CN114179260B

CN114179260B - Method for manufacturing light guide plate forming die

Info

Publication number: CN114179260B
Application number: CN202111370182.8A
Authority: CN
Inventors: 邱良芳; 史常青; 夏启
Original assignee: Nano Precision Suzhou Co Ltd
Current assignee: Nano Precision Suzhou Co Ltd
Priority date: 2021-11-18
Filing date: 2021-11-18
Publication date: 2023-03-24
Anticipated expiration: 2041-11-18
Also published as: CN114179260A

Abstract

The invention provides a manufacturing method of a light guide plate forming mold, which comprises the steps of cutting the surface of a template by using a cutting effective surface of a cutter to form a first micro groove and a second micro groove which are connected, cutting the joint of the first micro groove and the second micro groove by using the cutting effective surface of the cutter to form a buffer surface, and cutting the joint of the buffer surface and the first micro groove by using the cutting effective surface of the cutter to remove burrs. The manufacturing method of the light guide plate forming mold provided by the invention has the advantages of lower production cost and simpler manufacturing process.

Description

Method for manufacturing light guide plate forming die

Technical Field

The present invention relates to a manufacturing method, and more particularly, to a manufacturing method of a mold for forming a light guide plate.

Background

At present, most of electronic devices utilize a flat display module to display images, and the technology of the liquid crystal display module is well-known and popular. However, since the display panel of the lcd module cannot emit light, a backlight module is disposed below the display panel to provide light required for displaying images. The backlight module can be mainly divided into an edge type backlight module and a direct type backlight module. The backlight module utilizes the light guide plate to guide the light rays emitted by the light source arranged on the light incident surface of the light guide plate to the light emergent surface of the light guide plate so as to form a uniform surface light source.

Generally, optical microstructures are formed on the surface of the light guide plate to improve the uniformity and brightness of the light emitted from the light guide plate. The light guide plate and the optical microstructure thereof manufactured by the injection molding process are a common manufacturing method, and have the advantages of high and stable transcription rate of the optical microstructure, so the light guide plate is particularly suitable for special optical microstructures with complex shapes. In order to improve the utilization rate of the product and save the cost, the surface structure of the light guide plate forming mold (such as a core insert) is generally processed by surface reduction. However, during the step down machining, burr abnormalities are liable to occur at the cutting edge.

Disclosure of Invention

The invention provides a manufacturing method of a light guide plate forming mold, which has lower production cost and simpler manufacturing process.

Other objects and advantages of the present invention will be further understood from the technical features disclosed in the present invention.

In order to achieve one or a part of or all of the above or other objects, an embodiment of the invention provides a method for manufacturing a light guide plate forming mold. The manufacturing method of the light guide plate forming mold comprises the steps of cutting the surface of the template by using the cutting effective surface of the cutter to form a first micro groove and a second micro groove, cutting the joint of the first micro groove and the second micro groove by using the cutting effective surface of the cutter to form a buffer surface, and cutting the joint of the buffer surface and the first micro groove by using the cutting effective surface of the cutter to remove burrs. The first micro-groove is connected with the second micro-groove.

In view of the above, in the method for manufacturing a light guide plate molding die according to an embodiment of the present invention, a plurality of machining processes are performed using different regions of the cutting effective surface of the same tool, for example: the cutting process of a plurality of micro grooves, the wave crest removing process of the joints of the micro grooves and the burr removing process can effectively save the cutter replacing time among different processes, thereby improving the productivity. On the other hand, since the burr can be removed without using an additional cutter, the cost advantage of the general light guide plate forming mold can be maintained for the surface reduction processing.

Drawings

Fig. 1A to 1D are schematic cross-sectional views illustrating a manufacturing process of a light guide plate forming mold according to an embodiment of the invention.

List of reference numerals

100: form

100s surface

150bs bottom surface

150g, 150g1, 150g2 micro grooves

151 at the joint

151c buffer joint face

200 cutting tool

200CS central convex surface

200S cutting effective surface

200SS1 first side effective surface

200SS2 second side effective surface

B1, B2: burr

C1, C2 symmetry center

CP1, CP2: junction

d is distance

D1, D2 directions

DT1 first depth

R is radius of curvature

S1 first offset

S2 second offset

W1: first width.

