Time-of-flight path delay compensation

Abstract

The embodiment of the invention relates to time-of-flight path delay compensation. A time of flight (TOF) sensor includes a timing generator that generates a timing reference, a first array of TOF-related components including rows of TOF-related components, where each row receives the timing reference, and a virtual row of TOF-related components. The TOF sensor also includes a second array of TOF-related components, the second array including rows of TOF-related components, where each row receives a timing reference, and a virtual row of TOF-related components. A first path delivers a timing reference to a row of the first array, the first path starting from the timing generator through a virtual row of TOF-related components in the second array to the first array of TOF-related components. A second path delivers the timing reference to a row of the second array, the second path starting from the timing generator through a virtual row of TOF-related components in the first array to the second array of TOF-related components.

Description

Technical Field

[0001] The present disclosure relates to the field of optical sensing, and in particular to equalizing the response times of reference and return single photon avalanche diode (SPAD) arrays in time-of-flight (TOF) sensors. Background Art

[0002] Time-of-flight (TOF) sensors are components used in various advanced technologies to accurately measure the distance to an object. Applications for such TOF sensors span multiple technology areas, including autonomous navigation for vehicles and drones, 3D mapping and imaging, virtual and augmented reality systems, gesture recognition in consumer electronics, and facial recognition in consumer electronics.

[0003] Direct time-of-flight (dTOF) sensors and indirect time-of-flight (iTOF) sensors are two variations of TOF technology. dTOF sensors work by emitting short pulses of light toward a target and measuring the time it takes for the light to reflect from the target and return to the sensor. This approach can accurately measure the distance to a target. iTOF sensors, on the other hand, operate by emitting a continuous wave of modulated light and measuring the phase shift between the emitted and reflected light waves. While iTOF sensors can also calculate distance, they are generally not as accurate as dTOF sensors at making precise measurements, especially at longer distances or in brightly lit environments. However, iTOF sensors tend to be more energy-efficient and less expensive to produce, which makes them more ideal for certain applications, such as arrays with high resolutions (such as VGAs).

[0004] Now refer to Figure 1 A dTOF sensor 10 is described. The dTOF sensor 10 is embedded in a housing 11 which is divided into two cavities: an exit cavity 12 and an entrance cavity 13 separated by an optical barrier 14 .

[0005] Within the exit cavity 12, a vertical cavity surface emitting laser (VCSEL) substrate 15 houses a VCSEL 16. Most of the infrared laser beam generated by the VCSEL 16 forms an exit beam 17 directed toward the target object, while a portion of the infrared laser beam generated by the VCSEL 16 bounces off the interior of the housing 11 to form a reference beam 18. The reference laser beam 18 reflects from within the exit cavity 12 of the housing 11 to strike a reference array of single photon avalanche diodes (SPADs) 20 embedded in a substrate 19. These reference SPADs 20 detect the arrival of the reference beam 18, thereby establishing a reference time-of-flight value. An optical barrier 14 prevents the exit beam 17 and the reference beam 18 from reaching the input cavity 13.

[0006] The input cavity 13 houses an infrared (IR) notch filter 22 which reduces the amount of ambient light reaching the return array 21. Once through the IR notch filter 22, the return beam 23 strikes the return array 21 of SPADs which are also embedded within the substrate 19.

[0007] The operation of the dTOF sensor 10 involves comparing the time between the reference beam 18 striking the reference array 20 of the SPADs and the time between the outgoing beam 17 reaching the target, reflecting back, passing through the IR notch filter 22, and striking the return array 21 of the SPADs. This time duration is then converted to distance based on the speed of light, which is constant.

[0008] One potential challenge inherent in the operation of time-of-flight calculations is the variability of the response times of both the reference array 20 and the return array 21 of the SPAD. Once an incident photon strikes the SPAD, it triggers the initiation of avalanche breakdown, the generation of an electrical pulse, the detection of that pulse, and finally the propagation of that signal through a readout circuit arrangement, the output of which provides information about the phase difference between the timing reference and the detection from the SPAD. These steps contribute to the response time of the SPAD, with the caveat that the delay caused by the generation and propagation of the timing reference also contributes to the response time.

