JP5381751B2 - Optical scanner and image display apparatus using optical scanner - Google Patents

Description

  The present invention relates to an optical scanner used in a laser printer, a projection display device, and the like, and an image display device using the optical scanner.

  Conventionally, optical scanners are used in laser printers, projection display devices, and the like. Among optical scanners, an optical scanner using a MEMS (Micro-Electro-Mechanical Systems) mirror includes a mirror unit, a beam that supports the mirror unit, transmits a driving force to the mirror unit, and is coupled to the beam. In recent years, it has been attracting attention as a lightweight and compact optical scanner.

  FIG. 22 is a perspective view of the optical scanner 101 using the MEMS mirror disclosed in Patent Document 1. In FIG. The optical scanner 101 includes a vibrating body 102 and a base 103. The vibrating body 102 includes a mirror unit 104, beams 105A and 105B, drive units 106A, 106B, 106C, and 106D, and an outer frame 107. The base 103 includes a support frame 109 and a recess 110.

  Each of the beams 105A and 105B includes support beams 105C and 105D connected to the mirror unit 104. The beam 105A and the beam 105B are opposed to each other with the mirror portion 104 interposed therebetween. The beams 105A and 105B are connected to the outer frame 107. The drive units 106A and 106C are provided across the beam 105A and the outer frame 107. The drive units 106B and 106D are provided across the beam 105B and the outer frame 107. The outer frame 107 surrounds the outer periphery of the mirror unit 104 and the beams 105A and 105B. The outer frame 107 is provided on the support frame 109 of the base 103.

  The drive units 106A, 106B, 106C, and 106D are configured by a piezoelectric body and two electrodes that sandwich the piezoelectric body. The piezoelectric bodies of the drive units 106A, 106B, 106C, and 106D are polarized by applying a voltage to the electrodes of the drive units 106A, 106B, 106C, and 106D. The polarized piezoelectric bodies of the drive units 106A, 106B, 106C, and 106D expand and contract in the longitudinal direction of the beams 105A and 105B. A voltage having periodicity is applied to the electrodes of the driving units 106A, 106B, 106C, and 106D, so that the beams 105A and 105B are torsionally vibrated around the axis AX. Due to the torsional vibration, the mirror unit 104 swings around the axis AX. When the mirror unit 104 swings, the reflecting surface 108 swings. The reflecting surface 108 reflects the incident light bundle while swinging. As described above, the optical scanner 101 scans the light beam incident on the reflecting surface 108.

  The support frame 109 is formed on the upper surface of the base 103. The recess 110 is formed in a region surrounded by the support frame 109. The outer frame 107 of the vibrating body 102 is fixed on the support frame 109 of the base 103 by adhesion, laser welding, clamp fixing, or the like. By fixing the outer frame 107 on the support frame 109, the vibrating body 102 is disposed on the base 103. The optical scanner 101 is configured as described above. Since the outer frame 107 is fixed on the support frame 109, unnecessary movement other than the swinging of the mirror unit 104 can be reduced. Therefore, the optical scanner 101 can be scanned with high accuracy.

JP 2003-57586 A

  However, since the optical scanner disclosed in Patent Document 1 is very small, the fixing position is likely to be displaced when the vibrating body and the base are fixed. When this fixed position shift occurs, the characteristics of the optical scanner are affected. For example, problems such as a rotation error occur as an effect on the characteristics of the optical scanner. The rotation error is a value determined by the distance ER between the extension line EL of the support beam BM and the swing axis AX of the mirror part MR as shown in FIG. As described above, there is a problem that the characteristics of the optical scanner vary due to the influence of the fixed position deviation on the characteristics of the optical scanner.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an optical scanner in which variations in characteristics of the optical scanner due to a fixed position shift are reduced. It is another object of the present invention to provide an image display apparatus using an optical scanner in which variations in characteristics of the optical scanner due to a fixed position shift are reduced.

  In order to achieve the above object, the present invention according to claim 1 is an optical scanner that reflects and scans an incident light beam, the mirror unit having a reflecting surface that reflects the incident light beam, and the mirror. A pair of support beams extending from both sides of the mirror unit on a plane parallel to the reflection surface, and connected to the pair of support beams and on the plane parallel to the reflection surface A movable member that extends in an extending direction away from the vibration member and transmits vibrations to the pair of support beams; and a drive unit that is provided on the vibration member and swings the mirror unit; A first connecting plate connected to the vibration member and extending in a direction parallel to the reflection surface and perpendicular to the extending direction of the vibration member; and the first connection plate on a surface parallel to the reflection surface. A pair of first and second plates connected to each other across the first connecting plate. A connecting plate, extending in a direction perpendicular to an extension line connecting the outer plate surrounding the movable part and the pair of support beams, and spaced apart from each other in a direction parallel to the extension line, and parallel to the reflecting surface And a pair of bases fixedly provided on one surface of the outer plate extending in the direction.

  According to a second aspect of the present invention, in the first aspect of the present invention, the vibrating member surrounds the mirror portion and the pair of support beams, is coupled to each of the pair of support beams, and is attached to the reflective surface. A pair of first plate portions extending in one direction side of the pair of support beams from a connecting portion with the pair of support beams on a parallel plane and in a direction perpendicular to the extension line; A second plate portion connected to both of the first plate portions and extending on a plane parallel to the reflection surface, and the pair of first plate portions and the second plate portion are connected to the reflection surface. On the other side of the pair of support beams in a direction perpendicular to the extension line, and the outer plate includes the second plate portion on one side and the second plate on the other side. A pair of the first connecting plates respectively connected to the second plate portion and extending in a direction parallel to the extension line; and the extension The pair of pairs that are spaced apart from the movable part in a direction parallel to the mirror part and are located on both sides of the mirror part, are connected to both of the pair of first connection plates, and extend in a direction perpendicular to the extension line. A second connecting plate, wherein the drive unit is a pair of drive units provided on the second plate part on the one-direction side and the second plate part on the other-direction side, respectively. It is what.

