JP2005250078A - Optical deflector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compact optical deflector which performs a two-dimensional deflection scanning with a single element. <P>SOLUTION: The optical deflector performs a deflection scanning with light emitted from a light source, and is composed of a supporting body, a vibration system, and a driving means which drives the vibration system. A driving having a deflection and scanning region of a substantially constant angular velocity is realized while a proper vibration mode. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an optical deflector that deflects light, and further to an image forming apparatus using the same. For example, it is suitable for an image forming apparatus such as a projection display that projects an image by two-dimensional deflection scanning of light.

  As an optical deflector, a polygon mirror that changes a reflection direction of incident light by rotating a polygonal column whose side surface is a reflection surface, and a galvano mirror that causes a plane mirror to vibrate about its axis by an electromagnetic actuator are well known. When scanning light two-dimensionally, a combination of these polygon mirrors and galvanometer mirrors, or a combination of two polygon mirrors is used. However, since a plurality of optical deflectors are required, not only the apparatus becomes large, It was necessary to arrange so that the scanning directions of the mirrors were orthogonal to each other, and optical adjustment was very complicated.

  In order to improve such a problem, the gimbal-type optical deflectors disclosed in Patent Document 1, Patent Document 2, and Patent Document 3 that can deflect and scan light two-dimensionally with a single optical deflector are disclosed.

  FIG. 9 is a schematic diagram illustrating a typical example of a gimbal type optical deflector represented by Patent Document 1, Patent Document 2, and Patent Document 3. The outer movable element 1023 is connected to the support body 1025 and the first torsion shaft 1017 by a first torsion spring 1024 so as to allow torsional vibration. On the other hand, the movable element 1021 is connected to the outer movable element 1023 and the second torsion shaft 1018 by a second torsion spring 1022 so as to allow torsional vibration. The movable element 1021 is provided with an optical deflector (not shown) for deflecting light such as a reflecting surface. Therefore, the outer movable element 1023 and the movable element 1021 can perform two-dimensional deflection scanning of light from the light source by torsionally oscillating around the first torsion axis 1017 and the second torsion axis 1018 by the driving means 1016, respectively. it can. Here, the driving means 1016 can be realized by, for example, permanent magnets provided on the movable element 1021 and the outer movable element 1023 and fixed coils for driving the permanent magnets. In particular, it is preferable to drive the optical deflector with a natural vibration mode frequency around the torsion axis determined by the shape and material of the optical deflector because a large displacement can be obtained with a small amount of energy.

  Assuming that the directions in which light is deflected and scanned by the torsional vibrations around the second torsion axis 1018 and the first torsion axis 1017 are the main scanning direction and the sub-scanning direction, respectively, as shown in FIG. In general, two-dimensional scanning (hereinafter, referred to as raster scanning in this specification) is performed in which the frequency of deflection scanning in the main scanning direction is much larger than that in the sub-scanning direction. Also, a method of scanning the surface to be scanned with a locus of a Lissajous figure as shown in FIG. 10A by setting the frequency ratio of deflection scanning in the main scanning direction and the sub-scanning direction very close to each other and fixing them. (In particular, the figure shows the case where the frequency ratio is 5: 6 and the phase difference is 90 ° in the main scanning direction). Also, as shown in FIGS. 10B and 10C, the frequency ratio of the deflection scanning in the main scanning direction and the sub-scanning direction is fixed to an arbitrary value, and the respective amplitude ratios are also fixed while the respective amplitude ratios are fixed. As shown in FIGS. 10 (b) and 10 (c), there is an example of performing two-dimensional scanning on the surface to be scanned in the α direction along the scanning curve and in the β direction which is substantially normal as shown in FIGS. .

Since such a gimbal type optical deflector performs two-dimensional deflection scanning with a single optical deflector, there is a possibility of realizing a small-sized two-dimensional scanning system with simple optical adjustment. Has the problem to show.
US Pat. No. 6,044,705 JP-A-7-27989 JP 2003-295102 A

  In the above conventional example, when the optical deflector is driven at a driving frequency substantially coincident with the frequency of the natural vibration mode and raster scanning is attempted, the angular velocity of the deflection scanning is caused by sinusoidal vibration in both the main scanning direction and the sub-scanning direction. Does not become constant and changes in a cosine manner. Since the angular speed of deflection scanning decreases toward both ends of the deflection scanning, the light scanning speed is high in the central portion of the scanned region, and the time for irradiating the scanned region is shorter than both ends.

