JP2008216891A - Method for fixing optical component - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for fixing an optical component by which an optical component is fixed at high speed with high accuracy, and sufficient strength is obtained. <P>SOLUTION: In such a state that an attaching part 12 formed like a leaf spring of a lens fixing frame 1 is elastically displaced in the abutting direction of the lens 2, a thermoplastic adhesive 3 is melted by radiation of an infrared laser beam, so that the lens 2 is instantaneously attached to the attaching part 12. By canceling the elastic displacement of the attaching part 12 of the lens fixing frame 1, the restoring force of the attaching part 12 is always generated in an anti-abutting direction, so that the lens 2 and the lens fixing frame 1 are made to abut on each other at a positioning part 11 not through the thermoplastic adhesive 3. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method of fixing an optical component used when fixing an optical component to a fixed frame.

  In recent years, while downsizing of photographing apparatuses such as digital cameras has progressed, there are increasing opportunities for viewing on a large screen or printing and viewing with a size larger than A4 size. For this reason, there is a demand for higher image quality of captured images. In order to improve the image quality of the captured image, it is necessary to improve the processing accuracy and assembly position accuracy in addition to optimizing the lens design in the imaging apparatus. However, this complicates manufacture, assembly, and adjustment, and increasing the number of parts leads to an increase in cost.

  Currently, good lenses with few aberrations can be obtained with a small number of lenses due to advances in lens design tools and low cost of aspherical processing, but the lens fixing method is still UV-cured. It is common to use a mold adhesive. However, since this adhesive is liquid, handling at the time of application is inconvenient, and a technique for applying an appropriate amount to an appropriate place is required. Furthermore, the UV irradiation time required for curing takes several tens of seconds, and even if lens position adjustment such as eccentricity adjustment is performed, the lens position gradually increases due to uneven curing shrinkage until the adhesive is completely cured. Will change. As a result, the lens position may be shifted from a desired position.

  On the other hand, a lens fixing method has been proposed in which high speed and high accuracy are achieved by various devices. For example, in a method of fixing a lens by heat caulking (see Patent Document 1), when caulking the other surface with one surface of the lens in contact with a fixed frame as a positioning surface, thermoplasticity is applied to the caulking portion. An adhesive is applied in advance. The thermoplastic adhesive is melted by heat at the time of heating, and the function of adhering the lens to the fixed frame with this adhesive is imparted, so that even if the lens is disturbed, the position is hardly displaced.

The inventor of the present application has previously proposed the following lens fixing method (see Patent Document 2). In this lens fixing method, the lens fixing part and the positioning part are separately provided on the fixing frame, and the lens fixing part is melted by irradiating a laser to the lens fixing part, and the lens fixing frame is instantaneously bonded to the lens. Positioning with high accuracy is performed by pulling in the positioning part using the contraction force.
JP-A-10-96842 JP 2005-316044 A

  However, the conventional optical component fixing method has the following problems. That is, in the lens fixing method by heat caulking in Patent Document 1, heat is transmitted to a wide range other than the necessary portion (location), and there is a possibility that the portion other than the necessary portion of the lens frame is deformed. In addition, when the lens and the lens frame are downsized and the attachment parts of other components are close to each other, the influence is further increased. In addition, the space occupied by the caulking portion is necessary on the lens outer periphery and the lens upper surface, and there is a restriction when the parts are brought close to each other, which may be a barrier to downsizing the lens barrel.

  On the other hand, in the lens fixing method using the laser of Patent Document 2, the lens and the lens fixing frame are melted by instantaneously irradiating the laser only to the necessary part of the lens fixing frame to melt and expand the lens fixing frame. And join. Thereby, there is no influence of the heat transmitted over a wide range of the lens fixing frame, and the joining process can be greatly shortened. Further, along with this joining, the joining lens contracts after the laser irradiation is stopped and the joined lens obtains a pressing force against the contact surface of the lens fixing frame, thereby improving the positioning accuracy. However, since the bonding is not performed through an adhesive, it is difficult to set conditions for obtaining a required bonding strength particularly in the case of a glass lens. As a result, depending on the environmental temperature, a difference in expansion coefficient between the lens and the lens fixing frame may occur, which may cause peeling. Further, since the positioning structure uses the shrinkage force of the resin, it is difficult to make the conditions uniform, and the positioning accuracy cannot be sufficiently improved.

  Therefore, an object of the present invention is to provide an optical component fixing method capable of fixing an optical component at high speed and with high accuracy and obtaining a sufficient strength.

  In order to achieve the above object, an optical component fixing method according to the present invention includes an optical component fixing the optical component to the fixed frame by heating a thermoplastic adhesive interposed between the optical component and the fixed frame. In the fixing method, a positioning portion for positioning the optical component in the optical axis direction and an adhesive portion having elasticity are formed on the fixing frame, and before the optical component is fixed to the fixing frame, an additional process is performed. A first step of bringing the optical part into contact with the adhesive part through the thermoplastic adhesive by elastically displacing the adhesive part in the contact direction of the optical part by a pressure unit In the first state, the thermoplastic adhesive is heated and melted by a heating means, and then solidified, whereby the second state is obtained in which the optical component is bonded to the bonding portion. And the contact by the pressurizing means. Releasing the elastic displacement of the parts, by the restoring force of the adhesive portion, and having a third step of the optical component to the third state in contact with the positioning portion.

