Optical sensor, method of producing an optical sensor, electronic device and method of operating an electronic device

Abstract

An optical sensor (1) comprising a plurality of detection channels (2) is specified, wherein - the detection channels (2) each comprise a photodetector (3) and a filter (4) to define a spectral sensitivity of the respective detection channel (2); - the detection channels (2) comprise a first set of detection channels (21), the first set of detection channels (21) comprising a first detection channel (21B) with a wavelength of maximum sensitivity in a blue spectral range, a second detection channel (21G) with a wavelength of maximum sensitivity in a green spectral range, and a third detection channel (21R) with a wavelength of maximum sensitivity in a red spectral range; - the detection channels (2) comprise a second set of detection channels (22), wherein wavelengths of maximum sensitivity of the detection channels of the second set (22) are arranged between wavelengths of maximum sensitivity of the detection channels of the first set; and - the spectral sensitivities of the detection channels (2) are configured such that a best match fitting curve (7Z, 7Y, 7X) for each of the three CIE1931 color matching functions (8Z, 8Y, 8X) is obtainable from a linear combination of the spectral sensitivities of the detection channels (2). Further, a method of producing an optical sensor, an electronic device, and a method of operating an electronic device are specified.

Description

[0001] Description

[0002] OPTICAL SENSOR, METHOD OF PRODUCING AN OPTICAL SENSOR, ELECTRONIC DEVICE AND METHOD OF OPERATING AN ELECTRONIC

[0003] DEVICE

[0004] The present application refers to an optical sensor, to a method of producing an optical sensor, to an electronic device , and to a method of operating an electronic device .

[0005] For smart display control the white point of the display may be adj usted to the ambient light condition . However, color and spectral ambient light sensing behind a display is af fected by the transmittance of the display and signi ficant back scattered light from the display .

[0006] It is an obj ect to provide a way to improve the capabilities of ambient light sensing .

[0007] This obj ect is achieved by an optical sensor, a method of producing an optical sensor, an electronic device , and a method of operating an electronic device according to the independent claims . Further configurations and developments are the subj ect of the dependent claims .

[0008] An optical sensor comprising a plurality of detection channels is speci fied .

[0009] According to at least one embodiment of the optical sensor, each detection channel comprises a photodetector and a filter to define a spectral sensitivity of the respective detection channel . For example , the photodetector is a photodiode comprising a photosensitive region based on a semiconductor material such as silicon . In particular, all photodetectors of the detection channels may be based on the same semiconductor material .

[0010] The photodetectors of the detection channels may be integrated in a common sensor chip . Alternatively, the photodetectors may be separate devices .

[0011] An individual detection channel may comprise one photodetector or more than one photodetector .

[0012] For example , the filter is configured as a band pass filter .

[0013] For example , the filter comprises an interference filter, an absorption filter, a plasmonic filter or a combination thereof .

[0014] An interference filter may be formed by a dielectric layer stack wherein each layer of the stack may be adapted with respect to its layer thickness and its refractive index such that optical interference ef fects at the interfaces between the layers result in the intended transmission spectrum .

[0015] In an absorption filter, electromagnetic radiation with wavelengths outside the intended transmission spectrum of the filter can be absorbed . A plasmonic filter may be formed by structured metal layers that exhibit plasmonic properties .

[0016] According to at least one embodiment of the optical sensor, the detection channels comprise a first set of detection channels . In particular, the first set of detection channels comprises a first detection channel with a wavelength of maximum sensitivity in a blue spectral range , a second detection channel with a wavelength of maximum sensitivity in a green spectral range , and a third detection channel with a wavelength of maximum sensitivity in a red spectral range .

[0017] For example , the wavelength of maximum sensitivity of the first detection channel is at least 420 nm or at least 430 nm or at least 450 nm and / or at most 480 nm or at most 470 nm .

[0018] For example , the wavelength of maximum sensitivity of the second detection channel is at least 500 nm or at least 510 nm and / or at most 550 nm or at most 540 nm or at most 530 nm .

[0019] For example , a wavelength of maximum sensitivity of the third detection channel is at least 600 nm or at least 610 nm and / or at most 700 nm or at most 680 nm or at most 650 nm .

[0020] In particular, the wavelengths of maximum sensitivity of the detection channels of the first set may be selected such that the spectral sensitivity of each detection channel overlaps with one of the peak emission wavelengths of emitters of an RGB display .

