JP5168735B2 - Optical device, optical scanner, and image forming apparatus - Google Patents

Description

  Some embodiments according to the present invention relate to an optical device, an optical scanner, and an image forming apparatus, which are manufactured by, for example, a MEMS (Micro Electro Mechanical System) technique and a movable plate reciprocates around an elastic support portion.

  This type of optical device includes, for example, a movable plate having a reflective film that is supported by a pair of elastic support portions (torsion bars) so as to be able to twist and rotate and reflects light. In order to reduce the size and increase the functionality of an apparatus including such an optical device, it is necessary to drive the movable plate at a high speed and a large deflection angle.

  However, when the movable plate is driven at a high speed and a large deflection angle, an air flow is generated in the outer periphery of the movable plate, particularly the movable plate, and dust, dust, moisture, oil, etc. are attracted to and adhere to the reflective film of the movable plate. . As a result, the reflectance of the reflective film is lowered, and there is a problem that the brightness of the reflected light is lowered. When the luminance of light from the light source is increased to prevent a decrease in the luminance of reflected light, a new problem that power consumption in the light source increases occurs. Moreover, since the energy absorbed by the optical device increases when the reflectance of the reflective film decreases, the temperature of the optical device changes depending on the energy of light absorbed without reflection. As a result, there is a problem that the resonance frequency of the optical device changes due to a temperature change, making it difficult to control the drive of the movable plate.

Conventionally, in order to solve these problems, a movable plate having a reflection film is covered with a light transmission member from the reflection film side to prevent the reflection film from being contaminated (see, for example, Patent Document 1). ).
JP 2005-173435 A

  However, in the conventional one, it is necessary to provide, for example, transmissive glass as a light transmissive member between the light source and the reflective film, and it is necessary to coat the transmissive glass with an antireflective film, which leads to an increase in cost. there were. Further, even if an antireflection film is provided on the transmissive glass, it is impossible to transmit all light from the light source. Therefore, energy loss occurs, leading to an increase in power consumption in the light source. Furthermore, the light reflected without being transmitted may be stray light.

  Some aspects of the present invention have been made in view of the above-described problems, and provide an optical device, an optical scanner, and an image forming apparatus that can prevent contamination of a reflective film without increasing power consumption. This is one of the purposes.

  An optical device according to the present invention includes a movable plate having a reflective film that reflects light, and a support portion that supports the movable plate so as to be rotatable about a predetermined axis, and the movable plate is horizontally aligned with the predetermined axis. A thin film having a length in a direction orthogonal to the length of the reflective film.

  According to such a configuration, the length of the thin film in the direction orthogonal to the predetermined axis is larger than the length of the reflective film. Here, the moment of inertia is the sum of the products of the mass of the minute portion of the object and the square of the distance from the rotation axis of the minute portion. As a result, when the movable plate is rotated around a predetermined axis, dust or dirt attracted to the movable plate by the air current adheres to a portion outside the thin reflective film, not the reflective film. On the other hand, when compared with a thin film having the same mass and having a length in a direction perpendicular to the predetermined axis in the direction perpendicular to the length of the reflecting film, the distance from the predetermined axis as the rotation axis is longer, but the thin film has a mass Is small, the moment of inertia hardly changes. Thereby, it is possible to prevent the reflection film from being stained without increasing the power consumption.

Preferably, the reflective film and the thin film are formed on the movable plate as one film.
According to such a configuration, since the reflective film and the thin film are formed as a single film on the movable plate, the film serves both as a thin film and as a reflective film. As a result, an optical device that can prevent the reflection film from being soiled without increasing power consumption can be realized at a lower cost with fewer steps.

  Preferably, the length of the movable plate in a direction perpendicular to the predetermined axis is equal to or shorter than the length of the reflective film.

