JP4191338B2 - Photo interrupter manufacturing method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a photo interrupter in which a light emitting module and a light receiving module are incorporated in a concave resin package. Of It relates to a manufacturing method.
[0002]
[Prior art]
A photo interrupter is incorporated in, for example, a video tape recorder or a floppy disk drive, and is widely used as a sensor for detecting the presence or absence of an object between optical paths from a light emitting element to a light receiving element. Such photo-interrupters generally have a concave appearance as shown in FIG.
[0003]
To manufacture the photo interrupter shown in FIG. 12, first, the light emitting element 110A, the light receiving element 110B, and the lead terminals 120A, 120B are sealed in the primary packages 130A, 130B by molding, and the light emitting module 100A and the light receiving module 100B are then sealed. Are produced individually. Next, the modules 100A and 100B are paired so as to face each other, and then molded again so that the modules 100A and 100B are sealed by the standing parts 200A and 200B arranged on both sides, and the leads are read from the bottom surface. The secondary package 200 is formed with the tips of the terminals 120A and 120B protruding. As a result, a photo interrupter having the concave secondary package 200 as an external shape is completed.
[0004]
On the other hand, some photointerrupters are assembled so as to be press-fitted and fixed to a substrate. This type of photointerrupter has a hook-like engagement protrusion as shown in FIG. 13 or FIG.
[0005]
For example, in the photo interrupter shown in FIG. 13, a joint component 300 having engaging protrusions 300A and 300B is manufactured in advance separately from the secondary package 200 shown in FIG. Thereafter, the joint component 300 is fixed to the base portion 200C of the secondary package 200 with an adhesive or the like, thereby completing the photo interrupter including the engaging protrusions 300A and 300B with the concave secondary package 200 as an external shape. ing. Such a photo interrupter is fixed in a hook type while the tips of the engagement protrusions 300A and 300B are press-fitted into the engagement holes M1 and M2 of the substrate M.
[0006]
Further, the photo interrupter shown in FIG. 14 has an external shape such that the secondary package 200 and the joint component 300 are combined, but the substance is the light emitting module 100A and the light receiving module 100B in the upright portions 400A and 400B. For example, the case 400 has hooks 400Aa and 400Ba, and engaging projections 410A and 410B on both sides. That is, the light emitting module 100A and the light receiving module 100B are inserted into the housing spaces 400Aa and 400Ba of the case 400 with hook, and the entire photo interrupter is attached to the substrate M through the engaging protrusions 410A and 410B of the case 400 with hook. It is fixed to the hook type.
[0007]
[Problems to be solved by the invention]
Here, any of the photointerrupters shown in FIG. 13 or FIG. 14 can be fixed to the substrate M using the joint part 300 or the case 400 with the hook, which is a separate part from the secondary package 200 or the primary packages 130A and 130B. It is said that.
[0008]
However, in the case shown in FIG. 13, after forming the complicated joint component 300 having the engaging protrusions 410 </ b> A and 410 </ b> B, the joint component 300 must be fixed to the secondary package 200. In other words, after the secondary package 200 is manufactured, at least two steps of formation and fixing of the joint component 300 are required until a final product is finally obtained, and the number of man-hours increases, thereby increasing the production cost. There was a problem of inviting. Further, when the joint component 300 is fixed to the secondary package 200, one of the lead terminals 120A and 120B may abut against the joint component 300 and bend because it is handled while being held by a handling machine or the like, resulting in poor productivity. There was also a problem. Further, in order to reduce the size of the photo interrupter, two parts such as the secondary package 200 and the joint part 300 are handled separately, which is a limit in structure.
[0009]
Similarly, even in the case shown in FIG. 14, a two-stage process is required, that is, a process of forming the case 400 with the hook as a separate part and a process of inserting the light emitting module 100 </ b> A and the light receiving module 100 </ b> B into the case 400 with the hook. In the insertion process, the modules 100A and 100B or the case 400 with the hook is held. For this reason, there are problems such as an increase in production cost, bending of the lead terminals 120A and 120B, a decrease in productivity, and a difficulty in miniaturization.
[0010]
Accordingly, the present invention has been conceived under the circumstances described above, and a photo interrupter capable of easily reducing the production cost, improving the productivity, and further reducing the size, and the manufacturing method thereof. The issue is to provide
[0011]
DISCLOSURE OF THE INVENTION
In order to solve the above problems, the present invention takes the following technical means.
