the light-absorbing layer 1422, the light-absorbing layer 1442, and the light-absorbing layer 1443 are disposed corresponding to the plurality of sensing regions 132 of the sensor 130. Here, the plurality of sensing regions 132 may be positions of a plurality of charge-coupled devices or a plurality of pixel regions of a complementary metal oxide semiconductor device.

The distance between the plurality of transparent openings O is S. The width of each of the plurality of light-transmitting openings O is W, and W <S. The thickness of the transparent substrate of the first collimating element 142 is T1. The thickness of the transparent substrate of the second collimating element 144 is T2. The image capturing device 100 satisfies: . Here, the thickness of the light-transmitting substrate of the collimating element refers to the total thickness of all light-transmitting substrates in the collimating element. In this embodiment, the first collimating element 142 includes only one transparent substrate (ie, the transparent substrate 1421), and the second collimating element 144 includes only one transparent substrate (ie, the transparent substrate 1441). Therefore, the thickness T1 of the transparent substrate of the first collimating element 142 is the thickness of the transparent substrate 1421, and the thickness T2 of the transparent substrate of the second collimating element 144 is the thickness of the transparent substrate 1441.

By The design can make large-angle beams (such as beams B2 and B3) be absorbed by the light-absorbing layer through multiple reflections between multiple collimating elements, thereby effectively improving the crosstalk problem and making the imaging device 100 have good identification. ability. In one embodiment, if the image capturing device 100 satisfies The design can further reduce the ratio of the large-angle beam received by the sensor 130, effectively improve the signal-to-noise ratio, and help the back-end identify signals and noise, thereby improving the success rate of identification. In another embodiment, if the image capturing device 100 satisfies , The signal-to-noise ratio can approach 0.

Next, other embodiments of the image capturing device will be described with reference to FIGS. 3 to 5. The same components are denoted by the same reference numerals, and will not be described again below. 3 to 5 are schematic cross-sectional views of an image capturing device according to the second embodiment to the fourth embodiment of the present invention, respectively.

Referring to FIG. 3, the main differences between the image capturing device 200 of the second embodiment of the present invention and the image capturing device 100 of FIG. 1 are as follows. In the image capturing device 200, the second collimating element 144 is disposed between the first collimating element 142 and the sensor 130. Further, the light absorbing layer 1422 of the first collimation element 142 is disposed on a surface S1421C of the transparent substrate 1421 facing the cover plate 110 and is located between the transparent substrate 1421 and the cover plate 110. The light absorbing layer 1442 of the second collimating element 144 is disposed on a surface S1441C of the transparent substrate 1441 facing the cover plate 110 and is located between the transparent substrate 1441 and the transparent substrate 1421. The light absorbing layer 1443 of the second collimating element 144 is disposed on a surface S1441S of the transparent substrate 1441 facing the sensor 130 and is located between the sensor 130 and the transparent substrate 1441. A plurality of depressions C are formed on the surface S1441C of the light-transmitting substrate 1441, and the light absorption layer 1442 is disposed in the plurality of depressions C of the light-transmitting substrate 1441, so that the outer surface T1442 and the surface S1441C of the light-absorbing layer 1442 are not formed with a plurality of depressions C. The parts are flush.

Please refer to FIG. 4. The main differences between the image capturing device 300 according to the third embodiment of the present invention and the image capturing device 100 of FIG. 1 are as follows. In the image capturing device 300, in addition to the light-transmitting substrate 1441, the light-absorbing layer 1442, and the light-absorbing layer 1443, the second collimating element 144 further includes a light-transmitting substrate 1444 and a light-absorbing layer 1445. In this embodiment, the light-transmitting substrate 1444 is located between the light-transmitting substrate 1441 and the cover plate 110, the light-absorbing layer 1443 is located between the light-transmitting substrate 1441 and the light-transmitting substrate 1444, and the light-absorbing layer 1443 and the light-absorbing layer 1445 are respectively located in light-transmitting The substrate 1444 is on two opposite surfaces. A plurality of depressions C are formed on the surface S1444S of the light-transmitting substrate 1444 facing the sensor 130, and the light-absorbing layer 1443 is disposed in the plurality of depressions C of the light-transmitting substrate 1444, so that the outer surface T1443 and the surface S1444S of the light-absorbing layer 1443 are not formed. The portion having the plurality of depressions C is flush.