  In particular, when the angular velocity in the sub-scanning direction changes, the line spacing of the main scanning lines due to deflection scanning in the main scanning direction is not constant, and the spacing is large at the center of the scanned region, and the spacing increases toward both ends in the sub-scanning direction. It gets smaller. Therefore, when an optical deflector is used in an image forming apparatus, image distortion and luminance unevenness are caused.

  On the other hand, the main scanning direction and the sub-scanning direction are driven at a driving frequency that substantially matches the frequency of the natural vibration mode, and the raster scan is not used, and the locus of the Lissajous figure as shown in FIGS. 10 (a), (b), and (c) Even in the case of two-dimensional scanning, the angular velocity of light deflected and scanned is not constant along the trajectory and is particularly fast at the center of the scanned region. In addition, two-dimensional scanning is performed in which the line spacing of the scanning lines is not constant within the scanned region. Accordingly, when used in an image forming apparatus, light cannot be effectively used for image formation at the center of the scanned region, and image distortion and luminance unevenness are caused.

  Furthermore, in the case of FIGS. 10B and 10C, since the deflection scanning path is different from a square, when the optical deflector is used in the image forming apparatus, it is necessary to perform deflection scanning larger than the area actually used for image formation. There is. For this reason, the utilization efficiency of deflection scanning is poor, and the apparatus becomes larger and consumes more power.

  In addition, when the frequency of deflection scanning in the sub-scanning direction is not set to the frequency of the natural vibration mode and the driving waveform is not sinusoidal vibration but is a vibration such as a triangular wave having a constant angular velocity region, it is driven to a desired vibration amplitude. A large generating force is required, and the driving means is increased in size and power consumption.

  The present invention has been made in view of the problems of the above-described conventional optical deflector, and realizes driving having a deflection scanning region having a substantially constant angular velocity while using a natural vibration mode for deflection scanning in the sub-scanning direction. Accordingly, it is an object to provide a small optical deflector capable of performing two-dimensional deflection scanning with a single element.

  An object of the present invention is an optical deflector that deflects and scans light from a light source, and the optical deflector includes a support, a vibration system, and a driving unit that drives the vibration system. Two or more first-axis swinging movable elements elastically connected in series by a plurality of first-axis torsion springs around a first torsion axis, and a second orthogonal to the first torsion axis A second axis swing movable element elastically coupled by a second axis torsion spring around the torsion axis; and an optical deflector disposed on the second axis swing movable element, and at least one of the first The single axis swing movable element is elastically connected to the support body by the first axial torsion spring around the first torsion axis, and the second axis swing movable element is the second torsion shaft. Around the second shaft torsion spring, it is elastically connected to at least one of the first shaft swinging movers, and the vibration system is And having at least two natural vibration modes having different frequencies around the first torsion axis, and the driving means simultaneously torsionally vibrates the vibration system in the at least two natural vibration modes around the first torsion axis. Is achieved by an optical deflector characterized by:

  The optical deflector according to the present invention realizes a drive having a deflection scanning region having a substantially equal angular velocity while using a natural vibration mode for deflection scanning in the sub-scanning direction, thereby performing two-dimensional deflection scanning with a single element. A small optical deflector that can be provided can be provided.

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

  FIG. 1 is a top view showing a first embodiment of an optical deflector according to the present invention. As shown in FIG. 1, the optical deflector of the present embodiment includes a first first axis swinging movable element 104, a first torsion shaft 104, and a second torsion axis 109 around two torsion axes. The three movable parts of the first shaft swing movable element 105 and the second shaft swing movable element 107 are elastically supported so as to be capable of torsional vibration.

  The support body 101 which is a mechanical ground plane and the first first-axis swinging movable element 104 are capable of torsional vibration about the first torsion shaft 108 by two first first-axis torsion springs 102. It is connected to. The second first axis swinging movable element 105 is located inside the first first axis swinging movable element 104 as shown in the figure, and the first first axis swinging movable element 104 and Two second first-axis torsion springs 103 are connected to be freely torsionally vibrated around the first torsion shaft 108. That is, the first first axis swing movable element 104 and the second first axis swing movable element 105 are mechanically elastically supported in series around the first torsion shaft 108.

