Patent Application
20150251329
This application claims the benefit of Chinese Patent Application No. 201410080736.4 filed on Mar. 6, 2014 in the State Intellectual Property Office of China, the whole disclosure of which is incorporated herein by reference.
1. Field of the Invention
The present disclosure relates to a technical field of punching technique, more particularly, to a punching device for punching network nodes on a mold insert and a method of punching network nodes by using the same.
2. Description of the Related Art
Thin film transistor liquid crystal display (TFT-LCD) technique has become very mature, and is applied from a small size screen of mobile phone to a large size screen of television.
A backlight module of a LCD panel includes a light source, a reflection plate, a light guide plate, a diffusion plate, a prism sheet and an optical sheet, or the like. Major techniques of the LCD panel are focused on optical design of the liquid guide plate, mold design and manufacturing, and precision injection molding technology. One of the most crucial requirements for the light guide plate is to improve brilliance and to evenly distribute light rays. Therefore, property of the light guide plate is directly correlated to a yield of the entire backlight module.
Currently, mainstream technologies of the light guide plate include a printing technique and a non-printing technique, wherein the former is to evenly distribute printing materials of high light scattering substance onto a bottom surface of the light guide plate, while the latter is to form V-shaped microgrooves by using a precision mold insert, and then to manufacture the light guide plate complying with optical characteristics by means of a manufacturing mode of injection molding.
High precision light guide plate requires accurate V-shaped grooves having an identical depth, an identical pitch between adjacent grooves, and smooth surfaces of the V-shaped grooves, and so on.
One existing technique employs driving a tool bit with air pressure and injecting it onto the mold insert, so as to form cavities (i.e., network node). It is not easy to adjust the air pressure, so that hole diameters of the formed cavities and tolerance of their depths would dramatically change. This has a relatively large effect on the yield of the light guide plate. In addition, the spacing of the bit and the mold insert cannot be adjusted, and thus this demands the surface of the mold insert has a relatively high flatness. Slight change of the surface height will produce a relatively large effect on the depth of the network nodes.
In order to eliminate the above or other technical problems in the prior art, the present disclosure provides a punching device for punching network nodes on a mold insert, which at least solves the technical problem that a punching force of the existing punching device for mold insert is not easy to adjust, resulting in large change of the hole diameters of the network nodes and the depth tolerance.
In accordance with one aspect of the present invention, it provides a punching device for punching network nodes on a mold insert, comprising:
a first horizontal guide rail;
a mounting seat, installed on the first horizontal guide rail and horizontally movable along the first horizontal guide rail;
a first driver, installed on the first horizontal guide rail and connected with the mounting seat by a first driving mechanism;
a punching mechanism, installed on the mounting seat;
a laser distance meter, installed on the mounting seat;
a host computer, electrically connected with both the punching mechanism and the first driver;
a displacement operation controller, communicated with both the laser distance meter and the host computer; and
a work platform, for carrying the mold insert and located beneath the punching mechanism,
wherein the laser distance meter is configured to measure at least one of depth and hole diameters of the formed network nodes, spacing between the network nodes, and flatness of the mold insert, and the displacement operation controller derives an appropriate value of electrical current from measurement results of the laser distance meter and sends the value of electrical current to the host computer, and the host computer supplies electricity to the electromagnetic mechanism in accordance with the value of electrical current, so as to perform an operation of punching the network nodes on the mold insert.