The thickness T2A of the transparent substrate 1441 and the thickness T2B of the transparent substrate 1444 are smaller than T1, and the sum of the thickness T2A and the thickness T2B is T2. That is, T2A + T2B = T2. In addition, the thickness T2A and the thickness T2B may be the same or different. In another embodiment, the second collimating element 144 may include two or more transparent substrates and three or more light absorbing layers. Similarly, the first collimating element 142 may include one or more light-transmitting substrates and two or more light-absorbing layers, and the thickness T1 of the light-transmitting substrate of the first collimating element 142 is the sum of the thicknesses of the light-transmitting substrates of one or more layers .

It is added that the second collimating element 144 of the image capturing device 200 in FIG. 3 can also be improved with this embodiment, and will not be repeated here.

Referring to FIG. 5, the main differences between the image capturing device 400 of the fourth embodiment of the present invention and the image capturing device 100 of FIG. 1 are as follows. In the image capturing device 400, the image capturing device 400 further includes a display panel 410 and a band-pass filter layer 420. The display panel 410 is disposed between the cover plate 110 and the collimator 140 and is adapted to provide an image frame. For example, the display panel 410 may be a Thin Film Transistor Liquid Crystal Display panel (TFT-LCD panel), a Micro Light Emitting Diode display panel, or a Micro LED display panel. Or organic light emitting diode display panel (Organic Light Emitting Diode display panel, OLED display panel), but not limited to this.

The band-pass filter layer 420 is disposed between the collimator 140 and the sensor 130 (not shown) or between the display panel 410 and the collimator 140, and is used to pass the light beam from the light source 120 and filter other light beams. In order to avoid the interference caused by the ambient light beam or the light beam from the display panel 410 being transmitted to the sensor 130, the identification ability of the electronic device 400 is further improved. For example, the bandpass filter layer 420 may be an infrared bandpass filter layer, which allows a light beam with a wavelength of 800 nm to 900 nm to pass, and filters a light beam with a wavelength other than 800 nm to 900 nm. Correspondingly, the light source 120 is an infrared light source with a wavelength in the range of 800 nm to 900 nm. In other embodiments, the bandpass filter layer 420 may be a bandpass filter layer that allows a light beam with a wavelength of 840 nm to 860 nm or a light beam with a wavelength of 890 nm to 990 nm to pass, and the light source 120 is selected to have a wavelength of 840. An infrared light source in a range of nm to 860 nm or 890 nm to 990 nm, but the present invention is not limited thereto.

It is added that the image capturing device 200 in FIG. 3 and the image capturing device 300 in FIG. 4 may further include a display panel 410 and a band-pass filter layer 420, which will not be repeated here.

In the above embodiment, a plurality of collimating elements may be fixed together through an adhesive layer (not shown) or a fixing mechanism (not shown). For example, an adhesive layer may be formed between a plurality of transparent substrates of a plurality of collimating elements, so that the plurality of collimating elements are firmly fixed together, but not limited thereto. The adhesive layer may be an optical clear adhesive (OCA) or a die attach film (DAF), but is not limited thereto.

In summary, in the image pickup device according to the embodiment of the present invention, The design allows large-angle beams to be absorbed by the light absorbing layer through multiple reflections between multiple collimating elements, thereby effectively improving the problem of crosstalk and enabling the image pickup device to have a good discrimination ability. In one embodiment, the image capturing device may further include a display panel to have functions of biometric identification and display. In another embodiment, the light source of the image capturing device may be an infrared light source, and the image capturing device may further include an infrared bandpass filter layer to avoid interference caused by the ambient light beam or the light beam from the display panel transmitted to the sensor. , Thereby improving the recognition ability of the electronic device.

