JP5585064B2 - Two-dimensional optical scanning device and optical scanning image display device - Google Patents

Description

  The present invention is a two-dimensional optical scanning device provided with a light beam scanning means that vibrates at a predetermined frequency in each of the first and second directions, and is modulated according to input pixel data using the two-dimensional optical scanning device. The present invention relates to an optical scanning type image display apparatus that forms an image on a screen by guiding and scanning a light beam to the screen.

As one of image display technologies, there is an optical scanning method in which an image is formed on a screen by guiding and scanning a light beam modulated according to input pixel data to the screen.
Conventionally, an optical scanning type (or optical scanning type) image display device is generally a combination of a rotating polygon mirror and a galvanometer mirror that moves in synchronization with the rotating mirror. A so-called MEMS scanner that is extremely small and capable of two-dimensional optical scanning has been realized, and an ultra-compact image display device such as a built-in portable information terminal or a glasses type has actually appeared.

As a conventional example of such an optical scanning image display device, a device described in Patent Document 1 is known.
The technique described in Patent Document 1 is an apparatus for displaying a desired image by scanning a screen surface with a trajectory 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. And a method.
However, as described in the specification of Patent Document 1, in an image display apparatus using such a two-dimensional scanner, desired beam scanning is performed unless the phase relationship between the horizontal and vertical amplitudes is appropriate. There is a problem that the trajectory cannot be obtained and the image quality deteriorates.
Specifically, for mechanical vibration parts such as a MEMS scanner, the characteristics generally change over time due to environmental factors such as temperature characteristics, and the amplitude phase may also change accordingly.
Therefore, in practice, the phase relationship between the horizontal and vertical amplitudes must be detected and corrected to an appropriate phase relationship as necessary.

As a conventional technique for detecting the phase relationship between the horizontal direction and the vertical direction, there is, for example, Patent Document 2.
These are intended to detect the attitude of a movable member that can be angularly displaced around a predetermined axis by using an induced electromotive force. In other words, a loop-shaped speed detection coil is formed on the movable member and placed in a static magnetic field. When the movable member is angularly displaced, the magnetic flux passing through the region surrounded by the speed detection coil of the movable member changes and is guided. An electromotive force is generated, and the angular displacement of the movable member can be measured by measuring the magnitude of the induced electromotive force.
Another conventional technique for detecting the phase relationship between the horizontal direction and the vertical direction is, for example, Patent Document 3.
These are intended to detect the posture of the movable member by converting the stress accompanying the vibration of the movable member into an electrical signal using a piezoelectric element or the like and taking it out.

However, the method described in Patent Document 2 has a complicated configuration, and there is a problem that the size and cost of the apparatus cannot be reduced depending on the application. Moreover, when arrange | positioning and using in a predetermined magnetic field, the magnetic field of the place where a movable member is arrange | positioned changes.
When the magnetic field at the place where the movable member is arranged changes, the magnetic flux in the region surrounded by the loop-shaped speed detection coil formed on the movable member changes. Therefore, the magnitude of the induced electromotive force generated by the angular displacement of the movable member also changes, and there is a problem that the angular displacement amount of the movable member cannot be accurately detected. For example, when the optical scanning device is placed in a magnetic field in which the magnetic flux in the region surrounded by the loop-shaped speed detection coil formed on the movable member is zero, an induced electromotive force is generated even if the movable member is angularly displaced. Therefore, it becomes impossible to detect the angular displacement amount of the movable member.

Further, in the method as described in Patent Document 3, a detected electric signal is weak, and in order to obtain sufficient detection accuracy, a detection circuit having a high S / N ratio and a high amplification factor is required. However, there is a problem that it becomes complicated and large in size and high in cost.
In addition to this, as another prior art for detecting the phase relationship between the horizontal direction and the vertical direction, for example, as in Patent Document 4, the movable member and the member that supports it are opposed to each other. There are several methods, such as a method of detecting the capacitance change of the capacitor due to the vibration of the movable member by providing an electrode, and any method has a weak electric signal, and the same as described above. There is a problem.

