JP5640741B2 - Two-dimensional optical scanning device and optical scanning image display device - Google Patents

Description

  The present invention provides a two-dimensional scanning device that reciprocally scans a light beam two-dimensionally with an optical mirror that vibrates at a predetermined frequency in first and second directions, and input image data using the two-dimensional scanning device. The present invention relates to an optical scanning type image display apparatus that projects an image on a screen by guiding and scanning a light beam modulated accordingly.

  One of the image display technologies is a method of projecting and displaying an image on a screen by two-dimensionally scanning a light beam modulated according to input image data.

  In this type of image display technology, a combination of a rotating polygon mirror and a galvano mirror that moves in synchronization with the rotating mirror has been generally used, but in recent years, it has been manufactured by a microfabrication process using semiconductor manufacturing technology. A so-called MEMS (micro electro mechanical system) scanner capable of two-dimensional optical scanning is realized, and an ultra-compact image display device such as a built-in portable information terminal or a spectacle type has actually appeared.

  As a conventional example of such an optical scanning image display device, for example, there is one described in Patent Document 1. This uses a two-dimensional scanner that vibrates in a sine wave or a mode close to it in the horizontal and vertical directions, respectively, and guides the light beam modulated according to the input image data to the screen. To display a desired image.

  However, in such an image display device using a two-dimensional scanner, if the phase relationship between the amplitudes in the horizontal direction and the vertical direction is not appropriate, a desired light beam scanning locus cannot be obtained, and the quality of the display image is deteriorated. Problems arise. Specifically, mechanical vibration parts such as a MEMS scanner generally change in characteristics depending on temperature and other environmental factors, thereby changing the phase of the amplitude and adversely affecting the displayed image. Accordingly, it is actually necessary to detect the phase relationship between the amplitudes in the horizontal direction and the vertical direction and correct the phase relationship so as to maintain an appropriate phase relationship. However, Patent Document 1 does not disclose such matters at all. .

  On the other hand, for example, Patent Document 2 discloses a scanner in a two-dimensional scanner apparatus that scans a light beam in a two-dimensional direction by vibrating a mirror unit in a horizontal direction and a vertical direction in a sine wave or a mode close thereto. The unit is provided with means for converting the stress associated with the vibration of the mirror part into an electrical signal using a piezoelectric element or the like, and the detection signal is separated into signals corresponding to the resonance frequencies in the horizontal and vertical directions, Based on each signal, the resonance frequency and amplitude are controlled in each of the horizontal and vertical directions, and the mirror unit operates at a predetermined scanning angle even if the resonance frequency of the vibration system of the scanner unit changes due to changes in the usage environment. Techniques for making them disclosed are disclosed.

  However, this prior art does not consider detecting the phase relationship between the horizontal and vertical amplitudes, and if the phase relationship between the two changes, there is a problem that the quality of the display image deteriorates. It is not solved.

  For example, Patent Document 3 discloses an apparatus that displays a desired image by scanning a screen surface with a Lissajous or a locus close thereto using a two-dimensional scanner that vibrates in a sine wave or a mode close thereto in the horizontal direction and the vertical direction, respectively. Discloses a method of appropriately controlling the phase relationship between the horizontal and vertical amplitudes. However, this prior art has a light receiving means on a screen surface or the like away from the scanner, and detects the timing of the scanning light received by the light receiving means, so that the phase relationship between the horizontal and vertical amplitudes is properly adjusted. There is a problem that the apparatus is increased in size and costs are increased.

  The present invention has been made in view of the above-mentioned problems of the prior art, and in a two-dimensional optical scanning apparatus that reciprocally scans a light beam two-dimensionally with an optical mirror that vibrates at first and second predetermined frequencies, An object of the present invention is to provide a small-sized and low-cost two-dimensional optical scanning apparatus capable of optimally controlling the phase relationship of two-dimensional scanning and obtaining a desired scanning locus with high accuracy.

  Another object of the present invention is to provide an optical scanning image display device which is provided with the two-dimensional optical scanning device and can always obtain a good display image quality with an optimum desired scanning trajectory, and which is small in size and has low power consumption. is there.

