Multispectral sensor and electronic device

Abstract

The invention discloses a multispectral sensor and electronic equipment. The multispectral sensor provided by the invention comprises a light filtering element and a light sensing element which are arranged in a stacked manner, wherein the light filtering element comprises a plurality of light filtering units, the light sensing element corresponds to the plurality of light filtering units, and the wavelengths of light rays which can pass through the plurality of light filtering units are different; and the light passing through any one of the plurality of light filtering units is incident to the sensing area of the photosensitive element.

Description

Technical Field

[0001] The present application belongs to the field of electronic technology, and specifically relates to a multispectral sensor and electronic equipment. Background Art

[0002] With the rapid development of electronic devices (such as smartphones, etc.), more and more types of sensors are integrated into electronic devices. In order to optimize the photography effect of smartphones in different light environments and improve color reproduction and performance, multispectral sensors that can identify the spectral characteristics of the environment have become an indispensable configuration for smartphones.

[0003] At present, the structure of multi-spectral sensors is to plate filters corresponding to different spectral wavelengths on corresponding photodiodes (PDs), and one filter is used for light sensing. However, there is a problem of high cost of multi-spectral sensors in related technologies. For example, in order to identify the spectral information of multiple spectral channels, the number of filters is large, and the number of corresponding PDs is large, resulting in high cost of multi-spectral sensors. Summary of the invention

[0004] The present application provides a multi-spectral sensor and an electronic device, which at least solve the problem of low sensitivity of the multi-spectral sensor in the related art.

[0005] In a first aspect, the present application provides a multispectral sensor, comprising: a stacked filter element and a photosensitive element; wherein the filter element comprises a plurality of filter units, the photosensitive element corresponds to the plurality of filter units, and the plurality of filter units can pass light of different wavelengths; light passing through any one of the plurality of filter units is incident on a sensing area of ​​the photosensitive element.

[0006] In a second aspect, the present application provides an electronic device, comprising the multispectral sensor provided in the first aspect.

[0007] In an embodiment of the present application, a multispectral sensor includes a filter element and a photosensitive element that are stacked; wherein the filter element includes a plurality of filter units, the photosensitive element corresponds to the plurality of filter units, and the plurality of filter units can pass light of different wavelengths; the light passing through any one of the plurality of filter units is incident on the sensing area of ​​the photosensitive element. Thus, in the multispectral sensor, since the photosensitive element corresponds to the plurality of filter units, the light passing through any one of the plurality of filter units is incident on the sensing area of ​​the photosensitive element, and multiple filter units reuse one photosensitive element. Compared with the related art, the number of photosensitive elements is reduced, and the cost of the multispectral sensor is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which: Figure 1-1 A schematic diagram of a multispectral sensor provided for related technology; Figure 1-2 A partial schematic diagram of a multi-spectral sensor provided for related technology; Figure 2 A schematic diagram of a multispectral sensor provided in an embodiment of the present application; Figure 3 A schematic diagram of another multispectral sensor provided in an embodiment of the present application; Figure 4 A partial schematic diagram of a multi-spectral sensor provided in an embodiment of the present application; Figure 5-1 A schematic diagram of a multi-spectral sensor provided in an embodiment of the present application; Figure 5-2 A schematic diagram of another multispectral sensor provided in an embodiment of the present application; Figure 5-3 A schematic diagram of another multispectral sensor provided in an embodiment of the present application; Figure 5-4 A schematic diagram of another multispectral sensor provided in an embodiment of the present application; Figure 6 A partial schematic diagram of another multi-spectral sensor provided in an embodiment of the present application; Figure 7 A partial schematic diagram of another multi-spectral sensor provided in an embodiment of the present application; Figure 8 A partial schematic diagram of another multi-spectral sensor provided in an embodiment of the present application; Fig. 9 A partial schematic diagram of another multi-spectral sensor provided in an embodiment of the present application; Fig.10 A schematic diagram of an electronic device provided in an embodiment of the present application.

[0009] Description of reference numerals: 10-multi-spectral sensor; 100-filter element; 110-filter unit array; 200-photosensitive layer; 300-light guide element; 400-light transmission control unit; 401-first polarizer; 402-first electrode; 403-switch element; 404-liquid crystal unit; 405-second electrode; 406-second polarizer; 500-light shielding structure; CH-filter unit; CH1-first filter unit; CH2-second filter unit; CH3-filter unit; CH4-filter unit; CH5-filter unit; CH6-filter unit; CH7-filter unit element; CH8-filter unit; CH9-filter unit; CH10-filter unit; CH11-filter unit; CH12-filter unit; CH13-filter unit; CH14-filter unit; CH15-filter unit; CH16-filter unit; PD-sensing element; PD1-sensing element; PD2-sensing element; PD3-sensing element; PD4-sensing element; ADC1-analog-to-digital converter; ADC2-analog-to-digital converter; ADC3-analog-to-digital converter; ADC4-analog-to-digital converter; LC-liquid crystal unit; 1000-electronic device. DETAILED DESCRIPTION

[0010] The embodiments of the present application will be described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and should not be construed as limitations on the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present application.

[0011] The term "first" or "second" in the specification and claims of this application may include one or more of the features explicitly or implicitly. In the description of this application, unless otherwise specified, "plurality" means two or more. In addition, "and / or" in the specification and claims means at least one of the connected objects, and the character " / " generally means that the objects connected before and after are in an "or" relationship.