  According to such a configuration, since the length of the movable plate in the direction perpendicular to the predetermined axis is equal to or less than the length of the reflection film, the length of the movable plate in the direction perpendicular to the predetermined axis is reflected with the same mass. The moment of inertia can be reduced because the distance from the predetermined axis, which is the rotation axis, is shorter than the movable plate that prevents the reflection film from being soiled by making it larger than the length of the film. As a result, the driving torque of the movable plate can be reduced, and the power consumption compared to a movable plate having the same resonance frequency and a length in the direction perpendicular to the predetermined axis in the horizontal direction is greater than the length of the reflective film. Can be reduced.

An optical scanner according to the present invention includes the above-described optical device according to the present invention.
According to this configuration, since the optical device according to the present invention described above is provided, it is possible to prevent the reflecting surface from being stained. As a result, it is possible to prevent a decrease in the reflectance of the reflecting surface and to realize an optical scanner having excellent optical characteristics capable of maintaining the brightness of the reflected light.

An image forming apparatus according to the present invention includes the above-described optical scanner according to the present invention.
According to this configuration, since the above-described optical scanner according to the present invention is provided, the luminance of the light reflected by the reflecting surface can be maintained. Thereby, an increase in power consumption in the light source can be suppressed, and an image forming apparatus having excellent drawing characteristics can be realized.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
<Optical device>
(First embodiment)
1 to 24 show a first embodiment of an optical device according to the present invention, and FIG. 1 is a plan view for explaining a configuration of the optical device according to the first embodiment of the present invention. 2 is a cross-sectional view taken along line II-II in FIG.

  As shown in FIG. 1, the optical device 1 includes a movable plate 11, a support frame 12, and a pair of elastic support portions 13 that support the movable plate 11 to be rotatable about the X axis with respect to the support frame 12. Prepare. The movable plate 11, the support frame 12, and the elastic support portion 13 are integrally formed, for example, by etching a silicon substrate.

As shown in FIG. 2, a thin film 21a made of silicon nitride (SiN), silicon oxide (SiO ₂ ), or the like is formed on the surface of the movable plate 11, and the reflective light that reflects incident light on the thin film 21a. A film 21b is formed. The mirror 2 includes a movable plate 11, a thin film 21a, and a reflective film 21b.

  In the present embodiment, the mirror 2 has a rectangular planar shape, but the present invention is not limited to this, and other shapes such as a circle, an ellipse, and a polygon may be used as long as they play a role required as a mirror of an optical device. There may be.

  A magnet 22 is bonded to the back surface of the movable plate 11 via an adhesive (not shown). The magnet 22 is magnetized in a direction orthogonal to the X axis that is the rotation center axis of the movable plate 11 when the movable plate 11 is viewed in plan. In other words, the magnet 22 has a pair of magnetic poles having opposite polarities facing each other via the X axis. The support frame 12 is joined to the holder 50, and a coil 51 for driving the movable plate 11 is disposed on the holder 50.

  The coil 51 is supplied with an alternating current that periodically changes from a power source (not shown). As a result, the coil 51 alternately generates a magnetic field directed upward (movable plate 11 side) and a magnetic field directed downward. As a result, one of the pair of magnetic poles of the magnet 22 approaches the coil 51 and the other magnetic pole moves away, and the movable plate 11 rotates around the X axis while twisting and deforming the elastic support portion 13. Be moved.

  In the present embodiment, the drive-type vibration mirror using the electromagnetic force between the magnet 22 and the coil 51 is shown. However, the present invention is not limited to this, and the optical device 1 uses a method using electrostatic attraction or a piezoelectric element. The method used may be adopted. For example, in the case of a system using electrostatic attraction, the magnet 22 is not necessary, and one or a plurality of electrodes facing the movable plate 11 are installed instead of the coil 51. Then, by applying an alternating voltage that periodically changes between the movable plate 11 and the electrode, an electrostatic attractive force acts between the movable plate 11 and the electrode, and the elastic support portion 13 is twisted and deformed. The movable plate 11 may be rotated around the X axis.

