JP2008188815A - Lens molding die - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make the light axis centers of first and second surfaces agree accurately with each other with regard to the whole of a pair of cavity insert dies provided in a multi-cavity lens die. <P>SOLUTION: A fixed die 20 includes specular pieces 23 forming an optical function transfer surface 23a, the cavity insert dies 22 having the specular pieces 23, and a die 21 in which a plurality of the cavity insert dies 22 are installed. A movable die 30 is similar in composition. The cavity insert dies 22 and 32 have positioning holes 24 and 34 and positioning pins 25 and 35. When the fixed die 20 and the movable die 30 are closed, the positioning pin 35 is engaged with the positioning hole 24, and the positioning hole 34 is engaged with the positioning pin 25. The cavity insert dies 22 and 32 have the two positioning holes 24 and 34 and the two positioning pins 25 and 35, respectively. The two positioning holes are arranged at point symmetry positions in relation to lens light axes, and the two positioning pins are arranged at positions shifted by 90° in relation to the positioning holes. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a mold for molding an optical lens, and in particular, when molding an optical lens, a lens molding mold in which the center of the first surface and the center of the second surface of the lens are not misaligned. It relates to types.

Conventionally, a mold for molding an optical lens is generally constituted by an upper mold and a lower mold as disclosed in Patent Document 1 below. The upper mold and the lower mold are respectively attached to a pair of mold plates facing on the same axis, and a guide shaft provided on one side of the mold plate is fitted into a guide hole provided on the other side and positioned. Is slidable. For example, when the upper die is slidable, a barrel die is attached to the lower die, and a lower die body portion provided with a lens molding surface is fitted into a cylindrical hole provided in the barrel die. In the upper mold, the upper mold body part fits into the cylindrical hole of the body mold, and the lens molding surface provided in the upper mold faces the lens molding surface provided in the lower mold on the same axis inside the cylindrical hole. Thus, a lens molding space is formed. A preheated glass material is placed on a lens molding surface provided in the lower mold, and the lens molding space is formed by closing the upper mold and the lower mold, and the lens shape is transferred to the glass material.
JP 2005-206430 A

  In the mold shown in Patent Document 1, the upper mold and the lower mold are configured such that the optical axis centers of the lens molding surfaces of the upper mold and the lower mold coincide with each other. However, the positional accuracy of the upper mold and the lower mold is uniquely determined by the positional accuracy between the mold plates determined by the guide shaft and the guide hole, and between the upper mold, the lower mold, and the body mold. Since the clearance is provided, there is a possibility that the upper mold and the lower mold are displaced in the opposite direction with respect to the trunk mold by the clearance.

  In addition, when a plurality of molds are taken, a plurality of lens molding surfaces are provided on each of the upper mold and the lower mold, so that the positional accuracy of the lens molding surface on the mold is also affected, and individual lens molding The final position accuracy of the optical axis center of the surface is further deteriorated. Therefore, matching the optical axis centers of all lens molding surfaces with high accuracy has to make each dimension of the mold with considerable accuracy, and there are many difficult problems.

  For the problem to be applied, the present invention attaches a plurality of nested molds to each of the upper mold and the lower mold, and eliminates the variation in the position of the nested mold by positioning the upper and lower nested molds. The optical axis center of the lens molding surface provided in the nesting mold can be aligned with high accuracy.

  A mold for molding a lens according to the present invention includes a nesting mold having an optical function transfer surface for transferring an optical function surface of a lens to each of a fixed mold and a movable mold, and a mold frame on which the nesting mold is mounted so that its position can be adjusted. With. The nesting mold is provided with positioning holes and positioning pins as positioning means for positioning the nesting molds when the fixed mold and the movable mold are closed. The movable positioning pin engages with the fixed positioning hole, and the movable positioning hole engages with the fixed positioning pin.

  The telescopic type includes two positioning holes and two positioning pins, respectively. The two positioning holes are arranged at point-symmetrical positions with respect to the lens optical axis. The positioning pin is disposed and embedded at a position shifted by 90 ° from the positioning hole about the lens optical axis. The positioning pin is also fitted with a fixing hole provided in the mold.

  According to the present invention, the optical axis centers of all lens molding surfaces provided in a multi-cavity mold can be aligned with high accuracy with a simple structure.

  A structure of a mold for molding an optical lens according to an embodiment of the present invention will be described. A lens molding die 10 shown in FIGS. 1 and 2 includes a fixed mold 20 and a movable mold 30. The fixed mold 20 includes a mold 21, a nested mold 22 attached to the mold 21 so that the position thereof can be adjusted, and a mirror piece 23 fitted in the nested mold 22, and the movable mold 30 has the same configuration. ing.

  A guide shaft 36 is provided on the mold 31 of the movable mold 30. The mold 21 of the fixed mold 20 is provided with a guide hole 26 that fits with the guide shaft 36, and the guide shaft 36 slides in the guide hole 26 to open and close the fixed mold 20 and the movable mold 30. Is called.

  Eight fan-shaped insert molds 22 are fitted into the mold 21 in a circular shape (see FIGS. 2 and 3). Although not shown, eight nested molds 32 are similarly fitted into the mold 31 of the movable mold 30 in a circular shape. The eight nested molds fitted in the mold frame 21 and the eight nested molds fitted in the mold frame 31 are arranged in pairs.

