KR20150094460A

KR20150094460A - Plastic achromatic lens for headlight and producing apparatus thereof

Info

Publication number: KR20150094460A
Application number: KR1020140022423A
Authority: KR
Inventors: 은현수
Original assignee: 은현수
Priority date: 2014-02-11
Filing date: 2014-02-26
Publication date: 2015-08-19

Abstract

The present invention relates to a plastic acromatic lens, and more particularly, to a plastic acromatic lens having an incident light lens unit having a horizontal light incidence surface on which light is incident and having a concave lens surface on which light is emitted and formed of a first material having optical characteristics corresponding to the flint glass, ; And an outgoing lens part having a convex aspherical surface, which is coupled to the concave lens surface of the incident light lens part and has a convex aspherical surface to which light is emitted, and is formed of a second material having optical characteristics corresponding to the crown glass, The parts are integrally formed by injection molding.

Description

TECHNICAL FIELD [0001] The present invention relates to a plastic acromatic lens for a headlight,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a headlight lens, and more particularly, to a plastic acromatic lens whose chromatic aberration is corrected, and an apparatus for manufacturing the same.

Generally, automobiles are equipped with various equalization devices. Among them, the headlight is an important equalizer that secures the driving view of the driver at night. In this regard, a headlight structure for an automobile is disclosed in Japanese Patent Application Laid-Open No. 2003-0048708.

As headlights used in automobiles in the past, aspherical lenses molded and processed in glass are used. Glass lenses are heavier than plastic lenses, have lower productivity, and have a higher production cost. In recent years, the headlamps have been converted into LEDs, and plastic lenses with high price competitiveness are urgently needed to cope.

In addition, the plastic lens has a lower stiffness than the glass lens. In order to cope with this problem, the use of polycarbonate material can compensate for the stiffness, but Abbe's number is significantly lower than that of glass, which is disadvantageous in that it lacks the function as an optical material.

In addition, when a lens is manufactured using acrylic, which is a general plastic optical material, its rigidity is low and yellowing may occur when exposed to ultraviolet rays such as LED.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-described problems, and to provide a new type of plastic acromatic lens and a device for manufacturing the same which can correct chromatic aberration while having strength and optical characteristics corresponding to glass.

The above objects and various advantages of the present invention will become more apparent from the preferred embodiments of the present invention by those skilled in the art.

The object of the present invention can be achieved by a plastic acromatic lens and a manufacturing method thereof. The plastic acromatic lens of the present invention comprises: an incident-light lens unit having a concave lens surface having a horizontal light incidence surface on which light is incident, a light outgoing surface, and formed of a first material having optical characteristics corresponding to the flint glass; And an outgoing lens part having a convex aspherical surface, which is coupled to the concave lens surface of the incident light lens part and has a convex aspherical surface to which light is emitted, and is formed of a second material having optical characteristics corresponding to the crown glass, The parts are integrally formed by injection molding.

According to one embodiment, the first material is polycarbonate and the second material is acrylic (PMMA).

On the other hand, the object of the present invention can be achieved by an apparatus for manufacturing a plastic acromatic lens. An apparatus for manufacturing an achromatic lens of the present invention includes: a base mold as a center of a mold;

A lower mold coupled to a lower portion of the base mold; A first upper mold disposed on the base mold and having a first mold corresponding to the concave lens; A second upper mold disposed on the base mold and having a second mold corresponding to the convex lens; A coupling shaft coupling the first upper mold and the second upper mold to each other; And a rotation shaft for rotating the coupling shaft to sequentially dispose the first upper mold or the second upper mold on the upper portion of the base mold. After the base mold and the lower mold are assembled, A first material having optical characteristics corresponding to the post-flint glass disposed on the base metal mold is supplied and an injection lens part is injection-molded, and the rotation shaft is rotated to place the second upper mold on the upper part of the light- A second material having optical characteristics corresponding to the crown glass is supplied, and an outgoing lens part is injection-molded integrally with the incident light lens part.

According to an embodiment, the temperature of each section may be set differently, and the plastic acromatic lens integrally injection-molded on the incident light lens unit may be gradually moved to enhance the shrinkage ratio.

