WO2023056632A1

WO2023056632A1 - Image sensor and electronic device

Info

Publication number: WO2023056632A1
Application number: PCT/CN2021/122861
Authority: WO
Inventors: 文龙; 陈沁�; 刘永俊; 杨亮
Original assignee: 华为技术有限公司
Priority date: 2021-10-09
Filing date: 2021-10-09
Publication date: 2023-04-13
Also published as: CN117561602A

Abstract

Embodiments of the present application disclose an image sensor and an electronic device. The image sensor comprises at least two pixel structures, the at least two pixel structures being used to absorb two types of incident light having different characteristics, respectively. Each pixel structure comprises a metal layer, a first dielectric layer and a nano-antenna layer, the first dielectric layer being located at one side of the metal layer, the first dielectric layer comprises a photosensitive material, the nano-antenna layer the located at a side of the first dielectric layer distant from the metal layer, and a thickness of the first dielectric layer being less than one-fifth of the minimum wavelength of incident light in the wavelength band absorbed by the pixel structure. At least one side length of the pixel structure is smaller than the maximum wavelength of incident light absorbed by the pixel structure. Using embodiments of the present application, a light sensitivity of a pixel can be effectively increased. Furthermore, low crosstalk and wide photosensitive angle can be maintained, and a super-resolution small pixel can also be attained.

Description

Image Sensors and Electronics

technical field

The present application relates to the field of electronic technology, in particular to an image sensor and electronic equipment.

Background technique

Image sensors, which convert light signals into electrical signals, are one of the core parts of mobile phone cameras. Image sensors can take advantage of the particle nature of light, allowing photons to excite free electrons in semiconductors to generate electrical signals.

In some scenarios, for example, in order to detect multiple colors of light, an image sensor usually sets a corresponding color filter above the pixel structure, so that the pixel can only detect the light passed through the filter. However, this will Most of the light is filtered out by the filter, reducing the photosensitivity. In addition, the crosstalk problem will also increase with the size reduction, hindering the reduction of the pixel size.

Contents of the invention

Embodiments of the present application provide an image sensor and an electronic device. The embodiment of the present application can increase the photosensitive intensity, maintain low crosstalk and wide photosensitive angle, and can also realize super-resolution small-sized pixels.

In the first aspect, an embodiment of the present application provides an image sensor, including at least two pixel structures, the at least two pixel structures are respectively used to absorb two types of incident light with different characteristics, and each of the pixel structures includes a metal layer , a first dielectric layer and a first dielectric layer, the first dielectric layer is located on one side of the metal layer, and the first dielectric layer includes a photosensitive material. The nano-antenna layer is located on the side of the first dielectric layer away from the metal layer, and the nano-antenna layer includes one or more nano-antennas, and each of the nano-antennas is used to absorb a waveband or a polarization incident light. Wherein, the thickness of the first medium layer is less than one-fifth of the minimum wavelength of the incident light absorbed by the pixel structure, and at least one side length of the pixel structure is less than the maximum wavelength of the incident light absorbed by the pixel structure. wavelength. Wherein, the nano-antenna layer can select incident light with different characteristics, and can enhance the absorption of incident light. The first medium layer can photoelectrically convert incident light absorbed by the nano-antenna layer to output electrical signals. The metal layer can enhance the absorption of incident light by the nano-antenna layer. The photosensitive material of the embodiment of the present application can be used for photoelectric conversion.

The image sensor of the embodiment of the present application can absorb two kinds of incident light with different characteristics, and the thickness of the first medium layer is set to be less than one-fifth of the minimum wavelength of the incident light absorbed by the pixel structure, and the pixel structure The length of at least one side of the nano-antenna is set to be smaller than the maximum wavelength of the absorbed light, so that the light-splitting effect of the nano-antenna can be realized, the photosensitive intensity can be increased, the crosstalk is kept low and the photosensitive angle is wide, and super-resolution small-sized pixels can also be realized. .

In a possible design, the two incident lights with different characteristics are incident lights with two different polarizations. Based on such a design, the image sensor can absorb incident light of different polarizations, thereby increasing the absorption rate of the incident light.

In a possible design, the one or more nano-antennas are dipole antennas, and the extension directions of the dipole antennas in the at least two pixel structures are different; or the one or more nano-antennas are For the helical antenna, the rotation directions of the helical antennas in the at least two pixel structures are different. In the embodiments of the present application, the nano-antennas can be used in various ways, and the antenna polarization directions of the nano-antennas in the two pixel structures are different, which can increase the absorption rate of light with different polarizations and improve the light utilization rate.

In a possible design, the two incident lights with different characteristics are incident lights of two different wavelength bands. Based on such a design, the image sensor can absorb incident light of different wavelength bands to increase the absorption rate of incident light.

In a possible design, the pixel structure further includes a second dielectric layer, the second dielectric layer is located between the nano-antenna layer and the first dielectric layer, and the second dielectric layer includes a non-photosensitive material . Based on such a design, the embodiment of the present application can enhance the photosensitive intensity, further enhance the light absorption rate of the nano-antenna layer, and reduce the loss of light absorbed by the nano-antenna.

In a possible design, the thickness of the second dielectric layer is smaller than the thickness of the first dielectric layer. Based on such a design, the embodiment of the present application can enhance the photosensitive intensity, further enhance the light absorption rate of the nano-antenna layer, and reduce the loss of light absorbed by the nano-antenna.

In a possible design, the thickness of the second dielectric layer is 10%-70% of the thickness of the first dielectric layer. The embodiment of the present application can enhance the photosensitive intensity, further enhance the light absorption rate of the nano-antenna layer, and reduce the loss of light absorbed by the nano-antenna.