[0009] However, this response time may be subject to potential variations, which may be caused by process, voltage and / or temperature variations within the SPAD. These fluctuations may unintentionally cause discrepancies in the measured time of flight to the object (and discrepancies in the reference array response time). Note that this potential measurement error may exist even when the distance to the target object remains constant, as this measurement error may exist as an offset, i.e., a fixed error applied to the TOF measurement regardless of the distance to the target. This measurement error or offset may vary with process, voltage or temperature.

[0010] Consider a scenario where the response time of the reference array 20 increases while the response time of the return array 21 remains constant. In this case, even if the actual flight time (from the VCSEL 16 to the object and back to the return array 21) does not change, the differential flight time (between the return array and the reference array) measured by the sensor 10 will decrease due to the increase in the response time of the reference array 20. This can lead to a larger offset. Therefore, this variability in response time risks undermining the accuracy of distance measurements, which is a challenge that needs to be addressed to ensure consistent and reliable performance of the dTOF sensor 10. As such, further development is needed. Summary of the Invention

[0011] This article discloses a time-of-flight (TOF) sensor that integrates a timing reference generator responsible for generating a timing reference signal. The sensor includes a first array and a second array. The first array and the second array each contain multiple arrangements of TOF-related components, each of which is designed to receive the timing reference signal. In addition, both arrays have a dummy arrangement of dummy TOF-related components.

[0012] The signal delivery mechanism for these arrays is structured via two specific pathways. The first pathway facilitates the transmission of timing reference signals to the arrangement of TOF-related components of the first array, passing through the virtual arrangement of TOF-related components of the second array. Conversely, the second pathway channels the timing reference signal to the arrangement of the second array, directing it through the virtual arrangement present in the first array.

[0013] Both arrays include virtual arrangements that provide equal response times across them. Either path may follow a snaking pattern. The first TOF-related component in the first array can be designed as a photodiode-based pixel belonging to a reference array. The second TOF-related component can be constructed as a photodiode-based pixel of a return array, where the return array accommodates a larger number of arrangements than the reference array.

[0014] Each pixel in these arrays may include a readout circuit device. The TOF sensor may include a processing circuit device in the TOF sensor that works in conjunction with the readout circuit device to provide direct or indirect time of flight measurement. The TOF-related components of the first array may be designed as pixels based on single photon avalanche diodes (SPADs), while the components of the second array may be vertical cavity surface emitting laser diodes (VCSELs). Structurally, both arrays may organize their TOF-related components into a row arrangement, with virtual components forming separate rows.

[0015] This article also discloses a method for driving a TOF sensor. The method begins by generating a timing reference signal. This signal is routed through a first path (including a virtual arrangement from a second array) and then directed to the first array. The signal is then conveyed via a second path, moving through the virtual arrangement of the first array, and arriving at the second array.

[0016] A TOF sensor can be used to measure the distance to a specific target. This measurement technique can involve the emission of a laser beam that is split into two different beams: an outgoing beam (reflected from the target back to a second array) and an internal reference beam. The distance to the target is then inferred based on the outputs from the two arrays by tracking the time difference between the detections of the two beams or by observing their phase changes. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a schematic diagram of a prior art time-of-flight sensor.

[0018] Figure 2 is a schematic block diagram of a time-of-flight sensor with a balanced timing reference path as described in this article.

[0019] Figure 2A It shows Figure 2 Schematic block diagram of portions of the clock tree reference path, clock tree return path, driver, reference array, and buffer on the reference array side of FIG.

[0020] Figure 2B It shows Figure 2 Schematic block diagram of portions of the clock tree reference path, clock tree return path, driver, reference array, and buffer on the return array side.

[0021] Figure 3 is a schematic block diagram of another time-of-flight sensor with a balanced timing reference path as described herein.

