JP6634967B2 - Optical scanning device - Google Patents

Description

  The present invention relates to an optical scanning device that scans a surface to be scanned with a laser beam.

  For HUD (Head-Up Display) and LIDAR (Laser Imaging Detection and Ranging), a MEMS (Micro Electro Mechanical System) scanner is used as an optical device. The MEMS scanner deflects the laser light by swinging a mirror that reflects the laser light at a high speed, that is, scans the surface to be scanned with the laser light. As a device for detecting a scanning angle of a mirror, for example, devices described in Patent Documents 1 and 2 are known.

  In the apparatus disclosed in Patent Document 1, a reflective material is provided on the inner surface of a cover glass that covers a mirror, a light receiving element is provided adjacent to the mirror, and laser light scanned by the mirror is reflected by the reflective material. Is detected by the light receiving element to estimate the scanning angle of the mirror.

  Further, in the device disclosed in Patent Document 2, the reflection type diffraction grating is provided on the reflection surface of the mirror, and the light receiving element array is disposed on the inner surface of the glass cover. Is detected by the light receiving element array, and the scanning angle of the mirror is estimated.

JP 2015-148654 A JP 2011-118178 A

  However, in the case of the device disclosed in Patent Document 1, only the maximum scanning angle of the mirror can be detected. In addition, since the light receiving element is arranged adjacent to the mirror, there is a disadvantage that the configuration of the entire apparatus becomes large.

  Further, in the device of Patent Document 2, it is necessary to mount the light receiving element on the inner surface of the cover glass, so that a special mounting method such as a WLP (Wafer Level Package) has to be adopted, which complicates the manufacturing process. . Further, in the device of Patent Document 2, since the reflection type diffraction grating is used, the zero-order light is used for the scanning light and the primary light is used for estimating the scanning angle. Depending on the angle, the reflected light is reflected in an oblique direction. Therefore, it is necessary to dispose the light receiving element along the oblique direction. This increases the overall configuration of the device and the position at the time of forming the light receiving element and the reflective diffraction grating. There is a problem that the alignment becomes complicated.

  An object of the present invention is to be able to detect a scanning angle of a mirror other than the maximum angle, to prevent the manufacturing process from being complicated, and to obtain effects such as downsizing the configuration of the entire apparatus. An optical scanning device is provided.

The invention according to claim 1 is a MEMS scanner (4) provided with a laser light source (24) for emitting laser light, a mirror (7) for reflecting the laser light and scanning the surface to be scanned, and the mirror ( a transmission type diffraction grating (8) provided on the reflecting surface 7), the laser beam is the transmissive diffraction grating (8) generated by Rukoto to transmit zero-order transmitted diffracted light and transmitting other than zero-order a light receiving element for receiving the diffracted light (6), before Symbol receiving the transmitted diffracted light of the non-zero-order relative to the receiving position of the 0-order transmission diffracted light output from the light receiving element (6) An angle estimating unit (28) for estimating the scanning angle of the laser beam based on a position .

Longitudinal sectional view of an optical scanning device showing a first embodiment. Exploded perspective view of MEMS scanner, wiring board, and light receiving element Top view of MEMS scanner Block diagram of optical scanning device FIG. 4 is a view for explaining scanning angle estimation control Diagram for explaining the correspondence between sensor addresses and scanning angles Diagram showing an example of an angle correspondence data table Flowchart of scanning angle estimation control Diagram illustrating an image sensor FIG. 9 shows a second embodiment, in which (a) is a top view of a mirror, and (b) is a diagram illustrating an intensity distribution of a laser beam. Flowchart of laser light output intensity detection control showing a third embodiment FIG. 9 shows a fourth embodiment, and is a longitudinal sectional view of a MEMS scanner, a wiring board, and a light receiving element. FIG. 14 shows the fifth embodiment, and is a longitudinal sectional view of a MEMS scanner, a wiring board, and a light receiving element. FIG. 13 shows the sixth embodiment, and is a longitudinal sectional view of a MEMS scanner, a wiring board, and a light receiving element. FIG. 14 shows the seventh embodiment, and is a longitudinal sectional view of a MEMS scanner, a wiring board, and a light receiving element.

