JP2000135729A - Lens unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture a lens unit for grasping easily whether a resin molded lens is set correctly on a lens holder or not. SOLUTION: A resin molded lens 10 is provided with a lens face 11 having the positive power on the upper face of the lens and a plane section 12 formed on the outer periphery of the lens face and set vertically to the optical axis of the resin molded lens 10. A gate trace 13 of the mold gate shape for flowing in a resin liquid at the time of molding the lens remains protrudedly and integrally on a side face section 14 of the resin molded lens 10 which forms the peripheral edge of the resin molding lens 10, and the upper face of the gate trace 13 is on the same plane as the plane section 12 and forms the plane section 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin molded lens.

[0002]

2. Description of the Related Art In low-cost cameras such as some compact cameras and film units with lenses,
In order to suppress the manufacturing cost, a resin molded lens molded by an injection molding method is generally used as a photographing lens. Injection molding is a method of injecting a resin liquid at high pressure through a gate into a mold having a space that follows the external shape of the molded object, cooling it, solidifying it, and removing it after mass production is possible. Manufacturing costs can be reduced.

[0003] A general photographic lens made of glass has a circular outer shape in most cases. However, in the case of a resin molded lens, a resin liquid is poured into a part of an outer diameter of the lens due to its manufacturing method. A mold gate is provided, and when the resin liquid is injected, the resin liquid remaining on the gate solidifies, and a gate mark protruding from the lens side surface is formed integrally. Gate marks are necessary in the manufacturing process of resin molded lenses,
Since it is unnecessary when used, it is generally deleted, and as a method for the deletion, there is a D-cut method in which a part of the flat part of the resin molded lens is deleted so as not to protrude from the outer diameter of the lens. On the other hand, there is a method of leaving a gate mark protruding from the outer periphery of the lens.

The shape of the lens receiving portion formed on the lens holder for receiving the resin molded lens is simply circular in the case of the D-cut method, but is in the case of the method in which the gate mark is projected from the outer periphery of the lens and left. The gate receiving part for fitting the gate mark protruding from the resin molded lens side protrudes from the outer periphery of the lens holder, and the lens receiving part becomes an open circle. The gate mark position of the lens must be aligned and assembled.

In the D-cut method, the gate mark is removed so that the shape as viewed from above the resin molded lens becomes a "D" shape. It is not necessary to regulate the position of the lens side surface, and the resin molded lens can be assembled to the lens holder. For this reason, the method of leaving the gate mark protruding from the outer periphery is less suitable for assembling than the D-cut method of deleting the gate mark.

However, the size of the gate mark of a resin molded lens is determined by the minimum gate width due to the viscosity of the resin and the like.
The size of the gate mark relative to the shape of the resin molded lens becomes large, and it becomes difficult to perform the D-cut method with a small-diameter lens. In addition, small-diameter lenses are difficult to distinguish between front and back when assembling, and if the lens is installed at a position deep from the exterior part, even if the lens is dropped, it will rotate halfway and be mounted upside down. As a result, it is not possible to determine whether the assembly is correct or not at that time, resulting in poor productivity.

FIG. 5 shows a lens unit including a resin molded lens 42, a lens holder main part 43, and a lens holder 44 in a conventional D-cut system. At the time of assembly, the lens side surface 45 that forms the side surface of the resin molded lens 42
In other words, there is no need to perform the position control, that is, when the gate trace formed integrally with the resin molded lens during molding of the resin molded lens is not removed from the outer diameter of the resin molded lens, the gate formed when the gate trace is removed Whatever direction the surface 46 faces, the resin molded lens 42 can be assembled to the lens holder main part 43. For this reason, in the D-cut method, the processing of the main part 43 of the lens holder for receiving the resin molded lens 42 is simple, and the suitability for assembly is good.

[0008]

FIG. 6 (A) is a view perpendicular to the gate-facing surface 6 of the resin molded lens 2, the lens holder main part 3 and the lens holder 4 when the above-mentioned lens unit is normally assembled. 4 is a schematic cross-sectional view. A portion of the resin molded lens 2 except for an upper layer portion of the lens surface 7 is incorporated into the lens holder main portion 3. The lens holder 4 is assembled so as to cover the main part 3 of the lens holder, and exposes the protruding lens surface 7 of the resin molded lens 2 from a circular lens opening 8 formed on the upper surface of the lens holder 4. While fixing the molded lens, the lens holder 4 is fixed to the lens holder.

