Optical module for encoder, encoder, and method for manufacturing an optical module for encoder

Abstract

The present invention provides an optical module for encoders, an encoder, and a method for manufacturing such an optical module for encoders, which enable the design to be tailored to the required performance. [Solution] The optical module 6 comprises a support 11 having a bottom wall portion 18, a photodetector 12 disposed on the surface 18a of the bottom wall portion 18 such that the photodetector surface 121a faces away from the bottom wall portion 18, an FOP 13 having an input surface 13a formed by one end face of a plurality of optical fibers and an output surface 13b formed by the other end faces of a plurality of optical fibers, disposed on the photodetector 12 such that the output surface 13b faces the photodetector surface 121a, a first resin member 14 disposed between the photodetector surface 121a and the output surface 13b and joining the FOP 13 to the photodetector 12, and a second resin member 17 disposed on the surface 18a so as to contact the photodetector 12 and the FOP 13. The materials of the first resin member 14 and the second resin member 17 are different from each other.

Description

Technical Field

[0001] The present invention relates to an optical module for an encoder, an encoder, and a method for manufacturing an optical module for an encoder.

Background Art

[0002] Patent Document 1 describes an optical encoder. In this encoder, a fiber optic plate is disposed on a light receiving element, and light emitted from a light emitting element, reflected by a rotating plate, passes through the fiber optic plate and enters the light receiving element.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] For an encoder as described above, various performances such as improving detection accuracy or stably disposing a fiber optic plate on a light receiving element may be required, and it is required to realize a design according to the required performance.

[0005] An object of the present invention is to provide an optical module for an encoder, an encoder, and a method for manufacturing such an optical module for an encoder that can realize a design according to required performance.

Means for Solving the Problems

[0006] The optical module for encoders of the present invention comprises a support having a bottom wall; a photodetector having a light-receiving surface and disposed on the surface of the bottom wall such that the light-receiving surface faces away from the bottom wall; a fiber optic plate having an input surface composed of one end face of a plurality of optical fibers and an output surface composed of the other end faces of a plurality of optical fibers, and disposed on the photodetector such that the output surface faces the light-receiving surface; a first resin member disposed between the light-receiving surface and the output surface and bonding the fiber optic plate to the photodetector; and a second resin member disposed on the surface of the bottom wall such that it contacts the photodetector and the fiber optic plate, wherein the materials of the first resin member and the second resin member are different from each other.

[0007] This encoder optical module comprises a first resin member positioned between the light-receiving surface of a photodetector and the output surface of a fiber optic plate, which joins the fiber optic plate to the photodetector, and a second resin member positioned on the surface of the bottom wall so as to contact the photodetector and the fiber optic plate. This allows the fiber optic plate to be firmly joined to the photodetector by the first resin member, and the fiber optic plate and photodetector to be reliably supported by the second resin member. Furthermore, the materials of the first resin member and the second resin member are different from each other. This increases the degree of freedom in the selection of materials for the first and second resin members, and as a result, it becomes possible to realize a design that meets the required performance. For example, the first resin member can be formed from a material with high light transmittance, and the second resin member can be formed from a material with low light transmittance. In this case, the first resin member can suppress the blocking of light from the fiber optic plate toward the photodetector, while the second resin member can block noise light toward the photodetector from the side. As a result, detection accuracy can be improved. As another example, the first resin member can be formed from a soft material, and the second resin member from a hard material. In this case, the fiber optic plate and the photodetector can be supported more reliably by the second resin member while suppressing delamination between the fiber optic plate and the photodetector, which are joined by the first resin member. As a result, the fiber optic plate can be stably positioned on the photodetector. Thus, this optical module for encoders makes it possible to realize a design that meets the required performance.

[0008] The encoder optical module further includes a wire connected to the bottom wall and the light-receiving element, and the second resin member may cover the wire. In this case, the wire can be protected from oil and physical external forces that may be scattered when the encoder is in use.

[0009] The peripheral edge of the bottom wall surface may be exposed from the second resin member. That is, the second resin member may be formed so as not to reach the peripheral edge (outer edge) of the bottom wall surface. When manufacturing an optical module for an encoder, the uncured second resin member may be placed on the surface of the bottom wall. However, if the second resin member is formed so as not to reach the peripheral edge of the bottom wall surface, it is not necessary to place a structure (e.g., a side wall) on the bottom wall to block the uncured second resin member. Therefore, the optical module for the encoder can be miniaturized.

[0010] The support further has side walls positioned on the surface of the bottom wall, and the side walls surround the light-receiving element and the second resin member when viewed from the thickness direction of the bottom wall, and the second resin member may be in contact with the side walls. In this case, during the manufacture of the optical module for the encoder, the second resin member before curing can be blocked by the side walls. Therefore, a material with low viscosity can be used as the material for the second resin member. In addition, the light-receiving element can be protected from physical contact by the side walls.

[0011] The first resin component may be an adhesive film. In this case, since the heated first resin component hardens in a relatively short time, the fiber optic plate can be precisely bonded to the photodetector by the first resin component.

[0012] The first resin component may be a die attach film. In this case, since the heated first resin component hardens in a relatively short time, the fiber optic plate can be accurately bonded to the photodetector by the first resin component.

[0013] When viewed from the thickness direction of the bottom wall, the outer edge of the first resin member may overlap with the outer edge of the fiber optic plate. In this case, since the first resin member does not protrude outside the fiber optic plate when viewed from the thickness direction of the bottom wall, the contact area between the first resin member and the second resin member can be reduced. Therefore, when the first and second resin members shrink or expand due to changes in ambient temperature, damage at the contact point between the first and second resin members can be suppressed.

[0014] The light transmittance of the second resin member may be lower than that of the first resin member. In this case, the first resin member can suppress the blocking of light from the fiber optic plate to the photodetector, while the second resin member can block noise light from the side to the photodetector. As a result, detection accuracy can be improved.

[0015] The second resin member is harder than the first resin member. In this case, the fiber optic plate and the photodetector can be supported more reliably by the second resin member while suppressing delamination between the fiber optic plate and the photodetector, which are joined by the first resin member. As a result, the fiber optic plate can be stably positioned on the photodetector.

