JP3625066B2 - Photoelectric sensor - Google Patents

Description

  The present invention relates to a photoelectric sensor in which a light shielding plate having a light passage window such as a slit or a pinhole is disposed on the front surface of a light projecting element or a light receiving element, thereby realizing detection area limitation, disturbance light exclusion, and the like.

  Reflective and transmissive photoelectric sensors that can limit the detection area and eliminate disturbance light by arranging a light-shielding plate with light passage windows such as slits and pinholes in front of the light projecting element and light receiving element. Is already known (see, for example, Patent Document 1).

  In the reflection type photoelectric sensor, the light projecting / receiving element and the light projecting / receiving lens are often integrally held by a synthetic resin holder. In that case, a light shielding plate having a light passage window such as a slit or a pinhole is integrally formed as a part of the holder. That is, the light shielding plate with a light passage window disposed on the front surface of the light projecting / receiving element is integrally formed with the holder, and the size and shape of the light passage window are determined by the mold design.

In the transmission type photoelectric sensor, the light projector and the light receiver are separated. The light projector includes a light projecting element and a light projecting lens, which are integrally held by a synthetic resin holder. The light receiver includes a light receiving lens and a light receiving element, which are also integrally held by a synthetic resin holder. A light shielding plate having a light passage window such as a slit or a pinhole is integrally formed as a part of the holder. That is, in the projector, the light shielding plate with the light passage window disposed on the front surface of the light projecting element is formed integrally with the holder. Similarly, in the light receiver, a light shielding plate with a light passage window disposed on the front surface of the light receiving element is integrally formed with the holder. The size and shape of the light passage window are determined by the mold design.
Japanese Utility Model Publication No. 6-4848

  However, in the conventional photoelectric sensor in which the shape and size of the light passage window (slit, pinhole, etc.) on the light shielding plate is determined by the mold design at the time of manufacturing the holder, (1) light passage When a holder with a different window shape or size is required, it is necessary to manufacture a new holder. Each time the type of holder increases, parts inventory and mold depreciation costs increase. (2) New light When obtaining holders with different shapes and sizes of passing windows, it is necessary to prepare (design) drawings and arrange molds, which takes time, and (3) new shapes and sizes of light passing windows. When obtaining different holders, the unit price will be higher when the quantity used is small. (4) The position accuracy of the light passage window cannot be raised beyond the mold accuracy (for example, ± 0.05 mm). There is a problem.

  The present invention has been made paying attention to the above-mentioned problems, and the object of the present invention is to quickly and inexpensively and more accurately provide a product having a light passage window of any shape and size. An object of the present invention is to provide a photoelectric sensor with a light passage window that can be manufactured.

  Another object of the present invention is to provide a photoelectric sensor with a light passage window capable of producing a product having a light passage window of any shape and size quickly, at low cost, and with high accuracy. It is to provide a manufacturing method.

  Other objects and operational effects of the present invention will be easily understood by those skilled in the art by referring to the description of the following specification.

  The main feature of the photoelectric sensor of the present invention is that a laser processing technique is adopted for forming a light passage window for the light shielding plate. When laser processing technology is used to form the light passage window of the light projecting unit, such a photoelectric sensor includes a light projecting unit including a light projecting element and a light projecting lens, and a light receiving unit including a light receiving element and a light receiving lens. A light-shielding plate having a predetermined-shaped light passage window formed between the light projecting element and the light projection lens included in the light projecting unit, and the light passage window of the light shield plate Can be expressed as an opening formed by laser processing. On the other hand, when the laser processing technology is adopted for forming the light passage window of the light receiving unit, such a photoelectric sensor includes a light projecting unit including a light projecting element and a light projecting lens, and a light receiving unit including a light receiving element and a light receiving lens. A light-shielding plate having a predetermined-shaped light passage window formed between the light-receiving element and the light-receiving lens included in the light-receiving portion, and the light passage window of the light-shielding plate is a laser. It can be expressed as an opening formed by processing. It goes without saying that the above two expressions are satisfied even when the laser processing technique is adopted for both the light transmitting window and the light passing window of the light receiving section.

  The “light passage window of a predetermined shape” means that light passage windows of various shapes such as a slit (straight line) shape, a pinhole (small circle) shape, an ellipse shape, and a semicircular shape are possible. It is an expression that takes into account. In addition, the “light passage window” is an expression that takes into consideration that it may be a through hole or a transparent hole (for example, transparent glass) as long as light passes through.

  According to the above-described present invention, since laser processing technology having a high degree of freedom in adjusting the shape and size is introduced in the formation of the light passage window, a large amount is generated when these adjustments are imposed on the mold design. Problems such as production days, expensive molds, and increased inventory are resolved, and the accuracy of laser processing technology is higher than the molding accuracy of molds, so products with light passage windows of any shape and size can be used. It becomes possible to manufacture quickly, at low cost and with higher accuracy.

  The photoelectric sensor specified by the above two expressions may include a synthetic resin holder. In such a case, in the former photoelectric sensor, a light projecting unit including a light projecting element, a light projecting lens, and a synthetic resin holder that integrally holds them, a light receiving element, and a light receiving lens A light-shielding plate including a light-transmitting window having a predetermined shape is interposed between the light-projecting element and the light-projecting lens included in the light-projecting unit. It can be expressed that the light passage window of the plate is an opening formed by laser processing. In the latter photoelectric sensor, a light projecting unit including a light projecting element and a light projecting lens, and a light receiving unit including a light receiving element, a light receiving lens, and a synthetic resin holder that integrally holds them. A light-shielding plate having a predetermined-shaped light passage window formed between the light-receiving element and the light-receiving lens included in the light-receiving unit, and the light passage window of the light-shielding plate is opened by laser processing. It can be expressed as being formed.

  There are various options for the light shielding plate to be subjected to laser processing with respect to the relationship with the holder, structure, material, shape, and the like.