[0021] According to at least one embodiment of the optical sensor, the detection channels comprise a second set of detection channels , wherein wavelengths of maximum sensitivity of the detection channels of the second set are arranged between wavelengths of maximum sensitivity of the detection channels of the first set . In other words , the wavelengths of maximum sensitivity of the detection channels of the second set are larger than the wavelength of maximum sensitivity of the first detection channel and smaller than the wavelength of maximum sensitivity of the third detection channel . For example , the wavelength of maximum sensitivity of each detection channel of the second set di f fers from all wavelengths of maximum sensitivity of the first set by at least 10 nm or at least 20 nm .

[0022] According to at least one embodiment of the optical sensor, the spectral sensitivities of the detection channels are configured such that a best match fitting curve for each of the three CIE1931 ( International Commission on I llumination, CIE : Commission Internationale de 1 ' eclairage ) color matching functions is obtainable from a linear combination of the spectral sensitivities of the detection channels .

[0023] The color matching function x( ) comprises two maxima in the visible spectral range . The y( ) color matching function comprises a maximum in the green spectral range . The z( ) color matching function comprises one peak in the blue spectral range . Collectively, these three color matching functions describe the CIE standard observer .

[0024] These color matching functions represent the ideal spectral sensitivity curves of three linear light detectors providing the tristimulus values X, Y and Z in the CIE XYZ color space , wherein Y is the luminance . For each color sensed by a human observer three tristimulus values can be determined .

[0025] Each of these color matching functions can be obtained or at least approximated by adding the spectral sensitivities of at least two detection channels , wherein the spectral sensitivities of the detection channels used are multiplied with a scaling factor prior to the addition . Ideally, the best match fitting curve corresponds exactly to the respective color matching function . However, this is not necessarily required in order to obtain the tristimulus values with suf ficient accuracy .

[0026] For example , an area below a color matching function overlaps to at least 80% or at least 90% with an area below the respective best match fitting function and / or vice versa .

[0027] For example , a full width at hal f maximum of the best match fitting curve di f fers from the full width at hal f maximum of the respective color matching function by at most 20 % or at mo st 10 % .

[0028] In at least one embodiment of the optical sensor, the optical sensor comprises a plurality of detection channels , wherein the detection channels each comprise a photodetector and a filter to define a spectral sensitivity of the respective detection channel . The detection channels comprise a first set of detection channels , the first set of detection channels comprising a first detection channel with a wavelength of maximum sensitivity in a blue spectral range , a second detection channel with a wavelength of maximum sensitivity in a green spectral range , and a third detection channel with a wavelength of maximum sensitivity in a red spectral range . The detection channels further comprise a second set of detection channels , wherein wavelengths of maximum sensitivity of the detection channels of the second set are arranged between wavelengths of maximum sensitivity of the detection channels of the first set . The spectral sensitivities of the detection channels are configured such that a best match fitting curve for each of the three CIE1931 color matching functions is obtainable from a linear combination of the spectral sensitivities of the detection channels . When operating the optical sensor behind a display, the signals from the first set of detection channels may be used to compensate for unwanted back scattered light from the display . Further, linear combinations of the signals of the detection channels can be used to determine the tristimulus values with a high accuracy . In other words , the tristimulus values X, Y and Z of the light detected by the optical sensor during operation can be obtained in each case by multiplying the signals from at least two associated detection channels with a scaling factor and adding these scaled signals .

[0029] In particular, spectral information on the ambient light can even be obtained i f the signal from the ambient light is small compared to the back scattered light of the display .

[0030] Furthermore , the optical sensor does not have to be operated during a short dark period of the display between the frame refresh . Thus , the optical sensor may also be used for advanced displays that exhibit only a very short or even no dark period .

[0031] According to at least one embodiment of the optical sensor, the second set of detection channels comprises exactly one detection channel with a wavelength of maximum sensitivity between the wavelength of maximum sensitivity of the first detection channel and the wavelength of maximum sensitivity of the second detection channel . For example , the wavelength of maximum sensitivity of the detection channel of the second set corresponds to the average of the wavelength of maximum sensitivity of the first detection channel and the wavelength of maximum sensitivity of the second detection channel with a tolerance of at most 10 nm or at most 5 nm . According to at least one embodiment of the optical sensor, the second set of detection channels comprises exactly two detection channels with a wavelength of maximum sensitivity between the wavelength of maximum sensitivity of the second detection channel and the wavelength of maximum sensitivity of the third detection channel . For example , the wavelength of maximum sensitivity of one of the detection channels of the second set is smaller than an average of the wavelengths of maximum sensitivity of the second detection channel and the third detection channel , and the wavelength of maximum sensitivity of the other one of the two detection channels of the second set is larger than the average of the wavelength of maximum sensitivity of the second detection channel and the wavelength of maximum sensitivity of the third detection channel .

