Optical scanning multiplexing apparatus and method

Abstract

Systems and apparatus for correcting periodic signals include receiving indexed light detection data from an optical scanner; determining a bias error for a movable mirror in the optical scanner based on the indexed light detection data; determining a phase shift error of the movable mirror based on the indexed light detection data; and determining an amplitude error of the movable mirror based on the indexed light detection data.

Description

[0001] Related Applications

[0002] This application claims priority to U.S. patent application No. 18 / 185,012, filed on March 16, 2023, and claims the benefit of U.S. Provisional Application No. 63 / 269,557, filed on March 18, 2022, entitled “Optical Scanning Multiplexing Apparatus and Method,” the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present disclosure relates to an optical scanning system. For example, the scanning system includes a light source that provides light, a mirror, and a light detector that detects light reflected from the mirror. Background Art

[0004] Figure 1A The operating principle of the optical scanner 102 is shown. Figure 1A As shown, the optical scanner 102 includes a movable mirror 110 (eg, an oscillating mirror, a rotating mirror), a photodetector unit 112, and a light source unit 114. Figure 1A As shown, the light source unit 114 includes an array 122 (e.g., an array having M rows and N columns) of light sources 116. The light detector unit 112 includes M light detectors 124. In other words, each light detector 124 of the light detector unit 112 corresponds to a single row of the light source array 122.

[0005] As shown, the movable mirror 110 is positioned to receive light from the light source unit 114, and the light detector unit 112 is positioned to detect light reflected or redirected from the movable mirror 110. As shown, an electromechanical device 111 (e.g., a motor, a stepper motor, a servo motor) is provided to enable the movable mirror 110 to oscillate.

[0006] like Figure 1B and Figure 1C As shown, as the angle of the movable mirror 110 changes in response to the movable mirror 110 oscillating or rotating about an axis (i.e., movement of the movable mirror), light from different light sources 116 is received by the movable mirror 110 onto the light detector unit 112. Figure 1B As shown, the movable mirror 110 (in this example, the instantaneous angle θ of the movable mirror 110 is 0°) is positioned to reflect or redirect light from the light source 116x onto the light detector unit 112 (e.g., the light detector 124 of the light detector unit 112). Figure 1C As shown, the movable mirror 110 (in this example, the instantaneous angle θ of the movable mirror 110 is x°) is in different positions, and the movable mirror 110 is positioned to reflect or redirect light from the light source 116y onto the light detector unit 112 (e.g., the light detector 124 of the light detector unit 112).

[0007] The photodetector unit 112 generates an output signal (e.g., an analog signal) based on the light (e.g., the intensity of the light) detected or received from the movable mirror 110. The generated analog signal is then digitized and further processed by a suitable processor (not shown) in communication with the photodetector unit 112.

[0008] As will be appreciated by those skilled in the art, the nature of processing the analog signal may vary between simple processing to highly complex processing, depending on the application.

[0009] The instantaneous angle θ of the movable mirror 110 (also referred to as a scanning mirror) may be controlled using a signal or current based on a function set to the electromechanical device 111. For example, the instantaneous angle θ is determined by:

[0010] θ(t)=k×I(t) (Formula 1)

[0011] Wherein, θ(t) is the instantaneous angle of the movable mirror 110 at time t, I(t) is the variable current or signal provided at time t (e.g., the variable current or signal that drives the electromechanical device 111), and k (also called the amplitude or scanning amplitude) is a proportionality constant (this constant may vary between optical scanner manufacturers or different optical scanners). To improve the efficiency of the scanning operation, the scanning system can combine multiple optical scanners.

[0012] What is needed is a method, apparatus and system for controlling multiple optical scanners with a single set of electronic devices, for correcting bias errors in the scanning mirror of each optical scanner in the optical scanners, for compensating for the phase response of the scanning mirror of each optical scanner in the optical scanners, and / or for adjusting the proportionality constant k. Summary of the invention

[0013] Disclosed are methods, apparatus, and systems for controlling multiple optical scanners with a single set of electronics, for correcting bias errors in the scanning mirrors of each of the optical scanners, for compensating for the phase response of the scanning mirrors of each of the optical scanners, and / or for adjusting a proportionality constant k. In the present disclosure, an index light source (e.g., a row of index light sources) provides or emits a constant light for tracking or monitoring the movement of the scanning mirrors. Based on an analysis of the movement of the scanning mirrors, the system is able to correct bias errors in the scanning mirrors of each optical scanner to compensate for the phase response of the scanning mirrors of each optical scanner, and / or adjust the proportionality constant k.

[0014] Aspects of the present disclosure provide a method for correcting a periodic signal. The method includes receiving index light detection data from an optical scanner at one or more processors. The method also includes determining, by the one or more processors, a bias error of a movable mirror of the optical scanner based on the index light detection data. The method also includes determining, by the one or more processors, a phase shift error of a movable mirror of the optical scanner based on the index light detection data. The method also includes determining, by the one or more processors, an amplitude error of the movable mirror of the optical scanner based on the index light detection data.

[0015] Implementations of the present disclosure may include one or more of the following optional features: Determining an amplitude error of the movable mirror may include determining a time interval between two consecutive pulses generated by the right index light in the index light detection data. In response to determining that there is an amplitude error, the method may include adjusting, by one or more processors, the amplitude of a function used to generate a signal to drive the movable mirror. Determining a phase shift error of the movable mirror may include determining a time interval between a first time when an intermediate index pulse is generated by detecting the intermediate index light and a second time when the intermediate index pulse is expected to be generated. In response to determining that there is a phase shift error, the method may include adding, by one or more processors, a cancelling phase shift to the function used to generate a signal to drive the movable mirror. Determining a bias error of the movable mirror may include determining a first time interval between two consecutive pulses generated by the right index light in the index light detection data, and determining a second time interval between two consecutive pulses generated by the left index light in the index light detection data. In response to determining that there is a bias error, the method may include adding, by one or more processors, a cancelling bias to the function used to generate a signal to drive the movable mirror.

[0016] Another aspect of the present disclosure provides a system that can be configured to include data processing hardware (one or more processors) and memory hardware that communicates with the data processing hardware. The memory hardware can be configured to store instructions that, when executed on the data processing hardware, cause the data processing hardware to perform operations. The operations performed include, for example, one or more of the following: receiving index light detection data from an optical scanner; determining a bias error of a movable mirror of the optical scanner based on the index light detection data; determining a phase shift error of the movable mirror of the optical scanner based on the index light detection data; and / or determining an amplitude error of the movable mirror of the optical scanner based on the index light detection data.