[0016] The encoder optical module may further include an anti-reflective layer formed on the input surface of the fiber optic plate. In this case, light reflection on the input surface of the fiber optic plate can be suppressed, thereby improving detection accuracy.

[0017] The fiber optic plate has a pair of sides facing opposite directions in a direction perpendicular to the thickness direction of the bottom wall, and the second resin member may be in contact with both of the pair of sides. In this case, the second resin member can support the light-receiving element and the fiber optic plate more reliably.

[0018] The encoder of the present invention comprises a rotating plate having a light transmission pattern or a light reflection pattern, and an optical module for the encoder arranged so that light passing through the light transmission pattern or light reflected by the light reflection pattern is incident on a photodetector. With this encoder, for the reasons described above, it is possible to realize a design that meets the required performance.

[0019] The present invention provides a method for manufacturing an optical module for an encoder, comprising: a support having a bottom wall; a photodetector having a light-receiving surface; a fiber optic plate having an input surface formed by one end face of a plurality of optical fibers and an output surface formed by the other end faces of a plurality of optical fibers; a first resin member for joining the fiber optic plate to the photodetector; and a second resin member disposed on the surface of the bottom wall, wherein the method comprises, in this order: a first step of placing the photodetector on the surface of the bottom wall such that the light-receiving surface faces away from the bottom wall; a second step of placing the fiber optic plate on the photodetector such that the output surface faces the light-receiving surface, and joining the fiber optic plate to the photodetector with the first resin member disposed between the light-receiving surface and the output surface; and a third step of placing the second resin member on the surface of the bottom wall so as to be in contact with the photodetector and the fiber optic plate, wherein the materials of the first resin member and the second resin member are different from each other.

[0020] The manufacturing method for this encoder optical module includes a second step of placing a fiber optic plate on a photodetector such that its output surface faces the photodetector's light-receiving surface, and bonding the fiber optic plate to the photodetector with a first resin member placed between the light-receiving surface and the output surface; and a third step of placing the second resin member on the surface of the bottom wall so as to be in contact with the photodetector, the first resin member, and the fiber optic plate. This allows the fiber optic plate to be firmly bonded to the photodetector by the first resin member, and the fiber optic plate and photodetector to be reliably supported by the second resin member. Furthermore, the materials of the first resin member and the second resin member are different from each other. As described above, this increases the degree of freedom in selecting the materials for the first and second resin members, and as a result, it becomes possible to realize a design that meets the required performance. Furthermore, in the manufacturing method of this encoder optical module, after the second step of joining the fiber optic plate to the photodetector with the first resin member, a third step is performed in which the second resin member is placed on the surface of the bottom wall so as to be in contact with the photodetector, the first resin member, and the fiber optic plate. This makes it possible to suppress misalignment of the fiber optic plate relative to the photodetector during manufacturing, and thus suppress a decrease in yield.

[0021] The first resin component may be an adhesive film. In this case, since the heated first resin component hardens in a relatively short time, the fiber optic plate can be precisely bonded to the photodetector by the first resin component.

[0022] The first resin component may be a die attach film. In this case, since the heated first resin component hardens in a relatively short time, the fiber optic plate can be accurately bonded to the photodetector by the first resin component.

[0023] In the second step, by curing the first resin member, a fiber optic plate is joined to the light receiving element. In the third step, after the second resin member is disposed on the surface of the bottom wall portion and then cured, the viscosity of the first resin member before being cured in the second step may be lower than the viscosity of the second resin member before being cured in the third step. In this case, due to the low viscosity of the first resin member before curing, it is possible to suppress the generation of bubbles or the like in the first resin member after curing, and the fiber optic plate can be stably disposed on the light receiving element. Further, due to the high viscosity of the second resin member before curing, a configuration (for example, a side wall portion) for blocking the second resin member can be omitted, and the manufacturing efficiency can be improved.

[0024] The method for manufacturing the optical module for an encoder may further include a forming step of forming a fiber optic plate before the second step. The forming step includes a step of attaching a second base material having a plurality of portions corresponding to the first resin member to a first base material having a plurality of portions corresponding to the fiber optic plate, and a step of obtaining a plurality of fiber optic plates to which the first resin member is attached by cutting the first base material and the second base material in this order. In this case, for example, the manufacturing efficiency can be improved as compared with the case where the first resin member is individually attached to a plurality of fiber optic plates.

[0025] A third substrate having a plurality of bottom wall portions corresponding to the bottom wall part is used. In the first step, for each of the plurality of bottom wall portions, a light receiving element is disposed on the surface of the bottom wall part such that the light receiving surface faces the side opposite to the bottom wall part. In the second step, for each of the plurality of bottom wall portions, a fiber optic plate is disposed on the light receiving element such that the output surface faces the light receiving surface, and the fiber optic plate is joined to the light receiving element by a first resin member disposed between the light receiving surface and the output surface. In the third step, for each of the plurality of bottom wall portions, a second resin member is disposed on the surface of the bottom wall part so as to contact the light receiving element, the first resin member, and the fiber optic plate. The manufacturing method of the optical module for an encoder may further include a fourth step of obtaining a plurality of optical modules for an encoder by cutting the third substrate after the third step. In this case, for example, the manufacturing efficiency can be improved as compared with the case where the light receiving elements and the like are individually disposed on the plurality of fragmented bottom wall parts.

[0026] In the third step, the second resin member may be disposed on the surface of the bottom wall part such that the second resin member is separated from the boundary between the plurality of bottom wall portions. In this case, since there is no need to provide a configuration (for example, a side wall part) for blocking the second resin member before curing on the boundary, the manufacturing efficiency can be improved.

Advantages of the Invention

[0027] According to the present invention, it is possible to provide an optical module for an encoder, an encoder, and a manufacturing method of such an optical module for an encoder that can realize a design according to required performance.