[0032] According to at least one embodiment of the optical sensor, the wavelengths of maximum sensitivity of the detection channels of the first set and of the second set taken together are arranged in a spectrally equidistant manner with a tolerance of at most 10 % . In other words , the detection channels of the first set and the second set taken together have substantially the same spectral distance from one another .

[0033] According to at least one embodiment of the optical sensor, the detection channels comprise a third set of detection channels , wherein a wavelength of maximum sensitivity of at least one of the detection channels of the third set is smaller than the wavelength of maximum sensitivity of the first detection channel , and / or a wavelength of maximum sensitivity of at least one of the detection channels of the third set is larger than a wavelength of maximum sensitivity of the third detection channel .

[0034] In other words , the wavelengths of maximum sensitivity of all channels of the third set are arranged outside of a spectral range extending from the wavelength of maximum sensitivity of the first detection channel to the wavelength of maximum sensitivity of the third detection channel . Thus , the detection channels of the third set may provide spectral information near the short wavelength edge of the visible spectral range and / or near the long wavelength edge of the visible spectral range .

[0035] According to at least one embodiment of the optical sensor, a full width at hal f maximum of a spectral sensitivity of at least one of the detection channels is at least 90 % and at most 150 % of an average spectral distance between two spectrally adj acent detection channels .

[0036] It hast turned out that spectral sensitivity distributions having a comparably large full width at hal f maximum facilitate the reconstruction of the color matching functions by appropriate linear combinations of the signals . On the other hand, a too large full width at hal f maximum results in a too strong spectral overlap between spectrally adj acent detection channels .

[0037] According to at least one embodiment of the optical sensor, the wavelengths of maximum sensitivity of the detection channels of the first set , the second set and the third set taken together are arranged in a spectrally equidistant manner with a tolerance of at most 10 % . In particular, the entire visible spectral range or at least the relevant part thereof may be covered by the spectrally equidistant detection channels . This helps to obtain reliable spectral information and / or the brightness of the ambient light perceived by the human eye .

[0038] Further, a method of producing an optical sensor is speci fied, wherein the optical sensor is in particular configured as an ambient light sensor behind a display .

[0039] In at least one embodiment of the method, the method includes the steps of providing spectral information on emitters of the display and producing a plurality of detection channels , wherein the detection channels each comprise a photodetector and a filter . The filters of a first set of detection channels are configured such that a spectral sensitivity of each detection channel of the first set of detection channels overlaps with an emission spectrum of an associated emitter . The filters of a second set of detection channels are configured such that wavelengths of maximum sensitivity of the detection channels of the second set are arranged between wavelengths of maximum sensitivity of the detection channels of the first set . The filters of the detection channels are configured such that a best match fitting curve for each of the three CIE1931 color matching functions is obtainable from a linear combination of the spectral sensitivities of the detection channels .

[0040] Thus , the spectral sensitivities of the first set of detection channels can be adapted to the respective spectral characteristics of the emitters of the display . Consequently, the optical sensor can be customi zed for di f ferent types of displays during production of the optical sensor . Further, the shape and the width of the spectral sensitivity of each detection channel may be optimi zed to obtain a best match to the color matching functions by a linear combination of appropriate detection channels .

[0041] The method is particularly suited to produce an optical sensor as described above . Thus , features described in connection with the optical sensor also apply for the method and vice versa .

[0042] Further, an electronic device comprising an optical sensor is speci fied . The optical sensor may comprise one or more of the features described above .

[0043] In at least one embodiment of the electronic device , the electronic device comprises an optical sensor and a display with a plurality of pixels , where the pixels comprise emitters with emission spectra in the blue , green and red spectral ranges , wherein the spectral sensitivities of the detection channels of the first set of detection channels overlap with the respective emission spectra of the emitters . For example , the wavelengths of maximum sensitivity of the detection channels of the first set of detection channels di f fer from the peak emission wavelength of the associated emitter by at most 20 nm or at most 10 nm .

[0044] For example , the emitters are light emitting diodes . For example , the emitters are based on organic material . Organic light emitting diodes are also referred to as OLEDs . Alternatively, the emitters may be based on an inorganic semiconductor material such as a I I I-V-compound semiconductor material . According to at least one embodiment of the electronic device , the optical sensor is arranged behind the display in a top view onto the display . In other words , ambient light passes through the display on its way to the optical sensor .