  According to a third aspect of the present invention, in the second aspect of the present invention, the distance between the pair of bases in the direction parallel to the extension line is the dimension of the second plate portion in the direction parallel to the extension line. It is above and below the dimension of the said 1st connection board, It is characterized by the above-mentioned.

  According to a fourth aspect of the present invention, in the third aspect of the present invention, the distance between the pair of bases in the direction parallel to the extension line is the dimension of the first connecting plate in the direction parallel to the extension line. The dimension of the pair of bases in the direction perpendicular to the extension line is equal to the dimension of the pair of second connecting plates in the direction perpendicular to the extension line.

  A fifth aspect of the present invention is an image display device, the optical scanner according to any one of the first to fourth aspects, a light source unit that supplies light to the optical scanner, and scanned by the optical scanner. And an optical system that guides the scanning light to the eyes of the user.

  When the inventor performs numerical analysis on the optical scanner, when the base is a pair of bases that are spaced apart from each other, variations in characteristics of the optical scanner such as a rotation error due to a fixed misalignment are reduced. Confirmed that it will be. On the basis of confirmation of the analysis results, according to the optical scanners of claims 1 to 4, the pair of bases are positioned apart from each other on one surface side of the outer plate, It is fixed to the surface. Therefore, variations in the characteristics of the optical scanner due to the fixed position deviation are reduced. In addition, when the distance between the pair of bases is equal to or larger than the dimension of the second plate portion and equal to or smaller than the dimension of the first connecting plate, the variation in the characteristics of the optical scanner due to the fixed position deviation is significantly reduced. confirmed. Therefore, according to the optical scanners of the third and fourth aspects, the variation in the characteristics of the optical scanner due to the fixed positional deviation is reduced. Further, when the distance between the pair of bases is equal to the dimension of the first connecting plate and the dimension of the pair of bases is equal to the distance between the pair of first connecting plates, the characteristics of the optical scanner due to the most fixed positional deviation. It was confirmed that the variation of the was reduced. Therefore, according to the optical scanner of the fourth aspect, the variation in the characteristics of the optical scanner due to the fixed positional deviation is reduced to the maximum.

  According to the image display device of the fifth aspect, the optical scanner in which the variation in the characteristics of the optical scanner due to the fixed positional deviation is reduced is used. Therefore, since high-precision optical scanning can be performed, high-quality image display can be performed.

1 is a perspective view showing an appearance of an optical scanner 1 according to a first embodiment of the present invention. 2 is a top view of the optical scanner 1. FIG. 2 is a bottom view of the optical scanner 1. FIG. 2 is a diagram showing an electrical configuration of the optical scanner 1. FIG. It is explanatory drawing for demonstrating rocking | fluctuation of the mirror part 5 of the said optical scanner. It is a bottom view which shows the structure of the conventional optical scanner 1 used in the case of simulation. It is a bottom view which shows the structure of one Example of the optical scanner 1 which concerns on the 1st Embodiment of this invention used in the case of simulation. It is a bottom view which shows the structure of one Example of the optical scanner 1 which concerns on the 1st Embodiment of this invention used in the case of simulation. It is a bottom view which shows the structure of one Example of the optical scanner 1 which concerns on the 1st Embodiment of this invention used in the case of simulation. It is a bottom view which shows the structure of one Example of the optical scanner 1 which concerns on the 1st Embodiment of this invention used in the case of simulation. It is a bottom view which shows the structure of one Example of the optical scanner 1 which concerns on the 1st Embodiment of this invention used in the case of simulation. It is a figure which shows the rotation error of each optical scanner 1 shown in FIGS. It is a figure which shows the resonant frequency difference of each optical scanner 1 shown in FIGS. It is a figure which shows the largest stress difference of each optical scanner 1 shown in FIGS. It is explanatory drawing for demonstrating adhesion gap GP. It is a figure which shows the usage example in the retina scanning display 201 of the said optical scanner 1. FIG. It is a perspective view which shows the external appearance of the optical scanner 1 which concerns on the 2nd Embodiment of this invention. It is a bottom view which shows the structure of the conventional optical scanner 301 used in the case of simulation. It is a bottom view which shows the structure of the comparative example of the optical scanner 301 used in the case of simulation. It is a bottom view which shows the structure of one Example of the optical scanner 301 based on the 2nd Embodiment of this invention used in the case of simulation. It is a figure which shows the rotation error of each optical scanner 301 shown in FIGS. It is a perspective view which shows the conventional optical scanner 101. FIG. It is explanatory drawing for demonstrating rotation error ER. It is explanatory drawing for demonstrating rotation error ER.

(First embodiment)
A first embodiment of the present invention will be described with reference to the drawings.

[Optical scanner appearance]
Hereinafter, the appearance of the optical scanner 1 of the present embodiment will be described with reference to the drawings. FIG. 1 is a perspective view showing an appearance of the optical scanner 1 of the present embodiment. FIG. 2 is a top view of the optical scanner 1. As shown in FIGS. 1 and 2, the optical scanner 1 includes a movable portion 2, an outer plate 3, and a pair of bases 4. The movable part 2 in the present embodiment is an example of the movable part of the present invention. The outer plate 3 in the present embodiment is an example of the outer plate of the present invention. The base 4 in this embodiment is an example of the base of the present invention.

  The movable part 2 includes a mirror part 5, a pair of support beams 6, a vibration member 7, and drive parts 8A and 8B. The mirror unit 5 includes a reflective surface 51. The reflecting surface 51 reflects the incident light bundle. The mirror unit 5 in the present embodiment is an example of the mirror unit of the present invention. The reflective surface 51 in the present embodiment is an example of the reflective surface of the present invention.