(1st Embodiment)
Hereinafter, the first embodiment will be described with reference to FIGS. 1 to 9. As shown in FIG. 1, an apparatus main body 1 of the optical scanning device according to the present embodiment includes a rectangular container-shaped package 2 and a transparent cover glass 3 that closes an opening on the upper surface of the package 2. Inside the package 2, the MEMS scanner 4, the wiring board 5, and the light receiving element 6 are stacked and accommodated in this order from top to bottom.

  As shown in FIG. 2, the MEMS scanner 4 is formed of a rectangular thin semiconductor chip (for example, a silicon chip). The MEMS scanner 4 includes a mirror 7 (for example, a MEMS mirror) and is mounted on the upper surface of the wiring board 5. As shown in FIG. 1, the mirror 7 has a first axis D1 and a second axis D2 orthogonal to each other with respect to the package 2 so that the reflection surface is located on the optical path of the laser beam A transmitted through the cover glass 3. It is supported so as to be swingable independently around it (see FIG. 3). The MEMS scanner 4 two-dimensionally deflects the laser light A incident on the mirror 7 by independently swinging the mirror 7 around the first axis D1 and the second axis D2. That is, the MEMS scanner 4 forms a scanning optical system that guides the laser light A from the laser light source 24 (see FIG. 4) to the surface to be scanned F (see FIG. 4).

  A transmission type diffraction grating 8 is formed on a portion of the mirror 7 that reflects the laser beam A, that is, on a reflection surface. As shown in FIG. 1, the transmission diffraction grating 8 transmits a part of the laser beam A applied to the mirror 7 to the back side of the mirror 7 and generates transmission diffraction light B0, B ± 1,. . The transmitted diffracted light B0 is a 0th-order transmitted diffracted light (that is, n = 0 transmitted diffracted light), and the transmitted diffracted light B1 is a first-order transmitted diffracted light (that is, n = 1 transmitted diffracted light). The transmitted diffracted lights B2,... Are transmitted diffracted lights of the second and subsequent orders (that is, transmitted diffracted lights of n ≧ 2). The transmitted diffracted light B-1 is a −1st-order transmitted diffracted light (that is, n = −1 transmitted diffracted light), and the transmitted diffracted lights B-2,. , N ≦ −2).

  The MEMS scanner 4 is housed and sealed in a sealed internal space of the package 2 (that is, the main body device 1), and is protected from dust and moisture. The internal space of the package 2 is filled with an inert gas such as nitrogen, helium, argon, or neon, or is evacuated. The MEMS scanner 4 deflects (ie, scans) the laser light by mechanically swinging the small MEMS mirror 7 at high speed.

  The wiring board 5 has a function as a spacer for forming a space where the mirror 7 of the MEMS scanner 4 swings. The wiring board 5 has a rectangular opening 5a for forming a space in which the mirror 7 swings. The MEMS scanner 4 is mounted on the upper surface of the wiring substrate 5 by, for example, soldering, and the light receiving element 6 is mounted on the lower surface of the wiring substrate 5 by, for example, soldering. Various wiring patterns and control circuits (for example, at least a part of the control circuit 23 shown in FIG. 4) connected to the MEMS scanner 4 and the light receiving element 6 are formed on the upper or lower surface of the wiring board 5. The wiring pattern of the wiring board 5 and the wiring pattern (for example, land) of the MEMS scanner 4 are connected by, for example, through electrodes, wire bonding, bumps, and the like. The wiring pattern of the wiring board 5 and the wiring pattern (for example, land) of the light receiving element 6 are connected by, for example, through electrodes, wire bonding, bumps, and the like. Note that the wiring board 5 is composed of, for example, a silicon substrate, a ceramic substrate, a resin substrate, or the like.

  As shown in FIG. 1, a plurality of lead terminals 9 connected to the above-described various wiring patterns are provided on the periphery of the wiring board 5, and these lead terminals 9 seal the side wall of the package 2. And is configured to protrude to the outside. The wiring board 5 is placed and fixed on a step 2 a provided around the inner bottom of the package 2 in the package 2.

