Proximity detection with automatic calibration

Abstract

An optical device (1) comprises an emitter (3) for emitting light, a receiver (4) for receiving reflected light and providing a data signal (15), a register (5) for storing processing parameters, said processing parameters comprising a baseline reference value (16), and a processing unit (6) for processing the data signal (15) using said processing parameters. The processing unit (6) is configured to compare the data signal (15) with the baseline reference value (16) and determine, based at least in part on the comparison, that a crosstalk calibration of the optical device is required.

Description

Technical Field

[0001] This disclosure relates to optical devices, and particularly, but not exclusively, to proximity sensors with automatic calibration. Background Technology

[0002] Proximity sensing is used in many modern electronic devices, including mobile devices such as smartphones, to measure the presence of an object and / or the distance to that object. For example, a proximity sensor in a smartphone can be used to detect when a user brings the phone to their ear, in response to which the display can be turned off.

[0003] Optical proximity detection typically measures the intensity of reflected light to determine the distance to an object. Proximity sensors always experience some degree of unwanted crosstalk, where the received signal is a superposition of crosstalk and "true" proximity data from the target reflection. Crosstalk can originate from various sources, such as internal reflections. In proximity systems, optical crosstalk must be accurately measured under 'targetless' conditions and subtracted from the proximity measurement to obtain the true proximity data.

[0004] Crosstalk calibration is required when conditions change (which may alter crosstalk). This can be caused by factors such as changes in proximity configuration settings, temperature variations, or contamination in the optical path. Changes in crosstalk affect proximity data and can potentially increase the error failure rate. To avoid this, calibration should be performed whenever crosstalk changes. Typically, this is triggered by the application software.

[0005] Offsets may also exist in the device's analog front-end (AFE), which causes the final code to shift and manifest as crosstalk. Crosstalk calibration can also compensate for this shift, and no explicit electrical calibration is required.

[0006] In conventional proximity measurements, additional transmitters and / or sensors are used to detect the presence of smudges on the screen. The sensors / transmitters are physically positioned such that reflected signals are only detected if a smudge is present on the screen. Therefore, the presence of a smudge is detected by monitoring the signal level. In another approach, application software monitors the range of proximity data and uses algorithms to detect smudges.

[0007] Therefore, the problem with conventional proximity sensors is the need for additional hardware (e.g., transmitters and receivers) and / or the added processing burden imposed on the host application to analyze device data in order to detect the presence of dirt in front of the sensor. Summary of the Invention

[0008] To address at least some of the aforementioned problems, this disclosure provides an optical device (typically a proximity sensor) with built-in processing of the data signal provided by the device to determine whether calibration is required. Because the device's normal data signal (e.g., a proximity data signal) is used, no additional transmitter or receiver is needed to detect smudges that cause crosstalk variations and therefore require calibration. Furthermore, since the signal is processed at the device itself, it does not need to be continuously transmitted to and analyzed by external application software, thus reducing the overhead on the host / software for tracking the range of data used to detect smudges.

[0009] According to a first aspect of this disclosure, an optical device is provided, comprising: a transmitter for emitting light; a receiver for receiving reflected light and providing a data signal; and a register for storing processing parameters, the processing parameters including a baseline reference value. The device further includes a processing unit for processing the data signal using the processing parameters, wherein the processing unit is configured to compare the data signal with the baseline reference value and, at least in part, determine that crosstalk calibration of the optical device is required based on the comparison. Typically, the optical device is a proximity sensor, and the data signal is a proximity data signal that can be used to determine the presence of an object or the distance to that object, which reflects light emitted by the transmitter and received by the receiver.