  The pair of support beams 6 extend from both sides of the mirror unit 5 on a plane parallel to the reflection surface 51. Thereafter, the direction parallel to the extension line AX connecting the pair of support beams 6 shown in FIGS. 1 and 2 is the X-axis direction, the direction parallel to the reflecting surface 51 and the direction perpendicular to the extension line AX is the Y-axis. The direction perpendicular to the reflection surface 51 is defined as the Z-axis direction. Therefore, for example, a plane parallel to the reflecting surface 51 is an XY plane. However, “parallel” and “vertical” are not strictly parallel and vertical. That is, for example, hereinafter, “surface parallel to the reflective surface 51” indicates a plane substantially parallel to the reflective surface 51. Hereinafter, the same applies to “upper”, “lower” and the like. In the following, “upper” means the positive direction of the Z axis shown in FIGS. 1 and 2, and “lower” means the negative direction of the Z axis shown in FIG. And The definitions of the X-axis direction, the Y-axis direction, and the Z-axis direction are common to other drawings. The extension line AX deviates from the swing axis when a rotation error or the like occurs as shown in FIG. However, for the sake of simplicity, the extension line AX is hereinafter referred to as the same axis as the swing axis. The support beam 6 in the present embodiment is an example of the support beam of the present invention.

  The vibration member 7 is connected to the pair of support beams 6. The vibration member 7 extends in a direction away from the mirror unit 5 in the XY plane. The vibration member 7 surrounds the mirror unit 5 and the pair of support beams 6. The vibration member 7 transmits vibration to the pair of support beams 6. The vibration member 7 in the present embodiment is an example of the vibration member of the present invention.

  The vibration member 7 includes a pair of first plate portions 71 and a pair of second plate portions 72. As shown in FIG. 2, the first plate portion 71 extends from the connecting portion CP with the support beam 6 to the one-direction side OS of the support beam in the Y-axis direction. As shown in FIG. 2, the first plate portion 71 extends from the connecting portion CP with the support beam 6 to the other direction AS of the support beam in the Y-axis direction. Each of the pair of second plate portions 72 is connected to both of the pair of first plate portions 71. The second plate portion 72 extends in the XY plane. The 1st board part 71 in this embodiment is an example of the 1st board part of this invention. The 2nd board part 72 in this embodiment is an example of the 2nd board part of this invention.

  The drive units 8A and 8B are provided on the second plate portion 72 on the Y axis positive direction side and the second plate portion 72 on the Y axis negative direction side, respectively. The drive units 8A and 8B include a piezoelectric body, and an upper electrode and a lower electrode provided above and below the piezoelectric body so as to sandwich the piezoelectric body. The piezoelectric bodies of the drive units 8A and 8B are formed of lead zirconate titanate (hereinafter referred to as “PZT”) which is a piezoelectric material. The upper and lower electrodes of the drive units 8A and 8B are made of metal. The drive units 8A and 8B in the present embodiment are an example of the drive unit of the present invention.

  The outer plate 3 includes a pair of first connection plates 31 and a pair of second connection plates 32. The pair of first connection plates 31 are connected to the second plate portion 72 of the vibration member 7. The pair of first connecting plates 31 extends in the X-axis direction. The pair of first connecting plates 31 is located in a region RG indicated by a pair of two-dot chain lines and a two-dot chain line arrow in FIG. In the XY plane, the pair of second connection plates 32 intersects and is connected to both of the pair of first connection plates 31, and is vertically connected to both of the pair of first connection plates 31 in the present embodiment. The pair of second connection plates 32 are respectively positioned with the pair of first connection plates 31 interposed therebetween. The region RG is a region between the pair of second connecting plates 32 as shown in FIG. A through hole 33 penetrating in the Z-axis direction is located between the pair of second connecting plates 32 and the movable portion 2. Therefore, the pair of second connection plates 32 are positioned away from the movable portion 2 in the X direction. The pair of second connection plates 32 are respectively located on both sides of the mirror unit 5 in the X direction. The pair of second connecting plates 32 extends in the Y-axis direction. The outer plate 3 surrounds the movable part 2. The 1st connection board 31 in this embodiment is an example of the 1st connection board of this invention. The 2nd connection board 32 in this embodiment is an example of the 2nd connection board of the present invention.

  The base 4 will be described with reference to FIGS. 1 and 3. FIG. 3 is a bottom view of the optical scanner 1. The pair of bases 4 extends in the Y-axis direction. The pair of bases 4 are separated from each other in the X-axis direction. The pair of bases 4 are provided by being bonded to the lower surface of the outer plate 3. The base 4 in this embodiment is an example of the base of the present invention.

[Electrical configuration]
Hereinafter, the electrical configuration of the optical scanner 1 will be described with reference to FIG. The optical scanner 1 includes a control unit 9 shown in FIG. The control unit 9 includes a drive voltage generation unit 91 and a drive control unit 92. The drive voltage generation unit 91 generates an adjustable drive voltage. The drive voltage generation unit is connected to the upper electrode and the lower electrode of the drive units 8A and 8B. The drive control unit 92 is connected to the drive voltage generation unit 91. The drive control unit 92 controls the drive voltage generation unit 91. The drive control unit 92 causes the drive voltage generation unit 91 to generate a drive voltage. The drive voltage generated by the drive voltage generation unit 91 is applied between the upper electrode and the lower electrode of the drive units 8A and 8B. The drive units 8A and 8B are driven by the application of the drive voltage. The movable unit 2 is driven by driving the drive units 8A and 8B.

[Description of operation]
The operation of the optical scanner 1 will be described with reference to FIG. The drive voltage generation unit 91 supplies a drive voltage having an opposite phase between the upper electrode and the lower electrode of the drive unit 8A and between the upper electrode and the lower electrode of the drive unit 8B. The drive voltage changes periodically with time. When the piezoelectric body of the drive unit 8A contracts in the Y-axis direction due to this voltage application, the piezoelectric body of the drive unit 8B extends in the Y-axis direction. When the piezoelectric body of the drive unit 8A extends in the Y axis direction, the piezoelectric body of the drive unit 8B contracts in the Y axis direction.