In a possible design, the at least two pixel structures are adjacent. In the embodiments of the present application, the nano-antennas can be used in various ways, and the antenna polarization directions of the nano-antennas in two adjacent pixel structures are different, which can increase the absorption rate of light with different polarizations and improve the light utilization rate.

In a possible design, the image sensor further includes one or more first electrode lines, the one or more first electrode lines are in contact with the upper surface of the first dielectric layer, and the one or more The multiple first electrode lines are used to receive electrical signals output by the at least two pixel structures, and the electrical signals are used to obtain an image. In the embodiments of the present application, the output signals of each pixel structure can be transmitted through the electrode lines, so as to obtain the output of the image sensor.

In a possible design, the one or more first electrode lines are in contact with the upper surface of the first dielectric layer, and the first electrode lines are electrically connected to the nanoantennas in the same row or column. In the embodiments of the present application, the output signals of each pixel structure can be transmitted through the electrode lines, so as to obtain the output of the image sensor.

In a possible design, the first electrode wire is electrically connected to the center of the nano-antenna. The first electrode wire in the embodiment of the present application may be integrally formed with the nano-antenna. In the embodiment of the present application, the output signal of each photosensitive pixel can be transmitted through the electrode line, so as to obtain the output of the image sensor. In the embodiments of the present application, the output signals of each pixel structure can be transmitted through the electrode lines, so as to obtain the output of the image sensor.

In a possible design, the image sensor further includes one or more second electrode lines, the one or more second electrode lines are in contact with the lower surface of the first dielectric layer, and the one or more second electrode lines are in contact with the lower surface of the first dielectric layer. The multiple second electrode lines are used to receive electrical signals output by the at least two pixel structures, and the electrical signals are used to obtain an image.

In a possible design, the image sensor includes a plurality of pixel structure sets arranged periodically, and the pixel structure set includes the at least two pixel structures; at least one side length of the pixel structure set is less than or equal to the half of the minimum wavelength of incident light absorbed by the at least two pixel structures. For example, the pixel structures in the pixel structure set may include three pixel structures arranged in a line, and the three pixel structures are respectively three pixel structures for absorbing red light, green light and blue light. The pixel structures in the pixel structure set may also include four pixel structures arranged in a square shape, and the four pixel structures may be used to absorb red light, green light, green light and blue light respectively.

In a second aspect, an embodiment of the present application further provides an electronic device, where the electronic device includes the above-mentioned image sensor.

Using the image sensor and electronic device of the embodiment of the present application, the image sensor of the embodiment of the present application can absorb two types of incident light with different characteristics, and the thickness of the first medium layer is set to be smaller than the incident light absorbed by the pixel structure One-fifth of the minimum wavelength of the pixel structure, and at least one side length of the pixel structure is set to be smaller than the maximum wavelength of the absorbed light, so that the light-splitting effect of the nano-antenna can be realized, the photosensitive intensity can be increased, and the crosstalk and The wider light-sensitive angle can also realize super-resolution small-size pixels. In the embodiment of the present application, the image sensor can realize high-efficiency ultra-thin light-sensing, and can support flexible, curved and other devices.

Description of drawings

FIG. 1 is a schematic structural diagram of an electronic device provided by an embodiment of the present application.

FIG. 2 is a schematic structural diagram of a camera provided by an embodiment of the present application.

FIG. 3 is a schematic structural diagram of an image sensor provided by an embodiment of the present application.

FIG. 4 is another schematic structural diagram of an image sensor according to an embodiment of the present application.

FIG. 5 is another structural schematic diagram of an image sensor according to an embodiment of the present application.

FIG. 6 is another schematic structural diagram of an image sensor according to an embodiment of the present application.

Fig. 7a and Fig. 7b are schematic structural diagrams of the nano-antenna according to the embodiment of the present application.

FIG. 8a and FIG. 8b are structural schematic diagrams of a pixel structure set according to an embodiment of the present application.

FIG. 9 is another schematic structural diagram of an image sensor according to an embodiment of the present application.

FIG. 10 is another schematic structural diagram of an image sensor according to an embodiment of the present application.

FIG. 11 is another structural schematic diagram of the nano-antenna according to the embodiment of the present application.

FIG. 12 is another structural schematic diagram of the nano-antenna according to the embodiment of the present application.

FIG. 13 is another structural schematic diagram of the nano-antenna according to the embodiment of the present application.

14a-14c are application state diagrams of the image sensor of the embodiment of the present application.

Description of main component symbols

Electronic equipment 100

Processor 110

External Memory Interface 120

Internal memory 121

USB interface 130

Charging Management Module 140

Power Management Module 141

Battery 142

Antenna 1, 2

Mobile communication module 150

Wireless communication module 160

Audio module 170

Speaker 170A

Receiver 170B

Microphone 170C

Headphone Jack 170D

Sensor Module 180

Pressure sensor 180A

Gyro Sensor 180B

Barometric pressure sensor

Magnetic sensor 180D

Acceleration sensor 180E

Distance sensor 180F

Proximity light sensor 180G

Fingerprint sensor 180H

Temperature sensor 180J

Touch Sensor 180K

Ambient Light Sensor 180L

Bone conduction sensor 180M

Buttons 190

Motor 191

Indicators 192

Camera 193

Display Screen 194

SIM card interface 195

Camera 200

Lens 201

Aperture 202

Image sensor 203

Analog Preprocessor 204

Modulus sensor 205

Digital Signal Processor 206

System Controller 207

Data bus 208

Memory 209

Display 210

Pixel Structure

10, 10a, 10b, 10c, 10d, 10e, 10f,

Nano antenna layer

12, 12a, 12b, 12c

Nano Antennas

121, 121b, 121c, 121d, 121e, 121f,

The first electrode wire 122

Second electrode wire 123

The

first dielectric layer

14, 14a, 14b, 14c

Metal layer

16, 16a, 16b, 16c

Second Dielectric Layer 18

Collection of Pixel Structures 20

The following specific embodiments will further describe the present application in detail in conjunction with the above-mentioned drawings.