According to another aspect of the present invention, there is provided an illumination optical system, comprising: an incident light lens unit having a concave lens surface having a horizontal light incidence surface on which light is incident and having a light exit surface and formed of a first material having optical characteristics corresponding to a flint glass; And an outgoing lens part having a convex aspherical surface, which is coupled to the concave lens surface of the incident light lens part and has a convex aspherical surface to which light is emitted, and is formed of a second material having optical characteristics corresponding to the crown glass, And the projecting lens part is joined to or joined to the upper part of the incident light lens part by the plastic acromatic lens for headlight.

The plastic acromatic lens of the present invention has the optical characteristics of the acromat lens formed of the flint glass and the crown glass, and the chromatic aberration can be corrected since the concave lens surface and the convex aspheric lens surface are provided. In addition, it is possible to reinforce the stiffness which has been raised as a problem of the conventional plastic lens, and to minimize the sulfur change.

Further, in the apparatus for manufacturing a plastic lens, two different materials can be successively injection molded to produce a plastic acromatic lens at a time. Accordingly, it is possible to produce a plastic acromatic lens which is lightweight, low in manufacturing cost, and easy in processing characteristics.

In addition, the plastic acromatic lens of the present invention may be manufactured by injection molding two different materials, respectively, and then joining the interfaces.

1 is a schematic view showing a configuration of a plastic acromatic lens according to the present invention,
FIG. 2 is a schematic view showing the construction of an apparatus for manufacturing a plastic acromatic lens according to the present invention,
FIGS. 3 and 4 are views illustrating a process of manufacturing a plastic acromatic lens,
5 is an exemplary view showing a cooling process of the plastic acromatic lens,
FIGS. 6 and 7 are views illustrating another manufacturing process of the plastic acromatic lens of the present invention.

For a better understanding of the present invention, a preferred embodiment of the present invention will be described with reference to the accompanying drawings. The embodiments of the present invention may be modified into various forms, and the scope of the present invention should not be construed as being limited to the embodiments described in detail below. The present embodiments are provided to enable those skilled in the art to more fully understand the present invention. Therefore, the shapes and the like of the elements in the drawings can be exaggeratedly expressed to emphasize a clearer description. It should be noted that in the drawings, the same members are denoted by the same reference numerals. Detailed descriptions of well-known functions and constructions which may be unnecessarily obscured by the gist of the present invention are omitted.

1 is a schematic view showing a configuration of a plastic acromatic lens 100 according to the present invention. As shown, the plastic acromatic lens 100 according to the present invention includes an incident light lens unit 110 through which light is incident and an outgoing lens unit 120 coupled to the incident light lens unit 110 to discharge light to the outside do.

The incident light lens unit 110 includes a light incident surface 115 formed horizontally and a concave lens surface 111 formed to have a predetermined thickness from the light incident surface 115 and having a plate surface recessed. Here, the incident light lens unit 110 is made of a material having optical properties of flint glass, and the light output lens unit 120 is made of a material having optical properties of crown glass.

The plastic acromatic lens 100 of the present invention is formed of a plastic material to manufacture an achromatic lens by combining a flint glass and a crown glass to correct chromatic aberration and spherical aberration, thereby reducing manufacturing cost and improving productivity. That is, the conventional achromatic lens which minimizes the chromatic aberration by using the condensation and dispersion of the crown glass, which is a convex lens having different refractive indexes and the Abbe's number, and the flint glass, which is a concave lens, is made of a plastic material having the same optical characteristics. For this, the incident light lens unit 110 may be formed of PC (polycarbonate), and the light exit lens unit 120 may be formed of PMMA (acrylic).

The chart below shows acrylic (PMMA), crown glass, polycarbonate (PC). Fig. 6 is a chart showing the optical characteristics of the flint glass. Fig. As shown, acrylic has optical properties similar to crown glass, and polycarbonate has optical properties similar to flint glass.

PMMA Crown glass PC Flint glass Refractive index 1.491 1.523 1.586 1.63 Abe number 57.6 58.5 (55-70) 29.9 20 to 50 Transmittance
(%) 92 92 88 87

The transparency of acrylic and polycarbonate is almost equivalent to that of crown glass. In addition, the refractive index and the dispersion ratio of acrylic have almost the same values as those of crown glass. The refractive index of the polycarbonate is larger than that of the crown glass, but on the contrary, the Abbe number is small and the dispersion is large.