  As a first option in relation to the holder, the light shielding plate is integrally formed with the synthetic resin holder, and the light passage window of the light shielding plate is opened by drilling the light shielding plate into a predetermined shape by laser processing. It is conceivable that it is formed. If such a configuration is adopted, a holder without a light-shielding plate part (currently 90% or more of the entire order can be handled by a photoelectric sensor using this holder) and an existing holder (by using the present invention, light passing through If there are two types of molds (opening the window to an arbitrary shape and size by laser processing), it can be applied to all photoelectric sensor holders, so the design of the holder mold must be repeated each time. At least it can meet the needs of any customer.

  As a second option in relation to the holder, it is conceivable that the light shielding plate is a separate part mounted at a predetermined position of the synthetic resin holder. If such a configuration is adopted, it is possible to deal with the majority of customers by not installing a light shielding plate, while a customer who requires some light shielding plates can be equipped with a separate light shielding plate. This can be dealt with by forming a light passage window by laser processing. In addition, since the holder and the light shielding plate can be made of different materials, the hole processing accuracy can be adjusted or the light shielding plate can have an optical filter function by appropriately selecting the material of the light shielding plate.

  More specifically, the light shielding plate has a cross-sectional structure in which a metal film such as chromium is deposited on the surface of a transparent plate such as glass or plastic, and the metal film is sublimated by laser processing to be removed into a predetermined shape. Thus, the light passage window can be formed as an opening. At this time, the transparent plate constituting the light shielding plate may include an optical multilayer film (functioning as an optical filter, a polarizing plate, or the like). As another specific example, the light shielding plate is a metal plate in which the laser processing scheduled region is thinned, and the light transmission window of the light shielding plate is drilled in a predetermined shape in the thinned region by laser processing. An opening may also be formed. Here, the shape of the opening is preferably a so-called knife edge shape. Conventionally, it was difficult to form a knife edge shape because the opening was formed by resin molding etc., but in the present invention, a light passage window is produced by laser processing, so a thin metal plate, metal film deposition, thinning It is necessary to thin the processed portion with resin or the like, and as a result, the opening is necessarily equivalent to the knife edge shape. Moreover, it is also possible to employ a configuration in which the light-receiving side light-shielding plate is held in a state where the light-shielding plate is inclined.

  From another aspect, the present invention can be regarded as a method for manufacturing a photoelectric sensor including a plurality of manufacturing steps.

  The manufacturing method of the present invention captured from such a viewpoint, when focusing on the holder integration of the light shielding plate of the light projecting unit, the light projecting element housing unit, the light projecting lens housing unit, and the cavity portion connecting them, A first step of integrally molding a synthetic resin holder having a light shielding plate portion in the hollow portion and blocking a light path from the light projecting element toward the light projecting lens by injection molding, and the synthetic resin obtained by the first step After mounting the made holder on the laser processing machine with a predetermined jig, a laser beam is introduced into the cavity from the light projecting element housing part side or the light projecting lens housing part side along the light projecting light path, and the light shielding plate part is predetermined. Mounting the light projecting element and the light projecting lens on the second step of opening the light passage window by drilling into the shape, and the synthetic resin holder having the light passage window opened in the light shielding plate portion by the second step To complete the element / lens assembly. And a third step of, can be expressed as a method for manufacturing a photoelectric sensor.

  According to such a method, since the shape control of the light passage window of the light shielding plate does not depend on the mold design, it is only necessary to prepare a holder with a light shielding plate and a holder without a light shielding plate on the light projecting unit side. A photoelectric sensor including a light passage window having a shape can be manufactured quickly, at low cost, and with high accuracy.

  Paying attention to the separate parts of the light-shielding plate of the light projecting part, the light projecting element accommodating part, the light projecting lens accommodating part, the cavity connecting them, and the cavity within the cavity part are directed from the light projecting element to the light projecting lens. A first step of integrally molding a synthetic resin holder having a light shielding plate housing portion for mounting a light shielding plate for blocking an optical path by injection molding, and the light shielding plate in the synthetic resin holder obtained by the first step A second step of mounting the light shielding plate in the housing portion, and mounting the synthetic resin holder with the light shielding plate obtained in the second step on the laser processing machine with a predetermined jig, and then the light projecting element housing portion in the cavity portion A third step of opening the light passage window by introducing a laser beam along the light projecting light path from the side or the light projecting lens housing portion and laser processing the light shielding plate into a predetermined shape; and a third step The light passage window opens on the shading plate. And a fourth step of mounting the light projecting element and a projection lens formed of synthetic resin holder to complete the device and lens assembly, can be expressed as a method for manufacturing a photoelectric sensor.

  According to such a method, in addition to not relying on the mold design to control the shape of the light passage window of the light shielding plate, a common holder can be used in combination with a light shielding plate application and a light shielding plate-free application, thereby further reducing costs. In addition, since the light shielding plate and the holder can be made of different materials, the processing accuracy of the light passage window can be improved if the light shielding plate material is selected in consideration of laser processability. Furthermore, if a transparent plate with a metal film is employed as the light shielding plate and an optical multilayer film is included in the transparent plate, the filter and the light shielding plate can be shared.

  Focusing on the holder integration of the light-shielding plate of the light-receiving part, the light-receiving lens housing part, the light-receiving element housing part, the cavity connecting them, and the light-shielding plate that shields the optical path from the light-receiving lens toward the light-receiving element in the cavity part A first step of integrally molding a synthetic resin holder having a portion by injection molding, and mounting the synthetic resin holder obtained by the first step on a laser processing machine with a predetermined jig, A second step of forming a light passage window by introducing a laser beam along the light receiving optical path from the light receiving lens housing part side or the light receiving element housing part side to perforate the light shielding plate part into a predetermined shape; And a third step of completing the element / lens assembly by mounting the light receiving element and the light receiving lens on the synthetic resin holder in which the light passage window is formed in the light shielding plate by the step. It can be expressed as a method.