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present application with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of them.

In the embodiment of the present application, terms such as "first" and "second" are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance, nor can they be understood as indicating or implying order. For example, the first application, the second application, etc. are used to distinguish different applications, rather than to describe the specific order of applications, and the features defined as "first" and "second" may explicitly or implicitly include one or More of this feature. In the description of the embodiments of the present application, words such as "exemplary" or "for example" are used as examples, illustrations or descriptions. Any embodiment or design solution described as "exemplary" or "for example" in the embodiments of the present application shall not be construed as being more preferred or more advantageous than other embodiments or design solutions. Rather, the use of words such as "exemplary" or "such as" is intended to present related concepts in a concrete manner.

With the rapid development of the electronics industry, multi-color image sensors are increasingly used in consumer products and autonomous driving. Image sensors can take advantage of the particle nature of light, allowing photons to excite free electrons in semiconductors to generate electrical signals. It can be understood that in some scenarios, the pixels of the image sensor only detect the light transmitted by the filter, resulting in weak light sensitivity.

In order to cope with the above-mentioned weak photosensitive ability, in a possible scenario, silicon nanowire antennas can be placed on the photosensitive layer of the image sensor, so that there is no need to set color filters above the pixel structure, because nanowires with different diameters There may be different resonant responses to light of different colors, whereby only light of the corresponding color is received. In the above scenario, due to the large aspect ratio of the silicon nanowire antenna, it is difficult to manufacture, and its large specific surface area causes extremely serious surface recombination effects, and the conversion efficiency of absorbed photons into electrons is usually low, resulting in low quantum efficiency and affecting Photosensitivity.

In another possible scenario, the image sensor can use the metasurface instead of the filter to adjust the phase of the incident light, so that the light of different colors is deflected to the pixel positions of different colors. In the above scenario, since the metasurface is sensitive to the angle of the incident light, the angle difference is large, and the severe spatial crosstalk leads to a large change in the back-end demosaic algorithm, and multi-wavelength multiplexing will also lead to low light splitting efficiency. In addition, the metasurface Both the light-splitting ability and the quality of the pixel depend on the arrangement of a sufficient number of phase structure units in space, and the pixel size cannot be too small.

To this end, the embodiments of the present application provide a pixel structure, an image sensor, and an electronic device. The embodiments of the present application can effectively improve the light-sensing ability of the pixel, and can maintain low crosstalk and a wide light-sensing angle without introducing angle Problems such as deviation, crosstalk, and manufacturing difficulty are too great, and it is also possible to achieve super-resolution small-size pixels and improve product competitiveness.

It can be understood that the pixel structure provided by the embodiments of the present application can be applied to electronic devices with a camera function such as mobile phones, tablet computers, and wearable devices, and the embodiments of the present application do not impose any restrictions on the specific types of electronic devices.

Exemplarily, FIG. 1 shows a schematic structural diagram of an electronic device 100 .

The electronic device 100 may include a processor 110, an external memory interface 120, an internal memory 121, a universal serial bus (universal serial bus, USB) interface 130, a charging management module 140, a power management module 141, a battery 142, an antenna 1, Antenna 2, mobile communication module 150, wireless communication module 160, audio module 170, speaker 170A, receiver 170B, microphone 170C, earphone jack 170D, sensor module 180, button 190, motor 191, indicator 192, camera 193, display screen 194 , and a subscriber identification module (subscriber identification module, SIM) card interface 195, etc. The sensor module 180 may include a pressure sensor 180A, a gyroscope sensor 180B, a pressure sensor 180C, a magnetic sensor 180D, an acceleration sensor 180E, a distance sensor 180F, a proximity light sensor 180G, a fingerprint sensor 180H, a temperature sensor 180J, a touch sensor 180K, an ambient light sensor 180L, bone conduction sensor 180M, and the like.

It can be understood that, the structure illustrated in the embodiment of the present application does not constitute a specific limitation on the electronic device 100 . In other embodiments of the present application, the electronic device 100 may include more or fewer components than shown in the illustration, or combine some components, or separate some components, or arrange different components. The illustrated components can be realized in hardware, software or a combination of software and hardware.

In some embodiments, the processor 110 communicates with the camera 193 through a CSI interface to realize the shooting function of the electronic device 100 . The electronic device 100 can realize the shooting function through the ISP, the camera 193 , the video codec, the GPU, the display screen 194 , and the application processor. The ISP is used for processing the data fed back by the camera 193 .

For example, when taking a picture, open the shutter, the light is transmitted to the photosensitive element of the camera through the lens, and the light signal is converted into an electrical signal, and the photosensitive element of the camera transmits the electrical signal to the ISP for processing, and converts it into an image visible to the naked eye. ISP can also perform algorithm optimization on image noise, brightness, and skin color. ISP can also optimize the exposure, color temperature and other parameters of the shooting scene. In some embodiments, the ISP may be set in the camera 193 . The camera 193 is used to capture still images or video. The object generates an optical image through the lens and projects it to the photosensitive element.