[0010] The processing unit can be configured to perform crosstalk calibration in response to determining that crosstalk calibration is needed; or to mark an external unit as needing crosstalk calibration, wherein the processing unit is configured to receive a calibration trigger from the external unit and perform crosstalk calibration in response to receiving the calibration trigger. Typically, the optical device is integrated into a mobile device such as a smartphone and sends a calibration request to the mobile device, which analyzes the request and triggers calibration if necessary. However, the device can also be configured to perform calibration automatically when it determines that calibration is needed. Registers can be configured by an external unit. For example, the external unit can set and maintain one or more processing parameters in the registers. In particular, thresholds, average window size, and persistent filter values ​​can be programmable. The optical device can communicate with the external unit using, for example, the I2C protocol. Other possible communication protocols include SPI, I3C, and UART, or other custom or standard serial or parallel protocols.

[0011] Crosstalk calibration (also referred to herein as "calibration") may include determining a crosstalk value that indicates the level of optical crosstalk at the receiver, wherein a processing unit is configured to subtract the crosstalk value from a data signal. The processing unit subtracts the crosstalk value to obtain a "true" data signal (e.g., true proximity data for determining the presence of a target object or the distance to a target object).

[0012] Processing parameters may include a baseline window size (e.g., 2, 4, 8, 16, 32, etc.) and a no-target threshold. The processing unit can be configured to determine the baseline value of the data signal by averaging the data signal within a window of the baseline window size, ignoring data signal values ​​exceeding the no-target threshold. The processing unit is then configured to compare the data signal to a baseline reference value by comparing the baseline value to a baseline reference value. For example, comparing the baseline value to the baseline reference value includes calculating the absolute difference between the baseline value and the baseline reference value and determining when the absolute difference exceeds the baseline threshold in a register.

[0013] The register may also include a persistence value indicating a time period, and a smudge threshold. The processing unit can be configured to determine whether a baseline value exceeds the smudge threshold over that time period in response to determining that the absolute difference exceeds the threshold. Typically, this time period is given by the number of consecutive periods in which the baseline value is measured. For example, a persistence filter can be set to four, where four indicates a time period represented by four periods, meaning the sensor checks whether the baseline value exceeds the smudge threshold in four consecutive baseline value calculations. In response to determining that the baseline value exceeds the smudge threshold over that time period, the processing unit is configured to determine that crosstalk calibration is required. The processing unit can set a "smudge detected" flag to equal 1.

[0014] The optical device may also include a temperature sensor (e.g., a thermistor) for determining the temperature of the optical device or at the location of the optical device. Processing parameters then include a temperature threshold, and the processing unit is configured to compare the temperature of the optical device with the temperature threshold and determine that crosstalk calibration is needed when the temperature of the optical device exceeds the temperature threshold. The processing unit may set a "temperature exceeds threshold" flag equal to 1. Typically, the absolute difference between the device's temperature and the nominal temperature (stored in a register) is taken and compared with the temperature threshold. In this way, only one threshold is used to detect both negative and positive temperature changes. After calibration, the nominal temperature can be updated to the current temperature.

[0015] Preferably, the processing unit is configured to determine the need for crosstalk calibration when the optical device is turned on (i.e., when the optical device changes from "disabled" to "enabled"), because device settings that may affect crosstalk may change when the device is disabled.

[0016] According to a second aspect of this disclosure, a system is provided that includes a proximity sensor according to the first aspect and a mobile device (e.g., a smartphone or smartwatch) connected to the proximity sensor and including application software. The application software is configured to set and maintain one or more processing parameters in registers of the proximity sensor. The application software is also configured to receive a request from the proximity sensor regarding crosstalk calibration, and in response to receiving the request, determine whether to send a calibration trigger to the proximity sensor to induce crosstalk calibration. The host application software may take into account further factors to determine whether device calibration is truly necessary.

[0017] According to a third aspect of this disclosure, a method is provided for determining the presence of an object or the distance to an object. This method can be performed using an optical device according to the first aspect. The method includes: emitting light from a transmitter; receiving light using a receiver, the light comprising light emitted from the transmitter and reflected by an object; and providing a data signal that can be used to determine the presence of the object and / or the distance to the object. The method further includes: providing a register including processing parameters for processing the data signal, the processing parameters including a baseline reference value; comparing the data signal to the baseline reference value; and determining, at least in part, that the optical device needs crosstalk calibration based on the comparison. The method also includes determining the presence of an object or the distance to an object based on the data signal. When a target is present, the data signal is used for proximity sensing, i.e., for detecting a target object. When no target is present (when the baseline value is below a target-free threshold), the data signal is used in baseline calculation as part of an algorithm for determining whether calibration is required.