[0017] Implementations of the present disclosure may include one or more of the following optional features: Determining an amplitude error of the movable mirror may include determining a time interval between two consecutive pulses generated by the right index light in the index light detection data. In response to determining that there is an amplitude error, the operation may include adjusting the amplitude of a function used to generate a signal to drive the movable mirror. Determining a phase shift error of the movable mirror may include determining a time interval between a first time when an intermediate index pulse is generated by detecting the intermediate index light and a second time when the intermediate index pulse is expected to be generated. In response to determining that there is a phase shift error, the operation may include adding a counteracting phase shift to the function used to generate a signal to drive the movable mirror. Determining a bias error of the movable mirror may include determining a first time interval between two consecutive pulses generated by the right index light in the index light detection data, and determining a second time interval between two consecutive pulses generated by the left index light in the index light detection data. In response to determining that there is a bias error, the operation may include adding a counteracting bias to the function used to generate a signal to drive the movable mirror.

[0018] Another aspect of the present disclosure provides a scanning system. The scanning system may be configured to include a drive function generator, which may be configured to generate a plurality of periodic signals. The plurality of periodic signals may include, for example, at least a first periodic signal and a second periodic signal. The system may also be configured to include a plurality of optical scanners. The plurality of optical scanners may include, for example, a first optical scanner and a second optical scanner. The system may also be configured to include a first mirror of the first optical scanner and a second mirror of the second optical scanner. The first mirror oscillates based on the first periodic signal and the second mirror oscillates based on the second periodic signal. The first periodic signal has a first phase shift and the second periodic signal has a second phase shift different from the first phase shift.

[0019] Implementations of the present disclosure may include one or more of the following optional features: The first phase shift may be 0, and the second phase shift may be 1 / 4 period of the second periodic signal. The drive function generator may generate the first periodic signal based on the first sine function using the first phase shift. The drive function generator may generate the second periodic signal based on the first sine function using the second phase shift. The first phase shift may be 0, and the second phase shift may be 1 / 4 period of the first sine function.

[0020] The first optical scanner may include a light source device including a light source array, a first index light source, a second index light source, and a third index light source. The first index light source may be aligned with a first column of the light source array, and the second index light source may be aligned with a last column of the light source array. The third index light source may be aligned with a center line between the first column of the light source array and the last column of the light source array. In some cases, the third index light source may be aligned with a middle column of the light source array. The first optical scanner may include a light detection unit including a light detector and an index light detector corresponding to a row of the light source array, the index light detector being arranged to detect index light from the first index light source, the second index light source, and the third index light source. The system may include a scan data processor that may be configured to receive scan data from a plurality of optical scanners.

[0021] As required, both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosed embodiments.

[0022] References

[0023] All publications, patents, and patent applications mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication, patent, or patent application was specifically and individually indicated to be incorporated by reference.

[0024] US 5,557,444 A issued to Melville et al. on September 17, 1996;

[0025] US 5,956,355 A issued to Swanson et al. on September 21, 1999;

[0026] US 6,396,561 B1 issued May 28, 2002 to Vernackt et al.;

[0027] US 7,485,485 B2 issued on February 3, 2009 to Linden et al.;

[0028] US 8,294,454 B2 granted to Siraky on October 23, 2012;

[0029] US 8,427,657 B2 granted to Milanovi on April 23, 2013;

[0030] US 8,649,079 B2 granted to Naono on February 11, 2014;

[0031] US 9,122,061 B2 to Azuma, granted on September 1, 2015;

[0032] US 9,874,434 B2 to Holzapfel on January 23, 2018;

[0033] US10,571,552B1 granted to Gao et al. on February 25, 2020;

[0034] US11,112,491B2 granted to Abediasl et al. on September 7, 2021;

[0035] US2004 / 0095623 A1 published by Barresi et al. on May 20, 2004;

[0036] US2020 / 0319450 A1 published by Druml et al. on October 8, 2020;

[0037] US2021 / 0011133 A1 published by Morrority et al. on January 14, 2021;

[0038] RIZA, et al., I-WMOSS: Interferometric Wavelength Multiplexed OpticalScanning Sensor, IEEE, International Symposium on Optomechatronic Technologies, ISOT (October 2012); and

[0039] RIZA, MOST: Multiplexed Optical Scanner Technology, IEEE Lasers and Electro-Optics Society 2000 Annual Meeting (November 2000). BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The novel features of the present invention are particularly set forth in the appended claims. A better understanding of the features and advantages of the present invention will be obtained by reference to the following detailed description which sets forth illustrative embodiments utilizing the principles of the present invention, and in the accompanying drawings:

[0041] Figures 1A to 1C The principle of operation of an optical scanner is shown;

[0042] FIG. 2A to FIG. 2CAn example optical scanner according to some embodiments of the present disclosure is shown, the optical scanner comprising: a light source unit including an array of light sources and a row of index light sources; a light detector unit configured to detect light from the array of light sources and index light from the row of index light sources; and a movable mirror;

[0043] Figure 3 shows a first amplitude of a first periodic function comprising a range between a positive instantaneous angle and a negative instantaneous angle over time according to some embodiments of the present disclosure;

[0044] Figure 4 shows a first amplitude of a first periodic function and a second amplitude of a second periodic function, their respective amplitudes encompassing a range between a positive instantaneous angle and a negative instantaneous angle over time, according to some embodiments of the present disclosure;

[0045] Figure 5A and Figure 5B shows a block diagram of an example scanning system configured with multiple optical scanners according to some embodiments of the present disclosure;

[0046] Fig. 6A and Figure 6B shows a block diagram of an example scanning system including a first optical scanner and a second optical scanner according to some embodiments of the present disclosure;

[0047] Figure 6C showing a first periodic signal of a first movable mirror of a first optical scanner and a second periodic signal of a second movable mirror of a second optical scanner according to some embodiments of the present disclosure;

[0048] Fig.6D shows index light detection data including pulse signals from detecting right index light, left index light, and middle index light according to some embodiments of the present invention; and

[0049] Fig. 6E Index light detection data including a pulse signal from detecting intermediate index light according to some embodiments of the present invention is shown.