It can be understood that the photosensitive element may be a charge coupled device (charge coupled device, CCD) or a complementary metal-oxide-semiconductor (complementary metal-oxide-semiconductor, CMOS) phototransistor. The photosensitive element converts light signals into electrical signals, and then transmits the electrical signals to the ISP for conversion into digital image signals. The ISP outputs the digital image signal to the DSP for processing. The DSP converts digital image signals into image signals in standard RGB, YUV and other formats. In some embodiments, the electronic device 100 may include 1 or N cameras 193 , where N is a positive integer greater than 1.

It can be understood that the electronic device 100 may also be a detector, such as a spectral detector, which may be used for analyzing the material properties of an object, and the electronic device 100 may also include a photodetector, which is used for sensing the environment.

FIG. 2 is a schematic structural diagram of a camera 200 provided by an embodiment of the present application. The camera 200 can be set in the electronic device 100 shown in FIG. 1 to realize the function of the camera 193 . It can be understood that the camera 200 in this embodiment may include a lens 201, an aperture 202, an image sensor 203, an analog preprocessor 204, an analog-to-digital sensor 205, a digital signal processor 206, a system controller 207, a data bus 208, memory 209, display 210, etc. It can be understood that the structure illustrated in the embodiment of the present application does not constitute a specific limitation on the camera 200 . In other embodiments of the present application, the camera 200 may include more or fewer components than shown in the illustration, or combine certain components, or separate certain components, or arrange different components. The illustrated components can be realized in hardware, software or a combination of software and hardware.

It should also be understood that the structure illustrated in the embodiment of the present application does not constitute a specific limitation on the functions of the camera 200 . The functions of the camera 200 include the functions of existing cameras, and are not limited to functions such as taking pictures or taking videos. The lens 201 is a device for imaging an object on a sensor, and plays a role of light collection, and may be composed of several lenses. The aperture 202 is a device for controlling the light passing through the lens to the sensor. In addition to controlling the amount of light passing through, the aperture 202 also has the function of controlling the depth of field. Depth of field refers to the front and rear distance range of the subject measured by imaging that can obtain clear images in front of the camera lens. The larger the aperture, the smaller the depth of field. The image sensor 203 is a device for receiving light passing through the lens and converting these light signals into electrical signals.

In the embodiment of the present application, the image sensor 203 is composed of a pixel structure integrated with a nano-antenna and a metal-dielectric-metal sensor. The electrical signal generated by the image sensor 203 is an analog direct current signal, and the analog preprocessor 204 performs preprocessing on the analog direct current signal, and the preprocessing includes noise reduction processing, correction processing, and compensation processing. The analog-to-digital converter 205 is used to convert the preprocessed analog DC signal into a digital signal. The digital signal is sent to the digital signal processor 206 for processing. The system controller 207 controls the aperture 202 , the image sensor 203 , the analog pre-processor 204 and the analog-to-digital converter 205 . The processed digital signal is transmitted to the memory 209 or the display 210 via the data bus 208 . As an example but not a limitation, the storage 209 may be a photo storage such as a gallery of the electronic device 100 shown in FIG. 1 , and the display 210 may be the display screen 194 shown in FIG. 1 .

FIG. 3 is a schematic structural diagram of an image sensor according to an embodiment of the present application. The image sensor may be the image sensor 203 in FIG. 2 , and may implement all functions of the image sensor 203 . The image sensor 203 may be a pixel array, and may include multiple pixel structures, and the dotted lines represent pixel structures not shown. Since there is a nano-antenna layer in each pixel structure, the nano-antenna layer includes one or more nano-antennas, and the response of the nano-antenna to light may depend on the proportional relationship between the size of the nano-antenna and the wavelength of light.

Therefore, each pixel structure does not need to set up a filter structure, relying on the selectivity of the nano-antenna to the light wavelength, it can realize the absorption of light of different colors. It can be seen that, if the image sensor includes nano-antennas of L sizes, the image sensor can absorb light of L different wavelengths, where L can be an integer greater than or equal to 3.

It can be understood that an antenna is a device that can convert alternating current and electromagnetic waves into each other, light can be regarded as electromagnetic waves, and a nanoantenna is an optical antenna at the nanometer scale.

Please refer to FIG. 4 , which is a schematic diagram of an image sensor provided by an embodiment of the present application. It can be understood that the image sensor 203 may include at least two pixel structures 10 . Wherein, the at least two pixel structures can be used to absorb two types of incident light with different characteristics. For example, the at least two pixel structures 10 can be used to absorb incident light of different polarizations respectively. Alternatively, the at least two pixel structures 10 may be used to absorb incident light of different wavelength bands respectively.

Specifically in the implementation process of the present application, as shown in FIG. 4 , the pixel structure 10 in this embodiment may include a nano-antenna layer 12 , a first dielectric layer 14 and a metal layer 16 .

The nano-antenna layer 12 can be arranged on the top layer of the entire pixel structure 10, the metal layer 16 can be arranged on the bottom layer of the entire pixel structure 10, and the first dielectric layer 14 can be arranged on the middle layer of the entire pixel structure 10. , that is, the first dielectric layer 14 may be disposed between the nano-antenna layer 12 and the metal layer 16 .

Specifically, the nano-antenna layer 12 can select incident light with different characteristics, and can enhance the absorption of incident light. The first dielectric layer 14 may be located on one side of the metal layer 16, and the first dielectric layer 14 may include a photosensitive material for photoelectric conversion. In a possible implementation, the first dielectric layer 14 can be made of photosensitive material, and the first dielectric layer 14 can convert the incident light absorbed by the nano-antenna layer 12 to photoelectric conversion to output an electrical signal. The metal layer 16 can enhance the absorption of incident light by the nano-antenna layer 12 .