  The light receiving element 6 is formed of a rectangular thin plate-shaped semiconductor chip (for example, a silicon chip). A light receiving sensor array 10 is provided below the mirror 7 of the MEMS scanner 4 on the upper surface of the light receiving element 6. The light receiving sensor array 10 is configured by arranging light receiving sensors such as photodiodes and phototransistors in, for example, a one-dimensional array or a two-dimensional array, and is configured by, for example, a line sensor or an image sensor. I have. In a portion of the light receiving element 6 where the light receiving sensor array 10 is not provided, a sensor circuit (not shown) (for example, a light receiving circuit for processing an output signal from the light receiving sensor array 10) and a control circuit (for example, FIG. It is preferable to provide at least a part of the control circuit 23 shown in FIG.

  Next, the MEMS scanner 4 will be described with reference to FIG. As illustrated in FIG. 3, the MEMS scanner 4 includes a mirror 7 having a reflective surface on the + side of the Y axis and a mirror 7 that drives the mirror 7 around a first axis D1 (for example, the Z axis) orthogonal to the X axis. 1 includes a first driving unit 11 and a second driving unit 12 that drives the mirror 7 and the first driving unit 11 around a second axis D2 parallel to the X axis.

  In the MEMS scanner 4, for example, each component is integrally formed by a MEMS process. The MEMS scanner 4 is created by making a cut in one silicon substrate to form a plurality of movable parts (elastic deformation parts), and providing a piezoelectric member in each movable part. On the reflection surface of the mirror 7, for example, aluminum, gold, silver or the like is formed. Further, on the reflection surface of the mirror 7, a transmission type diffraction grating 8 (see FIG. 2) is formed by forming a periodic slit in the metal thin film, for example. The transmission diffraction grating 8 has a function of transmitting a part of the laser light A incident on the mirror 7 and generating transmitted diffraction light B0, B ± 1,.

  As an example, the first driving unit 11 includes torsion bars 13a and 13b provided at both ends of the mirror 7 in the first axial direction, and an intermediate portion is connected to the other ends of the torsion bars 13a and 13b and extends in the second axial direction. It has beams 14a, 14b, a first rectangular frame 15 having inner edges continuous with both ends of the beams 14a, 14b, and first piezoelectric members 16, 17 provided on the beams 14a, 14b.

  In the first driving unit 11, the mirror 7 is applied by applying (for example, simultaneously) opposite-phase sine-wave voltages to two piezoelectric members 16 and 17 provided separately on the two beams 13a and 14b, respectively. , Can be efficiently oscillated around the first axis D1 at the cycle of the sine wave voltage. For example, when the frequency of the sine wave voltage is set to about 20 kHz (resonance frequency of each torsion bar), the mirror 7 can be oscillated at about 20 kHz using mechanical resonance due to the torsion of each torsion bar. The maximum deflection angle of the mirror 7 from the center of vibration is about ± 30 degrees.

  The second drive unit 12 includes, for example, a meandering portion 19a including a plurality of beams 18a that are continuous at one end at a lower left corner of the first rectangular frame portion 15 and meander, and a first rectangular frame portion 15. A meandering portion 19b including a plurality of beams 18b, one end of which is continuous with the upper right corner of the meandering portion, and eight second piezoelectric members 20, 21 provided on the eight beams 18a of the meandering portion 19a. And eight second piezoelectric members 20, 21 provided on the eight beams 18b of the meandering portion 19b, and a second rectangular frame portion 22 having an inner edge continuous with the other ends of the two meandering portions 19a, 19b.

  In the second driving section 12, the odd-numbered four second piezoelectric members 20 and the even-numbered four second piezoelectric members 21 of the eight second piezoelectric members provided in each meandering section are sawed. By applying the wave voltage and the reverse sawtooth voltage in parallel (for example, simultaneously), the two beams adjacent to the meandering portion are bent in opposite directions around the second axis D2, and the amount of bending of each beam is accumulated. Thus, the mirror 7 can be efficiently vibrated around the second axis D2 at the cycle of the sawtooth voltage (for example, at a low voltage and at a large deflection angle). Here, the “sawtooth voltage” means a voltage that gradually increases as time elapses, and rapidly decreases when reaching a peak. The “reverse sawtooth voltage” means a voltage that increases rapidly with time and gradually decreases when reaching a peak.