Detailed Description

The foregoing and other technical and scientific aspects, features and utilities of the present invention will be apparent from the following detailed description of a preferred embodiment when read in conjunction with the accompanying drawings. Directional terms as referred to in the following examples, for example: up, down, left, right, front or rear, etc., are simply directions with reference to the drawings. Accordingly, the directional terminology is used for purposes of illustration and is in no way limiting.

Fig. 1A to 1D are schematic cross-sectional views illustrating a manufacturing process of a light guide plate forming mold according to an embodiment of the invention. Referring to fig. 1A and 1B, first, a tool 200 is used to cut the surface 100s of the template 100 to form a plurality of micro-grooves 150g, for example, the micro-grooves 150g are cut along a direction perpendicular to the first direction D1 and the second direction D2 (a cutting path, a moving path of the most pointed end of the tool 200), that is, the micro-grooves 150g extend along a direction perpendicular to the first direction D1 and the second direction D2. In detail, the tool 200 has a cutting effective surface 200S for cutting the micro grooves 150g, and a cross-sectional profile (e.g., a forward projection profile on a drawing plane, i.e., a forward projection profile on a plane parallel to a first direction D1 and a second direction D2) of the micro grooves 150g is substantially the same as the cross-sectional profile of the cutting effective surface 200S, the first direction D1 is, for example, parallel to the surface 100S, and the second direction is, for example, perpendicular to the surface 100S.

For example, in the present embodiment, the mold plate 100 having the micro grooves 150g can be used as a molding mold of a light guide plate, such as an imprint mold (imprint mold). In another embodiment, the mold plate 100 and another upper mold plate, not shown, disposed opposite to each other may also be used as a molding mold of the light guide plate. More specifically, the mold plate 100 and the upper mold plate define a mold cavity for molding the light guide plate. That is, the molding die formed by the mold plate 100 and the upper mold plate may be an injection molding (injection molding) die.

Of particular note, any two adjacent micro-grooves 150g are connected to one another to form a junction 151 having a peak. Since the wave crests of the micro grooves 150g are easily burred during the manufacturing and production process, which affects the molding quality of the light guide plate, a wave crest removing process is required to be performed on the connecting portions 151 of the micro grooves 150 g.

Further, in the present embodiment, the cutting effective surface 200S of the tool 200 can be divided into a central convex surface 200CS and a first side effective surface 200SS1 and a second side effective surface 200SS2 (corresponding to the left side and the right side of the cutting path, for example) connected to the central convex surface 200CS and opposite to each other. For example, the central convex surface 200CS, the first side effective surface 200SS1 and the second side effective surface 200SS2 may have the same curvature radius R or the difference of the curvature radii is less than 5% of the curvature radius of the central convex surface 200CS, so that the optical quality of the optical microstructure manufactured by using the micro grooves 150g can be improved. That is, the cross-sectional profile (e.g., the orthographic projection profile on the drawing plane of fig. 1A) of the cutting effective surface 200S of the present embodiment is a perfect circular arc. Preferably, the curvature radius R may be between 20 μm and 50 μm.

Next, the joint 151 of any two adjacent micro grooves 150g (e.g., the first micro groove 150g1 and the second micro groove 150g 2) is cut by the cutting effective surface 200S of the tool 200 to form a relief surface 151c. Specifically, the step of forming the buffer surface 151c includes: the meeting 151 of the micro-grooves 150g is cut by the convex central surface 200CS of the cutter 200. For example, the micro groove 150g has a first depth DT1 along the second direction D2. The first depth DT1 is, for example, the maximum distance between the bottom surface 150bs cut by the central convex surface 200CS of the tool 200 in the micro groove 150g and the surface 100s of the template 100 along the second direction D2. Preferably, the maximum distance between the buffer surface 151c and the bottom surface 150bs along the second direction D2 (i.e., the distance D in fig. 1B) is 0.85 times to 0.95 times the first depth DT1.