[0012] In the description of the present application, it should be understood that the terms "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0013] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "connected" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0014] Currently, the spectral channels of multi-spectral sensors are generally 10 to 12 channels, which requires multiple ADCs (Analog to Digital Converters) to sample. The number of ADCs is generally less than the number of spectral channels, so the ADCs need to collect data multiple times in a time-sharing manner. Figure 1-1 As shown in the figure, taking a multi-spectral sensor with 10 spectral channels as an example, the multi-spectral sensor includes 10 PDs (PD0, PD1, ..., PD8, PD9) for photosensitivity, each PD corresponds to a spectral channel, and can identify the spectral information of the 10 spectral channels; the multi-spectral sensor also includes a selector (MUX) and 5 16-bit ADCs (ADC0, ..., ADC4), each of the 5 ADCs samples the spectral information of two PDs in a time-sharing manner, and obtains 10 copies of 16-bit spectral information (DATA 0, ..., DATA 9) corresponding to the 10 spectral channels.

[0015] Currently, multispectral sensors have the following disadvantages: the current number of channels (i.e., 10 channels) is not enough to reconstruct the spectral curve well, and the number of spectral channels for color recognition applications is insufficient. If the number of spectral channels is to be increased, the increase in ADC and PD area will lead to increased costs; a large number of ADCs will lead to an increase in chip area and chip costs; when the PD area is limited, the photosensitive area corresponding to each channel is insufficient, and the amount of light entering is small, which may lead to low sensitivity of the multispectral sensor and spectral sampling distortion.

[0016] For example, Figure 1-2 As shown, currently, the optical structure of a multispectral sensor is generally to plate filters of different spectral channels (i.e., different bands) on the corresponding PDs, and one filter corresponds to one PD for light sensing (for example, filter CH1 corresponds to PD1 for light sensing, ..., filter CH4 corresponds to PD4 for light sensing). When there are many filters, the number of corresponding PDs is large, resulting in a high cost for the multispectral sensor. In addition, due to the limitation of the PD area, the PD area corresponding to a single channel is very small, and the amount of light entering is small, especially in dark environments, the amount of light entering is even smaller, which may lead to low sensitivity of the multispectral sensor and spectral sampling distortion.

[0017] Based on this, the embodiment of the present application provides a multi-spectral sensor, which is not divided into corresponding small sensing elements following the filter unit, but multiple spectral channels corresponding to multiple filter units share one sensing element, and the photosensitive area of ​​a single sensing element can also be expanded. In addition, there are also a light transmission control unit and a light guide element between the filter unit and the sensing element. The light transmission control unit is used to open the corresponding spectral channel in time periods, so that the ambient light is collected by different spectral channels in time periods, and then enters the entire photosensitive area of ​​the sensing element through the light guide element, and is sampled by the ADC (analog-to-digital converter) and converted into a digital signal, which is convenient for spectral information processing.

[0018] In the embodiment of the present application, since multiple filter units share one photosensitive element, compared with the related art, the number of photosensitive elements is reduced, and the number of ADCs can be reduced, thereby reducing the cost of the multi-spectral sensor. Moreover, under the premise of reducing the number of photosensitive elements, the photosensitive area of ​​a single sensing element can be larger. For example, the photosensitive area of ​​a single photosensitive element is the sum of the filter areas of multiple filter units. Compared with the related art, the photosensitive area of ​​a single spectral channel is doubled, thereby improving the sensitivity of the multi-spectral sensor and optimizing the accuracy in a weak light environment.

[0019] The multispectral sensor and electronic device provided in the embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0020] Figure 2 A schematic structural diagram of a multi-spectral sensor is provided for an embodiment of the present application.

[0021] like Figure 2 As shown, the embodiment of the present application provides a multi-spectral sensor 10, which may include: The filter element 100 and the photosensitive element PD are stacked; The filter element 100 includes a plurality of filter units CH, and the photosensitive element PD corresponds to the plurality of filter units CH. The plurality of filter units CH can pass light of different wavelengths. Light passing through any filter unit CH among the plurality of filter units enters the sensing area of ​​the photosensitive element PD.

[0022] The photosensitive element may be a photodiode PD or other types of photosensitive elements. The present application does not impose any specific restrictions on the specific type of the photosensitive element.

[0023] Each of the plurality of filter units CH can pass light of a different wavelength band, and the plurality of filter units have different spectral channels.

[0024] Among them, the multiple filtering units can be four filtering units, or three or five filtering units, etc. The embodiment of the present application does not specifically limit the number of filtering units that share a photosensitive element.

[0025] It should be pointed out that in the related art, one filter unit corresponds to one PD for photosensing. In order to ensure the accuracy of the multi-spectral sensor, the number of filter units is large, and the number of corresponding PDs is large, resulting in a high cost of the multi-spectral sensor. In the multi-spectral sensor provided in the embodiment of the present application, one photosensitive element PD corresponds to multiple filter units CH, and the light passing through any one of the multiple filter units CH is incident on the sensing area of ​​the same photosensitive element PD, so that multiple spectral channels corresponding to multiple filter units share (multiplex) one photosensitive element for photosensing. Compared with the related art, the number of photosensitive elements is reduced, and the cost of the multi-spectral sensor is reduced.

[0026] According to the multispectral sensor provided by the embodiment of the present application, the multispectral sensor includes a filter element and a photosensitive element that are stacked; wherein the filter element includes a plurality of filter units, the photosensitive element corresponds to the plurality of filter units, and the wavelengths of light that can pass through the plurality of filter units are different; the light passing through any one of the plurality of filter units is incident on the sensing area of ​​the photosensitive element. In this way, in the multispectral sensor, since the photosensitive element corresponds to the plurality of filter units, the light passing through any one of the plurality of filter units is incident on the sensing area of ​​the photosensitive element, and multiple filter units reuse one photosensitive element. Compared with the related art, the number of photosensitive elements is reduced, and the cost of the multispectral sensor is reduced.