[0045] According to at least one embodiment of the electronic device , the optical sensor is configured to analyze an ambient light during operation of the display . For example , the ambient light is analyzed with respect to its correlated color temperature and / or irradiance .

[0046] According to at least one embodiment of the electronic device , the optical sensor is configured to compensate for back scattered light from the emitters by means of the first set of detection channels .

[0047] According to at least one embodiment of the electronic device , the electronic device is configured to adapt a white point of the display based on a signal from the optical sensor . For example , the white point of the display may be shi fted towards warm white i f the ambient light is warm white .

[0048] The electronic device may be any device comprising a display . For example , the electronic device may be a mobile or handheld device such as a smartphone , a tablet or a notebook, or a wearable device such as a smartwatch, or a stationary device such as a computer monitor or a TV set .

[0049] Further, a method of operating an electronic device is speci fied, wherein the electronic device may be configured as described above . According to at least one embodiment of the method, an ambient light is analyzed based on a signal of at least some of the detection channels .

[0050] For example , the number of detection channels used for the analysis may depend on the contribution of the back scattered light to the overall signal detected by all detection channels . I f , for example , the contribution of back scattered light is small compared to the ambient light , most of the detection channels or all of the detection channels may be used to analyze the ambient light .

[0051] I f the contribution of the back scattered light is comparably large , the back scattered light may be compensated for by means of the first set of detection channels .

[0052] According to at least one embodiment of the method, at least some of the emitters of the display are operated during the detection of the ambient light . In particular, the detection of the ambient light does not require a dark period of the display .

[0053] According to at least one embodiment of the method, signals of the first set of detection channels are used to compensate for back scattered light from the emitters . This helps to improve the reliability of the detection of the ambient light .

[0054] According to at least one embodiment of the method, a spectral reconstruction of the ambient light is performed . For example , a spectral reconstruction of the ambient light may be used to identi fy the light sources surrounding the electronic device . Based on this information, the display properties such as the white point may be adapted to increase the users ' comfort .

[0055] For example , an ambient light calculation may be performed . For example , a 3 x 3 matrix using a compensated second set of detection channels may be used to derive a signal that is similar to the perception of the human eye . Generally, a compensated spectral reconstruction may be performed using an m x n matrix wherein m is the number of detection channels used and n is the number of spectral components to be considered .

[0056] By means of the described sets of detection channels a high reliability of ambient light sensing may be obtained . In particular, the reliability is increased compared to an approach where only spectral ranges between the emission spectra of the emitters of the display are used because these spectral ranges alone only provide limited information on the spectrum of the ambient light .

[0057] Features described above in connection with at least one embodiment of the optical sensor or the electronic device or one of the methods can be combined with other features described in connection with at least one embodiment of the optical sensor or the electronic device or one of the methods unless they are contradictory .

[0058] Further features and expediencies will become apparent from the subsequent description of the exemplary embodiments in connection with the Figures .

[0059] In the exemplary embodiments and Figures similar or similarly acting constituent parts are labeled with the same reference signs . Only the di f ferences with respect to the individual exemplary embodiments are described . Unless speci fied otherwise , the description of a part or feature in one exemplary embodiment applies to a corresponding part or feature in another exemplary embodiment as well .

[0060] In the Figures :

[0061] Figures 1A and B show an exemplary embodiment of an optical sensor in a cross-sectional view ( Figure 1A) and in a top view ( Figure IB ) ;

[0062] Figure 1C shows an exemplary embodiment of a detection channel of the optical sensor ;

[0063] Figure ID shows an exemplary embodiment of an electronic device in a cross-sectional view;

[0064] Figure IE shows spectral sensitivities S (A / W) according to an exemplary embodiment of an optical sensor compared to spectral intensities I (W) of emitters of a display, to a spectral sensitivity of a silicon photodiode without a filter, and to examples of ambient light spectra ;

[0065] Figure I F shows spectral sensitivities S (A / W) of detection channels according to an exemplary embodiment of an optical sensor 1 , the three CIE1931 color matching functions ( 8 Z , 8Y, 8X ) and associated best match fitting curves obtained from linear combinations of the spectral sensitivities of the detection channels shown;

[0066] Figure 2A shows spectral sensitivities S (A / W) according to an exemplary embodiment of an optical sensor compared to emission spectra of emitters of a display, to a sensitivity of a silicon photodiode without a filter, and examples of ambient light spectra ;

[0067] Figure 2B shows spectral sensitivities of detection channels according to an exemplary embodiment of an optical sensor, the three CIE1931 color matching functions and associated best match fitting curves obtained from linear combinations of the spectral sensitivities of the detection channels shown;

[0068] Figure 3 shows spectral sensitivities S according to an exemplary embodiment of an optical sensor compared to emission spectra of emitters of a display, to a sensitivity of a silicon photodiode without a filter, and examples of ambient light spectra .