[0018] The method may also include performing the following operations in response to determining that crosstalk calibration is required: performing crosstalk calibration; or marking the need for crosstalk calibration to an external unit, receiving a calibration trigger from the external unit, and performing crosstalk calibration in response to receiving the calibration trigger.

[0019] Processing parameters may include a baseline window size (e.g., 2, 4, 8, 16, 32, etc.), a baseline threshold, and a no-target threshold. The method may then further include: determining a baseline value for the data signal by averaging the data signals within a window of the baseline window size while ignoring data signal values ​​exceeding the no-target threshold; and comparing the data signal to the baseline reference value by taking the absolute difference between the baseline value and a baseline reference value and determining when that absolute difference exceeds the baseline threshold.

[0020] The register may also include a persistent value indicating a time period (typically a continuous baseline value period / calculation), and a smudge threshold. The method may then further include: determining whether a baseline value exceeds the smudge threshold over that time period in response to determining that the absolute difference exceeds the threshold; and determining that crosstalk calibration is required in response to determining that the baseline value exceeds the smudge threshold over that time period. Alternatively or additionally, the register may include a temperature threshold, and the method may include: measuring a temperature in response to determining that the absolute difference exceeds the baseline threshold; comparing that temperature to a nominal temperature; and determining that crosstalk calibration is required when the absolute difference between the temperature and the nominal temperature exceeds the temperature threshold. Attached Figure Description

[0021] Specific embodiments of this disclosure will now be described with reference to the accompanying drawings, in which...

[0022] Figure 1 An optical device according to an embodiment of the present disclosure is described;

[0023] Figure 2 A system including an optical device according to an embodiment is described;

[0024] Figure 3 Another system including an optical device according to an embodiment is described;

[0025] Figure 4 A flowchart illustrating the operation of an optical device according to an embodiment is depicted; and

[0026] Figure 5 A graph depicts the time-varying nature of the proximity data signal with respect to different processing parameters of the optical device according to the embodiment. Detailed Implementation

[0027] Figure 1 A schematic diagram of an optical device 1 is shown, which is a proximity sensor for determining the presence of an object 2 and / or the distance to the object 2. The proximity sensor includes an emitter 3 for emitting light (e.g., IR light), which is reflected from the object 2 and received by a receiver 4. The receiver 4 may include a receiving circuitry system such as an analog-to-digital converter (ADC). The receiver 4 converts the received light into a data signal that includes proximity data, based on which the presence of the object 2 can be determined.

[0028] The sensor also includes register 5, which has processing parameters such as a baseline reference value, which is an average reference / nominal value of the data signal when no object 2 is sufficiently close to reflect light back to receiver 4 (i.e., targetless condition). Other processing parameters typically include a threshold for triggering calibration (or a request for calibration) and a baseline window size for calculating the average of the data signal. Register 5 is typically comprised of local memory within the sensor. Typically, for example, when the sensor is used with a mobile device, register 5 is maintained by application software. For instance, the application software may determine appropriate values ​​for thresholds for a particular application and update register 5 accordingly.

[0029] The sensor includes a processing unit 6 for processing data signals. The processing unit 6 can access register 5 and use processing parameters to correctly process the data signals. For example, the processing unit 6 can subtract crosstalk values ​​from the data signals to separate "true" proximity data from the crosstalk.

[0030] Processing unit 6 is configured to calculate the baseline value of the data signal by averaging the data signal using multiple data points equal to the baseline window size. Processing unit 6 is configured to compare the data signal with a targetless threshold and calculate the baseline value only under the targetless condition (i.e., when the data signal is below the threshold). For example, processing unit 6 can be configured to ignore data points with values ​​greater than the targetless threshold in the calculation of the baseline value.