Due to the plasmon effect on the surface of the nanoantenna, the incident light of the corresponding wavelength band can be focused in a small area near the nanoantenna. It can be understood that the plasmonic effect can refer to that in a solid system with a certain carrier concentration (such as a metal, a semiconductor with a certain carrier concentration, etc.), due to the Coulomb interaction between carriers , so that the fluctuation of the carrier concentration in one place in the space will cause the oscillation of the carrier concentration in other places. This kind of meta-excitation, which is characterized by the oscillation of carrier concentration, is called the plasmon effect.

In the embodiment of the present application, the part of the incident light that resonates with the nano-antenna layer 12 is absorbed by the nano-antenna layer 12 and forms a plasmon signal on the surface, and the plasmon signal can pass through the The first dielectric layer 14 converts electrical signals to be output through electrode lines. Specifically, the nano-antenna layer 12 may include one or more nano-antennas 121 . That is, each of the pixel structures 10 may include one or more nano-antennas 121 for resonating light of a specific wavelength or polarization to generate plasmon signals, and different pixel structures may resonate for different incident light , the difference may refer to a different wavelength band of incident light or a different resonance direction, the plasmon signal is used to convert into an electrical signal, and then the electrical signal may be output from the electrode line in contact with the pixel structure. It can be understood that if a nano-antenna 121 is set in a pixel structure 10, the nano-antenna 121 can be designed to be larger in size; 121 can be designed to be smaller in size.

In an implementation manner, the nano-antenna 121 may be made of a metal material, for example, the nano-antenna 121 may be any one of metal materials such as gold, silver, copper, and aluminum. It can be understood that the size of the nano-antenna 121 may correspond to a specific optical band, so that the nano-antenna 121 can absorb light of a wavelength within the optical band.

In some possible implementation manners, the first dielectric layer 14 includes a material capable of photoelectric conversion, for example, the first dielectric layer 14 may include a dielectric material with specific parameters. It can be understood that, in some implementation manners, the dielectric material may be silicon, indium gallium arsenic, or the like.

It can be understood that the metal layer 16 can be made of aluminum. Optionally, the metal layer 16 can also be made of noble metals such as gold, silver, platinum, etc., so as to have a better conductive effect. In some embodiments, the metal layer 16 between each pixel structure may not be connected. In some other possible embodiments, the metal layers 16 of a column or a row of pixel structures may be connected together.

In the nano-antenna layer 12, the first electrode lines 122 may be connected to each pixel structure 10 in the same column or row. The second electrode lines 123 may be connected to each pixel structure 10 in the same column or row. Specifically, the first electrode lines 122 may be in contact with the upper surface of the first dielectric layer 12 , and the second electrode lines 123 may be in contact with the lower surface of the first dielectric layer 14 . Based on such a design, the first electrode lines 122 can transmit the electrical signals of the pixel structures in the same row or column to the image processing unit for image processing. The second electrode lines 123 can transmit the electrical signals of the pixel structures in the same row or column to the image processing unit for image processing. This electrical signal is used to obtain an image. Therefore, in the embodiment of the present application, the output signals of each pixel structure can be transmitted through the first electrode lines 122 and the second electrode lines 123 , so as to obtain the output of the image sensor.

Please refer to FIG. 5 , which is a schematic diagram of an image sensor provided by another embodiment of the present application.

It can be understood that the difference between the embodiment of the pixel structure shown in FIG. 5 and the embodiment of the image sensor shown in FIG. 4 is that, as shown in FIG. 5 , the pixel structure 10 may further include a second dielectric layer 18, so The second dielectric layer 18 may be located between the first dielectric layer 14 and the nano-antenna layer 12 . Based on such a design, the embodiment of the present application can enhance the photosensitive intensity, further enhance the light absorption rate of the nano-antenna layer 12 , and reduce the loss of light absorbed by the nano-antenna.

In a specific implementation process, the second dielectric layer 18 may be thinner than the first dielectric layer 14, and the dielectric material of the second dielectric layer 18 may be different from that of the first dielectric layer 14. The dielectric material, that is, the second dielectric layer 18 may not have photosensitive ability, and in a possible implementation manner, the second dielectric layer 18 may be made of a non-photosensitive material. In a possible implementation manner, the material of the second dielectric layer 18 may be silicon dioxide, and the thickness of the second dielectric layer may be 10%-70% of the first dielectric layer 14 . It can be understood that, in other possible implementation manners, each pixel structure may include more than two medium layers, wherein the lowest layer is the first medium layer 14 with a photosensitive function, and the remaining medium layers are non-photosensitive medium layers .

Please refer to FIG. 6 , which is a schematic diagram of an image sensor provided by another embodiment of the present application.

In the embodiments of the present application, each of the pixel structures may be a metal-dielectric-metal structure. It can be understood that the size of the nano-antenna in this embodiment may be positively correlated with the received light wavelength. Thus, the shape and size of the nano-antenna can be set according to the absorbed light wavelength band.

As shown in FIG. 5 , the image sensor in the embodiment of the present application will be described by taking three

pixel structures

10 a , 10 b , and 10 c as examples.