[0027] In practical applications, such as Figure 3 As shown, a plurality of filter units CH included in a filter element 100 can be arranged in the same layer. In addition, when a multi-spectral sensor includes a plurality of filter elements, the plurality of filter elements can be arranged in the same layer to form a spectral filter layer. Figure 7 As shown, if there are multiple photosensitive elements in the multi-spectral sensor, the multiple photosensitive elements PD1 / PD2 / PD3 / PD4 can also be arranged in the same layer to form a photosensitive layer 200.

[0028] In order to enable the multi-spectral sensor to independently identify the light of each spectral channel, a photosensitive element PD can sense the light passing through different filter units in different time periods, thereby obtaining spectral information of different spectral channels.

[0029] For example, Figure 3 As shown, in a specific example, the filter element 100 includes a plurality of filter units CH1 / CH2 / CH3 / CH4, and the plurality of filter units CH1 / CH2 / CH3 / CH4 correspond to one photosensitive element PD1.

[0030] Among them, the first incident light passing through the first filter unit CH1 among the multiple filter units can be incident to the sensing area of ​​the photosensitive element PD1 in the first time period, and the second incident light passing through the second filter unit CH2 among the multiple filter units can be incident to the sensing area of ​​the photosensitive element PD1 in the second time period, and the first time period and the second time period are staggered with each other.

[0031] Specifically, if Figure 3 As shown, the four spectral channels corresponding to the filter units CH1 / CH2 / CH3 / CH4 share a photosensitive element PD1 for light sensing. In the T1 period, the photosensitive element PD1 can be used to sense the incident light of the filter unit CH1. In the T2 period, the photosensitive element PD1 can be used to sense the incident light of the filter unit CH2. In the T3 period, the photosensitive element PD1 can be used to sense the incident light of the filter unit CH3. In the T4 period, the photosensitive element PD1 can be used to sense the incident light of the filter unit CH4. Among them, the T1 period, the T2 period, the T3 period, and the T4 period are staggered with each other.

[0032] The multi-spectral sensor provided in the embodiment of the present application includes a filter element and a photosensitive element arranged in a stacked manner; wherein the filter element includes a plurality of filter units, and the photosensitive element corresponds to the plurality of filter units, and the wavelengths of light that can be passed through the plurality of filter units are different; the light passing through any one of the plurality of filter units is incident on the sensing area of ​​the photosensitive element, wherein the first incident light passing through the first filter unit among the plurality of filter units can be incident on the sensing area of ​​the photosensitive element in a first time period, and the second incident light passing through the second filter unit among the plurality of filter units can be incident on the sensing area of ​​the photosensitive element in a second time period, and the first time period and the second time period are staggered. In this way, in the multi-spectral sensor, the photosensitive element can sense the incident light of the plurality of filter units passing through different spectral channels in time periods, so that the plurality of filter units can reuse one photosensitive element, and one photosensitive element can sense the light passing through different filter units in different time periods, thereby obtaining the spectral information of the plurality of spectral channels.

[0033] In practical applications, due to the limitations of the total photosensitive area and multiple spectral channels, the photosensitive area corresponding to the filter unit of a single spectral channel is very small, and the amount of light entering is small, especially in dark environments, the amount of light entering is even smaller, which may lead to low sensitivity of the multi-spectral sensor and spectral sampling distortion.

[0034] Based on this, the embodiment of the present application can set the photosensitive area of ​​the photosensitive element to be larger than the filtering area of ​​a single filtering unit, and diffuse the incident light passing through one filtering unit to the entire photosensitive area of ​​the photosensitive element through a light-guiding element, thereby increasing the photosensitive area of ​​the filtering unit corresponding to the spectral channel, thereby improving the sensitivity of the multi-spectral sensor.

[0035] For example, in a specific embodiment, in order to improve the sensitivity of the multi-spectral sensor, Figure 3 As shown, the multi-spectral sensor provided in the embodiment of the present application may further include: a light guide element 300, the light guide element 300 is located between the filter element 100 and the photosensitive element PD1; Among them, the light passing through any one of the multiple filter units (CH1 / CH2 / CH3 / CH4) can be diffused to the entire photosensitive area of ​​the photosensitive element PD1 through the light guiding element 300; the area of ​​the photosensitive area of ​​the photosensitive element PD1 is larger than the filter area of ​​the filter unit CH.

[0036] One light guide element 300 corresponds to one photosensitive element PD1. The light guide range of the light guide element 300 can cover the entire sensing area of ​​the photosensitive element PD1.

[0037] The filter unit may be any one of a plurality of filter units, for example, any one of the filter units CH1 / CH2 / CH3 / CH4, and the present application does not impose any specific limitation on this.

[0038] For example, Figure 5-1 For example, the filter unit may be the first filter unit CH1. For the first filter unit CH1, the light guiding element 300 may diffuse the incident light passing through the first filter unit CH1 to the entire photosensitive area of ​​the photosensitive element PD1; the area of ​​the photosensitive area of ​​the photosensitive element PD1 is larger than the filter area of ​​the first filter unit CH1.

[0039] Among them, after the light-guiding element diffuses the incident light passing through the filter unit to the entire photosensitive area of ​​the photosensitive element, the photosensitive area of ​​the filter unit corresponding to the spectral channel can be the area of ​​the entire photosensitive area of ​​the photosensitive element, that is, the photosensitive area of ​​the filter unit corresponding to the spectral channel is larger than the filter area of ​​the filter unit. Compared with the related art in which the photosensitive area of ​​the filter unit corresponding to the spectral channel is approximately equal to the filter area of ​​the filter unit, the photosensitive area of ​​the filter unit corresponding to the spectral channel is increased, thereby improving the sensitivity of the multi-spectral sensor.

