KR101849538B1 - Mold for a light guide plate, apparatus for forming dimples onto the a light guide plate, and a light guide plate - Google Patents

Abstract

BACKGROUND OF THE INVENTION Field of the Invention [0001] The present invention relates to an elasticity adjusting device for a pattern processing machine for producing a light guide plate, and more particularly, to an elasticity adjusting device for a pattern processing machine for producing a light guide plate using magnetic force.
A patterning head according to the present invention includes: a piezoelectric element which vibrates up and down according to an applied voltage; An elastic member holder vibrating up and down according to the vibration of the piezoelectric element and having a hole formed at a lower end thereof; The upper end being located inside the elastic member holder and the lower end being inserted into the hole formed at the lower end of the elastic member holder and projecting out of the elastic member holder through the hole; And a plurality of dimples mounted on the die holder to form a plurality of dimples on the mold core, wherein the elastic member holder comprises: a first permanent magnet supporting an upper surface of the bite holder; A second permanent magnet having a repulsive force with respect to the first permanent magnet and a pressure regulating means for regulating the pressure applied to the upper surface of the bite holder by adjusting the vertical position of the second permanent magnet .

Description

TECHNICAL FIELD [0001] The present invention relates to a light guide plate mold, a light guide plate mold, a light guide plate, and a light guide plate,

The present invention relates to a patterning machine for a light guide plate mold, a light guide plate mold for manufacturing the same, and a light guide plate manufactured using the same. More specifically, the present invention relates to a light guide plate mold having a small number of dots, To a light guide plate having a small number of dots.

The light guide plate is a device for scattering light incident from a light source such as a light emitting diode (LED) located on a side and discharging the light to the front side. The light guide plate is a backlight unit (BLU: back) which plays a key role in a liquid crystal display light unit and provide uniform illumination.

The manufacturing method of the light guide plate includes an extrusion method in which the extruded plate is cut to size according to the use, the cut surface is processed like a mirror and then the optical resin is applied and printed on the light emitting surface, and the injection method .

The injection molding method is divided into a method in which an optical pattern is directly injected into a mold, a method in which a stamper engraved with an optical pattern is formed on the outside, and the mold is mounted on the mold. In addition, laser cutting process and inkjet process have a disadvantage that processing time is relatively long. In the process of molding and extracting the product using air, the raw material, polymethyl methacrylate (PMMA) is heated in an aluminum mold There is a vacuum mold (VM) method that produces finished products.

Among these manufacturing methods, a pattern forming die used in an injection molding method or a vacuum mold method is formed by forming a pattern corresponding to a pattern of a light guide plate on the upper surface of a mold core, usually in the form of a dot of an obverse angle. Conventionally, a method using photolithography has been mainly used to form such a dot pattern. However, in the photolithography process, the photoresist is sometimes not washed properly in the cleaning step, and a pattern of a desired shape is not formed, or a pattern can not be reproduced when the pattern is formed. In addition, not only does the process take a long time, but there are also environmental problems due to chemical treatment.

Due to the problem of the photoresist process, recently, a method of forming a pattern on a mold core by using a laser or a bite has been used. However, due to the demand for slimming down the light guide plate to be applied to an ultra-thin liquid crystal display such as a smart phone, the pattern formation method using a laser has problems such as pattern size limitation, burr generation, non- Reproducibility and the like. On the other hand, in the pattern formation method using a byte, it is possible to form a fine pattern and various patterns according to the size and shape of a byte, and the bur size is remarkably smaller than the laser processing method and the reproducibility is also excellent. Despite these advantages, the pattern forming head using the conventional bite has a pattern formation speed of 25 or less per second and an error range of the pattern depth of more than ± 200 nm. In the production of a light guide plate of a size larger than a smartphone, Uneven stripes are formed and appearance defects are generated.

In order to solve such a problem, Korean Patent No. 10-1299974 discloses an apparatus for forming a perforation pattern having a depth of 10 μm or less and an error range of ± 100 nm on the surface of a mold for producing a light guide plate using a piezoelectric element. The device is vertically coaxially aligned with the piezoelectric element 11, the elastic member holder 13, the byte holder 15 and the bite 16, as shown in Figs. This device is configured such that when a current is applied to the piezoelectric element 11, the length of the piezoelectric element 11 instantaneously increases and the elastic member holder 13 located at the lower end, the byte holder 15 and the bite 16 rapidly descend Thereby hitting the surface of the mold and forming a hemispherical hole on the mold surface by blowing.