  Due to the displacement of the piezoelectric body, the second plate portion 72 on the positive side of the Y axis and the second plate portion 72 on the negative direction side of the Y axis are bent in opposite directions of the Z axis. That is, as shown in FIG. 5, when the second plate portion 72 on the positive direction side of the Y axis is bent toward the positive direction side of the Z axis, the second plate portion 72 on the negative direction side of the Y axis is Bends in the negative direction of the Z axis. When the second plate portion 72 on the positive direction side of the Y axis is bent toward the negative direction side of the Z axis, the second plate portion 72 on the negative direction side of the Y axis is bent toward the positive direction side of the Z axis. . In this way, the second plate portion 72 is periodically bent, and a standing waveform deformation with the extended line AX as a node occurs in the vibration member 7. The deformation generated in the vibration member 7 induces torsional vibration about the extension line AX of the support beam 6. As a result, the mirror unit 5 swings around the extension line AX. As the mirror unit 5 swings, the reflecting surface 51 of the mirror unit 5 swings around the extension line AX. The light beam incident on the reflecting surface 51 is scanned by the swinging of the reflecting surface 51.

[Production method]
A method for manufacturing the optical scanner 1 according to this embodiment will be described. First, an elastic substrate is prepared as a material to be etched. Next, an etching process is performed on the material to be etched, and the movable portion 2 and the outer plate 3 are formed. When the movable part 2 and the outer plate 3 are formed, a resist film is formed in a region of the surface of the movable part 2 excluding a place where the lower electrode is provided. When the resist film is formed, a metal such as platinum (Pt) or gold (Au) is deposited on the movable portion 2 having the resist film formed on the surface. By this process, a metal lower electrode is laminated on the movable part 2. When the lower electrode is laminated, the resist film is removed from the surface of the movable part 2. Next, a piezoelectric body is provided on the lower electrode. In the process of installing the piezoelectric body, first, a resist film is formed in a region of the surfaces of the movable portion 2 and the lower electrode, excluding the place where the piezoelectric body is provided on the lower electrode. When the resist film is formed, an aerosol of PZT, which is a piezoelectric material, is sprayed onto the movable part 2 and the lower electrode having the resist film formed on the surface. By this process, a PZT piezoelectric film is formed on the lower electrode, and a piezoelectric body is formed. When the piezoelectric body is formed, the resist film is removed from the surfaces of the movable portion 2 and the lower electrode. When the process of installing the piezoelectric body is performed, the upper electrode is provided on the piezoelectric body. In the upper electrode lamination process, metal deposition similar to the above-described lower electrode lamination process is used. When the upper electrode is laminated on the piezoelectric body, a reflective surface 51 of a metal film such as aluminum (Al) or gold (Au) is formed in a region of the substrate where the mirror portion 5 is formed. The metal vapor deposition described above is used to form the reflective surface 51. When the reflecting surface 51 is formed, the movable part 2 and the pair of bases 4 are bonded together with an adhesive. For example, an epoxy adhesive is used as the adhesive. The optical scanner 1 is manufactured by the above manufacturing method.

[Analysis result]
An analysis result by simulation of various characteristic values depending on the separation interval SD of the optical scanners 1 and 401 will be described with reference to FIGS. FIG. 6 is a bottom view of a comparative optical scanner 401 having a structure different from that of the optical scanner 1 of the present embodiment. 7 to 11 are bottom views showing examples of the optical scanner 1 according to the present embodiment, respectively. 12 to 14, the numerical values of the maximum stress differences described corresponding to the models shown in FIGS. 6 to 11 are obtained when the optical deflection angle of the optical scanners 1 and 401 is set to 46 degrees. It is a numerical value. The numerical values of the rotation error and the resonance frequency difference are constant regardless of the set value of the optical deflection angle of the optical scanners 1 and 401. The separation interval SD is the separation interval under the first connecting plate 31 of the pair of bases 4 in the X-axis direction shown in FIGS. In the optical scanner 401 shown in FIG. 6, the separation interval SD = 0 μm. The optical scanner 401 shown in FIG. 6 is different from the optical scanner 1 of this embodiment shown in FIGS. 7 to 11 in that the separation distance SD is a zero value. The optical scanner 1 shown in FIGS. 10 and 11 has the same separation interval SD as shown in FIGS. 10 and 11. However, the dimension DA in the Y-axis direction of the pair of bases 4 shown in FIG. 10 is equal to the dimension DB of the pair of second connecting plates in the Y-axis direction. That is, the dimension DA of the pair of bases 4 shown in FIG. 10 is DB = DB. On the other hand, the dimension DA in the Y-axis direction of the pair of bases 4 shown in FIG. 11 is twice the dimension DC of the first connection plate in the Y-axis direction from the dimension DB of the pair of second connection plates in the Y-axis direction. Equal to the dimension minus the dimension. That is, the dimension DA of the pair of bases 4 shown in FIG. 11 is DB-2DB. Although not shown, the dimension DA in the Y-axis direction of the pair of bases 4 shown in FIGS. 6 to 9 is equal to the dimension DA in the Y-axis direction of the pair of bases 4 shown in FIG.

  The dimensions of each part of the optical scanner 1 set during the simulation will be described with reference to FIG. The dimension DB of the pair of second connecting plates in the Y-axis direction is dimension DB = 21.0 μm. The dimension DC of the first connecting plate in the Y-axis direction is dimension DC = 1.0 μm. The dimension DD of the outer plate 3 in the X-axis direction is dimension DD = 11.8 μm. The dimension DE of the second plate portion 72 in the X-axis direction is dimension DE = 6.4 μm. The dimension DF of the first connecting plate 31 in the X-axis direction is dimension DF = 9.8 μm. The above dimension DB, dimension DC, dimension DD, dimension DE, and dimension DF have the same dimensions in the optical scanners 1 and 401 shown in FIGS. The separation intervals SD of the optical scanners 1 and 401 shown in FIGS. 6 to 11 are SD = 0.0, 3.0, 6.4, 8.3, 9.8, and 9.8 μm, respectively. As described above, the separation interval SD of the optical scanner 1 shown in FIGS. 10 and 11 is the same value as the separation interval SD = 9.8 μm.

