JP3914527B2 - Light irradiation device - Google Patents

Description

  The present invention relates to a light irradiation apparatus that irradiates a product with light supplied via an optical fiber and inspects the appearance and scratches of the product, or detects an alignment mark.

  2. Description of the Related Art Conventionally, as disclosed in Patent Document 1, a light irradiation device that illuminates a workpiece by irradiating light supplied from a light source device such as a halogen lamp via a plurality of optical fibers is known. Since such a light irradiation apparatus does not incorporate a light source, it is easy to reduce the size and weight, and can contribute to an improvement in installation flexibility.

On the other hand, as the work to be inspected, there is an increasing demand for precise inspection by performing bright illumination on extremely small parts such as semiconductor chips and soldered parts of the semiconductor chips to the printed circuit board. Therefore, it is necessary to collect the irradiation light more efficiently and to irradiate the irradiation target site with the brighter light more efficiently.
JP-A-5-248820

  However, from this point of view, this type of conventional light irradiation device is insufficient in terms of light collection area, light collection efficiency, and the like. For example, in the light irradiation device disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 5-199442, although it is possible to prevent light from escaping to the outside by the ring lens, only the radial condensing of the ring lens is performed and Since no light is collected, sufficient light cannot be collected on a small area.

  On the other hand, in the case where light is collected by attaching lenses to each optical fiber one by one, it is necessary to make the positional relationship between the light exit end of each optical fiber and the lens uniform. This is because if this is not uniform, the light collection is not suitably performed, and there is a possibility that the illuminance of the irradiation target portion may be uneven. However, when there are a large number of optical fibers, it becomes difficult to set the positional relationship between each fiber and the lens uniformly.

  Therefore, the present invention can determine the positional relationship between the light exit end of the optical fiber and the lens very easily and accurately, and can also improve the light transmission efficiency between them as much as possible. The main objective is to provide an apparatus and solve the above-mentioned problems all at once.

That is, the light irradiation apparatus according to the present invention includes a fiber holding portion having a fiber insertion hole for holding a light emission end portion of an optical fiber, and a lens holding portion provided on the light traveling direction side of the fiber holding portion. And irradiates the irradiation target site with the light emitted from the light exit end of the optical fiber via the lens held by the lens holding portion, and the fiber insertion hole is substantially the same as the optical fiber. The same-diameter portion having the same diameter and a large-diameter portion having a larger diameter than the same-diameter portion and opening at one end surface of the fiber holding portion, and holding the optical fiber through the same-diameter portion. together, the melted portion of the distal end portion is formed by melting the deformation of the optical fiber projecting from its constant diameter portion is fitted in the large diameter portion, in Rukoto is brought into contact with the lens on the tip surface of the molten portion, The optical fiber in the direction of light travel Respect is included forces the lens against, that their said large-diameter portion to compete against opposing pulling force, characterized in that there as a structure for holding the optical fiber.

  Here, the “one end face of the fiber holding portion” means an end face on the light traveling direction side, and includes the open end of the large diameter portion.

In such a case, the melted portion is formed continuously with the light emitting end of the optical fiber, and the melted portion has a fixed shape that fits into the large diameter portion. It is possible to accurately and easily determine the distance between the injection end and the lens in contact with the tip surface of the melting portion. Therefore, for example, when a plurality of optical fibers are arranged in an annular shape to illuminate a predetermined irradiation target site from the surroundings, the light emitted from each optical fiber can be condensed uniformly and at the same position. Condensing light onto the target site can be suitably performed without difficulty.

  Further, the end surface of the melted portion can be made into a mirror surface state without any polishing treatment or the like, and light transmission in that portion is not hindered, so that the end surface polishing treatment step can be omitted.

  Furthermore, if the lens is configured to abut on the distal end surface of the melted portion, the lens opposes the pushing force of the optical fiber in the light traveling direction, and the pulling force in the opposite direction is large. Since the diameter portion opposes, the optical fiber can be securely held without being bonded to the fiber insertion hole.

  In order not to affect the transmission efficiency of the irradiation light, the shape of the large diameter portion is set so that the light emitted from the light emission end does not hit the inner surface of the large diameter portion. What you are doing is desirable.