[0050] Figure 7 A flow chart of an example method of controlling a scanning system configured with multiple optical scanners is shown.

[0051] The same reference symbols in different drawings denote the same elements. DETAILED DESCRIPTION

[0052] Figure 2A A diagram of an example optical scanner 202 configured with a movable mirror 210 (eg, an oscillating mirror) is shown in accordance with some embodiments of the present disclosure. Figure 2B Shown include Figure 2A 2 is a plan view of an example light source unit 214 of a light source array 222 in FIG. Figure 2C Shows Figure 2A FIG. 2 is a plan view of an example light detection unit 212 in FIG. Figure 2A and Figure 2B As shown, the light source unit 214 includes a first light source 2161 arranged along a first column of the array 222 and a fifth light source 2165 arranged along a fifth column (in this example, the last column) of the array 222 .

[0053] like Figure 2A and Figure 2B As shown, the example optical scanner 202 includes a light source unit 214 including a plurality of light sources 216. 1-15 and a plurality of index light sources (e.g., a first index light source 218, a second index light source 219, and a third index light source 220). In this example, the index light sources 218, 219, and 220 provide or emit constant light because the light from the index light sources 218, 219, and 220 is used to track or monitor the movement of the movable mirror 210. The light source 216 1-15 The index light sources 218, 219, and 220 may be optical fiber terminals or tip-emitting light generated by a light generator such as a laser generator (not shown). However, the present disclosure does not refer to the light source 216 as 1-15 and index light sources 218, 219, and 220 are limited to the optical fiber tip. 1-15 The index light sources 218 , 219 , and 220 may include light emitting devices or suitable devices that can provide light to the movable mirror 110 .

[0054] As shown in the figure, in this example, the plurality of light sources 216 of the light source unit 214 1-15 A 3 (row) x 5 (column) array 222 is formed. A first index light source 218 (also referred to as a left index light) is shown arranged along the first column of array 222, a second index light source 219 (also referred to as a middle index light) is shown arranged along the third column (also referred to as the middle column) of array 222, and a third index light source 220 (also referred to as a right index light) is shown arranged along the fifth column of array 222. In other words, left index light 218 is aligned with the leftmost column of array 222, middle index light 219 is aligned with the middle column of array 222, and right index light 220 is aligned with the rightmost column of array 222. In some cases, middle index light 219 is aligned with a center line between left index light 218 and right index light 220. As shown, light source 216 1-15 Each light source in is spaced apart from each other. Figure 2BIn the example, the example light source unit 214 has an array 222 with three rows and five columns. However, the present disclosure does not limit the number of rows and columns in the array 222 to the number of rows and columns shown in the example. For example, the array 222 of the light source unit 214 can include up to 384 light sources 216 (e.g., an array 222 with 16 rows and 24 columns).

[0055] like Figure 2A and Figure 2C As shown, the example optical scanner 202 includes a light detector unit 212 including a plurality of light detectors 224. 1-3 and indexing light detector 226. The light detector unit 212 may be configured to include Figure 2B The light source 216 in the first row of the array 222 1-5 The corresponding first light detector 2241 and Figure 2B The light source 216 in the second row of the array 222 6-10 The corresponding second light detector 2242 and Figure 2B The light source 216 in the third row of the array 222 11-15 As shown in the figure, the light detection unit 212 includes an index light detector 226 corresponding to the index light source 218, the index light source 219, and the index light source 220. The light detector 224 1-3 The index light detector 226 is a fiber optic terminal or tip configured to receive light from the light source unit 214. 1-3 The received light may be directed to a light / index light detection device 508 / 608 (e.g., a light detection circuit), which may be configured to convert the light into an electrical signal (e.g., convert the light into an analog signal). Additionally, the index light received by the index light detector 226 may be directed to a light / index light detection device 508 / 608, which may also be configured to convert the light into an electrical signal (e.g., convert the index light into a pulse signal).

[0056] Additional details regarding the light / index light detection device 508 / 608 are described elsewhere in this disclosure. Figure 2B and Figure 2C As shown, the number of light detectors 224 in the light detection unit 212 corresponds to the number of rows in the array 222. For example, when the light source unit 214 includes an array 222 having 16 rows and 24 columns, the light detector unit 212 includes 16 light detectors 224 and 1 index light detector 226.

[0057] like Figure 2AAs shown, an electromechanical device 211 (e.g., a motor, a stepper motor, a servo motor) can be coupled to the movable mirror 210, and the electromechanical device 211 can move or oscillate the movable mirror 210. When the angle of the movable mirror 210 changes in response to the movable mirror 210 oscillating or rotating about the axis, different columns of light from the light source 216 are received on the light detector unit 212 through the movable mirror 210. Figure 2A The movable mirror 210 (eg, an oscillating mirror) in the embodiment is positioned to reflect or redirect light from the third light source 2163. The movable mirror 210 also directs light from the eighth light source 2168 and the thirteenth light source 216 13 and the second index light source 219 (i.e., the light source / index light source in the middle column) ( Figure 2B ) are reflected or redirected to Figure 2C The first light detector 2241, the second light detector 2242, and the third light detector 2243 shown in FIG. Figure 2C When the movable mirror 210 rotates in a first direction (e.g., clockwise), the movable mirror 210 (e.g., an oscillating mirror) is positioned to direct the light from the fourth light source 2164, the ninth light source 2169, and the fourteenth light source 216 14 The light is reflected or redirected to the first light detector 2241, the second light detector 2242, and the third light detector 2243 respectively.

[0058] When the movable mirror 210 continues to rotate in the first direction (eg, clockwise), the movable mirror 210 (eg, an oscillating mirror) transmits the light from the fifth light source 2165, the tenth light source 216 10 、15th light source 216 15 The light from the first light detector 2241, the second light detector 2242, the third light detector 2243 and the index light detector 226 are respectively reflected or redirected to the first light detector 2241, the second light detector 2242, the third light detector 2243 and the index light detector 226.

