JP2006284991A - Lens unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lens unit which can seal the inside of the lens-barrel 1, without forming gaps due to the thermal expansion coefficient difference between the lenses 2a, 2b and the lens barrel 1, even if the temperature is changing. <P>SOLUTION: This lens unit makes the inside of the lens barrel 1 sealed by applying solders 5a, 5b in between the supports 3a, 3b located inside the lens barrel and the outer fringes of the lenses 2a, 2b. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an on-vehicle lens unit composed of a lens or various optical filters.

  In recent years, there has been an increasing demand for in-vehicle cameras used for vehicle back monitors and front side blind monitors. A lens unit used in such a vehicle-mounted camera is required to have moisture resistance.

  Therefore, a conventional lens unit for an in-vehicle camera has a configuration as shown in FIG.

  FIG. 4 shows a conventional lens unit.

  In FIG. 4, 11 is a case, 12 is a lens barrel, the opening of the case 11 is sealed by a pressing member 13, and the gap between the case 11 and the pressing member 13 is sealed by an O-ring 15b. The opening of the pressing member 13 is sealed by the lens 14, and the gap between the pressing member 13 and the lens 14 is sealed by an O-ring 15a.

For example, as the prior art, the following Patent Document 1 is cited.
JP 2004-295119 A

  In the conventional configuration, the lens 14 is installed in the lens barrel 12 and sealed with a rubber member such as an O-ring 15a. However, the difference in coefficient of thermal expansion between the metal lens barrel 12 and the glass lens 14 and the rubber ring 15a is very large. The O-ring 15a contracts, and a gap is generated between the lens 14 and the lens barrel 12, and the sealing structure cannot be maintained, so that moisture enters.

  Therefore, an object of the present invention is to provide a lens unit that maintains hermeticity even under temperature changes.

  In order to achieve this object, in the present invention, solder is interposed between the support portion on the inner peripheral surface of the lens barrel and the outer peripheral portion of the lens.

  As described above, according to the present invention, when the lens is installed in the lens barrel, the lens barrel and the lens are joined and integrated by soldering. It is possible to provide a lens unit that can reliably seal the inside of the lens barrel without causing a gap due to the above.

(Embodiment 1)
Hereinafter, the lens unit according to Embodiment 1 of the present invention will be described with reference to the drawings.

  FIG. 1 is a cross-sectional view of a lens unit in the present embodiment, and FIG. 2 is an exploded perspective view of the lens unit.

  In FIG. 1, the lens unit of the present embodiment includes a lens barrel 1 having a through-hole 1a, support portions 3a, 3b, and 3c provided at predetermined intervals on the inner peripheral surface of the lens barrel 1, and support for these. The lenses 2a, 2b, and 2c are in contact with and supported by the portions 3a, 3b, and 3c, respectively. Then, solder 5a and 5b are interposed between the support portions 3a and 3b and the lenses 2a and 2b to seal the inside of the lens barrel 1.

  The lens unit is installed in the through hole 1a in order from the lens 2a having a smaller diameter with respect to the lens barrel 1, and the lens 2a is attached to the support portions 3a, 3b, and 3c corresponding to the diameters of the lenses 2a, 2b, and 2c. The distance between the lenses is defined by abutting the outer peripheries of 2b and 2c, and the optical axis 6 is adjusted by such a configuration.

  Further, in this lens unit, the metallization process 4 is performed on the outer periphery of the lens 2a and the lens 2b as shown in FIG. As shown in FIG. 1, solders 5a and 5b are placed on the upper surfaces of the support portions 3a and 3b provided on the inner peripheral surface of the lens barrel 1, and the lenses 2a and 2b are placed on the solders 5a and 5b and heated. The lens barrel 1 and the lenses 2a and 2b are fixed by the above.

  Here, by performing the metallization process 4, the wettability of the lenses 2a, 2b and the solders 5a, 5b can be improved.

  As described above, the lenses 2a and 2b and the lens barrel 1 are integrated by soldering, and the inside of the lens barrel 1 is hermetically sealed. Therefore, the support portion 3a provided on the inner peripheral surface of the lens barrel 1 even under a temperature change, The inside of the lens barrel 1 can be reliably sealed without a gap due to the difference in thermal expansion coefficient between the outer peripheral portions of 3b and the lenses 2a and 2b.

  As the heating means for the solders 5a and 5b, known means such as a hot plate and reflow can be used. Also, after the solders 5a and 5b heated and melted in advance are applied on the support portions 3a and 3b, the lenses 2a and 2b are applied. Can also be fixed.

  Furthermore, the thickness of the solders 5a and 5b between the support portions 3a and 3b and the lenses 2a and 2b can be reduced by mixing the particles 7 having a uniform particle size having a melting point higher than that of the solder into the solders 5a and 5b. The particles 7 contained in the solders 5a and 5b are also simultaneously smoothed when being smoothed by the pressure contact force caused by the insertion of the lenses 2a and 2b. That is, the multilayer structure of the solders 5a and 5b does not occur between the lenses 3a and 3b and the lenses 2a and 2b, and the thickness of the solders 5a and 5b is determined by the particle size of the particles 7. By controlling the pressing force to be equal to or higher than a predetermined pressure at which the particle size 7 is smoothed, the positional accuracy of the lenses 2a and 2b can be easily stabilized. For this reason, it becomes possible to control the optical distance between the lenses 2a, 2b, and 2c in units of μm, and it is possible to suppress the deterioration of the positional accuracy of the lens unit and the deterioration of the optical characteristics in assembling the lens unit.