The elastic member holder 13 is equipped with a spring 144 member for absorbing an impact generated at the time of impact and adjusting the depth of the dimple. The spring member 144 is positioned between the throttle plate 133 and the bite holder 15. The elasticity of the spring member 144 is greatly reduced and the elasticity of the spring member 144 is reduced to strongly support the bite holder 15 and the bite 16 does not retreat when hitting the metal mold, The depth of the perforation increases. On the other hand, when the throttle plate 133 is lifted up to the maximum, the spring member 144 is slightly compressed to increase elasticity, weakly supporting the bite holder 15, and retracted when the bite 16 hits the metal mold , The depth of the piercing hole becomes smaller.

In order for the light guide plate to exhibit uniform and high brightness, the arrangement of the dots formed on the light scattering surface is important. In the case of uniformly forming dots on the surface of the light guide plate, the luminance is bright in the edge region (light incoming portion) close to the light source on the side, and the luminance is decreased in the central portion (large light portion) farther from the light source on the side. (The number of dots per unit area) of the light-incident portion, and the density of the dots is lowered in the light-incident portion.

It is difficult to achieve the brightness and uniformity of light emitted to the front surface of the light guide plate through a single operation due to various factors. After the actual light guide plate is injected through the first manufactured mold, the uniformity and the brightness of the light source are measured, and the dots are further formed by forming additional dots at the portions where the brightness is decreased, thereby increasing the density of the dots. .

If this method is repeated a number of times, the number of dots added at each step increases sharply in the final mold. Due to cost increase of mold manufacturing and densification of dots, there is a gap between the dots, which causes defects.

A problem to be solved by the present invention is to provide a new light guide plate mold capable of exhibiting uniform and high luminance while preventing densification of dots and a method of manufacturing the same.

Another problem to be solved by the present invention is to provide a device for manufacturing a new light guide plate mold which can exhibit uniform and high luminance while preventing densification of dots.

Another problem to be solved by the present invention is to provide a new light guide plate capable of exhibiting uniform and high luminance while preventing densification of dots.

In order to solve the above problems,

The depth of the dimples formed on the surface of the light guide panel mold according to the present invention differs depending on the region and the depth of the dimples formed in the region where the luminance is lower than the depth of the dimples formed in the region with high luminance is large.

'Depth' means depth within the machining error range. And is understood to be substantially within an error range of +/- 0.2 mu m.

The term " the depth of dimples is large " means that the difference between the depth of the dimples in the specific region and the region dimples in the other region exceeds the processing error range.

The term 'high brightness region' means a mold region corresponding to a region having a high brightness when light is emitted from a side surface of a light guide plate by forming dots on the mold at the same depth and at equal intervals. (Mold light incident portion) substantially corresponding to the light guide plate light incident portion.

The term 'low brightness region' means a mold region corresponding to a region having a low brightness when a light guide plate is manufactured by forming dots on the mold at the same depth and at the same interval and then light is emitted from the side. And substantially means the mold region (mold-to-light portion) corresponding to the light guide plate-to-light portion. It is understood that the mold light-shielding portion includes a region between the mold central portion, the edge where the light source is not disposed, and the light source among the light-guide plate light-incident portion.

Though not theoretically limited, by increasing the scattering degree by forming the depth of the dots deeply instead of increasing the density of the dots in the low brightness region in the manufacturing process of the light guide plate, the density of the dots is prevented from being increased in the process of correcting the light guide plate.

In the practice of the present invention, the dimples formed in the low-luminance region have a depth of 2.5 to 10 mu m, preferably 3 to 8 mu m, more preferably 4 to 7 mu m, May have a depth of 1 to 2.4 탆, and preferably a depth of 1.6 to 2.0 탆.

In the practice of the present invention, the depth difference between the dimples formed in the low luminance region and the dimples formed in the high luminance region is 0.5 mu m or more, preferably 1 mu m or more, more preferably 2 mu m or more, Lt; / RTI >

According to one aspect of the present invention, there is provided a patterning head for forming a dimple by striking a surface of a mold with a bite so as to form a light guide plate mold having different depths in each region as described above, And a control unit for forming dimples having different depths according to the data stored using the pattern forming head.