  The two-dimensional optical scanning device of the present invention vibrates so as to reciprocately scan the light beam at the first frequency in the first direction by applying the drive signal having the first frequency, and at the same time, the first synchronized with the vibration. The first optical scanning means for outputting the synchronizing signal and the driving signal having the second frequency lower than the first frequency are applied to reciprocate the light beam at the second frequency in the second direction. A second optical scanning unit that vibrates as much as possible and outputs a second synchronizing signal synchronized with the vibration, and a phase detecting unit that detects a phase relationship between the first synchronizing signal and the second synchronizing signal; And a phase control means for controlling the phase of the first or second drive signal based on the phase relationship detected by the phase detection means.

  The phase detection means detects a phase difference between the first synchronization signal and the second synchronization signal at a predetermined timing within one frame period in which the phase relationship between the first scan and the second scan makes a round. Features. Specifically, in one frame period, the first scanning unit performs the reciprocating scanning in the first direction with respect to the timing at which the second optical scanning unit is substantially at the center of the reciprocating scanning in the second direction. A difference in timing at the approximate center is detected as the phase difference.

  The phase detection means detects the phase difference over n frame periods (where n is an integer equal to or greater than 2), statistically processes the detected n phase differences, and outputs the result as a first synchronization signal. And a second synchronization signal as a phase difference. For example, an average value of n detected phase differences is obtained.

  The phase control means controls the phase of the first or second drive signal so that the detected phase difference falls within a predetermined range.

  In the two-dimensional optical scanning device of the present invention, the phases of the first and second synchronization signals input to the phase detection unit appropriately correspond to the actual vibration phases of the first and second optical scanning units, respectively. It is further characterized by further comprising an adjusting means for adjusting so as to.

  An optical scanning type image display apparatus according to the present invention includes the above-described two-dimensional optical scanning apparatus, receives an image signal, and modulates the intensity of the light beam based on the image signal in synchronization with the movement of the first and second optical scanning means. In addition, a means for displaying a desired image by scanning the screen surface is provided.

  According to the two-dimensional optical scanning device of the present invention, the scanner itself is provided with means for outputting a synchronization signal indicating the state of the two-dimensional scanning, and the phase relationship of the two-dimensional scanning is optimally controlled based on the synchronization signal. Therefore, a desired scanning trajectory can be obtained with high accuracy, and a small size and low cost can be realized. Further, the first and second timings are determined at a predetermined timing within one frame period in which the phase relationship of the two-dimensional scanning is completed, for example, at the timing when both the scanning in the first direction and the scanning in the second direction pass near the amplitude center. By detecting the phase difference between the two synchronization signals, the phase relationship of the two-dimensional scanning can be detected with high accuracy, and high detection accuracy can be easily realized. Note that further operational effects of the two-dimensional optical scanning device of the present invention will become apparent from the description of embodiments described later.

  According to the optical scanning image display device of the present invention, by providing such a two-dimensional optical scanning device, optimal and good image quality can always be obtained while being small and low power consumption.

1 is a schematic block diagram of an embodiment of a two-dimensional optical scanning device of the present invention. It is the figure which showed the timing chart of the main signal in FIG. It is a schematic perspective view of the specific structural example of the MEMS scanner in FIG. It is a flowchart explaining the operation | movement of one Example of the phase detection part in FIG. FIG. 2 is a schematic block diagram illustrating a configuration example of a delay unit in FIG. 1. It is the figure which showed the timing chart of the main signal of the delay part of FIG. 5, and a phase control part. It is the figure which showed the phase relationship of the vibration of a MEMS scanner, and the relationship of a beam scanning locus | trajectory (normal case). It is the figure which showed the phase relationship of the vibration of a MEMS scanner, and the relationship of a beam scanning locus | trajectory (the case where it has shifted | deviated). It is the figure which showed the phase relationship of the vibration of a MEMS scanner, and the relationship of a beam scanning locus | trajectory (the case where it has shifted | deviated similarly).

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a block diagram schematically showing an embodiment of a two-dimensional optical scanning apparatus according to the present invention. FIG. 2 is an example of a timing chart of each signal for explaining the operation of the two-dimensional optical scanning apparatus. FIG.