  FIG. 3 is a cross-sectional view illustrating the detailed configuration of the movable plate shown in FIG. As shown in FIG. 3, the length (hereinafter referred to as width) in the direction perpendicular to the X axis of the reflective film 21b is the area necessary for reflecting the light incident on the reflective film 21b (hereinafter referred to as effective area). ) Is set to a width W for securing. On the other hand, the width of the thin film 21a is set to be, for example, about 100 to 200 μm larger than the width W of the reflective film 21b. Here, the moment of inertia is the sum of the products of the mass of the minute portion of the object and the square of the distance from the rotation axis of the minute portion. As a result, when the movable plate 11 is rotated around the X axis, dust or dust attracted to the movable plate 11 by the air current adheres to the portion outside the reflective film 21b of the thin film 21a, not the reflective film 21b. To do. On the other hand, compared to a thin film having the same mass and a width equal to or smaller than the width of the reflective film, the distance from the X axis, which is the rotation axis, is longer, but since the mass of the thin film is small, the moment of inertia hardly changes. .

  The width of the movable plate 11 is set to be the same as the width W of the reflective film 21b. In the present embodiment, the width of the movable plate 11 is set to be the same as the width W of the reflective film 21b. However, the width is not limited to this and may be smaller than the width W of the reflective film 21b. Thereby, the distance from the X axis that is the rotation axis is shorter than the movable plate that has the same mass and prevents the contamination of the reflection film by making the width larger than the width of the reflection film. The moment of inertia can be reduced.

  Next, a manufacturing method in the first embodiment of the optical device according to the present invention will be described with reference to FIGS. First, a manufacturing method using a silicon substrate will be described. 4 to 19 are cross-sectional views illustrating an example of a method for manufacturing the optical device shown in FIG.

As shown in FIG. 4, a substrate 10 made of, for example, silicon is prepared. Then, as shown in FIG. 5, masks 31 and 32 made of silicon oxide (SiO ₂ ) are formed on both surfaces of the substrate 10 by thermal oxidation. The masks 31 and 32 may be silicon nitride (SiN).

  Next, as shown in FIG. 6, a resist 41 is formed on the mask 31 on the surface side of the substrate 10. The resist may be positive or negative. Subsequently, as shown in FIG. 7, a resist 42 is formed on the mask 32 on the back surface side of the substrate 10.

  Next, as shown in FIG. 8, the resist 42 on the back surface side of the substrate 10 is exposed and developed to form a predetermined opening pattern P <b> 2 in the resist 42. The opening pattern P2 is a pattern that opens an area other than the movable plate 11, the support frame 12, and the elastic support portion 13, for example.

  Next, as shown in FIG. 9, the mask 32 on the back surface side is etched using the resist 42 as a mask. Thereby, the opening pattern P2 of the resist 42 is transferred to the mask 32. For example, buffered hydrofluoric acid (BHF) is used for etching the mask 32.

  Next, as shown in FIG. 10, the resists 41 and 42 on both sides of the substrate are removed. For removing the resists 41 and 42, sulfuric acid washing or ashing is used.

  Next, as shown in FIG. 11, a resist 43 is formed again on the back side of the substrate 10. Further, as shown in FIG. 12, a resist 44 is formed again on the surface side of the substrate 10.

  Next, as shown in FIG. 13, the resist 44 on the surface side of the substrate 10 is exposed and developed to form a predetermined opening pattern P <b> 1 in the resist 44. The opening pattern P1 is a pattern that opens a region other than the thin film 21a, the support frame 12, and the elastic support portion 13, for example.

  Next, as shown in FIG. 14, the mask 31 on the surface side is etched using the resist 44 as a mask. Thereby, the opening pattern P1 of the resist 44 is transferred to the mask 31. For the etching of the mask 31, for example, buffered hydrofluoric acid (BHF) is used.

