JP2006276828A - Optical module and manufacturing method for the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical module capable of fixing a lens firmly with high positioning precision without using any adhesive agent. <P>SOLUTION: The optical module has a lens member with a lens part and an installation part and a holding member for holding the lens member at the installation part. The installation part has a fused part for transmitting an irradiated laser beam and a first positioning part becoming a reference for positioning in an optical axial direction of the lens part. The holding member has a fusing part which is arranged opposite to the fused part and fuses itself into the fused part with the laser beam and a second positioning part which is abutted to the first positioning part in a fused state and positions the lens member. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an optical module incorporated in a camera or the like and a mounting structure between an optical member and a holding member of the optical module.

  In a focus detection device incorporated in a camera or the like, a distance measurement error occurs due to a positional deviation of the secondary imaging lens. Therefore, it is required to position and fix the secondary imaging lens to the holding member with high accuracy. Usually, an adhesive is used for fixing the secondary imaging lens. However, there are problems in that the lens is not necessarily fixed enough and the optical surface may be soiled due to adhesion of the adhesive. For this reason, fixing methods other than adhesion are still being pursued for fixing the secondary imaging lens.

For example, Japanese Patent Application Laid-Open No. 7-272302 (hereinafter referred to as Patent Document 1) discloses an objective lens device in which an objective lens is fixed to a lens holder by ultrasonic welding.
JP 7-272302 A

However, in the case of the above-mentioned Patent Document 1, it is necessary to locally heat the welding location with the contact of the ultrasonic welder. However, it is difficult to perform positioning with high accuracy by applying the contact to the welding location in the assembly work. is there. In addition, there is room for improvement in that the shape and layout of the lens and the holding member are restricted because the contact is applied to the welded portion.
The present invention is for solving the above-described problems of the prior art, and an object thereof is to provide an optical module capable of firmly fixing a lens with high positioning accuracy without using an adhesive, and a method for manufacturing the same. It is.

  1st invention is an optical module which has a lens member which has a lens part and an attaching part, and a holding member which holds a lens member by an attaching part, and the attaching part was irradiated from the opposite side to a holding member A lens-side fused portion that transmits laser light; and a first positioning portion that serves as a positioning reference in the optical axis direction of the lens portion, and the holding member is disposed to face the lens-side fused portion. A fused portion that is fused to the lens-side fused portion by laser light, and a second positioning portion that contacts the first positioning portion in a fused state and regulates the relative distance from the lens member. It is characterized by.

  A second invention is an optical module having a lens member having a lens portion and an attachment portion, and a holding member for holding the lens member by the attachment portion, wherein the attachment portion is to be melted to transmit the irradiated laser light. A holding portion and a first positioning portion that serves as a positioning reference in the optical axis direction of the lens portion, and the holding member is disposed facing the fusion-bonded portion and is fused to the fusion-bonded portion by laser light. And a second positioning portion that contacts the first positioning portion and positions the lens member in a fused state.

The third invention is characterized in that, in the first or second invention, the attachment portion is configured such that the thickness of the fused portion is set to be thinner than the thickness of the first positioning portion.
According to a fourth invention, in any one of the first to third inventions, the fusion part is set to have a higher absorption rate of the wavelength of the laser beam than the fusion-bonded part.
According to a fifth invention, in any one of the first to fourth inventions, the attachment portion further includes a condensing optical element portion for converging the laser light toward the fusion-bonded surface of the fusion-bonded portion. And

A sixth invention is characterized in that, in any one of the first to fifth inventions, the laser light transmission region of the mounting portion has the same transparency as the lens portion.
7th invention is a manufacturing method of the optical module which hold | maintains the lens member which has a lens part to a holding member, Comprising: The 1st positioning part provided in the lens member when fuse | melting a lens member and a holding member The lens member is positioned on the holding member by bringing the lens member into contact with a second positioning portion provided on the holding member.

  The eighth invention is characterized in that, in the seventh invention, fusion is performed by irradiating the holding member with laser light through the lens member while the lens member is held by the holding member.

  In the present invention, the lens member can be fused to the holding member and firmly fixed by the laser beam transmitted through the fused portion and irradiated to the fused portion. Further, in the fused state, the lens portion can be positioned with high accuracy by the contact between the first positioning portion and the second positioning portion.