  The drive signal generator 1 generates a first scan (horizontal) direction drive signal Sx and a second scan (vertical) direction drive signal Sy that are the basis of voltages Vx and Vy for driving the MEMS scanner 10 described later ( (A), (c) of FIG. Here, the frequency (second frequency) of the drive signal Sy is set lower than the frequency (first frequency) of the drive signal Sx. In the embodiment, it is assumed that the frequencies of the drive signal Sx and the drive signal Sy have a 9-to-2 relationship.

  The phase of the drive signal Sx is appropriately delayed by the delay unit 2 controlled by the phase control unit 14 described later, and is output as the signal dSx ((b) in FIG. 2). Here, the delay unit 2 and the phase control unit 14 function as phase control means.

  The drive signals dSx and Sy are appropriately amplified by the amplification circuits 3-1 and 3-2, respectively, and further filtered in some cases, and the first scan (horizontal) direction drive voltage Vx and the second scan (vertical). ) Direction drive voltage Vy is output ((d) of FIG. 2). Here, Vc1 in FIG. 2D indicates the amplitude center voltage of Vx and Vy.

  Display data (image data) is sequentially written into the frame memory 4. The data read control unit 5 generates a read address of the frame memory 4 based on the signals dSx and Sy, and sequentially reads and outputs the display data LDD from the frame memory 4. The display data LDD is converted into an analog signal LDA by the D / A converter 6, and further appropriately amplified by the amplifier circuit 7, and output as the display signal LDV. The laser unit 8 outputs a laser light beam 9 that is optically modulated based on the display signal LDV.

  The MEMS scanner 10 includes a mirror unit 101 that is driven by driving voltages Vx and Vy and vibrates two-dimensionally. The light beam 9 output from the laser unit 8 is incident on the mirror unit 101, and the light beam 9 Is reciprocated in the x direction of the scanning region and simultaneously reciprocated in the y direction. Since the frequencies of the drive voltages Vx and Vy correspond to the drive signals Sx and Sy and have a 9-to-2 relationship in this embodiment, the mirror unit 101 vibrates in the y direction for two cycles. The light beam scanning is completed by oscillating 9 cycles. This indicates one frame period.

  Further, the MEMS scanner 10 outputs a synchronization detection signal Px synchronized with the vibration of the mirror unit 101 in the x-direction reciprocating scanning and a synchronization detection signal Py synchronized with the vibration in the y-direction reciprocating scanning ((e) in FIG. 2). These synchronization detection signals Px and Py have sinusoidal signal waveforms that coincide with the respective vibration modes when the mirror unit 101 vibrates in the X-axis direction and the Y-axis direction in a resonance mode or a mode close thereto. Vc2 in FIG. 2 (e) indicates the amplitude center voltage of Px and Py.

  FIG. 3 schematically shows a configuration example of the MEMS scanner 10 suitable for the present invention. In FIG. 3, the MEMS scanner 10 has a mirror part 101 having a light reflecting surface formed on the surface, and the mirror part 101 is paired with a first pair of first torsion bars 102a and 102b. It is supported by the beams 103a and 103b. Specifically, one ends of the first torsion bars 102a and 102b are respectively connected to both sides of the mirror part 101 so as to be connected to each other by a line passing through the approximate center of the mirror part 101. The other end of 102b opposite to the mirror part 101 is connected to a substantially central part of the pair of support beams 103a and 103b, and both ends of the first support beams 103a and 103b are end parts inside the movable frame 111, respectively. It is connected to the. The first driving piezoelectric members 104a1, 104a2, 104b1, 104b2 and the first detecting piezoelectric members 105a1, 105a2, 105b1, 105b2 are provided on the first support beams 103a, 103b, respectively.