Specifically, the pixel structure 10a may include a nano-antenna layer 12a, a first dielectric layer 14a and a metal layer 16a. The uppermost layer of the pixel structure 10a is the nano-antenna layer 12a, the middle layer of the pixel structure 10a is the first dielectric layer 14a, and the lowermost layer of the pixel structure 10a is the metal layer 16a. It can be understood that the length of the nano-antennas in the nano-antenna layer 12a can be the first length, therefore, the nano-antenna layer 12a can receive incident light with a light wavelength of λ1.

The pixel structure 10b may include a nano-antenna layer 12b, a first dielectric layer 14b and a metal layer 16b. The uppermost layer of the pixel structure 10b is the nano-antenna layer 12b, the middle layer of the pixel structure 10b is the first dielectric layer 14b, and the lowermost layer of the pixel structure 10b is the metal layer 16b. It can be understood that the length of the nano-antenna in the nano-antenna layer 12b can be the second length, therefore, the nano-antenna layer 12b can receive incident light with a light wavelength of λ2.

The pixel structure 10c may include a nano-antenna layer 12c, a first dielectric layer 14c and a metal layer 16c. The uppermost layer of the pixel structure 10c is the nano-antenna layer 12c, the middle layer of the pixel structure 10c is the first dielectric layer 14c, and the lowermost layer of the pixel structure 10c is the metal layer 16c. It can be understood that the length of the nano-antenna in the nano-antenna layer 12a can be the third length, therefore, the nano-antenna layer 12c can receive incident light with a light wavelength of λ3.

For example, if the nano-antenna in the nano-antenna layer 12a has a length of 290nm, the nano-antenna layer 12a can receive 650nm red light. If the nano-antenna in the nano-antenna layer 12b has a length of 250nm, the nano-antenna layer 12b can receive 560nm green light. If the length of the nano-antenna in the nano-antenna layer 12c is 200nm, the nano-antenna layer 12b can receive 450nm blue light.

Based on such a design, the incident light can be strongly coupled by the pixel structure of the embodiment of the present application. Since the nano-antenna can be selective to the light band, light of different colors can enter the corresponding pixel structure 10 for photoelectric conversion.

Furthermore, the metal-dielectric-metal structure in this embodiment can achieve a strong coupling effect, which can fully absorb incident light. At the same time, due to the wavelength-selective concentrating effect of the nano-antenna, the incident light will be absorbed by the corresponding pixel structure of the resonant nano-antenna. Therefore, the photosensitive intensity of the image sensor in the embodiment of the present application is greatly improved. Under the scene, the photosensitive intensity of the image sensor in the embodiment of the present application can be increased by more than 100%.

It is understood that the shape of the nanoantenna can have an effect on the width of the photosensitive band. For example, the bowtie-shaped nanoantenna shown in FIG. 7a can realize a wider photosensitive wavelength band than the stick-shaped nanoantenna shown in FIG. 7b. Therefore, when manufacturing the pixel structure, the nano-antenna can be filled with a transparent material (such as silicon dioxide), so that no air will remain around the nano-antenna, thereby making the structure more stable.

In a possible implementation of the present application, the thickness of the first dielectric layer 14 in each pixel structure may be less than one-fifth of the wavelength of the light to be sensed, thereby achieving a stronger nanocoupling effect, That is, the absorption of light can be further enhanced. In some scenarios, different pixel structures may have the same thickness, that is, the thickness of the first dielectric layer 14 is less than one-fifth of the minimum wavelength of light sensitive to all pixel structures.

In a possible implementation manner of the present application, at least one side length of each pixel structure may be smaller than the maximum wavelength of light sensed by all the pixel structures, thereby realizing the light splitting effect of the pixel structures. Wherein, the side length of the pixel structure may refer to the width or length of the pixel structure. Specifically, at the sub-wavelength size, due to the resonance mechanism, the nanoantenna layer 12 of different wavelength bands can form a plasmon resonance mode, so that the incident light of the corresponding wavelength band can be locally coupled to the corresponding pixel area. Based on such a design, the size of the pixel structure in the embodiments of the present application can be very small. For example, in some embodiments, the length of at least one side of the pixel structure can be smaller than the wavelength of light, thereby realizing super-diffraction and super-resolution Small pixel size.

In a possible implementation manner, the nano-antenna may include a material capable of generating plasmon signals with light, at least one nano-antenna is used to resonate with incident light to generate a plasmon signal, and the plasmon signal is used for Generate electrical signals. Therefore, in the embodiment of the present application, the resonance of the incident light can be realized through the plasmon effect of the smaller nano-antenna and the incident light, and the nano-antenna can absorb the incident light through resonance to improve the utilization of the incident light. efficiency, and on the basis that the nano-antenna absorbs more incident light, it can reduce the crosstalk of incident light in each band.

It can be understood that, in some possible implementation manners, the image sensor 203 may include a plurality of pixel structure sets arranged periodically. The set of pixel structures may include at least two pixel structures. It can be understood that the length of at least one side of the set of pixel structures is less than or equal to half of the minimum wavelength of incident light absorbed by the at least two pixel structures.

As shown in Fig. 8a, the pixel structure set 20 may include linearly arranged

pixel structures

10a, 10b, 10c, and the

pixel structures

10a, 10b, 10c may be used to absorb red light, green light and blue light respectively. Among them, the wavelength of red light is 600 nanometers, the wavelength of green light is 500 nanometers, and the wavelength of blue light is 400 nanometers. For example, the length of the pixel structure 10a may be d1, the length of the pixel structure 10b may be d2, the length of the pixel structure 10c may be d3, and the widths of the

pixel structures

10a, 10b, and 10c are all d4. The length of the

pixel structures

10a, 10b, 10c is d1+d2+d3, because the blue light sensitive to the

pixel structures

10a, 10b, 10c is the minimum wavelength, that is, d1+d2+d3<100nm, and d4<100nm.