  Here, the case where the piezoelectric member is provided only on one surface of the silicon substrate has been described as an example. However, in order to improve the degree of freedom in wiring layout and creation of the piezoelectric member, the piezoelectric member is provided only on the other surface of the silicon substrate. It may be provided on both one surface and the other surface of the silicon substrate.

  Here, when light is incident on the mirror 7 that vibrates around the first axis D1, the reflected light is scanned (deflection scan) around the first axis D1. When light is incident on the mirror 7 that oscillates around the second axis D2, the reflected light is scanned (deflection scan) around the second axis D2. Therefore, in order to increase the definition and uniformity of the image formed on the surface to be scanned F, light incident on the mirror 7 is linearly scanned around the first axis D1, and the scanning line is moved to the first axis D1. Scanning around the two axes D2, that is, raster scanning can be performed.

  As shown in FIG. 4, the optical scanning device of the present embodiment includes a control circuit 23, a laser light source 24, a MEMS scanner 4, and a light receiving element 6. The control circuit 23 has a function of controlling the entire optical scanning device, and includes a laser control unit 25, a synchronization control unit 26, a scanner control unit 27, and an angle estimation unit 28.

  The laser control unit 25 receives the synchronization control signal from the synchronization control unit 26, and controls the drive of the laser light source 24 based on the received synchronization control signal. As a result, for example, pulsed laser light A is emitted from the laser light source 24 and is emitted to the mirror 7 of the MEMS scanner 4. The synchronization control unit 26 receives a drive control signal of the MEMS scanner 4 from the scanner control unit 27, and synchronizes the emission timing of the laser light A with the swing timing of the mirror 7 based on the received drive control signal. , And transmits the generated synchronization control signal to the laser control unit 25 and the scanner control unit 27.

  The scanner control unit 27 receives the synchronization control signal from the synchronization control unit 26, and controls the driving of the first drive unit 11 and the second drive unit 12 of the MEMS scanner 4 based on the received synchronization control signal. As a result, the mirror 7 of the MEMS scanner 4 is swung, and the laser light A reflected by the swiveled reflecting surface of the mirror 7 is scanned on the surface to be scanned F.

  Then, a part of the laser beam A applied to the reflection surface of the mirror 7 passes through the transmission type diffraction grating 8 provided on the reflection surface of the mirror 7, so that the transmission diffraction light B0, B ± 1,. appear. The light receiving sensor array 10 of the light receiving element 6 receives the transmitted diffraction light B0, B ± 1,... And transmits a light receiving signal (for example, data of a detection value of a sensor address) to the angle estimating unit 28. The angle estimating unit 28 receives a light receiving signal from the light receiving element 6 and estimates a scan angle of the mirror 7 of the MEMS scanner 4, that is, a scan angle based on the input light receiving signal. Then, the angle estimating unit 28 transmits information on the estimated scanning angle to the scanner control unit 27. The scanner control unit 27 is configured to perform feedback control of the MEMS scanner 4 based on information on the estimated scanning angle from the angle estimation unit 28.

  Next, the scanning angle estimation function of the angle estimation unit 28 will be described with reference to FIGS. In the following description, the processing for estimating the scanning angle of the mirror 7 when the mirror 7 is swung about the first axis D1 is described. However, when the mirror 7 is swung about the second axis D2. The scanning angle of the mirror 7 can be similarly estimated.

As shown in FIG. 5, when the scanning angle of the mirror 7 is θm, the incident angle of the laser beam A is θin, and the angle of the nth-order transmitted diffracted light Bn is θout-n, the following equation is established.
θout−n = sin ⁻¹ (nλ / d−sin (90−θin−θm)) − θm
Note that d is the slit width of the transmission diffraction grating 8, λ is the wavelength of the laser light A, and n is the order of the transmitted diffraction light. The straight line V is a straight line orthogonal to the reflection surface of the mirror 7.

n = 0, that is, the angle θout-0 of the 0th-order transmitted diffracted light B0 has a constant value regardless of the magnitude of the scanning angle θm.
The angle θout-n of the nth-order transmitted diffracted light Bn where n ≠ 0 increases as the scanning angle θm increases. Further, the interval between the n-th order transmitted diffracted lights Bn increases as the slit width d of the transmission type diffraction grating 8 decreases. Therefore, for example, if the angle θout-1 or θout-(-1) of the transmitted diffracted light of n = 1 or n = -1 is detected, the scanning angle is determined based on the detected angle θout-1 or θout-(-1). θm can be estimated.