  On the other hand, as shown in the figure, the second axis swing movable element 107 is positioned inside the second first axis swing movable element 105, and the second first axis swing movable element and the two first axis swing movable elements A biaxial torsion spring 106 is connected to the second torsion shaft 109 so as to be capable of torsional vibration. Further, the surface of the second axis swing movable element 107 has a reflection surface (not shown) as an optical deflector, and can reflect incident light and deflect it. In this embodiment, the reflecting surface is used as the light deflector. However, the light deflector may be composed of another light deflector such as a diffraction grating.

  Further, since the first torsion shaft 108 and the second torsion shaft 109 are substantially orthogonal to each other, the second shaft swinging movable element 107 has a first displacement along with the torsional displacement around the second torsion shaft 109. Displacement about two axes of the first torsion shaft 108 and the second torsion shaft 109 by the displacement of the first axis swing movable element 104 and the second first axis swing movable element 105 about the first torsion shaft 108. can do. Therefore, the light incident on the reflection surface of the second axis swing movable element 107 is deflected and scanned two-dimensionally by the torsional vibration around the two axes of the second axis swing movable element 107. Hereinafter, deflection scanning around the first torsion shaft 108 and the second torsion shaft 109 will be referred to as sub-scanning and main scanning, respectively. As shown in FIG. 11, the optical deflector according to the embodiment of the present invention performs two-dimensional scanning of light in a raster scan form, in which the speed of deflection scanning in the main scanning direction is much faster than that in the sub-scanning direction. . The detailed driving principle will be described below.

  FIG. 2A is a top view showing the electrode substrate 111 having the electrodes 110a, 110b, 110c, and 110d. The electrode substrate 111 is disposed to face the first first axis swing movable element 104, the second first axis swing movable element 105, and the second axis swing movable element 107 across the gap. FIG. 2A shows the positions of the electrode substrate 111, the first first-axis swinging movable element 104, the second first-axis swinging movable element 105, and the second-axis swinging movable element 107 as viewed from above. In order to show the relationship, in particular, the positions of the first torsion shaft 108 and the second torsion shaft 109 are shown. As illustrated, the electrodes 110a and 110b are installed on both sides of the second torsion shaft 109, and the electrodes 110c and 110d are installed on both sides of the first torsion shaft 108. In addition, a voltage can be independently applied to the four electrodes 110a, 110b, 110c, and 110d. FIG. 2B is a cross-sectional view showing a cross section of the optical deflector of the present embodiment at the first torsion shaft 108. The figure particularly shows the vicinity of the second axis swing movable element 107 in an enlarged manner. As described above, the electrodes 110a and 110b are arranged across the gap between the second axis swing movable element 107 and the gap. The second axis swing movable element 107 is electrically grounded, and a voltage is applied to the electrode 110b. When a voltage is applied to the electrode 110b, an electrostatic attractive force is generated, and a torque around the second torsion shaft 109 is applied to the second shaft swinging movable element 107. Therefore, the second axis swing movable element 107 can be displaced around the second torsion axis 109. Further, if a voltage is applied to the electrode 110a, torque in the reverse direction can be generated. Therefore, by alternately applying a voltage to the electrodes 110a and 110b, the second axis swinging movable element 107 is moved to the second torsion shaft 109. Can twist and vibrate around. Based on the same principle, the first first axis swing movable element 104 can be torsionally vibrated around the first torsion shaft 108 by the electrodes 110c and 110d. Therefore, the second first-axis swinging movable element 105 connected by the second first-axis torsion spring 103 can also torsionally vibrate around the first torsion shaft 108.

The optical deflector of the present embodiment has a natural vibration mode having a frequency s ₀ as the main scanning frequency for torsional vibration centered on the second torsion shaft 109. In particular, in this embodiment, the frequency s ₀ is 22 kHz. The second axis swing movable element 107 is driven around the second torsion shaft 109 at approximately this frequency by the electrodes 110a and 110b.