[0059] When the movable mirror 210 changes from a rotation in the first direction to a rotation in the second direction (eg, counterclockwise), the movable mirror 210 (eg, an oscillating mirror) returns to the previous position to reflect or redirect the light from the fifth light source 2165, the tenth light source 216 10 、15th light source 216 15 and the third index light source 220 (i.e., the light source / index light source in the rightmost column) to the first light detector 2241, the second light detector 2242, the third light detector 2243, and the index light detector 226. When the movable mirror 210 continues to rotate in the second direction (e.g., counterclockwise), the movable mirror 210 (e.g., the oscillating mirror) transmits the fourth light source 2164, the ninth light source 2169, and the fourteenth light source 21614 The light is reflected or redirected to the first light detector 2241, the second light detector 2242, and the third light detector 2243 respectively.

[0060] When the movable mirror 210 continues to rotate to the second direction (eg, counterclockwise), the movable mirror 210 (eg, an oscillating mirror) is positioned to transmit the light from the third light source 2163, the eighth light source 2168, the thirteenth light source 216 13 The light from the second light source 2162, the seventh light source 2167, and the twelfth light source 2164 are reflected or redirected to the first light detector 2241, the second light detector 2242, the third light detector 2243, and the index light detector 226, respectively. Continued rotation in the second direction (e.g., counterclockwise) enables the movable mirror 210 (e.g., oscillating mirror) to direct the light from the second light source 2162, the seventh light source 2167, and the twelfth light source 2164 to the first light detector 2241, the second light detector 2242, the third light detector 2243, and the index light detector 226, respectively. 12 The light from the first light source 2161, the sixth light source 216, the eleventh light source 216 is reflected or redirected to the first light detector 2241, the second light detector 2242 and the third light detector 2243 respectively until the movable mirror can transmit the light from the first light source 2161, the sixth light source 216, the eleventh light source 216 11 , the light from the first index light source 218 (ie, the light source / index light source in the leftmost column) is reflected or redirected to the first light detector 2241, the second light detector 2242, the third light detector 2243 and the index light detector 226, respectively.

[0061] Once the movable mirror 210 reaches the end of the rotation path in the second direction, the movable mirror 210 changes the rotation direction to the first direction, at which time the movable mirror 210 (e.g., an oscillating mirror) returns to the previous position to transmit the light from the first light source 2161, the sixth light source 2166, the eleventh light source 216 11 The light from the first indexing light source 218 is reflected or redirected onto the first light detector 2241, the second light detector 2242, the third light detector 2243 and the indexing light detector 226, respectively. Therefore, the movable mirror 210 has a rotation path that enables the movable mirror to move through a range of motion around the axis of the rotation path. Once the movable mirror 210 reaches the first end of the rotation path, the movable mirror 210 reverses direction around the axis and rotates to the second end of the rotation path. During rotation, the movable mirror 210 affects the mapping of the light source columns to the array 222. Thus, the selection of the light source columns in the light source array 222 is a function of the tilt angle of the movable mirror 210. Because the tilt angle is periodic in time, the resulting mapping will also be periodic.

[0062] Figure 3An example periodic function 300 including a range between a positive instantaneous angle θ (+θ0) and a negative instantaneous angle θ (-θ0) according to some embodiments of the present disclosure is shown. The instantaneous angle is also referred to as a deflection angle or a scan angle. In this example, the range between +θ0 and -θ0 can correspond to a scan of the source array 222 from the leftmost column of the array 222 to the rightmost column of the array 222. The instantaneous angle θ of the movable mirror 210 (e.g., the scan angle of the movable mirror 210) oscillates between +θ0. In other words, θ() = θ(T1), where T1 = 1 / 8·period = 45 degrees.

[0063] like Figure 3 As shown, the instantaneous angle θ of the movable mirror 210 changes with time t. When the movable mirror 210 is in a horizontal position, the instantaneous angle θ of the movable mirror 210 is 0°. Therefore, the movable mirror 210 is positioned to reflect light from the light source unit 214 (e.g., light from the light source / index light source in the middle column) onto the light detector unit 212. The period shown has 45 degrees.

[0064] As discussed above, the movable mirror 210 can be configured for oscillation or rotation. During the first portion T1 of the period T (e.g., 1 / 8 period T), the instantaneous angle θ of the movable mirror 210 changes from 0° to +θ0 (in this example, +θ0=20°). Therefore, the movable mirror 210 is positioned to reflect light from the light source unit 214 (e.g., light from the light source / index light source in the rightmost column) onto the light detection unit 212. As shown, the instantaneous angle θ of the movable mirror 210 remains at θ0 during the second portion T2 of the period T (e.g., 1 / 4 or 2 / 8 period T), changes from θ0 to 0° during the third portion T3 of the period T (e.g., 1 / 8 period T), and changes from 0° to -θ0 (in this example, -θ0=-20°) during the fourth portion T4 of the period T (e.g., 1 / 8 period T). Therefore, the movable mirror 210 is positioned to reflect light from the light source unit 214 (e.g., light from the light source / index light source in the leftmost column) onto the light detector unit 212. As shown, the instantaneous angle θ of the movable mirror 210 remains at -θ0 during the fifth portion T5 of the period T (e.g., 1 / 4 or 2 / 8 period T), and changes from -θ0 (e.g., -20°) to 0° during the sixth portion T6 of the period T (e.g., 1 / 8 period T).

[0065] Figure 4 Some embodiments of the present disclosure are shown Figure 30 (“first periodic function”) and another example periodic function 400 (“second periodic function”) included in the range between the positive instantaneous angle θ (+θ0) and the negative instantaneous angle θ (-θ0). In this example, the first movable mirror 2101 of the first optical scanner 2021 rotates or oscillates based on the first periodic function 300, and the second movable mirror 2102 of the second optical scanner 2022 rotates or oscillates based on the second periodic function 400. The second movable mirror 2102 of the second optical scanner 2022 oscillates or rotates based on the same periodic function that drives the first movable mirror 2101. However, as shown in the figure, the phase of the second periodic function 400 is offset by 1 / 4 period T.

[0066] Now turn to Figure 5A , Figure 5A The configuration includes a drive function generator 504, a plurality of optical scanners 202 1...N , an optical combiner 506, a light / index light detection device 508, and an error signal generator 501. Each optical scanner 202 includes a light detector unit 212, a light source unit 214, a movable mirror 210 (e.g., an oscillating mirror), and the movable mirror is configured to oscillate based on a corresponding periodic signal 514 (e.g., a signal based on a sine function, a signal based on a cosine function) from a drive function generator 504. In this example, the drive function generator 504 generates a periodic signal 514 with different phase shifts. Therefore, each movable mirror 210 oscillates based on a periodic signal 514 with different phases. For example, the drive function generator 504 provides a first periodic signal 5141 to the first optical scanner 2021 based on a sine function with a first phase shift (in this example, a 0 phase shift), and provides a second periodic signal 5142 to the second optical scanner 2022 based on a sine function with a second phase shift (in this example, a 1 / 4 phase shift period).