In the present invention, the patterning head may include a piezoelectric element that vibrates up and down according to an applied voltage; An elastic member holder oscillating up and down in accordance with the vibration of the piezoelectric element and having an elastic member for supporting the bite; And a bite that is supported by an elastic member included in the elastic member holder and strikes the mold to form a dimple. The control unit controls the voltage applied to the piezoelectric element or the elasticity of the elastic member according to the stored data. Thereby adjusting the depth of the dimple.

In one embodiment of the present invention, the elastic member may be a spring, and a pressing plate movable up and down is formed on the upper surface of the spring, and the elastic supporting force for supporting the bite can be adjusted by adjusting the position of the pressing plate.

In one embodiment of the present invention, the elastic member may be a pair of magnets in which a repulsive force incorporated in the elastic member holder acts. The lower magnet supports the bite and the upper magnet is spaced apart by the lower magnet and the repulsive force, and the height is adjusted by a height regulating device controlled by the control part.

In a preferred embodiment of the present invention, the height regulating device comprises an extension piece fixed to or contacting the upper magnet and extending to the outside of the elastic member holder, and a motor regulating part for regulating the height of the extension piece in the elastic member holder by the control part . For example, a DC motor, a ball screw motor, a linear motor, or the like may be used as the motor control unit.

In a preferred embodiment of the present invention, a piezoelectric element vibrating up and down according to an applied voltage; An elastic member holder vibrating up and down according to the vibration of the piezoelectric element and having a hole formed at a lower end thereof; The upper end being located inside the elastic member holder and the lower end being inserted into the hole formed at the lower end of the elastic member holder and projecting out of the elastic member holder through the hole; A bite mounted on the bite holder to form a plurality of dimples on the mold surface; A first magnet for supporting an upper surface of the bite holder inside the elastic member holder; And a second magnet located above the first magnet and having a repulsive force with respect to the first magnet; a data storage section about a depth of a dimple to be processed for each region of the mold; Accordingly, there is provided a light guide plate mold pattern processing machine including a control part for adjusting the amplitude of a piezoelectric element or adjusting a repulsive force between the magnets.

According to an aspect of the present invention, there is provided a light guide plate having a rectangular plate shape, having protruding dots for light scattering on its surface, light incident on a side surface thereof, and height of protruding dots for light scattering formed on the light- Thereby providing a side light guide plate lower than the height of the protruding dots for light scattering formed.

The light guide plate is manufactured by injecting a transparent resin into a light guide plate mold and filling and cooling the light guide plate. Accordingly, the dots formed on the light guide plate and the light guide plate are made of the same material, and the light guide plate and the dots are physically integrated.

In the light guide panel mold according to the present invention, dimples having a deep depth are formed in the large light portion and dimples having a shallow depth are formed in the light incident portion, so that the density of the dots is low. As a result, machining time due to toot processing is reduced, and cost reduction is possible. In the light guide plate mold according to the present invention, when improvement of luminance is required after the production of the primary sample metal mold, dimples deeper than the primary sample metal mold are formed at portions where brightness improvement is required, so that the density of the dimples can be prevented from increasing have.

The light guide plate mold having different dimple depths according to the present invention can adjust the amplitude of the piezoelectric element by controlling the voltage applied to the piezoelectric element by the control unit in real time according to the depth data of the dimples for each area stored in advance, And adjusting the elasticity of the elastic member supporting the bite.

In addition, since the light guide plate manufactured according to the present invention has dots of different heights on the surface of each region, uniform and high brightness can be manifested and the problem of defect due to an increase in the dot density can be solved.