  According to such a method, since the shape control of the light passage window of the light shielding plate does not depend on the mold design, an arbitrary shape can be formed on the light receiving unit side only by preparing a holder with a light shielding plate and a holder without a light shielding plate. A photoelectric sensor having a light passage window having the above can be manufactured quickly, at low cost, and with high accuracy.

  When the light shielding plate is molded in an inclined state, a step of measuring the coordinates of two points on the light shielding plate and calculating the inclination angle of the light shielding plate based on the coordinates before performing laser processing in the second step. Including.

  According to such a method, the shape control of the light passage window of the light shielding plate does not depend on the mold design, and the distance limitation is high, and the photoelectric sensor can be manufactured.

  Paying attention to the separate parts of the light-shielding plate of the light-receiving part, the light-receiving element accommodating part, the light-receiving lens accommodating part, the cavity connecting them, and the light-shielding plate that shields the optical path from the light-receiving lens toward the light-receiving element in the cavity A first step of integrally molding a synthetic resin holder having a light shielding plate housing portion for mounting a plastic plate by injection molding, and a light shielding plate on the light shielding plate housing portion in the synthetic resin holder obtained by the first step After mounting the synthetic resin holder with the light shielding plate obtained in the second step to the laser processing machine with a predetermined jig, the light receiving lens accommodating portion side or the light receiving element accommodating portion is placed in the cavity portion. A third step of opening the light passage window by introducing a laser beam from the side along the light receiving optical path and laser processing the light shielding plate into a predetermined shape, and the third step opens the light passage window to the light shielding plate. And a fourth step of mounting the light-receiving lens and a light receiving element formed of synthetic resin holder to complete the device and lens assembly, can be expressed as a method for manufacturing a photoelectric sensor.

  According to such a method, in addition to not relying on the mold design to control the shape of the light passage window of the light shielding plate, a common holder can be used in combination with a light shielding plate application and a light shielding plate-free application, thereby further reducing costs. In addition, since the light shielding plate and the holder can be made of different materials, the processing accuracy of the light passage window can be improved if the light shielding plate material is selected in consideration of laser processability. Furthermore, if a transparent plate with a metal film is employed as the light shielding plate and an optical multilayer film is included in the transparent plate, the filter and the light shielding plate can be shared.

  When the light shielding plate is held in an inclined state, before performing laser processing in the third step, a step of measuring coordinates of two points on the light shielding plate and calculating an inclination angle of the light shielding plate based on the coordinates is performed. Including.

  As is apparent from the above description, according to the present invention, a light passage window capable of manufacturing a product having a light passage window of an arbitrary shape and size quickly, at low cost and with higher accuracy. The attached photoelectric sensor and the manufacturing method thereof can be provided.

  Hereinafter, a preferred embodiment of a photoelectric sensor and a manufacturing method thereof according to the present invention will be described in detail with reference to the accompanying drawings.

  A perspective view showing the external appearance of a reflective photoelectric sensor to which the present invention is applied is shown in FIG. As shown in the figure, the photoelectric sensor 1 is configured as a reflection type, and includes a case 10, an element / lens assembly 20 attached to the front-side opening of the case 10, and an upper surface of the case 10. The operation / display unit assembly 30 is mounted mainly on the side opening. In the figure, reference numeral 50a denotes an electrical cord, 21 denotes a lens plate on which a light projecting lens portion and a light receiving lens portion are formed, 23g and 23h denote mounting holes for installing the sensor, and 31a diffuses light from the indicator lamp. An illumination lens 31b is a rotary operator used for sensitivity adjustment and the like.

  An exploded perspective view showing the internal structure of the reflective photoelectric sensor is shown in FIG. As shown in the figure, the lens / element assembly 20 is formed by integrally coupling a lens plate 21 and a light projecting / receiving substrate 22 via a holder 23 made of synthetic resin. As will be described later with reference to FIG. 7, a light projecting lens portion 21 a and a light receiving lens portion 21 b are bulged on the back surface of the lens plate 21. On the light projecting / receiving substrate 22, a light projecting element 22a and a light receiving element 22b are mounted.

  The synthetic resin holder 23 is provided with two cavities 23e and 23f penetrating the holder in the front-rear direction. The lower cavity 23e is for the light projecting optical system, and the upper cavity 23f is for the light receiving optical system. On the side surface of the holder 23, two light shielding plate mounting slits 23i and 23j are formed in two upper and lower openings. As will be described later with reference to FIG. 3, a light projecting side light shielding plate 41 and a light receiving side light shielding plate 42 are inserted and fixed in these light shielding plate mounting slits 23i. Reference numerals 23g and 23h are mounting holes.

  Next, details of the operation / display unit assembly 30 will be described. The operation / display unit assembly 30 is configured by integrally connecting an operation / display block 31 and a circuit board 32. On the circuit board 32, a stability indicator lamp 32a and an operation indicator lamp 32b are mounted. On the other hand, on the surface of the operation / display block 31 mounted so as to cover the circuit board 32, an illumination lens 31a for diffusing the light from the stability indicator lamp 32a and the operation indicator lamp 32b to the outside, and sensitivity adjustment There are provided two operators 31b, 31c of a minus driver insertion type used for various operations such as. The protrusion 31e is for coupling the operation / display block 31 and the circuit board 32, and the protrusion 31d is engaged with the recess 10b on the case side when the operation / display block 31 is attached to the case 10. It is for stopping. Further, the convex portions 10 a provided on the inner surfaces facing each other of the case 10 are for coupling the case 10 and the holder 23. An electric cord assembly 50 is attached to the bottom of the case 10. In the figure, 50a is an electric cord and 50b is a cord holder.

  Next, a manufacturing method of the lens / element assembly 20 which is a main part of the present invention will be described in detail with reference to FIGS.

