JP2005077894A - Laser splice method for optical part - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laser splice method for an optical part which can reduce deterioration of optical characteristics caused by positional deviation generated when fixing the optical part and environmental change, and failure resulting therefrom. <P>SOLUTION: When fixing a splice member, to which the optical part is fixed, to a splice base material, a resin of small thermal expansion and contraction is melted so as to fill up the clearance between the splice member and the splice base material instead of using an adhesive. Thus, the optical part can be fixed with little positional deviation at splice and in environmental temperature change, and failure resulting from the positional deviation of the optical part can be reduced, and the optical characteristics can be improved. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a laser bonding method for optical components such as an optical pickup.

  As a conventional laser joining method for optical components, there has been a method using an ultraviolet curable adhesive (for example, see Patent Document 1). The prior art will be described below with reference to the drawings. FIG. 5 shows a schematic diagram of a conventional method for fixing an optical component.

  In the figure, reference numeral 101 denotes an example of an optical component, which is a glass mirror that reflects light having an optical axis of B, and 102 is an aluminum alloy housing to which the mirror 101 is fixed. 103 is an adhesive having no commutative properties, 104, 105 and 106 are the same type of adhesive having commutative properties, both of which are excellent in adhesiveness with glass and aluminum alloys, have little shrinkage in curing, and hardly change in quality. For example, it is an epoxy adhesive that hardens when left for several hours. By using a dispenser or the like, it can always be applied in a certain amount.

  The operation of the conventional optical component fixing method having the above configuration will be described.

  In FIG. 5, adhesives 103, 104, 105 and 106 are applied on the housing 102, the mirror 101 is brought into contact with the housing 102 applied with the adhesive, and the optical axis B of the light reflected by the mirror is adjusted. While maintaining the posture (state), it is left for the time required for solidification. When the adhesives 103, 104, 105, and 106 are solidified, the optical component can be fixed. Of the four adhesives fixing the mirror 101, the binding force of the adhesive 103 that is not replaceable is strong, and suppresses the positional deviation and the collapse of the mirror 101 with respect to the housing 102.

Further, as the environmental temperature changes, the stress generated by the expansion and contraction of the mirror 101 and the housing 102 is absorbed by the deformable adhesives 104, 105, and 106, respectively. As a result, the mirror 101 on the housing 102 is not distorted.
JP-A 63-269323

  However, in the configuration as described above, when the gap between the mirror 101 and the housing 102 is small, curing shrinkage of the adhesives 103, 104, 105, and 106 and expansion / shrinkage due to environmental changes can be ignored. If it is large, it cannot be ignored, and there is a problem that the optical component is displaced. The reason is described below.

  The amount of the adhesives 103, 104, 105, 106 applied when fixing the mirror 101 and its housing 102 is substantially proportional to the size of the gap between the fixing points. In addition, the amount of shrinkage when the adhesives 103, 104, 105, and 106 are cured and the expansion / contraction caused by environmental changes are proportional to the amount of the adhesive. In addition, there is a problem in that the optical components are greatly misaligned when the environment changes, and the optical characteristics deteriorate.

  As the density of optical discs increases and the speed and performance of optical pickups increase, the precision, performance, and miniaturization of optical components are advancing, reducing the displacement of the fixed position and fixing the optical components with high precision. There is a need to. In the conventional technology, only the case of an epoxy adhesive is disclosed. However, even when an ultraviolet curable adhesive that is solidified by ultraviolet irradiation is used, expansion / contraction due to curing shrinkage / environmental change occurs. It becomes a problem.

  As described above, in the conventional fixing method, since expansion / contraction occurs, there is a problem that the optical component is displaced and the optical characteristics are deteriorated.

  In view of the above-described conventional problems, the present invention provides a laser joining method for optical components that can reduce the positional deviation of the optical components and improve the optical characteristics by reducing expansion and contraction that occur in the fixed portion. For the purpose.

  In order to achieve the above-described object, a laser joining method for optical components according to the present invention includes a step of adjusting a state of a joining member that holds an optical component with respect to a joining base material, A method for laser joining of optical components, comprising: a step of arranging a filler in which an absorbing material having a high absorption rate and a high melting point is dispersed in a gap between the joining base material and the joining member; and a step of irradiating the filler with laser light. The transmission material and the absorption material are heated by the laser beam to the melting point of the transmission material and below the melting point of the absorption material, respectively, and the transmission material is melted by heat conduction, and the gap between the bonding base material and the bonding member It is characterized by being fixed by filling.