The present invention has been made in view of such circumstances, and the main object of the present invention is to provide a two-dimensional optical scanning device that can detect a phase shift between amplitudes in the horizontal and vertical directions with high accuracy and maintain high image quality. With a purpose.
In addition, the present invention can detect the phase shift of the amplitude in the horizontal direction and the vertical direction with high accuracy without being affected by the environment in which the apparatus is placed, can maintain high image quality, and has a simple configuration, small size and low cost. The main purpose is to provide a two-dimensional optical scanning device.

In order to achieve the above object, according to the first aspect of the present invention, the first vibration that vibrates to reciprocate the light beam at the first frequency in the first direction by applying a signal having the first frequency. And a second optical scanning that vibrates to reciprocately scan the light beam at the second frequency in the second direction by applying a signal having a second frequency different from the first frequency. And two or more adjacent to each other outside an effective scanning area in at least one of the first and second scanning directions, the first and second light receiving means for receiving pre climate beams of second light scanning unit acquires the light reception time in each light receiving unit in reflection of the light beam, said first and second optical scanning based on these light reception time means of the vibration of the A phase detection means for detecting a phase deviation, characterized in that the provided.

According to a second aspect of the present invention, in the two-dimensional optical scanning device according to the first aspect , the light receiving means is arranged in a scanning direction having a higher frequency in the first or second scanning direction. It is characterized by that.
According to a third aspect of the present invention, in the two-dimensional optical scanning device according to the first or second aspect , the phase shift of the vibrations of the first and second optical scanning units detected by the phase detecting unit is predetermined. It has a phase correcting means for correcting within the range .

According to a fourth aspect of the present invention, in the two-dimensional optical scanning device according to the third aspect , the phase correction means has a phase shift of vibrations of the first and second optical scanning means within a predetermined range. Thus, the phase relationship between the signal of the first frequency and the signal of the second frequency is controlled .
The invention according to claim 5 is characterized in that.

According to a sixth aspect of the present invention, in the two-dimensional optical scanning device according to the third or fourth aspect , when the light beam is received by only one light receiving unit , the phase correcting unit receives two or more light receiving units. The pre-stage correction is performed so that the light is received by the means, and then the phase shift of the vibrations of the first and second optical scanning means detected by the phase detection means is corrected within a predetermined range. .
According to a seventh aspect of the present invention, in the two-dimensional optical scanning device according to the sixth aspect , the light receiving means is divided into a first group and a second group along the scanning direction with the low frequency, and the phase The detecting means obtains the light receiving time 1 of the light beam in the entire first group and the light receiving time 2 of the light beam in the entire second group, and based on the comparison result, It is characterized by detecting a phase shift of vibrations of the first and second optical scanning means .

According to an eighth aspect of the present invention, in the two-dimensional optical scanning apparatus according to the seventh aspect, the light reception time 1 or 2 is received by the entire light receiving means of the first group. The total time is 1 and the total light receiving time of the light beam detected by the entire light receiving means of the second group is 2, and the phase detecting means scans in one direction with respect to the low frequency scanning direction. A difference value of a total of 1 and 2 of the light receiving times is obtained for every part or all of the periods during the period, and the phase shift of the vibration of the first and second optical scanning means is obtained based on the result. It is characterized by detecting .
According to a ninth aspect of the present invention, in the two-dimensional optical scanning device according to the eighth aspect, the phase shift of the vibrations of the first and second optical scanning means detected by the phase detecting means is within a predetermined range. The phase correction means corrects the difference between the total of 1 and 2 of the light reception times acquired in one frame period in which the phase relationship between the first scan and the second scan makes a round. Among these, the phase shift of the vibration of the first and second optical scanning means is corrected so that at least one falls within a predetermined range .

According to a tenth aspect of the present invention, in the two-dimensional optical scanning device according to any one of the sixth to ninth aspects, the light-receiving unit is configured such that the light receiving unit has the boundary of the scanning range in the scanning direction with the low frequency as a boundary. It is divided into the 1st and 2nd group, and is arrange | positioned so that it may become mutually symmetrical .
According to an eleventh aspect of the present invention, in the two-dimensional optical scanning device according to any one of the first to tenth aspects, the light receiving means is an apparatus casing having the first and second optical scanning means. It is provided .

According to a twelfth aspect of the present invention, the optical scanning image display device includes the two-dimensional optical scanning device according to any one of the first to eleventh aspects, wherein an image signal is input and the first and second are input. A means for displaying a desired image by scanning the screen surface while modulating the intensity of the light beam based on the image signal in synchronization with the movement of the light scanning means is provided .