FIG. 6B shows the gate-facing surface 6 when the resin molded lens 2 is assembled upside down from the normal state.
3 is a schematic sectional view perpendicular to FIG. Since the lens surface 7 protruding from the resin molded lens 2 is completely fitted into the circular opening 9 formed in the lens holder main part 3, the resin molded lens 2 does not protrude from the upper surface of the lens holder main part 3, The lens holder 4 is assembled and fixed to the lens holder in exactly the same manner as in the normal state.

Therefore, it is difficult to detect the so-called reverse assembly trouble in which the resin molded lens 2 is assembled to the lens holder 3 in the opposite direction to the normal, so that the production is continued as it is, and the trouble is found after the production. It was not suitable for production.

The present invention has been made in view of the above circumstances, and has as its object to provide a lens unit that can easily determine whether or not a resin molded lens has been correctly set in a lens holder.

[0012]

In order to achieve the above object, according to the present invention, there is provided a resin molded lens manufactured by injection molding and having a gate mark extending integrally from a peripheral edge thereof, and a resin molding lens including the gate mark. In a lens unit including a lens holder that receives a lens and a lens holder that engages with the lens holder and presses the resin-molded lens against the lens holder, the lens unit is parallel to the optical axis of the resin-molded lens and has a gate mark. The gate trace is formed such that a cross section of the gate trace perpendicular to the extension direction of the lens holder has a shape in which the width of the upper side contacting the lens holder and the width of the lower side contacting the lens holder are different.

[0013] Further, the cross section is a trapezoid in which the upper side and the lower side form a short side and a long side, respectively.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a normal assembling positional relationship between a resin molded lens constituting a lens unit, a main part of a lens holder, and a lens holder. The lens unit 30 includes a resin molded lens 10 and a lens holder main part 1.
5 and a lens holder 20.

The resin molded lens 10 has a lens surface 11 having a positive power on its upper surface, and a flat portion 12 provided on the outer periphery thereof and perpendicular to the optical axis 10a of the resin molded lens 10.
Are formed. A gate mark 13 in the shape of a mold gate for allowing a resin liquid to flow during molding is left on the resin molded lens 10 so as to protrude integrally with a side surface portion 14 that forms the periphery of the resin molded lens 10. The upper surface of 13 is on the same plane as the plane portion 12 and forms the plane portion 12.

The lens holder main part 15 is molded of plastic or the like, and has a lens receiving part 16, a circular opening 17, a circular opening 17, and a side surface of the lens holder main part, which are cut out in a cylindrical shape for mounting the resin molded lens 10. And a gate receiving portion 18 into which a gate mark protruding from is inserted. The notch 1 having the same cross-sectional shape (see FIG. 2) as the gate trace 13 is inserted into the gate receiving portion 18 so that the gate trace 13 is fitted without a gap when the resin molded lens is normally assembled.
9 are formed.

The lens holder 20 is formed in a cylindrical shape from plastic or the like, and has a hollow inside so as to cover the lens holder main part 15. A circular lens opening 21 for exposing a part of the lens surface 11 of the resin molded lens 10 is formed on the upper surface of the lens holder 20, and the lens holder 20 is fixed to the lens holder on the side surface of the lens holder 20. Engaging portion 22 and a gate receiving portion 18 protruding from a side surface of the lens holder main portion 15.
A notch 23 is formed to allow the lens holder 20 to penetrate through the side surface of the lens holder 20. The shape of the engaging portion 22 is not limited to this.

The resin molded lens 10 is a lens holder main part 1.
5, a notch portion 19 formed in a gate receiving portion 18 protruding from a side surface of a lens holder main portion 15 and having a gate mark 13 protruding from a side surface portion 14 forming a peripheral edge of the resin molded lens 10. Fit into.
Further, the lens holder 20 is assembled so as to cover the lens holder main part 15 and the resin molded lens 10, and is fixed to the lens holder via the engaging part 22, thereby forming the lens unit 30.

FIG. 2 is a cross-sectional view of the gate mark 13 which is parallel to the optical axis of the resin-molded lens 10 and is perpendicular to the extension direction of the gate mark 13 extending from the peripheral edge when the resin-molded lens 10 is molded. It is shown. The section 24 has a trapezoidal shape in which the lower side 25 of the lens surface 11 in contact with the lens holder 20 is longer than the upper side 26 facing the lens holder 15. The angle θ of the side of the trapezoid is more than the draft angle provided for taking out the molded product from the conventional mold, and is suitably in the range of 10 ° to 45 °.