Brief Description of the Drawings

[0028] [Figure 1] It is a perspective view of an encoder according to an embodiment. [Figure 2] It is a cross-sectional view of the optical module shown in FIG. Fig. 1. [Figure 3] (a) and (b) are diagrams showing a manufacturing method of the optical module. [Figure 4](a) and (b) are diagrams showing a method for manufacturing an optical module. [Figure 5] (a) and (b) are diagrams showing a method for manufacturing an optical module. [Figure 6] This is a cross-sectional view of a modified optical module. [Modes for carrying out the invention]

[0029] Embodiments of the present invention will be described in detail below with reference to the drawings. In the following description, the same or equivalent elements will be denoted by the same reference numerals, and redundant explanations will be omitted. [Encoder Configuration]

[0030] As shown in Figure 1, the encoder 1 comprises a rotating shaft 2, a rotating plate 3, a fixed plate 4, a light source 5, an optical module (optical module for encoder) 6, and a processing unit 7. The rotating shaft 2 rotates about axis A as its centerline. The encoder 1 is, for example, an absolute rotary encoder and is a device for detecting the absolute angle of an object to be measured connected to the rotating shaft 2. In this embodiment, the encoder 1 is a through-beam encoder.

[0031] The rotating plate 3 is fixed to the rotation shaft 2 and rotates together with the rotation shaft 2. The rotating plate 3 is a so-called code wheel. The rotating plate 3 is formed in a disc shape and is attached to the rotation shaft 2 at its center so as to be positioned perpendicular to the axis A. The rotating plate 3 has a light-passing pattern 3a through which light emitted from the light source 5 passes. The light-passing pattern 3a represents a predetermined pattern such as a Gray code. The light-passing pattern 3a is composed of a plurality of slits that penetrate the rotating plate 3. These slits may be empty spaces, or transparent glass portions may be placed inside the slits.

[0032] The fixed plate 4 is fixed in a position opposite the rotating plate 3. The fixed plate 4 is formed, for example, in the shape of a rectangular plate and is arranged parallel to the rotating plate 3. The fixed plate 4 has a light-passing pattern 4a that is formed to be located on a straight line connecting the light source 5 and the optical module 6. The light-passing pattern 4a is composed of a plurality of slits that penetrate the fixed plate 4. These slits may be empty spaces, or transparent glass parts may be placed inside the slits. The light source 5 is a light-emitting element such as an LED (Light Emitting Diode). The light source 5 is positioned on the opposite side of the rotating plate 3 from the optical module 6 and emits light toward the rotating plate 3.

[0033] The optical module 6 is an encoder optical module applied to the encoder 1 and is fixed to the rotating plate 3 and the fixed plate 4 at a position opposite to the light source 5. The optical module 6 has a light-receiving element 12, which will be described later, and detects light from the light source 5 using the light-receiving element 12. The processing unit 7 is, for example, a signal processing circuit, which encodes the light detection result in the light-receiving element 12 of the optical module 6 and outputs a Gray code that represents the absolute value of the rotation angle of the rotating axis 2.

[0034] In encoder 1, when the light transmission pattern 3a of the rotating plate 3 and the light transmission pattern 4a of the fixed plate 4 overlap on the straight line connecting the light source 5 and the light receiving element 12 of the optical module 6, light from the light source 5 passes through the rotating plate 3 and the fixed plate 4 and is incident on the light receiving element 12. On the other hand, when the light transmission patterns 3a and 4a do not overlap, light from the light source 5 is blocked by the rotating plate 3 and does not occur on the light receiving element 12. [Optical module configuration]

[0035] As shown in Figure 2, the optical module 6 comprises a support 11, a light-receiving element 12, a fiber optic plate 13, a first resin member 14, an anti-reflective layer 15, a wire 16, and a second resin member 17.

[0036] In this example, the support 11 is a substrate member consisting only of a bottom wall portion 18. The bottom wall portion 18 is rectangular in shape and has a flat surface 18a. The bottom wall portion 18 may be formed of, for example, glass epoxy resin. The bottom wall portion 18 has wiring (not shown) to which the wire 16 is connected. Hereinafter, the thickness direction of the bottom wall portion 18 (the direction perpendicular to the surface 18a) will be referred to as direction D1, and the direction perpendicular to direction D1 will be referred to as direction D2.

[0037] The light-receiving element 12 is a rectangular plate-shaped light-receiving chip that detects light that has passed through the light transmission pattern 3a. The light-receiving element 12 has a light-receiving section 121. The light-receiving section 121 is, for example, a photodiode or a photodiode array and has a light-receiving surface 121a on the upper surface 12a side of the light-receiving element 12. The light-receiving surface 121a is located in the central part of the upper surface 12a and constitutes a part of the upper surface 12a. The light-receiving element 12 is positioned on the surface 18a of the bottom wall 18 such that the light-receiving surface 121a faces away from the bottom wall 18. The light-receiving element 12 has a pair of sides 12b and 12c that face opposite each other in direction D2. The light-receiving element 12 converts light incident on the light-receiving surface 121a into an electrical signal and outputs the converted electrical signal to the processing unit 7. The light-receiving element 12 has wiring (not shown) to which a wire 16 for outputting an electrical signal is connected.

[0038] The fiber optic plate (hereinafter also referred to as "FOP") 13 is an optical component formed by bundling together multiple optical fibers. The FOP 13 contains, for example, tens of millions of optical fibers having a diameter of several nanometers to tens of nanometers. The FOP 13 has a rectangular parallelepiped shape and has an input surface 13a and an output surface 13b, and a pair of side surfaces 13c and 13d that connect the input surface 13a and the output surface 13b. The input surface 13a is made up of one end face of the multiple optical fibers included in the FOP 13, and the output surface 13b is made up of the other end faces of the same multiple optical fibers. In this embodiment, the input surface 13a and the output surface 13b are parallel to each other and face opposite directions in direction D1. The pair of side surfaces 13c and 13d face opposite directions in direction D2.

[0039] The FOP13 is positioned on the photodetector 12 such that its input surface 13a and output surface 13b are parallel to the photodetector 12's light-receiving surface 121a, and its output surface 13b faces the light-receiving surface 121a. Light incident on the input surface 13a of the FOP13 propagates through each optical fiber constituting the FOP13 and is emitted from the output surface 13b toward the light-receiving surface 121a. The light incident on the input surface 13a is emitted from the output surface 13b without spreading within the FOP13.