  FIG. 3 shows a perspective view of a reflection photoelectric sensor holder showing a light shielding plate mounting step. As described above, two light shielding plate mounting slits 23 i and 23 j are formed in the side surface of the holder 23. As shown in the drawing, the light projecting side light shielding plate 41 and the light receiving side light shielding plate 42 are respectively inserted into these light shielding plate mounting slits 23i and 23j as indicated by arrows. As will be described in detail later, the light shielding plates 41 and 42 are, for example, those obtained by depositing a chromium vapor deposition film on the surface of a glass plate, or metal plates having a thinned laser processing region. The size of the gap between the light shielding plate mounting slits 23i and 23j is substantially equal to the thickness of the light shielding plates 41 and 42. Therefore, the light shielding plates 41 and 42 are press-fitted and fixed to the slits 23i and 23j. In addition, after the press fitting is completed, the heat caulking convex portions 23k and 23l provided at the entrance portions of the respective slits are heated and crushed so that the light shielding plates 41 and 42 attached to the slits are securely removed. It is fixed. In the figure, reference numerals 23g and 23h denote mounting holes, 23c denotes a light projecting element housing part, and 23d denotes a light receiving element housing part.

  Next, FIG. 4 shows a side sectional view of the holder for the reflective photoelectric sensor after the light shielding plate is mounted and before the laser processing. As shown in the figure, in the holder 23, there are provided two hollow portions 23e and 23f that respectively penetrate the holder 23 in the front-rear direction. The lower cavity 23e is for the light projecting optical system, and a light projecting lens accommodating portion 23a is provided on the front side thereof, and a light projecting element accommodating portion 23c is provided on the rear side. That is, the cavity 23e communicates the light projecting lens housing 23a and the light projecting device housing 23c. Therefore, the light projecting side light shielding plate 41 is arranged so as to block the optical path from the light projecting element housing portion 23c to the light projecting lens housing portion 23a.

  A light receiving lens housing portion 23b is provided on the front side of the upper cavity portion 23f, and a light receiving element housing portion 23d is provided on the rear surface side. That is, the cavity 23f communicates the light receiving lens housing 23b and the light receiving device housing 23d. Therefore, the light receiving side light shielding plate 42 is disposed so as to block the optical path from the light receiving lens housing portion 23b to the light receiving element housing portion 23d.

  Next, FIG. 5 shows a side view of a holder for a reflective photoelectric sensor which is fixed to a jig and laser-processed. As shown in the figure, the holder 23 to which the light projecting side light shielding plate 41 and the light receiving side light shielding plate 42 are attached is fixed on an XYθ table of a laser processing machine (not shown) via a jig 60. In the example shown in the figure, the holder 23 is positioned and fixed on the XYθ table of the laser processing machine via the jig 60 while maintaining the horizontal posture with the lens housing portions 23a and 23b facing upward.

  When the laser processing machine is operated in this state, the laser beam emitted from the laser device irradiates the holder 23 from directly above. At this time, like the laser beam L1, the laser beam introduced from the light receiving lens housing 23b into the cavity 23f along the light receiving side optical axis is irradiated onto the light receiving side light shielding plate 42. At this time, if an XYθ stage (not shown) is appropriately moved and controlled, a light passage window having a predetermined shape is formed in the light receiving side light shielding plate 42. Here, as the predetermined shape, various shapes such as a slit (straight line) shape, a rectangular shape, a circular shape, an elliptical shape, and a semicircular shape can be realized by movement control of the XYθ stage. Moreover, since the processing accuracy in this type of laser processing machine is generally higher than the processing accuracy by the mold design, the light passage window can be formed with higher accuracy than before. Similarly, as shown by the laser beam L2, the laser beam introduced from the light projecting lens housing portion 23a into the cavity 23e along the light projecting side optical axis is irradiated onto the light projecting side light shielding plate 41. . At this time, if the XYθ stage is appropriately moved and controlled in the same manner as described above, a light passage window having a predetermined shape can be formed on the light projecting side light shielding plate 41.

  Next, FIG. 6 shows a side sectional view of the holder for the reflective photoelectric sensor after the light passage window is formed. In this example, as is apparent from the figure, the light passage window 41a is formed in the light shielding plate 41, and the light passage window 42a is formed in the light shielding plate 42, respectively. The cross-sectional structure of the light shielding plates 41 and 42 shown in the figure may be various variations such as a glass plate with a chromium vapor deposition film deposited thereon or a metal plate with a slightly thinned laser processing region.

  Next, FIG. 7 shows a side sectional view of the lens / element assembly 20 which is a holder for the reflection type photoelectric sensor in which the assembly of the light projecting / receiving element and the lens plate is completed. As is apparent from the drawing, in this state, the lens plate 21 is mounted on the front side of the holder 23 and the light projecting / receiving substrate 22 is mounted on the rear side. As described above, the light projecting lens portion 21a and the light receiving lens portion 21b are bulged on the back side of the lens plate 21. Therefore, the light projecting lens housing portion 23a located on the front side of the cavity 23e accommodates the light projecting lens portion 21a, and the light receiving lens housing portion 23b located on the front side of the cavity 23f accommodates the light receiving lens 21b. The As a coupling means between the lens plate 21 and the holder 23, for example, a press-fitting structure using a pin and a hole, an adhesive structure, or the like is employed. On the other hand, a light projecting element 22 a and a light receiving element 22 b are mounted on the light projecting / receiving substrate 22. The light projecting element 22a is accommodated in the light projecting element accommodating portion 23c, and the light receiving element 22b is accommodated in the light receiving element accommodating portion 23d. It should be noted that a press-fitting structure, a bonding structure, or the like using pins and holes is also used as a coupling means between the light projecting / receiving substrate 22 and the holder 23.