In another scenario, as shown in FIG. 8b, the set of pixel structures 20 may include

pixel structures

10a, 10b, 10c, and 10d, and the

pixel structures

10a, 10b, 10c, and 10d may be arranged in a "field" shape, The

pixel structures

10a, 10b, 10c, 10d can be used to absorb red light, green light, green light and blue light respectively. The length of the pixel structure 10a may be d1, the length of the pixel structure 10b may be d2, the length of the pixel structure 10c may be d1, the length of the pixel structure 10d may be d2, and the width of the pixel structure 10a may be d3, The width of the pixel structure 10b may be d4, the width of the pixel structure 10c may be d3, and the width of the pixel structure 10d may be d4, that is, d1+d2<100nm, and d3+d4<100nm.

In some embodiments, a nano-antenna may be disposed on the pixel structure. In some other embodiments, for a pixel structure with a short photosensitive wavelength, since the size of the nano-antenna is also small, multiple nano-antennas may be arranged on the pixel structure.

As shown in FIG. 9 , the image sensor in the embodiment of the present application is described by taking four

pixel structures

10 a , 10 b , 10 c , and 10 d as examples. In this embodiment, the pixel structure 10a may be provided with a nano-antenna 121a. The pixel structure 10b may be provided with a nano-antenna 121b. The pixel structure 10c may be provided with a nano-antenna 121c. The pixel structure 10d may be provided with four nano-antennas 121d, 121e, 121f, 121g. Wherein, the size of the nano-antenna 121b may be the same as that of the nano-antenna 121c. The size of the nano-antenna 121b and the nano-antenna 121c may be smaller than that of the nano-antenna 121a. The dimensions of the nano-antennas 121d, 121e, 121f, and 121g may all be the same. The nanoantennas 121d, 121e, 121f, 121g may be smaller in size than the nanoantenna 121b and the nanoantenna 121c. It can be understood that, in a possible implementation manner, when the pixel structure includes a nano-antenna, the pixel structure has a maximum photosensitive wavelength.

In one embodiment, the connection between the electrode wire and the pixel structure can be achieved by fusing the electrode wire with the nano-antenna. As shown in Figure 10, the first electrode line 122 can be in contact with the upper surface of the first dielectric layer 14, and the first electrode line 122 can be connected to the nano-antennas 121 in the same row or column. 122 may be electrically connected to the nano-antenna 121 . Optionally, the first electrode wire 122 may be electrically connected to the center of the nano-antenna 121 . In a possible implementation manner, the first electrode wire 122 and the nano-antenna 121 may be integrally formed. It can be understood that, in an embodiment, the material of the first electrode wire 122 may be the same material as that of the nano-antenna 121 . In another embodiment, the first electrode line 122 may be a transparent electrode material.

It can be understood that the nano-antenna can have polarization resonance characteristics, and different antennas can sense different polarized light. For example, the polarization direction of the dipole antenna is linear polarization, which is consistent with the extension direction of the antenna, and the polarization direction of the helical antenna is circular polarization. The direction of polarization coincides with the direction of rotation of the antenna. Generally, when the polarization direction of the incident light is consistent with that of the nano-antenna, the absorption of the incident light by the nano-antenna will be improved.

In one embodiment of the present application, when the nano-antenna has a shape with polarization characteristics, the nano-antenna can detect the polarization characteristics of the incident light, that is, the shape of the nano-antenna can be determined according to the polarization characteristics of the incident light that needs to be absorbed. accomplish.

For example, as shown in Figure 11, the nano-antenna can adopt a bow-tie shape antenna, that is, the nano-antenna is a dipole antenna, and the extension directions of the dipole antennas of the two pixel structures are different, and one of the pixel structures (for example, pixel structure 10a) The polarization directions of the nanoantennas of the pixel structure 10a and the nanoantennas of another pixel structure (such as pixel structure 10b) are different, as shown in FIG. In another possible implementation manner, if the nano-antenna is a dipole antenna, the extension directions of the dipole antennas in two adjacent pixel structures are different.

For example, as shown in FIG. 12 , the nano-antenna can be a helical antenna, and the rotation directions of the helical antennas in the two pixel structures are different. For example, the nanoantennas of the pixel structure 10a and the nanoantennas of the pixel structure 10a rotate in different directions. For example, the nanoantennas of the pixel structure 10a rotate clockwise, and the antennas of the pixel structure 10b rotate counterclockwise. In another possible implementation, if the nano-antenna is a helical antenna, the rotation directions of the helical antennas in two adjacent pixel structures are different. As shown in FIG. 13 , the nano-antenna can adopt a square-shaped antenna or a circular-shaped antenna. The pixel structure in this scenario has no polarization characteristics, and thus will not absorb incident light with polarization characteristics.

In a possible scenario, as shown in FIG. 14a , the image sensor 203 in the embodiment of the present application is described by taking four

pixel structures

10a, 10b, 10c, and 10d as examples.

The pixel structure 10a in this scenario can resonate the incident light with transverse polarization, and the pixel structure 10a can absorb the incident light with transverse polarization. The pixel structure 10b can generate resonance to the left obliquely polarized incident light, and the pixel structure 10b can absorb the left obliquely polarized incident light. The pixel structure 10c can generate resonance to the longitudinally polarized incident light, and the pixel structure 10c can absorb the longitudinally polarized incident light. The pixel structure 10d can generate resonance for the incident light with right oblique polarization, and the pixel structure 10d can absorb the incident light with right oblique polarization.