According to the present invention, the light beam scanning state is directly detected by the light receiving means to grasp the amplitude phase relationship (phase shift state) of the first and second light scanning means, and when there is a phase shift, Since the correction is made, the phase relationship between the scanning amplitudes in the two directions can be detected easily and with high accuracy, so that a desired scanning locus can be made with high accuracy and high image quality can be realized.
In addition, since a plurality of amplitude timing information in the scanning direction on the higher frequency side is acquired and processed comprehensively within a predetermined period in the scanning direction on the lower frequency side, detection accuracy can be obtained with a single light reception timing signal. Even in such a case, it is possible to detect the phase relationship between the scanning amplitudes in the two directions easily and with high accuracy, so that a desired scanning locus can be realized with high accuracy.
Since the phase relationship between the scanning amplitudes in the two directions is always optimally automatically corrected, the convenience can be improved without bothering the user.

1 is a schematic configuration diagram of an optical scanning image display device according to a first embodiment of the present invention. It is a perspective view of the MEMS scanner which has a 1st optical scanning means and a 2nd optical scanning means together. It is a figure which shows the Lissajous pattern by a two-dimensional optical scanning device. It is a figure which shows the detection state of the amplitude phase relationship of the 1st and 2nd optical scanning means. It is a figure which shows the detection state of the state from which the amplitude phase has shifted | deviated. It is a figure which shows the state which an amplitude phase shift | deviates and can receive light only with one light-receiving means. It is a figure which shows the arrangement pattern of a light-receiving means. It is a schematic block diagram of the optical scanning type image display apparatus which concerns on 2nd Embodiment. It is a schematic diagram which shows the Example of a data addition circuit. It is a figure in case the phase relationship of a vibration is appropriate. It is a figure which shows an example in case the phase relationship of a vibration is not suitable and a scanning locus | trajectory is non-uniform | heterogenous. It is a figure which shows the other example in case the phase relationship of a vibration is not suitable and a scanning locus | trajectory is non-uniform | heterogenous. It is a figure which shows that the density of a scanning locus changes with the arrangement | positioning locations of a light-receiving means, (a) is a figure which shows the state by which the light-receiving means is arrange | positioned at the screen side, (b) is a light-receiving means provided in the apparatus housing | casing. It is a figure which shows the state where a scanning locus | trajectory becomes dense exceeding the resolution of a light-receiving means with respect to a beam diameter.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a block diagram schematically showing a first embodiment of an optical scanning type image display device including a two-dimensional optical scanning device according to the present embodiment.
The system control circuit 1 generates pulse signals Sx and Sy as a basis of signals Vx and Vy for driving a MEMS (Micro-Electro-Mechanical Systems) scanner 4 described later, and a modulation signal for driving a laser light source 5 described later. A data signal LDD that is the basis of the LDV is generated and output.
The pulse signal Sx, which is a signal having the first frequency, is appropriately delayed by a delay circuit 2 controlled by a data processing circuit 11 to be described later and output as a pulse signal dSh.
The pulse signal dSh and the signal Sy of the second frequency are appropriately amplified by the amplifier circuits 3x and 3y, respectively, further filtered in some cases, and output as drive signals Vx and Vy.

The data signal LDD is converted into an analog signal LDA by the D / A converter 6 and further appropriately amplified by the amplifier circuit 13 and output as the modulation signal LDV. The laser light source 5 outputs a light beam 12 that is modulated light based on the modulation signal LDV.
The MEMS scanner 4 as a scanning means is driven by a drive signal Vx, and reciprocally scans the incident light beam 12 on the screen 16 in the x direction as the first direction of the scanning region, and at the same time, is incident by the drive signal Vy. A mirror portion that two-dimensionally vibrates so as to reciprocately scan the light beam 12 also in the y direction as the second direction of the scanning region is provided.