1 (a) is a side view, and FIG. 1 (b) is a cross-sectional view taken along a line NN in FIG. 1 (a) as part of a patterning head using a piezoelectric element according to the prior art.
Fig. 2 is a diagram showing the operation of a pattern forming head using a piezoelectric element according to the prior art. Fig. 2 (a) shows a state where the byte is at the maximum height (top dead center) .
FIG. 3 is a view showing the entirety of a pattern processing machine for a depth variable light guide plate mold according to the present invention.
FIG. 4 is a side view of a patterning head of a light guide plate mold having a pair of magnets according to one embodiment of the present invention, and FIG. 4 (b) is a cross-sectional view taken along the line NN in FIG.
Fig. 5 is a side view of a patterning head of a light guide plate mold having a pair of magnets according to one embodiment of the present invention. Fig. 5 (a) is a side view and Fig. 5 (b) is a sectional view taken along the line NN in Fig.
6 shows an elastic control device using a DC motor according to an embodiment of the present invention.
7 is an enlarged view of an elastic control device using a ball screw motor according to another embodiment of the present invention.
8 is an enlarged view of an elastic control device using a linear motor according to another embodiment of the present invention.
FIG. 9 is a graph showing the amount of change in depth according to the descent height of the magnet in the patterning head according to the present invention.
10 is a photograph of a surface of a light guide plate mold having different depths for each region by using patterning heads according to the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings. The following examples illustrate the invention and are not intended to limit the invention. Additional aspects, features, and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. In order to facilitate a clear understanding of the present invention, some of the elements in the figures may be exaggerated, omitted or schematically illustrated. Also, the size of each component does not entirely reflect the actual size.

3 is a schematic view of a mold processing machine capable of forming a light guide plate mold having different depths in different regions. The mold processing machine 200 includes a pattern forming head 210 for forming a dimple by hitting the surface of the mold with a bite, a data storage unit 220 for storing data on the depth of the dimple to be processed for each mold area, A control unit 230 for controlling the voltage applied to the piezoelectric elements in accordance with the position of the pattern formation head and controlling the elasticity of the pattern formation head so as to form dimples having different depths according to data stored in the formation head 10, And an elastic control device 240 for controlling the elasticity of the pattern forming head by the controller 230.

FIG. 4 shows a depth variable pattern forming head 210 according to an embodiment of the present invention, and FIG. 5 shows a portion of the pattern forming head 210 excluding the piezoelectric element fixing member 12. In each drawing, (A) is a side view and (B) is a cross-sectional view taken along the line NN in the side view. The detailed configuration of the pattern forming head 210 will be described in detail with reference to FIGS. 1 and 2. FIG.

4, the pattern forming head 210 includes a piezoelectric element 11. The piezoelectric element 11 is fixedly supported by the piezoelectric element fixing block 12 such that the longitudinal direction thereof is perpendicular to the longitudinal direction. do. The piezoelectric element fixing block 12 has a mounting portion 121 for mounting to the header fixing portion 3 of the pattern machine of FIG. 5 and a holder supporting portion 122 for slidably supporting the elastic member holder 13, .

As understood by a person skilled in the art, a piezoelectric element means a device having a piezoelectric phenomenon in which a voltage is generated when a mechanical pressure is applied and a mechanical deformation occurs when a voltage is applied. In other words, it refers to a device that has the property that electric polarization occurs when an external force is applied and a potential difference occurs, and when the voltage is applied, deformation occurs. In the present invention, the piezoelectric element 11 is operated by using the latter property. When a voltage of a predetermined frequency is applied to the piezoelectric element 11, the lower end (terminal) of the piezoelectric element 11 is shifted by a period corresponding to the frequency , And the reciprocating motion in which the length is increased and decreased repeatedly, that is, the vibration is caused.

An elastic member holder 13 is coupled to the piezoelectric element fixing block 12 under the piezoelectric element 11 so as to be slidable up and down while maintaining a vertical direction. To this end, the piezoelectric element fixing block 12 includes a holder supporting portion 122, and the elastic member holder 13 includes a sliding coupling portion 134 which is positioned between the piezoelectric element 11 and the holder supporting portion 122 And the LM guide 20 is positioned between the holder support portion 122 and the sliding engagement portion 134. [ The elastic member holder 13 receives up-and-down vibration of the piezoelectric element 11 and vibrates up and down at the same amplitude and period as the vibration of the lower end of the piezoelectric element 11. [ That is, when the lower end of the piezoelectric element 11 is elongated, the elastic member holder 13 is lowered by the extended length, and when the lower end of the piezoelectric element 11 is contracted, the elastic member holder 13 is lifted do. The spring 21 is fastened between the upper end of the sliding engagement portion 134 and the piezoelectric element fixing block 12 to raise the elastic member holder 13. When the piezoelectric element 11 is contracted, The member holder 13 is pulled.