[0067] In addition, each optical scanner (eg, the first optical scanner 2021 to the optical scanner 202 N collectively referred to as optical scanner 202 1...N ) is connected to the optical combiner 506 (eg, via an optical fiber). Thus, in this example, the optical scanner 202 1...N Each optical scanner is configured to include a light detector 224 1-3 and the optical information or optical signal 516 of the light / index light detected by the index light detector 226 1-N is transmitted to the optical combiner 506. Therefore, the optical combiner 506 converts the optical signal 516 1-NThe light detected by the first light detector 2241 of the first optical scanner 2021, the light detected by the first light detector 2241 of the second optical scanner 2022, and the light detected by the Nth optical scanner 202 N The light detected by the first light detector 2241 of the first optical scanner 2021 is combined at the optical combiner 506 (forming a first combined light signal 5181). Similarly, the light detected by the second light detector 2242 of the first optical scanner 2021, the light detected by the second light detector 2242 of the second optical scanner 2022, and the light detected by the Nth optical scanner 202 N The light detected by the third light detector 2243 of the first optical scanner 2021, the light detected by the third light detector 2243 of the second optical scanner 2022, and the light detected by the third light detector 2243 of the Nth optical scanner 2023 are combined at the optical combiner 506 (forming a second combined light signal 5182). N The light detected by the third optical detector 2243 of the optical combiner 506 is combined at the optical combiner 506 (forming a third combined light signal 5183). Similarly, the index light detected by the index light detector 226 of the first optical scanner 2021, the index light detected by the index light detector 226 of the second optical scanner 2022, and the index light detected by the index light detector 226 of the Nth optical scanner 202 N The index light detected by the index light detector 226 is combined at the optical combiner 506 (forming a combined index light signal 518). I The combined optical signal 518 includes a first combined optical signal 5181, a second combined optical signal 5182, a third combined optical signal 5183 and a combined index optical signal 518 I .

[0068] The light / index light detection device 508 is configured to detect the combined index light signal 518 from the optical combiner 506. I And generate index light detection data 522 (including a pulse signal in this example). In addition, the error signal generator 501 (also called a feedback generator) generates feedback data 524 based on the index light detection data 522. The drive function generator 504 can also generate a plurality of periodic signals (e.g., first periodic signal 5141 to periodic signal 5144) based on the feedback 524 from the feedback generator 501. N Collectively referred to as periodic signals 514 1...N ).

[0069] Figure 5BA block diagram of an example scanning system 500 configured with a scan data processing unit 502 according to some embodiments of the present disclosure is shown. The light / index light detection device 508 can be configured to detect the first combined light signal 5181, the second combined light signal 5182, and the third combined light signal 5183 from the optical combiner 506 and generate scan data (including analog signals in this example). In addition, the scan data processing unit 502 is configured to process the scan data from the light / index light detection device 508 and generate processed scan data (e.g., digital scan data).

[0070] Fig. 6A A block diagram of an example scanning system 600 configured with a drive function generator 604, a first optical scanner 2021, a second optical scanner 2022, an optical combiner 606, a light / index light detection device 608, and an error signal generator 601 is shown in accordance with some embodiments of the present disclosure. 1,2 Each optical scanner in the embodiment includes a light detector unit 212, a light source unit 214, and a movable mirror 210 (e.g., an oscillating mirror) configured to oscillate based on a corresponding periodic signal 614 (e.g., a signal based on a sine function, a signal based on a cosine function) from a drive function generator 604. The drive function generator 604 can be configured to provide a first periodic signal 6141 to the first optical scanner 2021 based on a sine function with a first phase shift (in this example, a 0 phase shift) and to provide a second periodic signal 6142 to the second optical scanner 2022 based on a cosine function equivalent to a sine function with a second phase shift (e.g., a 1 / 4 period phase shift). In addition, the optical scanner 202 1,2 Each optical scanner in the optical combiner 606 communicates (e.g., via optical fiber communication). In this example, each optical scanner 202 is configured to transmit a signal containing the signal from the optical detector 224. 1-3 and the optical information or optical signal 616 of the light / index light detected by the index light detector 226 1,2 Therefore, the optical combiner 606 converts the optical signal 616 into 1,2The optical signals 618 are combined into a combined optical signal 618. For example, the light detected from the first optical detector 2241 of the first optical scanner 2021 and the light detected from the first optical detector 2241 of the second optical scanner 2022 are combined at the optical combiner 606 (forming a first combined optical signal 6181). Similarly, the light detected from the second optical detector 2242 of the first optical scanner 2021 and the light detected from the second optical detector 2242 of the second optical scanner 2022 are combined at the optical combiner 606 (forming a second combined optical signal 6182). Likewise, the light detected from the third optical detector 2243 of the first optical scanner 2021 and the light detected from the third optical detector 2243 of the second optical scanner 2022 are combined at the optical combiner 606 (forming a third combined optical signal 6183). Similarly, the index light detected from the index light detector 226 of the first optical scanner 2021 and the index light detected from the index light detector 226 of the second optical scanner 2022 are combined at the optical combiner 606 (forming a combined index light signal 6181). In this example, the combined light signal 618 includes the first combined light signal 6181, the second combined light signal 6182, the third combined light signal 6183, and the combined index light signal 618 I .

[0071] The light / index light detection device 608 may also be configured to detect the combined index light signal 618 from the optical combiner 606. I And generates index light detection data 622 (including a pulse signal in this example). The error signal generator 601 (also called a feedback generator) generates feedback data 624 based on the index light detection data 622 1,2 (or feedback), and the drive function generator 604 can generate a first periodic signal 6141 based on the first feedback data 6241, and generate a second periodic signal 6142 based on the second feedback 6242 from the feedback generator 601.

