JP6347980B2 - Optical scanning device - Google Patents

Description

  The present invention relates to an optical scanning device.

  In recent years, development of MEMS (Micro ElectroMechanical Systems) technology has progressed. One of apparatuses using MEMS technology is an optical scanning apparatus that scans light. Optical scanning devices are used in various devices such as laser printers, bar code readers, and endoscopes.

  As one of such optical scanning devices, there is a device described in Patent Document 1. In this apparatus, a reflective surface is disposed between two movable mirrors. The first movable mirror rotates about the first rotation axis, and the second movable mirror rotates about the second rotation axis. The first rotation axis and the second rotation axis are not parallel to each other. The light entering the optical scanning device is reflected by the first movable mirror and then reflected by the reflecting surface toward the second movable mirror.

Special table 2008-514777 gazette

  MEMS technology is effective for downsizing the apparatus. However, the present inventor considered that there is a limit to downsizing in the width direction (radial direction) in the optical scanning device described in Patent Document 1.

  The present invention has been made in view of the above circumstances, and an object thereof is to further reduce the size in the width direction (radial direction) in the optical scanning device.

According to the present invention, a first substrate having a first surface;
A second substrate having a second surface, wherein the second surface opposes the first surface;
A first movable reflector provided on the first surface of the first substrate and rotatable about a first rotation axis;
A first fixed reflector provided on the first surface of the first substrate;
A second movable reflector provided on the second surface of the second substrate and rotatable about a second rotation axis;
A second fixed reflector provided on the second surface of the second substrate;
With
When viewed from a direction perpendicular to the first surface,
The first rotation axis and the second rotation axis are in a direction intersecting each other;
The second fixed reflector, the first movable reflector, the second movable reflector, and the first fixed reflector are arranged in this order in the first direction,
The second fixed reflection part reflects incident light from the outside toward the first movable reflection part,
The first movable reflector reflects the incident light toward the second movable reflector,
The second movable reflector reflects the incident light toward the second fixed reflector,
The first fixed reflection unit may be an optical scanning device that reflects the incident light toward the outside.

  According to the present invention, the optical scanning device can be downsized in the width direction (radial direction).

It is sectional drawing which shows the structure of the optical scanning device which concerns on 1st Embodiment. It is a top view which shows an example of the detailed structure of a 1st movable reflection member. It is a perspective view which shows an example of a spacer member. It is a perspective view which shows the structure of the spacer member which concerns on 2nd Embodiment. It is a perspective view which shows the structure of the spacer member which concerns on 3rd Embodiment. (A) is a front view of the spacer member which concerns on 4th Embodiment, (b) is AA sectional drawing of (a). It is a figure which shows the structure of the endoscope apparatus which concerns on 5th Embodiment. It is a figure which shows the structure of the optical scanning device which concerns on a comparative example. It is the figure which looked at the principal part of the optical scanning device shown in FIG. 8 from the upper part.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all the drawings, the same reference numerals are given to the same components, and the description will be omitted as appropriate.

(First embodiment)
FIG. 1 is a cross-sectional view illustrating a configuration of an optical scanning device 10 according to the first embodiment. The optical scanning device 10 according to the present embodiment includes a first substrate 100, a second substrate 101, a first movable reflecting member 102, a first fixed reflecting member 202, a first movable reflecting member 102, and a second fixed reflecting member 204. I have. The first substrate 100 has a first surface, and the second substrate 101 has a second surface. The first surface and the second surface face each other. The first movable reflective member 102 and the first fixed reflective member 202 are provided on the first surface of the first substrate 100, and the second movable reflective member 104 and the second fixed reflective member 204 are the second surface of the second substrate 101. Is provided. The first movable reflecting member 102 can rotate around the first rotation axis, and the second movable reflecting member 104 can rotate around the second rotation axis.