  Further, by selecting a solder having a melting point higher than that of the solder 5b, the solder 5a fixing the lens 2a is not melted when the lens 2b is fixed. Can be prevented.

  In this lens unit, the lens barrel 1 is made of metal or ceramic, and the lenses 2a and 2b are made of glass or ceramic, so that expansion at the time of moisture absorption can be suppressed, and high reliability is realized even under high humidity. It becomes possible. In addition, when the lens barrel 1 is made of ceramic, wettability with the solders 5a and 5b can be ensured by performing metallization 4 on the surfaces of the support portions 3a and 3b.

  Further, by selecting an intermediate value between the linear thermal expansion coefficient of the lens barrel 1 and the linear thermal expansion coefficient of the lenses 2a and 2b as the linear thermal expansion coefficient of the solders 5a and 5b, the lens barrel 1 and the lens at a high temperature are selected. Since the concentration of stress on 2a and 2b can be relaxed, peeling of the sealing portion and cracking can be prevented, and the occurrence of stress birefringence on the lens can be suppressed, and high reliability can be realized.

  In this embodiment, the lens unit sealing structure using the lens barrel 1 and the lenses 2a and 2b has been described. However, the present invention is not limited to this, and instead of the lens, an infrared cut filter, an ultraviolet cut filter, an ND filter, Various optical filters such as an optical low-pass filter may be used.

  In the present embodiment, the solders 5a and 5b are provided on the step portions 3a and 3b provided on the inner peripheral surface of the lens barrel 1, but the solders 5a and 5b may be applied to the lenses 2a and 2b. .

  Furthermore, in the present embodiment, the lens 2c is installed between the lenses 2a and 2b, but one or more lenses may be provided between the lenses 2a and 2b, and an infrared cut is used instead of the lens. Various optical filters such as a filter, an ultraviolet cut filter, an ND filter, and an optical low-pass filter may be used.

  As a method of installing the lens 2c inserted between the lenses 2a and 2b in the lens barrel, a method of applying an adhesive containing particles to the support portion 3c and bringing the lens 2c into contact is conceivable. It is done. Further, after the lens 2a is fixed to the support portion 3a, the upper surface of the outer peripheral portion of the lens 2a and the lower surface of the outer peripheral portion of 2c are brought into contact with each other to be held together and fixed to the inner peripheral surface of the lens barrel. A configuration is also possible. The method of inserting and fixing a plurality of lenses including the lens 2c between the lenses 2a and 2b as described above may be other than the above.

  FIG. 3 is a cross-sectional view of a lens unit according to another embodiment.

  Here, the description of the same part as the lens unit in the above-described embodiment is omitted.

  The lens unit in FIG. 3 can be inserted from both sides of the through-hole 1a of the lens barrel 1 in addition to the configuration of the lens unit described above, so that the difference in outer shape between the lens 2a and the lens 2b is small. It is effective for.

  In addition, by selecting the solders 5a and 5b having different melting points, the solder for fixing the other lens is not melted when fixing one lens, so that the workability is improved and the lens is excellent in reliability. Unit can be provided.

  A plurality of lenses including 2c can be inserted and fixed between the lenses 2a and 2b, and the same method as described above can be considered.

  The operations and effects of the lens unit configuration as described above are the same as those in the above-described embodiment.

  The lens unit of the present invention can maintain the sealing structure in the lens barrel even under a temperature change, and is useful as an application of an imaging element typified by an in-vehicle camera.

Sectional drawing which shows the lens unit in one Embodiment of this invention Exploded perspective view of the lens unit Sectional drawing which shows the lens unit in other embodiment of this invention. Sectional view showing a conventional lens unit

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Lens tube 1a Through-hole 2a Lens 2b Lens 2c Lens 3a Support part 3b Support part 3c Support part 4 Metallization process 5a Solder 5b Solder 6 Optical axis 7 Particles

Claims (7)

The lens barrel, the first and second support portions provided at predetermined intervals in the longitudinal direction of the inner peripheral surface of the lens barrel, and the first and second support portions are respectively supported by the first and second support portions. A lens unit comprising: a first optical element and a second optical element, wherein solder is interposed between the support portions and the outer peripheral portion of the optical element. The lens barrel, the first and second support portions provided at predetermined intervals in the longitudinal direction of the inner peripheral surface of the lens barrel, and the first and second support portions are respectively supported by the first and second support portions. First and second optical elements, and the first and second optical elements are inserted from the upper and lower openings of the lens barrel, respectively, and solder is interposed between the support portion and the outer peripheral portion of the optical element. The lens unit according to claim 1. The lens unit according to claim 1, wherein particles having a melting point higher than that of the solder and having a uniform particle diameter are mixed in the solder. 4. The lens unit according to claim 3, wherein a solder connecting the first support portion and the first lens is higher than a melting point of the solder connecting the second support portion and the second lens. The lens unit according to claim 1, wherein the first optical element and the second optical element are a lens, an infrared cut filter, an ultraviolet cut filter, an ND filter, or an optical low-pass filter. The lens unit according to claim 1 or 2, wherein a metallization process is performed on the outer peripheral portions of the first and second optical elements. The lens unit according to claim 1 or 2, wherein the lens barrel is made of ceramic, and the first and second support portions are metalized.

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