[0072] Figure 6B A block diagram of an example scanning system 600 configured with a scan data processing unit 602 is shown. As shown, a light / index light detection device 608 detects a first combined light signal 6181, a second combined light signal 6182, and a third combined light signal 6183 from an optical combiner 606, and generates scan data (including an analog signal in this example). The scan data processing unit 602 is configured to process the scan data from the light / index light detection device 608 and generate processed scan data (e.g., digital scan data).

[0073] Figure 6CA first periodic signal 6141 and a second periodic signal 6142 are shown according to some embodiments of the present disclosure. As discussed, the first movable mirror 2101 oscillates based on the first periodic signal 6141, and the second movable mirror 210 oscillates based on the second periodic signal 6142. As described above, the second periodic signal 6142 is equivalent to the first periodic signal 6141 phase-shifted by 1 / 4 period T). For example, when the movable mirror 210 is rotated by an angle greater than θ0 in the first direction or by an angle less than -θ0 in the second direction, the movable mirror 210 is no longer in a position to reflect or redirect light from the light source 214 onto the light detector unit 212 (e.g., the instantaneous angle θ of the movable mirror 210). Therefore, when the first movable mirror 2101 is at +θ0 (e.g., in this example, Figure 6C , which corresponds to about 0.7 in θ0 (in this example, Figure 6C When the first optical scanner 6021 is actively scanning, the first optical scanner 6021 is actively scanning. Similarly, when the second movable mirror 2102 is at +θ0 (e.g., in this example, Figure 6C is about 0.7) and -θ0 (for example, in this example, Figure 6C When the optical signal 6161 is between 0.01 and 0.07 (about -0.7), the second optical scanner 6022 will generate an image. Therefore, the first optical scanner 2021 generates the first optical signal 6161 in the period "A", the period "C" and the period "E". Similarly, the second optical scanner 2022 generates the second optical signal 6162 in the period "B" and the period "E".

[0074] In this example, the scan data / index detection data corresponding to the period "A", period "C" and period "E" are from the first optical scanner 2021. Likewise, the scan data / index detection data corresponding to the period "B" and period "D" are from the second optical scanner 2022. The instantaneous angle θ of the movable mirror 210 at time t is determined by θ(t)=k×I(t), where I(t) can be based on a periodic function (e.g., sine function, cosine function) that repeats for each period T, and k is a proportional constant that can vary.

[0075] Fig.6DThe index light detection data 622 according to some embodiments of the present disclosure is shown. The pulse signals described herein (e.g., a left pulse signal corresponding to the left index light 218, a middle pulse signal corresponding to the middle index light 219, a right pulse signal corresponding to the right index light 220) are generated by the index light detector 226 and the light / index light detection device 608 in response to detecting the index light from the index light sources 218, 219, 220. In addition, the movable mirror 210 rotates or oscillates based on a periodic function (e.g., a sine function, a cosine function) based on the periodic signal. For example, the movable mirror 210 is initially in a horizontal position. At this time (at 0°), the index light detector 226 detects the middle index light 219 and the light / index light detection device 608 outputs a pulse signal M1. When the movable mirror 210 rotates to the right, the index light detector 226 detects the right index light 220 (at 45° in this example), and the light / index light detection device 608 outputs a pulse signal R1. The movable mirror 210 keeps rotating in the right direction and changes the rotation direction to the left (at 90° in this example). When the movable mirror 210 rotates to the left, the index light detector 226 detects the right index light 220 (at 45° in this example), and the light / index light detection device 608 outputs a pulse signal R2. The movable mirror 210 keeps rotating to the left. When the movable mirror 210 is in a horizontal position (at 0°), the index light detector 226 detects the middle index light 219 and the light / index light detection device 608 outputs a pulse signal M2. When the movable mirror 210 keeps rotating to the left, the index light detector 226 detects the left index light 198 (at -45° in this example), and the light / index light detection device 608 outputs a pulse signal L1. The movable mirror 210 keeps rotating in the left direction and changes the rotation direction to the right (at -90° in this example). When the movable mirror 210 rotates to the right, the index light detector 226 detects the left index light 198 (at -45° in this example), and the light / index light detection device 608 outputs a pulse signal L2. The movable mirror 210 keeps rotating to the right. When the movable mirror 210 is in the horizontal position (0°), the index light detector 226 detects the middle index light 219 and the light / index light detection device 608 outputs a pulse signal M3.

[0076] The error signal generator 601 may have all the information about the periodic function used to generate the first signal 6141. This information may include the length of the period T of the function. However, as will be shown, the error generation is a ratiometric and is therefore independent of the parameters of the drive function.

[0077] Since the exemplary scanning system 600 operates with a ninety-degree phase difference, the interval time TI1 between the pulse signal R1 and the pulse signal R2 is ¼ of the period T.

[0078] Due to environmental influences, the amplitude (also referred to as k) of the first periodic signal 6141 may be changed (based on a sine function). For example, when the amplitude is greater than a normal value (eg, 1), the interval time TI1 between the pulse signal R1 and the pulse signal R2 will increase.

[0079] The error signal generator 601 may generate feedback 6241 (eg, a linear error signal ES) based on the following formula:

[0080]

[0081] Wherein, the period of the sine function used to generate the first periodic signal 6141 is T, and the interval time between the pulse signal R1 and the pulse signal R2 is TI 1. In response to the feedback 6241, the drive function generator 604 is configured to adjust the first periodic signal 6141. For example, when the feedback 6241 indicates a positive value, the drive function generator 604 reduces the amplitude of the first periodic signal 6141 (e.g., proportionally reduces the amplitude of the first periodic signal 6141). Similarly, when the feedback 6241 indicates a negative value, the drive function generator 604 increases the amplitude of the first periodic signal 6141 (e.g., proportionally increases the amplitude of the first periodic signal 6141).

[0082] The instantaneous angle θ of the movable mirror 210 can be determined by the following formula:

[0083] θ(t)=k×I(t) (Formula 1) Wherein, I(t) may be based on a sine function (e.g., sin(wt)). However, due to imperfect alignment with the movable mirror 210, an offset term may be unintentionally added to the sine function. For example, when the first movable mirror 2101 is not aligned with the first light source unit 2141, the instantaneous angle θ of the first movable mirror 2101 operates based on the following formula:

[0084] θ(t)=k×I(t)+b (Equation 3) The bias term b introduced by imperfect alignment can be determined by:

[0085] b=TI 1-TI 2 (Formula 4) wherein the interval time between the pulse signal R1 and the pulse signal R2 is TI 1, and the interval time between the pulse signal L1 and the pulse signal L2 is TI 2. The error signal generator 601 may calculate the offset b using Formula 4. In response to calculating the offset b introduced by the imperfect alignment, the drive function generator 604 may provide a first periodic signal 6141 based on a function with a cancellation (-b):

[0086] θ(t)=k×I(t)+(-b) (Formula 5)

[0087] Therefore, a first periodic signal 6141 is provided to the first movable mirror 2101, which is configured to counteract the offset caused by the imperfect alignment.