  FIG. 12 shows the analysis result of the rotation error generated in each of the optical scanners 1 and 401 shown in FIGS. 6 to 11 when the adhesion deviation GP in the Y-axis direction as shown in FIG. 15 occurs. In the present embodiment, the pair of bases 4 are provided by being bonded to the lower surface of the outer plate 3, and hence a fixed position shift is referred to as an adhesive shift. In the present embodiment, the rotation error includes displacement PA when the one end AE of the mirror MR shown in FIG. 24 is swung, and displacement ZB when the other end BE of the mirror MR is swung PB. In this case, (rotational error) = {(PA + PB) / PA} × 100. FIG. 24 is a side view of the mirror part MR shown in FIG. 23 when viewed from the Y-axis direction, that is, the swing axis AX direction. In FIG. 24, the mirror part MR indicated by a solid line indicates the mirror part MR at rest. In FIG. 24, a mirror portion MR indicated by a two-dot chain line indicates the mirror portion MR at a certain time during swinging. For example, when the displacement PA = 1 μm and the displacement PB = −0.5 μm, the rotation error is (rotation error) = {(1-0.5) / 1} × 100 = 50%. The analysis was performed with the adhesion deviation GP in the Y-axis direction set as adhesion deviation GP = 250 μm. As shown in FIG. 12, the rotation error of the optical scanner 1 according to this embodiment shown in FIGS. 7 to 11 is smaller than the rotation error of the conventional optical scanner 401 shown in FIG. Therefore, the optical scanner 1 according to the present embodiment has a small rotational error that occurs when an adhesion shift occurs in the Y-axis direction, that is, the direction perpendicular to the extension line AX. 12, the rotation error of the optical scanner 1 shown in FIGS. 7 and 8 is compared with the rotation error of the optical scanner 1 shown in FIGS. 9, 10, and 11. 10 and the rotation error of the optical scanner 1 shown in FIG. 11 is very small. Therefore, it is desirable that the separation distance SD between the pair of bases 4 in the X-axis direction is not less than the dimension DE of the second plate portion 72 in the X-axis direction and not more than the dimension DF of the first connecting plate 31 in the X-axis direction. . As shown in FIG. 12, the rotation error of the optical scanner 1 shown in FIG. 10 is the smallest among the optical scanners 1 shown in FIGS. Therefore, the spacing SD between the pair of bases 4 in the X-axis direction is equal to the dimension DF of the first connecting plate 31 in the X-axis direction, and the dimension DA of the pair of bases 4 in the Y-axis direction is in the Y-axis direction. It is desirable to be equal to the dimension DB of the pair of second connecting plates. In addition, the rotation error of the optical scanners 1 and 401 shown in FIGS. 6 to 11 when the adhesion deviation in the X-axis direction occurs was also analyzed, but the rotation error of any of the optical scanners 1 and 401 is 0.0%. Met.

  FIG. 13 shows an analysis result of a resonance frequency difference generated in each of the optical scanners 1 and 401 shown in FIGS. 6 to 11 when the adhesion deviation GP in the Y-axis direction occurs. The resonance frequency difference between the optical scanners 1 and 401 is the difference between the resonance frequency when the adhesion deviation GP occurs and the resonance frequency when the adhesion deviation GP does not occur. As shown in FIG. 13, the resonance frequency difference of the optical scanner 1 according to the present embodiment shown in FIGS. 7 to 11 is smaller than the resonance frequency difference of the conventional optical scanner 401 shown in FIG. Therefore, the optical scanner 1 according to the present embodiment has a small amount of change in the resonance frequency that occurs when the adhesive displacement occurs in the Y-axis direction, that is, the direction perpendicular to the extension line AX. In addition, although the resonance frequency difference of the optical scanners 1 and 401 shown in FIGS. 6 to 11 when the adhesion deviation in the X-axis direction occurs was also analyzed, 0.0, −0.23, and 0.28, respectively. , -0.64, 0.57, and 0.24 Hz were all very small.

  FIG. 14 shows an analysis result of the maximum stress difference generated in each of the optical scanners 1 and 401 shown in FIGS. 6 to 11 when the adhesion deviation GP in the Y-axis direction occurs. The maximum stress difference between the optical scanners 1 and 401 is the difference between the maximum stress when the adhesion deviation GP occurs and the maximum stress when the adhesion deviation GP does not occur. As shown in FIG. 14, the maximum stress difference of the optical scanner 1 according to this embodiment shown in FIGS. 7 to 11 is smaller than the maximum stress difference of the conventional optical scanner 401 shown in FIG. Therefore, the optical scanner 1 according to the present embodiment has a small amount of change in the maximum stress that occurs when an adhesion shift occurs in the Y-axis direction, that is, in a direction perpendicular to the extension line AX. In addition, the analysis of the maximum stress difference of the optical scanners 1 and 401 shown in FIGS. 6 to 11 when the adhesive displacement in the X-axis direction occurs was also performed, but 0.0, 1.22, 6.56, All were very small with 6.49, 10.73, and 10.14 MPa.