Next, the operation of the above configuration will be described.
FIG. 3 shows the resin molded lens 10, the lens holder main part 15, and the lens holder 20 when the lens assembling system is normally assembled.
3 is a schematic cross-sectional view having a perpendicular to the cross-section 24 of the gate trace 13 showing the positional relationship of FIG. By matching the position of the gate receiving portion 18 of the lens holder main portion 15 with the position of the gate mark 13, the gate mark 13 is fitted into the cutout 19 of the gate receiving portion 18, excluding the upper part of the lens surface 11 of the resin molded lens 10. All parts are incorporated in the lens receiving portion 16 of the lens holder main portion 15.

The position of the notch 23 of the lens holder 20 coincides with the position of the gate receiving portion 18, and the lens surface 11 is exposed from the lens opening 21 so that the lens holder main part 15 is exposed.
In addition, the resin molded lens 10 can be completely covered. Further, the lens holder 20 is fixed to the lens holder via the engaging portion 22.

FIG. 4A shows that the resin molded lens 10
3 shows a cross section of the positional relationship between the gate trace 13 and the cutout portion of the gate receiving portion 18 when assembling is performed upside down from the time of normal assembly. The gate mark 13 is fitted into the notch 19 from the lower side 25 which is the long side of the trapezoid which is the cross-sectional shape of the gate mark 13 on the lens surface side.
It is impossible to lock and fit completely in the middle of the notch 19 having the same cross-sectional shape as that of FIG.

For this reason, as shown in FIG. 4B, the resin molded lens 10 is assembled into the lens holder main part 15 in an inclined state because the gate mark 13 is not fitted into the notch 19 of the gate receiving part 18. Then, a part of the resin molded lens 10 protrudes from the upper surface of the lens holder main part 15. Therefore, the lens holder 20 is attached to the lens holder main part 15 at an angle and cannot cover the lens holder main part 15 completely, and cannot be fixed to the lens holder via the engaging part 22. .

Therefore, in contrast to the conventional lens mounting system in which it is difficult to determine the appearance from the outside even when the lens is mounted upside down, the resin molded lens 10 is erroneously turned upside down from that in normal mounting. Even if the lens holder is incorporated in the lens receiving portion 18 of the lens holder main part 16, the lens holder is not fixed to the lens holder and is in an inclined state. A reverse assembly trouble can be easily confirmed in the middle of the process, and the suitability for production is improved.

[0025]

As described above in detail, according to the present invention, a resin molded lens manufactured by injection molding and having a gate trace extending integrally from a peripheral edge, and a lens for receiving the resin molded lens including the gate trace In a lens unit including a holder and a lens holder that engages with the lens holder and presses the resin molded lens against the lens holder, the lens unit is parallel to the optical axis of the resin molded lens and extends in the direction of the gate mark. Since the gate trace was formed such that the cross section of the gate trace forming a right angle had a shape in which the width of the upper side and the width in contact with the lens holder and the width of the lower side in contact with the lens holder were different, the resin molded lens was replaced with the lens holder. It is possible to provide a lens unit that can easily determine whether the lens unit has been correctly set.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a positional relationship of a resin molded lens, a lens holder main part, and a lens holder that constitute a lens unit of the present invention when the lens unit is normally assembled.

FIG. 2 is an explanatory diagram showing a cross section of a gate mark.

FIG. 3 is a cross-sectional view showing a positional relationship when a resin molded lens, a main part of a lens holder, and a lens holder are normally assembled.

FIG. 4 is a cross-sectional view showing a positional relationship when a resin molded lens, a main part of a lens holder, and a lens holder are reversely assembled.

FIG. 5 is a perspective view showing a positional relationship when a conventional D-cut resin molded lens, a lens holder main part, and a lens holder are normally assembled.

FIG. 6 is a cross-sectional view showing a positional relationship between the resin molded lens, the main part of the lens holder, and the lens holder shown in FIG. 5 during normal assembly and reverse assembly.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Resin molded lens 15 Lens holder main part 20 Lens holding 11 Lens surface 13 Gate mark 18 Gate receiving part 19 Notch 22 Gate mark cross section 25 Lower side 26 Upper side 30 Lens unit

Claims (2)

[Claims] 1. A resin molded lens which is manufactured by injection molding and has a gate trace integrally extending from a peripheral edge, a lens holder for receiving the resin molded lens including the gate trace, and a lens holder engaged with the lens holder to engage with the lens holder. A lens unit comprising a lens holder for pressing a resin molded lens against the lens holder, wherein the cross section of the gate trace that is parallel to the optical axis of the resin molded lens and that is perpendicular to the extension direction of the gate trace is the lens unit. A lens unit, wherein the gate mark is formed such that the width of an upper side contacting a holder and the width of a lower side contacting the lens holder have different shapes. 2. The cross section is a trapezoid in which the upper side and the lower side form a short side and a long side, respectively.
The lens unit as described.