  According to the lens / element assembly 20 thus manufactured, the light projecting optical system and the light receiving optical system are configured in two upper and lower stages. The light projecting optical system located at the lower stage has a structure in which a light projecting side light-shielding plate 41 having a light projecting element 22a and a light passage window 41a, and a light projecting lens portion 21a are arranged in order, and emits light from the light projecting element 22a. After the beam cross-section is shaped by the light passage window 41a, the emitted light is condensed through the light projecting lens unit 21a and irradiated onto the detection target. That is, the light projection area is appropriately limited by the presence of the light passage window 41a. On the other hand, the light receiving optical system located in the upper stage is configured by sequentially arranging a light receiving lens portion 21b, a light passage window 42a, and a light receiving element 22b. Then, the light reflected by the detection target is converged by the light receiving lens portion 21b, and after the beam cross section is shaped by the light passage window 42a, it is irradiated to the light receiving element 22b. Thereby, the area of the light irradiated to the light receiving element 22b is limited by the light passing window 42a of the light receiving side light shielding plate 42, and the possibility that unnecessary disturbance light or the like is introduced into the light receiving element 22b can be eliminated.

  In addition, in this example, since the holder 23 and the light shielding plates 41 and 42 are separate parts, the light shielding plates 41 and 42 can be selectively mounted while the common holder 23 is used. Both customers who require a passage window and customers who do not require it can be handled. Moreover, since it can process the light passage window of arbitrary shape and a magnitude | size with respect to the customer who requests | requires a light passage window, it can respond to customer's arbitrary needs. In addition, since the holder 23 and the light shielding plates 41 and 42 can be made of different materials, the processing accuracy of the light passage windows 41a and 42a can be improved by making the material of the light shielding plates 41 and 42 easy to laser process. Can be improved.

  Next, another example of the manufacturing method of the lens / element assembly 20 will be described in detail with reference to FIGS.

  FIG. 13 shows a sectional side view of the holder for the reflective photoelectric sensor in a state where the light shielding plate is not mounted. Further, FIG. 14 shows a side sectional view of the holder for the reflective photoelectric sensor after mounting the light shielding plate and before laser processing. The reflection type photoelectric sensor holder shown in FIGS. 13 to 18 is shown except that the light receiving side light blocking plate 42 is provided non-parallel (inclined) to the light receiving lens portion 21b and the light receiving element 22b. The light receiving side light blocking plate 42 is arranged so as to block the optical path from the light receiving element housing portion 23d to the light receiving lens housing portion 23b, which is basically the same configuration as the reflection type photoelectric sensor holder shown in FIGS. .

  Next, FIG. 15 shows a side sectional view of the holder for the reflection type photoelectric sensor in which the inclination angle of the light shielding plate is calculated. FIG. 15 shows another example of the holder for the reflection type photoelectric sensor that is fixed to the jig and subjected to laser processing. An example of each is shown in FIG. FIG. 19 shows a flowchart showing a process of laser processing the light passage window on the light shielding plate in the inclined state. After the light emitting side light shielding plate 41 and the light receiving side light shielding plate 42 are attached to the light emitting side light shielding plate mounting portion 43 and the light receiving side light shielding plate mounting portion 44 of the holder 23, a laser processing machine (not shown) is connected via a jig 60. Fixed on the XYθ stage. In the example shown in the figure, the holder 23 is fixed in a state where the lens housing portions 23a and 23b are faced downward, and then the origin mark is read and X and Y machining origin correction is performed (steps). 2001). After correcting the processing origin, two points on the surface of the light-receiving side light-shielding plate 42 are focused, the positional information of the two points is stored (step 2002, step 2003), and two points based on the coordinates of the two focused points The amount of X and Y movement between them and the inclination φ in the Z direction are calculated, and the Z position is calculated from the X and Y information of the laser processing position (step 2004, step 2005). When the laser emitting lens focus is adjusted in accordance with the Z position information and the laser processing machine is operated, the laser beam L4 emitted from the laser device irradiates the holder 23 from the light shielding plate mounting portion side to perform laser processing (step) 2006, step 2007). At this time, if an XYθ stage (not shown) is appropriately moved and controlled, a light passage window having a predetermined shape is formed on the light-receiving side light-shielding plate 42. Here, as the predetermined shape, various shapes such as a slit (straight line) shape, a rectangular shape, a circular shape, an elliptical shape, and a semicircular shape can be realized by movement control of the XYθ stage.

  Next, FIG. 17 shows a side sectional view of the reflection type photoelectric sensor holder after the light passage window is formed. In this example, the light passing windows 41b and 42b formed by laser processing in the previous step are formed in the light projecting side light shielding plate 41 and the light receiving side light shielding plate 42, respectively.

  Next, FIG. 18 shows a side sectional view of another example of a lens / element assembly 20 that is a holder for a reflective photoelectric sensor in which the assembly of the light projecting / receiving element and the lens plate is completed. A major difference from the reflective photoelectric sensor holder shown in FIG. 7 is that the light-receiving side light-shielding plate 42 is held in an inclined state. FIG. 20 shows a comparison between the light receiving curve when the light receiving side light shielding plate is held in an inclined state and the light receiving curve when held in a parallel state. As is clear from the figure, the light receiving sensitivity in the required detection range is almost the same for any light shielding plate, but the light receiving sensitivity outside the detection range is better for the light shielding plate held in an inclined state. It can be seen that the light shielding plate which is extremely low and held in an inclined state is excellent in distance limitation. That is, it is possible to manufacture a reflective photoelectric sensor with a high distance limiting property that provides a steep light receiving characteristic in which the amount of received light decreases rapidly outside the detection range.