  The method for fixing an optical component according to the present invention is a method for fixing an optical component in which a thermoplastic adhesive interposed between the optical component and a fixing frame is heated to fix the optical component to the fixing frame. In the frame, a positioning part for positioning the optical component in the optical axis direction, and an adhesive part to which the optical component is bonded, the height of the upper surface in the optical axis direction being lower than the positioning part is formed, Before fixing the optical component to the fixing frame, the optical component is brought into contact with the adhesive portion via the thermoplastic adhesive, and the optical component is not brought into contact with the positioning portion where the thermoplastic adhesive is not present. A first step of bringing the optical component into contact with the positioning portion by heating and melting the thermoplastic adhesive by a heating means in the first state; Second to And degree, the heating was stopped by the heating means, by solidifying the thermoplastic adhesive described above melt, and having a third step of bonding the optical component on the bonding portion.

  In the optical component fixing method according to claim 1 of the present invention, the thermoplastic adhesive is heated by the heating means in a state where the adhesive portion of the fixing frame has elasticity and is elastically displaced in the contact direction of the optical component. It melts and the optical component adheres to the adhesive part of the fixed frame. When the elastic displacement of the adhesive portion of the fixed frame is released, the restoring force of the adhesive portion is always generated in the anti-contact direction, and the optical component and the fixed frame are in contact with each other at the positioning portion without the adhesive. Accordingly, the optical component can be fixed at high speed and with high accuracy, and sufficient strength can be obtained. Further, the positioning accuracy of the optical component in the optical axis direction can be increased. The optical component fixing method according to claim 2 is effective when the radial width of the fixing frame is narrow. According to the fixing method of the optical component according to the third aspect, the optical component can be instantaneously melted and fixed from the state in which the optical component is in close contact with the fixing frame via the thermoplastic adhesive. . Moreover, internal stress becomes small by using a thermoplastic adhesive, and adhesion peeling can be prevented. According to the fixing method of the optical component according to the fourth aspect, it is possible to easily apply and handle the thermoplastic adhesive.

  According to the method for fixing an optical component according to claim 5 of the present invention, the optical component is instantaneously fixed to the fixed frame by heating from the state in which the optical component and the fixed frame are in close contact via the thermoplastic adhesive. At the same time, the optical component and the fixed frame are in contact with each other at the positioning portion without the adhesive. Accordingly, the optical component can be fixed at high speed and with high accuracy, and sufficient strength can be obtained. Further, the positioning accuracy of the optical component in the optical axis direction can be increased. According to the optical component fixing method of the sixth aspect, the shape of the fixing frame can be simplified. The optical component fixing method according to claim 7 is effective when the radial width of the fixed frame is narrow. According to the fixing method of the optical component according to the eighth aspect, it is possible to prevent the adhesive from protruding outside the necessary range by forming the groove for collecting the adhesive. According to the fixing method of the optical component according to the ninth aspect, the optical component can be instantaneously fixed from the state in which the optical component is in close contact with the fixing frame via the thermoplastic adhesive. Moreover, internal stress becomes small by using a thermoplastic adhesive, and adhesion peeling can be prevented. According to the optical component fixing method of the tenth aspect, it is possible to easily apply and handle the thermoplastic adhesive.

  DESCRIPTION OF EMBODIMENTS Embodiments of an optical component fixing method according to the present invention will be described with reference to the drawings. The fixing method of the optical component of this embodiment is applied to the fixing method of the lens when fixing the lens to the lens fixing frame.

[First Embodiment]
FIG. 1 is a perspective view showing a structure of a lens fixing frame in the first embodiment. FIG. 3A shows the structure of the front lens fixing frame to which the lens is fixed, and FIG. 4B shows the structure of the rear lens fixing frame.

  The lens fixing frame 1 has a substantially ring shape. Around the front opening of the lens fixing frame 1, three positioning portions 11 and an adhesive printing portion 12 are provided on substantially the same circumference. Three wall portions 14 are provided on the outer circumference. Further, six groove portions 13 are formed so as to cross these circumferences. These numbers are not particularly limited. The positioning unit 11 positions the lens 2 in the optical axis direction. An adhesive for bonding to the lens 2 is applied to the adhesive printing portion (adhesive portion) 12 by printing. The groove part 13 is for forming the adhesive printing part 12 in a leaf spring shape. The wall portion 14 performs positioning in a plane perpendicular to the optical axis of the lens 2. On the other hand, the leaf spring forming thin portion 12b, which is the back side of the adhesive printing portion 12, is formed thin, and imparts leaf spring properties to the adhesive printing portion 12 (lowers the elastic modulus).