[0040] The first resin member 14 is positioned between the light-receiving surface 121a and the output surface 13b, and the FOP 13 is bonded to the light-receiving element 12. The first resin member 14 is in contact with both the light-receiving surface 121a and the output surface 13b. In this embodiment, the first resin member 14 is in contact with the entire output surface 13b and the central portion of the upper surface 12a, including the light-receiving surface 121a. The first resin member 14 is not in contact with the outer edge portion of the upper surface 12a. When viewed from direction D1, the outer edge of the first resin member 14 overlaps with the outer edge of the FOP 13, and the first resin member 14 does not protrude outside the FOP 13. In other words, when viewed from direction D1, the shape of the first resin member 14 is the same as the shape of the FOP 13.

[0041] The first resin member 14 is composed of an adhesive film, such as a die-attach film. The die-attach film is formed in a film shape and can adhere to objects to be joined on both sides. For example, the die-attach film adheres to the objects to be joined by being heated and cured.

[0042] The anti-reflective layer 15 is formed in a film-like manner on the input surface 13a and prevents light reflection on the input surface 13a. The anti-reflective layer 15 is formed over the entire input surface 13a.

[0043] Wire 16 is a bonding wire connected to the bottom wall portion 18 and the light-receiving element 12. One end of wire 16 is connected to the exposed portion on the surface 18a of the wiring of the bottom wall portion 18, and the other end of wire 16 is connected to the exposed portion on the upper surface 12a of the wiring of the light-receiving element 12. Wire 16 is curved so as to be convex toward the opposite side of the bottom wall portion 18 (the side on which the light-receiving element 12 is located relative to the bottom wall portion 18).

[0044] The second resin member 17 is positioned on the surface 18a of the bottom wall portion 18 and supports the light-receiving element 12 and the FOP 13. The second resin member 17 is positioned on both sides of the FOP 13 in direction D2. The second resin member 17 is in contact with the light-receiving element 12, the FOP 13 and the first resin member 14. More specifically, the second resin member 17 is in contact with the exposed portion of the light-receiving element 12 on the surface 18a, the exposed portion of the first resin member 14 on the upper surface 12a of the light-receiving element 12, the sides 12b, 12c, the outer edge 14a of the first resin member 14 and the sides 13c, 13d of the FOP 13. In this embodiment, the second resin member 17 is in contact with the region on the first resin member 14 side of each side 13c, 13d, but not with the region on the anti-reflective layer 15 side.

[0045] The second resin member 17 covers the wire 16. In this embodiment, the second resin member 17 covers the entire wire 16. That is, the wire 16 is not exposed from the second resin member 17. The second resin member 17 is formed so as not to extend to the peripheral edge 18b of the surface 18a. That is, the peripheral edge 18b is exposed from the second resin member 17. The peripheral edge 18b is a rectangular frame-shaped portion that extends along the outer edge of the surface 18a so as to surround the light-receiving element 12 and the second resin member 17 when viewed from direction D1, for example.

[0046] The first resin member 14 is formed from a first resin material, and the second resin member 17 is formed from a second resin material. The first resin material and the second resin material are different from each other. The first resin material may be composed of one material or multiple materials. Similarly, the second resin material may be composed of one material or multiple materials. When we say that the first resin material and the second resin material are different from each other, we mean that they are different from each other in terms of type or ratio. When we say that the first resin material and the second resin material are different from each other in terms of type, we mean that one of the first resin material and the second resin material contains at least one material that is not included in the other. Furthermore, when we say that the first resin material and the second resin material are different from each other in terms of ratio, we mean that the ratio of the materials contained in the first resin material is different from the ratio of the materials contained in the second resin material. In other words, even if the first resin material and the second resin material are composed of the same material, if the ratio of the materials is different, the first resin material and the second resin material can be said to be different from each other. Because the first resin material and the second resin material are different from each other, the first resin member 14 and the second resin member 17 have different properties (e.g., light transmittance, hardness, etc.). The first resin material is, for example, a silicone resin or an acrylic resin. The second resin material is, for example, an epoxy resin. The first resin member and the second resin material are thermosetting resins or thermoplastic resins, and are preferably thermosetting resins.

[0047] In this embodiment, the light transmittance of the second resin member 17 is lower than that of the first resin member 14. In other words, the light-shielding properties of the second resin member 17 are higher than those of the first resin member 14. In this case, light transmittance refers to the light transmittance for light with wavelengths emitted from the light source 5, for example, the light transmittance for light with wavelengths of 800 nm to 900 nm. The light transmittance of the first resin member 14 may be, for example, 90% or more, and the light transmittance of the second resin member 17 may be, for example, 5% or less.

[0048] In this embodiment, the second resin member 17 is harder than the first resin member 14. In this example, the Young's modulus of the second resin member 17 is higher than that of the first resin member 14. The Young's modulus of the first resin member 14 is, for example, 1 × 10⁻⁶. 6 It may be around Pa, and the Young's modulus of the second resin member 17 is, for example, 8 × 10 9 A Pa level would suffice. [Manufacturing method for optical modules]

[0049] The manufacturing method of the optical module 6 will be described with reference to Figures 3 to 5. Below, an example of manufacturing multiple optical modules 6 at once will be described. First, a rectangular plate-shaped substrate 20 (third substrate) is prepared (Figure 3(a)). The substrate 20 has multiple bottom wall portions 21, each corresponding to a bottom wall portion 18. The "bottom wall portion corresponding to a bottom wall portion" is the portion that becomes the bottom wall portion 18 after the cutting process of the substrate 20. The multiple bottom wall portions 21 are arranged in a grid pattern on the substrate 20, and a boundary L1 (dicing line) is set between adjacent bottom wall portions 21. The substrate 20 is cut (diced) along the boundary L1 in a later cutting process. Each bottom wall portion 21 has a surface 21a that becomes the surface 18a after the cutting process. Wiring is formed on the bottom wall portion 21, and this wiring has exposed terminals 22 on the surface 21a. The following steps are performed for each bottom wall portion 21.