[0069] Figure 4 shows an exemplary embodiment of a method of producing an optical sensor ; and

[0070] Figure 5 shows an exemplary embodiment of a method of operating an electronic device .

[0071] The elements illustrated in the figures and their si ze relationships among one another are not necessarily true to scale . Rather, individual elements or layer thicknesses may be represented with an exaggerated si ze for the sake of better representability and / or for the sake of better understanding .

[0072] An exemplary embodiment of an optical sensor 1 and an electronic device 10 is illustrated in Figures 1A to I F . The optical sensor 1 comprises a plurality of detection channels 2 .

[0073] As shown in Figure 1C the detection channels 2 each comprise a photodetector 3 and a filter 4 . By means of the filter 4 the spectral sensitivity of the respective detection channel 2 can be defined . Each filter 4 may comprise or consist of an interference filter, an absorption filter, a plasmonic filter or a combination thereof .

[0074] As illustrated in Figures 1A and IB the optical sensor 1 may comprise a sensor chip 11 with a photosensitive area 15 . The optical sensor 1 may comprise an optional sensor package 12 with an aperture 13 . A filter structure 40 comprising a plurality of filters 4 is arranged on top of the photosensitive area 15 to define the respective spectral sensitivity of the detection channels 2 .

[0075] Figure IB exemplarily illustrates 16 filters 4 in a 4 x 4 array . However, the number of filters 4 and associated photodetectors 3 can be varied in wide limits . Each detection channel 2 may comprise one or more photodetectors 3 with associated filters 4 .

[0076] As illustrated in Figure ID the optical sensor 1 is particularly suited as an optical sensor 1 configured to be placed below a display 5 of an electronic device 10 . For example , the electronic device 10 is a mobile electronic device or a stationary electronic device .

[0077] The display 5 comprises a plurality of pixels 51 , wherein each pixel 51 comprises an emitter 51B configured to emit radiation in the blue spectral range , and emitter 51G configured to emit radiation in the green spectral range , and an emitter 51R configured to emit radiation in the red spectral range , so that a full color RGB display is provided .

[0078] In the exemplary embodiment illustrated in Figure IE , the optical sensor 1 comprises eight detection channels 2 . The detection channels 2 comprise a first set of detection channels 21 with a first detection channel 21B with a wavelength of maximum sensitivity in the blue spectral range , a second detection channel 21G with a wavelength of maximum sensitivity in a green spectral range , and a third detection channel 21R with a wavelength of maximum sensitivity in a red spectral range .

[0079] As Figure IE illustrates , the spectral sensitivities of the first detection channel 21B, the second detection channel 21G and the third detection channel 21R overlap with the emission spectra of the emitters 51B, 51G and 51R, respectively .

[0080] The detection channels 2 further comprise a second set of detection channels 22 . The second set of detection channels 22 comprises three detection channels 22A, 22B and 22C .

[0081] A wavelength of maximum sensitivity of the detector channel 22A is arranged between the wavelengths of maximum sensitivity of the first detection channel 21B and the second detection channel 21G . The detection channels 22B and 22C have wavelengths of maximum sensitivity located between the wavelengths of maximum sensitivity of the second detection channel 21G and the third detection channel 21R .

[0082] Further, the detection channels 2 comprise a third set of detection channels 23 . The third set of detection channels 23 comprises a detection channel 23A having a wavelength of maximum sensitivity smaller than the wavelength of maximum sensitivity of the first detection channel 21R . The wavelength of maximum sensitivity of the detection channel 23B of the third set 23 is larger than the wavelength of maximum sensitivity of the third detection channel 21R .

[0083] In the exemplary embodiment shown, the detection channels 2 are arranged in a spectrally equidistant manner . A full width at hal f maximum amounts to 120% of the spectral distance between adj acent detection channels 2 . The spectral distance between the wavelengths of maximum sensitivity of spectrally adj acent detection channels 2 amounts to 32 . 5 nm in each case . However, minor deviations from a spectrally equidistant arrangement are acceptable .

[0084] Figure IE further shows the spectral sensitivity of a silicon photodiode 60 without a filter and several examples of di f ferent spectra of ambient light 65 .