[0040] In this way, the embodiment of the present application increases the photosensitive area of ​​the photosensitive element corresponding to the spectral channel by setting the area of ​​the photosensitive area of ​​the photosensitive element to be larger than the filtering area of ​​the filtering unit, and diffuses the incident light passing through the filtering unit to the entire photosensitive area of ​​the photosensitive element through the light-guiding element, thereby increasing the sensitivity of the multi-spectral sensor.

[0041] In a specific example, in order to expand the area of ​​the photosensitive region of the photosensitive element as much as possible and maximize the sensitivity of the multi-spectral sensor, the area of ​​the photosensitive region of the photosensitive element may be the sum of the filtering areas of multiple filtering units.

[0042] For example, Figure 3 As shown, the area of ​​the photosensitive region of the photosensitive element PD1 is the sum of the filter areas of the four filter units CH1, CH2, CH3, and CH4. Compared with the related art, the photosensitive area of ​​a single filter unit corresponding to the spectral channel is increased four times, and correspondingly, the sensitivity of the multi-spectral sensor is increased four times.

[0043] In this way, since the area of ​​the photosensitive region of the photosensitive element is set to be the sum of the filter areas of multiple filter units, the photosensitive area corresponding to a single spectral channel is multiplied, thereby maximizing the sensitivity of the multi-spectral sensor.

[0044] In practical applications, in order to diffuse the incident light passing through the light filtering unit to the entire photosensitive area of ​​the photosensitive element, the light guide element 300 may be a light diffusion film, and the light diffusion film may cover the photosensitive area of ​​the photosensitive element.

[0045] The light diffusion film has an optical diffusion effect. When the light diffusion film covers the entire photosensitive area of ​​the photosensitive element, the incident light of any filter unit can be diffused to the entire photosensitive area of ​​the photosensitive element.

[0046] Still taking the filter unit CH1 as an example, refer to Figure 5-1 For the filter unit CH1 among the multiple filter units, the light diffusion film can evenly diffuse the incident light passing through the filter unit CH1 to the entire photosensitive area of ​​the photosensitive element PD1, thereby realizing multi-channel spectral sampling, and the photosensitive area corresponding to a single spectral channel is doubled.

[0047] In addition, in practical applications, in a scenario where ambient light is uniformly incident on all filter units in the spectral filter layer, in order to realize time-phased sensing of incident light passing through multiple different spectral channels, the embodiment of the present application may further be provided with a light transmittance control unit, which is used to control the on and off of the incident light, thereby flexibly controlling whether the incident light of the corresponding filter unit is incident on the sensing element.

[0048] For example, in a specific embodiment, Figure 3 As shown, the multi-spectral sensor 10 provided in the embodiment of the present application may further include: a plurality of light transmission control units 400, the plurality of light transmission control units 400 correspond one-to-one to a plurality of light filtering units CH (for example, CH1 / CH2 / CH3 / CH4), and the light transmission control unit 400 is located between the light filtering unit CH and the light guide element 300; The light transmission control unit 400 has a first state and a second state; In the first state, the light transmission control unit 400 blocks the incident light passing through the light filtering unit CH. In the second state, the light transmission control unit 400 allows the incident light passing through the light filtering unit CH to be incident on the light guiding element 300 .

[0049] Among them, one light transmission control unit 400 corresponds to one light filtering unit, and one light transmission control unit 400 can control the on and off of the light passing through the corresponding light filtering unit.

[0050] For example, taking the filter unit as the first filter unit CH1, in the first state, reference Figure 5-2 , a light transmission control unit 400 corresponding to the first filter unit CH1 blocks the incident light passing through the first filter unit CH1; in the second state, the reference Figure 5-1 The light transmission control unit 400 allows the incident light passing through the first filter unit CH1 to be incident on the light guide element 300 and diffused to the photosensitive area of ​​the photosensitive element PD through the light guide element 300 .

[0051] In this way, the light transmission control unit controls whether the incident light of the corresponding filter unit is incident on the sensing element, so that the subsequent sensing element can sense the incident light of multiple filter units with different spectral channels in different time periods.

[0052] In practical applications, the light transmission control unit 400 has the characteristic of controlling the on and off of incident light, and the present application does not limit the specific structure of the light transmission control unit. For example, the present application embodiment can use liquid crystal to control the on and off of incident light.

[0053] For example, refer to Figure 4 The light transmission control unit may include a first polarizer 401, a liquid crystal unit 404, and a second polarizer 406 which are stacked in sequence; a first polarization direction of the first polarizer 401 is perpendicular to a second polarization direction of the second polarizer 406; In the first state, the liquid crystal molecules of the liquid crystal unit 404 face the first direction; the incident light through the filter unit CH becomes polarized light in the first polarization direction after passing through the first polarizer 401, and the polarized light in the first polarization direction is blocked by the second polarizer 406 after passing through the liquid crystal unit 404; Among them, in the second state, the liquid crystal molecules of the liquid crystal unit 404 are twisted from the first direction to the second direction, and the polarized light in the first polarization direction passing through the first polarizer 401 is converted into polarized light in the second polarization direction through the liquid crystal molecules, and the polarized light in the second polarization direction is incident on the light guiding element 300 through the second polarizer 406, and diffused to the photosensitive area of ​​the photosensitive element PD through the light guiding element 300.

[0054] The first polarization direction of the first polarizer 401 is perpendicular to the second polarization direction of the second polarizer 406 , and the incident light can be shut off by two polarization layers with perpendicular polarization directions.

[0055] The liquid crystal unit 404 may be located between the first polarizer 401 and the second polarizer 406 . The liquid crystal molecules of the liquid crystal unit 404 are twisted under the action of the electric field, and polarized light in the first polarization direction may be converted into polarized light in the second polarization direction, thereby achieving conduction of the incident light.