  Next, FIG. 8 shows a cross-sectional view of a transmissive photoelectric sensor holder showing a step of forming a slit by laser processing on a light shielding plate by integral molding. As shown in the figure, in this example, the light shielding plate 71d is integrally formed when the holder 71 is manufactured (injection molding). That is, in the hollow portion 71c that communicates the light projecting lens housing portion 71a and the light projecting element housing portion 71b, the light shielding plate portion 71d is integrally formed at the time of injection molding of the holder 71 so as to block this. The thickness of the light shielding plate 71d is appropriately selected so that a through hole can be formed by irradiation with the laser beam L3. That is, in this example, the holder 71 and the light shielding plate 71d are integrally formed in the injection molding process.

  In such a configuration, in the same manner as described above with reference to FIG. 5, after being fixed on the XYθ stage of the laser processing machine via the jig 80, the movement of the stage is controlled while irradiating the laser beam L3. In this way, a light passage window having a predetermined shape can be formed in the light shielding plate 71d.

  Next, FIG. 9 shows a cross-sectional view of an assembly of a transmissive photoelectric sensor holder in which a slit is formed by laser processing on an integrally formed light shielding plate. As shown in the figure, a lens plate 72 is mounted on the front side of the holder 71 and a light projecting substrate 73 is mounted on the rear side. A projection lens portion 72a is formed to bulge on the rear surface side of the lens plate 72, and the projection lens portion 72a is accommodated in the projection lens accommodation portion 71a. On the other hand, a light projecting element 73a is mounted on the light projecting substrate 73, and this light projecting element 73a is accommodated in a light projecting element accommodating portion 71b of a holder. The light projecting lens housing portion 71a and the light projecting element housing portion 71b communicate with each other via a hollow portion 71c, and a light shielding plate portion 71d having a light passage window 71g is provided in the hollow portion 71c.

  Therefore, the light emitted from the light projecting element 73a is appropriately shaped by the light passage window 71g, then condensed by the light projecting lens unit 72a, and projected onto the detection target region.

  According to such a lens / element assembly 70, two types of molding dies, that is, a molding die having a light shielding plate portion 71d and a molding die having no light shielding plate portion 71d are prepared, and a holder having a light shielding plate portion 71d in advance. If two types of holders that do not have are prepared, the shape of the light passage window 71g can be arbitrarily set by the action of the laser processing machine. Therefore, the lens / element assembly 70 having light passage windows having various shapes. Can be manufactured at low cost.

  Next, an explanatory view showing a variation of the slit forming method by laser processing is shown in FIG. In FIG. 6A, a resin shading plate is drilled by a laser processing machine, and the through hole 81a is formed by performing laser processing on the synthetic resin thin plate 81. Is formed. This method is suitable for the light shielding plate portion 71d by integral molding described above with reference to FIGS. That is, at the time of injection molding of the holder 71, the light shielding plate 71d is also formed at the same time, and a through hole is formed by irradiating this with a laser beam.

  In FIG. 4B, a light passage window is formed by laser processing on a thin metal plate. In this example, a light shielding plate formed by forming an electroformed metal layer 83 on the surface of the metal thin plate 82 is prepared, and the thin region 84 is irradiated with a laser beam to form a through hole 84a. Thus, an opening is formed for the light passage window. The electroformed metal layer 83 is for reinforcement and to maintain rigidity when press-fitted into the light shielding plate mounting slits 23i and 23j. The thickness of the thin metal plate 82 is preferably about 10 μm to 0.2 mm, and the thickness of the electroformed metal layer 83 is preferably about 0.5 mm to 2.0 mm.

  The one shown in FIG. 2C is intended to form an opening for a light passage window by performing laser processing on a metal vapor deposition film. In this example, a chromium deposition film 86 is formed on the surface of the glass plate 85, and a laser beam is irradiated on the chromium deposition film 86 to form a chromium removal region 86a. To do. In this example, since the chromium vapor deposition film 86 is sublimated and removed by irradiation with a laser beam, it is easy to form a light passage window, and if a glass plate 85 including an optical multilayer film is employed, By providing the glass plate 85 with an optical filter function, there is an advantage that it is not necessary to separately provide an optical filter plate. In addition, as a raw material of a glass plate, BK7, B270, etc. are preferable, and the thickness is preferably about 0.5 mm to 2.0 mm.

  As described above, by appropriately selecting the method shown in FIGS. 5A to 5C, a light passage window having an arbitrary shape can be formed with high accuracy on the light shielding plate.

  In FIGS. 4A to 4C, the light passage window is a laser for (a) synthetic resin thin plate 81, (b) metal thin plate 82, (c) chromium vapor deposition film 86, and thin plate or thin film. Since it is formed by processing, an opening equivalent to a knife edge shape can be obtained.

  Next, a system configuration diagram of the laser processing equipment is shown in FIG. As shown in the figure, the laser processing machine 90 includes an arithmetic processing device 91, a laser processing device 92, and a visual recognition device 93. The arithmetic processing unit 91 includes CAD data 91a and a laser / work control numerical arithmetic unit 91b. The laser processing device 92 includes a laser device 92a, a power supply device 92b, a cooling device 92c, a mirror 92d, a condenser lens 92e, and an XYθ stage device. Here, the XYθ stage apparatus includes an X direction stage 92f, a Y direction stage 92g, and a θ direction stage 92h. These stages 92f to 92h are capable of positioning control on the horizontal reference plane in each of the X direction, the Y direction, and the rotation direction (θ direction) about the vertical axis. Then, the workpiece W is placed on the θ-direction stage 92h. Here, as the work W, in the present invention, the holder 23 or 71 made of synthetic resin corresponds to this.

  On the other hand, the visual recognition device 93 includes an illumination light source 93a, a half mirror 93b, and a camera 93c incorporating a CCD or the like.