  Alternatively, based on the image of the vicinity of the gap obtained by the step of adjusting the state of the joining member holding the optical component with respect to the joining base material and the observation means for enlarging the gap between the joining base material and the joining member. A step of determining a laser beam irradiation position at a position where the bonding base material and the bonding member can be bonded based on the calculated gap size, irradiating the bonding member with an irradiation position indicating laser beam, and the observation means After observing the irradiation position, the step of moving the focus of the irradiation position indicating laser beam to the irradiation position, and the welding laser beam whose optical axis coincides with the irradiation position indicating laser beam in the optical axis direction Moving and focusing on the irradiation position, irradiating the welding laser beam in the vicinity of the laser irradiation position of the joining member to partially melt the joining member, and bending the gap by thermal expansion and contraction. And the step of irradiating the laser beam for welding after measuring the gap and positioning by irradiation with the irradiation position indicating laser beam, and the laser irradiation position of the joining member by the laser irradiation for welding is Since the melting temperature is reached, the front end of the joining member is also sufficiently heated, and the front end of the joining member contacts the joining base material, so that the joining base material is melted and the joining member becomes the joining base material. An optical component laser joining method comprising a step of fixing the joining base material and the joining member by being buried and cooled.

  As described above, according to the laser joining method of the optical component of the present invention, it is possible to fix the optical component with a small positional deviation at the time of joining and environmental change, improve the optical characteristics of the optical component, and the positional deviation of the optical component. It is possible to reduce the defects related to.

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

(Embodiment 1)
FIG. 1 is a schematic diagram of a laser joining method for optical components according to Embodiment 1 of the present invention.

  In FIG. 1, reference numeral 1 denotes a cylindrical recess having a radius Rmm at a corner, a plate thickness larger than R, for example, a zinc base material used as a material, a base material for an optical unit, and 2 a base material 1. A joint member having a similar dent of radius Rmm at a position opposite to the dent, a plate thickness larger than R and separated from the joint base material 1 by a gap G, and holding an optical component using SPCC as a material, for example, 3 is a joint member A moving device fixed to 2 and capable of moving in the X, Y, Z, θx, θy, and θz directions, 4 is a transparent resin made of polycarbonate having a melting point T1 and an absorption rate of 10% or less for a wavelength λ1 = 808 nm. Material 5 is an absorber made of zinc alloy powder having a melting point T2 higher than the melting point T1 and having a transmittance of almost 0 with respect to the wavelength λ1 = 808 nm, and 6 is an elliptical spherical shape with a major axis of (2Rmm + gap G). Is also small (Rmm + gap G ), A filler in which the absorbing material 5 is scattered in the transmissive resin material 4, and an output of a maximum of 300 W is obtained for the filler 7, and parallel light having an oscillation wavelength λ1 = 808 nm is emitted, and the optical axis of the parallel light is The semiconductor laser oscillation device is fixed so as to pass through an intermediate point of the gap G between the bonding base material 1 and the bonding member 2.

  An apparatus for realizing the laser joining method of the optical component of the present invention is constituted by the above elements.

  According to such a configuration, the filler 6 is manually installed so that the filler 6 is placed in the recess of the bonding base material 1 and the recess of the bonding member 2, and the bonding member 2 is moved and fixed to the bonding member 2 by the moving device 3. After adjusting the posture (state) suitable for the optical component, the semiconductor laser oscillation device 7 is oscillated. At this time, the parallel laser light emitted from the semiconductor laser oscillation device 7 is always irradiated to the filler 6 because the optical axis is positioned at the intermediate point of the gap G between the bonding base material 1 and the bonding member 2. The laser light applied to the filler 6 passes through the transmissive resin material 4 in the filler 6 and is absorbed by the absorber 5, the temperature of the absorber 5 rises, and the absorbent material 4 has a melting point T 1 or higher. The absorbent 5 is not melted by heating to a temperature equal to or lower than the melting point T2 of 5, and only the permeable resin material 4 is melted by heat conduction from the absorbent 5. As the transparent resin material 4 is melted, the deformed filler 6 fills the gap G by its own weight as shown in FIG. 2, and is cooled and solidified after the laser irradiation is stopped, thereby fixing the bonding base material 1 and the bonding member 2. Is done.