  Next, as shown in FIG. 15, the resists 43 and 44 on both sides of the substrate are removed. For removing the resists 43 and 44, sulfuric acid cleaning or ashing is used.

Next, as shown in FIG. 16, the substrate 10 is etched from the back surface side using masks 31 and 32. Thereby, a through-hole is formed in the substrate 10, and the pattern of the movable plate 11, the support frame 12, the elastic support portion 13, and the thin film 21a is formed. For example, dry etching is used for etching the substrate 10. Since dry etching has selectivity, the substrate 10 made of silicon is etched, and masks 31 and 32 such as silicon oxide (SiO ₂ ) remain.

  Next, as shown in FIG. 17, by removing the masks 31 and 32 while leaving a part of the mask, a thin film 21 a that is the remaining mask is formed on the surface of the movable plate 11. The thickness of the thin film 21a is, for example, about 1 μm or less.

  Next, as shown in FIG. 18, a metal film is formed on the surface of the thin film 21a, and a reflective film 21b is formed on the thin film 21a. Examples of the method for forming the metal film include vacuum deposition, sputtering, and metal foil bonding.

  Next, as shown in FIG. 19, the magnet 22 is joined and fixed to the back surface of the movable plate 11 via an adhesive (not shown).

  Although the subsequent steps are not particularly illustrated, a structure including the movable plate 11, the support frame 12, the elastic support portion 13, the thin film 21 a, and the reflective film 21 b manufactured from the single substrate 10 in this manner is attached to the holder. By attaching to 50, the optical device 1 is manufactured.

  Next, a manufacturing method using a so-called SOI substrate will be described. 20 to 24 are cross-sectional views for explaining modifications of the method of manufacturing the optical device shown in FIG.

  As shown in FIG. 20, a substrate 100 in which a first silicon layer 100a, an oxide film layer 100b, and a second silicon layer 100c are stacked is prepared. This substrate is generally called an SOI substrate.

  The first and second silicon layers 100a and 100c of the SOI substrate are etched by forming masks 31 and 32 and resists 41, 42, 43, and 44, as shown in FIG. The mask 31 having the opening pattern P1 is formed on the front surface side of the first silicon layer 100a, and the mask 32 having the opening pattern P2 is formed on the back surface side of the second silicon layer 100c. In addition, since the formation method of opening pattern P1, P2 is the same as that of above-mentioned FIGS. 5-15, illustration and its description are abbreviate | omitted.

Next, as shown in FIG. 22, etching is performed from the surface side of the second silicon layer 100 c using a mask 31. For example, dry etching is used for etching the second silicon layer 100c. Since dry etching has selectivity, the second silicon layer 100c is etched and the oxide film layer 100b and the mask 31 such as silicon oxide (SiO ₂ ) remain.

Next, as shown in FIG. 23, etching is performed from the back surface side of the first silicon layer 100a using a mask 32. For the etching of the first silicon layer 100a, for example, dry etching is used. Since dry etching has selectivity, the first silicon layer 100a is etched, and the oxide film layer 100b and the mask 32 such as silicon oxide (SiO ₂ ) remain.

  Next, as shown in FIG. 24, etching is performed using, for example, hydrofluoric acid or buffered hydrofluoric acid (BHF). As a result, a through hole is formed in the oxide film layer 100b to form the movable plate 11, the support frame 12, and the elastic support portion 13, and the thin film 21a made of the second silicon layer 100c is formed on the surface of the movable plate 11. It is formed. Thereby, the thickness of the thin film 21a becomes the same as the thickness of the silicon layer of the SOI substrate 100. Here, since the thickness of each layer of the SOI substrate can be changed with high accuracy, the thickness of the thin film 21a can be easily controlled.

The thickness of the thin film 21a is, for example, about 5 μm. Further, since hydrofluoric acid or buffered hydrofluoric acid (BHF) is used for etching, when the masks 31 and 32 are made of silicon oxide (SiO ₂ ), the masks 31 and 32 are removed together with the oxide film layer 100b. .