[0056] In addition, the light transmission control unit 400 may further include a first electrode plate 402, a second electrode plate 405 and a switch element 403; the first electrode plate 402 is located between the first polarizer 401 and the liquid crystal unit 404, the second electrode plate 405 is located between the liquid crystal unit 404 and the second polarizer 406, one end of the switch element 403 is coupled to the first electrode plate 402, and the other end of the switch element 403 is coupled to the second electrode plate 405; In the second state, the switch element 403 is turned on, the first electrode plate 402 and the second electrode plate 405 are in a powered state, so that the liquid crystal molecules of the liquid crystal unit 404 are twisted from the first direction to the second direction.

[0057] The first electrode plate 402 and the second electrode plate 405 may be used to encapsulate the liquid crystal molecules of the liquid crystal unit 404 , and to provide an electric field for the liquid crystal unit 404 .

[0058] The switch element 403 may be a thin film transistor, or other types of switches. This embodiment does not limit the specific type of the switch element.

[0059] The switch element 403 is turned on, the first electrode plate 402 and the second electrode plate 405 are in a powered state, and voltage can be applied to the liquid crystal molecules of the liquid crystal unit 404 to twist (rotate and arrange) the liquid crystal molecules from the first direction to the second direction.

[0060] For example, in this embodiment, in the first state, reference Figure 4 In the left part, the switch element 403 is not energized, and the liquid crystal molecules of the liquid crystal unit 404 are oriented in the first direction; the incident light passing through the filter unit is converted into polarized light in the first polarization direction after passing through the first polarizer 401, and the polarized light in the first polarization direction is blocked by the second polarizer 406 after passing through the liquid crystal unit 404, thereby realizing the shutoff of the incident light.

[0061] In this embodiment, in the second state, reference Figure 4 On the right side, the switch element 403 is energized, and the switch element 403 controls the liquid crystal molecules of the liquid crystal unit 404 to twist from the first direction to the second direction. The polarized light in the first polarization direction passing through the first polarizer 401 is converted into the polarized light in the second polarization direction through the liquid crystal molecules. The polarized light in the second polarization direction can pass through the second polarizer 406 and be incident on the photosensitive area of ​​the photosensitive element.

[0062] In this way, the embodiment of the present application sequentially stacks a first polarizer, a switch element, a liquid crystal unit, and a second polarizer in the light transmittance control unit, and realizes the shutoff of the incident light through two polarization layers, and controls the liquid crystal molecules of the liquid crystal unit to twist through the switch element, so that the polarized light in the first polarization direction can be converted into the polarized light in the second polarization direction, thereby realizing the conduction of the incident light, thereby controlling whether the incident light of the corresponding filter unit is incident on the sensing element, so that the subsequent sensing element can realize the time-divided sensing of the incident light of multiple filter units passing through different spectral channels.

[0063] In practical applications, in order to individually control the on and off of the incident light of each filter unit, refer to Figure 5-1 The multi-spectral sensor may include a plurality of liquid crystal units LC, the number of the plurality of liquid crystal units LC is the same as the number of the plurality of filter units, and one liquid crystal unit LC corresponds to one filter unit. In the second state, the incident light through the filter unit passes through the liquid crystal unit corresponding to the filter unit and is incident on the photosensitive area of ​​the photosensitive element.

[0064] For example, taking the first filter unit CH1 as an example, refer to Figure 5-1 The multi-spectral sensor may include four liquid crystal units, one of the four liquid crystal units corresponds to one of the four filter units. In the second state, the incident light through the first filter unit CH1 passes through the first liquid crystal unit corresponding to the first filter unit CH1 and is incident to the photosensitive area of ​​the photosensitive element PD1.

[0065] In this way, the embodiment of the present application can individually control the on and off of the incident light of each filter unit by setting a liquid crystal unit corresponding to each filter unit in the plurality of filter units and individually controlling the liquid crystal molecules in each liquid crystal unit.

[0066] In addition, in order to avoid interference from the spectral channels corresponding to adjacent filter units, such as Figure 3 As shown, the multi-spectral sensor provided in the embodiment of the present application may further include a light shielding structure 500 . The light shielding structure 500 is disposed inside the light guide element 300 and may be located at a boundary between two adjacent liquid crystal units.

[0067] It should be noted that the provision of the light shielding structure 500 can avoid interference from the spectral channels corresponding to the adjacent filter units. Figure 5-1For example, when the liquid crystal molecules of the first liquid crystal unit corresponding to the first filter unit CH1 are controlled to twist, the incident light through the first filter unit CH1 passes through the first liquid crystal unit corresponding to the first filter unit CH1 and enters the photosensitive area of ​​the photosensitive element PD1. Since the light shielding structure 500 is provided at the boundary seam between the first liquid crystal unit corresponding to the first filter unit CH1 and the second liquid crystal unit corresponding to the second filter unit CH2, the incident light through the second filter unit CH2 can be prevented from passing through the boundary of the first liquid crystal unit and entering the photosensitive area of ​​the photosensitive element PD1, thereby avoiding interference from the spectral channel corresponding to the second filter unit, and improving the sampling accuracy of the multi-spectral sensor.

[0068] In addition, the multi-spectral sensor provided in the embodiment of the present application may further include another light shielding structure, which is arranged at the side of a light guide element, but not at the boundary of two adjacent liquid crystal units, for example, Figure 3 As shown, the light shielding structure arranged on the side (the leftmost side or the rightmost side) of the light guide element 300 can avoid interference from ambient light leaking from the side of the filter unit array.