  When viewed from a direction perpendicular to the first surface of the first substrate 100 (for example, the z-axis direction in FIG. 1), the first rotation axis and the second rotation axis intersect with each other (preferably at a right angle). The second fixed reflecting member 204, the first movable reflecting member 102, the second movable reflecting member 104, and the first fixed reflecting member 202 are in the first direction (for example, the x-axis direction in FIG. 1). Arranged in order. The second fixed reflecting member 204 reflects incident light from the outside (for example, the light guide unit 440) toward the first movable reflecting member 102, and the first movable reflecting member 102 reflects the incident light to the second movable reflecting member 104. Reflect towards The second movable reflecting member 104 reflects incident light toward the first fixed reflecting member 202, and the first fixed reflecting member 202 reflects incident light toward the outside. Details will be described below.

  Both the first movable reflective member 102 and the second movable reflective member 104 are formed using MEMS technology. For example, the first movable reflective member 102 is formed by processing the first substrate 100, and the second movable reflective member 104 is formed by processing the second substrate 101. In this case, both the first substrate 100 and the second substrate 101 are preferably SOI (Silicon ON Insulator) substrates. The movable reflective surfaces of the first movable reflective member 102 and the second movable reflective member 104 are both parallel to each other in the neutral state.

  The first fixed reflection member 202 is provided on the first surface of the first substrate 100, and the second fixed reflection member 204 is provided on the second surface of the second substrate 101. A first fixed reflection surface is formed on a surface of the first fixed reflection member 202 facing the second substrate 101, and a surface of the second fixed reflection member 204 facing the first substrate 100 is the first surface. 2 A fixed reflecting surface is formed. A reflective film is formed on these fixed reflective surfaces by using, for example, a vapor deposition method. The reflective film is formed using, for example, Al, Ag, or Au. Both the first fixed reflection surface and the second fixed reflection surface are inclined toward the outside of the optical scanning device 10. The first fixed reflection member 202 is formed as a member different from the first substrate 100 and then fixed to the first substrate 100. The first fixed reflecting member 202 is formed using, for example, glass or resin. The first fixed reflecting member 202 is fixed to the first substrate 100. The same applies to the second fixed reflecting member 204.

  A spacer member 500 is provided between the first surface of the first substrate 100 and the second surface of the second substrate 101. The spacer member 500 is in contact with each of the first surface of the first substrate 100 and the second surface of the second substrate 101, and defines the interval between the first substrate 100 and the second substrate 101.

  The spacer members 500 are preferably provided at least at two locations on the first substrate 100 facing each other. In this way, the first substrate 100 and the second substrate 101 can be stabilized in a state of being separated from each other. In the example shown in the drawing, the spacer member 500 is configured such that the first substrate 100 and the second substrate are more than the first movable reflective member 102, the second movable reflective member 104, the first fixed reflective member 202, and the second fixed reflective member 204. It is located near the edge of 101. The spacer member 500 may be provided continuously over the entire periphery of the edge of the first substrate 100, or may be provided as two or more members different from each other. The spacer member 500 is formed using a certain material that transmits light from the light guide portion 440 such as glass or transparent resin.

  FIG. 2 is a plan view showing an example of a detailed structure of the first movable reflecting member 102. The detailed structure of the second movable reflective member 104 is the same as the detailed structure of the first movable reflective member 102 shown in FIG. 2 except that the orientation in plan view is different by 90 °.

  The first movable reflecting member 102 shown in this figure is formed by processing one substrate, for example, a silicon substrate or an SOI substrate. The first movable reflecting member 102 includes a movable electrode 120, a support member 110, a support shaft 130, and two fixed electrodes 140. The support shaft 130 attaches the movable electrode 120 to the support member 110 and serves as a rotation axis of the movable electrode 120 (that is, a first rotation axis or a second rotation axis). The two fixed electrodes 140 are opposed to each other via the movable electrode 120, and are arranged in a direction intersecting with the rotation axis of the movable electrode 120.