[0088] Fig. 6E 622 according to some embodiments of the present disclosure. The movable mirror 210 oscillates based on a periodic signal (e.g., a sine function, a cosine function). For example, the first movable mirror 2101 is initially in a horizontal position. At this time (at 0°), the index light detector 226 of the first optical scanner 2021 detects the intermediate index light 219 and outputs a pulse signal M1, a pulse signal M2, and a pulse signal M3.

[0089] like Fig. 6E As shown, the intermediate index light 219 of the first optical scanner 2021 is detected at an erroneous time t2 (as indicated by the pulse signal M2d) due to an unexpected delay (unexpected phase shift) caused by one or more reasons such as a delay in the operation of the electromechanical device 211. In other words, the first movable mirror 2101 is in a horizontal position (e.g., at t2 instead of t1) Fig.6D The pulse signal M2 in , at the center of the period T of the function used to generate the first periodic signal 6141) is due to the unintended phase shift. Therefore, the instantaneous angle θ of the first movable mirror 2101 operates with an unintended phase shift α:

[0090] θ(t)=k×sin(wt+α) (Formula 6)

[0091] The error signal generator 601 can provide feedback 6241 (e.g., a linear phase error signal) based on the determined delay time D, the time interval between time t1 and time t2. In response to the feedback 6241, the drive function generator 604 can determine the unintended phase shift α, and can provide a first periodic signal 6141 based on the function shown with phase shift cancellation (-α):

[0092] θ(t)=k×sin(wt+(-α)) (Formula 7)

[0093] Similarly, other optical scanners (eg, the second optical scanner 2022 ) may be calibrated. For example, unintended amplitudes, offsets, and phase shifts of the second optical scanner 2022 may be determined based on the index light detection data 622 .

[0094] The methods and systems described herein can be used to correct bias errors in the scanning mirrors of each optical scanner and / or to compensate for the phase response of the scanning mirrors of each optical scanner when scanning an object or during a training cycle. In addition, methods and systems for controlling multiple scanning amplitudes subject to various proportionality constants k (also referred to as amplitudes) are disclosed.

[0095] Figure 7 A flowchart of an example method 700 for controlling a scanning system 600 including a plurality of optical scanners (e.g., a first optical scanner 2021, a second optical scanner 2022, etc.) according to some embodiments of the present disclosure is shown. The method 700 may be performed by a processing logic, which may include hardware (circuitry, dedicated logic, processor, memory, etc.), software (such as software running on a general-purpose computer system or a dedicated machine), or a combination of both, and the processing logic may be included in any computer system or device. Memory hardware The memory communicates with the data processing hardware. The memory hardware is also configured to store instructions that, when executed on the data processing hardware, cause the data processing hardware to perform operations. The operations include receiving index light detection data from the optical scanner. The operations also include determining a bias error of a movable mirror of the optical scanner based on the index light detection data. The operations include determining a phase shift error of a movable mirror of the optical scanner based on the index light detection data. The operations also include determining an amplitude error of a movable mirror of the optical scanner based on the index light detection data. To simplify explanation, the methods described herein are depicted and described as a series of actions. However, actions according to the present disclosure may occur in different orders and / or simultaneously, and may occur simultaneously with other actions not presented and described herein. In addition, not all actions shown may be used to implement methods according to disclosed themes. In addition, those skilled in the art will appreciate and understand that methods may alternatively be represented as a series of interrelated states via state diagrams or events. In addition, methods disclosed in this specification can be stored on products such as non-transient computer-readable media to facilitate transmission and transmission of such methods to computing devices. As those skilled in the art will appreciate, products include computer programs accessible from any computer-readable device or storage medium. Although illustrated as discrete blocks, different blocks may be divided into additional blocks, combined into fewer blocks, or eliminated, depending on the desired implementation.

[0096] The method 700 includes providing a first periodic signal and a second periodic signal to a first optical scanner and a second optical scanner by a function generator at operation 702. For example, operation 702 may use the function generator 604, a first periodic signal 6141, and a second periodic signal 6142. The drive function generator 604 may be configured to generate the first periodic signal 6141 based on a sine function, and the drive function generator 604 generates the second periodic signal 6142 based on a sine function with a 1 / 4 period phase shift. The first movable mirror 2101 oscillates based on the first periodic signal 6141, and the second movable mirror 2102 oscillates based on the second periodic signal 6142.

[0097] Method 700 includes obtaining index light detection data from an optical scanner at operation 704. For example, the operation may use error signal generator 601, index light detection data 622 from light / index light detection device 608. As discussed above, Fig.6D As shown, the index light detection data 622 includes a pulse signal generated by the light / index light detection device 608 in response to detecting the index light from the index light sources 218 , 219 , and 220 .

[0098] The method 700 includes determining and correcting a bias error of the first movable mirror based on the index light detection data and determining and correcting a bias error of the second movable mirror based on the index light detection data at operation 706. During operation 706, as discussed above, determining and correcting / compensating (e.g., by adding an offset bias value) can be performed by the error signal generator 601 (and the drive function generator 604) using the bias error of the first movable mirror 2101 based on the index light detection data 622 and the bias error of the second movable mirror 2102 based on the index light detection data 622.

[0099] The method 700 includes determining and correcting a phase shift error of the first movable mirror based on the index light detection data and determining and correcting a phase shift error of the second movable mirror based on the index light detection data at operation 708. As discussed above, the determination and correction / compensation (e.g., by adding a counteracting phase shift value) of the phase shift error of the first movable mirror 2101 by the error signal generator 601 (and the drive function generator 604) can be based on the index light detection data 622 and the operation 708 of determining and correcting / compensating the phase shift error of the second movable mirror 2102 is based on the index light detection data 622.