In another possible scenario, as shown in FIG. 14b , the image sensor in the embodiment of the present application is described by taking nine

pixel structures

10a, 10b, 10c, 10d, 10e, 10f, 10g, 10h, and 10i as examples.

In this scene, the pixel structure 10a can absorb red light, the pixel structure 10b can absorb purple light, the pixel structure 10c can absorb blue light, the pixel structure 10d can absorb transversely polarized red light, and the pixel structure 10e can absorb vertically polarized green light, the pixel structure 10f can absorb transversely polarized green light, the pixel structure 10g can absorb transversely polarized orange light, and the pixel structure 10h can absorb longitudinally polarized yellow light, the pixel Structure 10i can absorb longitudinally polarized green light.

In a possible scenario, as shown in FIG. 14c , four

pixel structures

10a, 10b, 10c, and 10d are taken as examples to illustrate the image sensor in the embodiment of the present application.

In this scenario, the pixel structure 10a can absorb green light with transverse polarization, the pixel structure 10b can absorb blue light with left oblique polarization, the pixel structure 10c can absorb red light with right oblique polarization, and the pixel structure 10d can absorb Green light with longitudinal polarization.

By adopting the pixel structure, image sensor and electronic device of the embodiment of the present application, the light-sensing ability of the pixel can be effectively improved through the light-splitting effect of the nano-antenna, and the light-sensing ability of the pixel can be effectively improved, and the crosstalk and wide light-sensing angle can be maintained without introducing angle deviation and crosstalk And problems such as too much difficulty in manufacturing.

In this embodiment, the pixel structure can realize high-efficiency ultra-thin light-sensing, support flexible and curved devices, and improve product competitiveness.

Those of ordinary skill in the art should recognize that the above embodiments are only used to illustrate the present application, rather than to limit the present application. Alterations and variations are within the scope of the claims of this application.

Claims

An image sensor (203), characterized in that it comprises at least two pixel structures (10), the at least two pixel structures (10) are respectively used to absorb two types of incident light with different characteristics, and each of the pixel structures (10) including:

metal layer (16);

A first dielectric layer (14), the first dielectric layer (14) is located on one side of the metal layer (16), and the first dielectric layer (14) includes a photosensitive material;

A nano-antenna layer (12), the nano-antenna layer (12) is located on the side of the first dielectric layer (14) away from the metal layer (16), and the nano-antenna layer (12) includes one or more nano antenna (121);

Wherein, the thickness of the first dielectric layer (14) is less than one-fifth of the minimum wavelength of the incident light absorbed by the pixel structure (10), and at least one side length of the pixel structure (10) is less than the The maximum wavelength of incident light absorbed by the pixel structure (10).
The image sensor (203) according to claim 1, characterized in that,

The two incident lights with different characteristics are incident lights with two different polarizations.
The image sensor (203) according to claim 2, characterized in that,

The one or more nano-antennas (121) are dipole antennas, and the extension directions of the dipole antennas in the at least two pixel structures (10) are different; or

The one or more nano-antennas (121) are helical antennas, and the rotation directions of the helical antennas in the at least two pixel structures (10) are different.
The image sensor (203) according to any one of claims 1-3, characterized in that,

The incident light of the two different characteristics is the incident light of two different wavebands.
The image sensor (203) according to any one of claims 1-4, characterized in that,

The pixel structure (10) also includes a second dielectric layer (18), and the second dielectric layer (18) is located between the nano-antenna layer (12) and the first dielectric layer (14);

The second medium layer (18) includes non-photosensitive material.
The image sensor (203) according to claim 5, characterized in that,

The thickness of the second dielectric layer (18) is smaller than the thickness of the first dielectric layer (14).
The image sensor (203) according to claim 6, characterized in that,

The thickness of the second dielectric layer (18) is 10%-70% of the thickness of the first dielectric layer (14).
The image sensor (203) according to any one of claims 1-7, characterized in that,

The at least two pixel structures (10) are adjacent.
The image sensor (203) according to any one of claims 1-8, characterized in that,

The image sensor (203) also includes one or more first electrode lines (122), and the one or more first electrode lines (122) are in contact with the upper surface of the first dielectric layer (14), The one or more first electrode lines (122) are used to receive electrical signals output by the at least two pixel structures (10), and the electrical signals are used to obtain an image.
The image sensor (203) according to claim 9, characterized in that,

The one or more first electrode lines (122) are in contact with the upper surface of the first dielectric layer (14), and the first electrode lines (122) are electrically connected to the nano-antennas (121) in the same row or column .
The image sensor (203) according to claim 10, characterized in that,

The first electrode line (122) is electrically connected to the center of the nano-antenna (121).
The image sensor (203) according to any one of claims 1-11, characterized in that,

The image sensor (203) also includes one or more second electrode lines (123), and the one or more second electrode lines (123) are in contact with the lower surface of the first dielectric layer (14), The one or more second electrode lines (123) are used to receive electrical signals output by the at least two pixel structures (10), and the electrical signals are used to obtain an image.
The image sensor (203) according to any one of claims 1-12, characterized in that,

The image sensor (203) includes a plurality of pixel structure sets (20) arranged periodically, and the pixel structure set (20) includes the at least two pixel structures (10);

At least one side length of the pixel structure set (20) is less than or equal to half of the minimum wavelength of incident light absorbed by the at least two pixel structures (10).
An electronic device (100), characterized by comprising the image sensor (203) according to any one of claims 1-13.