  The planar shape of the movable electrode 120 is rectangular, but the side facing the fixed electrode 140 (side extending in the Y direction in FIG. 2) has a comb shape. The support member 110 faces each of two sides (sides extending in the X direction in FIG. 2) that do not face the fixed electrode 140 among the four sides of the movable electrode 120. The support shaft 130 is provided for each of the two sides of the movable electrode 120 facing the support member 110. Specifically, the support shaft 130 is connected to the center of the side of the movable electrode 120 facing the support member 110. A line connecting the two support shafts 130 serves as the rotation axis of the movable electrode 120. In the present embodiment, the support member 110, the movable electrode 120, and the support shaft 130 are integrally formed.

  A side of the fixed electrode 140 facing the movable electrode 120 has a comb-teeth shape and meshes with a comb-teeth portion of the movable electrode 120. For this reason, the area of the part which the fixed electrode 140 and the movable electrode 120 mutually oppose becomes large, As a result, the driving force of the movable electrode 120 becomes large.

  Further, a part of the fixed electrode 140 extends between the movable electrode 120 and the support member 110. The tip of the extending portion faces the support shaft 130.

  The movable electrode 120 of the first movable reflective member 102 has, for example, a movable reflective surface 122 on the upper surface. The movable reflecting surface 122 is formed, for example, by forming a metal film (for example, an Al film) on the upper surface of the movable electrode 120. Then, by changing the angle of the movable electrode 120, the reflection angle of the light incident on the movable electrode 120 is changed. The angle of the movable electrode 120 is controlled by the control unit 20.

  As described above, the rotation axis of the first movable reflecting member 102 and the rotation axis of the second movable reflecting member 104 are directed in a direction intersecting with each other (for example, a direction orthogonal to each other). Therefore, by adjusting the angle of the movable reflecting surface 122 of each of the first movable reflecting member 102 and the second movable reflecting member 104, the light emission direction can be controlled within the yz plane in FIGS.

  FIG. 3 is a perspective view showing an example of the spacer member 500. In the example shown in this drawing, the spacer member 500 is located on the optical path of the incident light, and faces the first movable reflecting member 102 with the second fixed reflecting member 204 in between in the x direction in FIG. . The spacer member 500 is made of a material that transmits incident light.

  An antireflection film 504 is provided on the surface of the spacer member 500 through which incident light is transmitted. In the example shown in this figure, the spacer member 500 has an antireflection film on both the inner surface of the optical scanning device 10 (that is, the surface facing the first fixed reflecting member 202 or the second fixed reflecting member 204) and the outer surface. 504 is provided. If it does in this way, it can control that incident light reflects when transmitting through spacer member 500. However, the antireflection film 504 may be provided only on one surface of the spacer member 500.

  Next, a method for manufacturing the optical scanning device 10 according to the present embodiment will be described. First, the first movable reflective member 102 is formed on the first substrate 100, and the second movable reflective member 104 is formed on the second substrate 101. The first movable reflecting member 102 is formed, for example, by processing the first substrate 100, and the second movable reflecting member 104 is formed, for example, by processing the second substrate 101.

  Further, the first fixed reflection member 202 is fixed to the first substrate 100, and the second fixed reflection member 204 is fixed to the second substrate 101. Next, the movable reflective surface 122 of the first movable reflective member 102, the movable reflective surface 122 of the second movable reflective member 104, the fixed reflective surface of the first fixed reflective member 202, and the fixed reflective surface of the second fixed reflective member 204, respectively. In addition, a metal film, for example, an aluminum film is formed by vapor deposition or the like.

  Next, the first substrate 100 and the second substrate 101 are opposed to each other with the spacer member 500 interposed therebetween. In this way, the optical scanning device 10 is formed.