  FIG. 2 is a perspective view showing the appearance of the lens and the lens fixing frame. When fixing the lens 2 to the lens fixing frame 1, first, the thermoplastic adhesive 3 is applied on the adhesive printing portion 12 by printing. Here, as an example, a method of printing an adhesive by a tampo printing method is shown. The adhesive 3 at the time of printing is a liquid in which an adhesive solid component is dissolved in a solvent, and is adjusted to have a viscosity suitable for tampo printing. The shape of the tampo used when the adhesive is transferred from the plate and printed at a predetermined position can be freely processed. Moreover, since it shape | molds with elastic materials, such as a silicone rubber, the shape and position of a printing part are arbitrary. For example, printing is possible even with some unevenness and R-surface shape. In addition, by appropriately setting and managing the viscosity and printing conditions of the adhesive, the thickness of the printed portion can be managed with a variation of several μm. After the adhesive 3 is printed at a predetermined position of the lens fixing frame 1, the solvent is volatilized by drying, and the adhesive is solidified at room temperature. In this case, as a drying method, it may be dried by natural drying, or may be dried in a predetermined high temperature furnace.

  Here, the case where a lens is fixed with the thermoplastic adhesive of this embodiment is compared with the case where a lens is fixed with a conventional UV adhesive or a thermosetting adhesive. Conventionally, the lens and the lens fixing frame are positioned in contact with each other at a flat portion perpendicular to the optical axis, and an adhesive is generally applied to the gap between the lens side surface and the lens fixing frame wall. It was broken. However, if it becomes possible to provide the bonding surface between the lens and the contact surface of the lens fixing frame on the same plane as in this embodiment, the wall portion necessary for bonding the lens side surface is eliminated, and the lens barrel The diameter can be reduced.

  On the other hand, in the lens fixing method by heat caulking, a wall portion is indispensable on the outer periphery of the lens and the caulking claw portion protrudes from the upper surface of the lens. There was also a risk of becoming.

  Also, in the case of conventional UV adhesives and thermosetting adhesives, once cured, their properties change due to a chemical reaction, and the adhesiveness cannot be exhibited even if UV irradiation or heating is performed again. . For this reason, if it is left as it is with the liquid adhesive applied, concerns such as dust adhesion, dripping, and protrusion may occur. Therefore, it is inevitable that the coating process and the bonding process are performed continuously.

  Another reason for using the thermoplastic adhesive in the present embodiment is that it does not involve a curing reaction, so that curing / shrinkage is small, and internal stress generated at the interface with the bonded part can be reduced. . That is, adhesion peeling can be prevented. Here, the internal stress is proportional to the elastic modulus of the adhesive and the difference in expansion coefficient of the adhesive member. The glass lens and the resin lens fixing frame have a large difference in expansion coefficient. When fixing such dissimilar materials, even if the initial adhesive strength is sufficient, it peels off after the main curing and changes in environmental temperature. Problem is likely to occur. Therefore, it is necessary to interpose an adhesive having a low elastic modulus as much as possible to reduce internal stress and prevent adhesion peeling.

  The elastic modulus of the adhesive used in this embodiment is about 1 GPa. On the other hand, for example, in the case of a thermosetting epoxy adhesive, the elastic modulus often exceeds 10 GPa. Therefore, the internal stress can be reduced to 1/10 or less by using the thermoplastic adhesive. However, if the elastic modulus of the thermoplastic adhesive is too low, the positional accuracy may be deteriorated depending on the temperature environment. Therefore, the elastic modulus is preferably about 1 GPa.

  Moreover, as another optimal adhesive property, it is desirable that the temperature which exhibits adhesive force is 150 to 200 degreeC. If a heating temperature higher than this is required at the time of bonding, a large electric power and a long time are required for heating, and the effect of fixing at high speed cannot be obtained. It is also necessary to prevent the influence of heat on the lens fixing frame and the like.

  As described above, after the thermoplastic adhesive 3 is printed at a predetermined position of the lens fixing frame 1, the lens 2 is positioned in a plane perpendicular to the optical axis by the wall portion 14 of the lens fixing frame 1. Is called. Furthermore, when the lens 2 is pressed against the positioning unit 11, the lens 2 is positioned in the optical axis direction. FIG. 3 is a view showing a state in which the lens 2 is fixed to the lens fixing frame 1. FIG. 2A shows a front view, and FIG. 2B shows a cross-sectional view as viewed from the direction of the arrow EE in FIG.

  Next, how the lens 2 is fixed to the lens fixing frame 1 is shown. FIG. 4 is an enlarged view showing a main part when the lens 2 is fixed to the lens fixing frame 1. In a state where the lens 2 is in contact with the positioning portion 11 of the lens fixing frame 1 and the positioning is performed, the adhesive printing portion 12 and the adhesive 3 are not in contact with the lens 2 (see FIG. 1A).

  In this state, the lens 2 is pressed by the lens pressing jig 4 from the upper surface to the lower surface. At this time, since the lens 2 is in contact with the positioning portion 11 of the lens fixing frame 1, it does not move. Subsequently, the adhesive 3 is brought into contact with the lens 2 by pressing and deforming the thin plate spring forming thin portion 12 b with the welding jig 5 from the lower surface direction of the lens fixing frame 1. In this state, the laser beam is irradiated by irradiating the infrared laser beam 6 through the lens 2 toward the lens fixing portion where the lens 2 is in contact with the lens fixing frame 1 (see FIG. 4B). ).