  On the other hand, the movable frame 111 is supported by a pair of second support beams 113a and 113b via a pair of second torsion bars 112a and 112b. Specifically, the second torsion bars 112a and 112b are arranged so as to pass through substantially the center of the mirror portion 101 and substantially perpendicular to the axes of the first torsion bars 102a and 102b, and one end of each of them is movable frame 111. The other end of each of the second support beams 113a and 113b is connected to a substantially central portion of each of the second support beams 113a and 113b. It is connected. Second drive piezoelectric members 114a1, 114a2, 114b1, 114b2 and second detection piezoelectric members 115a1, 115a2, 115b1, 115b2 are provided on the second support beams 113a, 113b, respectively.

  Now, when a voltage having the same phase is applied to the first driving piezoelectric members 104a1 and 104b1 and the opposite direction is applied to the first driving piezoelectric members 104a1 and 104b2 by the driving voltage Vx, the first support beams 103a and 103b are strained in opposite directions (elongation and extension). (Shrinkage) occurs, the first torsion bars 102a and 102b are twisted, and the mirror portion 101 performs a reciprocating resonance around the axis of the first torsion bars 102a and 102b. In this case, the MEMS scanner 10 functions as a first optical scanning unit, and reciprocally scans the incident light beam in the x direction as the first direction of the scanning region.

  At the same time, when the same voltage is applied to the second driving piezoelectric members 114a1 and 114b1 and the opposite direction is applied to the second driving piezoelectric members 114a1 and 114b2 by the driving voltage Vy, the second support beams 113a and 113b are similarly distorted in the opposite directions. Occurs, the second torsion bars 112a and 112b are twisted, and the movable frame 110 resonates reciprocally around the axes of the second torsion bars 112a and 112b. Resonant reciprocating motion is performed around the axes of the torsion bars 112a and 112b. In this case, the MEMS scanner 10 functions as a second light scanning unit, and reciprocates the incident light beam in the y direction as the second direction of the scanning region.

  On the other hand, when the first support beams 103a and 103b are distorted, the first detection piezoelectric members 105a1, 105a2, 105b1 and 105b2 are also distorted, and voltages corresponding to the respective strain changes are generated. Therefore, the electrodes of the first piezoelectric materials for detection 105a1, 105a2, 105b1, and 105b2 are connected so that the voltages generated from each other are in phase, thereby synchronizing in synchronization with the vibration of the mirror unit 101 in the x-direction reciprocating scanning. The detection signal Px can be taken out. Similarly, when the second support beams 113a and 113b are distorted, the second detection piezoelectric members 115a1, 115a2, 115b1 and 115b2 are also distorted, and voltages corresponding to changes in the distortion are generated. Accordingly, the electrodes of the second detection piezoelectric members 115a1, 115a2, 115b1, and 115b2 are connected so that the generated voltages are in phase with each other, thereby synchronizing detection in synchronization with the vibration of the mirror unit 101 in the y-direction reciprocating scanning. The signal py can be taken out. The synchronization detection signals Px and Py correspond to changes in the drive voltages Vx and Vy and take sinusoidal signal waveforms ((d) and (e) in FIG. 2).

  Returning to FIG. 1, the synchronization detection signals Px and Py are appropriately amplified by the amplifier circuits 11-1 and 11-2, respectively, and output as voltage signals VPx and VPy ((f) in FIG. 2). Vc3 in FIG. 2F indicates the amplitude center voltage of VPx and VPy. T0 indicates the approximate center of reciprocal scanning in the y direction.

  The voltage signals VPx and Vpy are binarized by the comparators 12-1 and 12-2, respectively ((g) and (h) in FIG. 2). The threshold for binarization is preferably set at or near the amplitude center Vc3 of the voltage signals VPx and VPy. Thereby, since binarization is performed at the earliest timing of signal change, it is possible to suppress the occurrence of jitter.

  As described above, in this embodiment, while the MEMS scanner 10 (mirror unit 101) vibrates for two cycles in the y direction, the light beam scanning makes a round by vibrating for nine cycles in the x direction. That is, in this case, one frame period is a time for which the MEMS scanner 10 vibrates for two cycles in the y direction.