On the other hand, the torsional oscillation about the first torsion axis 108, the second-order natural oscillation mode of a frequency twice 2f ₀ of the first-order natural oscillation mode and the sub-scanning frequency of the frequency f ₀ of the sub-scanning frequency Can be treated as a two-degree-of-freedom vibration system having The first torsion axis 108 displacement of the drive means in which the electrode 111c to around, 111d is present in two frequency twice the frequency 2f ₀ contrast with the frequency _{f 0} of the first-order natural oscillation mode The example light deflector is driven about the first torsion axis 108. In the present embodiment, the frequency f ₀ is 60 Hz.

FIG. 3 is a diagram for explaining the displacement angle of torsional vibration of the frequency f ₀ of the second first-axis swinging movable element 105 with the horizontal axis as time t. Figure shows a portion corresponding to one cycle _{T 0} of the torsional vibration of the second first JikuYurado movable element _{105 (-T 0/2 <X} <T 0/2).

A curve 61 indicates a component of the sub-scanning frequency f _{0 in} the drive signals for driving the electrodes 110c and 110d, and reciprocates in the range of the maximum amplitude ± Φ ₁ as time t and angular frequency w ₀ = 2πf _0. ,

であらわされる正弦振動である。

This is a sinusoidal vibration.

On the other hand, the curve 62 shows a frequency component that is twice the sub-scanning frequency f ₀ , and oscillates within the maximum amplitude ± Φ ₂ range.

なる正弦振動である。

This is a sine vibration.

A curve 63 indicates the displacement angle of the torsional vibration of the second first-axis swinging movable element 105 resulting from such driving. Optical deflector of the present embodiment, the torsional vibration around the first torsion axis 108, as described above, 2 can be treated as the degree of freedom vibration system, natural vibration mode and frequency 2f ₀ of the sub-scanning frequency f ₀ Of the first torsional vibration about the first torsion shaft 108. Therefore, in the optical deflector according to the present embodiment, resonances excited by the driving signal of θ ₁ θ ₂ are generated around the first torsion axis 108. That is, the displacement angle of the second mover 105 of the curve 63 is a vibration of superposition of two sine vibrations,

It becomes a sawtooth vibration represented by Here, the curve 63 in FIG. 3 is a curve particularly when Φ ₁ is 1.20 and Φ ₂ is −0.25. FIG. 4 shows curves 61a and 63a and a straight line 64a obtained by differentiating the curves 61 and 63 and the straight line 64 of FIG. 3, and the angular velocities of these curves are explained. Compared with the curve 61a which depicts the angular speed of sinusoidal oscillation of frequency f _0, the curve 63a that indicates the angular velocity of the reciprocating vibration of the sawtooth second first JikuYurado movable element 105, in the section N-N ', the maximum point The angular velocity is within a range in which the angular velocity V ₁ and the angular velocity V ₂ at the minimum point are maximized and minimized. Therefore, in the application using the deflection scanning of light by the optical deflector of the present embodiment, if V ₁ and V ₂ exist within the allowable error of the angular velocity from the straight line 64a that is the equiangular velocity scanning, the section NN 'Can be regarded as a substantial equiangular scan. As described above, the angular velocity of the sub-scanning can be set wider by a sawtooth reciprocating vibration than in the case where the displacement angle is a sine wave. Therefore, by driving in the natural vibration mode in both the main scanning and the sub-scanning, a large displacement can be realized even if the generated force of the driving means is small, and even if raster scanning is performed, the main scanning in the section NN ′ is achieved. The scanning lines formed by the directional deflection scanning can be set at substantially equal intervals. Therefore, according to this embodiment, it is possible to realize a small optical deflector capable of performing good two-dimensional deflection scanning with a single element. In particular, the present embodiment, which is a sawtooth reciprocating vibration, is an embodiment suitable for an application using one of the forward scans (or return passes) of the deflection scan. Further, in this embodiment, the first first axis swing movable element 104, the second first axis swing movable element 105, and the second axis swing movable element 107 are connected by two torsion springs. Therefore, each torsion shaft has high rigidity against the force of the rotational / translational component other than the torsional direction elastically supported. For this reason, the natural vibration mode of torsional vibration in the deflection scanning direction can be easily separated from other natural vibration modes, and an optical deflector that is resistant to external impact can be obtained.