  As described above, the analysis results shown in FIGS. 12 to 14 are summarized. In the optical scanner 1 according to the present embodiment, variation in characteristics of the optical scanner such as a rotation error due to adhesion deviation is reduced as compared with the conventional optical scanner. The Further, when the separation distance SD between the pair of bases 4 in the X-axis direction is not less than the dimension DE of the second plate portion 72 in the X-axis direction and not more than the dimension DF of the first connecting plate 31 in the X-axis direction, The variation in the characteristics of the optical scanner 1 due to the adhesive displacement is remarkably reduced. Further, the separation distance SD between the pair of bases 4 in the X-axis direction is equal to the dimension DF of the first connecting plate 31 in the X-axis direction, and the dimension DA of the pair of bases 4 in the Y-axis direction is in the Y-axis direction. When the dimension DB is equal to the dimension DB of the pair of second connecting plates, the variation in the characteristics of the optical scanner 1 due to the adhesive displacement is reduced most.

[Optical scanner usage example]
An example of use of the optical scanner 1 according to this embodiment in the retinal scanning display 201 will be described with reference to FIG. The retinal scanning display 201 is a form of a head mounted display device (hereinafter referred to as “HMD”). The retinal scanning display 201 is mounted on the wearer's head and in the vicinity thereof, guides image light to the wearer's eyes, and scans the wearer's retina in a two-dimensional direction so that an image corresponding to the image information is obtained. It is comprised so that it may be visually recognized by the wearer. The optical scanner 1 according to this embodiment is used for the resonance type deflection element 261 shown in FIG. However, the control unit 9 corresponds to the horizontal scanning control circuit 262.

  The retinal scanning display 201 includes a light beam generation unit 220, a horizontal scanning unit 260, and a vertical scanning unit 280.

  The light beam generation unit 220 generates image light based on image information S supplied from the outside, and supplies the generated image light to the horizontal scanning unit 260. The horizontal scanning unit 260 scans the image light generated by the light beam generation unit 220 in the horizontal direction, and supplies the image light scanned in the horizontal direction to the vertical scanning unit 280 via the relay optical system 270. The vertical scanning unit 280 scans the image light supplied from the horizontal scanning unit 260 in the vertical direction via the relay optical system 270, and the image light scanned in the vertical direction via the relay optical system 290. To the pupil Ea.

  The light beam generation unit 220 includes a signal processing circuit 221, a light source unit 230, and a light combining unit 240. The light flux generation unit 220 in the present embodiment is an example of a light source unit of the present invention.

  The signal processing circuit 221 receives image data S supplied from the outside. Based on the image data S, the signal processing circuit 221 generates a B video signal, an R video signal, and a G video signal, which are blue, red, and green image signals that are elements for synthesizing an image, and a light source unit 230. The signal processing circuit 221 supplies a horizontal synchronization signal for driving the horizontal scanning unit 260 to the horizontal scanning unit 260 and supplies a vertical synchronization signal for driving the vertical scanning unit 280 to the vertical scanning unit 280.

  The light source unit 230 functions as an image light output unit that converts the B video signal, the R video signal, and the G video signal supplied from the signal processing circuit 221 into image light. The light source unit 230 includes a B laser 234 that generates blue image light and a B laser driver 231 that drives the B laser 234, an R laser 235 that generates red image light, and an R laser driver 232 that drives the R laser 235. A G laser 236 that generates green image light, and a G laser driver 233 that drives the G laser 236.

  The light combining unit 240 is supplied with the three image lights output from the light source unit 230, and generates arbitrary image light by combining the three image lights into one image light. The light combining unit 240 includes collimating optical systems 241, 242, and 243, dichroic mirrors 244, 245, and 246 for combining the collimated image light, and a coupling optical system 247 that guides the combined image light to the transmission cable 250. And. Laser beams emitted from the lasers 234, 235, and 236 are collimated by collimating optical systems 241, 242, and 243, respectively, and then incident on dichroic mirrors 244, 245, and 246. Thereafter, the dichroic mirrors 244, 245, and 246 selectively reflect or transmit each image light with respect to the wavelength. The collimating optical system 251 converts the image light emitted through the transmission cable 250 into parallel light and guides it to the horizontal scanning unit 260.

  The collimated image light is converted into two-dimensionally scanned image light by the horizontal scanning unit 260, the relay optical system 270, the vertical scanning unit 280, and the relay optical system 290. The horizontal scanning unit 260 reciprocally scans the image light that has been collimated by the collimating optical system 251 in the horizontal direction for image display. The relay optical system 270 is provided between the horizontal scanning unit 260 and the vertical scanning unit 280 and guides the image light scanned by the horizontal scanning unit 260 to the vertical scanning unit 280. The vertical scanning unit 280 reciprocates in the vertical direction the image light scanned in the horizontal direction by the horizontal scanning unit 260. The relay optical system 290 emits image light scanned (two-dimensionally scanned) in the horizontal direction and the vertical direction to the pupil Ea. The relay optical system 270, the relay optical system 290, and the like in this embodiment are examples of the optical system of the present invention.

  The horizontal scanning unit 260 includes a resonance type deflection element 261 and a horizontal scanning control circuit 262. The optical scanner 101 according to the second embodiment is used for the resonance type deflection element 261. The resonant deflection element 261 has a reflection surface for scanning the image light in the horizontal direction. The horizontal scanning control circuit 262 resonates the resonance type deflection element 261 based on the horizontal synchronization signal supplied from the signal processing circuit 221. The relay optical system 270 relays image light between the horizontal scanning unit 260 and the vertical scanning unit 280. The light scanned in the horizontal direction by the resonance type deflection element 261 is converged on the reflection surface of the deflection element 281 in the vertical scanning unit 280 by the relay optical system 270.

  The vertical scanning unit 280 includes a deflection element 281 and a vertical scanning control circuit 282. The deflection element 281 scans the image light guided by the relay optical system 270 in the vertical direction. The vertical scanning control circuit 282 swings the deflection element 281 based on the vertical synchronization signal supplied from the signal processing circuit 221. The image light scanned in the horizontal direction by the resonance type deflection element 261 and scanned in the vertical direction by the deflection element 281 is emitted to the relay optical system 290 as scanning image light scanned two-dimensionally.