Photodiodes 7a and 7b as light receiving means are arranged along a second direction (y direction) at a predetermined position in a part of the scanning region, and convert the reached light beam into electric signals Pa and Pb. And output.
Here, although it is not essential, it is preferable that the light beam 12 scans a range wider than the effective scanning area originally required, and the photodiodes 7a and 7b are arranged outside the effective scanning area.
The signals Pa and Pb are respectively converted into voltage signals VPa and VPb by the amplifier circuits 8a and 8b, then binarized by the comparators 9a and 9b, and output as digital signals DPa and DPb.
The timer circuits 10a and 10b measure the periods during which the light beams are received by the photodiodes 7a and 7b based on the digital signals DPa and DPb, respectively, and output the results as data signals TDa and TDb.

The amplifier circuits 8a and 8b, the comparators 9a and 9b, and the timer circuits 10a and 10b constitute the phase detection means 15.
For example, the data processing circuit 11 as the phase correction means obtains a difference between TDa and TDb, and if the result is out of the allowable range, outputs a correction signal TC to correct it and controls the delay circuit 2 described above. The phase relationship between the pulse signals Sx and Sy is corrected so that the scanning in the x direction (first direction) and the y direction (second direction) in the MEMS scanner 4 has a desired phase relationship.

The configuration of the MEMS scanner 4 will be described with reference to FIG.
The MEMS scanner 4 has a structure in which a minute mirror 13a having a reflecting surface is supported by torsion bars 13b and 13c.
The micromirror 13a performs a reciprocating reciprocating motion about the axis 13d as the torsion bar 13b is twisted. This vibration is generated by applying a signal having a first frequency to an electrode (not shown) provided on each of the frame 13f and the micromirror 13a. In this case, the MEMS scanner 4 functions as a first optical scanning unit.
The micro mirror 13a performs a reciprocating reciprocating motion about the axis 13e by twisting the torsion bar 13c. This vibration is generated by applying a signal of a second frequency to an electrode (not shown) provided in each of the frame 13f and the frame 13g. In this case, the MEMS scanner 4 functions as a second optical scanning unit.
By the reciprocating motion about both the axes 13d and 13e, the normal direction of the deflection surface of the micromirror 13a changes two-dimensionally. For this reason, the reflection direction of the beam incident on the micromirror 13a is changed, whereby the beam can be scanned in a two-dimensional direction.

FIG. 3 shows a Lissajous pattern by a two-dimensional optical scanning device, where (a) shows a state where there is no amplitude phase shift, and (b) and (c) show a state where there is a phase shift in amplitude. Yes.
When there is no phase shift in amplitude, as shown in FIG. 4, the light receiving periods TDa and TDb in the photodiodes 7a and 7b are not different and are equal (TDa = TDb). The relationship between the photodiodes 7a and 7b and the scanning lines in this case is the state shown in FIG.
When the phase shift of the amplitude occurs, as shown in FIG. 5, the light receiving period in the photodiode 7a is shortened, and TDa <TDb. This makes it possible to directly detect whether or not there is a phase shift. For example, the phase shift amount can be calculated by obtaining the difference (TDb−TDa).
The data processing circuit 11 as the phase correction means outputs a correction signal TC to correct the phase shift amount calculation result outside the allowable range, and controls the delay circuit 2 to correct it. The phase relationship between the pulse signals Sx and Sy is corrected so that the scanning in the y direction has a desired phase relationship.
The allowable value of the phase shift amount is stored in advance in the memory of the data processing circuit 11, and it is determined whether to correct based on this allowable value. In the case of correction, the correction amount is automatically extracted from the data table of the relationship between the phase shift amount and the correction amount stored in advance, and the correction signal TC is generated based on the extracted value.
Although the correction in the phase shift state in which the scanning line folding position is shifted to the photodiode 7b side has been described here, the same correction can be made even when the phase shifts in the opposite direction.

The frequency of the pulse signal Sy that is the second frequency signal is higher than the frequency of the pulse signal Sx that is the first frequency signal, and as shown in FIG. 1, the folding angle of the scanning line becomes steep (acute angle). Using this characteristic, the photodiodes 7a and 7b are arranged adjacent to each other along the second direction.
Thus, if the steepness of the scanning line having a higher frequency is used, the detection area of the light receiving means can be reduced, and there is an advantage that the light receiving means can be downsized.
As shown in FIGS. 1 and 3A, the photodiodes 7a and 7b are arranged outside the effective scanning area, but are arranged in the effective scanning area on the screen 16 so as not to affect the image quality. You can also. In this case, the downsizing is advantageous from the viewpoint of suppressing the influence on the image quality.