[0069] In practical applications, when multiple spectral channels corresponding to multiple filter units share a sensing element for light sensing, the multiple filter units can be arranged in the spectral filter layer in any arrangement, and the present application does not impose any specific restrictions on the arrangement of the multiple filter units.

[0070] In order to facilitate the multiple spectral channels corresponding to the multiple filter units to share a sensing element for light sensing, the multiple filter units can be arranged adjacent to each other to form a complete filter area, so as to share a sensing element for light sensing. The following is an example of the arrangement of the multiple filter units.

[0071] In a specific embodiment, the plurality of filter units included in the filter element may be located on the same straight line. For example, the spectral filter layer may be provided with a filter unit array, and the plurality of filter units included in the filter element are filter units located on the same straight line in the filter unit array.

[0072] For example, refer to Figure 6 The spectral filter layer may be provided with a filter unit array 110, the filter unit array 110 includes 16 filter units (CH1, CH2, ..., CH16), and the spectral channels of any two filter units are different.

[0073] Of course, in addition to the 4*4 matrix form, the filter unit array 110 can also be set to different matrix forms such as 3*3, 5*5, or 4*5. The present application does not limit the number of filter units in the filter unit array 110 and the specific matrix form.

[0074] In a specific example, the plurality of filter units are filter units located on the same straight line in the filter unit array, and the plurality of filter units may be filter units located on the same row in the filter unit array. Figure 6 and Figure 7 The four spectral channels corresponding to the four filter units CH1, CH2, CH3, and CH4 in the same row share a photosensitive element PD1, the four spectral channels corresponding to the four filter units CH5, CH6, CH7, and CH8 in the same row share a photosensitive element PD2, the four spectral channels corresponding to the four filter units CH9, CH10, CH11, and CH12 in the same row share a photosensitive element PD3, and the four spectral channels corresponding to the four filter units CH13, CH14, CH15, and CH16 in the same row share a photosensitive element PD4.

[0075] In another specific example, the plurality of filter units included in the filter element are filter units located on the same straight line in the filter unit array, and the plurality of filter units included in the filter element are filter units located on the same column in the filter unit array. Figure 6 and Figure 8 The four spectral channels corresponding to the four filter units CH1, CH5, CH9, and CH13 in the same column share a photosensitive element PD1, the four spectral channels corresponding to the four filter units CH2, CH6, CH10, and CH14 in the same column share a photosensitive element PD2, the four spectral channels corresponding to the four filter units CH3, CH7, CH11, and CH15 in the same column share a photosensitive element PD3, and the four spectral channels corresponding to the four filter units CH4, CH8, CH12, and CH16 in the same column share a photosensitive element PD4.

[0076] In this way, when the spectral filter layer is provided with a filter unit array, the multiple filter units can be filter units located on the same straight line in the filter unit array, so that the multiple filter units can form a complete filter area, which is convenient for multiple spectral channels corresponding to the multiple filter units to share one sensing element.

[0077] In addition, the plurality of filter units may be arranged in other ways. For example, the total number of filter units included in the multispectral sensor is A*B, and the A*B filter units constitute a filter unit array, A is the number of rows of the filter unit array, and B is the number of columns of the filter unit array; wherein the number of the plurality of filter units included in the filter element is C*D, C is less than or equal to A, D is less than or equal to B, A, B, C and D are all positive integers, and at least one of A and B is greater than 1.

[0078] Specific reference Figure 6The total number of filter units included in the multi-spectral sensor may be 4*4, and the filter unit array 110 is composed of 4*4 filter units (CH1, CH2, ..., CH16). Each filter unit in the filter unit array 110 can be arranged in the same layer to form a spectral filter layer, wherein the filter element includes a plurality of filter units that share a photosensitive element as 2*2 filter units in the filter unit array 110. Correspondingly, refer to Figure 6 and Fig. 9 The four spectral channels corresponding to the four filter units CH1, CH2, CH5, and CH6 share a photosensitive element PD1, the four spectral channels corresponding to the four filter units CH3, CH4, CH7, and CH8 share a photosensitive element PD2, the four spectral channels corresponding to the four filter units CH9, CH10, CH13, and CH14 share a photosensitive element PD3, and the four spectral channels corresponding to the four filter units CH11, CH12, CH15, and CH16 share a photosensitive element PD4.

[0079] In this way, when the filter unit array of the spectral filter layer is composed of A*B filter units, the multiple filter units can be C*D filter units in the filter unit array, so that the multiple filter units can form a complete filter area, which is convenient for multiple spectral channels corresponding to the multiple filter units to share one sensing element.

[0080] In addition, in order to facilitate spectral information processing, multi-spectral sensors generally use analog-to-digital converters (ADCs) to sample the sensing signals of the photosensitive elements (PDs) and convert them into digital signals. However, in the case of reducing the number of photosensitive elements, the embodiment of the present application can correspondingly reduce the number of ADCs and reduce the cost of the multi-spectral sensor.

[0081] In the embodiment of the present application, the multi-spectral sensor further includes at least one ADC (analog-to-digital converter), and one ADC is connected to one photosensitive element.

[0082] For example, refer to Figure 6 , Figure 7 and Figure 8, the photosensitive layer of the multi-spectral sensor may include four photosensitive elements PD1, PD2, PD3 and PD4. Each photosensitive element may sense the incident light passing through four filter units in different time periods. The multi-spectral sensor also includes four ADCs: ADC1, ADC2, ADC3 and ADC4. Among them, ADC1 is connected to the photosensitive element PD1, and ADC1 is used to sample the sensing signal of the photosensitive element PD1; wherein ADC2 is connected to the photosensitive element PD2, and ADC2 is used to sample the sensing signal of the photosensitive element PD2; wherein ADC3 is connected to the photosensitive element PD3, and ADC3 is used to sample the sensing signal of the photosensitive element PD3; wherein ADC4 is connected to the photosensitive element PD4, and ADC4 is used to sample the sensing signal of the photosensitive element PD4.