  In the above configuration, when the laser processing machine 90 starts operating, the laser / work control numerical arithmetic unit 91b appropriately controls the X direction stage 92f, the Y direction stage 92g, and the θ direction stage 92h according to the CAD data 91a. Then, the movement of the work W is appropriately controlled. At this time, the position of the workpiece W is controlled based on information from the camera 93c. On the other hand, the laser light emitted from the laser device 92a is reflected vertically below by the mirror 92d, then condensed by the condenser lens 92e, and irradiated onto the surface of the workpiece W. Accordingly, as described above with reference to FIGS. 5 and 8, the light passage windows 41a, 42a, and 71g are formed in the light shielding plates 41 and 42 or the light shielding plate portion 71d.

  A flowchart showing the software configuration of the arithmetic processing unit 91 is shown in FIG. As shown in the figure, when the work is set, the operation of the apparatus is started by waiting for the start switch to be turned on or by the auto-start function (step 101), and then the CAD data is read (step 101). Step 102). Thereafter, after the XYθ stage device is returned to the origin position (step 103), the movement to the machining position (step 104) and the laser machining (step 105) are repeatedly executed. Then, after waiting for the machining process scheduled in advance according to the CAD data to be completed, the workpiece is taken out (step 106), the process for one holder is completed, and thereafter the same process is repeated, so that one product can be manufactured. In addition, it is possible to form an opening for a light passage window in this type of photoelectric sensor.

  According to the embodiment described above, since the light passage window such as a slit is formed in the holder by using laser processing technology, the shape of the light passage window can be any of round holes, square holes, irregular shapes, etc. In addition, it is possible to adopt a different shape of the light passage window by forming different light passage windows on the holder in a later process. Can be reduced.

  Moreover, since the light shielding plate is laser processed to produce a product having a light passage window of an arbitrary shape and size, the number of types of the light shielding plate material and the holder without the light shielding plate is reduced, and as a result, the production amount is reduced. Therefore, there is an advantage that the cost of the light shielding plate material and the holder without the light shielding plate is reduced due to the mass production effect, leading to cost reduction of the photoelectric sensor itself.

  Moreover, the position accuracy of the light passage window is improved by processing the light passage window directly on the holder. Specifically, the position accuracy when determining the size and shape of the light passage window by the conventional mold design was about ± 0.05 mm, but the light passage window was directly formed by the laser processing of the present invention. The positional accuracy in forming the opening could be ± 0.03 mm or less.

  Moreover, since the positional relationship between the light projecting / receiving element and the lens can be accurately constructed by post-processing the light passage window, an advantage that the optical performance is improved was also confirmed.

  Further, since the light passage window is formed by laser processing on a thin plate or thin film, an opening equivalent to a knife edge shape can be obtained.

  Further, the light passage window can be processed by the laser processing of the present invention even for the light shielding plate held in an inclined state. A reflective photoelectric sensor having a light-shielding plate held in an inclined state has an advantage that a steep light-receiving characteristic in which the amount of received light is drastically reduced outside the detection range can be obtained, and distance limitation is enhanced.

  Furthermore, in the example of making the light shielding plate by depositing a chromium vapor deposition film or the like on the surface of the glass, if the glass plate itself is an optical bandpass filter, it exceeds the function of a simple light passage window, Since the window itself has various optical characteristics, there is an advantage that a new technical development can be expected.

It is a perspective view which shows the external appearance of the reflection type photoelectric sensor to which this invention was applied. It is a disassembled perspective view which shows the internal structure of the reflection type photoelectric sensor to which this invention was applied. It is a perspective view of the holder for reflection type photoelectric sensors which shows a shading board mounting process. It is the sectional side view (the 1) of the holder for reflection type photoelectric sensors after laser-shielding board mounting | wearing and before laser processing. It is the sectional side view (the 1) of the holder for reflection type photoelectric sensors currently fixed to the jig | tool and performing the laser processing. It is a sectional side view (the 1) of the holder for reflection type photoelectric sensors after light passage window formation. It is a sectional side view (the 1) of the holder for reflection type photoelectric sensors in which the assembly of the light emitting / receiving element and the lens plate is completed. It is sectional drawing of the holder for transmissive | pervious photoelectric sensors which shows the process of forming a light passage window by laser processing in the light-shielding plate by integral molding. It is sectional drawing which shows the assembly of the holder for transmission type photoelectric sensors which formed the light passage window in the light-shielding plate by integral molding by laser processing. It is explanatory drawing which shows the variation of the light passage window formation method by laser processing. It is a system configuration figure of laser processing equipment. It is a flowchart which shows the software structure of an arithmetic processing unit. It is a sectional side view of the holder for reflection type photoelectric sensors in the state where a light-shielding plate is not attached. It is a sectional side view (the 2) of the holder for reflection type photoelectric sensors after laser-shielding board mounting | wearing and before laser processing. It is a sectional side view of the holder for reflective photoelectric sensors in which the inclination angle of the light shielding plate is calculated. It is a sectional side view (the 2) of the holder for reflective photoelectric sensors currently fixed to the jig | tool and performing the laser processing. It is a sectional side view (the 2) of the holder for reflection type photoelectric sensors after light passage window formation. It is a sectional side view (the 2) of the holder for reflection type photoelectric sensors which the assembly | attachment of the light projection / reception element and the lens member was completed. It is a flowchart which shows the process of processing a light passage window with a laser beam in the light-shielding plate of an inclined state. It is a figure which shows the comparison with the light reception curve when the light-receiving side light-shielding plate is hold | maintained in the inclination state, and the light reception curve when it hold | maintains in a parallel state.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Reflection type photoelectric sensor 10 Case 10a Convex part 10b Concave part 20 Lens / element assembly 21 Lens plate 21a Light projection lens part 21b Light reception lens part 22 Light projection / reception board 22a Light projection element 22b Light reception element 23 Holder 23a Light projection lens accommodating part 23b Light receiving lens accommodating portion 23c Light projecting element accommodating portion 23d Light receiving element accommodating portion 23e, 23f Cavity portion 23g, 23h Mounting hole 23i, 23j Light shielding plate mounting slit 23k, 23l Heat caulking convex portion 30 Operation / display unit assembly 31 Operation / display Display block 32 Circuit board 31a Illuminating lens 31b, 31c Operating element 32a Stability indicator lamp 32b Operation indicator lamp 31d, 31e Convex part 41 Projection side light shielding plate 41a, 41b Light passage window 42 Light reception side light shielding plate 42a, 42b Light passage window 43 Light emitting side light shielding plate accommodating portion 44 Light receiving side light shielding plate accommodating portion 50 Code cord assembly 50a Electric cord 50b Cord holder 60 Jig 70 Lens / element assembly 71 Holder 71a Light projection lens housing portion 71b Light projection device housing portion 71c Cavity portion 71d Light shielding plate portion 71e, 71f Mounting hole 71g Light passage window 72 Lens plate 72a Projection lens part 73 Projection substrate 73a Projection element 80 Jig 81 Synthetic resin thin plate 81a Through hole 82 Metal thin plate 83 Electroformed metal layer 84 Thin wall region 84a Through hole 85 Glass plate 86 Chrome vapor deposition film 86a Chrome Removal area 90 Laser processing machine 91 Arithmetic processing unit 91a CAD data 91b Laser / work control numerical calculation unit 92 Laser processing unit 92a Laser unit 92b Power supply unit 92c Cooling unit 92d Mirror 92e Condensing lens 92f X direction stage 92g Y direction stage 92h θ Direction Over di 93 visual recognition device 93a light source 93b half mirror 93c Camera W workpiece φ inclination L1, L2, L3, L4 laser beam