  The phase detector 13 first detects one frame period by counting the synchronization signal DPy for two cycles. Then, by measuring the first rising (or falling) transition of the synchronizing signal DPx with respect to a specific rising (or falling) transition of the synchronizing signal DPy within one frame period, the phase difference TPxy between the synchronizing signals DPx and DPy. Is detected ((i) in FIG. 2). Preferably, in one frame period, the timing at which the first pulse of the synchronization signal DPx arrives (MEMS) with respect to the timing at which the synchronization signal DPy reaches approximately T0 (timing at which the MEMS scanner 10 is approximately at the center of reciprocal scanning in the y direction). The difference between the timing at which the scanner 10 comes to the approximate center of the reciprocating scanning in the x direction is detected. That is, the phase difference TPxy between the synchronization signals DPx and Dpy is detected at the timing when both the scanning in the x direction and the scanning in the y direction pass near the center of the scanning region. In this case, the phase relationship between Dpx and Dpy can be detected with high accuracy, and high detection accuracy can be easily realized.

  Although omitted in FIG. 1, the phases of the synchronization signals DPx and DPy input to the phase detector 13 are adjusted so as to appropriately correspond to the actual vibration phases of the MEMS scanner 10 in the x and y directions, respectively. Adjustment means may be further provided. That is, the synchronization signals DPx and DPy may include errors that cannot be ignored with respect to the actual scanning phase due to the influence of the delay characteristics of the respective transmission paths. By providing the adjusting means, even if such an error occurs, it is possible to control the phase relationship of two-dimensional scanning described later appropriately and with higher accuracy by correcting the error.

  If the phase difference TPxy output from the phase detector 13 exceeds a predetermined range, the phase controller 14 outputs a control signal RST_T and correction data TC to correct it. If the phase difference TPxy is within the predetermined range, neither the control signal RST_T nor the correction data TC is output. When receiving the control signal RST_T, the delay unit 2 controls the phase of the drive signal Sx according to the correction data TC and outputs it as a signal dSx. As a result, the phase relationship between Sx and Sy, that is, Vx and Vy is controlled so that scanning in the x direction and y direction in the MEMS scanner 10 has a desired phase relationship. That is, the phase difference is controlled so as to fall within a predetermined range.

  FIG. 4 is a flowchart schematically showing an example of the operation of the phase detector 13. First, one frame period is detected by counting the synchronization signal DPy for two cycles (step 1001). Thereafter, when the rising of the synchronization signal DPy is detected in approximately half of one frame period (YES in step 1002), the internal timer 1 (not shown) is started to start counting up, and at the same time, the value of the polarity code SIGN is changed to “ 0 "(step 1003). Here, the count value of the timer 1 represents the phase difference TPxy, and SIGN represents its polarity (delay, advance). Here, when SIGN = 0, TPxy is positive (delayed), and when SIGN = 1, TPxy is negative (advanced). Of course, there is no problem even if the reverse is true.

  After the count-up of the timer 1 is started, it is determined whether or not the rising of the synchronization signal DPx is detected before the count value TPxy reaches the ½ cycle period of the drive signal Sx (steps 1004 and 1005). Here, when the rising edge of the synchronization signal DPx is detected before the count value TPxy of the timer 1 reaches the ½ period period of the drive signal Sx (NO in step 1004, YES in step 1005), the timer at that time 1 is stopped (step 1008), and the count value TPxy at that time is output as phase difference data together with the polarity code SIGN (0) (step 1009). That is, in this case, the MEMS scanner 10 represents that the phase of vibration in the X-axis direction is delayed by TPxy with respect to the phase of vibration in the Y-axis direction.

  If the rising edge of the synchronization signal DPx is not detected even when the count value TPxy of the timer 1 reaches the ½ period period of the drive signal Sx (YES in step 1004), the count operation of the timer 1 is switched to countdown. The countdown operation is started from the count value TPxy (the value of the half period of Sx), and at the same time, the value of the polarity code SIGN is set to “1” (step 1006). Then, it is determined whether the rising edge of the periodic signal DPx is detected before the count value TPxy of the timer 1 becomes 0 (steps 1007 and 1005).