[0022] Figure 4 is a schematic block diagram of another time-of-flight sensor with a balanced timing reference path as described herein. DETAILED DESCRIPTION

[0023] The following disclosure enables those skilled in the art to make and use the subject matter described herein. The general principles outlined in this disclosure can be applied to embodiments and applications other than those described above without departing from the spirit and scope of the disclosure. It is not intended to limit the disclosure to the embodiments shown, but rather to give it the widest scope consistent with the principles and features disclosed or suggested herein.

[0024] Now refer to Figure 2 Depicted is a time-of-flight (TOF) sensor 100 comprising a reference array 101 and a return array 111. Note that Figure 1 Like the sensor 10, the TOF sensor 100 is housed in a housing and has an optical barrier between the reference array and the return array. Figure 1 The TOF sensor is housed within the housing 11 and can utilize Figure 1 The VCSEL 16 (or any suitable laser generator or LED) emits a laser beam toward a target, where processing circuitry 140 within the sensor 100 is used to determine the distance to the target based on the time of flight of the laser beam to the target.

[0025] In more detail, the reference array 101 includes rows 108(1), ..., 108(m) of pixels 109(1), ..., 109(m). Figure 2A As shown in , each of these pixels 109(1), ..., 109(m) includes at least one single photon avalanche diode (SPAD) 201, which avalanches when struck by an incident photon, effectively converting the photon strike event into an electrical signal that is read out by a readout circuitry 202 within the pixel 109(1), ..., 109(m). In the reference array 101, there are rows 106 of virtual pixels 107, each of which also includes at least one SPAD 201 and associated readout circuitry 202. Figure 2A As shown in , each pixel 109 ( 1 ), . . . , 109 ( m ) and each dummy pixel 107 has a parasitic capacitance C p associated with it, resulting in certain delays that the design attempts to balance.

[0026] Return array 111 includes rows 118(1), ..., 118(n) of pixels 119(1), ..., 109(n). Figure 2B As shown in , each of these pixels 119(1), ..., 119(m) includes at least one single photon avalanche diode (SPAD) 201 that avalanches when struck by an incident photon, effectively converting the photon strike event into an electrical signal that is read out by a readout circuitry 202 within the pixel 119(1), ..., 119(m). The return array 111 also includes rows 116 of virtual pixels 117, each of which also includes at least one SPAD 201 and associated readout circuitry 202. The reference array 101 can, for example, be of the same size as the return array 111 or smaller, and receives a reference beam reflected by the interior of the housing. In some embodiments, the reference array 101 is a multi-dimensional array, for example, having fewer rows and columns of pixels than the return array 111.

[0027] A timing reference signal Tref is generated by a timing generator 130. This timing reference signal Tref serves as a standardized start time according to which photon detection events are measured and is therefore used for time-of-flight calculations.

[0028] In operation, a vertical-cavity surface-emitting laser (VCSEL) (not shown) emits a coherent laser beam in the infrared spectrum, which forms an outgoing beam directed toward a target and a reference beam reflected from the interior of the housing. After reflecting from the target, the outgoing beam becomes a return beam, which is received by return array 111. Simultaneously, the reference beam bounces from the interior of the sensor 100 housing and is received by reference array 101. The time of flight for each path is measured by taking the difference between the captured phase information of return array 111 and the captured phase information of reference array 101. A timing reference signal Tref is used to calculate this time interval—for example, timing reference signal Tref can begin counting when the laser beam is emitted by the VCSEL, and the difference between the count of timing reference signal Tref when the return beam is detected at return array 111 and the count of timing reference signal Tref when the reference beam is detected at reference array 101 can be determined. Since the speed of light is known, the distance to the target can be determined based on this calculated difference.

[0029] It is observed that the timing reference signal Tref is output along the reference path 121 and the return path 122 .