[0050] Next, as shown in Figure 3(a), the light-receiving element 12 is placed on the surface 21a (surface 18a) of the bottom wall portion 21 such that the light-receiving surface 121a faces away from the bottom wall portion 21 (first step).

[0051] Next, as shown in Figure 3(b), the light-receiving element 12 and the bottom wall portion 21 are connected by a wire 16. More specifically, one end of the wire 16 is connected to the terminal 22 of the bottom wall portion 21, and the other end of the wire 16 is connected to the exposed portion on the upper surface 12a of the wiring of the light-receiving element 12.

[0052] Here, the formation process for forming the FOP13 used in the second process described later will be explained with reference to Figure 4. First, a rectangular plate-shaped substrate 30 (first substrate) is prepared (Figure 4(a)). The substrate 30 is formed by bundling together multiple optical fibers, each having multiple portions 31 corresponding to the FOP13. The "portion corresponding to the FOP" is the portion that becomes the FOP13 after the cutting process of the substrate 30. The multiple portions 31 are arranged in a grid pattern on the substrate 30, and a boundary L2 (dicing line) is set between adjacent portions 31. The substrate 20 is cut (diced) along the boundary L2 in the subsequent cutting process.

[0053] Next, as shown in Figure 4(a), a film-like substrate 40 (second substrate) is attached to one main surface of the substrate 30. The substrate 40 is an adhesive film having a plurality of portions 41, each corresponding to the first resin member 14, and in this embodiment, it is a die-attach film. The "portion corresponding to the first resin member" is the portion that becomes the first resin member 14 after the cutting process of the substrate 40. The plurality of portions 41 are arranged in a grid pattern on the substrate 40, and a common boundary L2 with the substrate 30 is set between adjacent portions 41. Each portion 41 overlaps with the corresponding portion 31. The substrate 40 is cut along the boundary L2 together with the substrate 30.

[0054] Next, a substrate 50 is formed on the other main surface of the substrate 30. The substrate 50 is a thin film having a plurality of portions 51, each corresponding to an anti-reflective layer 15. The "portions corresponding to the anti-reflective layer" are the portions that become the anti-reflective layer 15 after the cutting process of the substrate 50. The substrate 50 is formed, for example, by applying a coating treatment to the other main surface of the substrate 30. The plurality of portions 51 are arranged in a grid pattern on the substrate 50, and a common boundary L2 with the substrate 30 is set between adjacent portions 51. Each portion 51 overlaps with the corresponding portion 31. The substrate 50 is cut along the boundary L2 together with the substrate 30.

[0055] Next, as shown in Figure 4(b), multiple FOPs 13 are obtained by cutting the laminate consisting of base material 30, base material 40, and base material 50 together along the boundary L2. In this cutting process, base material 40 may be used as a fixing member to fix the laminate. For example, base material 40 may have a dicing tape on the surface opposite to base material 30 and be fixed by the dicing tape to a base (e.g., a dicing frame) on which the laminate is placed during the cutting process. The dicing tape is peeled off before the next second step is performed. In each obtained FOP 13, a first resin member 14 is attached to one side and an anti-reflective layer 15 is formed on the other side. The side of the FOP 13 to which the first resin member 14 is attached corresponds to the output surface 13b, and the side of the FOP 13 to which the anti-reflective layer 15 is formed corresponds to the input surface 13a.

[0056] Next, as shown in Figure 5(a), the FOP 13 is positioned so that its output surface 13b faces the light-receiving surface 121a of the light-receiving element 12, and the FOP 13 is bonded to the light-receiving element 12 by a first resin member 14 positioned between the light-receiving surface 121a and the output surface 13b (second step). If the first resin member 14 is a thermosetting resin, for example, the first resin member 14 is heated and cured to bond it to the light-receiving surface 121a and the output surface 13b. If the first resin member 14 is a thermoplastic resin, for example, the first resin member 14 is heated and softened, and then cured to bond the surface of the first resin member 14 to the light-receiving surface 121a and the output surface 13b. As a result, the FOP 13 is bonded to the light-receiving element 12 via the first resin member 14. For example, when the first resin material is a thermosetting resin, if acrylic resin is used as the thermosetting resin, the first resin member 14 hardens at approximately 150°C, and if silicone resin is used as the thermosetting resin, the first resin member 14 hardens at room temperature (5°C to 35°C). Furthermore, if the first resin member 14 is a thermosetting resin that hardens at room temperature, the heat treatment includes heating the first resin member 14 from a temperature lower than room temperature to a temperature higher than room temperature.

[0057] Next, as shown in Figure 5(b), the second resin member 17 is placed on the surface 18a of the bottom wall portion 18 so as to be in contact with the light-receiving element 12, the FOP 13, and the first resin member 14 (third step). In the third step, if the second resin member 17 is a thermosetting resin, for example, it is cured by heating after being placed on the surface 18a. If the second resin member 17 is a thermoplastic resin, for example, the heated and melted second resin member 17 is placed on the surface 18a and then cured. If the second resin member 17 is a thermosetting resin that hardens at room temperature, the heat treatment includes heating the first resin member 14 from a temperature lower than room temperature to a temperature above room temperature. The second resin member 17 is placed on both sides of the FOP 13 in a direction perpendicular to the thickness direction of the base material 20 so as to cover the entirety of each wire 16.

[0058] In this embodiment, the viscosity of the first resin member 14 before curing in the second step is lower than the viscosity of the second resin member 17 before curing in the third step. When the resin members are thermoplastic resins, "viscosity of the resin members before curing" refers to the viscosity when the resin members are heated and softened. Furthermore, when the first resin member 14 and the second resin member 17 are thermosetting resins that cure at a temperature higher than room temperature, the viscosity of the first resin member 14 at room temperature before curing may be, for example, 10 Pa·s or less, and the viscosity of the second resin member 17 at room temperature before curing may be, for example, 200 Pa·s or more.