  Specifically, when the light receiving sensor array 10 of the light receiving element 6 detects the n-th order diffracted light Bn of n = 1 or n = −1, the detected position is used as the detection data of the sensor address. Then, for example, when the optical scanning device is shipped from the factory, the MEMS scanner 4 is actually operated to measure the scanning angle of the mirror 7, and the sensor address of the light receiving element 6 at the time of the measurement is detected. An angle correspondence data table 29 as shown in FIG. 7 is created in association with the detected data of the detected sensor address, and stored in a memory (for example, a non-volatile memory) in the control circuit 23.

  For example, as shown in FIG. 6A, when the measurement result of the scanning angle of the mirror 7 is 30 degrees, the detection data of the sensor address is (0), and as shown in FIG. If the measurement result of the scan angle is -30 degrees and the detection data of the sensor address is (60), the angle correspondence data table 29 shown in FIG. 7 can be created.

  Here, an example of the scanning angle estimation control by the light receiving element 6 and the angle estimation unit 28 will be described with reference to the flowchart of FIG. First, in step S10 of FIG. 8, for example, the primary transmitted diffracted light B1 is received by the light receiving sensor array 10 of the light receiving element 6, the sensor address is detected, and the detection data is sent to the angle estimating unit 28 of the scanner control unit 27. Send. Subsequently, the process proceeds to step S20, in which the angle estimating unit 28 receives (ie, acquires) the light receiving position of the diffracted light, that is, the detection data of the sensor address from the light receiving element 6. Next, proceeding to step S30, the angle estimating unit 28 estimates the scanning angle based on the received detection data of the sensor address and the angle correspondence data table 29 shown in FIG. Then, the angle estimating unit 28 transmits the estimated scanning angle to the scanner control unit 27.

  The angle correspondence data table 29 shown in FIG. 7 is a data table for estimating the scanning angle of the mirror 7 around the first axis D1. As the light receiving sensor array 10 of the light receiving element 6, a one-dimensional sensor such as a line sensor is used. Using a sensor.

  On the other hand, when a two-dimensional sensor such as an image sensor 30 as shown in FIG. 9 is used as the light receiving sensor array 10 of the light receiving element 6, the scanning angles of the mirror 7 around the first axis D1 and the second axis D2 can be changed. Can be estimated. In this case, the horizontal detection position of the two-dimensional sensor 30 in FIG. 9 corresponds to the scanning angle around the first axis D1, and the vertical detection position of the two-dimensional sensor 30 in FIG. This corresponds to a scan angle around D2. In the case of this configuration, a two-dimensional angle correspondence data table in which the two-dimensional detection positions of the two-dimensional sensor 30 are associated with the respective scanning angles around the first axis D1 and the second axis D2 of the mirror 7 is created. Then, it is preferable that the created two-dimensional angle correspondence data table is stored in the memory of the control circuit 23.

  The optical scanning device according to the present embodiment having such a configuration includes a laser light source 24 that emits a laser beam, a MEMS scanner 4 provided with a mirror 7 that reflects a laser beam A and scans a scanned surface F, 7, a transmission diffraction grating 8 provided on the reflection surface, a light-receiving element 6 for receiving transmission diffraction light other than the 0th order generated by the laser beam A passing through the transmission diffraction grating 8, and an output from the light-receiving element 6. And an angle estimating unit 28 for estimating the scanning angle of the laser beam A based on the received light signal. According to this configuration, the mirror 7 other than the maximum angle, that is, the scanning angle of the laser beam A can be detected, and the manufacturing process can be prevented from being complicated. Further, in the above configuration, since the diffracted light is received by the light receiving sensor array 10 near the mirror 7, the spread of the diffracted light can be suppressed, so that the light receiving sensor array 10 can be reduced in size and the optical scanning can be performed. An increase in the area of the device in the lateral direction can be suppressed.