  FIG. 5 is a top view showing a second embodiment of the optical deflector of the present invention. In this embodiment, parts having the same functions as those in the first embodiment are denoted by the same reference numerals. As shown in FIG. 5, the optical deflector of the present embodiment includes a first first axis swing movable element 203, a first torsion axis 108, and a second torsion axis 109 around two torsion axes. The four movable parts of the second first-axis swinging movable element 205, the third first-axis swinging movable element 207, and the second-axis swinging movable element 209 are elastically supported so as to be capable of torsional vibration. Yes.

  The support body 201 which is a mechanical ground plane and the first first-axis swing movable element 203 are connected to be freely torsionally vibrated around the first torsion shaft 108 by the first first-axis torsion spring 202. Has been. Further, as shown in the drawing, the second first-axis swinging movable element 205 and the third first-axis swinging movable element 207 are also a second first-axis torsion spring 204 and a third first-axis torsion spring, respectively. By 206, the first torsion shaft 108 is coupled to be freely torsionally vibrated. That is, the first first axis swinging movable element 203, the second first axis swinging movable element 205, and the third first axis swinging movable element 207 are mechanically connected in series around the first torsion shaft 108. Is supported elastically.

  On the other hand, the second axis swing movable element 209 is located inside the third first axis swing movable element 207 as shown in the figure, and the third first axis swing movable element and the second axis are arranged. A torsion spring 208 is connected to the second torsion shaft 109 so as to be capable of torsional vibration. The surface of the second axis swing movable element 209 has a reflecting surface (not shown), and can reflect and deflect incident light.

  Further, since the first torsion shaft 108 and the second torsion shaft 109 are substantially orthogonal to each other, the second shaft swinging movable element 209 has a first displacement along with the torsional displacement around the second torsion shaft 109. The first torsion shaft 108 is obtained by torsional displacement around the first torsion shaft 108 of the first axis swing movable element 203, the second first axis swing movable element 205, and the third first axis swing movable element 207. The second torsion shaft 109 can be displaced around two axes. Therefore, the light incident on the reflecting surface of the second axis swing movable element 209 is deflected and scanned two-dimensionally by the torsional vibration around the two axes of the second axis swing movable element 209. As in the first embodiment, the optical deflector according to the embodiment of the present invention, as shown in FIG. 11, has a raster scanning pattern in which the deflection scanning speed in the main scanning direction is much faster than the deflection scanning in the sub scanning direction. Two-dimensional scanning of light is performed.

  The driving means can be driven by electrostatic attraction in the same manner as in the first embodiment.

The optical deflector of the present embodiment has a natural vibration mode having a frequency s ₀ as the main scanning frequency for torsional vibration centered on the second torsion shaft 109. In particular, in this embodiment, the frequency s ₀ is 22 kHz, and is driven around the second torsion shaft 109 at this frequency.

On the other hand, the torsional oscillation about the first torsion axis 108, the first-order natural oscillation mode and the sub-scanning frequency tripled frequency become secondary natural vibration mode of the frequency f ₀ of the sub-scanning frequency, Furthermore, it can be handled as a three-degree-of-freedom vibration system having a third-order natural vibration mode having a frequency five times the sub-scanning frequency. Displacement of the drive means to the surrounding first torsion axis 108 (not shown) is three times the frequency 3f and the frequency f ₀ contrast of the first-order natural oscillation mode _{0, 5} times the third frequency 5f ₀ The optical deflector of this embodiment is driven around the first torsion axis 108 at two frequencies. In the present embodiment, the frequency f ₀ is 60 Hz.

5, as the horizontal axis represents time t, is a diagram for explaining a displacement angle of the torsional vibration frequency f ₀ of the third first JikuYurado armature 207. Figure shows a portion corresponding to one cycle _{T 0} of the torsional vibration of the third first JikuYurado movable element _{207 (-T 0/2 <X} <T 0/2).