  After the laser irradiation is stopped, the lens 2, the adhesive 3 and the lens fixing frame 1 are firmly bonded even if the lens pressing jig 4 and the welding jig 5 are removed (see FIG. 3C). Further, since the leaf spring-like adhesive printing portion (adhesive portion) 12 of the lens fixing frame 1 remains in a deformed state, a force for pressing the lens 2 against the positioning portion 11 (restoring force due to elasticity of the adhesive portion 12). Will work. About the elastic force of the adhesion part (leaf spring part) 12, optimization by a material and a shape is performed. Therefore, the leaf spring portion is not limited to the shape of the present embodiment, and may have an arbitrary shape.

  Here, the detail of the lens fixing method by laser welding is shown. The adhesive 3 printed on the adhesive printing portion 12 of the lens fixing frame 1 contains an infrared absorbing material such as carbon black. Accordingly, the adhesive 3 generates heat by irradiation with the infrared laser beam 6. However, if the amount of the infrared absorbing material such as carbon black is excessively added as the addition amount of the adhesive 3, an excessive heat is generated or the adhesive strength is reduced. Is preferably about 1 to 5% by weight. Then, by appropriately controlling the irradiation intensity and irradiation time of the laser, the adhesive 3 melts and exhibits an adhesive force, and the lens 2 is fixed to the lens fixing frame 1.

  As the infrared laser, a semiconductor laser or a YAG laser having a wavelength of 800 nm to 1100 nm is used. Further, when the spot diameter of the irradiated portion is focused to about φ0.2 to φ0.8 and the lens outer peripheral portion is sequentially irradiated at an output of about 1 to 2 w at a speed of 10 to 20 mm / s, a predetermined adhesive strength is obtained. Is obtained. Alternatively, the laser light may be divided into a ring shape having a width of about 0.2 to 0.8 mm by an optical system using a conical prism or the like, and irradiated to the entire outer periphery of the lens at the same time, about 10 w to 20 w. A predetermined adhesive strength can be obtained by irradiating with an output of 2 to 5 seconds.

  Further, the laser emission timing may be synchronized so that the member such as the positioning portion 11 is not irradiated with the laser beam, and the emission portion may be scanned on the outer circumference of the lens. Alternatively, the outside of the range where laser irradiation is necessary is shielded with a metal plate or the like, and the entire circumference of the lens is scanned from above by the method described above, or laser light formed in a ring shape using the optical system described above is used. It may be irradiated.

  As described above, in the fixing method of the optical component according to the first embodiment, the adhesive printing portion 12 which is the bonding portion of the lens fixing frame 1 is formed into a leaf spring shape and deformed in the lens contact direction (pressurization) ), The lens 2 is fixed instantaneously by infrared laser irradiation. When the deformation of the leaf spring portion is released, the restoring force of the leaf spring is always generated in the bonding portion, and the lens and the lens frame are in contact with each other in a positioning portion that does not (but does not include) an adhesive. Therefore, the positioning accuracy of the lens in the optical axis direction can be increased. That is, by using a thermoplastic adhesive and laser welding, the lens can be fixed at high speed and with high accuracy, and sufficient strength can be obtained.

  These conditions are an example for allowing a lens having a size of about φ5 to φ15 used in a digital camera or the like to have an adhesive strength of about 1 to 5 kg. Therefore, the present invention is not limited to the above-described embodiment, and can be appropriately set according to various conditions such as the shape of a fixed lens.

  In the present embodiment, the adhesive printing is performed on the lens fixing frame side. However, the present invention is not limited to this, and the adhesive printing may be performed on the lens side. . In this embodiment, the adhesive is printed on the lens fixing frame or the lens by tampo printing. However, the present invention is not limited to this. For example, after centering while holding the lens on the rotating shaft having the suction means, the applicator with the adhesive attached is brought close to the lens, and the lens is rotated and applied to the outer peripheral surface and end surface of the lens. It may be.

  The adhesive is not particularly limited as long as it is a material that is solid at the time of positioning adjustment before the bonding process, generates heat by a heating means such as laser irradiation, and exhibits adhesive force. For example, a hot melt sheet may be disposed between the lens fixing frame and the lens as an adhesive. In this embodiment, an adhesive having infrared absorptivity is used as the adhesive, but the adhesive is indirectly generated by imparting infrared absorptivity to the lens fixing frame and heating the lens fixing frame with an infrared laser. May generate heat.

  In this embodiment, the positioning portion and the adhesive printing portion are provided on substantially the same circumference outside the lens, but may be provided on different concentric circles.

[Second Embodiment]
FIG. 5 is a front view showing the shape of the lens fixing frame 21 in the second embodiment. FIG. 6 is a perspective view showing the shape of the lens fixing frame 21. Around the opening of the lens fixing frame 21, a lens positioning portion 21a for positioning the lens 22 in the optical axis direction, an adhesive printing portion 21b on which the adhesive 23 is printed, and the lens 22 are guided and guided in the radial direction. A wall portion 21e for positioning is formed on a concentric circle. Further, an adhesive reservoir groove 21c (see FIG. 8) is provided between the lens positioning part 21a and the adhesive printing part 21b, and between the adhesive printing part 21b and the wall part 21e.

  FIG. 7 is a cross-sectional view showing how the lens 22 is fixed to the lens fixing frame 21. The lens fixing frame 21 is a frame member for fixing the two lenses 22 and 24. A lens 24 is fixed to the lens fixing frame 21 in advance by heat caulking. A thermoplastic adhesive 23 is printed with a uniform thickness on the adhesive printing portion 21b which is a lens fixing portion of the lens fixing frame 21 by tampo printing.