In addition, acrylic and polycarbonate are plastic, so they are lighter than glass. Compared to the specific gravity of 2.53 of inorganic glass, acrylic is 1.19 and polycarbonate is 1.20. As a result of the impact strength test, acrylic and polycarbonate exhibit a large strength of 5.6 and 92, respectively.

The incident light lens unit 110 is formed of a polycarbonate material and the light output lens unit 120 is formed of an acrylic material. The incident light lens unit 110 has a concave lens surface 111, and the outgoing lens unit 120 Has a convex aspheric lens surface 123, so that chromatic aberration and spherical aberration are corrected, and productivity and manufacturing cost can be reduced.

Here, the incident light lens unit 110 and the light exit lens unit 120 are integrally formed by injection molding.

To this end, a plastic acromatic lens manufacturing apparatus 200 as shown in FIG. 2 is used. The apparatus 200 for manufacturing a plastic acromatic lens according to the present invention includes a lower mold 210, a base mold 220 provided on both sides of the upper portion of the lower mold 210, a first mold 220 disposed on the upper portion of the base mold 220, A coupling shaft 250 connecting the upper mold 230 and the second upper mold 240 to each other and connecting the first upper mold 230 and the second upper mold 240 to each other, (260).

The base mold 220 is formed with a mold corresponding to the light-incoming surface 115 of the incident light lens unit 110. A first material having an optical characteristic of flint glass is injected into an inner space formed by the base mold 220, the lower mold 210 and the first upper mold 230, and the incident light lens unit 110 is injection-molded.

A first mold 231 corresponding to the concave lens surface 111 is formed on the lower portion of the first upper mold 230 and a convex aspheric lens surface 220 of the outgoing lens portion 120 is formed on the lower portion of the second upper mold 240. [ A second mold 241 corresponding to the second mold 123 is formed.

The first upper mold 230 and the second upper mold 240 are provided at both ends of the coupling shaft 250 and are disposed at the upper portion of the base mold 220 selectively by the rotation of the rotary shaft 260. The first upper mold 230 is removed by the first upper mold 230 and then the second upper mold 240 is disposed so that the exit lens unit 120 And injection molding is performed integrally.

Here, since the physical properties of the first material and the second material forming the incident light lens unit 110 and the light output lens unit 120 are different from each other, the cooling rate and the shrinkage ratio may be different. As a result, the plastic acromatic lens 100 in which the incident light lens unit 110 and the light exit lens unit 120 are integrally injection-molded moves the cooling tunnel in which the temperature for each section is set as shown in FIG. 5, Cooling. This can increase the productivity of the product and reduce the defect rate.

A manufacturing process of the apparatus 200 for manufacturing a plastic acromatic lens according to the present invention having such a configuration will be described with reference to FIGS. 2 to 4. FIG.

First, the base mold 220 is prepared and the lower mold 210 is disposed below the base mold 220. The rotating shaft 260 rotates to dispose the first upper mold 230 on the upper portion of the base mold 220. Then, as shown in FIG. 3, the incident light lens unit 110 is first injection-molded by injecting a first material, for example, a polycarbonate resin.

The incident-light lens unit 110 functions as a flint glass in which the concave lens surface 111 is formed. A coupling protrusion 113 is provided at a lower portion of the incident light lens unit 110 to be coupled to a support frame (not shown) when used as a headlight.

When the injection molding of the incident light lens unit 110 is completed, the rotation shaft 260 is rotated and the engagement shaft 250 is moved so that the positions of the first upper mold 230 and the second upper mold 240 are switched. At this time, the coupling shaft 250 can be moved up and down as the case may be.

4, the second upper mold 240 is disposed on the base metal mold 220, and the second material, for example, acrylic resin is injected, Injection molding is carried out integrally on the upper part.

Then, the second upper mold 240, the base mold 220 and the lower mold 210 are separated, and the plastic acromatic lens 100, which has been manufactured, is gradually moved to the cooling tunnel of FIG.