[0030] To reach the rows 108(1), ..., 108(m) of the reference array 101, the timing reference signal Tref traverses a reference path 121 by, on the return array side, passing through a clock tree reference path 112, passing through a driver 114 (e.g., a plurality of inverters INV1-INV4 connected in series), passing through a dummy row 116, and passing through a buffer 115 to reach the reference array side. On the reference array side, the reference path 121 then passes through a clock tree reference path 102, which is used to distribute the timing reference signal Tref to the drivers 104 (e.g., a plurality of inverters INV1-INV4 connected in series). These drivers act as intermediaries between the clock tree 102 of the reference array 101 and the rows 108(1), ..., 108(m) of the pixels 109(1), ..., 109(m). They receive the timing reference signal Tref and forward it directly to the rows 108(1), . . . , 108(m) of pixels 109(1), . . . , 109(m) of the reference array 101.

[0031] Similarly, to reach the rows 118(1), ..., 118(m) of the return array 111, the timing reference signal Tref traverses the return path 122 by: on the reference array side, through the clock tree return path 103, through the driver 104, through the virtual row 106, and through the buffer 105 to reach the return array side. On the return array side, the reference path 122 passes through the clock tree return path 113, which is used to distribute the timing reference signal Tref to the drivers 114. These drivers 114 act as intermediaries between the clock tree 112 of the reference array 111 and the rows 118(1), ..., 118(n) of the pixels 119(1), ..., 119(n). They receive the timing reference signal Tref and forward it directly to the rows 118(1), ..., 118(n) of the pixels 119(1), ..., 119(n) of the return array 111.

[0032] By configuring the sensor 100 so that the timing reference signal Tref (which essentially acts as a standardized starting point for the TOF calculation) traverses both the reference array 101 and the return array 111, a balanced response time is achieved. This is because, regardless of whether the timing reference signal Tref is going to the reference array 101 or the return array 111, it traverses the virtual row 106 or 116 in the opposite array and the appropriate row 108(1), ..., 108(m) or 118(1), ..., 118(n) of SPADs in its corresponding array. This helps ensure that both the reference array 101 and the return array 111 are affected equally by the propagation of the timing reference signal Tref, thereby coordinating their response times.

[0033] This arrangement eliminates the variability that might be introduced if the timing reference signal Tref were to propagate to the reference array 101 and return array 111 via two completely independent paths. Variability can be due to factors such as differences in total wiring length, resistance, capacitance, and other parasitics. These variations can potentially cause differences in the measured flight time, which can lead to undesirable offsets in the distance measurement. However, this dual-path crossover design can eliminate these problems, thereby enhancing the accuracy and reliability of TOF measurements.

[0034] In other words, if a shift in response time is experienced when the timing reference signal Tref passes through a virtual row in one array, the same shift is imparted when the signal passes through the virtual row in the other array. This process effectively cancels out the relative differences in response time between the two arrays. As a result, even if there is a shift in response time, this shift is experienced uniformly by both arrays, ensuring that the difference between the measured flight times remains consistent.

[0035] Furthermore, the paths 121 and 122 taken by the timing reference signal Tref can be modified in the structure of the paths 121 and 122 to accommodate specific response time requirements or to provide such balance. These paths can be direct and utilize blocks with a layout that has fixed parasitics to provide balance, or they can be serpentine through the circuit arrangement, essentially adding additional distance to balance any potential delays in signal propagation due to differences in the circuit layout. Figure 2 An example of this can be observed in , where the return path 122 on the return array side exhibits a serpentine route. This flexibility in the design of the path allows for further fine-tuning of the timing reference signal propagation, thereby providing accurate and consistent TOF calculations under different operating conditions.

[0036] This design of sensor 100 provides a robust solution to the challenges inherent in TOF sensors. By helping to ensure that the response times across reference array 101 and return array 111 are substantially consistent, the accuracy of time-of-flight distance measurements is optimized, making this design particularly beneficial in applications where accurate distance measurement is critical.

[0037] In addition to the advantages already discussed, the design of sensor 100 also helps provide timing accuracy across varying voltages and temperatures. Response time can vary with operating voltage and temperature, potentially leading to discrepancies in time-of-flight measurements. This is because the properties of electronic components vary with temperature and voltage, leading to variations in signal propagation times. However, by routing the timing reference signal Tref through both reference array 101 and return array 111, variations due to voltage or temperature changes will affect both arrays similarly, resulting in a degree of self-compensation.