  Next, the effect of the present embodiment will be described using the comparative example shown in FIGS. FIG. 8 is a diagram illustrating a configuration of the optical scanning device 12 according to the comparative example. FIG. 9 is a view of the main part of the optical scanning device 12 shown in FIG. 8 as viewed from above. The optical scanning device 12 according to this comparative example has the following configuration. First, both the first movable reflective member 102 and the second movable reflective member 104 are provided on the first substrate 100. One optical member 300 is provided at a position on the first substrate 100 facing the surface on which the first movable reflective member 102 and the second movable reflective member 104 are provided. When viewed from a direction perpendicular to the first substrate 100, the optical member 300 is located between the first movable reflective member 102 and the second movable reflective member 104. The surface of the optical member 300 that faces the first substrate 100 is a fixed reflecting surface 310. The fixed reflection surface 310 is parallel to the neutral movable reflection surface 122.

The incident angle from the light guide unit 440 to the movable reflective surface 122 of the first movable reflective member 102 is θ _IN , and between the movable reflective surface 122 of the first movable reflective member 102 and the movable reflective surface 122 of the second movable reflective member 104. When the distance is a and the height of the fixed reflection surface 310 is b when the movable reflection surface 122 is used as a reference, the following formula (1) is established.

  From equation (1), it can be seen that if b is reduced, a is also reduced. On the other hand, since the two movable reflecting surfaces 122 have a certain size, there is a limit to reducing the distance a. For this reason, there is a limit to reducing b, that is, reducing the width (diameter) of the optical scanning device 10.

Further, when the tilt angle of the movable reflecting surface 122 of the second movable reflecting member 104 is θ _T and the scanning angle θ _N by the second movable reflecting member 104 is satisfied, the following equation (2) is established.

From this equation (2), it can be seen that the scanning angle θ _N by the second movable reflective member 104 is proportional to the inclination angle θ _T of the movable reflective surface 122 of the second movable reflective member 104.

On the other hand, when the inclination angle of the movable reflecting surface 122 of the first movable reflecting member 102 is θ _S and the scanning angle θ _M by the first movable reflecting member 102, the following expression (3) is established.

According to this equation (3), tan θ _M is proportional to tan (π / 2−θ _IN ). Therefore, the incident angle theta _IN of the light increases, the scanning angle theta _M by the first movable reflecting member 102 becomes small.

From formula (1), in order to increase tan (π / 2−θ _IN ), it is necessary to decrease a or increase b. There is a limit to reducing a, and when b is increased, the optical scanning device 10 is increased.

For example, when θ _S is 10 degrees, θ _M is about 18.9 degrees when θ _in is 45 degrees, and θ _M is about 3.45 degrees when θ _in is 80 degrees. In this condition, when b is 1 mm, a is 2 mm.

On the other hand, in the present embodiment, the light incident on the optical scanning device 10 from the light guide unit 440 is parallel to the first substrate 100, and the light exiting from the optical scanning device 10 is also directed to the first substrate 100. Are parallel. In this case, the following equation (4) is established with respect to the scanning angle θ _M by the first movable reflecting member 102.

Here, the distance between the centers of the first movable reflective member 102 and the second movable reflective member 104 in the traveling direction of the incident light is a, and the distance between the first surface of the first substrate 100 and the second surface of the first movable reflective member 102. That is, the distance between the first movable reflective member 102 and the second movable reflective member 104 in the thickness direction of the first substrate 100 is b. For example, when θ _in is 45 degrees and b is 0.75 mm, a is 0.75 mm. Here, even if the size of the first movable reflective member 102 and the second movable reflective member 104 is 1 mm × 1 mm, the first movable reflective member 102 and the second movable reflective member 104 are configured on different substrates. It is possible to suppress physical interference between the first movable reflective member 102 and the second movable reflective member 104.

  As described above, according to the present embodiment, the first movable reflective member 102 and the second movable reflective member 104 can be brought close to each other even if the distance b between the first substrate 100 and the second substrate 101 is reduced. Therefore, the optical scanning device 10 can be reduced in size in the width direction.