  As a specific embodiment for facilitating assembly, the lens holding portion includes a lens holding hole for receiving and holding a lens, and the fiber holding portion has the same cross-sectional shape as the lens holding hole. It is made into a columnar shape that penetrates the fiber insertion hole in the axial direction, and is fitted to the anti-irradiation target site side of the lens holding hole into which the lens is inserted to open the front end surface of the melting part or the opening of the large diameter part The thing which makes the said lens contact | abut to an edge part can be mentioned.

  When a lens having a large diameter is used, the diameter of the lens holding hole for holding the lens is naturally increased. However, changing the shape of the fiber holding portion that requires relatively precise processing and the fiber must be inserted in accordance with the lens holding hole is a burden on the manufacturing equipment and also from the viewpoint of cost, etc. It is not preferable. Therefore, in order to support various lens holding holes while using a standardized fiber holding part, the fiber holding part has a smaller diameter than the lens holding hole, It is preferable to further include a cylindrical adapter that fits the fiber holding portion without rattling and the outer periphery of the fiber holding portion fits into the lens holding hole.

  In this case, if a tapered surface for contacting and fixing the lens is formed on the irradiation target site side of the adapter, the lens can be stably held, so that it is even better.

  As a specific embodiment in which the effect of the present invention is particularly remarkable, a housing having an observation hole for observing the irradiation target site is provided, and is provided at an opening peripheral portion of the observation hole. A plurality of fiber insertion holes for holding the optical fibers are provided intermittently at equal intervals, and the lens holding unit is configured to hold the lenses corresponding to each optical fiber one by one. be able to.

  In that case, in order to collect light more effectively, a single unit is formed so as to form an annular shape by providing a through-hole that is positioned between the lens and the irradiation target site and is coaxial with the observation hole. The second lens may be further provided, and the second lens may be configured to refract the irradiation light emitted from each lens and collect it at the irradiation target site.

  As a specific embodiment of the lens holding portion, there can be mentioned one having an annular shape and a plurality of lens holding holes provided at equal intervals along the circumferential direction.

  A lens having a spherical shape is preferable in that the configuration of the lens holding portion can be simplified.

  Further, the melting part is not necessarily required, and the basic function and effect of the present invention can be achieved as long as the distance between the light emitting end of the optical fiber and the lens can be secured accurately and easily. Specifically, the fiber insertion hole is composed of the same diameter portion having substantially the same diameter as the optical fiber, and a large diameter portion having a larger diameter than the same diameter portion and opening at one end surface of the fiber holding portion. It is conceivable that the optical fiber is passed through the same-diameter portion and the light emission end thereof is held in alignment with the tip of the same-diameter portion and the lens is brought into contact with one end surface of the fiber holding portion.

  An embodiment of the present invention will be described below with reference to the drawings.

  The light irradiation apparatus X6A according to the present embodiment is used as a component of a product inspection system as shown in FIG.

  This product inspection system will be briefly described. This system uses an XY stage X1 which is a movable support body that can move horizontally in two horizontal directions, that is, the X-axis direction and the Y-axis direction. A photoconductive tube X2 supported by the stage X1, an imaging device X8 for photographing the irradiation target portion XW of the workpiece via the photoconductive tube X2, and a power source X3 installed at a location different from the XY stage X1 And LED light source devices X5A and X5B supplied with power from the power source X3 via a robot cable X4, and a slidably attached to the lower end portion of the photoconductive tube X2, and light from the periphery of the irradiation target site XW ( Light irradiation device X6A for illuminating with side illumination) and the irradiation pair via an optical member attached to the upper end of the light conducting tube X21 and provided therein. A second light irradiating device X6B for illuminating with light (epi-illuminated light) from above the part XW, and a light guide resin that guides light from the LED light source devices X5A, X5B to the light irradiating devices X6A, X6B And optical fiber bundles X7A and X7B.