[0085] As Figure IE illustrates , the first set of detection channels

[0086] 21 covers the spectra of the emitters 51B, 51G, 51R of the display 5 so that these detection channels may be used for the compensation of unwanted back scattered light . The detection channels 2 of the second set of detection channels

[0087] 22 fill the spectral ranges between the detection channels of the first set of detection channels 21 .

[0088] Figure I F further illustrates the three color matching functions %(A), y( ), z( ) according to CIE1931 , wherein color matching function 8 Z (x( ) ) has a maximum in the blue spectral range , color matching function 8Y (y( ) ) has a maximum in the green spectral range and color matching function 8X (z( ) ) has its global maximum near 600 nm and a further local maximum in the blue spectral range .

[0089] The Figure further illustrates associated best match fitting curves 7 Z , 7Y and 7X which are obtained from a linear combination of the spectral sensitivities of the detection channels 2 . For example , the color matching function 8 Z overlaps with the spectral sensitivities over several detection channels 2 and may be approximated by a linear combination of the spectral sensitivities of these detection channels , wherein the detection channels 23A, 21B and 22A represent the main components .

[0090] The appropriate linear combinations of the signals of the detection channels 2 allow to obtain the tristimulus values X, Y, Z of the ambient light 65 with high accuracy . As Figure I F illustrates , there are only minor deviations between the color matching functions 8 Z , 8Y, 8X and their associated best match fitting curves 7 Z , 7Y, 7X .

[0091] As the detection channels 21B, 21G and 21R of the first set of detection channels 21 overlap with the associated emission spectra of the emitters 51B, 51G, 51R of the display 5 , the signal caused by unwanted back scattered light of the display 5 can be compensated for .

[0092] This helps to increase the contrast between the ambient light and the back scattered light to obtain the irradiance and / or the correlated color temperature of the ambient light 65 with suf ficient accuracy .

[0093] The detection channels of the third set of detection channels

[0094] 23 add additional spectral information near the short wavelength edge and the long wavelength edge of the visible spectral range .

[0095] The accuracy of the fit for the color matching functions 8X, 8Y, 8 Z by means of linear combinations may be further increased by speci fically adapting the shape and / or the width of the spectral sensitivity of each of the detection channels 2 .

[0096] The unwanted contribution of back scattered light of the display 5 can be estimated by a comparison of the signal from the first set of detection channels 21 to the mean signal of all detection channels 2 . I f the contribution is comparably large , the signals of the first set of detection channels 21 can be used to compensate for this contribution in order to obtain reliable information on the ambient light 65 as perceived by the human eye .

[0097] I f the contribution of the back scattered light is small compared to the ambient light 65 , the signal from all detection channels 2 may be used to obtain the correlated color temperature or the irradiance or to perform a spectral reconstruction, for instance for the purpose of light source identi fication .

[0098] Figures 2A and 2B refer to an exemplary embodiment of an optical sensor 1 that is substantially configured as described in connection with Figures 1A to I F . Unlike in the previous exemplary embodiment , the full width at hal f maximum of the detection channels 2 is 110% of the spectral distance between adj acent detection channels . Thus , the spectral overlap between adj acent detection channels is reduced . As Figure 2B illustrates , linear combinations of these spectral sensitivities allow to obtain a best match fitting curve 7X, 7Y, 7 Z for each color matching function 8X, 8Y, 8 Z with a good accuracy . However, a comparison with Figure I F reveals that the deviations between the best match fitting curves and the associated color matching functions increase i f the width of the spectral sensitivity is decreased .

[0099] Figure 3 relates to an exemplary embodiment of an optical sensor 1 that substantially corresponds to the exemplary embodiment described in connection with Figures 2A and 2B .

[0100] Unlike in the previous exemplary embodiment , the optical sensor 1 comprises detection channels 2 of a first set of detection channels 21 and a second set of detection channels 22 . Thus , the optical sensor 1 comprises six detection channels 2 , resulting in a reduced complexity of the optical sensor 1 . However, this is at the expense of reduced spectral information of the ambient light 65 at the short wavelength edge and the long wavelength edge of the visible spectrum .

[0101] Figure 4 schematically illustrates an exemplary embodiment of a method of producing an optical sensor . For the sake of better understanding the same reference signs as in the previous Figures are used for the features even i f the features are not explicitly shown in Figure 4 .

[0102] In a step S I spectral information on emitters 51B, 51G, 51R of a display 5 is provided .

[0103] In a step S2 a plurality of detection channels 2 is produced, wherein the detection channels 2 each comprise a photodetector 3 and a filter 4 , wherein the filters 4 of a first set of detection channels 21 are configured such that a spectral sensitivity of each detection channel 21B, 21G, 21R of the first set of detection channels 21 overlaps with an emission spectrum of an associated emitter 51B, 51G, 51R of the display 5 .