[0013]
Book Request Clearly The photo interrupter manufacturing method provided by the present invention is common in a posture in which a light emitting element and a light receiving element are individually sealed in a primary package to produce a light emitting module and a light receiving module, and these modules are paired to face each other. A method of manufacturing a photo interrupter that is manufactured by sealing in a secondary package of the first, wherein a first molding step of forming the primary package by molding at the time of manufacturing the light emitting module and the light receiving module; and The secondary package is formed by molding so that the light emitting module and the light receiving module are sealed and have a standing part that is lined up on both sides and a base part that connects the standing part on the bottom side to form a concave shape. 2 with respect to the molding process and the secondary package, and A third joint body having a hook-like engagement protrusion extending downward and extending downward is exposed so as to expose a portion above the upper surface of the base in the mold. And a third mold forming step that is integrally formed by the step.
[0014]
The above technical measures are taken Tafu According to the photo interrupter manufacturing method, all steps up to the formation of the primary package, the secondary package, and the tertiary joint body can be completed by molding. In particular, the production of the tertiary joint body can be completed in a convenient one-step process by molding the secondary package, so that the number of man-hours can be minimized and the production cost can be reduced. In addition, when forming each package and the tertiary joint body, it is not necessary to hold it with a handling machine or the like, and all processes are consistently performed by molding, so that productivity can be improved through the same type of manufacturing process. At the same time, the size can be easily reduced according to the shape of the cavity of the molding die.
[0015]
The tertiary joint body extends outward. After that, because it has a hook-shaped engagement protrusion that extends downward, In a photo interrupter having such a configuration as a finished product, it can be press-fitted and fixed to a substrate or the like via an engaging protrusion of a tertiary joint body.
[0016]
The primary package is integrated with lead terminals that are electrically connected to the respective elements and extend to the outside, and the leading ends of the lead terminals extend from the standing parts of the secondary package. It is generally desirable to have a configuration that is arranged so as to escape to the outside through the base. In the photo interrupter having such a configuration, electrical connection is achieved by inserting the leading end portion of the lead terminal into a through hole opened in the substrate.
[0018]
Also Good As a preferred embodiment, before starting the third molding step, a through-hole that gradually becomes smaller in diameter from the top surface to the bottom surface is formed on the base portion of the secondary package, In the third mold forming step, the through hole may be filled with a molding material as a part of the tertiary joint body.
[0019]
According to such a configuration, the mold material filled and solidified in the through hole is a part of the tertiary joint body, and after being solidified according to the shape of the through hole, it is impossible to go out of the through hole. Therefore, the tertiary joint body can be reliably integrated with the secondary package through such a through hole.
[0021]
other As a preferred embodiment of the present invention, before starting the third molding step, a buried hole having a larger diameter with respect to the bottom surface of the base portion of the secondary package is formed while the diameter is increased. In the molding process 3, the filling material may be filled and solidified as a part of the tertiary joint body in the filling hole.
[0022]
According to such a configuration, the mold material filled and solidified in the filling hole is a part of the tertiary joint body, and once solidified according to the shape of the filling hole, it is impossible to go out of the filling hole. Therefore, it is possible to integrate the tertiary joint body while securely fixing the tertiary joint body to the secondary package through such a buried hole.
[0023]
In addition, although the said through-hole or a filling hole can be formed by processing the secondary package manufactured by molding, Preferably, when forming a secondary package by molding, it depends on the shape of a through-hole or a filling hole. It is preferable to form it integrally with the secondary package by using a mold having a shape.
[0024]
further ,other As a preferable embodiment of the present invention, the second mold forming step may be configured such that a material having higher heat resistance than the mold material used in the third mold forming step is used. On the other hand, a thermosetting mold material is used in the first mold forming step, and a thermoplastic mold material is used in the second and third mold forming steps.
[0025]
According to such a configuration, when the primary package, the secondary package, and the tertiary joint body are formed by molding, the primary package, the secondary package, and the tertiary joint body are formed using the molding material in the order of high heat resistance. In other words, in each mold forming step (particularly the second and third), since the mold forming is sequentially performed at a heating temperature lower than the heating temperature in the previous step, the mold material once solidified through heating in the previous step Even if heated, it does not soften again, and a normal finished product can be obtained without deformation.