  Further, in the above embodiment, since the MEMS scanner 4, the wiring substrate 5, and the light receiving element 6 are vertically stacked, an increase in the volume of the optical scanning device in the vertical direction can be suppressed. Further, in the above embodiment, since the 0th-order transmitted diffracted light B0 always irradiates the same position, if the light receiving sensor array 10 of the light receiving element 6 is arranged in parallel with the scanning direction based on the position. Good things make the alignment work easier.

  In the above embodiment, since the wiring board 5 is provided as a spacer between the MEMS scanner 4 and the light receiving element 6, a space in which the mirror 7 of the MEMS scanner 4 swings can be reliably formed. Since the MEMS scanner 4 and the light receiving element 6 are mounted on the wiring board 5 by, for example, soldering, the workability of mounting can be improved and the electrical connection can be simplified.

  In the above embodiment, the MEMS scanner 4 is formed of a silicon substrate, the light receiving element 6 is formed of a silicon substrate, and the wiring substrate 5 is formed of a silicon substrate. Can be set to In the above-described embodiment, the mirror 7 is provided so as to swing around the first axis D1, and the mirror 7 is provided so as to swing around a second axis D2 orthogonal to the first axis D1. The estimating unit 28 calculates a scanning angle of the laser light A around the first axis D1 and a scanning angle of the laser light A around the second axis D2 based on the light receiving signal output from the image sensor 30 of the light receiving element 6. Was estimated. According to this configuration, the scanning angle of the laser beam A around the first axis D1 and the scanning angle of the laser beam A around the second axis D2 can be easily and accurately estimated.

  In the above embodiment, at least a part of the control circuit 23 for controlling the optical scanning device is provided on the semiconductor chip (semiconductor substrate) provided with the light receiving element 6, so that the degree of integration of the semiconductor chip circuit is increased. Therefore, noise resistance and manufacturing workability can be improved.

(2nd Embodiment)
FIG. 10 shows a second embodiment. The same components as those of the first embodiment are denoted by the same reference numerals. In the first embodiment, when the transmission diffraction grating 8 is provided on the reflection surface of the mirror 7, the arrangement position is not particularly limited, and may be any location where the laser beam A is irradiated. It has become.

  On the other hand, in the second embodiment, as shown in FIG. 10A, on the reflection surface of the mirror 7, the irradiation portion 31 irradiated with the laser light A, for example, the irradiation portion 31 indicated by a broken-line circle is formed. A transmission diffraction grating 8 was provided on the inner peripheral portion. Since the intensity distribution of the laser light is close to a normal distribution as shown in FIG. 10B, the intensity of the laser light is high near the center of the irradiated portion 31 and the peripheral edge of the irradiated portion 31 is Low strength. For this reason, if the transmission diffraction grating 8 is arranged near the center of the irradiation part 31 on the reflection surface of the mirror 7, the intensity of the laser light reflected by the mirror 7 becomes small, that is, the intensity of the laser light used for scanning is reduced. Since the intensity is reduced, a problem that scanning efficiency is deteriorated occurs.

  In order to solve such a problem, in the second embodiment, the transmission type diffraction grating 8 is provided at the peripheral edge of the laser light irradiation portion 31 on the reflection surface of the mirror 7, so that the laser used for scanning is not used. The transmission diffraction grating 8 can generate the transmitted diffraction light B0, B ± 1,... Without reducing the light intensity as much as possible, that is, without deteriorating the scanning efficiency as much as possible.

  The configuration of the second embodiment other than that described above is the same as the configuration of the first embodiment. Therefore, also in the second embodiment, substantially the same operation and effect as in the first embodiment can be obtained. In particular, according to the second embodiment, the transmission type diffraction grating 8 is provided on the peripheral portion of the laser light irradiation portion 31 on the reflection surface of the mirror 7, so that the scanning efficiency can be prevented from being deteriorated as much as possible. it can.