[0059] In the third step, the second resin member 17 is positioned on the surface 18a of the bottom wall portion 18 so that it is separated from the boundary L1 (does not reach the boundary L1). As a result, after curing, the peripheral edge 18b of the bottom wall portion 21 (bottom wall portion 18) is exposed from the second resin member 17. In this example, the viscosity of the heated second resin member 17 is low, which prevents the second resin member 17 from reaching the boundary L1. In other words, the viscosity of the second resin member 17 is adjusted so that it does not reach the boundary L1.

[0060] Next, multiple optical modules 6 are obtained by cutting the substrate 20 along the boundary L1 (fourth step). This completes the manufacturing process of the optical modules 6. [Mechanism of Action and Effects]

[0061] The optical module 6 comprises a first resin member 14 positioned between the light-receiving surface 121a of the photodetector 12 and the output surface 13b of the FOP 13, which joins the FOP 13 to the photodetector 12, and a second resin member 17 positioned on the surface 18a of the bottom wall portion 18 so as to contact the photodetector 12 and the FOP 13. This allows the FOP 13 to be firmly joined to the photodetector 12 by the first resin member 14, and the FOP 13 and the photodetector 12 to be reliably supported by the second resin member 17. Furthermore, the materials of the first resin member 14 and the second resin member 17 are different from each other. This increases the degree of freedom in the material selection of the first resin member 14 and the second resin member 17, and as a result, it becomes possible to realize a design that meets the required performance. For example, the first resin member 14 can be formed from a material with high light transmittance, and the second resin member 17 can be formed from a material with low light transmittance. In this case, the first resin member 14 can suppress the blocking of light from the FOP 13 to the photodetector 12, while the second resin member 17 can block noise light from the side towards the photodetector 12. As a result, detection accuracy can be improved. As another example, the first resin member 14 can be formed from a soft material, and the second resin member 17 can be formed from a hard material. In this case, the second resin member 17 can more reliably support the FOP 13 and the photodetector 12 while suppressing delamination between the FOP 13 and the photodetector 12 joined by the first resin member 14. As a result, the FOP 13 can be stably positioned on the photodetector 12. As yet another example, the first resin member 14 can be formed from a material with low viscosity before curing, and the second resin member 17 can be formed from a material with high viscosity before curing. In this case, the generation of air bubbles and the like in the first resin member 14 after curing can be suppressed, allowing the FOP 13 to be stably placed on the photodetector 12. Furthermore, the structure for blocking the second resin member 17 before curing (e.g., the side wall) can be omitted, improving manufacturing efficiency. Thus, the optical module 6 makes it possible to realize a design that meets the required performance.

[0062] The second resin member 17 covers the wire 16. This protects the wire 16 from oil and physical external forces that may be scattered when the encoder 1 is in use.

[0063] The peripheral edge 18b of the surface 18a of the bottom wall portion 18 is exposed from the second resin member 17. That is, the second resin member 17 is formed so that it does not reach the peripheral edge 18b of the surface 18a of the bottom wall portion 18. When manufacturing the optical module 6, the second resin member 17 before curing may be placed on the surface 18a, but if the second resin member 17 is formed so that it does not reach the peripheral edge 18b of the surface 18a, it is not necessary to place a structure (e.g., a side wall) on the bottom wall portion 18 to block the second resin member 17 before curing. Therefore, the optical module 6 can be miniaturized. In addition, since it is not necessary to place a structure on the bottom wall portion 18 to block the second resin member 17 before curing, manufacturing efficiency can also be improved. Furthermore, since it is not necessary to place a structure on the bottom wall portion 18 to block the second resin member 17 before curing, the area of ​​the bottom wall portion 18 can be reduced, making it possible to manufacture more optical modules 6 from a single substrate 20.

[0064] The first resin member 14 is an adhesive film (die attach film). As a result, the heated first resin member 14 hardens in a relatively short time, allowing the FOP 13 to be accurately bonded to the photodetector 12 by the first resin member 14. That is, for example, if the first resin member 14 is not an adhesive film but a resin member that takes time to harden after heating, there is a risk that the position of the FOP 13 may shift while the resin material is hardening. In contrast, if the first resin member 14 is an adhesive film, the heated first resin member 14 hardens in a relatively short time, so such displacement of the FOP 13 can be suppressed, and the FOP 13 can be accurately bonded to the photodetector 12 by the first resin member 14. As a result, the yield can be improved.

[0065] When viewed from direction D1, the outer edge of the first resin member 14 overlaps with the outer edge of the FOP 13. As a result, when viewed from direction D1, the first resin member 14 does not protrude outside the FOP 13, thus reducing the contact area between the first resin member 14 and the second resin member 17. Therefore, when the first resin member 14 and the second resin member 17 undergo thermal contraction or expansion due to changes in ambient temperature, damage at the contact point between the first resin member 14 and the second resin member 17 can be suppressed.

[0066] The light transmittance of the second resin member 17 is lower than that of the first resin member 14. This prevents the light from being blocked by the first resin member 14 from being directed from the FOP 13 to the photodetector 12, while the noise light directed from the side to the photodetector 12 can be blocked by the second resin member 17. As a result, detection accuracy can be improved.

[0067] The second resin member 17 is harder than the first resin member 14. This suppresses delamination between the FOP 13 and the photodetector 12, which are joined by the first resin member 14, while allowing the FOP 13 and the photodetector 12 to be supported more securely by the second resin member 17. As a result, the FOP 13 can be stably positioned on the photodetector 12.

[0068] The optical module 6 is equipped with an anti-reflective layer 15 formed on the input surface 13a of the FOP 13. This suppresses light reflection on the input surface 13a of the FOP 13, thereby improving detection accuracy.

[0069] The FOP13 has a pair of sides 13c and 13d facing opposite directions in direction D2, and the second resin member 17 is in contact with both sides 13c and 13d. This allows for more reliable support of the light-receiving element 12 and the FOP13.