[0083] In this way, since the number of photosensitive elements is reduced, the number of ADCs can be reduced accordingly, the chip area for ADC layout can be reduced, and the cost of the multi-spectral sensor can be reduced.

[0084] In practical applications, the embodiments of the present application can increase the photosensitive area of ​​each spectral channel during sampling by time-division multiplexing the photosensitive area of ​​the photosensitive elements in a limited area, thereby improving the sensitivity of the multi-spectral sensor and optimizing the accuracy in low-light environments.

[0085] by Figure 6 and Figure 7 For example, filter units CH1 / CH2 / CH3 / CH4 share the photosensitive element PD1, filter units CH5 / CH6 / CH7 / CH8 share the photosensitive element PD2, filter units CH9 / CH10 / CH11 / CH12 share the photosensitive element PD3, and filter units CH13 / CH14 / CH15 / CH16 share the photosensitive element PD4.

[0086] During actual sampling, the liquid crystal circuit under the filter unit is opened column by column in a time-sharing manner, so that each column of filter units is incident on the PD respectively.

[0087] In the first period (T1 period), the liquid crystal circuit of the first column is turned on, and the incident light of the corresponding bands of the filter units CH1 / CH5 / CH9 / CH13 is respectively irradiated on the four PDs PD1 / PD2 / PD3 / PD4, while the incident light of other channels (CH5...CH16) is closed, and the light cannot penetrate the liquid crystal. At this time, the light of the CH1 / CH2 / CH3 / CH4 bands is respectively sensed by PD1 / PD2 / PD3 / PD4 and then sampled by ADC.

[0088] Similarly, in the second time period (T2 period), the liquid crystal circuit of the second column is turned on, and the incident light of the corresponding band of the filter unit CH2 / CH6 / CH10 / CH14 is respectively sensed by PD1 / PD2 / PD3 / PD4 and then sampled by ADC.

[0089] Similarly, in the third time period (T3 period), the liquid crystal circuit of the third column is turned on, and the incident light of the corresponding band of the filter units CH3 / CH7 / CH11 / CH15 is respectively sensed by PD1 / PD2 / PD3 / PD4 and then sampled by ADC.

[0090] Similarly, in the fourth time period (T4 period), the liquid crystal circuit of the fourth column is turned on, and the incident light of the corresponding bands of the filter units CH4 / CH8 / CH12 / CH16 is respectively sensed by PD1 / PD2 / PD3 / PD4 and then sampled by the ADC.

[0091] The following takes the four filter units CH1 / CH2 / CH3 / CH4 in the first row sharing the photosensitive element PD1 as an example to illustrate the operation process of the time periods T1, T2, T3, and T4.

[0092] In the T1 period, refer to Figure 5-1 , turn on the liquid crystal circuit in the corresponding area of ​​the filter unit CH1, and the incident light in the corresponding band of the filter unit CH1 is irradiated onto PD1, while the liquid crystal circuits corresponding to the incident light of other channels (CH2, CH3, CH4) are turned off, and the light cannot penetrate the liquid crystal. At this time, the incident light in the corresponding band of CH1 is sensed by PD1 and then sampled by ADC1.

[0093] In the T2 period, refer to Figure 5-2 , turn on the liquid crystal circuit in the corresponding area of ​​the filter unit CH2, and the incident light in the corresponding band of the filter unit CH2 is irradiated onto PD1, while the liquid crystal circuits corresponding to the incident light of other channels (CH1, CH3, CH4) are turned off, and the light cannot penetrate the liquid crystal. At this time, the incident light in the corresponding band of CH2 is sensed by PD1 and then sampled by ADC1.

[0094] In the T3 period, refer to Figure 5-3 , turn on the liquid crystal circuit in the area corresponding to the filter unit CH3, and the incident light in the corresponding band of the filter unit CH3 is irradiated onto PD1, while the liquid crystal circuits corresponding to the incident light of other channels (CH1, CH2, CH4) are turned off, and the light cannot penetrate the liquid crystal. At this time, the incident light in the corresponding band of CH3 is sensed by PD1 and then sampled by ADC1.

[0095] In the T4 period, refer to Figure 5-4, turn on the liquid crystal circuit of the corresponding area of ​​the filter unit CH4, and the incident light of the corresponding band of the filter unit CH4 is irradiated on PD1, while the liquid crystal circuits corresponding to the incident light of other channels (CH1, CH2, CH3) are turned off, and the light cannot penetrate the liquid crystal. At this time, the incident light of the corresponding band of CH4 is sensed by PD1 and then sampled by ADC1.

[0096] In this way, the spectral information of all spectral channels is sampled in different time periods and the real spectral details are restored after processing.

[0097] The multi-spectral sensor provided in the embodiment of the present application saves the number of photosensitive elements and the number of ADCs and reduces costs by time-division multiplexing the photosensitive area of ​​a limited region.

[0098] In addition, the photosensitive area when sampling a single spectral channel is increased, the sensitivity of the multispectral sensor is improved, and the accuracy in weak light is optimized.

[0099] For example, if the number of channels and sensitivity are kept the same, compared with the 16-channel multispectral sensor in the prior art, the present application Figure 6 and Figure 7 The 16-channel multi-spectral sensor provided by the illustrated embodiment can reduce the total photosensitive area to 1 / 4 of the original area, thereby saving the number of photosensitive elements and the number of ADCs and reducing costs.