[0104] The filters 4 of a second set of detection channels 22 are configured such that wavelengths of maximum sensitivity of the detection channels 22A, 22B, 22C of the second set 22 are arranged between wavelengths of maximum sensitivity of the detection channels of the first set 21 .

[0105] The filters 4 of the detection channels 2 are configured such that a best match fitting curve 7 Z , 7Y, 7X for each of the three CIE1931 color matching functions 8 Z , 8Y, 8X is obtainable from a linear combination of the spectral sensitivities of the detection channels 2 .

[0106] Thus , the detection channels 2 can be speci fically adapted during production of the optical sensor 1 to the spectral properties of the emitters 51B, 51G, 51R of the display 5 .

[0107] In particular, the produced optical sensor 1 may be configured as described in the previous exemplary embodiments .

[0108] Figure 5 schematically illustrates an exemplary embodiment of a method of operating an electronic device 10 . For the sake of better understanding the same reference signs as in the previous Figures are used for the features even i f the features are not explicitly shown in Figure 5 . In a step S 10 an electronic device 10 is provided . In particular, the electronic device 10 may be configured as described in the previous exemplary embodiments .

[0109] In a step S2 an ambient light 65 is analyzed based on a signal of at least some of the detection channels 2 . Signals of the first set of detection channels 21 can be used to compensate for back scattered light from the emitters 51B, 51G, 51R .

[0110] In particular, the emitters 51B, 51G, 51R may emit light during the detection of the ambient light 65 . Thus , it is not necessary to detect the ambient light 65 during a dark period of the display 5 .

[0111] The signal of the optical sensor 1 may be used to adapt the display properties to the ambient light conditions .

[0112] Alternatively or in addition, a spectral reconstruction of the ambient light 65 may be performed, for instance in order to obtain information on the light sources providing the ambient light 65 .

[0113] This patent application claims the priority of German patent application 10 2024 108 260 . 7 , the disclosure content of which is hereby incorporated by reference .

[0114] The invention described herein is not restricted by the description given with reference to the exemplary embodiments . Rather, the invention encompasses any novel feature and any combination of features , including in particular any combination of features in the claims , even i f this feature or this combination is not itsel f explicitly indicated in the claims or exemplary embodiments . References

[0115] 1 optical sensor

[0116] 11 sensor chip

[0117] 12 sensor package

[0118] 13 aperture

[0119] 15 photosensitive area

[0120] 10 electronic device

[0121] 2 detection channel

[0122] 21 first set of detection channels

[0123] 21B first detection channel

[0124] 21G second detection channel

[0125] 21R third detection channel

[0126] 22 second set of detection channels

[0127] 22A, 22B, 22C detection channel of second set

[0128] 23 third set of detection channels

[0129] 23A, 23B detection channel of third set

[0130] 3 photodetector

[0131] 4 filter

[0132] 40 filter structure

[0133] 5 display

[0134] 51 pixel

[0135] 51B, 51G, 51R emitter

[0136] 60 sensitivity of silicon photodiode

[0137] 65 ambient light

[0138] 7X, 7Y, 7 Z best match fitting curve

[0139] 8X, 8Y, 8 Z color matching function

[0140] S I , S2 step

[0141] S 10 , S20 step

Claims

Claims1. An optical sensor (1) comprising a plurality of detection channels (2) , wherein- the detection channels (2) each comprise a photodetector (3) and a filter (4) to define a spectral sensitivity of the respective detection channel (2) ;- the detection channels (2) comprise a first set of detection channels (21) , the first set of detection channels (21) comprising a first detection channel (21B) with a wavelength of maximum sensitivity in a blue spectral range, a second detection channel (21G) with a wavelength of maximum sensitivity in a green spectral range, and a third detection channel (21R) with a wavelength of maximum sensitivity in a red spectral range;- the detection channels (2) comprise a second set of detection channels (22) , wherein wavelengths of maximum sensitivity of the detection channels of the second set (22) are arranged between wavelengths of maximum sensitivity of the detection channels of the first set; and- the spectral sensitivities of the detection channels (2) are configured such that a best match fitting curve (7Z, 7Y, 7X) for each of the three CIE1931 color matching functions (8Z, 8Y, 8X) is obtainable from a linear combination of the spectral sensitivities of the detection channels (2) .