[0031] If the difference between the baseline value and the baseline reference value exceeds a threshold, the processing unit 6 is configured to determine whether there is a temperature change and / or whether there is a “smudge” in front of the sensor (a smudge is defined as any semi-permanent interference in the optical path of the sensor, such as grease or dirt on a smartphone screen).

[0032] To detect temperature changes, processing unit 6 is configured to compare the current temperature, as measured by temperature sensor 7, with the nominal temperature. The nominal temperature is typically the temperature measured by temperature sensor 7 during its last calibration and stored in register 5. Processing unit 6 is configured to compare the absolute difference between the current temperature and the nominal temperature with a temperature threshold. If the difference exceeds the threshold, processing unit 6 determines that the proximity sensor needs calibration. In response, processing unit 6 can be configured to trigger automatic calibration of the proximity sensor or to request calibration from an external unit 8 (e.g., a mobile device such as a smartphone with application software). For example, processing unit 6 can set a temperature flag to 1 and send an interrupt to external unit 8. If external unit 8 deems calibration necessary, it sends a calibration request to the proximity sensor, which performs calibration in response. During calibration, the nominal temperature value stored in register 5 is updated.

[0033] To detect smudges, processing unit 6 is configured to calculate the baseline value of the data signal over a time period represented by multiple cycles (i.e., within multiple consecutive baseline window sizes) to determine whether the baseline value remains above (or below) a smudge threshold during that time period. Register 5 includes a persistence value that determines the number of cycles and thus the time period. The persistence value can be user / application-defined and takes into account the semi-permanent nature of smudges (as opposed to transient objects that briefly obscure the sensor). If the baseline value remains above (or below) the smudge threshold during that time period, processing unit 6 determines that a smudge exists (or has been removed) and therefore determines that calibration is required. For example, processing unit 6 can set a smudge flag to 1 and send an interrupt to external unit 8, or processing unit 6 can trigger automatic calibration.

[0034] The proximity sensor is configurable, allowing the application software to set how the sensor responds to the detection of dirt and / or temperature changes. For example, the application software of external unit 8 can configure register 5 so that processing unit 6 responds by automatically calibrating the proximity sensor whenever dirt and / or temperature changes are detected. Alternatively, the register can be configured so that processing unit 6 simply flags a "problem" for the application software and then performs calibration in response to receiving the prompt.

[0035] Processing unit 6 can also be configured to trigger calibration when the proximity sensor is turned on (i.e., when the proximity sensor switches from off to on). Typically, the proximity sensor is turned off when configuration settings change—which can affect crosstalk. Therefore, instead of checking whether the settings have changed and thus whether crosstalk has changed, the proximity sensor is automatically calibrated when device 1 is turned on again.

[0036] The advantage of optical device 1 is that it eliminates the need for an additional transmitter or receiver for stain detection; instead, it can utilize the data signal provided by the standard transmitter 3 and receiver 4. Furthermore, because optical device 1 is configured to process the data signal to determine the presence of stains, the data signal does not need to be continuously transmitted to and analyzed by external application software. Therefore, more processing is performed directly at optical device 1. This significantly reduces the bandwidth load on the optical device's output. For example, optical device 1 can communicate with external unit 8 via an I2C connection. Because the processing unit of optical device 1 determines whether calibration is required, only calibration triggers / requests and status flags (e.g., stain flag = 1) need to be transmitted via the I2C connection, rather than the entire data signal.

[0037] External unit 8 can influence data processing at optical device 1 by setting the values ​​of at least some processing parameters in register 5. For example, a small baseline window size can be set if a fast response to changes in crosstalk is required.

[0038] Figure 2 A schematic diagram of system 9 in smartphone 10 is shown, system 9 including, etc. Figure 1 The optical device 1 of the proximity sensor is depicted in the figure. The same reference numerals are used in different figures for equivalent or similar features to aid understanding and are not intended to limit the embodiments shown. The smartphone 10 may be... Figure 1 The external unit 8 is shown. In use, the optical device can be used to determine the presence of the user of the smartphone 10 and / or the distance to that user.