After the formation of the buffer surface 151c is completed, burrs may exist at the junctions between the buffer surfaces 151c and the adjacent micro grooves 150 g. For example, in the present embodiment, the junction CP1 of the buffer surface 151c and the first micro-groove 150g1 forms the burr B1, and the junction CP2 of the buffer surface 151c and the second micro-groove 150g2 forms the burr B2, but the present invention is not limited thereto. In other embodiments, if the contact portion 151 is cut at a portion where the central convex surface 200CS is deviated from the symmetrical center thereof, the burr may be formed only on one side of the relief surface 151c.

Referring to fig. 1C, in order to remove the burr, the junction between the buffer surface 151C and the micro-groove may be cut by using the cutting effective surface 200S of the tool 200. For example, the step of removing the burr may comprise: the junction CP1 between the relief surface 151c and the first micro groove 150g1 is cut by the first side effective surface 200SS1 of the cutting effective surface 200S of the tool 200. Before cutting, the tool 200 is moved to a target position, and the first side effective surface 200SS1 of the tool 200 faces the burr B1.

In the present embodiment, the target position is, for example, a position of a symmetry center C1 of the central convex surface 200CS of the tool 200 (e.g., at the most tip end of the tool 200). For example, the bottom surface 150bs of the first micro-groove 150g1 cut by the central convex surface 200CS of the cutting tool 200 has a center of symmetry C2, and the center of symmetry C1 has a first offset S1 and a second offset S2 in the first direction D1 and the second direction D2, respectively, with respect to the center of symmetry C2 of the bottom surface 150 bs.

Specifically, the target position of the tool 200 is determined by the radius of curvature R (shown in fig. 1A) of the cutting effective surface 200S of the tool 200. That is, in the present embodiment, the method of manufacturing the light guide plate molding die may further include: before the burr removing step, the curvature radius of the tool 200 is calculated, and the first offset amount S1 and the second offset amount S2 are determined according to the calculated curvature radius. In the present embodiment, the radius of curvature of the tool 200 can be calculated by measuring the radius of curvature of the micro-grooves 150g cut on the template 100. For example: the radius of curvature of the tool 200 can be calculated by measuring the micro-grooves cut by the tool 200 during the trial cutting stage or measuring the micro-grooves 150g cut during the main process. Thus, the first offset S1 and the second offset S2 can be accurately calculated, so as to prevent the buffer surface 151c from being damaged when the burr is removed, and thus the optical quality of the optical microstructure manufactured by using the micro grooves 150g is damaged. Specifically, the deburring step of the present invention maintains the integrity of the buffer surface 151c, and more specifically, the deburring step is not a chamfering step. For example, the width of the buffer surface 151c in the first direction D1 before the deburring step is performed is the same as or within 5% of the width of the buffer surface 151c in the first direction D1 after the deburring step is completed. Thus, complicated processing calculation or repeated processing can be avoided, and the optical effect of the finished product can be maintained.

For example, the micro-groove 150g also has a first width W1 along a first direction D1 (e.g., a direction perpendicular to the cutting direction and parallel to the surface 100 s), wherein the first width W1 is greater than the first depth DT1. The first width W1 is, for example, the distance between two buffer surfaces 151c connected to the micro groove 150g in the first direction D1. The target position of the tool 200 may have a first offset S1 with respect to the center of symmetry C2 of the bottom surface 150bs of the micro groove 150g that is less than half the first width W1 and a second offset S2 that is less than the first depth DT1. Accordingly, a better burr removing effect can be obtained.

It should be noted that, in the manufacturing method of the light guide plate forming mold of the present disclosure, the same tool 200 is used to cut the micro grooves 150g, cut the wave crests between any two adjacent micro grooves 150g, and remove the burrs between the buffer surfaces 151c and the micro grooves 150g, so that the tool changing time between different processes can be saved, the manufacturing accuracy can be improved, and the damage to the surfaces of the micro grooves caused by the general brush removing step can be avoided. The convenience of the manufacturing process can be improved, and the productivity of the light guide plate forming mold can be effectively improved.