[0026]
Other features and advantages of the present invention will become more apparent from the following description of embodiments of the invention.
[0027]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be specifically described with reference to the drawings.
[0028]
FIG. 1 shows the present invention. Manufactured by the manufacturing method according to Photo-interrupter Example 2 is a cross-sectional view showing a cross section taken along line II-II in FIG. 1, FIG. 3 is a side view showing the right side portion seen from the Rs direction in FIG. 1, and FIG. 1 is a side view showing the left side portion seen from the Ls direction, FIG. 5 is a top view showing the top portion seen from the Ts direction in FIG. 1, and FIG. 6 is a bottom view showing the bottom portion seen from the Bs direction in FIG. FIG.
[0029]
As shown in these drawings, the photointerrupter A includes a light emitting module 10A and a light receiving module 10B made up of primary packages 13A and 13B, a secondary package 20 having a substantially concave shape, and a hook-shaped engagement protrusion. The tertiary joint body 30 provided with the portions 30A and 30B on both sides is integrated with each other. As shown well in FIG. 2, this photo interrupter A is capable of being fixed to a hook type by press-fitting the engaging protrusions 30A and 30B into the engaging holes M1 and M2 of the substrate M while elastically deforming them. is there.
[0030]
FIG. 7 is a perspective view showing the internal structure of the light emitting module or the light receiving module, and will be described in detail with reference to this figure. In the light emitting module 10A, for example, a light emitting element 11A such as an infrared LED (light emitting diode) is mounted on one lead terminal 12A, and then electrically connected to the other lead terminal 12A ′ via a bonding wire W. It is sealed in the primary package 13A so as to enclose the light emitting element 11A by molding. The lead terminals 12A and 12A ′ are formed by using a lead frame (not shown), and are arranged so that the tip portions 12Aa and 12Aa ′ extend from the primary package 13A while being parallel to each other. The primary package 13A is formed into a predetermined shape by molding using, for example, an epoxy resin that is one of thermosetting resins. The primary package 13A for light emission in the present embodiment is preferably one having at least light transmission characteristics in the infrared wavelength region, but of course, a type having the optimum light transmission characteristics is appropriately selected according to the wavelength of the light emitting element 11A. Basically, the primary package 13A for light emission may be transparent as long as it transmits the irradiation light from the light emitting element 11A. The primary package 13A for light emission is provided with a cylindrical bulging portion 13Aa corresponding to the light emitting element 11A so as to efficiently guide the irradiation light of the light emitting element 11A to the outside.
[0031]
On the other hand, as shown in FIG. 7, the light receiving module 10B has the same external shape as the light emitting module 10A and is manufactured separately. In the light receiving module 10B, for example, after a light receiving element 11B such as a phototransistor is mounted on one lead terminal 12B, the light receiving module 10B is electrically connected to the other lead terminal 12B ′ via a bonding wire W, and then molded by molding. It is sealed in the primary package 13B so as to enclose the light emitting element 11A. Accordingly, the lead terminals 12B and 12B ′ are also arranged in the same manner as the light emitting module 10A. Further, the primary package 13B is also formed in substantially the same shape as the light emitting module 10A by molding using, for example, an epoxy resin which is one of thermosetting resins. Note that the primary package 13B for light reception in the present embodiment is preferably one that transmits only light in a predetermined wavelength region emitted from the light emitting module 10A in order to eliminate light reception noise due to disturbance light. Of course, the type having the optimum light transmission characteristic can be selected as appropriate according to the wavelength of the light emitting element 11A. The primary package 13B for light reception is provided with a cylindrical bulging portion 13Ba corresponding to the light receiving element 11B so as to efficiently guide light from the outside to the light receiving element 11B.
[0032]
The light emitting module 10A and the light receiving module 10B are sealed in a secondary package 20 to be described later in a posture facing each other as a pair. Irradiation light from the light emitting module 10A is shown by a one-dot chain line in FIGS. The light receiving module 10B on the opposite side is reached along the optical path B outside the secondary package 20 shown. That is, according to this photo interrupter A, when an object passes so as to block the optical path B, the electrical signal from the light receiving element 10B changes, and the presence or absence of the object can be detected accordingly. is there.