According to the present invention, the transparent resin material 4 has a smaller thermal expansion / shrinkage amount than the ultraviolet curable adhesive, for example, an ultraviolet curable adhesive having a linear expansion coefficient of 5.3 × 10 ⁻⁵ / K. By selecting a polycarbonate that is approximately 2.7 × 10 ⁻⁵ / K, which is about ½, it is possible to reduce a positional shift due to a temperature difference during bonding and a positional shift during a reliability test.

  In this embodiment, a zinc alloy is used as a bonding base material. Instead, an aluminum alloy, a magnesium alloy, an iron-based alloy, stainless steel, a polymer resin may be used, and SPCC is used as a bonding member. Instead, other zinc alloys, aluminum alloys, magnesium alloys, other iron alloys, stainless steel, and polymer resins may be used.

  Moreover, although polycarbonate was used as the permeable resin material of the material for the filler 6, engineering plastics such as acrylic, liquid crystal polymer, polyphenic sulfide, polypropylene, and polyethylene may be used instead, and zinc alloy powder is used as the absorbent. Although used, instead, iron-based alloy, aluminum alloy, magnesium alloy, stainless steel, black polymer powder or pulverized material may be used. Although the filler 6 was manually installed, a parts feeder or a robot hand may be used instead of manual operation, and a semiconductor laser oscillation device 7 is provided as a heat source, but a YAG laser, a carbon dioxide laser, or an argon laser is used. May be.

(Embodiment 2)
FIG. 3 is a schematic diagram of a laser joining method for optical components according to Embodiment 2 of the present invention. 3, the same components as those in FIGS. 1 and 2 are denoted by the same reference numerals, and the description thereof is omitted.

  In FIG. 3, reference numeral 31 denotes a bonding base material which is a base of an optical unit using, for example, a polyphenyl sulfide (PPS) material having a melting point T3. Reference numeral 32 denotes a bonding base material 1 and a gap G away from the melting point T3 of the bonding member 31. A joining member holding an optical component using SPCC having a large melting point T4, 33 is a YAG laser oscillating device capable of pulsing at a maximum output of 300 W and emitting a parallel light with a wavelength λ2 = 1064 nm, 34 is a wavelength λ3 = 632 nm, maximum A He—Ne laser oscillation device that emits parallel light at an output of 12 mW, 35 is a parallel YAG laser beam emitted from the YAG laser oscillation device 34 and a parallel He—Ne laser beam emitted from the He—Ne laser oscillation device 35. The half mirror 36 that is installed so that the axes coincide with each other has a focal length f of wavelength λ2 = 1064 nm. , A convex lens having a focal length f3 (<f2) with respect to the wavelength λ3 = 632 nm, a condenser lens fixed so that the optical axis of the lens coincides with the optical axis of the emitted light of the YAG laser oscillation device 34, and 37 is a YAG laser. The parallel light oscillated from the oscillating device 33 passes through the half mirror 35, is converged by the condensing lens 36, and has a focal point at a position f2 away from the condensing lens 36, 38 is the YAG laser oscillating device 34, He. A laser optical system including a Ne laser oscillation device 35, a half mirror 36, and a condenser lens 40; a moving device 39 fixed to the laser optical system 41 and movable in X, Y, Z, θx, θy directions; 40, a CCD The CCD camera 41 is fixed so that the normal direction of the element surface faces the direction of the laser irradiation position A, and the optical axis 41 coincides with the normal direction of the CCD element surface of the CCD camera 40. An imaging lens constituting a magnifying optical system that captures the laser irradiation position A and the gap G between the bonding base material 31 and the bonding member 32 in the field of view and forms an enlarged image on the image pickup device of the CCD camera 40; 41 is a moving device for moving the lens 41 in the optical axis direction of the lens, and 43 is joined to the laser irradiation position A by image processing based on the images of the laser irradiation position A and the gap G obtained by the CCD camera 40 and the imaging lens 41. A computer 44 for measuring the horizontal distance L and the gap G from the end of the member 32, and 44 for displaying the image of the laser irradiation position A and the gap G obtained by the CCD camera 40 and the imaging lens 41. It is a monitor. The above elements constitute an apparatus for realizing the present invention.