(Description of the first embodiment)
1 to 7 are views showing a first embodiment of the optical module of the present invention. In the first embodiment, the optical module constitutes a camera focus detection device.
As shown in FIG. 1, the focus detection apparatus includes a lens holding member 11, an infrared cut filter 12 that removes an infrared component of incident light, an aperture mask 13, a separator lens 14, and an optical sensor package 15. ing.

The lens holding member 11 constitutes a main body portion of the focus detection device, and each component of the focus detection device is positioned and attached. The lens holding member 11 is formed of a thermoplastic resin (such as plastic) having a color that easily absorbs the wavelength of light, such as black.
In FIG. 1, openings are formed on the upper surface side (incident side) and lower left side (sensor mounting side) of the lens holding member 11, and the distance measuring light beam is separated from the incident side opening portion to remove unnecessary light fluxes. A field mask 16 is attached. The field mask 16 is formed with a plurality of rectangular openings 16a through which light flux from the subject passes.

Further, inside the lens holding member 11, a condenser lens and a folding mirror that reflects the light beam transmitted through the condenser lens to the opening 11a on the sensor mounting side are disposed (the condenser lens and the folding mirror are illustrated). (Omitted).
Further, as shown in FIG. 2, a recess 11b corresponding to the outer shape of the separator lens 14 is formed around the opening 11a on the sensor mounting side. An infrared cut filter 12, a diaphragm mask 13 and a separator lens 14 are arranged in the concave portion 11b in the order of assembly. Then, after the separator lens 14 is attached, the optical sensor package 15 is attached to the position of the recessed portion 11b of the lens holding member 11 from the outside. The lens holding member 11 and the separator lens 14 are fixed by laser fusion.

A stepped portion 11c for fitting the infrared cut filter 12 is formed around the opening 11a on the bottom surface of the recessed portion 11b in the depth direction in FIG. A pair of shaft portions 17 and 18 projecting in the insertion direction of the separator lens 14, a fused portion 19, and a positioning base portion 20 are formed on the bottom surface of the recessed portion 11 b.
The pair of shaft portions 17 and 18 are arranged on the left and right sides with the opening 11a therebetween. One shaft portion 17 located on the left side in the drawing has a circular cross section, and the other shaft portion 18 located on the right side in the drawing has protrusions formed at two upper and lower portions of the shaft body having the same shape as the shaft portion 17. Yes. Each projecting portion of the shaft portion 18 extends from the base end side along the axial direction, and the top surface of each projecting portion forms a horizontal plane along the shaft portion width direction.

The fused portion 19 and the positioning base portion 20 are both formed on the bottom surface of the recessed portion 11b. The fused portion 19 is disposed around the shaft portions 17 and 18 with a space therebetween. On the other hand, two positioning bases 20 are disposed in the vicinity of the upper side of the separator lens 14 and two in the vicinity of the lower side.
The fused portion 19 and the lens positioning base portion 20 are cylindrical pedestals that protrude in the insertion direction of the separator lens 14, and their tip portions form a flat surface parallel to the bottom surface of the recessed portion 11 b. The height of the positioning base portion 20 (the amount of protrusion from the bottom surface of the recessed portion) is set slightly lower than the height of the fused portion 19.

  The aperture mask 13 is formed with a plurality of circular openings 13a through which the light flux from the folding mirror passes. Further, the diaphragm mask 13 is notched at portions where it interferes with the fused portion 19 and the positioning base portion 20, and through holes 13b are formed at positions corresponding to the shaft portions 17 and 18 on both sides thereof. When the focus detection device is assembled, the shaft portions 17 and 18 are inserted into the respective insertion holes 13b.

  The separator lens 14 is made of a light-transmitting thermoplastic resin (plastic or the like), and can transmit a distance measuring light beam and a laser beam described later. The separator lens 14 has a lens portion 14a configured by arranging a plurality of pairs of lenses, and a mounting portion 14b formed on the outer peripheral portion of the lens portion 14a. The lens unit 14a serves to form an image of the distance measuring light beam that has passed through the aperture mask 13 on the sensor.