Claims (8)

A synthetic resin holder having a light projecting element housing portion, a light projecting lens housing portion, a cavity connecting them, and a light shielding plate portion that is in the cavity and blocks an optical path from the light projecting element to the light projecting lens is emitted. A first step of integrally molding by molding;
After the synthetic resin holder obtained in the first step is mounted on the laser processing machine with a predetermined jig, the light projecting element housing part side or the light projecting lens housing part side enters the cavity along the light projecting optical axis. A second step of opening a light passage window by introducing a laser beam and perforating the light shielding plate portion into a predetermined shape;
Including a third step of completing the element / lens assembly by mounting the light projecting element and the light projecting lens on the synthetic resin holder in which the light passage window is formed in the light shielding plate by the second step.
A method for manufacturing a photoelectric sensor. A light projecting element accommodating portion, a light projecting lens accommodating portion, a cavity connecting them, and a light shielding plate accommodating portion for mounting a light shielding plate in the cavity that blocks the optical path from the light projecting element toward the light projecting lens; A first step of integrally molding a synthetic resin holder having injection molding by injection molding;
A second step of mounting the light shielding plate on the light shielding plate housing portion in the synthetic resin holder obtained by the first step;
After mounting the synthetic resin holder with the light shielding plate obtained in the second step on the laser processing machine with a predetermined jig, the light projecting element housing part side or the light projecting lens housing part side into the light projecting optical axis in the cavity part A third step of opening a light passage window by introducing a laser beam along and laser processing the light shielding plate into a predetermined shape;
And a fourth step of completing the element / lens assembly by mounting the light projecting element and the light projecting lens on the synthetic resin holder in which the light passage window is formed in the light shielding plate by the third step.
A method for manufacturing a photoelectric sensor. Synthetic resin holder having a light receiving lens housing portion, a light receiving device housing portion, a cavity connecting them, and a light shielding plate portion in the cavity that blocks the optical path from the light receiving lens to the light receiving device is integrally formed by injection molding. A first step to:
After the synthetic resin holder obtained in the first step is mounted on the laser processing machine with a predetermined jig, a laser beam is emitted along the light receiving optical axis from the light receiving lens housing part side or the light receiving element housing part side into the cavity. A second step of opening and forming a light passage window by introducing and punching the light shielding plate part into a predetermined shape;
And a third step of completing the element / lens assembly by mounting the light receiving element and the light receiving lens on the synthetic resin holder in which the light passage window is formed in the light shielding plate portion by the second step.
A method for manufacturing a photoelectric sensor. The method for manufacturing a photoelectric sensor according to claim 3 , wherein the light shielding plate portion is installed with a light receiving element housing portion and a light receiving lens housing portion with a predetermined inclination. Synthetic resin having a light receiving element accommodating portion, a light receiving lens accommodating portion, a cavity connecting them, and a light shielding plate accommodating portion for mounting a light shielding plate that is in the cavity and blocks an optical path from the light receiving lens toward the light receiving element A first step of integrally molding the holder made by injection molding;
A second step of mounting the light shielding plate on the light shielding plate housing portion in the synthetic resin holder obtained by the first step;
After the synthetic resin holder with the light shielding plate obtained in the second step is mounted on the laser processing machine with a predetermined jig, the laser is moved along the light receiving optical axis from the light receiving lens housing part side or the light receiving element housing part side into the cavity. A third step of opening the light passage window by introducing a beam and laser processing the light shielding plate into a predetermined shape;
And a fourth step of completing the element / lens assembly by mounting the light receiving lens and the light receiving element on the synthetic resin holder in which the light passage window is formed in the light shielding plate by the third step.
A method for manufacturing a photoelectric sensor. The method for manufacturing a photoelectric sensor according to claim 5 , wherein the light shielding plate accommodating portion is provided with a light receiving plate accommodating portion and a light receiving lens accommodating portion with a predetermined inclination. 4. The method of manufacturing a photoelectric sensor according to claim 3 , wherein the second step includes a step of performing laser processing after calculating an inclination angle of the light shielding plate based on coordinates of two points on the light shielding plate. 6. The method of manufacturing a photoelectric sensor according to claim 5 , wherein the third step includes a step of performing laser processing after calculating an inclination angle of the light shielding plate based on coordinates of two points on the light shielding plate.

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