  Then, when a workpiece such as a printed circuit board is conveyed by a conveyance device (not shown), for example, the alignment mark of the workpiece is taken from the imaging device X8 and is recognized by an image recognition unit (not shown), and the position information of the alignment mark is calculated. At the same time, the XY stage X1 is automatically controlled so that the photoconductive tube X2 is positioned immediately above the irradiation target site W of the workpiece based on the position information. As a result, the irradiation target portion XW is illuminated from the periphery and directly above by the light irradiated from the light irradiation devices X6A and X6B, and a suitable image that is accurate and free of shadows can be obtained by the imaging device X8. Since the position information of the workpiece can be obtained by controlling the position of the XY stage X1 in this way, the present system can be used as a workpiece position measuring system or used for barcode reading or the like. You can do it.

  Accordingly, the light irradiation device X6A according to the present embodiment is for supplying light from the LED light source device X5A via the optical fiber bundle X7A, and for illuminating the light by applying the light to the irradiation target portion XW from the periphery. , The outer diameter is about 10 mm to 30 mm. This light irradiation device X6A is attached to the end of the light conducting tube X2 on the irradiation target site side, that is, the lower end, and observes the irradiation target site XW as shown in FIGS. A cylindrical casing X6A1 having an observation hole X6H, a fiber bundle holding portion X6A2 that holds one end of the optical fiber bundle X7A, and a cover body X6A3 that covers the casing X6A1 from the outside. Become.

  More specifically, the casing X6A1 has a cylindrical shape and the inner periphery of the casing X6A11 is the observation hole X6H. The casing X6A1 is externally fitted to the casing main body X6A11, and the periphery of the opening of the observation hole X6H, that is, irradiation. A ring-shaped lens holding portion X6A12 that protrudes outward from the end portion on the target site XW side in a bowl shape.

  A lens holding hole XHL set at a predetermined angle with the axis of the observation hole X6H so that the central axis XL passes through the center point of the irradiation target site XW is formed in the bowl-shaped portion of the lens holding part X6A12. A plurality are provided at equal intervals along the circumferential direction.

  As shown in an enlarged view in FIG. 4, the lens holding hole XHL has a circular cross section, and the inner diameter thereof is the same as or substantially the same as the outer diameter of the ball lens X9 as a lens. Then, the ball lens X9 fitted from the side opposite to the irradiation target site is held at one end on the irradiation target site side. In the lens holding hole XHL, a small-diameter portion XHL1 having a slightly small diameter is provided at the one end portion on the irradiation target site XW side, and the ball lens X9 is held in the small-diameter portion XHL1 so as not to be pulled out to one end side. It functions as a ban. The opening on the irradiation target site XW side in each lens holding hole XHL is a light irradiation port X6Aa.

  On the other hand, a cylindrical fiber holding portion XB having the same diameter or substantially the same diameter as the inner diameter of the lens holding hole XHL is fitted by press fitting or the like so as to prevent the ball lens X9 from coming off upward. There is. The columnar member XB is a resin molded product such as polyacetal, for example, and is provided with a fiber insertion hole XB1 extending through the central axis. The optical fiber X7a is inserted and held in the fiber insertion hole XB1.

  The fiber insertion hole XB1 has a large-diameter portion XB11 formed, for example, in a conical shape from one end on the irradiation target site XW side, and an inner diameter set to be the same as or substantially the same as the outer diameter of the optical fiber X7a. The tip portion of the optical fiber X7a inserted from the same diameter portion XB12 toward the large diameter portion XB11 is melted by using a hot plate or the like, and the melting portion X7a1 is melted by the large diameter portion XB12. The portion XB11 is fitted with no gap. The substantial light exit end X7a2 of the optical fiber 7a having the core and the clad is configured to coincide with the tip of the same diameter portion XB12. The widening angle of the large diameter portion XB11 is set to be larger than or equal to the spreading angle of the light emitted from the light exit end X7a2.

  Here, a method of incorporating the optical fiber X7a and the ball lens X9 will be described with reference to FIGS.

  As shown in FIG. 5, first, the fiber holding portion XB is placed on the flat surface portion of the hot plate HP set to a predetermined temperature at which the optical fiber X7a is melted, with the end surface on the large diameter portion XB11 side in close contact (see FIG. 5). a). Here, the flat portion of the hot plate HP has a very smooth mirror surface. Next, the optical fiber X7a is inserted into the fiber insertion hole XB1 from the same-diameter portion XB12 side, and the tip of the optical fiber X7a passes through the same-diameter portion XB12 to reach the flat portion of the hot plate HP (b in FIG. 5). . As a result, the tip portion of the optical fiber X7a begins to melt by the heat from the hot plate HP, and the melted portion X7a1 becomes a uniform transparent resin having no boundary between the core and the clad (FIG. 3c). However, since the melting portion X7a1 expands so as to fill the large diameter portion XB11, the optical fiber X7a is further fed at a predetermined pressure for a predetermined time so as to correspond thereto.