[0039] Figure 3 A schematic diagram of system 9 is shown, which includes: an optical device 1, for example... Figure 1 The device includes a proximity sensor; a display 11 (e.g., an LED or OLED display); and a cover glass 12. The display 11 and cover glass 12 can be from a smartphone, for example... Figure 2 A portion of the smartphone 10 shown. A stain 13 is located on the cover glass in front of the optical device 1. Although Figure 3 The optical device 1 is shown to be located next to the display 11, but in other embodiments, the optical device 1 may be located below the display 11.

[0040] Optical device 1 emits light 14, which is transmitted through cover glass 12. Light scattered from stain 13 increases optical crosstalk at the receiver of optical device 1, and thus increases the baseline value of the data signal provided by the receiver. Optical device 1 is configured to detect this increase in the baseline value of the data and to determine that a stain is present in front of device 1. In response, optical device 1 can trigger crosstalk calibration to update the crosstalk value to be subtracted from the data signal.

[0041] If and when the smudge 13 is removed, the optical crosstalk will decrease. The optical device 1 is configured to detect this change and determine that the smudge has been removed. In response, the device 1 can trigger another crosstalk calibration to update the crosstalk value to be subtracted from the data signal.

[0042] Figure 4 A flowchart illustrating the sequence of steps taken by the proximity sensor according to an embodiment is shown.

[0043] Starting from the "idle" state, if "Calibration Enable" = 1, the sensor performs calibration and sets "calib_finished" = 1.

[0044] If "Prox.Enable" = 0, the sensor returns to the "idle" state.

[0045] If "Prox.Enable" = 1 (i.e., enable the proximity sensor for proximity measurement), the sensor performs "Run Proximity" and "Calculate BSLN" (i.e., determine the baseline value of the proximity data signal).

[0046] If the baseline value is within the limits (i.e., the absolute difference between the calculated baseline value and the baseline reference value is less than the threshold), the sensor repeats the "running proximity" and "calculating BSLN". Otherwise, the sensor performs "detecting dirt and temperature changes" (i.e., determining whether there is a temperature change or dirt in front of the sensor that causes a change in crosstalk).

[0047] The sensor then checks for "stains or temperature changes detected?". If no temperature changes or stains are detected, the sensor returns to "Run Proximity" and "Calculate BSLN". Otherwise, with "Interrupt Enabled" enabled, the sensor performs "Interrupt Enabled" (i.e., sends an interrupt to trigger a calibration request from an external unit).

[0048] The sensor then checks if "Calibration Enable" = 1 (i.e., a calibration request has been received) or "auto_calib_trigger_en" (i.e., automatic sensor calibration is enabled). If so, the sensor performs calibration. Otherwise, the sensor returns to "Run Proximity" and "Calculate BSLN".

[0049] The averaging window used to calculate the baseline value is configurable. Interruptions can be enabled or disabled. "Prox.Enable" and "Calibration Enable" are user-controllable (e.g., via application software).

[0050] In this implementation, the proximity sensor can perform the following three steps to detect the conditions that trigger calibration.

[0051] 1. Baseline (BSLN data) measurement:

[0052] The baseline is the average of the proximity data. The averaging window size can be configured to 2, 4, 8, 16, 32, etc. (multiples of 2). Proximity data used for baseline calculation is only considered when there is no target. This is only achieved by updating the BSLN average when the proximity data is less than the programmable 'no target' data threshold (NT-Limit) and the device is in detection mode (i.e., the screen is on and no target is approaching). At the end of the BSLN averaging window, the calculated baseline value (BSLN_DATA) is compared with the software-configured reference baseline value (I2C_REF_BSLN_DATA).