  If the rising edge of the synchronization signal DPx is detected before the count value TPxy becomes 0 after the timer 1 starts the countdown operation (NO in step 1007 and YES in step 1005), the timer 1 counts down at that time. The operation is stopped (step 1008), and the count value TPxy at that time is output as phase difference data together with the polarity code SIGN (1) (step 1009). That is, in this case, in the MEMS scanner 10, the phase of vibration in the X-axis direction is advanced by TPxy with respect to the phase of vibration in the Y-axis direction.

  When the timer 1 starts the countdown operation and the synchronization signal DPx is not detected even when the count value TPxy becomes 0 (YES in Step 1007), the count operation of the timer 1 is stopped at that time (Step 1008). ), The count value TPxy = 0 at that time is output together with the polarity code SIGN (1) (step 1009). That is, in this case, there is no phase difference between the synchronization signals DPx and DPy.

  Thereafter, the polarity code SIGN and the count value TRxy are reset (step 1010). When the next rising edge of the synchronization signal DPy is detected (step 1011), the operation in the current frame period is ended, and the same operation in the next frame is prepared.

  The phase detector 13 performs the operation of detecting the phase difference between the synchronization signals DPx and DPY over an n frame period (n is an integer of 2 or more), and statistically processes the detected n phase differences (for example, The average value of n phase differences is obtained), and the value may be output as phase difference data of the synchronization signals DPx and DPy. As a result, even if there is jitter due to noise or the like in the synchronization signal, the influence can be removed, and highly accurate and stable detection performance can be obtained.

  The phase control unit 14 outputs the control signal RST_T and the correction data TC based on the count value TPxy and the polarity code SIGN which are phase difference data between the synchronization signals DPx and DPy output from the phase detection unit 13. As described above, the phase control unit 14 outputs the control signal RST_T and the correction data TC if TPxy exceeds the predetermined range, and outputs either RST_T or TC if TRxy is within the predetermined range. do not do. When receiving the control signal RST_T, the delay unit 2 controls the phase of the drive signal Sx based on the correction data TC and outputs a signal dSx.

  FIG. 5 schematically shows a configuration example of the delay unit 2. FIG. 6 shows an example of a timing chart of each signal for explaining operations of the delay unit 2 and the phase control unit 14 based on the configuration example of FIG.

  When the count value TPxy that is the phase difference data exceeds the predetermined range, the phase control unit 14 sets the control signal RST_T to low (L) and outputs the correction data TC (FIGS. 6A and 6B). ), (C)). The control signal RST_T then returns to high (H).

  The delay unit 2 includes a timer (internal timer 2) 201 and an oscillation circuit 202. When the control signal OSC_EN from the timer 201 is high (H), the oscillation circuit 202 oscillates at exactly the same frequency as the drive signal Sx. The timer 201 normally sets the control signal OSC_EN to high (H), but when the control signal RST_T from the phase control unit 14 becomes low (L), the control signal OSC_EN is set to low (L) (FIG. 6). (D)), a reset state is entered. Then, at the timing when the control signal RST_T from the phase control unit 14 becomes high (H), the timer 201 captures and holds the correction data TC, and then synchronizes with the rising edge of the drive signal Sx detected first. When the count starts and the time Td corresponding to the correction data TC is counted, the control signal OSC_EN is set to high (H) ((d), (f) in FIG. 6). The transmission circuit 202 temporarily stops oscillation when the control signal OSN_EN from the timer 201 becomes low (L), and synchronizes with the drive signal Sx when the control signal OSN_EN rises from low (L) to high (H). Oscillation is resumed at exactly the same frequency and the signal dSx is output ((e) of FIG. 6).

  As can be seen from FIG. 6, the phase of the signal dSx with respect to the drive signal Sx can be delayed or advanced in accordance with the value of the time Td. That is, the phase relationship between the x direction and the y direction in the MEMS scanner 10 can be corrected according to the phase difference between the synchronization signals VPx and Vpy.

  As described above, in this embodiment, the MEMS scanner 10 oscillates nine cycles in the x direction while the MEMS scanner 10 oscillates two cycles in the y direction. 7, 8, and 9 show the relationship between the horizontal phase and vertical vibration phase relationships and the beam scanning trajectory in this case. In each figure, (a) shows the phase relationship between the synchronization signals VPx and VPy (phase relationship of vibrations in the x and y directions of the MEMS scanner) at a predetermined timing (substantially the center of scanning) T0 with respect to (f) in FIG. The figure expanded and shown to the axial direction, (b) is the figure which showed the beam scanning locus | trajectory in that case.