  Accordingly, by appropriately setting the temperature of the hot plate HP, the feeding pressure of the optical fiber X7a, and the feeding time after the tip of the optical fiber X7a comes into contact with the hot plate HP, the melting part X7a becomes the large diameter part. It fills and fits without a gap, and its tip end surface is flush with one end surface on the irradiation target site XW side in the fiber holding portion XB, and the position of the light emitting end X7a2 of the optical fiber X7a is the melting portion. The distal end surface of X7a1 or the end portion of the fiber holding portion XB is a predetermined distance away, specifically, the distal end of the same diameter portion XB12 (boundary with the large diameter portion XB11).

  Next, as shown in FIG. 6, with each fiber holding portion XB holding the light emitting end portion of the optical fiber X7a, the fiber holding portion XB is fitted to the other end portion of the lens holding hole XHL as described above. The tip of the melting part X7a1 is brought into contact with the ball lens X9 (FIG. C).

  With such a configuration, the ball lenses X9 are arranged one by one on the light exit end face of each optical fiber X7a via the fusion part X7a1, and the axis at the light exit end of each optical fiber X7a and the light of the ball lens X9. The irradiation target part XW is illuminated from the surroundings by matching the axes and setting the optical axis of each irradiation light to be directed to a predetermined point of the irradiation target part XW. It should be noted that the optical axis of each irradiation light does not necessarily have to face one predetermined point of the irradiation target site XW, and may be distributed and directed in the region of the irradiation target site XW depending on the application.

  As shown in FIG. 2 and the like, the fiber bundle holding portion X6A2 is attached so as to protrude outward from the housing X6A1 and holds one end portion of the optical fiber bundle X7A as described above. Therefore, each optical fiber X7a maintains the form as a bundle up to the fiber bundle holding portion X6A2, and from here on, the individual optical fibers X7a hold the respective light emitting end portions in the respective fiber holding portions XB1. Is done. Note that a connector X71 is attached to the other end of the optical fiber bundle X7A so that irradiation light emitted from the LED light source device X5A can be introduced.

  The cover body X6A3 has a cylindrical shape, and is attached to the casing X6A1 so as to form a space XS with respect to the outer peripheral surface of the lower end portion of the casing X6A1. The respective optical fibers X7a are accommodated and protected in the space XS.

  Thus, according to the light irradiation apparatus X6A according to the present embodiment configured as described above, the melting portion X7a1 is formed continuously with the light emitting end X7a2 of the optical fiber X7a, and the melting portion X7a1 is formed in the large diameter portion XB11. Since it becomes what forms a fixed shape, it is possible to accurately and easily determine the distance between the light emitting end X7a2 of the optical fiber X7a and the lens X9 that abuts the tip end surface of the melting portion X7a1. Therefore, even if the plurality of optical fibers X7a are arranged in a ring shape, the light emitted from each optical fiber X7a can be uniformly condensed, and the light can be suitably condensed onto the irradiation target site XW without difficulty.

  Further, the tip surface of the melted part X7a1 is in a mirror-finished state without any polishing process or the like, so that light transmission in that part is not hindered, so that the end surface polishing process can be omitted.

  Further, since the lens X9 is configured to abut on the distal end surface of the melted part X7a1, the lens X9 opposes the pushing force of the optical fiber X7a in the light traveling direction, and the pulling force in the opposite direction is countered. On the other hand, since the large-diameter portion XB11 opposes, the optical fiber X7a can be securely held without being bonded to the fiber insertion hole XB.

  Further, since the expansion angle of the large diameter portion XB11 is set to be larger than or equal to the expansion angle of the light emitted from the light emitting end X7a2 of the optical fiber X7a, the light is emitted while expanding from the light emitting end. It is possible to prevent the emitted light from hitting the inner surface of the large-diameter portion XB11 and to affect the transmission efficiency of the irradiation light at that portion.