[0053] If |BSLN_DATA - I2C_REF_BSLN_DATA| > BSLN_DELTA_THR, then the flag ('bsln_ovr_thr') is set, and the algorithm proceeds to the temperature measurement and stain detection phase. BSLN_DELTA_THR is a software-programmable register that sets a threshold for the difference between the measured baseline data and the reference baseline data. For the above comparison, only the magnitude of the difference is considered. This allows the sensor to track both increases and decreases in the measured baseline.

[0054] 2. Temperature measurement and comparison:

[0055] In a rough step, an on-chip temperature sensor (e.g., a thermistor) is used to measure and detect temperature changes.

[0056] Temperature can be measured by the device in the following two situations:

[0057] a) After each calibration cycle used to record reference temperature data (CALIB_TEMP_DATA), the reference temperature data will be used for comparison in subsequent proximity measurement cycles; and

[0058] b) After a normal proximity measurement is performed when the BSLN data exceeds the threshold. The data can be stored in the TEMP_DATA register.

[0059] If |TEMP_DATA - CALIB_TEMP_DATA| > TEMP_DELTA_THR, then the flag ('temp_ovr_thr') is set. TEMP_DELTA_THR is a software-programmable register that sets the threshold difference between the measured temperature data and the reference temperature data.

[0060] If 'bsln_ovr_thr' = 1 and 'temp_ovr_thr' = 1, then an interrupt can also be generated when the application software triggers a calibration request, and optionally, the calibration cycle can be automatically triggered.

[0061] 3. Stain detection:

[0062] If the BSLN exceeds a threshold, a temperature measurement is performed, followed by stain detection. Stains are represented by a constant (or semi-permanent) shift rather than a drift in the data. The algorithm uses this concept to detect stains. Stain detection is performed by examining the baseline data after continuous filtering. During the stain detection state, the BSLN data is compared to a software-programmable 'SMDG_THR' threshold.

[0063] If BSLN_DATA > SMDG_THR for N consecutive BSLN cycles, then set the flag ('smdg_detected'). N is the continuous filter setting and can take values ​​of 0 (each BSLN reaches the threshold), 1 (BSLN reaches the threshold twice), 2, 3, ..., M.

[0064] If 'bsln_ovr_thr' = 1 and 'smdg_detected' = 1, an interrupt can also be generated when the application software triggers a calibration request, and optionally, the calibration cycle can be automatically triggered.

[0065] Figure 5 The graph shows the time-varying nature of the data signal 15 with respect to different processing parameters. Initially, the data signal is close to the baseline reference value 16 (i2c_ref_bsln = nt_data). This is followed by significant fluctuations in region 17. Within region 17, the data signal exceeds the baseline thresholds 18 and 19 (bsln_del_threshold_+ and bsln_del_threshold_-). However, because the baseline value is an average (within the baseline window) and / or due to transient changes in crosstalk filtering of persistent values, no smudges are detected at this point. Although signal 15 fluctuates in region 17, it briefly exceeds the targetless threshold 21 (NT_Limit) at point 20. The data at point 20 can be ignored and is not used to calculate the baseline value.

[0066] After significant fluctuations, the baseline value stabilized above the smudge threshold 22 (smudge_threshold+). In region 23, a smudge was detected because the baseline value was below the no-target threshold 21, but greater than the smudge threshold 22 within a period equal to the duration of the smudge value. The smudge detection flag can be set to 1.

[0067] After the stain was detected, a significant fluctuation in signal 15 occurred in region 24. Again, the window size used to calculate the baseline value and the persistence value were used to filter out these abrupt changes in the data. Data points in region 25 above the target threshold 21 were ignored.

[0068] Signal 15 stabilizes below the lower smudge threshold 26 (smudge_threshold-). In region 27, a smudge is detected (in this case, smudge removal) because the baseline value is below the no-target threshold 21 and below the lower smudge threshold 26 for a number of periods equal to the duration value. The smudge detection flag can be set to 1.

[0069] like Figure 5 As can be seen, the algorithm ignores the data whenever it approaches a sharp change. Whenever the baseline stabilizes outside the smudge threshold and remains within the "no target" limit for N consecutive cycles (N = duration value), the algorithm alerts the host and can also perform automatic calibration to compensate for the smudge.