A curve 211 indicates a component of the sub-scanning frequency f _{0 in} the displacement of the third first-axis swing movable element 207. The curve 211 reciprocates in the range of the maximum amplitude ± Φ ₁ , and the time t, the angular frequency w. _{As 0} = 2πf ₀ ,

This is a sinusoidal vibration. The drive signal for driving the optical deflector of the present embodiment has a drive signal for driving the optical deflector of the first embodiment having two frequency components corresponding to two natural vibration modes. In the same manner as above, it has components of frequencies f ₀ , 3f ₀ , and 5f ₀ corresponding to the three natural vibration modes.

A curve 210 indicates a displacement angle of torsional vibration of the third first-axis swing movable element 207 resulting from such driving. Optical deflector of the present embodiment, the torsional vibration around the first torsion axis 108, as described above, 3 can be treated as the degree of freedom vibration system, 3f is natural oscillation mode and the frequency of the sub-scanning frequency f _{0 0} 5f ₀ second-order and third-order natural vibration modes are provided for torsional vibration about the first torsion shaft 108. Therefore, in the optical deflector of the present embodiment, resonances excited by the drive signals having the three different frequency components are generated around the first torsion axis 108. That is, the displacement angle of the third mover 207 of the curve 210 is a vibration of superposition of three sine vibrations,

This is a triangular wave-like vibration. Here, the curve 210 in FIG. 5 is a curve particularly when Φ ₁ is 1, Φ ₂ is −0.08, and Φ ₃ is 0.01. FIG. 6 shows curves 210a and 211a obtained by differentiating the curves 210 and 211 in FIG. 5, and the angular velocities of these curves are explained. Compared with the curve 211a depicts the angular speed of sinusoidal oscillation of frequency _{f 0,} the curve 210a indicating the angular velocity of the triangular reciprocal vibration of the third first JikuYurado armature 207, section M-M ', section L-L In “(L−L ′), the angular velocity V _{1 at the} maximum point and the angular velocity V _{2 at the} minimum point in the section from L in FIG. 6 to the phase corresponding to L ′ appearing on the right side of the time axis ( In the section LL ′, the angular velocities are within a range in which the angular velocity -V _{2 at} the local maximum point and the angular velocity at the minimum point -V ₁ ) are maximized and minimized. Therefore, in the application using the deflection scanning of the light by the optical deflector of the present embodiment, as in the first embodiment, if V ₁ and V ₂ exist within the tolerance of the angular velocity, the section MM ', Section LL' can be regarded as a substantially equiangular scan. As described above, the triangular wave-like reciprocating vibration can set the sub-scanning angular velocity in a wider area where the angular velocity is substantially equal to that when the displacement angle is a sine wave. Therefore, by driving in the natural vibration mode in both the main scanning and the sub scanning, a large displacement can be realized even if the generated force of the driving means is small, and even if raster scanning is performed, the section MM ′ and the section L- The scanning lines formed by the deflection scanning in the main scanning direction within L ′ can be set at substantially equal intervals. Therefore, according to this embodiment, it is possible to realize a small optical deflector capable of performing good two-dimensional deflection scanning with a single element. In particular, unlike the first embodiment, this embodiment, which is a triangular wave-like reciprocating vibration, is an embodiment suitable for applications using both forward and backward scanning of deflection scanning.

  FIG. 7 is a diagram showing an embodiment of an optical apparatus using the optical deflector. Here, an image display device is shown as an optical apparatus. In FIG. 7, reference numeral 2001 denotes an optical deflector according to the present invention, which deflects and scans incident light on a projection surface 2005 in a raster scan manner. Reference numeral 2002 denotes a laser light source. Reference numeral 2003 denotes a lens or lens group, reference numeral 2004 denotes a writing lens or lens group, and reference numeral 2005 denotes a projection surface. The laser light incident from the laser light source 2002 is subjected to predetermined intensity modulation related to the optical scanning timing, and is scanned two-dimensionally by the optical deflector 2001. The scanned laser light forms an image on the projection surface 2005 by the writing lens 2004.

  By using the optical deflector according to the present invention, light can be deflected and scanned in a raster scan manner at a substantially equal angular velocity while being a small optical deflector that uses power-saving resonance. For this reason, the line interval of the main scanning lines (here, the horizontal lines of the projection plane 2005) of the image to be drawn can be made substantially constant, uneven brightness of the image can be eliminated, and the entire vertical size of the image can be made constant. It becomes possible to.