  As shown in FIG. 4, the insert mold 22 has a lens forming space 40 in the center. A hole 41 for fitting the mirror piece 23 is formed at the center of the lens molding space 40, and a flange forming surface 42 is provided therearound. The flange forming surface 42 forms a flange portion of the lens with the flange forming surface 52 (see FIG. 3) provided on the telescopic die 32 of the movable die 30.

  A mirror piece 23 is fitted in the hole 41, and an optical function transfer surface 23a is formed at the tip of the mirror piece 23. The optical function transfer surface 23a is a range formed as a shape according to a design shape for realizing a function of refracting incident light and outgoing light at a predetermined angle as an optical lens. It has become. The mirror surface piece 23 forms a lens shape in a space between the mirror surface piece 33 fitted in the hole 51 of the nested die 32 of the movable die 30.

  The positioning pin 25 penetrating through the fixing hole 27 provided in the mold 21 penetrates the nested mold 22 and the tip thereof protrudes from the nested mold 22. Since the holes of the positioning pin 25 and the nested die 22 are interference-fitted, the positioning pin 25 is firmly fixed to the nested die 22. Two positioning pins 25 are provided, and are arranged at positions 180.degree. Symmetrical about the optical axis of the mirror piece 23.

  Two positioning holes 24 are provided at positions rotated by 90 ° from the positioning pins 25. In the insert mold 32, a positioning hole 34 is provided at a position facing the positioning pin 25 on the same axis, and a positioning pin 35 is provided at a position facing the positioning hole 24 on the same axis.

  Next, the operation of the mold according to the present invention will be described. As described above, the guide shaft 36 provided in the mold 31 of the movable mold 30 is fitted into the guide hole 26 provided in the mold 21 of the fixed mold 20 and is guided and slid. The mold 30 is opened and closed.

  Here, the positioning pins 25 and the positioning holes 24 arranged in the insert mold 22 are alternately arranged at intervals of 90 ° around the optical axis of the mirror piece 23, and the center of a circle passing through the positioning pins 25 and the positioning holes 24. The optical axis is located at On the other hand, the positioning pins 35 and the positioning holes 34 arranged in the insert mold 32 are also alternately arranged at intervals of 90 ° around the optical axis of the mirror piece 33, and at the center of a circle passing through the positioning pins 35 and the positioning holes 34. The optical axis is located.

  Immediately before the mold 21 and the mold 31 are combined, the positioning pin 25 is fitted into the positioning hole 34 and the positioning pin 35 is fitted into the positioning hole 24. Since the locating pins 25 and 35 are fixed to the nesting molds 22 and 32 by an interference fit, the locating pins and the positioning holes provided in the nesting molds 22 and 32 coincide with each other and are located at the center positions thereof. The optical axis center of the optical function transfer surface 23a of the mirror surface piece 23 and the optical axis center of the optical function transfer surface 33a of the mirror surface piece 33 completely coincide with each other.

  In this way, the optical axis is aligned between the pair of nested molds 22 and 32. This optical axis alignment is performed independently for each of the eight sets of nested molds, so even slight variations in the individual nested molds do not matter.

  Although the multi-cavity mold has been described in the above-described embodiment, the present invention is not limited to this, and may be adopted as a single-cavity mold.

  In the above-described embodiment, the injection mold has been described. However, the present invention is not limited to this and may be employed in a mold press mold.

It is sectional drawing of the fixed mold | type and movable mold | type of the lens mold for injection molding by this invention. It is a perspective view which shows the formwork which inserted eight nested molds. It is a perspective view which shows the nested type for movable types. It is a perspective view which shows the nesting type for fixed molds.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Mold 20 Fixed type | mold 21,31 Mold frame 22,32 Nesting type | mold 23,33 Mirror surface piece 23a, 33a Optical function transfer surface 24,34 Positioning hole 25,35 Positioning pin 26 Guide hole 30 Movable type 36 Guide shaft

Claims (7)

In a mold for molding a lens having a fixed mold and a movable mold each including a nested mold having an optical function transfer surface for transferring the optical function surface of the lens and a mold frame on which the nested mold is adjustable. ,
The lens mold is characterized in that the nesting mold is provided with positioning means for positioning the nesting molds with each other when the fixed mold and the movable mold are closed.   2. The lens molding die according to claim 1, wherein the positioning means is a positioning pin and a positioning hole which are fitted to each other.   3. The mold for molding a lens according to claim 2, wherein the positioning holes are two positioning holes arranged at positions 180 [deg.] Symmetrical with respect to the lens optical axis.   4. The lens molding die according to claim 3, wherein the positioning pin is embedded at a position rotated by 90 [deg.] About the lens optical axis with respect to the positioning hole.   5. The lens molding die according to claim 2, wherein the positioning pin is fitted into a fixing hole provided in the mold.   6. The lens molding die according to claim 1, wherein the mold frame includes a plurality of the nested molds, and a plurality of lenses are molded at a time.   7. The lens molding die according to claim 1, wherein the optical function transfer surface is formed on a mirror piece attached to the nesting die.

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