As shown in FIG. 6, when only one of the two photodiodes 7a and 7b receives light, the difference cannot be detected by the correction method. In such a case, the data processing circuit 11 performs coarse correction in the previous stage so that light is received by the two photodiodes 7a and 7b, and when the light is received by the two photodiodes 7a and 7b. The same correction as above is performed.
A similar pre-stage correction is performed even when neither of the two photodiodes 7a and 7b receives light.

In the above embodiment, the two photodiodes 7a and 7b are arranged so as to be adjacent to each other in the second direction, but may be arranged similarly in the first direction having a low frequency.
Further, as shown in FIG. 7 (a), one photodiode 7 is arranged in the second direction, and one photodiode 20 is arranged in the first direction to constitute the light receiving means. Good.
Further, as shown in FIGS. 7B and 7C, the light receiving means may be configured by arranging two or more photodiodes in each of the first direction and the second direction.
In the above embodiment, the data processing circuit 11 automatically corrects the data. However, it may be corrected manually. In this case, the phase shift state detected by the phase detection means may be displayed, and manual adjustment may be performed while transmitting a correction signal based on the display result.

The second embodiment will be described with reference to FIGS. Parts having functions equivalent to those in the above embodiment are given the same numbers.
Including the first embodiment, the light receiving means may be provided in the apparatus casing provided with the optical scanning means, or may be provided on the screen side separately from the apparatus casing.
In order to reduce the size of the device, if the light receiving means is arranged with respect to the optical scanning means at an extremely short distance compared to the projection distance of the scanning light (for example, the distance to the screen surface in the case of an image display device), In other words, if an attempt is made to arrange, for example, between the MEMS scanner 4 and the beam transmission window of the apparatus housing provided with the optical scanning means, the scanning trajectory is detected with respect to the beam diameter, particularly in the scanning direction on the lower frequency side. There is a case in which it becomes dense beyond the resolution of (means) and it becomes difficult to accurately determine which light reception timing is the timing to be detected.
FIG. 13 shows an example of such a situation. In FIG. 13, (a) shows the relationship between the scanning trajectory illustrated in FIG. 1 of the above embodiment and the light receiving means 7a and 7b as compared with the projection distance of the scanning light with respect to the optical scanning means. The relationship between the scanning locus and the light receiving means when arranged at a distance is conceptually shown, and (b) shows the scanning locus on the light receiving surface of the actual light receiving means and the state of the light beam. .
In this embodiment, even in such a case, it is possible to detect a phase shift between amplitudes in the horizontal direction and the vertical direction with high accuracy, to maintain high image quality, and to provide a small and low-cost two-dimensional optical scanning device that is simple in configuration. It is aimed.

As shown in FIG. 8, signals Pa and Pb are converted into voltage signals VPa and VPb by amplifier circuits 8a and 8b, respectively, and then binarized by comparators 9a and 9b and output as digital signals DPa and DPb.
The timer circuits 10a and 10b measure the periods during which the light beams are received by the photodiodes 7a and 7b based on the digital signals DPa and DPb, respectively, and output the results as data signals TDa and TDb.
TDa is “total light reception time 1”, and “TDb” is “total light reception time 2”.
The photodiode 7a constitutes a first group of light receiving means, and the photodiode 7b constitutes a second group of light receiving means. Here, each of the first and second groups is constituted by one photodiode, but a plurality of each may be provided.
When the valid data discriminating circuit 22 detects that light is simultaneously received in both the photodiodes 7a and 7b, the valid data discriminating circuit 22 makes the signal DEN affirmative (for example, “H” level) and holds it. Further, when it is detected that light is not received in both the photodiodes 7a and 7b during the period when the signal DEN is “H”, the signal TEN is affirmed (for example, set to “H” level) for a certain time. The light reception period is determined when light reception stops.