  Since the subsequent steps for manufacturing the optical device 1 are the same as those in FIGS. 18 and 19, the illustration and description thereof are omitted.

  In the present embodiment, the reflective film 21b is formed on the thin film 21a after the pattern of the thin film 21a or the thin film 21a is formed. However, the present invention is not limited to this, and the pattern or the thin film 21a of the thin film 21a is formed. The reflective film 21b may be formed on the surface in advance, and then the thin film 21a may be formed. In such a case, a resist such as a resin is used as a mask for protecting the reflective film 21b.

  Thus, according to the optical device 1 in the present embodiment, the width of the thin film 21a is larger than the width of the reflective film 21b. Here, the moment of inertia is the sum of the products of the mass of the minute portion of the object and the square of the distance from the rotation axis of the minute portion. As a result, when the movable plate 11 is rotated around the X axis, dust or dust attracted to the movable plate 11 by the air current adheres to the portion outside the reflective film 21b of the thin film 21a, not the reflective film 21b. To do. On the other hand, when compared with a thin film having the same mass and a width equal to or smaller than the width of the reflective film, the distance from the X axis, which is the rotation axis, is longer, but since the thin film 21a has a smaller mass, the moment of inertia is almost the same. Absent. Thereby, it is possible to prevent the reflection film 21b from being stained without increasing the power consumption.

  Further, according to the optical device 1 in the present embodiment, since the width of the movable plate 11 is equal to or less than the width of the reflection film 21b, the reflection film is contaminated by having the same mass and making the width larger than the width of the reflection film. The moment of inertia can be reduced as compared with a movable plate that prevents the above. Thereby, the driving torque of the movable plate 11 can be reduced, and the power consumption can be reduced as compared with a movable plate having the same resonance frequency and a width larger than that of the reflective film.

(Second Embodiment)
FIG. 25 thru | or FIG. 30 shows 2nd Embodiment of the optical device based on this invention, FIG. 25 is sectional drawing explaining the detailed structure of the movable plate in 2nd Embodiment of the optical device based on this invention. FIG. Note that the same components as those of the first embodiment described above are denoted by the same reference numerals, and description thereof is omitted.

  The difference between the second embodiment and the first embodiment is that an integrated film including a thin film and a reflective film is formed on the movable plate.

  That is, as shown in FIG. 25, an integral film 21 c is formed on the surface of the movable plate 11. The surface side of the integral film 21c has light reflectivity like the reflective film 21b in the first embodiment, and the width of the integral film 21c is larger than the width W as in the thin film 21a in the first embodiment. Is also set larger. Thereby, the integral film 21c serves both as the thin film 21a and as the reflective film 21b.

  Further, the width of the movable plate 11 is set to be the same as the width W although it is smaller than the width of the integral film 21c that plays a role as the reflective film 21b. Thus, as in the first embodiment, compared to a movable plate that has the same mass and prevents the dirt of the reflecting film by making the width larger than the width of the reflecting film, from the X axis that is the rotation axis Since the distance is reduced, the moment of inertia can be reduced.

  Next, a manufacturing method in the second embodiment of the optical device according to the present invention will be described with reference to FIGS. 26 to 30 are cross-sectional views for explaining an example of the manufacturing method in the second embodiment of the optical device according to the present invention.

First, as in the first embodiment, a substrate 10 made of silicon, for example, is prepared, and a mask 33 made of aluminum (Al) is formed at a predetermined position on the surface of the substrate 10 as shown in FIG. Then, as shown in FIG. 27, masks 31 and 32 made of silicon oxide (SiO ₂ ) are formed on the remaining portion on the front surface side and the back surface side of the substrate 10 by thermal oxidation. The masks 31 and 32 may be silicon nitride (SiN).