Although the present invention has been disclosed as above with the examples, it is not intended to limit the present invention. Any person with ordinary knowledge in the technical field can make some modifications and retouching without departing from the spirit and scope of the present invention. The protection scope of the present invention shall be determined by the scope of the attached patent application.

10‧‧‧ DUT

100, 200‧‧‧ image taking device

300, 400‧‧‧ image taking device

110‧‧‧ cover

120‧‧‧ light source

122‧‧‧Light-emitting element

130‧‧‧Sensor

132‧‧‧Sensing area

140‧‧‧Collimator

142‧‧‧First collimation element

144‧‧‧Second collimation element

410‧‧‧Display Panel

420‧‧‧ Bandpass Filter

1421, 1441, 1444‧‧‧‧Transparent substrate

1422, 1442‧‧‧ light absorption layer

1443, 1445‧‧‧Light absorption layer

B, B1, B2, B3‧‧‧ Beams

C‧‧‧ Depression

O‧‧‧Translucent opening

S‧‧‧Pitch

SI‧‧‧Inner surface

SO, T1442, T1443‧‧‧ Outer surface

S1421S, S1421C‧‧‧Surface

S1441S, S1441C, S1444S‧‧‧Surface

T1, T2‧‧‧‧Transparent substrate thickness

T2A, T2B‧‧‧thickness

W‧‧‧Width

FIG. 1 is a schematic cross-sectional view of an image capturing apparatus according to a first embodiment of the present invention. FIG. 2 is a schematic top view of the collimator in FIG. 1. 3 to 5 are schematic cross-sectional views of an image capturing device according to the second embodiment to the fourth embodiment of the present invention, respectively.

Claims (11)

An image capturing device includes: a cover plate; a light source; a sensor disposed next to the light source, and the light source and the sensor are located on the same side of the cover plate; and a collimator disposed on the Between the cover plate and the sensor, and the collimator includes a plurality of collimating elements overlapping each other, wherein each of the collimating elements includes a light-transmitting substrate and a light-absorbing member disposed on the light-transmitting substrate Layer, and the light absorbing layer includes a plurality of light-transmitting openings, the light-transmitting openings expose a plurality of sensing regions of the sensor, and a distance between the light-transmitting openings is S, and The width is W, and W <S. The thickness of the light-transmitting substrate of a first collimating element among the collimating elements is T1, and the thickness of the light-transmitting substrate of a second collimating element among the collimating elements is T2. , And the imaging device meets: . The image capturing device according to item 1 of the scope of patent application, wherein a plurality of depressions are formed on one surface of the light-transmitting substrate, and the light-absorbing layer is disposed in the depressions of the light-transmitting substrate. The imaging device according to item 1 of the scope of patent application, wherein the imaging device satisfies: . The imaging device according to item 1 of the scope of patent application, wherein the imaging device satisfies: . The image capturing device according to item 1 of the scope of patent application, wherein the first collimating element is disposed between the second collimating element and the sensor. The image capturing device according to item 1 of the scope of patent application, wherein the second collimating element is disposed between the first collimating element and the sensor. The image capturing device according to item 1 of the patent application scope, wherein the second collimating element includes n light-transmitting substrates overlapping each other, the thickness of the n light-transmitting substrates is less than T1, and the n light-transmitting The total thickness of the substrate is T2. The image capturing device according to item 1, 3, or 4 of the scope of patent application, further includes: a display panel disposed between the cover plate and the collimator. The image capturing device according to item 8 of the scope of patent application, further comprising: a band-pass filter layer disposed between the display panel and the sensor, wherein the emission spectrum of the light source falls on the band-pass filter layer Within the transmission spectrum. The image capturing device according to item 8 of the scope of patent application, wherein the display panel is an organic light emitting diode display panel. The image capturing device according to item 7 of the patent application scope further includes: an adhesive layer disposed between the transparent substrates.