  As in the first embodiment, the adhesive 23 is a liquid in which an adhesive solid component is dissolved in a solvent during printing, and is adjusted to have a viscosity suitable for tampo printing. The shape of the tampo used when the adhesive is transferred from the plate and printed at a predetermined position can be freely processed. Moreover, since it shape | molds with elastic materials, such as a silicone rubber, the shape and position of a printing part are arbitrary. For example, printing is possible even with some unevenness and R-surface shape. In addition, by appropriately setting and managing the viscosity and printing conditions of the adhesive, the thickness of the printed portion can be managed with a variation of several μm.

  After the adhesive 23 is printed at a predetermined position of the lens fixing frame 21, the solvent is volatilized by drying, and the adhesive is solidified at room temperature. In this case, as a drying method, it may be dried by natural drying, or may be dried in a predetermined high temperature furnace.

  When the lens 22 is fitted into the lens fixing frame 21 so as to be guided by the wall portion 21e of the fixing frame 21, the lens 22 comes into contact with the adhesive 23 (see FIG. 5A). At this time, since the adhesive 23 is solidified, the lens 22 is slightly movable in a plane perpendicular to the optical axis. On the other hand, the lens 24 is fixed to the lens fixing frame 21 in advance by heat caulking or the like, but its fixing position varies depending on variations in the shape of the lens fixing frame 21, conditions at the time of heat caulking, or the like. Therefore, precise positioning adjustment of the lens 22 is performed using a tool or the like so that the optical axis of the lens 22 is aligned with the optical axis of the lens 24.

  Here, the case where a lens is fixed with the thermoplastic adhesive of this embodiment is compared with the case where a lens is fixed with a conventional UV adhesive or a thermosetting adhesive. Conventionally, the lens and the lens fixing frame are positioned in contact with each other at a flat portion perpendicular to the optical axis, and an adhesive is generally applied to the gap between the lens side surface and the lens fixing frame wall. It was broken. However, if it becomes possible to provide the bonding surface between the lens and the contact surface of the lens fixing frame on the same plane as in this embodiment, the wall portion necessary for bonding the lens side surface is eliminated, and the lens barrel The diameter can be reduced.

  When a conventional UV adhesive or a thermosetting adhesive is used instead of the thermoplastic adhesive used in the present embodiment, the above positioning adjustment becomes difficult. In other words, in the case of conventional UV adhesives and thermosetting adhesives, once cured, their properties change due to chemical reaction, and even if UV irradiation or heating is performed again, the adhesiveness cannot be exhibited. . Therefore, it is necessary to adjust the positioning by moving the lens while the liquid adhesive is interposed between the lens and the lens fixing frame. Since this liquid adhesive deteriorates the positioning adjustment accuracy, it is necessary to maintain the lens adjustment state within the three-dimensional coordinates with a tool or the like. In addition, since the contact portion is provided, it is necessary to consider that the adhesive protrudes outside the necessary range when determining the coordinates in the optical axis direction of the lens.

  Another reason for using the thermoplastic adhesive in the present embodiment is that it does not involve a curing reaction, so that curing / shrinkage is small, and internal stress generated at the interface with the bonded part can be reduced. . That is, adhesion peeling can be prevented. Here, the internal stress is proportional to the elastic modulus of the adhesive and the difference in expansion coefficient of the adhesive member. The glass lens and the resin lens fixing frame have a large difference in expansion coefficient. When fixing such dissimilar materials, even if the initial adhesive strength is sufficient, it peels off after the main curing and changes in environmental temperature. Problem is likely to occur. Therefore, it is necessary to interpose an adhesive having a low elastic modulus as much as possible to reduce internal stress and prevent adhesion peeling.

  The elastic modulus of the adhesive used in this embodiment is about 1 GPa. On the other hand, for example, in the case of a thermosetting epoxy adhesive, the elastic modulus often exceeds 10 GPa. Therefore, the internal stress can be reduced to 1/10 or less by using the thermoplastic adhesive. However, if the elastic modulus of the thermoplastic adhesive is too low, the positional accuracy may be deteriorated depending on the temperature environment. Therefore, the elastic modulus is preferably about 1 GPa.

  Moreover, as another optimal adhesive property, it is desirable that the temperature which exhibits adhesive force is 150 to 200 degreeC. If a heating temperature higher than this is required at the time of bonding, a large electric power and a long time are required for heating, and the effect of fixing at high speed cannot be obtained. It is also necessary to prevent the influence of heat on the lens fixing frame and the like.

  After the positioning of the lens 22 is completed, the lens 22 is pressed against the lens fixing part (adhesive printing part) 21b of the lens fixing frame 21 with a force F as shown in FIG. The infrared laser beam 25 is irradiated toward the lens fixing portion 21b.

  The adhesive 23 printed on the lens fixing portion 21b includes an infrared absorbing material such as carbon black. Accordingly, the adhesive 23 generates heat by irradiation with the infrared laser 25. However, if the infrared absorbing material such as carbon black is added too much as the addition amount of the adhesive 23, it causes sudden heat generation or decreases the adhesive strength. About 1 to 5% by weight is preferable. Then, by appropriately controlling the irradiation intensity and irradiation time of the laser, the adhesive 3 melts and exhibits an adhesive force, and the lens 22 is fixed to the lens fixing frame 21.