  FIG. 7 shows a case where the phase relationship between the vibrations in the x and y directions coincides in one frame period, and a scanning trajectory with a uniform density is obtained over the entire scanning surface. On the other hand, FIGS. 8 and 9 show the case where the phase relationship between the vibrations in the x direction and the y direction is shifted, and in this case, the density of the scanning lines is uneven. The scanning trajectory of FIG. 7 is preferable in the optical scanning image apparatus that scans the light beam with the MEMS scanner and displays the image on the screen surface. In the present embodiment, the optical scanning image apparatus of FIG. Such a desired scanning trajectory is obtained with high accuracy, and good image quality is realized.

  As mentioned above, although one Embodiment of this invention was described, this invention is not limited to the form demonstrated so far. For example, in the configuration of FIG. 1, the phase of the drive signal Sx is controlled, but the phase of the drive signal Sy may be controlled. Further, the delay unit need not have the configuration shown in FIG. It is sufficient that the phase of the drive signal Sx or Sy can be controlled based on the detected phase relationship, and the specific configuration is not limited.

DESCRIPTION OF SYMBOLS 1 Drive signal production | generation part 2 Delay part 3-1, 3-2 Amplification circuit 4 Frame memory 5 Data read-out control part 6 D / A converter 7 Amplification circuit 8 Laser unit 10 MEMS scanner 11-1, 11-2 Amplification circuit 12 -1,12-2 Comparator 13 Phase detector 14 Phase controller

JP 2005-526289 A JP-A-9-101474 JP 2010-164955 A

Claims (6)

By applying a drive signal having a first frequency, the first beam is vibrated to reciprocate and scan the light beam at the first frequency in the first direction, and at the same time, a first synchronization signal synchronized with the vibration is output. a scanning means, in said second frequency in a second direction by applying a driving signal of a second frequency lower than the first frequency when you vibrate so as to reciprocally scan the light beam at the same time, the In a two-dimensional optical scanning device comprising a second optical scanning means for outputting a second synchronization signal synchronized with vibration,
Phase detecting means for detecting the phase relationship between the first synchronizing signal and the second synchronizing signal, and controlling the phase of the first or second driving signal based on the phase relationship detected by the phase detecting means. Provide phase control means ,
The phase detection means detects a phase difference between the first synchronization signal and the second synchronization signal at a predetermined timing within one frame period in which the phase relationship between the first scan and the second scan makes a round. ,
The phase detection means detects the phase difference over n frame periods (where n is an integer of 2 or more), statistically processes the detected n phase differences, and outputs the result as the first synchronization. A two-dimensional optical scanning device that outputs a phase difference between a signal and a second synchronization signal . In the one frame period, the phase detection unit is configured such that the first optical scanning unit is the first optical unit with respect to a timing at which the second optical scanning unit is substantially at the center of the reciprocating scanning in the second direction. The two-dimensional optical scanning device according to claim 1, wherein a difference in timing at a substantially center of reciprocal scanning in a direction is detected as the phase difference . The statistical processing, two-dimensional optical scanning apparatus according to claim 1 or claim 2, wherein the process der Rukoto obtaining an average value of the detected n pieces of phase difference. It said phase control means so that the detected phase difference is within a predetermined range, any of claims 1 to 3, characterized in that to control the first or the phase of the second driving signal The two-dimensional optical scanning device according to claim 1. Adjustment means for adjusting the phases of the first and second synchronization signals input to the phase detection means so as to appropriately correspond to the phases of actual vibrations of the first and second optical scanning means, respectively. two-dimensional optical scanning apparatus according to any one of claims 1 to 4, characterized in that the. 4. The two-dimensional optical scanning device according to claim 1, wherein an image signal is input and the light beam is transmitted in synchronization with movements of the first and second optical scanning units. An optical scanning type image display apparatus comprising means for displaying a desired image by scanning a screen surface while intensity-modulating based on a signal .

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