In accordance with another aspect of the present invention, it provides a method of punching network nodes on a mold insert using a punching device according to claim 1, comprising the following steps:
S1: placing the mold insert on a work platform of the punching device;
S2: setting a value of electrical current supplied to an electromagnetic mechanism within a punching mechanism in accordance with depths of network nodes and hole diameters thereof;
S3: starting the punching mechanism, and sending the set value of the electrical current to the electromagnetic mechanism by a host computer, so that the electromagnetic mechanism generates a corresponding repulsive force, and under the action of such repulsive force, the plunger within the punching mechanism is pushed and in turn it pushes a tool bit so as to perform a network node punching operation;
S4: performing measurement by means of a laser distance meter during the network node punching operation, and using a displacement operation controller to calculate a tolerance value of displacement from measurement results of the laser distance meter and converting it into a tolerance value of the electrical current, and adjusting a value of the electrical current supplied to the electromagnetic mechanism by means of the host computer in accordance with the tolerance value of the electrical current;
S5: during the punching process of the network nodes on the mold insert, controlling the first driver by the host computer so as to drive the mounting seat and horizontally move it along the first horizontal guide rail in a first direction, so that the tool bit horizontally moves in the first direction; and controlling the second driver so as to drive the work platform and horizontally move it along the second horizontal guide rail in a second direction perpendicular to the first direction, so that the mold insert horizontally moves in the second direction, thereby performing the punching operations of the plurality of network nodes on the surface of the mold insert.
The above and other features of the present invention will become more apparent by describing in detail exemplary embodiments thereof with reference to the accompanying drawings, in which:
In the following detailed description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the disclosed embodiments. It will be apparent, however, that one or more embodiments may be practiced without these specific details. In other instances, well-known structures and devices are schematically shown in order to simplify the drawing.
Specific embodiments of the present invention will be described in detail with reference to the accompanying drawings. The following embodiments are used to explain the present invention, but not limiting to the scope of the present invention.
As shown in
A triangulation technique is used by the laser distance meter 11, to measure depths and hole diameters of the formed network nodes on the mold insert, spacing between adjacent network nodes, and flatness of the mold insert. It should be noted that the laser distance meter 11 can only measure at least one of the thicknesses and hole diameters of the formed network nodes, spacing between adjacent network nodes, and flatness of the mold insert. The displacement operation controller converts measurement results such as displacement information fed back from the laser distance meter 11 into a suitable value of electrical current, and sends it to the host computer. Then, the host computer transmits it into the punching mechanism to perform a dotting operation or a network node punching operation in accordance with the calculated value of electrical current. The present invention accurately measures in real-time the depth of the network node, the hole diameter, the flatness of the surface of the mold insert and the spacing between adjacent network nodes by means of the laser distance meter. In this way, it is possible to adjust in real-time the punching force of the network node outputted from the punching mechanism and the movement position of the punching mechanism during the punching process. Therefore, the hole diameter and the depth of the network node and the uniformity thereof are accurately controlled, and further the tolerance of the depth and the hole diameter of the network node can be reduced and the yield of the light guide plate can be improved.
As shown in
When the power source is switched on, the electromagnetic mechanism 4 is supplied with electricity to generate the magnetic force for pushing the plunger 3. The plunger 3 pushes the tool bit 2 downwardly, so as to punch the mold insert and to form the desired cavities (i.e., the network nodes). After the punching of the cavity, under the action of the return spring 5, the bit 2 is restored by the driving of the plunger 3, in order to perform next punching of another cavity. During the punching process, a value of the electrical current supplied to the electromagnetic mechanism 4 (the electricity supplied to the electromagnetic mechanism 4) is adjusted by the host computer as required and in accordance with the practical condition. Further, the magnetic force generated by the electromagnetic mechanism 4 can be adjusted, thereby obtaining the desired hole diameter and the depth of the cavity, reducing the tolerance of the depth, and improving the yield of the light guide plate.
The upper portion 1a of the housing has a larger diameter than that of the lower portion 1b of the housing, which produces the following effects: on one hand, positioning of the return spring 5; and on the other hand, the punching action of the plunger 3 is guided due to the less diameter of the lower portion 1b, in order to avoid colliding of the plunger 3 with the housing 1 caused by a shifting movement thereof.