  As the infrared laser, a semiconductor laser or a YAG laser having a wavelength of 800 nm to 1100 nm is used. Further, when the spot diameter of the irradiated portion is focused to about φ0.2 to φ0.8 and the lens outer peripheral portion is sequentially irradiated at an output of about 1 to 2 w at a speed of 10 to 20 mm / s, a predetermined adhesive strength is obtained. Is obtained. Alternatively, the laser light may be divided into a ring shape having a width of about 0.2 to 0.8 mm by an optical system using a conical prism or the like, and irradiated to the entire outer periphery of the lens at the same time, about 10 w to 20 w. A predetermined adhesive strength can be obtained by irradiating with an output of 2 to 5 seconds.

  These conditions are an example for allowing a lens having a size of about φ5 to φ15 used in a digital camera or the like to have an adhesive strength of about 1 to 5 kg. Therefore, the present invention is not limited to the above-described embodiment, and can be appropriately set according to various conditions such as the shape of a fixed lens.

  FIG. 8 is a cross-sectional view showing a main part when the lens 22 is positioned in the optical axis direction. FIGS. 8A and 8B correspond to FIGS. 7A and 7B, respectively. As described above, the lens fixing frame 21 is provided with the lens positioning part 21a, the adhesive printing part 21b, and the wall part 21e in a concentric circle from the effective lens diameter toward the outer diameter. An adhesive 23 is printed on the adhesive printing portion 21b. At this time, the height of the surface in the optical axis direction with which the lens 22 abuts has a relationship of the upper surface of the adhesive 23> the upper surface of the lens positioning portion 21 a> the upper surface of the adhesive printing portion 21 b. Each step of the three surfaces is about 5 to 30 μm.

  For example, when the lens positioning portion 21a of the lens fixing frame 21 is used as a reference surface as a specific design shape and printing thickness regulation amount, the step of the adhesive printing portion 21b is 10 ± 4 μm, and the adhesive printed thereon The thickness of 23 is set to 20 ± 5 μm. Thereby, in the state before the bonding process by the infrared laser, the lens 22 is in contact with the surface of the adhesive 23 without contacting the positioning portion 21a (see FIG. 8A).

  In this state, after the adjustment of the optical axis eccentricity of the lens 22 is completed, the lens 22 is pressed against the lens fixing frame 21 and the contact portion of the adhesive 23 is irradiated with infrared laser light. Since the adhesive 23 has infrared absorptivity, it generates heat. When the adhesive 23 exceeds the glass transition temperature, it softens and deforms. Due to the force F (see FIG. 7) pressed against the lens fixing frame 21, the lens 22 comes into close contact with the lens positioning portion 21a, and predetermined positioning is performed (see FIG. 8B).

  The adhesive 23 is deformed and fluidized while increasing the adhesion with the lens 22. By stopping the laser irradiation after a predetermined time, the adhesive 23 is cooled and solidified, and the adhesion with the lens 22 is completed. As described above, since the adhesive reservoir groove 21c is provided around the adhesive printing portion 21b, the adhesive overflowing from the adhesive printing portion 21b adheres to the lens positioning portion 21a during bonding. There is nothing.

  As described above, in the lens fixing method according to the second embodiment, the lens 22 is instantaneously fixed by laser irradiation from the state where the lens 22 and the lens fixing frame 21 are in close contact with each other via the adhesive 23. In addition, the lens 22 and the lens fixing frame 21 are in contact with each other at the lens positioning portion 21a without the adhesive 23 interposed therebetween. Therefore, the positioning accuracy of the lens in the optical axis direction can be increased. Moreover, since the groove part 21c is formed in the circumference | surroundings of the adhesive printing part 21b in which the adhesive agent 23 is printed, it can prevent that the adhesive agent 23 protrudes outside the required range.

  In this embodiment, the lens positioning portion 21a and the adhesive printing portion 21b are provided on the entire circumference, but may not be on the entire circumference, and may be divided into a plurality of locations (for example, 3 locations) on the circumference. May be provided. Further, the groove 21c for the adhesive reservoir is not particularly required, and may be provided as necessary from the printing position, the amount of adhesive, the range, and the like. For example, even if the printing area of the adhesive is small compared to the entire printing surface, the necessary adhesive force can be obtained, and if there is no risk of adhering to the positioning part even if the adhesive flows around when adhering, the adhesive pool Even if no groove is provided, no particular problem occurs.

  In addition, although the adhesive printing is performed on the lens fixing frame side, the present invention is not limited to this, and the adhesive printing may be performed on the lens side. It is sufficient that the positional relationship similar to that of the present embodiment is satisfied before. Further, the groove for storing the adhesive is provided on the lens fixing frame side, but may be provided on the lens side, or may be provided on both the lens side and the lens fixing frame side.