[0070] In the manufacturing method of the optical module according to the embodiment, after the second step of joining the FOP 13 to the light-receiving element 12 with the first resin member 14, a third step is performed in which the second resin member 17 is placed on the surface 18a of the bottom wall portion 18 so as to be in contact with the light-receiving element 12, the first resin member 14, and the FOP 13. This makes it possible to suppress the misalignment of the FOP 13 relative to the light-receiving element 12 during manufacturing, and to suppress a decrease in yield. That is, for example, if the first resin member 14 is omitted and the joining of the light-receiving element 12 and the FOP 13 is also performed by the second resin member 17 (when the first resin member 14 and the second resin member 17 consist of one resin member), the second resin member 17 takes a relatively long time to harden, so a misalignment of the FOP 13's position may occur while the second resin member 17 is hardening. In contrast, in the manufacturing method of the optical module according to this embodiment, the FOP 13 is bonded to the light-receiving element 12 by the first resin member 14, and then the second resin member 17 is placed on the surface 18a of the bottom wall portion 18. This suppresses misalignment of the FOP 13 and improves the yield.

[0071] In the second step, the viscosity of the first resin member 14 before curing is lower than the viscosity of the second resin member 17 before curing in the third step. As a result, the low viscosity of the first resin member 14 before curing suppresses the generation of air bubbles and the like in the first resin member 14 after curing, and the FOP 13 can be stably placed on the photodetector 12. In addition, the high viscosity of the second resin member 17 before curing eliminates the need for a structure to hold back the second resin member 17 (e.g., a side wall), thereby improving manufacturing efficiency. Furthermore, since there is no need to place a structure to hold back the second resin member 17 on the bottom wall 18, the area of ​​the bottom wall 18 can be reduced, making it possible to manufacture more optical modules 6 from a single substrate 20.

[0072] The forming process for creating the FOP13 includes, in this order, the steps of: attaching a base material 40 having multiple portions 41 corresponding to the first resin member 14 to a base material 30 having multiple portions 31 corresponding to the FOP13; and obtaining multiple FOP13 with the first resin member 14 attached by cutting the base material 30 and the base material 40. This improves manufacturing efficiency compared to, for example, the case where the first resin member 14 is attached to multiple FOP13 individually.

[0073] In the first step, for each of the multiple bottom wall portions 21, a photodetector 12 is placed on the surface 18a of the bottom wall portion 18 such that the photodetector surface 121a faces away from the bottom wall portion 18. In the second step, for each of the multiple bottom wall portions 21, an FOP 13 is placed on the photodetector 12 such that the output surface 13b faces the photodetector surface 121a, and the FOP 13 is bonded to the photodetector 12 by a first resin member 14 placed between the photodetector surface 121a and the output surface 13b. In the third step, for each of the multiple bottom wall portions 21, a second resin member 17 is placed on the surface 18a of the bottom wall portion 18 such that it is in contact with the photodetector 12, the first resin member 14, and the FOP 13. After the third step, multiple optical modules 6 are obtained by cutting the substrate 20. This improves manufacturing efficiency compared to, for example, the case where photodetectors 12 etc. are individually placed on multiple individual bottom wall portions 18.

[0074] In the third step, the second resin member 17 is positioned on the surface 18a of the bottom wall portion 18 such that it is spaced apart from the boundary L1 between the multiple bottom wall portions 21. This eliminates the need to provide a structure (e.g., a side wall portion) on the boundary L1 to hold back the second resin member 17 before it hardens, thus improving manufacturing efficiency. [Differentiation]

[0075] The optical module 6 may be configured as shown in the modified example in Figure 6. In this modified example, the support 11 further has a side wall portion 19 positioned on the surface 18a of the bottom wall portion 18. The side wall portion 19 is formed along the outer edge of the surface 18a and has a rectangular frame shape when viewed from direction D1. When viewed from direction D1, the side wall portion 19 surrounds the light-receiving element 12, FOP 13, first resin member 14, anti-reflective layer 15, wire 16, and second resin member 17. The side wall portion 19 may be formed from the same material as the bottom wall portion 18 (e.g., glass epoxy resin). In this modified example, the second resin member 17 is in contact with the inner surface 19a of the side wall portion 19, but not with the end face 19b of the side wall portion 19 opposite to the bottom wall portion 18.

[0076] Even with these modifications, it is possible to achieve a design that meets the required performance, similar to the embodiment described above. In the modified version, the support 11 further has a side wall portion 19 positioned on the surface 18a of the bottom wall portion 18, and the side wall portion 19 surrounds the light-receiving element 12 and the second resin member 17 when viewed from direction D1, with the second resin member 17 in contact with the side wall portion 19. In this case, during the manufacturing of the optical module 6, the second resin member 17 before curing can be blocked by the side wall portion 19. Therefore, a material with low viscosity can be used as the material for the second resin member 17, further increasing the degree of freedom in material selection for the first resin member 14 and the second resin member 17. In addition, the side wall portion 19 can protect the light-receiving element 12 from physical contact.

[0077] The present invention is not limited to the embodiments and modifications described above. For example, the materials and shapes of each component are not limited to those described above, but can be made from a variety of materials and shapes. For example, the first resin member 14 may be formed by curing a resin material that has been heated and melted. When viewed from direction D1, the outer edge of the first resin member 14 does not have to overlap with the outer edge of the FOP 13. The outer edge of the first resin member 14 may be located inside or outside the outer edge of the FOP 13.

[0078] The light transmittance of the second resin member 17 may be higher than that of the first resin member 14. The hardness of the second resin member 17 may be lower than that of the first resin member 14. The viscosity of the first resin member 14 heated in the second step may be higher than that of the second resin member 17 heated in the third step.

[0079] The second resin member 17 may be arranged over the entire surface 18a of the bottom wall portion 18. In this case, the peripheral edge 18b of the surface 18a does not have to be exposed from the second resin member 17. The second resin member 17 does not have to cover the entire wire 16, but may cover only a part of the wire 16. The second resin member 17 does not have to be in contact with the side wall portion 19. If the side wall portion 19 is arranged on the bottom wall portion 18, the inner portion of the surface 18a of the bottom wall portion 18 adjacent to the side wall portion 19 is the peripheral edge 18b of the surface 18a, and the peripheral edge 18b may be exposed from the second resin member 17.