  Positioning holes 21 and 22 are formed in the attachment portion 14b at positions corresponding to the shaft portions 17 and 18 with the lens portion 14a interposed therebetween. The positioning holes 21 and 22 are opened along the optical axis direction of the lens portion 14a. One positioning hole 21 located on the left side in the figure is formed in a circular shape, and the other positioning hole 22 located on the right side in the figure is formed as a long hole extending in the width direction of the separator lens 14. The one positioning hole 21 is fitted to the one shaft portion 17 and defines the translational movement of the surface perpendicular to the optical axis direction of the lens portion 14a. Further, the other positioning hole 22 is fitted to the other shaft portion 18 having the projection portion, and defines the rotational movement of the surface perpendicular to the optical axis direction of the lens portion 14a.

  A lens-side fused portion 23 is formed at a position corresponding to the fused portion 19 on one surface of the mounting portion 14 b, and a lens-side positioning base portion 24 is formed at a corresponding position of the positioning base portion 20. The lens-side fused portion 23 and the lens-side positioning base portion 24 are cylindrical pedestals that protrude in the optical axis direction of the lens portion 14a, and their tip portions form a flat surface perpendicular to the optical axis of the lens portion 14a. ing. The height of the lens-side positioning base 24 (the amount of protrusion from one surface of the mounting portion 14b) is set slightly lower than the height of the lens-side fused portion 23.

Further, on the other surface of the attachment portion 14b, the positioning holes 21 and 22 and the back side portions of the lens-side fused portion 23 are cut out into a rectangular shape and recessed. Therefore, the thickness in the optical axis direction of the lens side fused portion 23 is thinner than the thickness in the optical axis direction of the lens side positioning base portion 24.
Further, as shown in FIG. 7, the surface of the separator lens 14 is roughened by polishing, blasting or the like, except for the optical surface of the lens portion 14a and the flat surface of the lens-side fused portion 23 and the back surface thereof. Is given. Therefore, irregular reflection and generation of stray light are suppressed at the rough surface portion of the separator lens 14. On the other hand, in the laser light transmission region from the flat surface of the lens-side fused portion 23 to its back surface, the same light transmittance as that of the lens portion 14a is secured. Therefore, when laser light is irradiated on the back surface of the lens-side fused portion 23 in parallel with the optical axis of the lens portion 14 a, the laser light is transmitted through the attachment portion 14 b and from the flat surface of the lens-side fused portion 23. It is injected almost as it is.

Here, a laser fusion process between the lens holding member 11 and the separate lens 14 will be described with reference to FIGS.
FIG. 5 is a longitudinal sectional view showing a state before the lens holding member 11 and the separator lens 14 are fused. In FIG. 5, a separator lens 14 facing one surface is attached to the recessed portion 11 b of the lens holding member 11. In this attached state, the tip of the fused portion 19 and the tip of the lens side fused portion 23 are mutually connected. In contact. On the other hand, the tips of the positioning base 20 and the lens side positioning base 24 are opposed to each other with an interval L therebetween.

  At the time of fusion, laser light is irradiated to the lens-side fused portion 23 from the other surface side of the separator lens 14 (opposite side to the lens holding member 11). The laser light passes through the lens-side fused portion 23 and melts the interface portion (the lens-side fused portion 23 and the tip surface of the fused portion 19) with the holding member 11 where the absorption rate of the wavelength of the laser light is increased. To do. Thereby, the lens holding member 11 and the separator lens 14 are fused. At the time of fusion, the joint portion between the fused portion 19 and the lens side fused portion 23 has a large diameter due to the melted resin, but the fused portion 19 and the lens side fused portion 23 are the shaft portions 17 and 18. Further, since the positioning bases 20 and 24 are spaced from each other, there is no interference between the members at the time of fusion.

  On the other hand, the lens holding member 11 and the separator lens 14 approach each other by the distance L due to the above melting, and the tip of the positioning base 20 and the tip of the lens side positioning base 24 come into contact with each other. Therefore, in the state after fusion shown in FIG. 6, the relative distance between the lens holding member 11 and the separator lens 14 is defined by the positioning base 20 and the lens-side positioning base 24.

  The optical sensor package 15 has a plurality of line sensors arranged on the surface facing the separator lens 14 (illustration of the line sensors is omitted). In the assembled focus detection device, the optical sensor package 15 detects two images divided by the separator lens 14. Based on the interval between the two images, a CPU (not shown) calculates a defocus amount (a shift amount from the in-focus position) using a known arithmetic expression.