  In addition, since the optical fiber X7a is assembled into the fiber holding part XB, the fiber holding part XB is inserted into the lens holding hole XHL, so that the assembly can be divided and the manufacturing efficiency can be promoted. Since the fiber holding portion XB also serves to prevent the ball lens X9 from coming off, a dedicated retaining structure can be dispensed with and the structure can be simplified.

  In addition, this invention is not limited to the said Example. In the following description and drawings, the same reference numerals are assigned to members corresponding to the above-described embodiments.

  In FIG. 7, the optical axis of the lens X9 and the axis at the light exit end of the optical fiber X7a are set so as to deviate, whereby the optical axis of the irradiation light is bent through the lens X9, and the optical axis is the portion to be irradiated. It is a fragmentary sectional view of light irradiation apparatus X6 made to face XW. In this way, the axis at the light exit end of the optical fiber X7a does not necessarily have to be set to face the irradiation target site XW. Specifically, for example, the fiber insertion hole XHL may be formed in a portion displaced from the central axis of the fiber holding portion XB. In this case, the lens X9 does not necessarily abut on the end surface of the fusion part X7a1, and may abut on the end surface of the fiber holding part XB.

  Further, as shown in FIG. 8, in order to further collect the light from each lens X9, a single second condensing lens having an opening X75A formed at the center (in the figure, it is a Fresnel lens). Any lens such as a convex lens may be used). In this case, it is preferable that the lens X9 converts the light from the optical fiber X7a into parallel light in consideration of the condensing by the second lens X75.

  Furthermore, the melting part is not necessarily required, and the basic function and effect of the present invention can be achieved as long as the distance between the light emitting end of the optical fiber and the lens can be secured accurately and easily. For example, it is conceivable that the optical fiber is passed through the same-diameter portion and the light emission end thereof is held in alignment with the tip of the same-diameter portion and the lens is brought into contact with one end surface of the fiber holding portion. . Specifically, as shown in FIG. 9, a mode in which the lens X9 is brought into contact with the opening peripheral edge of the large diameter portion XB11 and a part of the lens X9 enters the large diameter portion XB11. Here, in order to make the light emission end X7a12 of the optical fiber X7a coincide with the tip of the same-diameter portion XB12, any jig may be used, and an adhesive or the like may be used to hold the optical fiber X7a.

  In addition, for example, the lens member insertion hole may have a cross section other than a circle, and the shape of the fiber holding portion may be changed correspondingly.

  In addition, as shown in FIG. 13, the ball lens X9 may be an annular lens that is formed by integrally connecting peripheral edges with a thin plate, for example, without forming a separate body for each. In this case, although the ball lens X9 is physically connected, it is functionally considered to have an independent function for each optical fiber. Of course, the lens is not limited to a spherical ball type, but any lens having a spherical shape may be inserted into the lens holding hole in any posture, and is suitable for assembly.

  In addition, the large diameter portion is not limited to a conical concave shape, and may be a cylindrical concave shape as shown in FIG. 10 or a partially concave spherical shape as shown in FIG. In short, it is preferable that the shape of the large-diameter portion is set so that the light emitted while spreading from the light exit end does not hit the inner surface of the large-diameter portion.

  Furthermore, when using a lens having a large diameter, the diameter of the lens holding hole for holding the lens naturally increases. However, changing the shape of the fiber holding portion that requires relatively precise processing and the fiber must be inserted in accordance with the lens holding hole is a burden on the manufacturing equipment and also from the viewpoint of cost, etc. It is not preferable.

  Therefore, as shown in FIG. 12, when the fiber holding portion XB has a smaller diameter than the lens holding hole XHL, the fiber holding portion XB is fitted to the inner periphery X10a without any problem, and the outer periphery X10b is You may make it provide further the adapter X10 which makes | forms the cylinder shape which fits in the lens holding hole XHL. The adapter X10 in this figure has a cylindrical shape, and a concave conical tapered surface X10c is formed on the irradiation target site side. This taper surface X10c abuts on and fixes the lens X9.