[Third Embodiment]
The lens fixing method of the third embodiment is mainly different from the second embodiment in the shape of the lens fixing frame. Components similar to those of the second embodiment are omitted. FIG. 9 is a front view showing the shape of the lens fixing frame 31 in the third embodiment. FIG. 10 is a perspective view showing the shape of the lens fixing frame 31. On the lens outer periphery (substantially the same circumference) of the lens fixing frame 31, there are a plurality of lens positioning portions 31a for positioning the lens 32 in the optical axis direction, and a plurality of adhesive printing portions 31b on which the adhesive 33 is printed. (In this embodiment, each of the three locations) is provided. Further, a wall portion 31e for guiding the lens 32 at the time of mounting is formed on a concentric circle. Further, an adhesive reservoir groove 31c is formed around the adhesive printing portion 31b. The structure of this embodiment is effective when the width from the effective lens diameter to the outer diameter is narrow and there is no space for sequentially providing the lens positioning portion and the adhesive portion radially outward as in the second embodiment. . In this embodiment, in consideration of the positioning accuracy, securing of the bonding area, etc., the lens positioning part and the adhesive printing part are provided in three places, respectively, but the number and the structure itself are not limited. Absent.

  FIG. 11 is a cross-sectional view showing how the lens 32 is fixed to the lens fixing frame 31. Similar to the second embodiment, the lens fixing frame 31 is a frame member for fixing the two lenses 32 and 34. The lens 34 is previously fixed to the lens fixing frame 31 by heat caulking. The thermoplastic adhesive 33 is printed with a uniform thickness on the lens fixing part (adhesive printing part) 31b of the lens fixing frame 31 by tampo printing (see FIG. 1A). After the positioning of the lens 32 is completed, the lens 32 is pressed against the lens fixing portion of the lens fixing frame 31 with a force F (see FIG. 5B), and in this state, the infrared laser light 35 is passed through the lens 32 to the lens fixing portion ( Irradiation is directed toward the adhesive printing portion 31b (see FIG. 4C).

  The laser irradiation method is not particularly limited. For example, the laser emission part may be scanned so that only the necessary part is irradiated with laser light, or the area where laser irradiation is not necessary, such as a positioning part, is shielded with a metal plate, etc. May be irradiated with a laser beam formed in a scanning or ring shape.

  The adhesive 33 printed on the lens fixing part (adhesive printing part) 31b contains an infrared absorbing material such as carbon black, and the adhesive 33 generates heat when irradiated with infrared laser. By appropriately controlling the irradiation intensity and irradiation time of the laser, the adhesive 33 melts and exhibits its adhesive force. Thereby, the lens 32 is fixed to the lens fixing frame 31.

  FIG. 12 is a cross-sectional view showing a main part when the lens 32 is positioned in the optical axis direction. 12A, 12B, and 12C correspond to FIGS. 11A, 11B, and 11C, respectively. As described above, the lens fixing frame 31 is provided with three lens positioning portions 31a and adhesive printing portions 31b alternately in substantially the same circumferential direction of the lens outer diameter. An adhesive 33 is printed on the adhesive printing portion 31b. At this time, the height of the surface in the optical axis direction with which the lens 32 abuts has a relationship of the upper surface of the adhesive 33> the upper surface of the lens positioning portion 31a> the upper surface of the adhesive printing portion 31b. Each step of the three surfaces is about 5 to 30 μm.

  Further, in the state before the bonding process by the infrared laser, the lens 32 is in contact with the surface of the adhesive 33 without contacting the positioning portion 31a (see FIG. 5B). In this state, after the adjustment of the optical axis eccentricity of the lens 32 is completed, the lens 32 is pressed against the lens fixing frame 31 and the adhesive 33 is irradiated with infrared laser light.

  As described above, since the adhesive has infrared absorptivity, it generates heat, and when it exceeds the glass transition temperature, it softens and deforms. Due to the force with which the lens 32 is pressed against the lens fixing frame 31, the lens 32 comes into close contact with the lens positioning portion 31a, and predetermined positioning is performed. Further, the adhesive 33 is deformed and fluidized while increasing the adhesion with the lens 32, and after a predetermined time, the laser irradiation is stopped, whereby the adhesive 33 is cooled and solidified, and the adhesion with the lens 32 is completed.

  At this time, since the adhesive overflowing from the adhesive printing portion 31b is accumulated in the adhesive reservoir groove 31c provided around the adhesive printing portion 31b, the adhesive does not adhere to the positioning portion 31a. It does not adhere within the effective diameter of the lens or the opening of the lens fixing frame. Note that the groove 31c for the adhesive reservoir is not necessarily provided, and may be provided as necessary from the printing position, the amount of adhesive, the range, and the like.

  As described above, the lens fixing method according to the third embodiment can obtain the same effects as those of the second embodiment, and is also effective when the width from the lens effective diameter to the outer diameter is narrow.

  In the second and third embodiments, the adhesive is printed on the lens fixing frame or the lens, but the present invention is not limited to this. Any material that is solid at the time of positioning adjustment before the bonding process, generates heat by heating means such as laser irradiation, and exhibits adhesive force. For example, a thick hot melt sheet is disposed between the lens fixing frame and the lens. Or an adhesive.

  In addition, an adhesive with infrared absorptivity was used, but the lens fixing frame was given infrared absorption, and the lens fixing frame was heated by an infrared laser, so that the adhesive was indirectly heated. May be.

  The present invention is not limited to the configuration of the above-described embodiment, and any configuration can be used as long as the functions shown in the claims or the functions of the configuration of the present embodiment can be achieved. Is also applicable.