[0080] In the manufacturing method of the optical module 6 according to the above embodiment, the base material 20 may be cut to obtain a plurality of bottom wall portions 18, and then the light-receiving elements 12 may be placed on the surface 18a of each bottom wall portion 18. Alternatively, the base material 30 may be cut to obtain a plurality of FOPs 13, and then the first resin member 14 and the anti-reflective layer 15 may be placed on each FOP 13.

[0081] In the above embodiment, the first resin member 14 was attached to the output surface 13b of the FOP 13, and then the FOP 13 with the first resin member 14 attached was placed on the light-receiving surface 121a of the light-receiving element 12. However, the first resin member 14 may be placed (attached) to the light-receiving surface 121a, and then the FOP 13 may be placed on the first resin member 14.

[0082] The encoder 1 may be a reflective encoder. In this case, the light source 5 is positioned on the same side as the optical module 6 with respect to the rotating plate 3. The light source 5 may be positioned, for example, on the surface 18a of the bottom wall portion 18. That is, the optical module 6 may include a light-emitting element positioned on the surface 18a of the bottom wall portion 18. The rotating plate 3 may have a light reflection pattern that reflects the light emitted from the light source 5 instead of the light transmission pattern 3a. In this case, the light emitted from the light source 5 is reflected by the light reflection pattern of the rotating plate 3 before being incident on the light-receiving element 12.

[0083] The number of light-receiving sections 121 (light-receiving surfaces 121a) of the light-receiving element 12 is not limited and may be one or more. The light-receiving element 12 may be connected to the wiring of the bottom wall portion 18 via bumps instead of wires 16. The anti-reflective layer 15 may be formed only on a part of the input surface 13a, or may be omitted. The first resin material and the second resin material may be the same as each other. [Explanation of Symbols]

[0084] 1…Encoder, 3…Rotating plate, 3a…Light transmission pattern, 5…Light source, 6…Optical module (optical module for encoder), 11…Support, 12…Photodetector, 121a…Photodetector surface, 13…FOP (Fiber Optic Plate), 13a…Input surface, 13b…Output surface, 13c,13d…Side, 14…First resin component, 15…Anti-reflective layer, 16…Wire, 17…Second resin component, 18…Bottom wall, 18a…Surface, 18b…Peripheral edge, 19…Side wall, 20…Substrate (Third substrate), 21…Bottom wall portion, 30…Substrate (First substrate), 31…Part, 40…Substrate (Second substrate), 41…Part, L1…Boundary.

Claims

1. A support having a bottom wall, A light-receiving element having a light-receiving surface, and positioned on the surface of the bottom wall such that the light-receiving surface faces away from the bottom wall; A fiber optic plate having an input surface formed by one end face of a plurality of optical fibers and an output surface formed by the other end faces of the plurality of optical fibers, and arranged on the photodetector such that the output surface faces the photodetector, A first resin member is disposed between the light-receiving surface and the output surface and joins the fiber optic plate to the light-receiving element, The system comprises a second resin member disposed on the surface of the bottom wall portion so as to contact the light-receiving element and the fiber optic plate, An encoder optical module in which the material of the first resin member and the material of the second resin member are different from each other.

2. The system further comprises a wire connected to the bottom wall and the light-receiving element, The optical module for an encoder according to claim 1, wherein the second resin member covers the wire.

3. The optical module for an encoder according to claim 1 or 2, wherein the peripheral edge of the surface of the bottom wall is exposed from the second resin member.

4. The support further has side wall portions disposed on the surface of the bottom wall portion, The side wall portion surrounds the light-receiving element and the second resin member when viewed from the thickness direction of the bottom wall portion. The optical module for an encoder according to claim 1 or 2, wherein the second resin member is in contact with the side wall portion.

5. The optical module for an encoder according to any one of claims 1 to 4, wherein the first resin member is an adhesive film.

6. The optical module for an encoder according to any one of claims 1 to 5, wherein the first resin member is a die attach film.

7. The optical module for an encoder according to any one of claims 1 to 6, wherein, when viewed from the thickness direction of the bottom wall portion, the outer edge of the first resin member overlaps with the outer edge of the fiber optic plate.

8. The optical module for an encoder according to any one of claims 1 to 7, wherein the light transmittance of the second resin member is lower than that of the first resin member.

9. The optical module for an encoder according to any one of claims 1 to 8, further comprising an anti-reflective layer formed on the input surface of the fiber optic plate.

10. The fiber optic plate has a pair of sides facing opposite directions in a direction perpendicular to the thickness direction of the bottom wall, The optical module for an encoder according to any one of claims 1 to 9, wherein the second resin member is in contact with both of the pair of sides.

11. A rotating plate having a light-transmitting pattern or a light-reflecting pattern, An encoder comprising: an optical module for an encoder according to any one of claims 1 to 10, which is arranged such that light that has passed through the light transmission pattern or light reflected by the light reflection pattern is incident on the light receiving element.

12. A method for manufacturing an optical module for an encoder, comprising: a support having a bottom wall; a photodetector having a light-receiving surface; a fiber optic plate having an input surface formed by one end face of a plurality of optical fibers and an output surface formed by the other end faces of the plurality of optical fibers; a first resin member for joining the fiber optic plate to the photodetector; and a second resin member disposed on the surface of the bottom wall, A first step is to arrange the light-receiving element on the surface of the bottom wall such that the light-receiving surface faces away from the bottom wall, A second step involves arranging the fiber optic plate on the light-receiving element such that the output surface faces the light-receiving surface, and bonding the fiber optic plate to the light-receiving element with the first resin member positioned between the light-receiving surface and the output surface. The third step is to place the second resin member on the surface of the bottom wall so as to be in contact with the light-receiving element and the fiber optic plate, in this order, A method for manufacturing an optical module for an encoder, wherein the material of the first resin member and the material of the second resin member are different from each other.

13. The method for manufacturing an optical module for an encoder according to claim 12, wherein the first resin member is an adhesive film.

14. The method for manufacturing an optical module for an encoder according to claim 12 or 13, wherein the first resin member is a die attach film.

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