[0038] Furthermore, the need for fine-tuning range offsets during testing is also reduced. Fine-tuning range offsets during testing is a time-consuming and expensive process that involves calibrating the sensor at multiple points to account for variability in component properties. This calibration process is intended to correct for inaccuracies in time-of-flight measurements. However, by providing consistent response times across both reference array 101 and return array 111, the design of sensor 100 inherently minimizes these range offsets. Consequently, the need for fine-tuning range offsets during testing is reduced, thereby reducing testing cost and complexity. This not only reduces manufacturing expenses but also makes the sensor easier to adopt across different applications due to the reduced calibration requirements.

[0039] For example, in a design of sensor 100, the timing reference signal passes through two arrays (e.g., all arrays of the sensor) with more than two reference and return arrays. In scenarios employing multiple spatial illuminations, using multiple reference and return arrays can help capture more comprehensive data, thereby resulting in more accurate and detailed measurements. By passing the timing reference signal through each reference array and each return array, consistent timing can be maintained.

[0040] Furthermore, by allowing the path of the timing reference signal to be directed or snaking through different reference and return arrays to balance delays, the design can also accommodate the different paths that light may take when using multiple spatial illuminations. This improves timing accuracy and reliability under more complex operating conditions, thereby reducing the need for range offset fine-tuning during testing and improving the performance of advanced dTOF systems with multiple spatial illuminations.

[0041] Although the sensor 100 has been described in the context of direct time-of-flight (dTOF) operation, the routing of the timing reference signal Tref as described above is also applicable to indirect time-of-flight (iTOF) designs.

[0042] In the same way as dTOF sensing, iTOF sensing compares the arrival time of light observed by a photodetector (typically a fast photodiode rather than a SPAD) to a timing reference. Therefore, iTOF technology is subject to the same offset as dTOF technology. Therefore, iTOF designs can also benefit from using a reference array in the same way as dTOF designs, and therefore can also benefit from the same timing compensation schemes described above for dTOF.

[0043] In an iTOF design that includes both a reference array and a return array, the role of the timing reference signal is slightly different from that in a dTOF system, but is also interesting. Instead of measuring the time it takes for a short pulse of light to travel to the target and back, the iTOF system emits a continuous wave of modulated light and measures the phase shift between the emitted wave and the reflected wave. This involves accurate modulation and timing accuracy of the demodulation of the optical signal. The design of the sensor 100, in which the timing reference signal Tref passes through both the reference array 101 and the return array 111, helps synchronize the modulation and demodulation processes. By maintaining consistent and precise timing across the array, the phase shift can be accurately determined, resulting in more reliable distance measurements. Like in a dTOF design, the architecture of the sensor 100 provides timing accuracy under varying voltages and temperatures and reduces the need for range offset fine-tuning during testing, thereby improving the performance and cost-effectiveness of the iTOF system.

[0044] Reference now Figure 3In another embodiment described, sensor design 100' includes return array 111 and its associated circuitry while eliminating reference array 101 and its associated circuitry. Instead, the design utilizes virtual paths within VCSEL array 131, as described below.

[0045] In operation, the timing reference signal Tref passes along path 121, continuing through the dummy row 116 within the return array 111. After traversing the dummy row, it is then routed through a designated clock tree VCSEL path 132. Along this path, the timing reference signal Tref reaches a gate driver 137 housed within the driver section 134. This gate driver 137 is responsible for controlling the gate of a transistor T within the VCSEL array 131. Transistor T is, in turn, connected to a VCSEL D1, which has its anode connected to a positive voltage supply (VDD), its cathode connected to the drain of transistor T, and its source connected to ground.

[0046] The driver section 134 includes a dummy gate drive circuitry 136. This circuitry is designed to mimic the delay through the gate driver 137. In parallel with the process used to drive the VCSEL, the timing reference signal Tref is routed along path 123, through the clock tree return path 133, and into the dummy gate drive circuitry 136. After this point, the timing reference signal Tref is routed back to the clock tree return path 113, where it passes into the driver 114 and then ultimately into the rows 118(1), ..., 118(n) of the return array 111.