  For example, in each of the above embodiments, a lens is used as a component to be fixed in order to improve the positioning accuracy and shorten the time of the bonding process. However, the present invention is not limited to this, and the present invention is also applicable to the case where other optical components such as filters and glass plates used in optical devices are fixed.

It is a perspective view which shows the structure of the lens fixing frame in 1st Embodiment. It is a perspective view which shows the external appearance of a lens and a lens fixing frame. It is a figure which shows the state in which the lens 2 was fixed to the lens fixing frame 1. FIG. FIG. 3 is an enlarged view showing a main part when the lens 2 is fixed to the lens fixing frame 1. It is a front view which shows the shape of the lens fixing frame 21 in 2nd Embodiment. 3 is a perspective view showing a shape of a lens fixing frame 21. FIG. FIG. 3 is a cross-sectional view showing a state in which a lens 22 is fixed to a lens fixing frame 21. It is sectional drawing which shows the principal part at the time of positioning the lens 22 in the optical axis direction. It is a front view which shows the shape of the lens fixing frame 31 in 3rd Embodiment. 3 is a perspective view showing a shape of a lens fixing frame 31. FIG. FIG. 4 is a cross-sectional view showing a state in which a lens 32 is fixed to a lens fixing frame 31. It is sectional drawing which shows the principal part at the time of positioning the optical axis direction of the lens 32. FIG.

Explanation of symbols

1, 21 Lens fixing frame 2, 22, 32 Lens 3, 23, 33 Thermoplastic adhesive 5 Welding jig 6, 25, 35 Infrared laser beam 11, 21a, 31a Positioning part 12, 21b, 31b Adhesive printing part ( Bonding part)
21c, 31c groove

Claims (12)

A method of fixing an optical component by heating a thermoplastic adhesive interposed between the optical component and a fixed frame to fix the optical component to the fixed frame,
In the fixed frame, a positioning part for positioning the optical component in the optical axis direction and an adhesive part having elasticity are formed,
Before fixing the optical component to the fixed frame, the optical component is elastically displaced in the contact direction of the optical component by a pressurizing unit, so that the optical component is attached to the adhesive portion via the thermoplastic adhesive. A first step of bringing into contact with the first state;
In the first state, the thermoplastic adhesive is heated and melted by a heating means, and then solidified, whereby a second state is achieved in which the optical component is bonded to the bonding portion. When,
And a third step of releasing the elastic displacement of the adhesive portion by the pressurizing means and bringing the optical component into contact with the positioning portion by a restoring force of the adhesive portion. And fixing method of optical parts. A method for fixing an optical component according to claim 1,
A method of fixing an optical component, wherein the positioning portion and the bonding portion are formed at a plurality of locations on substantially the same circumference of the fixing frame. A method for fixing an optical component according to claim 1 or 2,
The method of fixing an optical component, wherein the heating means is an infrared laser, and at least one of the thermoplastic adhesive and the fixing frame includes an infrared absorbing material. A method for fixing an optical component according to any one of claims 1 to 3,
The method for fixing an optical component, wherein the thermoplastic adhesive is applied in advance to at least one of the optical component and the bonding portion and then solidified at room temperature by drying. A method of fixing an optical component by heating a thermoplastic adhesive interposed between the optical component and a fixed frame to fix the optical component to the fixed frame,
A positioning part for positioning the optical component in the optical axis direction and an adhesive part to which the optical component is bonded are formed in the fixed frame, and the height of the upper surface in the optical axis direction is lower than the positioning part. ,
Prior to fixing the optical component to the fixing frame, the optical component is brought into contact with the adhesive portion via the thermoplastic adhesive, and the optical component is not brought into contact with the positioning portion where the thermoplastic adhesive is not present. A first step in a first state;
A second step of bringing the optical component into contact with the positioning portion in a second state by heating and melting the thermoplastic adhesive by a heating means in the first state;
And a third step of bonding the optical component to the bonding portion by stopping the heating by the heating means and solidifying the molten thermoplastic adhesive. A method of fixing an optical component according to claim 5,
The method for fixing an optical component, wherein the positioning portion and the bonding portion are formed on concentric circles having different fixing frames. A method of fixing an optical component according to claim 5,
A method of fixing an optical component, wherein the positioning portion and the bonding portion are formed at a plurality of locations on substantially the same circumference of the fixing frame. A method for fixing an optical component according to any one of claims 5 to 7,
A method for fixing an optical component, wherein a groove for storing an adhesive is formed around at least one of the optical component and the fixing frame. A method for fixing an optical component according to any one of claims 5 to 8,
The heating means is an infrared laser, and an infrared absorbing material is contained in at least one of the thermoplastic adhesive and the fixing frame. A method for fixing an optical component according to any one of claims 5 to 9,
The method for fixing an optical component, wherein the thermoplastic adhesive is applied in advance to at least one of the optical component and the bonding portion and then solidified at room temperature by drying. A method for fixing an optical component according to claim 10,
The method of fixing an optical component, wherein the thermoplastic adhesive has a thickness in a range of 20 ± 5 μm.   An optical device, wherein the optical component is fixed to the fixing frame by the optical component fixing method according to claim 1.

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