[0033]
The secondary package 20 is a concave type having a standing portion 20A, 20B that seals the light emitting module 10A and the light receiving module 10B and is arranged on both sides, and a base portion 20C that connects these standing portions 20A, 20B on the bottom side. As such, it is formed by molding. The lead terminals 10A, 10A ′, 10B, and 10B ′ of the light emitting module 10A and the light receiving module 10B are arranged so as to protrude from the bottom surface side from the standing parts 20A and 20B to the base part 20C of the secondary package 20. Further, the bulging portions 13Aa and 13Ba of the primary packages 13A and 13B sealed inside are arranged on the inner side surfaces of the standing portions 20A and 20B of the secondary package 20 so as to face the outside. Further, as well shown in FIGS. 2 and 6, only the vicinity of the lead terminals 10A, 10A ′, 10B, and 10B ′ is bulged with a certain thickness on the bottom surface of the secondary package 20, and these bulges are formed. Parts other than the part 20D are formed lower than the part 20D.
[0034]
It should be noted that a rectangular through hole 20E having a gradually decreasing diameter is formed from the top surface to the bottom surface near the center of the base portion 20C. The through-hole 20E will be described in detail in a tertiary joint body 30 described later. Such a secondary package 20 is formed into a concave shape by molding using, for example, polyphenylene sulfide (PPS) which is one of thermoplastic resins. Further, the secondary package 20 has a characteristic of not transmitting light because it does not affect the internal modules 10A and 10B due to disturbance light. Therefore, the light emitting and receiving modules 10A and 10B allow light to enter and exit only through the bulging portions 13Aa and 13Ba facing the outside of the primary packages 13A and 13B. The thermoplastic resin used when molding the secondary package 20 is preferably higher in strength and heat resistance than the mold resin used for the tertiary joint body 30 described later. The reason will be described in detail in the manufacturing method described later.
[0035]
The tertiary joint body 30 is integrally formed on the bottom side of the base portion 20C of the secondary package 20 by molding so as to have engagement hooks 30A and 30B having distal end hooks extending downward from the left and right side portions. It is formed. Further, the lead terminals 10A, 10A ′, 10B, and 10B ′ of the light emitting module 10A and the light receiving module 10B are arranged so as to protrude from the bottom surface side of the tertiary joint body 30. Such a tertiary joint body 30 is formed into a predetermined shape by molding using, for example, polycarbonate (PC) which is one of thermoplastic resins. The thermoplastic resin used when molding the tertiary joint body 30 is molded by cooling after being softened at a temperature lower than the mold resin of the secondary package 20 described above, and depending on a certain amount of force. Those having excellent mechanical strength while being elastically deformed are preferred. The reason will be described in detail in the manufacturing method described later.
[0036]
A part of the thermoplastic resin used when the tertiary joint body 30 is molded is solidified in a state where the through hole 20E of the secondary package 20 is filled, whereby one of the tertiary joint bodies 30 is solidified. The part is in a state in which it cannot go out from the through hole 20 </ b> E and is integrated with the secondary package 20. Moreover, since the through-hole 20E is formed in a square shape, the tertiary joint body 30 is reliably integrated with the secondary package 20 without causing a rotational shift around the through-hole 20E. Yes. The engagement protrusions 30A and 30B of the tertiary joint body 30 are fixed so as to be press-fitted into the engagement holes M1 and M2 of the substrate M as shown in FIG. A is securely fixed. At this time, the lead terminals 10A, 10A ′, 10B, and 10B ′ protruding from the bottom surface side of the photo interrupter A are electrically connected by soldering or the like while being inserted into a through hole (not shown) of the substrate M. .
[0037]
Next, an embodiment of a method for manufacturing the photo interrupter A having the above configuration will be described with reference to the drawings.
[0038]
FIG. 8 to FIG. 10 are explanatory views for explaining an embodiment of the method for manufacturing the photo interrupter A according to the present invention, and will be described with reference again to the drawings referred to earlier. First, in the first molding step, as shown in FIG. 7, after the light emitting element 11A and the lead terminals 12A and 12A ′ are connected by the wire W or the like, the primary package 13A covers the entire light emitting element 11A. Seal. At this time, the lead terminals 12A and 12A ′ are integrated with a lead frame (not shown), and a large number of light emitting modules 10A are formed at a time by molding, with the two lead terminals 12A and 12A ′ as one set. Is done. The light emitting module 10A manufactured as described above is manufactured by a conventionally known method, and the same applies to the light receiving module 10B. Therefore, detailed description thereof is omitted. As described above, a thermosetting resin such as an epoxy resin is preferable as the mold material used for the primary packages 13A and 13B.