  The relay optical system 290 relays image light between the vertical scanning unit 280 and the wearer's pupil Ea. The image light scanned in the horizontal direction by the resonance type deflection element 261 and scanned in the vertical direction by the deflection element 281 is converged on the pupil Ea of the wearer by the relay optical system 290. In this way, the wearer can visually recognize an image corresponding to the image information.

  The retinal scanning display 201 includes a resonant deflection element 261 that is the optical scanner 1. In the optical scanner 1, variations in characteristics of the optical scanner due to adhesion displacement are reduced. Accordingly, since the retinal scanning display 201 can perform high-precision optical scanning, it can perform high-quality image display.

(Second Embodiment)
A second embodiment of the present invention will be described with reference to the drawings.

[Optical scanner appearance]
Hereinafter, the external appearance of the optical scanner 301 of this embodiment will be described with reference to the drawings. FIG. 17 is a perspective view showing the appearance of the optical scanner 301 of the present embodiment. As shown in FIG. 1, the optical scanner 301 includes a movable portion 302, an outer plate 303, and a pair of bases 304. The movable part 302 in this embodiment is an example of the movable part of the present invention. The outer plate 303 in the present embodiment is an example of the outer plate of the present invention. The base 304 in this embodiment is an example of the base of the present invention.

  The movable unit 302 includes a mirror unit 305, a pair of support beams 306, a vibration member 307, and a drive unit 308. The mirror unit 305 includes a reflective surface 351. The reflection surface 351 reflects the incident light bundle. The mirror unit 305 in the present embodiment is an example of the mirror unit of the present invention. The reflective surface 351 in the present embodiment is an example of the reflective surface of the present invention.

  The pair of support beams 306 extend from both sides of the mirror unit 305 on a plane parallel to the reflection surface 351. Thereafter, the direction parallel to the extension line AX connecting the pair of support beams 306 shown in FIG. 17 is the X axis direction, the direction parallel to the reflection surface 351 and the direction perpendicular to the pair of support beams 306 is the Y axis direction, A direction perpendicular to the reflecting surface 351 is defined as the Z-axis direction. The definitions of the X-axis direction, the Y-axis direction, and the Z-axis direction are common to other drawings. The support beam 306 in this embodiment is an example of the support beam of the present invention.

  The vibration member 307 is connected to the pair of support beams 306. The vibration member 307 extends in a direction away from the mirror unit 305 in the XY plane. The vibration member 307 transmits vibration to the pair of support beams 6. The vibration member 307 in the present embodiment is an example of the vibration member of the present invention.

  The drive unit 308 is provided across the vibration member 307 and the outer plate 303. The drive unit 308 includes a piezoelectric body, and an upper electrode and a lower electrode provided above and below the piezoelectric body so as to sandwich the piezoelectric body. The drive unit 308 in this embodiment is an example of the drive unit of the present invention.

  The outer plate 303 includes a pair of first connection plates 331 and a pair of second connection plates 332. The pair of first connection plates 331 are connected to the vibration member 307. The pair of first connecting plates 331 extend in the Y-axis direction. In the XY plane, the pair of second connection plates 332 intersect and connect to both of the pair of first connection plates 331, and in the present embodiment, the pair of second connection plates 332 are vertically connected to both of the pair of first connection plates 331. The pair of second connection plates 332 are respectively positioned with the pair of first connection plates 331 interposed therebetween. A through hole 333 penetrating in the Z-axis direction is located between the pair of second connecting plates 332 and the movable portion 302. Therefore, the pair of second connection plates 332 are positioned away from the movable portion 302 in the X direction. The pair of second connection plates 332 are respectively located on both sides of the mirror unit 305 in the Y-axis direction. The pair of second connection plates 332 extend in the X axis direction. The outer plate 303 surrounds the movable part 302. The 1st connection board 331 in this embodiment is an example of the 1st connection board of the present invention. The 2nd connection board 332 in this embodiment is an example of the 2nd connection board of the present invention.

  The pair of bases 304 extends in the Y-axis direction. The pair of bases 304 are separated from each other in the X-axis direction. The pair of bases 304 is provided by being bonded to the lower surface of the outer plate 303. The base 304 in this embodiment is an example of the base of the present invention.

  The optical scanner 301 is driven in the same manner as the optical scanner 1 according to the first embodiment. That is, when a driving voltage that periodically changes is applied between the upper electrode and the lower electrode of the driving unit 308, the piezoelectric body of the driving unit 308 is displaced. The movable portion 302 is driven by this displacement. When the movable portion 302 is driven, the mirror portion 305 swings around the extension line AX.

  The analysis result by simulation is demonstrated using FIGS. 18-21. Optical scanners 501 and 601 shown in FIGS. 18 and 19 have a different structure from the optical scanner 301 according to the second embodiment shown in FIG. A base 504 on the X axis positive direction side of the optical scanner 501 shown in FIG. 18 is different from the base 304 of the optical scanner 301 shown in FIG. 20, and a base 504 on the X axis negative direction side below the first connecting plate 531. It is connected. That is, in the X-axis direction, the base 504 on the X-axis positive direction side and the base 504 on the X-axis negative direction side are not separated from each other. Further, the bases 604 of the optical scanner 601 shown in FIG. 19 are separated from each other in the Y-axis direction. On the other hand, the bases 304 of the optical scanner 301 of this embodiment shown in FIG. 20 are separated from each other in the X-axis direction.