  Next, resists 41, 42, 43, and 44 are formed and etched on the substrate 10 on which the masks 31, 32, and 33 are formed, so that the opening pattern P1 is obtained as shown in FIG. The masks 31 and 33 are formed on the front surface side of the substrate 10, and the mask 32 having the opening pattern P <b> 2 is formed on the back surface side of the substrate 10. In addition, since the formation method of opening pattern P1, P2 is the same as that of above-mentioned FIGS. 6-15, illustration and its description are abbreviate | omitted.

Next, as shown in FIG. 29, the substrate 10 is etched from the back surface side using masks 31, 32 and 33. Thereby, a through-hole is formed in the substrate 10, and a pattern of the movable plate 11, the support frame 12, the elastic support portion 13, and the integral film 21c is formed. For example, dry etching is used for etching the substrate 10. Since dry etching has selectivity, the substrate 10 made of silicon is etched, and the masks 31 and 32 such as silicon oxide (SiO ₂ ) and the mask 33 made of aluminum (Al) remain.

  Next, as shown in FIG. 30, by removing the masks 31 and 32 while leaving the mask 33, an integrated film 21 c that is the remaining mask 33 is formed on the surface of the movable plate 11.

  Since the subsequent steps for manufacturing the optical device 1 are the same as those in FIGS. 18 and 19, the illustration and description thereof are omitted.

  Thus, according to the optical device 1 in this embodiment, since the reflective film 21b and the thin film 21a are formed on the movable plate 11 as the integral film 21c, the integral film 21c functions as the thin film 21a and the reflective film 21b. Also serves as a role. Thereby, the optical device 1 capable of preventing the reflection film 21b from being contaminated without increasing the power consumption can be realized at a lower cost with fewer steps.

(Optical scanner)
Since the optical device 1 includes the reflective film 21a, the optical device 1 is preferably applied to an optical scanner included in an image forming apparatus such as a laser printer, a barcode reader, a scanning confocal laser microscope, or an imaging display. Can do. Since the optical scanner according to the present invention has the same configuration as that of the optical device 1 described above, the description thereof is omitted.

  Thus, according to the optical scanner according to the present invention, since the optical device 1 according to the present invention described above is provided, it is possible to prevent the reflection film 21b from being contaminated. As a result, it is possible to prevent the reflectance of the reflective film 21b from being lowered and to realize an optical scanner having excellent optical characteristics capable of maintaining the brightness of the reflected light.

(Image forming device)
Next, an image forming apparatus according to the present invention will be described with reference to FIG. FIG. 31 is a schematic diagram illustrating an example of an image forming apparatus including an optical scanner according to the present invention.

  An image forming apparatus (imaging display) 119 shown in FIG. 31 includes an optical device 1 that is an optical scanner, light sources 191, 192, and 193 of three colors R (red), G (green), and B (blue), and a cross A dichroic prism (X prism) 194, a galvano mirror 195, a fixed mirror 196, and a screen 197 are provided.

  In such an image forming apparatus 119, light of each color is irradiated from the light sources 191, 192, 193 to the optical device 1 (reflection film 21 b) via the cross dichroic prism 194. At this time, the red light from the light source 191, the green light from the light source 192, and the blue light from the light source 193 are combined by the cross dichroic prism 194. The light reflected by the reflective film 21 b (three colors of combined light) is reflected by the galvanometer mirror 195, then by the fixed mirror 196, and irradiated on the screen 197.

  At that time, the light reflected by the reflection film 21b is scanned in the horizontal direction of the screen 197 (main scanning) by the operation of the optical device 1 (the rotation of the movable plate 11 around the X axis). On the other hand, the light reflected by the reflective film 21 b is scanned (sub-scanned) in the vertical direction of the screen 197 by the rotation of the galvano mirror 195 around the axis Y. In addition, the intensity of light output from the light sources 191, 192, and 193 of each color changes according to image information received from a host computer (not shown).