In this embodiment, the step of removing the burr may further include: the junction CP2 of the relief surface 151c and the second micro groove 150g2 is cut by the second side effective surface 200SS2 of the cutting effective surface 200S of the tool 200, as shown in fig. 1D. Since the process of removing the burr B2 is similar to the process of removing the burr B1, the detailed description is given in the related paragraphs, which are not repeated herein.

As described above, in the method for manufacturing a light guide plate molding die according to an embodiment of the present invention, a plurality of machining processes are performed using different regions of the cutting effective surface of the same tool, for example: the cutting process of a plurality of micro grooves, the wave crest removing process of the joints of the micro grooves and the burr removing process can effectively save the cutter replacing time among different processes, thereby improving the productivity. On the other hand, since the burr can be removed without using an additional cutter, the cost advantage of the general light guide plate forming mold can be maintained for the surface reduction processing.

The above description is only a preferred embodiment of the present invention, and the scope of the present invention should not be limited thereby, and all the simple equivalent changes and modifications made according to the claims and the content of the specification should be included in the scope of the present invention. It is not necessary for any embodiment or claim of the invention to achieve all of the objects or advantages or features disclosed herein. Furthermore, the abstract and the title of the specification are provided to assist the retrieval of patent documents and are not intended to limit the scope of the invention. Furthermore, the terms "first", "second", and the like in the description or the claims are used only for naming elements (elements) or distinguishing different embodiments or ranges, and are not used for limiting the upper limit or the lower limit on the number of elements.

Claims

1. A method for manufacturing a light guide plate forming mold is characterized by comprising the following steps:

cutting on a surface of a template with a cutter to form a first micro groove and a second micro groove, the first micro groove being connected with the second micro groove, wherein the cutter has a cutting effective surface cutting the first micro groove and the second micro groove, the cutting effective surface is divided into a central convex surface and a first side effective surface and a second side effective surface connecting the central convex surface and opposite to each other, the central convex surface, the first side effective surface and the second side effective surface have a radius of curvature, the first micro groove has a first width along a first direction and a first depth along a second direction, the first micro groove has a bottom surface cut by the central convex surface;

cutting the joint of the first micro groove and the second micro groove by using the cutting effective surface of the cutter to form a buffer joint surface, wherein a burr is arranged at the joint of the buffer joint surface and the first micro groove and is positioned between the buffer joint surface and the bottom surface of the first micro groove; and

cutting the joint with the first or second side active face of the tool to remove the burr, the removing step of the burr comprising: and moving the cutter to a target position, enabling the first side of the cutter to effectively face towards the burr, enabling the symmetry center of the central convex surface of the cutter to respectively have a first offset and a second offset in the first direction and the second direction relative to the symmetry center of the bottom surface of the first micro-groove, calculating the curvature radius of the cutter, and determining the first offset and the second offset according to the curvature radius, wherein the first offset is smaller than half of the first width, and the second offset is smaller than the first depth.

2. The method for manufacturing a mold for molding a light guide plate according to claim 1, wherein the step of forming the relief surfaces comprises: cutting the junction of the first and second micro-grooves with the central land of the cutter.

3. The method of manufacturing a light guide plate molding die according to claim 1, wherein the step of removing the burr includes: cutting the joint with the first side of the tool effective face.

4. The method for manufacturing a light guide plate molding die according to claim 1, wherein another burr is present at another junction of the buffer surface and the second micro groove after the buffer surface is formed, and the method for manufacturing a molding die further comprises: cutting the other junction with the second side of the tool effective to remove the other burr.

5. The method of claim 1, wherein the first width is greater than the first depth.

6. The method as claimed in claim 1, wherein the distance between the buffer surface and the bottom surface is 0.85 to 0.95 times the first depth.

7. The method of claim 1, wherein the radius of curvature is between 20 μm and 50 μm.