[0047] This configuration provides that the timing reference signal Tref traverses the return array, specifically the virtual row 116 of SPADs, before being used to drive the VCSELs that emit the laser beam. The timing reference signal Tref also passes through the VCSEL array 131 before being passed to the return array 111. By having the timing reference signal Tref traverse the VCSEL array before reaching the return array 116, the timing of the photon emissions from the VCSELs can be accurately captured. This is useful because the time of these emissions is the starting point for the TOF measurement. Delays or variability in capturing this starting time directly impact the accuracy of the TOF and the overall performance of the sensor 100'.

[0048] Obviously, modifications and variations can be made to what has been described and illustrated herein without departing from the scope of the present disclosure. In fact, the principles disclosed herein are applicable to any TOF sensor. Figure 4A general embodiment illustrating this is described. This embodiment retains the timing reference generator 130, which generates the timing reference signal Tref, and the paths 121 and 123. In this embodiment, there are two arrays of TOF related components - a first array 201 and a second array 211.

[0049] The first array 201 includes m rows 208(1), ..., 208(m) of first TOF-related components. In addition, the first array 201 includes a virtual row 206 of components. Similarly, the second array 211 includes n rows 218(1), ..., 218(n) of second TOF-related components, as well as a virtual row 216 of components.

[0050] The path of the timing reference signal Tref to the component rows 218(1), ..., 218(n) of the second array 211 traverses along path 123. On its way, it passes through the dummy component row 206 of the first array 201. After that, it loops back to the component rows 218(1), ..., 218(n) in the second array 211.

[0051] Similarly, to reach the component rows 208(1), ..., 208(m) of the first array 201, the timing reference signal Tref moves along the path 121. It passes through the virtual component row 216 in the second array 211 and then snakes back to reach the component rows 208(1), ..., 208(m) in the first array 201.

[0052] This generalized embodiment illustrates that the concept of uniformly distributed response times introduced herein is applicable to any two arrays of TOF-related components, not just SPAD or VCSEL arrays. This uniform response time, due to the timing reference signal Tref passing through both the first array 201 and the second array 211, enables balanced delays to be achieved across the two arrays by accounting for any inherent variability in the response times of the array's components. This ultimately results in a more accurate and reliable TOF sensor system that is versatile and suitable for a wide range of applications.

[0053] Although the present disclosure has been described using a limited number of embodiments, those skilled in the art, after having the benefit of this disclosure, may envision other embodiments that do not depart from the scope of the disclosure—for example, pixels may be arranged in columns, trees, or any other suitable arrangement rather than rows. Furthermore, those skilled in the art may envision embodiments that represent various combinations of the embodiments disclosed herein in various ways.

Claims

1. A time-of-flight TOF sensor, comprising: a timing reference generator configured to generate a timing reference signal; a first array of first TOF-related components, the first array comprising a plurality of arrangements of TOF-related components, wherein each arrangement receives the timing reference signal, and a virtual arrangement of virtual TOF-related components; a second array of second TOF-related components, the second array comprising a plurality of arrangements of TOF-related components, wherein each arrangement receives the timing reference signal, and a virtual arrangement of virtual TOF-related components; a first path configured to deliver the timing reference signal to the plurality of arrangements of the first array, the first path starting from the timing reference generator through the virtual arrangements of the virtual TOF-related components in the second array to the first array of the first TOF-related components; as well as A second path, the second path is configured to deliver the timing reference signal to the plurality of arrangements of the second array, the second path starting from the timing reference generator, passing through the virtual arrangements of the virtual TOF-related components in the first array, and reaching the second array of the first TOF-related components.

2. The sensor of claim 1 , wherein the first array and the second array have substantially identical response times due to the timing reference signal traversing through the virtual arrangement of the virtual TOF-related components in the first array and the virtual arrangement of the virtual TOF-related components in the second array. 3 . The sensor of claim 1 , wherein at least one of the first path and the second path follows a serpentine route.