The data addition circuits 21a and 21b capture the data signals TDa and TDb output from the timer circuits 10a and 10b, respectively, during the period when the signal TEN is “H”, and integrate the data into the data captured so far. The signals are held as signals TTDa and TTDb and output to the data processing circuit 11 at the subsequent stage. Therefore, the “certain time” for making the signal TEN positive is the “processing time” of the data addition circuits 21a and 21b.
When the signal TEN transitions from “H” to negative “L”, the timer circuits 10 a and 10 b initialize themselves and prepare for the next light reception. Here, “H” is used as an affirmative and “L” is used as a negative meaning.
Next, when the valid data discriminating circuit 22 detects that light is simultaneously received in both the photodiodes 7a and 7b, the signal TEN is set to “H” for a predetermined time, and the data adding circuits 21a and 21b are respectively set to timers. The data signals TDa and TDb output from the circuits 10a and 10b are captured during the period when the signal TEN is “H”, integrated with the data captured so far, and the data signals TTDa and TTDb are updated. During this time, the signal DEN holds “H”.
When the valid data discriminating circuit 22 detects that no light is received in at least one of the photodiodes 7a or 7b after a unidirectional scanning period (one-way period from bottom to top or top to bottom) elapses, the signal DEN To negative “L”.
The data addition circuits 21a and 21b are initialized when the signal DEN becomes “L”, and the values of the data signals TTDa and TTDb are made zero.

Each time the signal DEN changes from “H” to “L” in one frame period, the data processing circuit 11 fetches the immediately preceding data TTDa and TTDb, compares the difference | TTDa−TTDb |, and compares the minimum value | TTDa. -TTDb | min is obtained. If this is out of the permissible range, a correction signal TC is output to correct it and the delay circuit 2 is controlled, so that scanning in the x direction and y direction in the MEMS scanner 4 has a desired phase relationship. Correct the phase relationship.
The larger the difference value (| TTDa−TTDb |), the more the phase of the amplitude is shifted.
If | TTDa−TTDb | min is within an allowable range, the value of the signal TC does not change.
FIG. 9 schematically shows an embodiment of the data addition circuits 21a and 21b in FIG. Although this figure shows the data adding circuit 21a, the same may be applied to 21b.
An adder circuit 23a adds the data output TDa from the timer circuit 10a and the output data TTDa of this circuit, and outputs the result as ATDa.
Reference numeral 24a denotes a latch circuit. When the signal DEN is “H”, when the signal TEN is “H”, the input data ATDa is fetched and output as data TTDa. When the signal TEN is “L”, the current value of TTDa is set. Hold. When the signal DEN becomes “L”, it is initialized and the output TTDa becomes zero.

10 to 12 are conceptual diagrams for easily explaining the effects of the present invention based on FIG.
Now, in a series of scans, focus on, for example, scans highlighted with thick lines. This may be from the top to the bottom or from the bottom to the top in the y direction. For example, it is assumed that scanning is from top to bottom.
First, when the phase relationship between the vibrations in the x direction and the y direction is appropriate, a uniform desired trajectory is obtained on the entire scanning surface as shown in FIG. 10, and thus the scanning trajectory when the light beam passes near the position P is obtained. Since the scanning trajectory when passing through the vicinity of the position Q is vertically symmetrical with respect to the boundary between the photodiodes 7a and 7b placed at the center (here, the amplitude center) of the scanning range in the y direction, ideally | TTDa−TTDb | = 0.
On the other hand, if the phase relationship between the vibrations in the x direction and the y direction is not appropriate, the scanning locus is not uniform as shown in FIGS.
The photodiodes 7a and 7b are arranged outside the image area, and are received by turning on a monitor laser. It may be lit only during monitoring.

In the case shown in FIG. 11, the light beam follows a locus close to the center of the light receiving surface of the photodiode 7a near the position P, and the light beam follows a locus far from the center of the light receiving surface of the photodiode 7b near the position Q. Therefore, the light reception time at the photodiode 7a becomes longer, and the light reception time at the photodiode 7b becomes shorter.
Conversely, in the case shown in FIG. 12, the light beam follows a locus far from the center of the light receiving surface of the photodiode 7a near the position P, and the light beam near the center of the light receiving surface of the photodiode 7b near the position Q. Therefore, the light receiving time at the photodiode 7a becomes shorter, and the light receiving time at the photodiode 7b becomes longer.
That is, it is possible to obtain a difference larger than the single light reception timing shown in the first embodiment. In the present embodiment, the light reception timing is described twice when the density of the scanning trajectory is not high. However, in the case of more realistic scanning with a higher density of the scanning trajectory, the integration effect due to more light reception timings. And a larger difference, that is, detection accuracy can be obtained.