  FIG. 21 shows an analysis result of a rotation error that occurs in each optical scanner shown in FIGS. 18 to 20 when an adhesion shift in the Y-axis direction occurs. In the present embodiment, since the pair of bases 304 are provided by being bonded to the lower surface of the outer plate 303, the fixing position is referred to as an adhesive displacement. In the simulation, the model shown in FIG. 20 was used as the model of the optical scanner of the present embodiment. However, this model is structurally different from the optical scanner 301 shown in FIG. There is. However, since the approximate structure is the same as that of the optical scanner 301 shown in FIG. 17, the same results can be said for the optical scanner 301 shown in FIG. As shown in FIG. 21, the rotation error of the optical scanner 301 shown in FIG. 20 is very small compared to the rotation errors of the optical scanners 501 and 601 shown in FIGS. Therefore, when the pair of bases 304 are separated from each other in the X-axis direction parallel to the extension line AX as in the optical scanner 301 according to the present embodiment shown in FIG. It can be seen that the rotation error is small. Further, it can be seen that the rotation error of the optical scanner 601 shown in FIG. 19 is almost as large as the rotation error of the optical scanner 501 shown in FIG. Therefore, it can be seen that when the pair of bases 304 are separated from each other in the Y-axis direction perpendicular to the extension line AX, a rotation error due to adhesion deviation in the Y-axis direction is large.

  As described above, the analysis results shown in FIG. 21 are summarized. The optical scanner 301 according to the present embodiment shown in FIG. 20 is caused by an adhesive shift as compared with the other types of optical scanners 501 and 601 shown in FIGS. Variations in the characteristics of the optical scanner, such as rotation errors, are reduced.

(Modification)
In the first and second embodiments, the bases 4 and 304 are a pair of bases 4 and 304 that are separated from each other in a direction parallel to the extension line AX. However, the present invention is not limited to this. For example, a structure having a plate-like member connecting the pair of bases below the pair of bases may be used.

  In the first and second embodiments, the drive unit includes a piezoelectric body, and an upper electrode and a lower electrode provided above and below the piezoelectric body so as to sandwich the piezoelectric body. However, the configuration is not limited to this, and the drive unit may include a piezoelectric body and an upper electrode provided on the upper side of the piezoelectric body, and may have no lower electrode. In this case, a member corresponding to the movable portion is formed of a metal such as stainless steel and also needs to serve as the lower electrode.

  In the first and second embodiments, the etching is used for the process of forming the movable part and the outer plate. However, the present invention is not limited to this, and for example, press working and electric discharge machining may be used. In addition, the aerosol deposition method was used for the lamination process of the piezoelectric material, but this is not the only case, and the vacuum deposition method, the physical vapor deposition method, the chemical vapor deposition method, or the like is used as the piezoelectric material installation treatment. May be. Further, a bulk piezoelectric element may be used for the piezoelectric body instead of the piezoelectric body laminated by the aerosol deposition method or the like. Further, the vacuum vapor deposition method is used for the upper electrode and lower electrode lamination processing, but not limited to this, for example, a physical vapor deposition method or a chemical vapor deposition method may be used.

  In the first and second embodiments, the pair of bases 4 and 304 are provided by being bonded to the lower surface of the outer plate 303. However, the present invention is not limited to this, and the pair of bases may be provided by being fixed to the lower surface of the outer plate by laser welding or clamping.

DESCRIPTION OF SYMBOLS 1 Optical scanner 2 Movable part 3 Outer plate 31 1st connection plate 32 2nd connection plate 4 Base 5 Mirror part 51 Reflecting surface 6 Support beam 7 Vibration member 71 1st plate part 72 2nd plate part 8 Drive part SD Space | interval spacing

Claims (5)

An optical scanner that reflects and scans an incident light bundle,
A mirror portion having a reflecting surface for reflecting the incident light beam;
A pair of support beams coupled to the mirror portion and extending from both sides of the mirror portion on a plane parallel to the reflecting surface;
A vibration member connected to the pair of support beams, extending in an extending direction away from the mirror portion on a plane parallel to the reflection surface, and transmitting vibration to the pair of support beams;
A drive unit provided on the vibrating member for swinging the mirror unit;
A movable part having
A first connecting plate connected to the vibrating member and extending in a direction parallel to the reflecting surface and perpendicular to the extending direction of the vibrating member; and the first connecting plate on a surface parallel to the reflecting surface. A pair of second connecting plates that are crossed and connected to the connecting plate and are located across the first connecting plate, and an outer plate that surrounds the movable part;
A pair provided to be fixed to one surface of the outer plate extending in a direction perpendicular to an extension line connecting the pair of support beams, spaced apart from each other in a direction parallel to the extension line, and extending in parallel to the reflecting surface. And an optical scanner. The vibrating member surrounds the mirror portion and the pair of support beams,
One direction side of the pair of support beams connected to each of the pair of support beams, in a direction parallel to the reflection surface and in a direction perpendicular to the extension line, from a connection portion with the pair of support beams A pair of first plate portions extending to,
A second plate portion connected to both of the pair of first plate portions and extending on a plane parallel to the reflecting surface;
The pair of first plate portions and the second plate portion are provided on the other side of the pair of support beams on a plane parallel to the reflection surface and in a direction perpendicular to the extension line,
The outer plate is
A pair of the first connecting plates connected to the second plate portion on the one-direction side and the second plate portion on the other-direction side and extending in a direction parallel to the extension line;
In a direction parallel to the extension line, the mirror part is located on both sides of the mirror part, connected to both the pair of first connection plates, and extends in a direction perpendicular to the extension line. A pair of second connecting plates;
2. The optical scanner according to claim 1, wherein the driving unit is a pair of driving units respectively provided in the second plate part on the one-direction side and the second plate part on the other-direction side. .   The distance between the pair of bases in the direction parallel to the extension line is not less than the dimension of the second plate portion and not more than the dimension of the first connecting plate in the direction parallel to the extension line. The optical scanner according to claim 2.   The distance between the pair of bases in the direction parallel to the extension line is equal to the dimension of the first connecting plate in the direction parallel to the extension line, and the pair of bases in the direction perpendicular to the extension line. 4. The optical scanner according to claim 3, wherein a dimension is equal to a dimension of the pair of second connecting plates in a direction perpendicular to the extension line. An optical scanner according to any one of claims 1 to 4,
A light source unit for supplying light to the optical scanner;
And an optical system that guides the scanning light scanned by the optical scanner to the eyes of the user.