[0070] Therefore, a calibration request / trigger can be executed under the following conditions: (bsln_ovr_thr = 1) and ((temp_ovr_thr = 1)|(smdg_detected = 1)).

[0071] The embodiments described herein offer several advantages over conventional devices. No additional transmitters, sensors, analog front-ends, or special packaging are required to detect the presence or removal of dirt. For proximity sensors, the same circuitry used to measure proximity is used to detect dirt, without relying on any other external circuitry. The sensor can detect changes in conditions related to temperature variations, the presence / removal of dirt, and configuration changes that affect crosstalk and thus proximity data. Additionally, the sensor can request / trigger calibration to mitigate the effects of these factors.

[0072] The optical device offers flexibility through user-programmable registers to configure the range via thresholds and reference values, and the response time via baseline averaging windows and duration values ​​(filter size). This provides the option to customize calibration algorithms based on applications in the art. The device can provide a two-step process: examining baseline data (long-term averaged data) and then monitoring for temperature changes and the presence of contaminants. This improves the reliability of detection regarding the conditions that trigger calibration. Furthermore, because the data signal is processed at the device, this eliminates the overhead associated with the host / software for tracking the range of data used to detect contaminants.

[0073] Although specific embodiments have been described above, the claims are not limited to these embodiments. Each disclosed feature may be incorporated, individually or in appropriate combination with other features disclosed herein, into any of the described embodiments.

[0074] Figure Labels

[0075] 1 Optical device 15 Data signal

[0076] 2 objects, 16 baseline reference values

[0077] 3 transmitters 17 have areas with large fluctuations

[0078] 4 receivers, 18 baseline thresholds

[0079] 5 registers 19 baseline threshold

[0080] 6 processing units, 20 data points above the target threshold

[0081] 7 Temperature sensor 21 No target threshold

[0082] 8 External Units 22 Stain Threshold

[0083] 9. System 23 detected areas of stains.

[0084] 10 Smartphones 24 Areas with Significant Fluctuations

[0085] 11 monitors showed 25 data points above the target threshold.

[0086] 12-cover glass with 26 stain threshold

[0087] 13 Stains 27 Areas where stains were detected

[0088] 14 emitted light

Claims

1. An optical device (1), comprising: Emitter (3), the emitter (3) is used to emit light; Receiver (4), the receiver (4) is used to receive reflected light and provide data signal (15); Register (5) is used to store processing parameters, including baseline reference value (16), baseline window size and no target threshold (21). as well as Processing unit (6), the processing unit (6) being configured to process the data signal (15) using the processing parameters, wherein the processing unit (6) is configured to: The baseline value of the data signal (15) is determined by averaging the data signal (15) in a window with the baseline window size, ignoring data signal values ​​exceeding the target threshold (21). The data signal (15) is compared with the baseline reference value (16) by comparing the baseline value with the baseline reference value (16), and the need for crosstalk calibration of the optical device (1) is determined at least in part based on the comparison.

2. The optical device (1) according to claim 1, wherein, The processing unit (6) is configured to respond to determining that the crosstalk calibration is required. Perform the crosstalk calibration, or The processing unit (6) is configured to receive a calibration trigger from the external unit (8, 10) and perform the crosstalk calibration in response to receiving the calibration trigger.

3. The optical device (1) according to claim 2, wherein, The register (5) can be configured by the external unit (8, 10).

4. The optical device (1) according to claim 1, wherein, The crosstalk calibration includes determining a crosstalk value that indicates the level of optical crosstalk at the receiver (4), and wherein the processing unit (6) is configured to subtract the crosstalk value from the data signal (15).

5. The optical device (1) according to claim 1, wherein, The processing parameters also include a baseline threshold (18), and wherein comparing the baseline value with the baseline reference value (16) includes calculating the absolute difference between the baseline value and the baseline reference value (16) and determining when the absolute difference exceeds the baseline threshold (18).