4. The sensor of claim 1 , wherein the first TOF-related component is a photodiode-based pixel of a reference array; and wherein the first TOF-related component is a photodiode-based pixel of a return array, wherein the return array has an arrangement of more TOF-related components than the reference array.

5. A sensor according to claim 4, wherein each photodiode-based pixel of the reference array includes a readout circuit device; wherein each photodiode-based pixel of the return array includes a readout circuit device; and wherein the TOF sensor includes a processing circuit device, which cooperates with the readout circuit devices of the photodiode-based pixels of the reference array and the readout circuit devices of the photodiode-based pixels of the return array to perform direct time-of-flight testing.

6. A sensor according to claim 4, wherein each photodiode-based pixel of the reference array includes a readout circuit device; wherein each photodiode-based pixel of the return array includes a readout circuit device; and wherein the TOF sensor includes a processing circuit device, which cooperates with the readout circuit devices of the photodiode-based pixels of the reference array and the readout circuit devices of the photodiode-based pixels of the return array to perform an indirect time-of-flight test.

7. A sensor according to claim 4, wherein the first TOF-related component is a single-photon avalanche diode (SPAD)-based pixel of a reference array; and wherein the first TOF-related component is a SPAD-based pixel of a return array, wherein the return array has an arrangement of more TOF-related components than the reference array.

8. The sensor of claim 1, wherein the first TOF-related component is a photodiode of a reference array; and wherein the second TOF-related component is a light source.

9. The sensor of claim 8, wherein the first TOF-related component is a single photon avalanche diode (SPAD) of a reference array; and wherein the second TOF-related component is a vertical cavity surface emitting laser diode (VCSEL).

10. A sensor according to claim 1, wherein the multiple arrangements of the TOF-related components of the first array include multiple rows of TOF-related components; wherein the virtual arrangement of the virtual TOF-related components of the first array includes virtual rows of TOF-related components; wherein the multiple arrangements of the TOF-related components of the second array include multiple rows of TOF-related components; wherein the virtual arrangement of the virtual TOF-related components of the second array includes virtual rows of TOF-related components.

11. A method for operating a time-of-flight (TOF) sensor, the method comprising: generating a timing reference signal; passing the timing reference signal through a first path, the first path comprising a virtual arrangement within a second array of second TOF-related components; delivering the timing reference signal to a first array of first TOF-related components after the timing reference signal passes through the first path; passing the timing reference signal through a second path, the second path comprising a virtual arrangement of the first array; as well as After the timing reference signal passes through the second path, the timing reference signal is delivered to the second array.

12. The method according to claim 11, further comprising: The TOF sensor is used to measure the distance to the target.

13. The method of claim 11, wherein the distance to the target is measured by: generating a laser beam using at least one light source; splitting the laser beam into: an outgoing beam directed toward the target such that the outgoing beam reflects from the target to return as a return beam to the second array of the second TOF-related component, the second TOF-related component being a photodiode-based pixel; and a reference beam that reflects from an interior of the TOF sensor to return to the first array of the first TOF-related components, the first TOF-related components being photodiode-based pixels; as well as The distance to the target is determined based on outputs from the first array and the second array.

14. The method of claim 13, wherein the distance to the target is determined based on outputs from the first array and the second array by measuring the elapsed time between detection of the reference beam by the first array and detection of the return beam by the second array.

15. The method of claim 13, wherein the distance to the target is determined based on outputs from the first array and the second array by measuring a phase difference between the reference beam detected by the first array and the return beam detected by the second array.

16. The method of claim 11, wherein the distance to the target is measured by: generating a laser beam using at least one vertical cavity surface emitting laser diode (VSEL); Splitting the laser beam into: an outgoing beam directed toward the target so that the outgoing beam is reflected from the target to return as a return beam to the second array of the second TOF-related component, the second TOF-related component being a pixel based on a single photon avalanche diode (SPAD); and a reference beam that reflects from an interior of the TOF sensor to return to the first array of the first TOF-related components, the first TOF-related components being SPAD-based pixels; as well as The distance to the target is determined based on outputs from the first array and the second array.

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