2. The optical sensor according to claim 1, wherein- the second set of detection channels (22) comprises exactly one detection channel (22A) with a wavelength of maximum sensitivity between the wavelength of maximum sensitivity of the first detection channel (21B) and the wavelength ofmaximum sensitivity of the second detection channel ( 21G) ; and- the second set of detection channels comprises exactly two detection channels ( 22B, 22C ) with a wavelength of maximum sensitivity between the wavelength of maximum sensitivity of the second detection channel ( 21G) and the wavelength of maximum sensitivity of the third detection channel ( 21R) .3 . The optical sensor according to claim 2 , wherein the wavelengths of maximum sensitivity of the detection channels of the first set ( 21 ) and of the second set ( 22 ) taken together are arranged in a spectrally equidistant manner with a tolerance of at most 10 % .4 . The optical sensor according to any one of the preceding claims , wherein the detection channels ( 2 ) comprise a third set of detection channels ( 23 ) , wherein- a wavelength of maximum sensitivity of at least one of the detection channels of the third set of detection channels ( 23 ) is smaller than the wavelength of maximum sensitivity of the first detection channel ( 21B ) ; and / or- a wavelength of maximum sensitivity of at least one of the detection channels of the third set of detection channels ( 23 ) is larger than a wavelength of maximum sensitivity of the third detection channel ( 21R) .5 . The optical sensor according to any one of the preceding claims , wherein a full width at hal f maximum of a spectral sensitivity of at least one of the detection channels ( 2 ) is at least 90 % and at most 150 % of an average spectraldistance between two spectrally adjacent detection channels(2) .

6. The optical sensor according to any one of the preceding claims , wherein the wavelengths of maximum sensitivity of the detection channels of the first set (21) , the second set (22) , and the third set (23) taken together are arranged in a spectrally equidistant manner with a tolerance of at most 10 %.

7. A method of producing an optical sensor (1) configured as an ambient light sensor behind a display (5) , comprising the steps of: a) providing spectral information on emitters (51B, 51G, 51R) of the display (5) ; b) producing a plurality of detection channels (2) , the detection channels (2) each comprising a photodetector (3) and a filter (4) , wherein- the filters (4) of a first set of detection channels (21) are configured such that a spectral sensitivity of each detection channel (21B, 21G, 21R) of the first set of detection channels (21) overlaps with an emission spectrum of an associated emitter (51B, 51G, 51R) ;- the filters (4) of a second set of detection channels (22) are configured such that wavelengths of maximum sensitivity of the detection channels (22A, 22B, 22C) of the second set (22) are arranged between wavelengths of maximum sensitivity of the detection channels of the first set (21) ; and- the filters (4) of the detection channels (2) are configured such that a best match fitting curve (7Z, 7Y, 7X) for each of the three CIE1931 color matching functions (8Z,8Y, 8X) is obtainable from a linear combination of the spectral sensitivities of the detection channels (2) .

8. The method according to claim 7, wherein an optical sensor (1) according to any one of claims 1 to 6 is produced.

9. An electronic device (10) comprising an optical sensor (1) according to one of the preceding claims and a display (5) with a plurality of pixels (51) , the pixels comprising emitters (51B, 51G, 51R) with emission spectra in the blue, green and red spectral ranges, wherein the spectral sensitivities of the detection channels of the first set of detection channels (21) overlap with the respective emission spectra of the emitters (51B, 51G, 51R) .

10. The electronic device according to claim 9, wherein the optical sensor (1) is arranged behind the display (5) in a top view onto the display (5) .

11. The electronic device according to claim 9 or 10, wherein the optical sensor (1) is configured to analyze an ambient light (65) during operation of the display (5) .

12. The electronic device according to any one of claims 9 to 11, wherein the optical sensor (1) is configured to compensate for back scattered light from the emitters (51B, 51G, 51R) by means of the first set of detection channels (21) .

13. The electronic device according to any one of claims 9 to 11, wherein the electronic device (10) is configured to adapt awhite point of the display (5) based on a signal from the optical sensor (1) .

14. A method of operating an electronic device (10) according to any one of claims 9 to 13, wherein an ambient light (65) is analyzed based on a signal of at least some of the detection channels (2) .

15. The method according to claim 14, wherein at least some of the emitters (51B, 51G, 51R) are operated during the detection of the ambient light (65) .

16. The method according to claim 14 or 15, wherein signals of the first set of detection channels (21) are used to compensate for back scattered light from the emitters (51B, 51G, 51R) .

17. The method according to any one of claims 14 to 16, wherein a spectral reconstruction of the ambient light (65) is performed.

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