4 MEMS scanner as first optical scanning means and second optical scanning means 7, 20 Photodiode as light receiving means 11 Data processing circuit as phase correcting means 16 Screen surface x First direction y Second direction Sx First frequency signal Sy Second frequency signal

JP 2005-526289 A Japanese Patent Laid-Open No. 11-288444 Japanese Patent No. 3518099 JP-A-8-304474

Claims (12)

First optical scanning means that oscillates to reciprocally scan the light beam at the first frequency in a first direction by applying a signal at a first frequency;
Second optical scanning means that vibrates to reciprocally scan the light beam at the second frequency in the second direction by applying a signal having a second frequency different from the first frequency. In a two-dimensional optical scanning device,
Light reception for receiving the light beams of the first and second optical scanning means, arranged so as to be adjacent to each other at least two outside the effective scanning region in at least one of the first or second scanning directions. Means,
A phase detection unit that acquires a light reception time in each of the light receiving units in the folding of the light beam and detects a phase shift of vibrations of the first and second light scanning units based on the light reception times; A two-dimensional optical scanning device. The two-dimensional optical scanning device according to claim 1,
The two-dimensional optical scanning device according to claim 1 , wherein the light receiving means is arranged in a scanning direction having a higher frequency in the first or second scanning direction . The two-dimensional optical scanning device according to claim 1 or 2 ,
A two-dimensional optical scanning apparatus comprising phase correction means for correcting a phase shift of vibrations of the first and second optical scanning means detected by the phase detection means within a predetermined range . The two-dimensional optical scanning device according to claim 3 ,
The phase correction means adjusts the phase relationship between the signal of the first frequency and the signal of the second frequency so that the phase shift of vibration of the first and second optical scanning means is within a predetermined range. two-dimensional optical scanning apparatus and controls. The two-dimensional optical scanning device according to claim 3 or 4 ,
When the light beam is received by only one light receiving unit , the phase correction unit performs a pre-stage correction so that the light beam is received by two or more light receiving units, and then the first phase detected by the phase detection unit. A two-dimensional optical scanning device which corrects a phase shift of vibrations of the first and second optical scanning means within a predetermined range . The two-dimensional optical scanning device according to claim 1 ,
2. The two-dimensional optical scanning device according to claim 1, wherein the light receiving means is arranged in a scanning direction having a lower frequency in the first or second scanning direction . The two-dimensional optical scanning device according to claim 6 ,
The light receiving means is divided into a first group and a second group along the scanning direction with the low frequency, and the phase detection means has a light receiving time 1 of the light beam in the entire first group, and The light receiving time 2 of the light beam in the entire second group is acquired, and a phase shift of vibrations of the first and second optical scanning means is detected based on the comparison result 2 Dimensional optical scanning device. The two-dimensional optical scanning device according to claim 7,
The light reception time 1 or 2 is a total of one light reception time of the light beam detected by the whole light receiving means of the first group and the light beam detected by the whole light reception means of the second group, respectively. The phase detection means has a total of 1 and 2 of the light reception times for each part or all of the period of scanning in one direction in the scanning direction with the low frequency. The two-dimensional optical scanning device is characterized in that the phase difference of the vibrations of the first and second optical scanning means is detected based on the result . The two-dimensional optical scanning device according to claim 8,
Phase correction means for correcting the phase shift of vibration of the first and second optical scanning means detected by the phase detection means within a predetermined range;
The phase correction unit may be configured such that at least one of the difference values of the total 1 and 2 of the light receiving times acquired in one frame period in which the phase relationship between the first scan and the second scan makes a round is within a predetermined range. The two-dimensional optical scanning device is characterized by correcting a phase shift of vibrations of the first and second optical scanning means so as to enter . The two-dimensional optical scanning device according to any one of claims 6 to 9 ,
The light receiving means is divided into the first and second groups with the center of the scanning range in the scanning direction having a low frequency as a boundary, and is arranged so as to be symmetrical with each other. apparatus. In the two-dimensional optical scanning device according to any one of claims 1 to 10,
A two-dimensional optical scanning device , wherein the light receiving means is provided in an apparatus housing having the first and second optical scanning means . 12. The two-dimensional optical scanning device according to claim 1, wherein an image signal is input and the light beam is converted into the image signal 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 thereon .

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