Hereinafter, the effect of the focus detection apparatus of the first embodiment will be described.
In the first embodiment, since the lens holding member 11 and the separator lens 14 are firmly fixed by laser fusion, it is possible to prevent a decrease in optical performance due to rattling of the lens portion 14a after fusion. In the fused state, the relative distance between the lens holding member 11 and the separator lens 14 is defined by the positioning base 20 and the lens-side positioning base 24, so that the optical positioning of the lens portion 14b is performed with high accuracy.

  In the first embodiment, since the laser beam is irradiated to the lens-side fused portion 23 from the other surface side of the separator lens 14 to the pinpoint, the fusion work can be easily performed. Further, there is no great restriction on the shape and layout of the lens holding member 11 and the separator lens 14 due to the fusion work. In addition, since no adhesive is used for fixing in the first embodiment, the optical surface of the lens portion 14a is not soiled by the adhesive.

  In the first embodiment, by reducing the thickness of the lens-side fused portion 23 in the optical axis direction, the amount of laser light applied during fusion can be reduced, and unnecessary heat generation at the mounting portion 14b is suppressed. Further, since the fused portion 19 has a higher absorption rate of the wavelength of the laser beam than the lens-side fused portion 23, a high heat is generated at the interface between the lens-side fused portion 23 and the fused portion 19 during laser light irradiation. It becomes easy to generate | occur | produce and it can fuse | fuse in a shorter time.

  In the first embodiment, the flat surface and the back surface of the lens-side fused portion 23 to be a laser light transmission region are not roughened, and the laser light transmission region is the same as the lens portion 14a. Transmits light flux. Therefore, the laser light applied to the separator lens 14 efficiently reaches the interface between the lens-side fused portion 23 and the fused portion 19. Therefore, unnecessary thermal deformation of the separator lens 14 due to the laser beam is suppressed at the time of fusion.

(Description of Second Embodiment)
FIG. 8 is a front view showing a state in which the separator lens is attached to the lens holding member in the second embodiment. FIG. 9 is a longitudinal sectional view showing a state before the lens holding member 11 and the separator lens 14 are fused together in the second embodiment. In the following description of the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and redundant description is omitted.

  In the second embodiment, a convex lens-shaped condensing optical element 25 is integrally formed on the attachment portion 14 b of the separator lens 14. As shown in FIG. 8, four condensing optical elements 25 are formed on the other surface side of the attachment portion 14b. The formation position of each condensing optical element 25 corresponds to the position of the lens-side fused portion 23 on one surface side (see FIG. 9). The optical surface shape of the condensing optical element 25 is designed so that the light beam incident from the other surface side of the mounting portion 14b is converged to the vicinity of the flat surface (the surface to be fused) of the lens side fused portion 23. ing.

  Similarly to the first embodiment, the surface of the separator lens 14 is roughened except for the optical surfaces of the lens portion 14a and the condensing optical element 25 and the flat surface of the lens-side fused portion 23. (The illustration of the portion subjected to the roughening treatment is omitted since it is almost the same as FIG. 7). That is, in the laser light transmission region from the optical surface of the condensing optical element 25 to the flat surface of the lens-side fused portion 23, the same light transmittance as that of the lens portion 14a is ensured.

  Hereinafter, the state at the time of attachment of the lens holding member 11 and the separator lens 14 in 2nd Embodiment is demonstrated. First, as in the first embodiment, the separator lens 14 is arranged in the concave portion 11b of the lens holding member 11 with one surface side facing the concave portion 11b. Next, laser light is irradiated to the lens-side fused portion 23 from the other surface side of the attachment portion 14b. At this time, the condensing optical element 25 converges the laser light in the vicinity of the flat surface (the surface to be fused) of the lens side fused portion 23.

  The laser beam converged by the condensing optical element 25 melts the interface portion with the holding member 11 where the absorption rate of the wavelength of the laser beam is increased. Thereby, the lens holding member 11 and the separator lens 14 are fused. In addition, since the laser beam transmission region transmits the light beam in the same manner as the lens portion 14a, the laser beam efficiently reaches the interface portion with the holding member 11, and in this respect, the separator lens 14 is not required by the laser beam. Thermal deformation is suppressed.