  According to this configuration, the moving device 3 moves the bonding member 32 to adjust the posture (state) suitable for the optical component held by the bonding member 32, and then moves the imaging lens 41 near the gap G by the moving device 42. The image is moved to a position where the image is formed on the imaging device of the CCD camera 40, and the image of the gap G obtained by the CCD camera 40 is calculated by the computer 43 by image processing such as edge detection, and the size of the gap G is calculated. Ask.

  Next, as shown in FIG. 4, a distance L from the tip of the joining member 32 to the laser irradiation position A is determined. The angle from the horizontal of the joining member 32 obtained from the design dimensions of the member and θx, θy, and θz of the moving device 3 is examined in advance, and the maximum angle θ2 at which the joining member 32 can be bent by laser irradiation is checked in advance, and G <L × A position where (sin (θ1 + θ2) −sinθ1) is set as a laser irradiation position A.

  The moving device 42 moves the imaging lens 41 to a position where the vicinity of the laser irradiation position A is enlarged and imaged on the CCD camera 40 and observes an image near the laser irradiation position A on the monitor 44 while oscillating the He-Ne laser. After the apparatus 35 is oscillated and focused on the laser irradiation position A, the laser optical system 39 is moved in the Z direction by f3-f2, and the YAG laser is focused on the laser irradiation position A.

  The YAG laser oscillation device 34 is oscillated with the strength at which the bonding member 32 melts, the laser irradiation position A is melted, and the bonding member 32 is bent around the laser irradiation position A, so that the bonding member 32 and the bonding base material 31 can be bent. The gap G is reduced.

  Here, the principle of bending of the bonding member 32 by YAG laser irradiation is shown in FIG.

  In FIG. 5, FIG. 5A-1 shows a state immediately after the YAG laser beam 37 is irradiated on the bonding member 32, and an area near the laser irradiation position A is denoted by M. FIG. 5A-2 shows the temperature distribution when the region M shows the maximum temperature during irradiation with the YAG laser beam 37. The surface side irradiated with the YAG laser becomes the highest temperature TH, and the back surface of the bonding member 32 The temperature of TL is lower than TH. As the region M of the joining member 32 is melted, the surface temperature TH is higher than the back surface temperature TL, and therefore the amount of expansion on the side irradiated with the YAG laser light 37 as shown by the arrow increases, as shown in FIG. The shape is as shown.

  After the irradiation of the YAG laser beam 37 is stopped, the temperature of both TH and TL decreases to the ambient temperature T0. The amount of thermal contraction at this time is proportional to the temperature difference, and TH-T0> TL-T0. Therefore, as shown in FIG. 5C, the amount of contraction on the side irradiated with the YAG laser light 37 in the region M is an arrow. As shown in FIG. 2, the joining member 32 is bent to the side irradiated with the YAG laser beam 37 as a result. Thereafter, based on the image of the gap G obtained by the CCD camera 40, the calculator 43 measures the change amount ΔG of the gap G before and after the irradiation of the YAG laser light 37, and the YAG laser light 37 is measured until the gap G <ΔG. Repeat irradiation.

  When G <ΔG, the tip of the joining member 32 comes into contact with the joining base material 31 by the next YAG laser light 37 irradiation. When the YAG laser beam 37 is irradiated, the region M of the bonding member 32 is heated to a melting point T3 or higher, for example, in the case of SPCC, to a melting point of 1000 ° C. or higher. Heated to a melting point T3 or higher of the base material 31. Therefore, by bending the bonding member 32 by irradiation with the YAG laser light 37, the resin-made bonding base material 31 starts to melt from the place where the bonding member 32 touches, and the bonding member 32 is buried in the bonding base material 31. Then, after the irradiation of the YAG laser beam 37 is stopped, the joining base material 31 and the joining member 32 are gradually cooled and solidified, and the joining base material 31 and the joining member 32 are fixed.

  As described above, since the members are fixed to each other without using an adhesive by the method described above, positional deviation at the time of joining and positional deviation due to environmental changes are less likely to occur.

  In the present embodiment, when the bonding strength is insufficient, the YAG laser light 37 irradiation may be repeated again from the once bonded state, or only at the laser irradiation position A when the YAG laser is repeatedly irradiated. Instead, the laser irradiation position A vicinity, for example, L may be the same, but you may irradiate a different location in the plate width direction.

  Alternatively, the region may be determined within a range of L ± ΔL and the irradiation position may be changed within the range. Furthermore, although a YAG laser oscillation device is provided as a heat source, a carbon dioxide laser, an argon laser, or a semiconductor laser may be used instead, and a He-Ne laser is used as an irradiation position support means, but a semiconductor laser is used instead. May be used.