The plastic acromatic lens of the present invention thus completed has the optical characteristics of the achromatic lens formed of the flint glass and the crown glass, and the chromatic aberration can be corrected by providing the concave lens surface and the convex aspheric lens surface. In addition, it is possible to reinforce the stiffness which has been raised as a problem of the conventional plastic lens, and to minimize the sulfur change.

6 and 7 illustrate another manufacturing process of the plastic acromatic lens of the present invention. In the apparatus for manufacturing a plastic lens according to the preferred embodiment of the present invention, the incident light lens unit and the light output lens unit are integrally injection molded.

On the other hand, in the manufacturing process of the acromatic lens according to another embodiment, the incident light lens unit 110a and the light-outgoing lens unit 120a are separately manufactured by separate molds. The boundary region between the thus prepared incident light lens portion 110a and the light-outgoing lens portion 120a is manufactured by bonding or bonding the adhesive 300 as shown in Fig. At this time, the bonding or bonding method may be a plastic welding machine or an adhesive.

The embodiments of the plastic acromatic lens and the apparatus for manufacturing the same of the present invention described above are merely illustrative and those skilled in the art will appreciate that various modifications and equivalent embodiments are possible without departing from the scope of the present invention. You will know the point. Therefore, it is to be understood that the present invention is not limited to the above-described embodiments. Accordingly, the true scope of the present invention should be determined by the technical idea of the appended claims. It is also to be understood that the invention includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims.

100: plastic acromatic lens 110: incident light lens part
111: concave lens surface 113: engaging projection
115: incoming surface 120: outgoing lens portion
123: convex aspheric lens surface
200: Apparatus for manufacturing plastic acromatic lenses
210: lower mold 220: base mold
230: first upper mold 240: second upper mold
250: coupling shaft 260: rotary shaft

Claims

An incident light lens unit having a concave lens surface on which a light is incident and having a concave lens surface on which light is emitted and formed of a first material having optical characteristics corresponding to the flint glass;
And an outgoing lens part formed of a second material having a convex aspherical lens surface coupled to the concave lens surface of the incident light lens part and having a convex aspherical surface to which light is emitted and having an optical characteristic corresponding to the crown glass,
Wherein the light incident lens section and the light exit lens section are integrally formed by injection molding.

The method according to claim 1,
Wherein the first material is polycarbonate and the second material is acrylic (PMMA).

A base mold serving as a center of the mold;
A lower mold coupled to a lower portion of the base mold;
A first upper mold disposed on the base mold and having a first mold corresponding to the concave lens;
A second upper mold disposed on the base mold and having a second mold corresponding to the convex lens;
A coupling shaft coupling the first upper mold and the second upper mold to each other;
And a rotation shaft for rotating the coupling shaft to sequentially dispose the first upper mold or the second upper mold on the upper side of the base mold,
After the base mold and the lower mold are assembled, the first upper mold is disposed on the upper portion of the base mold, and a first material having optical characteristics corresponding to the flint glass is supplied to the injection mold,
The rotation shaft is rotated so that the second upper mold is disposed on the upper portion of the incident light lens unit and then the second material having optical characteristics corresponding to the crown glass is supplied and the outgoing lens unit is integrally injection molded into the incident light lens unit Characterized in that the device is made of a plastic acromatic lens.

The method of claim 3,
Further comprising a cooling tunnel in which a temperature of each section is set to be different, and a plastic acromatic lens integrally injection-molded into the incident light lens unit is gradually moved and a shrinkage ratio is reinforced.

An incident light lens unit having a concave lens surface on which a light is incident and having a concave lens surface on which light is emitted and formed of a first material having optical characteristics corresponding to the flint glass;
And an outgoing lens part formed of a second material having a convex aspherical lens surface coupled to the concave lens surface of the incident light lens part and having a convex aspherical surface to which light is emitted and having an optical characteristic corresponding to the crown glass,
Wherein the light incident lens section and the light exit lens section are independently manufactured by injection molding, and then the light exit lens section is joined or bonded to the upper part of the incident light lens section.

6. The method of claim 5,
Wherein the first material is polycarbonate and the second material is acrylic (PMMA).