(Third embodiment)
FIG. 11 shows a third embodiment. The same components as those in the first embodiment are denoted by the same reference numerals. The zero-order transmitted diffraction light B0 is applied to a fixed position even when the scanning angle changes. The intensity of the laser beam and the intensity of the zero-order transmitted diffracted light B0 are in a proportional relationship. Therefore, in the third embodiment, when the 0th-order transmitted diffraction light B0 is received by the light receiving sensor array 10 of the light receiving element 6, the intensity of the 0th-order transmitted diffraction light B0 is detected, and the detected 0th-order transmitted diffraction light B0 is detected. The configuration is such that the intensity of the laser beam is detected based on the intensity of the transmitted diffraction light B0.

  Specifically, the output level of a light reception output signal output when the 0th-order transmitted diffracted light B0 is detected by the light reception sensor array 10 of the light reception element 6, for example, an A / D conversion output obtained by A / D conversion of the light reception output signal. The signal is transmitted to the control circuit 23. Then, the control circuit 23 generates the laser light based on the received A / D conversion output signal of the 0th-order transmitted diffracted light B0 and the intensity correspondence data table (not shown) stored in the memory of the control circuit 23 in advance. The intensity is determined (ie, detected). The control circuit 23 has a function as an intensity estimating unit.

  When the optical scanning device is shipped from the factory, the optical scanning device is actually operated to measure the output intensity while changing the output intensity of the laser beam A, and the A / of the zero-order transmitted diffraction light B0 at the time of the measurement is measured. The D-converted output signal is acquired, and the intensity-corresponding data table is created by associating the measured intensity of the laser light A with the output voltage level data of the acquired A / D-converted output signal of the zero-order transmitted diffracted light B0. However, it is preferable that the information is stored in a memory (for example, a non-volatile memory) in the control circuit 23.

  Here, an example of intensity detection control by the light receiving element 6 and the control circuit 23 will be described with reference to the flowchart of FIG. First, in step S110 of FIG. 11, transmitted light is received by the light receiving sensor array 10 of the light receiving element 6. Subsequently, the process proceeds to step S120, where the light receiving element 6 receives, for example, the 0th-order transmitted diffracted light by the light receiving sensor array 10, and outputs the output level of the received light output signal (that is, the received light output level), for example, A / A. The D / A converted output signal is transmitted to the control circuit 23. Then, the process proceeds to step S130, where the control circuit 23 determines whether or not the laser light has been converted based on the received A / D conversion output signal of the 0th-order transmitted diffracted light B0 and the intensity correspondence data table stored in the memory of the control circuit 23. The output intensity is determined (ie, detected). The detected output intensity of the laser light can be used in the control circuit 23 for feedback control such as drive control of the laser light source 24.

  The configuration of the third embodiment other than that described above is the same as the configuration of the first embodiment. Therefore, also in the third embodiment, substantially the same operation and effect as in the first embodiment can be obtained. In particular, according to the third embodiment, the output intensity of the laser beam can be detected based on the received light output signal of the zero-order transmitted diffracted light B0.

(Fourth embodiment)
FIG. 12 shows a fourth embodiment. The same components as those in the first embodiment are denoted by the same reference numerals. In the fourth embodiment, the semiconductor chip 32 of the light receiving element 6 provided with the light receiving sensor array 10 is provided on the right side in FIG. The semiconductor chip 34 provided with the control circuit 33 is arranged on the left side of the block 12.

  The configuration of the fourth embodiment other than the above is the same as the configuration of the first embodiment. Therefore, also in the fourth embodiment, substantially the same operation and effect as in the first embodiment can be obtained.

(Fifth embodiment)
FIG. 13 shows a fifth embodiment. The same components as those in the first embodiment or the fourth embodiment are denoted by the same reference numerals. In the fifth embodiment, in the configuration for receiving the transmitted diffracted light B (−1) of n = −1, as shown in FIG. 13, the left half of the semiconductor chip 35 of the light receiving element 6 provided with the light receiving sensor array 10 , A control circuit 36 is provided.

  The configuration of the fifth embodiment other than that described above is the same as the configuration of the first embodiment or the fourth embodiment. Therefore, also in the fifth embodiment, it is possible to obtain substantially the same operation and effect as in the first embodiment or the fourth embodiment.

(Sixth embodiment)
FIG. 14 shows a sixth embodiment. The same components as those in the first embodiment or the fourth embodiment are denoted by the same reference numerals. In the sixth embodiment, the semiconductor chip 37 of the light-receiving element 6 provided with the light-receiving sensor array 10 is provided on the left side in FIG. On the right side, a semiconductor chip 39 provided with a control circuit 38 is provided.