  As described above, according to the image forming apparatus 119 according to the present invention, since the optical scanner according to the present invention described above is provided, the luminance of the light reflected by the reflective film 21b can be maintained. Accordingly, an increase in power consumption in the light source can be suppressed, and an image forming apparatus 119 having excellent drawing characteristics can be realized.

  In addition, the structure of this invention is not limited only to the above-mentioned embodiment, You may add a various change within the range which does not deviate from the summary of this invention.

It is a top view explaining the structure in 1st Embodiment of the optical device which concerns on this invention. 2 is a cross-sectional view taken along line II-II in FIG. It is sectional drawing explaining the detailed structure of the movable plate shown in FIG. It is sectional drawing explaining an example of the manufacturing method of the optical device shown in FIG. It is sectional drawing explaining an example of the manufacturing method of the optical device shown in FIG. It is sectional drawing explaining an example of the manufacturing method of the optical device shown in FIG. It is sectional drawing explaining an example of the manufacturing method of the optical device shown in FIG. It is sectional drawing explaining an example of the manufacturing method of the optical device shown in FIG. It is sectional drawing explaining an example of the manufacturing method of the optical device shown in FIG. It is sectional drawing explaining an example of the manufacturing method of the optical device shown in FIG. It is sectional drawing explaining an example of the manufacturing method of the optical device shown in FIG. It is sectional drawing explaining an example of the manufacturing method of the optical device shown in FIG. It is sectional drawing explaining an example of the manufacturing method of the optical device shown in FIG. It is sectional drawing explaining an example of the manufacturing method of the optical device shown in FIG. It is sectional drawing explaining an example of the manufacturing method of the optical device shown in FIG. It is sectional drawing explaining an example of the manufacturing method of the optical device shown in FIG. It is sectional drawing explaining an example of the manufacturing method of the optical device shown in FIG. It is sectional drawing explaining an example of the manufacturing method of the optical device shown in FIG. It is sectional drawing explaining an example of the manufacturing method of the optical device shown in FIG. It is sectional drawing explaining the modification of the manufacturing method of the optical device shown in FIG. It is sectional drawing explaining the modification of the manufacturing method of the optical device shown in FIG. It is sectional drawing explaining the modification of the manufacturing method of the optical device shown in FIG. It is sectional drawing explaining the modification of the manufacturing method of the optical device shown in FIG. It is sectional drawing explaining the modification of the manufacturing method of the optical device shown in FIG. It is sectional drawing explaining the detailed structure of the movable plate in 2nd Embodiment of the optical device which concerns on this invention. It is sectional drawing explaining an example of the manufacturing method in 2nd Embodiment of the optical device which concerns on this invention. It is sectional drawing explaining an example of the manufacturing method in 2nd Embodiment of the optical device which concerns on this invention. It is sectional drawing explaining an example of the manufacturing method in 2nd Embodiment of the optical device which concerns on this invention. It is sectional drawing explaining an example of the manufacturing method in 2nd Embodiment of the optical device which concerns on this invention. It is sectional drawing explaining an example of the manufacturing method in 2nd Embodiment of the optical device which concerns on this invention. 1 is a schematic diagram illustrating an example of an image forming apparatus including an optical scanner according to the present invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Optical device, 11 ... Movable plate, 12 ... Support frame, 13 ... Elastic support part, 21a ... Thin film, 21b ... Reflective film, 119 ... Image forming apparatus.

Claims (4)

A reflective film that reflects light ;
A thin film,
A movable plate that supports the reflective film via the thin film ;
And a support portion rotatably supporting a predetermined axis around the movable plate,
In plan view, the length of the thin film in the predetermined axis and the straight intersects the first direction is characterized by longer than a length of the movable plate in the length and the first direction of the reflective film in the first direction An optical device. The optical device according to claim 1 , wherein a length of the reflective film in the first direction is equal to a length of the movable plate in the first direction . Optical scanner, characterized in that it comprises an optical device according to 請 Motomeko 1 or 2. An image forming apparatus comprising the optical scanner according to claim 3 .

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