It is a top view which shows the optical deflector of 1st Example of this invention. (A) It is a top view which shows the electrode substrate of the 1st Example of this invention. (B) It is sectional drawing which shows the principle of operation of the 1st Example of this invention. It is a figure which shows the displacement angle of the light deflected and scanned by the optical deflector of the 1st Example of this invention. It is a figure which shows the angular velocity of the light deflected and scanned by the optical deflector of the 1st Example of this invention. It is a top view which shows the optical deflector of the 2nd Example of this invention. It is a figure which shows the displacement angle of the light deflected and scanned by the optical deflector of the 2nd Example of this invention. It is a figure which shows the angular velocity of the light deflected and scanned by the optical deflector of the 2nd Example of this invention. It is a figure which shows one Embodiment of the optical instrument using the optical deflector of this invention. It is a top view which shows the optical deflector of a prior art example. It is a conceptual diagram which shows the locus | trajectory of the deflection | deviation scanning of the light of the optical deflector of a prior art example. It is a conceptual diagram which shows the locus | trajectory of the deflection | deviation scanning of the light of a raster scan.

Explanation of symbols

61, 61a Curve 62 Curve 63, 63a Curve 64, 64a Line 71, 71a Curve 72, 72a Curve 101 Support body 102 First first axis torsion spring 103 Second first axis torsion spring 104 First first axis Oscillating mover 105 Second first axis oscillating mover 106 Second axis torsion spring 107 Second axis oscillating mover 108 First torsion axis 109 Second torsion axis 110a, 110b, 110c, 110d Electrode 111 Electrode substrate 201 Support 202 First first axis torsion spring 203 First first axis swinging movable element 204 Second first axis torsion spring 205 Second first axis swinging movable element 206 Third third One-axis torsion spring 207 Third first-axis swing movable element 208 Second-axis torsion spring 209 Second-axis swing movable element 210, 210a Curve 211, 211a Curve 1016 Drive Stage 1018 the second torsion axis 1017 first torsion axis 1021 mover 1022 second torsion springs 1023 outside the movable element 1024 first torsion spring 1025 supports 2001 optical deflector 2002 laser light source 2003 lens 2004 writing lens 2005 projection surface

Claims (5)

An optical deflector that deflects and scans light from a light source,
The optical deflector is
A support and a vibration system;
And driving means for driving the vibration system,
The vibration system is
Two or more first-axis swing movable elements elastically connected in series with a plurality of first-axis torsion springs around a first torsion axis;
A second axis swinging movable element elastically connected by a second axis torsion spring around a second torsion axis perpendicular to the first torsion axis;
An optical deflector installed on the second axis swing movable element,
At least one of the first axis swing movable elements is:
The first torsion spring is elastically connected to the support body around the first torsion axis,
The second axis swing movable element is
Around the second torsion shaft, the second shaft torsion spring is elastically connected to at least one of the first shaft swinging movable elements,
The vibration system is
Around the first torsion axis;
Having at least two natural vibration modes of different frequencies;
The drive means moves the vibration system,
At least two of the natural vibration modes about the first torsion axis;
An optical deflector characterized by causing torsional vibration at the same time. The vibration system includes two first axis swing movable elements and four first axis torsion springs,
The first axis swing movable element is connected to each other by two first axis torsion springs,
One of the first axis swing movable elements is connected to the support body by two first axis torsion springs,
2. The optical deflector according to claim 1, wherein the other first axis swing movable element is connected to the second axis swing movable element by two second axis torsion springs.   The vibration system has two natural vibration modes having different frequencies around the first torsion axis, and one frequency of the natural vibration mode is twice the other frequency. Item 4. The optical deflector according to Item 1.   The vibration system has two natural vibration modes having different frequencies around the first torsion axis, and one frequency of the natural vibration mode is three times the other frequency. Item 4. The optical deflector according to Item 1.   A light source and the optical deflector according to claim 1, wherein the optical deflector is controlled by the optical deflector control device, and the light from the light source is converted into the optical deflector. An image display device characterized by projecting at least a part of the light onto an image display body.

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