  1 is an overall perspective view of a light irradiation device according to an embodiment of the present invention.   The longitudinal cross-sectional view of one light irradiation apparatus in the embodiment.   The bottom view of one light irradiation apparatus in the embodiment.   The fragmentary sectional view of one light irradiation apparatus in the embodiment.   Assembly explanatory drawing which shows the assembly of the optical fiber in the embodiment.   Assembly explanatory drawing which shows the assembly of the optical fiber and lens in the embodiment.   The fragmentary longitudinal cross-section of the light irradiation apparatus in the modification of the embodiment.   The fragmentary longitudinal cross-section of the light irradiation apparatus in the other modification of the embodiment.   The fragmentary longitudinal cross-section of the light irradiation apparatus in the further another modification of the embodiment.   The fragmentary longitudinal cross-section of the light irradiation apparatus in the further another modification of the embodiment.   The fragmentary longitudinal cross-section of the light irradiation apparatus in the further another modification of the embodiment.   The fragmentary longitudinal cross-section of the light irradiation apparatus in the further another modification of the embodiment.   The top view (a) and center longitudinal cross-sectional view (b) of the lens in the further another modification of the embodiment.

Explanation of symbols

X7a ... Optical fiber X7a2 ... Light exit end XB1 ... Fiber insertion hole XB ... Fiber holder X6A12 ... Lens holder X9 ... Lens (ball lens)
XW ... Irradiation target site XB12 ... Same diameter part XB11 ... Large diameter part X7a1 ... Melting part XHL ... Lens holding hole X6H ... Observation hole X6A1 ... Housing X75 ... Second lens X10 ... Adapter

Claims (8)

A fiber holding portion having a fiber insertion hole for holding the light emission end portion of the optical fiber, and a lens holding portion provided on the light traveling direction side of the fiber holding portion, from the light emission end of the optical fiber The emitted light is irradiated to the irradiation target site through the lens held by the lens holding unit,
A small-diameter portion that holds the lens so that the lens does not come out to one end side is provided at one end of the lens holding hole provided in the lens holding portion on the irradiation target site side.
The fiber insertion hole is composed of a same-diameter portion that has substantially the same diameter as the optical fiber, and a large-diameter portion that has a larger diameter than the same-diameter portion and opens at one end surface of the fiber holding portion. The optical fiber is passed through and held, and the melted part formed by melting and deforming the tip of the optical fiber protruding from the same diameter part is fitted to the large diameter part,
The fiber holding portion has a columnar shape that has the same diameter or substantially the same diameter as the inner diameter of the lens holding hole and penetrates the fiber insertion hole in the axial direction, and the anti-irradiation target portion of the lens holding hole into which the lens is inserted The lens is brought into contact with the front end surface of the melted portion and the lens opposes the pushing force in the light traveling direction of the optical fiber, and the opposite pulling force The light irradiation apparatus is characterized in that the optical fiber is held by the large-diameter portion facing.   The light irradiation apparatus according to claim 1, wherein the shape of the large-diameter portion is set so that light emitted from the light emission end does not hit the inner surface of the large-diameter portion.   A tube in which the fiber holding portion has a smaller diameter than the lens holding hole, and the fiber holding portion is fitted to the inner circumference without a gap, and the outer circumference is fitted to the lens holding hole without a gap. The light irradiation apparatus according to claim 1, further comprising an adapter having a shape.   The light irradiation apparatus according to claim 3, wherein a taper surface for contacting and fixing the lens is formed on the irradiation target portion side of the adapter.   2. A plurality of fiber insertion holes for holding optical fibers in the housing are provided in a discrete manner, and the lens holding portion is configured to hold a lens corresponding to each optical fiber one by one. The light irradiation apparatus according to 2, 3, or 4.   There is further provided a single second lens that is positioned between the lens and the site to be irradiated and is formed so as to form an annular shape with the through-hole provided in the center. The light irradiation apparatus according to claim 5, wherein the irradiated light is refracted and collected at the irradiation target site.   The light irradiation device according to claim 1, 2, 3, 4, 5 or 6, wherein the lens holding part has an annular shape, and a plurality of lens holding holes are provided intermittently along the circumferential direction. 8. The light irradiation device according to claim 1, wherein the lens has a spherical shape.

Images