[0100] The method 700 includes determining and correcting an amplitude error of the first movable mirror based on the index light detection data and determining and correcting an amplitude error of the second movable mirror based on the index light detection data at operation 710. As discussed above, the operation 710 of determining and correcting / compensating (e.g., by adjusting the amplitude) the amplitude error of the first movable mirror 2101 by the error signal generator 601 (and the drive function generator 604) can be based on the index light detection data 622 and determining and correcting / compensating the amplitude error of the second movable mirror 2102 based on the index light detection data 622.

[0101] Operations 702 to 710 may be performed while the scanning system 600 is scanning an object.

[0102] The disclosed method, apparatus and system allow multiple optical scanners to be controlled with a single set of electronics. In addition, the method, apparatus and system provide for correcting bias errors in the scanning mirrors of each optical scanner, for compensating for the phase response of the scanning mirrors of each optical scanner, and / or for adjusting the proportionality constant k.

[0103] Although preferred embodiments of the present invention have been shown and described herein, it will be apparent to those skilled in the art that these embodiments are provided by way of example only. Without departing from the present invention, those skilled in the art will appreciate that many variations, changes and replacements are possible. It should be understood that the different alternatives of the embodiments of the present invention described herein may be used to practice the present invention. It is intended that the claims define the scope of the present invention, and thus cover methods and structures within the scope of these claims and their equivalents.

Claims

1. A scanning system, comprising: a drive function generator configured to generate a plurality of periodic signals, the plurality of periodic signals comprising a first periodic signal and a second periodic signal; a plurality of optical scanners, including a first optical scanner and a second optical scanner; a first mirror of the first optical scanner; and a second mirror of the second optical scanner; wherein the first mirror oscillates based on the first periodic signal, wherein the second mirror oscillates based on the second periodic signal, and Therein, the first periodic signal has a first phase shift and the second periodic signal has a second phase shift different from the first phase shift.

2. The scanning system according to claim 1, wherein: The first phase shift is 0, and The second phase shift is 1 / 4 period of the second periodic signal.

3. The scanning system according to claim 1, wherein: The driving function generator generates the first periodic signal with a first phase shift based on a first sinusoidal function, The drive function generator generates the second periodic signal with a second phase shift based on the first sinusoidal function.

4. The scanning system according to claim 3, wherein: The first phase shift is 0, and The second phase shift is 1 / 4 period of the first sinusoidal function.

5. The scanning system according to claim 1, wherein: The first optical scanner comprises: A light source device, comprising a light source array, The first index light source, a second index light source, and The third index light source.

6. The scanning system of claim 5, wherein: The first index light source is aligned with a first column of the light source array, and The second index light source is aligned with the last column of the light source array.

7. The scanning system according to claim 5, wherein: The third index light source is aligned with a center line between a first column of the light source array and a last column of the light source array.

8. The scanning system according to claim 5, wherein: The third index light source is aligned with a middle column of the light source array.

9. The scanning system according to claim 5, wherein: The first optical scanner further comprises: A light detector unit includes a light detector and an index light detector, the light detector corresponding to a row of the light source array, the index light detector being arranged to detect index light from the first index light source, the second index light source, and the third index light source.

10. The scanning system according to claim 1, further comprising: A scan data processor is configured to receive scan data from the plurality of optical scanners.

11. A method for correcting a periodic signal, the method comprising: At one or more processors, receiving index light detection data from an optical scanner; determining, by the one or more processors, a bias error of a movable mirror of the optical scanner based on the index light detection data; determining, by the one or more processors, a phase shift error of a movable mirror of the optical scanner based on the index light detection data; An amplitude error of a movable mirror of the optical scanner is determined, by the one or more processors, based on the index light detection data.

12. The method according to claim 11, wherein: Determining the amplitude error of the movable mirror includes determining a time interval between two consecutive pulses generated by right index light in the index light detection data.

13. The method according to claim 12, further comprising: In response to determining that the amplitude error exists, an amplitude of a function used to generate a signal to drive the movable mirror is adjusted by the one or more processors.

14. The method according to claim 11, wherein: Determining the phase shift error of the movable mirror includes determining a time interval between a first time when an intermediate index pulse is generated by detecting intermediate index light and a second time when the intermediate index pulse is expected to be generated.

15. The method according to claim 14, further comprising: In response to determining that the phase shift error exists, a cancelling phase shift is added, by the one or more processors, to a function used to generate a signal that drives the movable mirror.

16. The method of claim 11, wherein: Determining the bias error of the movable mirror includes determining a first time interval between two consecutive pulses generated by right index light in the index light detection data, and determining a second time interval between two consecutive pulses generated by left index light in the index light detection data.

17. The method according to claim 16, further comprising: In response to determining that the bias error exists, a counteracting bias is added, by the one or more processors, to a function used to generate a signal to drive the movable mirror.

18. A scanning system comprising: Data processing hardware; as well as Memory hardware in communication with the data processing hardware, the memory hardware being configurable to store instructions that, when executed on the data processing hardware, cause the data processing hardware to perform operations, the operations comprising: receiving index light detection data from an optical scanner; determining a bias error of a movable mirror of the optical scanner based on the index light detection data; determining a phase shift error of a movable mirror of the optical scanner based on the index light detection data; An amplitude error of a movable mirror of the optical scanner is determined based on the index light detection data.

19. The scanning system of claim 18, wherein: Determining the amplitude error of the movable mirror includes determining a time interval between two consecutive pulses generated by right index light in the index light detection data.

20. The scanning system of claim 19, the operations further comprising: In response to determining that the amplitude error exists, an amplitude of a function used to generate a signal to drive the movable mirror is adjusted.

21. The scanning system of claim 18, wherein: Determining the phase shift error of the movable mirror includes determining a time interval between a first time when an intermediate index pulse is generated by detecting intermediate index light and a second time when the intermediate index pulse is expected to be generated.

22. The scanning system of claim 21, the operations further comprising: In response to determining that the phase shift error exists, a counteracting phase shift is added to a function used to generate a signal that drives the movable mirror.

23. The scanning system of claim 18, wherein: Determining the bias error of the movable mirror includes determining a first time interval between two consecutive pulses generated by right index light in the index light detection data, and determining a second time interval between two consecutive pulses generated by left index light in the index light detection data.

24. The scanning system of claim 21, the operations further comprising: In response to determining that the bias error exists, a counteracting bias is added to a function used to generate a signal to drive the movable mirror.

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