  The configuration of the sixth embodiment other than that described above is the same as the configuration of the first embodiment or the fourth embodiment. Therefore, also in the sixth embodiment, it is possible to obtain substantially the same operation and effect as in the first embodiment or the fourth embodiment.

(Seventh embodiment)
FIG. 15 shows a seventh embodiment. The same components as those in the sixth embodiment are denoted by the same reference numerals. In the seventh embodiment, as shown in FIG. 15, the semiconductor chip 37 of the light receiving element 6 provided with the light receiving sensor array 10 is divided into two semiconductor chips 40 and 41 in a configuration for receiving the transmitted diffracted light B1 of n = 1. The light receiving sensor array 10 was provided on one (right) semiconductor chip 40, and the control circuit 42 was provided on the other (left) semiconductor chip 41.

  The configuration of the seventh embodiment other than that described above is the same as the configuration of the sixth embodiment. Therefore, also in the seventh embodiment, substantially the same operation and effect as in the sixth embodiment can be obtained.

  Further, in each of the above embodiments, the MEMS scanner 4 and the light receiving element 6 are configured to be mounted on the wiring board 5, but the present invention is not limited to this. May be implemented. In such a configuration, it is preferable to provide a spacer between the MEMS scanner 4 and the light receiving element 6 in order to form a space in which the mirror 7 swings. In the case of the above configuration, it is preferable that the wiring pattern (for example, land) of the MEMS scanner 4 and the wiring pattern (for example, land) of the light receiving element 6 are connected by, for example, through electrodes, wire bonding, bumps, or the like. In addition, in the case of the above configuration, if the through electrode or the bump is configured to have a function as a spacer, it is not necessary to separately provide a spacer.

  In the drawings, reference numeral 1 denotes an apparatus main body, 2 denotes a package, 3 denotes a cover glass, 4 denotes a MEMS scanner, 5 denotes a wiring board, 6 denotes a light receiving element, 7 denotes a mirror, 8 denotes a transmission type diffraction grating, 10 denotes a light receiving sensor array, and 23 Is a control circuit, 24 is a laser light source, 27 is a scanner control unit, 28 is an angle estimating unit, 29 is an angle correspondence data table, and 30 is an image sensor.

Claims (6)

A laser light source (24) for emitting laser light;
A MEMS scanner (4) provided with a mirror (7) for reflecting the laser light and scanning the surface to be scanned;
A transmission diffraction grating (8) provided on a reflection surface of the mirror (7);
A light receiving element (6) in which the laser light is received and said transmission diffraction grating (8) generated by Rukoto be transmitted zero-order transmitted diffracted light and 0-order non-transmitted diffracted light,
An angle for estimating a scanning angle of the laser beam based on a light receiving position of the transmitted diffraction light other than the zeroth order with reference to a light receiving position of the zeroth transmitted diffraction light output from the light receiving element (6). An optical scanning device comprising an estimation unit (28).   The optical scanning device according to claim 1, wherein a wiring board (5) is provided as a spacer between the MEMS scanner (4) and the light receiving element (6). The MEMS scanner (4) is constituted by a silicon substrate,
The light receiving element (6) is formed of a silicon substrate,
The optical scanning device according to claim 2, wherein the wiring substrate (5) is formed of a silicon substrate. The mirror (7) is provided so as to swing around a first axis, and is provided so as to swing around a second axis orthogonal to the first axis.
The angle estimating unit (28) is configured to scan the laser light around the first axis and the laser light around the second axis based on a light receiving signal output from the light receiving element (6). The optical scanning device according to claim 1, wherein the scanning angle is estimated. One of claims 1, characterized in that with a pre-Symbol intensity estimating unit that estimates an intensity of the laser light based on the received light intensity of 0 order transmitted diffracted light output from the light receiving element (23) 4 The optical scanning device according to claim 1.   The light according to any one of claims 1 to 5, wherein at least a part of a control circuit (23) for controlling an optical scanning device is provided on the semiconductor substrate provided with the light receiving element (6). Scanning device.

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