[0039]
Next, in the second molding step, as shown in FIG. 8, while holding the light emitting module 10A and the light receiving module 10B as a pair and facing each other, the molds D1, D2 are formed by, for example, a transfer molding method. The secondary package 20 is formed using In a state where the molds D1 and D2 are combined, a void P corresponding to the shape of the secondary package 20 is formed inside, and after the mold material is fed into the void P while being heated and compressed, After the molds D1 and D2 are released after sufficiently cooling, a concave secondary package 20 as shown in FIG. 9 is obtained. At this time, for example, as shown in FIG. 8, a through hole 20 </ b> E is opened in the base portion 20 </ b> C of the secondary package 20 by providing the mold D <b> 1 with a pyramidal projection D <b> 1 a. Further, the bulging portions 13Aa and 13Ba of the primary packages 13A and 13B are in a state where the upper surface portions thereof are in contact with the inner surface of the mold D1, so that the portions are not covered by the secondary package 20 and are flush with each other. It becomes the form that came to the outside.
[0040]
Subsequently, in the third molding step, as shown in FIG. 10, the tertiary joint body 30 is formed by, for example, an injection method using a nozzle N and a number of molds D3 to D5. In the state where the molds D3 to D5 are combined, a void P2 corresponding to the shape of the tertiary joint body 30 having the engagement protrusions 30A and 30B inside is formed. The nozzle N is in a state of being pressed against the upper portion of the through hole 20E formed in the base portion 20C of the secondary package 20, and a mold material heated and melted from the tip Na of the nozzle N through the through hole 20E is injected. . Thereafter, after sufficiently cooling, the molds D3 to D5 are released to obtain a finished product of the photo interrupter A having the engaging protrusions 30A and 30B as shown in FIG.
[0041]
Here, in FIG. 10, only three molds D3 to D5 are shown for convenience, but in order to mold a complicated shape such as the engaging projections 30A and 30B of the tertiary joint body 30, for example, a mold is used. D4 and D5 slide in the horizontal direction (direction passing through the drawing), and at least a plurality of dies are required for each of the engaging protrusions 30A and 30B. On the other hand, since the mold D3 shown in FIG. 10 forms the bottom surface portion of the photo interrupter A flatly, it only needs to be movable in the vertical direction (vertical direction in the drawing).
[0042]
Moreover, as a mold material used in the third mold molding step, a thermoplastic resin that melts at a lower temperature than the mold material used in the second mold molding step, for example, polyphenylene sulfide was used in the second mold molding step. In this case, in the third molding step, polycarbonate that exhibits melting characteristics at a lower temperature is used. The reason for this is that when the temperature is raised to the temperature heated in the previous step in the third molding step, the molding material of the secondary package 20 is melted again to cause a shape collapse.
[0043]
In the photo interrupter A thus completed through the first to third molding steps, the primary packages 13A and 13B of the light emitting and receiving modules 10A and 10B are completely placed on the upright portions 20A and 20B of the concave secondary package 20. Sealed. Further, since the tertiary joint body 30 is fixed to the base portion 20C of the secondary package 20, and further, a part of the tertiary joint body 30 is filled and solidified in the through hole 20E, the secondary package. 20 and the tertiary joint body 30 are completely integrated, and the engaging protrusions 30A and 30B are formed in the photo interrupter A.
[0044]
Therefore, according to the manufacturing method of the photo interrupter A having the above-described configuration, all the steps until the primary packages 10A and 10B and the secondary package 20 and the tertiary joint body 30 are formed are consistently completed by molding. be able to. In particular, the formation of the tertiary joint body 30 can be completed by molding the base portion 20C of the secondary package 20, so that the number of man-hours can be minimized and the production cost can be reduced. Moreover, when forming each package 10A, 10B, 20 and the tertiary joint body 30, since it is not necessary to hold | maintain with a handling machine etc., since all the processes are consistently advanced by molding, the same kind of manufacturing process is performed. As a result, productivity can be improved and miniaturization can be easily achieved in accordance with the void shapes of the molding dies D1 to D5.