Also in the second embodiment, the tip of the positioning base 20 and the tip of the lens side positioning base 24 come into contact with each other after fusion, and the lens holding member 11 and the separator lens 14 are contacted by the positioning base 20 and the lens side positioning base 24. Relative distance is defined.
The second embodiment has the following effects in addition to the same effects as those of the first embodiment. In the second embodiment, since the laser beam is converged by the condensing optical element 25, the lens holding member 11 and the separator lens 14 can be efficiently fused with a smaller amount of energy than in the first embodiment. In addition, in the second embodiment, the thermal deformation of the separator lens 14 due to the laser light is significantly suppressed as compared with the first embodiment, so that the optical module can be manufactured with higher accuracy.

(Supplementary items of the embodiment)
As mentioned above, although this invention has been demonstrated by said embodiment, the technical scope of this invention is not limited to the said embodiment. The optical module of the present invention is not limited to the positioning of the separator lens and the lens holding member of the focus detection device, and may be widely applied in the case of fixing the positioning of a general optical member.

  Further, the condensing optical element of the second embodiment is not limited to the optical surface of the convex lens, and may be, for example, a condensing prism or Fresnel lens. Further, the roughening treatment applied to the surface of the separator lens in the above embodiment may be replaced by a coloring treatment such as painting.

An exploded perspective view showing one embodiment of an optical module Enlarged view of the vicinity of the opening on the sensor mounting side of the lens holding member The front view which shows the attachment state of the separator lens in 1st Embodiment AA sectional view of FIG. The longitudinal cross-sectional view which shows the state before melt | fusion of the lens holding member and separator lens in 1st Embodiment A longitudinal sectional view showing a fused state between the lens holding member and the separator lens The figure which shows the part in which a roughening process is performed in a separator lens The front view which shows the attachment state of the separator lens in 2nd Embodiment. The longitudinal cross-sectional view which shows the state before melt | fusion of the lens holding member and separator lens in 2nd Embodiment

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 ... Lens holding member, 14 ... Separator lens, 14a ... Lens part, 14b ... Mounting part, 19 ... Fusion part, 20 ... Positioning base part, 23 ... Lens side fused part, 24 ... Lens side positioning base part, 25 ... Condensing optical element

Claims (8)

An optical module having a lens member having a lens portion and an attachment portion, and a holding member for holding the lens member at the attachment portion,
The mounting portion includes a lens-side fused portion that transmits laser light emitted from the side opposite to the holding member, and a first positioning portion that serves as a positioning reference in the optical axis direction of the lens portion. ,
The holding member is disposed to face the lens-side fused portion and is fused to the lens-side fused portion by the laser beam, and the first positioning portion in the fused state And a second positioning part that regulates a relative distance from the lens member by contacting with the lens member. An optical module having a lens member having a lens portion and an attachment portion, and a holding member for holding the lens member at the attachment portion,
The mounting portion includes a fused portion that transmits the irradiated laser light, and a first positioning portion that serves as a positioning reference in the optical axis direction of the lens portion,
The holding member is disposed so as to face the fused portion, and is fused with the fused portion by the laser beam and in contact with the first positioning portion in the fused state. An optical module comprising: a second positioning portion that positions the lens member.   The optical module according to claim 1, wherein the attachment portion is configured such that a thickness of the fused portion is set to be thinner than a thickness of the first positioning portion.   4. The optical module according to claim 1, wherein the fusion part is set to have a higher absorptance of the wavelength of the laser light than the fusion part. 5.   The said attachment part further has a condensing optical element part which converges the said laser beam toward the to-be-fused surface of the said to-be-fused part, The any one of Claims 1-4 characterized by the above-mentioned. The optical module as described.   6. The optical module according to claim 1, wherein the laser light transmission region of the attachment portion has the same transparency as the lens portion. A method of manufacturing an optical module for holding a lens member having a lens portion on a holding member,
When the lens member and the holding member are fused, the lens member is held by bringing the first positioning portion provided on the lens member into contact with the second positioning portion provided on the holding member. A method for manufacturing an optical module, characterized by comprising: 8. The optical module according to claim 7, wherein the fusion is performed by irradiating the holding member with a laser beam through the lens member in a state where the lens member is held by the holding member. Method.

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