The electromagnetic mechanism 4 includes an upper part 4a of the electromagnetic mechanism and a lower part 4b of the electromagnetic mechanism, wherein the upper part 4a is connected with the host computer via the cable 6, and the lower part 4b is connected with the upper end of the plunger 3. Herein, both the upper part 4a and the lower part 4b are made of electromagnet and windings wound around an exterior of the electromagnet. When the power source is switched on, the upper part 4a and the lower part 4b of the electromagnetic mechanism generate repulsive force therebetween. Such repulsive force pushes the plunger 3 and then in turn the tool bit 2 downwardly, so as to punch the mold insert for forming the desired network nodes. As used herein, the electromagnetic mechanism is used as a drive mechanism for performing the punching operation. During the punching process, the voltage of the power source can be adjusted as desired and in accordance with the actual condition, and the magnetic force of the electromagnetic mechanism can be adjusted as well, thereby improving controllability and punching accuracy of the overall punching mechanism.
The housing 1 is made of diamagnetic materials having low friction coefficient, and would not have any effect on the magnetic field of the electromagnetic mechanism 4. Furthermore, there is a small friction force between the plunger 3 and the housing 1 during the movement of the plunger 3, because when the plunger 3 is performing the punching operation, the plunger 3 is likely to slightly collide with the lower portion 1b of the housing. Therefore, the housing having the lower friction coefficient ensures that the plunger 3 would not be hindered during the movement. In one example, the housing 1 is made of PTEF material, or the inside of the housing 1 is formed with a PTEF material layer.
In order to facilitate replacement of the plunger 3, the punching mechanism of the present embodiment further includes a connecting joint 7, which is fixed onto the lower part 4b of the electromagnetic mechanism and held stationary with respect to the lower part 4b, and threaded with the upper end of the plunger 3.
Since a plurality of network nodes are distributed on the surface of the mold insert, in order to move the mold insert, as shown in
The work platform 12 is made of permanent magnetic materials, and is used to fix the mold insert by an attractive force therebetween when it is placed on the platform 12. In addition, as shown in
The punching device for punching network nodes on the mold insert of the present embodiment further includes a second driver electrically connected with and controlled by the host driver. The second driver is installed on the second horizontal guide rail 13 and is connected with the work platform 12 by a second driving mechanism, so as to drive the work platform 12 to horizontally move along the Y direction on the second horizontal guide rail 13.
In order to automatically adjust the distance between the tool bit 2 and the mold insert, the punching device for punching network nodes on the mold insert of the present embodiment is provided with a vertical guide rail 15 on the mounting seat 9. The housing 1 of the punching mechanism is mounted on the vertical guide rail 15 and is capable of vertically moving along the vertical guide rail 15. Further, a third driver is installed on the mounting seat 9, which is connected with the housing 1 by a third driving mechanism, so as to drive the housing 1 to vertically move along the vertical guide rail 15 automatically. In one example, the third driver is electrically connected with the host computer, so as to control the third driver by the host computer.
In order to finely adjust the position of the tool bit 2 in the vertical direction, the housing 1 of the punching mechanism of the present embodiment is vertically installed on the mounting seat 9 by means of a fine adjustment knob 10. Such fine adjustment knob 10 can finely adjust the position of the housing 1 in the vertical direction, that is, the position of the tool bit 2 in the vertical direction, and further adjust the distance between the tool bit 2 and the mold insert on the work platform 12.
The specific working procedure of the punching device for punching network nodes on the mold insert in accordance with one embodiment of the present invention is as follows, in combination with
Step S1—firstly placing the mold insert on the work platform 12, and aligning the square edges of the mold insert with the two stops 14.
Step S2—setting an appropriate value of the electrical current supplied to the electromagnetic mechanism 4 in accordance with the depths of the actual network nodes and the hole diameters thereof.
The host computer firstly controls the first and second drivers so as to horizontally adjust the relative position of the tool bit 2 and the mold insert, so that the tool bit 2 arrives at the position of dotting or performing network node punching operation. Then, the host computer controls the third driver to adjust the height of the tool bit 2, so as to coarsely adjust the distance between the tool bit 2 and the mold insert. Finally, the fine adjustment knob 10 is used to finely adjust the distance between the tool bit 2 and the mold insert. In accordance with a relationship of the current value of the electromagnetic mechanism with the distance between the tool bit and the mold insert, it is possible to find out a suitable value of the electrical current supplied to the electromagnetic mechanism 4 by measuring the distance between the tool bit 2 and the mold insert.