(Second Embodiment)
The optical scanning device 10 according to the present embodiment has the same configuration as that of the optical scanning device 10 according to the first embodiment except for the configuration of the spacer member 500.

  FIG. 4 is a perspective view showing the configuration of the spacer member 500 according to this embodiment. In the example shown in this drawing, the spacer member 500 has a through hole 502 in a region through which incident light passes. The through hole 502 has a direction in which incident light travels, that is, a direction in which the second fixed reflective member 204, the first movable reflective member 102, the second movable reflective member 104, and the first fixed reflective member 202 are arranged (first direction). The spacer member 500 is passed through. The spacer member 500 is not provided with the antireflection film 504.

  According to this embodiment, the same effect as that of the first embodiment can be obtained. Further, since the spacer member 500 has the through hole 502 in the region through which the incident light passes, each time the incident light enters the inside of the optical scanning device 10 and when it enters the outside of the optical scanning device 10. , It is possible to suppress the incident light from being attenuated by the spacer member 500.

(Third embodiment)
The optical scanning device 10 according to the present embodiment has the same configuration as that of the optical scanning device 10 according to the first embodiment except for the configuration of the spacer member 500.

  FIG. 5 is a perspective view showing a configuration of the spacer member 500 according to the present embodiment. In the example shown in this figure, the spacer member 500 in the direction (first direction) in which the second fixed reflective member 204, the first movable reflective member 102, the second movable reflective member 104, and the first fixed reflective member 202 are arranged. Are not aligned with the second fixed reflecting member 204 and the first fixed reflecting member 202. That is, the spacer member 500 is not provided on the optical path of incident light.

  According to this embodiment, the same effect as that of the second embodiment can be obtained.

(Fourth embodiment)
The optical scanning device 10 according to the present embodiment has the same configuration as that of the optical scanning device 10 according to the second embodiment except for the configuration of the spacer member 500.

  FIG. 6A is a front view of the spacer member 500 according to this embodiment, and FIG. 6B is a cross-sectional view taken along line AA of FIG. In the example shown in this drawing, a lens 520 is fitted in the through hole 502 of the spacer member 500.

  According to the present embodiment, the spacer member 500 also serves as a holding member that holds the lens 520. Therefore, it is not necessary to separately provide a holding member for holding the lens 520. Therefore, the optical scanning device 10 can be further downsized.

(Fifth embodiment)
FIG. 7 is a diagram illustrating a configuration of an endoscope apparatus 40 according to the fifth embodiment. The endoscope apparatus 40 according to the present embodiment is an endoscopic apparatus of a confocal optical system, and includes an optical scanning device 10, a light source 420, a dichroic mirror 430, an optical fiber as a light guide unit 440, a light detection unit 450, an AD. A conversion unit 460 and an image processing unit 470 are provided. The optical scanning device 10 is accommodated in a case 410. The case 410 constitutes the distal end portion of the endoscope apparatus 40 and has a lens 412 at the distal end. The light source 420 is a laser light source such as a semiconductor that performs laser oscillation.

  In the present embodiment, the optical scanning device 10 is the same as any one of the first to fourth embodiments.

  Next, the operation of the endoscope apparatus 40 will be described. The light generated by the light source 420 is reflected by the dichroic mirror 430 and enters the light guide unit 440. The light guide unit 440 emits the incident light toward the fixed reflection surface of the second fixed reflection member 204. This light is emitted from the lens 412 toward the observation target via the second fixed reflecting member 204, the first movable reflecting member 102, the second movable reflecting member 104, and the first fixed reflecting member 202. At this time, the control unit 20 shown in FIG. 2 and the like controls the first movable reflective member 102 and the second movable reflective member 104, thereby controlling the direction of light emitted toward the observation target.