[0100] For another example, if the total photosensitive area is kept the same, compared with the 16-channel multi-spectral sensor in the prior art, the present application Figure 6 and Figure 7 The 16-channel multi-spectral sensor provided in the illustrated embodiment has a photosensitive area that is increased by 4 times when a single spectral channel is sampled, and the sensitivity of the multi-spectral sensor is increased by 4 times.

[0101] For another example, if the total photosensitive area and sensitivity are kept the same, compared with the 16-channel multi-spectral sensor in the prior art, the present application Figure 6 and Figure 7 The 16-channel multi-spectral sensor provided in the illustrated embodiment can increase the number of channels by 4 times and the sampling accuracy by 4 times.

[0102] Based on the same concept as the multi-spectral sensor provided in any of the above embodiments, an embodiment of the present application further provides an electronic device.

[0103] like Fig.10 As shown, an embodiment of the present application provides an electronic device 1000 including a multi-spectral sensor 10 .

[0104] It should be pointed out that the electronic device provided in the embodiments of the present application includes the multispectral sensor provided in any of the above embodiments and can realize all the functions of the multispectral sensor. To avoid repetition, it will not be described here.

[0105] In the embodiment of the present application, the electronic device may be a terminal or other device other than a terminal. For example, the electronic device may be a smart watch, a mobile phone, a tablet computer, a laptop computer, a PDA, a vehicle-mounted electronic device, a mobile Internet device (MID), an augmented reality (AR) / virtual reality (VR) device, a robot, a wearable device, an ultra-mobile personal computer (UMPC), a netbook or a personal digital assistant (PDA), etc. It may also be a server, a network attached storage (NAS), a personal computer (PC), etc., which is not specifically limited in the embodiment of the present application.

[0106] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0107] Although the embodiments of the present application have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present application, and that the scope of the present application is defined by the claims and their equivalents.

Claims

1. A multispectral sensor, characterized in that: include: A filter element and a photosensitive element are stacked; Among them, the filter element includes multiple filter units, the photosensitive element corresponds to the multiple filter units, and the multiple filter units can pass light with different wavelengths; the light passing through any one of the multiple filter units is incident on the sensing area of ​​the photosensitive element.

2. The multispectral sensor according to claim 1, characterized in that: The first incident light passing through the first filter unit among the multiple filter units is incident to the sensing area of ​​the photosensitive element in the first time period, and the second incident light passing through the second filter unit among the multiple filter units is incident to the sensing area of ​​the photosensitive element in the second time period, and the first time period and the second time period are staggered with each other.

3. The multispectral sensor according to claim 1 or 2, characterized in that: The multi-spectral sensor further comprises a light-guiding element, wherein the light-guiding element is located between the light-filtering element and the light-sensing element; The light passing through any one of the plurality of filter units is diffused to the entire photosensitive area of ​​the photosensitive element via the light guide element; the area of ​​the photosensitive area of ​​the photosensitive element is larger than the filter area of ​​the filter unit.

4. The multispectral sensor according to claim 3, characterized in that: The area of ​​the photosensitive region of the photosensitive element is the sum of the filtering areas of the plurality of filtering units.

5. The multispectral sensor according to claim 3, characterized in that: The light guide element is a light diffusion film, and the light diffusion film covers the light sensing area of ​​the light sensing element.

6. The multispectral sensor according to claim 3, characterized in that: The multi-spectral sensor further comprises a plurality of light transmission control units, the plurality of light transmission control units correspond to the plurality of light filtering units one by one, and the light transmission control units are located between the light filtering units and the light guiding element; The light transmission control unit has a first state and a second state; in the first state, the light transmission control unit blocks the incident light passing through the filter unit, and in the second state, the incident light passing through the filter unit penetrates the light transmission control unit and is incident on the light guiding element.

7. The multispectral sensor according to claim 6, characterized in that: The light transmission control unit comprises a first polarizer, a liquid crystal unit and a second polarizer which are stacked in sequence; a first polarization direction of the first polarizer is perpendicular to a second polarization direction of the second polarizer; Wherein, in the first state, the liquid crystal molecules of the liquid crystal unit face the first direction; the incident light passing through the filter unit becomes polarized light in the first polarization direction after passing through the first polarizer, and the polarized light in the first polarization direction is blocked by the second polarizer after passing through the liquid crystal unit; In which, in the second state, the liquid crystal molecules of the liquid crystal unit are twisted from the first direction to the second direction, and the polarized light in the first polarization direction passing through the first polarizer is converted into polarized light in the second polarization direction through the liquid crystal molecules, and the polarized light in the second polarization direction is incident on the light guide element through the second polarizer, and diffused to the photosensitive area of ​​the photosensitive element via the light guide element.

8. The multispectral sensor according to claim 7, characterized in that: The light transmission control unit further includes a first electrode plate, a second electrode plate and a switch element; the first electrode plate is located between the first polarizer and the liquid crystal unit, the second electrode plate is located between the liquid crystal unit and the second polarizer, one end of the switch element is coupled to the first electrode plate, and the other end of the switch element is coupled to the second electrode plate; In the second state, the switch element is turned on, the first electrode plate and the second electrode plate are in a powered state, so that the liquid crystal molecules of the liquid crystal unit are twisted from the first direction to the second direction.

9. The multispectral sensor according to claim 7, characterized in that: The multi-spectral sensor further comprises a light shielding structure, which is arranged inside the light guide element and located at the boundary between two adjacent liquid crystal units.

10. The multispectral sensor according to any one of claims 1 to 9, characterized in that: The multi-spectral sensor further includes at least one analog-to-digital converter ADC, and one of the ADCs is connected to one of the photosensitive elements.

11. An electronic device, characterized in that: Comprising the multispectral sensor as described in any one of claims 1-10.

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