Step S3—starting the punching mechanism, and sending the predetermined value of the electrical current to the electromagnetic mechanism 4 by the host computer, so that the electromagnetic mechanism 4 generates a corresponding repulsive force, and under the action of such repulsive force, the plunger 3 is pushed and in turn the tool bit 2 is pushed so as to perform the dotting operation or the network node punching operation.
Step S4—performing triangulation by means of the laser distance meter 11 during the dotting, measuring the flatness of the mold insert, the spacing between the network nodes, the depths of the network nodes and the hole diameters of the network nodes, and sending them to the displacement operation controller; and confirming measurement results from the laser distance meter 11 via the displacement operation controller and converting them, so as to determine whether to adjust the value of the electrical current supplied to the electromagnetic mechanism 4.
It should be understood that when the surface of the mold insert is sufficiently flat or the flatness thereof complies with the relevant requirement (i.e., within the acceptable tolerance range), it is not necessary to adjust the electrical current value of the electromagnetic mechanism 4; and when the surface of the mold insert is not flat or the flatness thereof does not comply with the relevant requirement, the displacement operation controller calculates a tolerance value of the displacement and converts it into a tolerance value of the electrical current, and the host computer increases or decreases the current value of the electromagnetic mechanism 4 in response to the tolerance value of the electrical current, so as to ensure the depths and the hole diameters of the network nodes on the whole mold insert to be consistent with each other, and the uniformity of the network nodes on the whole mold insert may be acquired.
During the dotting, since the surface of the mold insert cannot be absolutely flat, when a height difference is detected between the current distance between the mold insert and the tool bit and an initial distance between the mold insert and the tool bit, the electrical current value of the electromagnetic mechanism should be adjusted accordingly. If the detected height difference is positive, then it indicates the distance between the mold insert and the tool bit is larger than the initial distance, and it is necessary to increase the electrical current value of the electromagnetic mechanism 4. Otherwise, when the detected height difference is negative, the electrical current value of the electromagnetic mechanism 4 shall be reduced.
Step S5—during the punching process of the network nodes on the mold insert, controlling the first driver by the host computer so as to drive the mounting seat 9 and horizontally move it along the first horizontal guide rail in the X axis direction, so that the tool bit 2 horizontally moves in the X axis direction; and controlling the second driver by the host computer so as to drive the work platform 12 and horizontally move it along the second horizontal guide rail 13 in the Y axis direction, so that the work platform 12 horizontally moves in the Y axis direction, thereby performing the punching operations of the plurality of network nodes on the surface of the mold insert.
Concerning the above, the punching device for punching network nodes on the mold insert of embodiments of the present invention utilizes the laser distance meter to accurately measure the depths and the hole diameters of the network nodes, the flatness of the surface of the mold insert and the spacing between the network nodes in real-time. Therefore, it is capable of adjusting in real-time the punching force of the network nodes of the punching mechanism and the moving position thereof during the punching process, thereby achieving the accurate control of the hole diameters, the depths and the uniformity of the network nodes. Further, the tolerances of the depths and the hole diameters of the network nodes can be reduced, and the yield of the light guide plate can be improved. Further, the electromagnetic mechanism is served as the drive mechanism for punching the network nodes on the mold insert. During the punching operation, the voltage of the power source can be adjusted as needed and depending on the actual conditions, and then the magnetic force of the electromagnetic mechanism can be adjusted, thereby improving the controllability of the whole punching mechanism and improving the punching accuracy. The punching device of embodiments of the present invention has a high automation on the whole, may reduce artificial error and improve the working efficiency.
Although several exemplary embodiments have been shown and described, the present invention is not limited to those and it would be appreciated by those skilled in the art that various changes or modifications may be made in these embodiments without departing from the principles and spirit of the disclosure. These changes or modifications also fall within the scope of the present invention. The scope of the present invention is defined by the claims and their equivalents.
| Number | Date | Country | Kind |
|---|---|---|---|
| 201410080736.4 | Mar 2014 | CN | national |