  The observation object is impregnated with phosphor molecules in advance. The phosphor molecules emit fluorescence when excited by laser light. The fluorescent light is incident on the light guide 440 via the lens 412 via the first fixed reflective member 202, the second movable reflective member 104, the first movable reflective member 102, and the second fixed reflective member 204. . The light incident on the light guide unit 440 passes through the dichroic mirror 430 and is converted into an electrical signal by the light detection unit 450. This electric signal is converted into a digital signal by the AD converter 460. The image processing unit 470 generates image data based on the digital signal generated by the AD conversion unit 460.

  According to this embodiment, the optical scanning device 10 has the same structure as any one of the first to fourth embodiments. For this reason, the optical axis of the light emitted from the endoscope apparatus 40 can be matched with the direction in which the endoscope apparatus 40 extends (that is, the direction in which the case 410 faces). Further, the diameter r of the case 410 can be reduced.

  In addition, when the through-hole 502 and the lens 520 are provided in the part located in the side which faces the observation object among the spacer members 500, the lens 412 may be abbreviate | omitted. In this case, the diameter r of the case 410 can be further reduced.

  As mentioned above, although embodiment of this invention was described with reference to drawings, these are the illustrations of this invention, Various structures other than the above are also employable.

DESCRIPTION OF SYMBOLS 10 Optical scanning device 20 Control part 100 1st board | substrate 101 2nd board | substrate 102 1st movable reflective member 104 2nd movable reflective member 110 Support member 120 Movable electrode 122 Movable reflective surface 130 Support shaft 140 Fixed electrode 202 1st fixed reflective member 204 Second fixed reflection member 300 Optical member 310 Fixed reflection surface 40 Endoscope device 410 Case 412 Lens 420 Light source 430 Dichroic mirror 440 Light guide unit 450 Light detection unit 460 AD conversion unit 470 Image processing unit 500 Spacer member 502 Through-hole 504 Reflection Prevention film 520 Lens

Claims (6)

A first substrate having a first surface;
A second substrate having a second surface, wherein the second surface opposes the first surface;
A first movable reflector provided on the first surface of the first substrate and rotatable about a first rotation axis;
A first fixed reflector provided on the first surface of the first substrate;
A second movable reflector provided on the second surface of the second substrate and rotatable about a second rotation axis;
A second fixed reflector provided on the second surface of the second substrate;
With
When viewed from a direction perpendicular to the first surface,
The first rotation axis and the second rotation axis are in a direction intersecting each other;
The second fixed reflection portion, the first movable reflection portion, the second movable reflection portion, and the first fixed reflection portion are arranged in this order in a first direction that is a traveling direction of incident light from the outside. ,
The second fixed reflecting portion reflects toward the incident light to the first movable reflector portion,
The first movable reflector reflects the incident light toward the second movable reflector,
The second movable reflector reflects the incident light toward the first fixed reflector,
The first fixed reflection unit is an optical scanning device that reflects the incident light toward the outside. The optical scanning device according to claim 1,
A spacer member in contact with each of the first surface of the first substrate and the second surface of the second substrate;
The spacer member is an optical scanning device formed of a material that transmits the incident light. The optical scanning device according to claim 2,
The spacer member is opposed to the first movable reflective portion with the second fixed reflective portion interposed therebetween in the first direction.
An optical scanning device comprising an antireflection film provided on at least one of a surface of the spacer member facing the second fixed reflecting portion and a surface opposite to the surface. The optical scanning device according to claim 1,
A spacer member in contact with each of the first surface of the first substrate and the second surface of the second substrate;
The spacer member is opposed to the first movable reflective portion with the second fixed reflective portion interposed therebetween in the first direction, and penetrates in the first direction into a region through which the incident light passes. An optical scanning device having a through hole. The optical scanning device according to claim 4.
An optical scanning device comprising a lens disposed in the through hole. The optical scanning device according to claim 1,
A spacer member in contact with each of the first surface of the first substrate and the second surface of the second substrate;
The said spacer member is an optical scanning device which is not located in a line with the said 2nd fixed reflection part and the said 1st fixed reflection part in the said 1st direction.

Images