[0045]
In addition, this invention is not limited to the above-mentioned embodiment.
[0046]
For example, as shown in FIG. 11 as another embodiment of the present invention, when the concave secondary package 21 is formed by molding, a filling hole 21E having a larger diameter is formed as it becomes deeper on the bottom surface side of the base portion 21C. In addition, the mold material of the tertiary joint body 31 is filled and solidified in the filling hole 21E. Even good. Also by such a filling hole 21E, the effect that the secondary package 21 and the tertiary joint body 31 are completely integrated can be achieved similarly to the through hole 20E in the above embodiment.
[0047]
Further, in the above embodiment, when the tertiary joint body 30 is formed by molding, a plurality of molds D3 to D5 are used. Various arrangements and numbers can be considered depending on design specifications. It is not limited to the form shown in FIG.
[Brief description of the drawings]
FIG. 1 The present invention Manufactured by the method Photo-interrupter Example It is the perspective view which showed.
FIG. 2 is a cross-sectional view showing a cross section taken along line II-II in FIG.
FIG. 3 is a side view showing the right side portion seen from the Rs direction in FIG. 1;
4 is a side view showing a left side portion seen from the Ls direction in FIG. 1. FIG.
5 is a top view showing an upper surface portion seen from a Ts direction in FIG. 1. FIG.
6 is a bottom view showing a bottom part seen from the Bs direction of FIG. 1. FIG.
FIG. 7 is a perspective view showing an internal structure of a light emitting module or a light receiving module.
FIG. 8 is an explanatory diagram for explaining a second mold forming step.
FIG. 9 is an explanatory view showing a state of being molded through a second mold forming step.
FIG. 10 is an explanatory diagram for explaining a third mold forming step.
FIG. 11 The present invention Manufactured by the method Photo-interrupter Other examples It is sectional drawing which showed.
FIG. 12 is a cross-sectional view showing a general shape of a conventional photo interrupter.
FIG. 13 is a cross-sectional view showing an example of a conventional photo interrupter.
FIG. 14 is a cross-sectional view showing an example of a conventional photo interrupter.
[Explanation of symbols]
10A light emitting module
10B light receiving module
11A light emitting device
11B light receiving element
13A, 13B primary package
20 Secondary package
20A, 20B Standing part
20C base
20E Through hole
30 Tertiary joint body
30A, 30B engagement protrusion
A Photo interrupter

Claims (5)

A light emitting element and a light receiving element are individually sealed in a primary package to produce a light emitting module and a light receiving module, and these modules are paired to face each other and sealed in a common secondary package. A method for manufacturing a photo interrupter, comprising:
A first molding step of forming the primary package by molding when the light emitting module and the light receiving module are manufactured;
The secondary package is formed by molding so that the light emitting module and the light receiving module are sealed and have a standing part that is arranged on both sides and a base part that connects the standing part on the bottom side to form a concave shape. A second molding step;
For the secondary package, the upper surface of the base portion and a portion of the upright portion above the upper surface of the base portion are exposed to extend outward, and then extend downward. A third mold forming step of integrally forming a tertiary joint body having a hook-shaped engagement protrusion to be formed by molding;
In a process, The manufacturing method of the photo interrupter characterized by the above-mentioned. Before starting the third mold forming step, a through-hole that gradually becomes smaller in diameter from the top surface to the bottom surface is formed in the base portion of the secondary package, while in the third mold forming step, The method for producing a photo interrupter according to claim 1 , wherein the through hole is filled and solidified with a molding material as a part of the tertiary joint body. Before starting the third molding step, while forming a filling hole that becomes larger in diameter with respect to the bottom surface of the base portion of the secondary package, in the third molding step, The method for producing a photo interrupter according to claim 1 , wherein the filling hole is filled and solidified with a molding material as a part of the tertiary joint body. In the above-mentioned second molding step, the third having high heat resistance than the molding material used in molding process is used, the production of the photo-interrupter according to any one of claims 1 to 3 Method. In the first of the molding process, the thermosetting molding material is used, in the second and third molding process, thermoplastic molding material is used, of claims 1 to 3 The manufacturing method of the photo interrupter in any one.

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