6. The optical device (1) according to claim 5, wherein, The register (5) includes: Indicates the duration of a time period, and Stain threshold (22). Furthermore, the processing unit (6) is configured to: In response to determining that the absolute difference exceeds the baseline threshold (18), it is determined whether the baseline value exceeds the stain threshold (22) over the time period, and In response to determining that the baseline value exceeds the smudge threshold (22) over the time period, it is determined that the crosstalk calibration is required.

7. The optical device (1) according to claim 5 or 6 further includes a temperature sensor (7) for determining the temperature of the optical device (1), wherein, The processing parameters also include a temperature threshold, and wherein the processing unit (6) is configured to: In response to determining that the absolute difference exceeds the baseline threshold (18), the temperature of the optical device (1) is compared with the temperature threshold, and When the temperature of the optical device (1) exceeds the temperature threshold, it is determined that the crosstalk calibration is required.

8. The optical device (1) according to claim 1, wherein, The processing unit (6) is also configured to determine the need for crosstalk calibration when the optical device (1) is turned on.

9. The optical device (1) according to claim 1, wherein, The optical device (1) is a proximity sensor, and the data signal (15) is a proximity data signal that can be used to determine the presence of an object (2) or the distance to the object (2), which reflects light emitted by the transmitter (3) and received by the receiver (4).

10. A system (9) comprising: The proximity sensor according to claim 9; as well as Mobile device (10), the mobile device (10) being connected to the proximity sensor and including application software, wherein the application software is configured to: Set and maintain one or more of the processing parameters in the register (5) of the proximity sensor. Receive a request for crosstalk calibration from the proximity sensor, and In response to receiving the request, determine whether to send a calibration trigger to the proximity sensor to induce the crosstalk calibration.

11. A method for determining the existence of an object (2) or the distance to the object (2), the method comprising: Light is emitted from the transmitter (3); Light is received using a receiver (4), the light comprising light emitted from the transmitter (3) and reflected by the object (2); The receiver (4) provides data signals (15) that can be used to determine the presence of the object (2) or the distance to the object (2); A register (5) is provided that includes processing parameters for processing the data signal (15), the processing parameters including a baseline reference value (16), a baseline window size, and a targetless threshold (21). The baseline value of the data signal (15) is determined by averaging the data signal (15) in a window with the baseline window size, ignoring data signal values ​​exceeding the target threshold (21). The data signal (15) is compared with the baseline reference value (16) by comparing the baseline value with the baseline reference value (16); The need for crosstalk calibration is determined at least in part based on the comparison. as well as The presence of the object (2) or the distance to the object (2) is determined based on the data signal (15).

12. The method of claim 11, further comprising: In response to determining that the crosstalk calibration is required, Perform the crosstalk calibration, or The crosstalk calibration is required for the external unit (8, 10); The calibration trigger is received from the external unit (8, 10), and the crosstalk calibration is performed in response to receiving the calibration trigger.

13. The method according to claim 11 or 12, wherein, The processing parameters also include a baseline threshold (18), and wherein comparing the baseline value with the baseline reference value (16) includes calculating the absolute difference between the baseline value and the baseline reference value (16) and determining when the absolute difference exceeds the baseline threshold (18).

14. The method according to claim 13, wherein, The register (5) also includes: Indicates the duration of a time period, and Stain threshold (22), and the method further includes: In response to determining that the absolute difference exceeds the baseline threshold (18), it is determined whether the baseline value exceeds the stain threshold (22) over the time period; and In response to determining that the baseline value exceeds the stain threshold (22) over the time period, it is determined that the crosstalk calibration is required; and / or The register (5) further includes a temperature threshold, and the method further includes: In response to determining that the absolute difference exceeds the baseline threshold (18), the temperature is measured; Compare the temperature to the nominal temperature; and When the absolute difference between the temperature and the nominal temperature exceeds the temperature threshold, it is determined that the crosstalk calibration is required.

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