  In addition, polyphenyl sulfide was used as the bonding base material, but instead, engineering plastics such as polycarbonate, acrylic, liquid crystal polymer, polypropylene, and polyethylene may be used, and SPCC was used as the bonding member, but zinc alloy was used instead. Aluminum alloy, magnesium alloy, other iron alloys, stainless steel, and brass may be used. In addition, although a condensing lens is provided to condense the YAG laser light, a spherical reflecting mirror may be used instead.

  The optical component laser joining method of the present invention is characterized in that since the optical component is fixed by a laser without using an adhesive, the positional deviation when the optical component is fixed and when the environment changes is small. It can also be used for fixing optical parts such as digital cameras.

Schematic diagram of laser joining method for optical components in Embodiment 1 of the present invention The enlarged view of the laser junction part in Embodiment 1 of this invention Schematic diagram of laser joining method for optical components in Embodiment 2 of the present invention The enlarged view of the laser irradiation position in Embodiment 2 of this invention Schematic diagram of deformation by laser irradiation in Embodiment 2 of the present invention Schematic diagram of conventional optical component fixing method

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Joining base material 2 Joining member 4 Transparent resin material 5 Absorbing material 7 Semiconductor laser oscillation device

Claims (9)

A step of adjusting the state of the bonding member holding the optical component with respect to the bonding base material, and a filler in which an absorbing material having a light absorption rate and a melting point higher than that of the transmission material is dispersed inside the transmission material. And a step of irradiating the filler with laser light, and a step of irradiating the filler with laser light. A laser joining method for optical parts, which is fixed by filling the gap between the joining base material and the joining member by heating to the melting point of the absorbing material or less, melting the transmission material by heat conduction, and filling the gap between the joining base material and the joining member. 2. The laser joining method for optical components according to claim 1, wherein the joining base material is at least one of zinc alloy, aluminum alloy, magnesium alloy, iron-based alloy, stainless steel, and polymer resin. 3. The laser joining method for an optical component according to claim 1, wherein the transmitting material is at least one of polycarbonate, acrylic, liquid crystal polymer, polyphenic sulfide, polypropylene, and polyethylene. The absorbent material is at least one of zinc alloy powder, iron-based alloy, aluminum alloy, magnesium alloy, stainless steel, black polymer powder, and pulverized material. A method for laser joining optical components as described in 1 above. It is calculated based on the image of the vicinity of the gap obtained by the step of adjusting the state of the joining member holding the optical component with respect to the joining base material and the observation means for enlarging the gap between the joining base material and the joining member. Determining a laser beam irradiation position at a position where the bonding base material and the bonding member can be bonded based on the size of the gap, and irradiating the bonding member with an irradiation position indicating laser beam, And moving the focal point of the irradiation position indicating laser beam to the irradiation position, and moving the welding laser beam whose optical axis coincides with the irradiation position indicating laser beam in the optical axis direction. Focusing on the irradiation position and irradiating the welding laser beam in the vicinity of the laser irradiation position of the joining member to partially melt the joining member, and bending and reducing the gap by thermal expansion and contraction And the step of measuring the gap and aligning with the irradiation position indicating laser beam irradiation and then irradiating the welding laser beam is repeated, and the laser irradiation position of the joining member is melted by the welding laser irradiation. Therefore, the tip of the joining member is also sufficiently heated, and the tip of the joining member comes into contact with the joining base material, so that the joining base material is melted and the joining member is in the joining base material. A method for laser joining optical components, comprising: a step of fixing the joining base material and the joining member by being buried and cooled. 6. The laser joining method for optical parts according to claim 5, wherein the joining base material is at least one of polycarbonate, acrylic, liquid crystal polymer, polyphenic sulfide, polypropylene, and polyethylene. 6. The laser joining method for an optical component according to claim 5, wherein at least one of a semiconductor laser oscillation device and a He-Ne laser is used as the irradiation position indicating laser beam. 6. The laser joining method for optical components according to claim 1, wherein the joining member is at least one of zinc alloy, aluminum alloy, magnesium alloy, iron-based alloy, stainless steel, and polymer resin. 6. The laser joining method for optical components according to claim 1, wherein at least one of a semiconductor laser oscillator, a YAG laser, a carbon dioxide laser, and an argon laser is used as the laser light.

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