As shown in Figs. 4 and 5, elastic members made of permanent magnets in the form of a pair of discs in which a repulsive force acts are located inside the elastic member holder 13. A through hole 131 is formed in the lower portion of the elastic member holder 13 and the byte holder 15 is mounted through the elastic member holder 13.

The bite holder 15 is mounted in the elastic member holder 13 and a part of the bite holder 15 is located outside the elastic member holder 13 with respect to the elastic member holder 13, A relatively wide and flat head 151 and a leg 152 that is relatively narrow and elongated, preferably a polygonal, more preferably cylindrical. The outer diameter of the head portion 151 is formed to be larger than the inner diameter of the through hole 131 of the elastic member holder 13 so that the byte holder 15 is prevented from escaping downward from the elastic member holder 13. The vertical section of the byte holder 15 has a "T" shape, for example.

The head portion 151 is in contact with the lower inner surface of the elastic member holder 13 and the distal end of the leg portion 152 is located below the through hole 131 of the elastic member holder 13. [ The leg portion 152 is fitted with a bite 16 directly bumping against the mold core to directly form a plurality of dimples. The longitudinal center axes of the piezoelectric element 11 and the bite 16 are formed coaxially with each other and coincide with the central axis of the pattern forming head.

The through hole 131 of the elastic member holder 13 surrounds at least part of the leg portion 152 of the byte holder 15 so that the center axis of the byte holder 15 does not deviate from the central axis of the pattern forming head And the inner diameter of the through hole 131 is substantially the same as the outer diameter of the holder leg portion 152. [ Here, "substantially the same" means that a difference in diameter is large enough to allow the bite holder 15 to be displaced upward through the through hole 131 when an external force is applied below the bite holder leg portion 152, But it should be understood to include the meaning that it can exist.

The elastic member holder 13 is provided with a first permanent magnet 14 which is in contact with the upper surface of the head 151 of the bite holder 15 and a second permanent magnet 14 which applies a repulsive force to the first permanent magnet 14 And a second permanent magnet 19 is present. The elastic member holder 13 includes a control plate 133 whose height is adjusted by the controller 240 and in which a perforation hole is formed at the center of the control plate 240, The second permanent magnet 19 is inserted into the annular groove formed in the lower portion of the throttle plate 133 by drilling the center portion of the second permanent magnet 19, do. When the throttle plate 133 is lowered by the control unit 240 driven in accordance with the information of the controller 230, the distance between the first permanent magnet 14 and the second permanent magnet 19 becomes closer to each other, The magnet 14 presses the bite holder 15 more firmly, so that when the bite strikes the metal mold, the resilient supporting force becomes strong and the depth of the hole becomes deep. Conversely, when the throttle plate 133 is elevated, the distance between the first permanent magnet 14 and the second permanent magnet 19 is increased and the repulsive force is reduced, so that the bite holder 15 is pressed down more weakly, The elastic supporting force is weak when the hitting is performed, so that the depth of the hole becomes shallow.

The process of puncturing using the pattern forming head 10 according to the present invention is disclosed in Korean Patent No. 10-1299974 to the present applicant, which is hereby incorporated by reference in its entirety.

In Fig. 6, an elastic control device 240 using a DC motor 242 is shown in order to adjust the elasticity by adjusting the position of the second permanent magnet 19 of the present invention. When the motor shaft 243 is rotated in the left direction by controlling the amount of current applied to the DC motor 242 in the control unit (not shown), the push rod 241 interlocked with the rotation shaft rotates to rotate the second permanent magnet 19, The position of the second permanent magnet 19 rises while the push rod 241 interlocked with the rotary shaft rotates in the opposite direction.

In FIG. 7, an elasticity control device 240 using a ball screw motor 252 is shown to adjust the elasticity by adjusting the position of the second permanent magnet 19 of the present invention. When the ball screw motor 252 is operated in a control unit (not shown), the pressure plate 253 attached to the ball screw motor 252 lowers the position of the second permanent magnet 19, The pressure plate 253 attached to the first permanent magnet 252 raises the position of the second permanent magnet 19.

8 shows an elastic control device 240 using a linear motor 262 in order to adjust the elasticity by adjusting the position of the second permanent magnet 19 of the present invention. When the linear motor 262 is operated in a control unit (not shown), the pressing plate 263 attached to the linear motor 262 lowers the position of the second permanent magnet 19, So that the position of the second permanent magnet 19 is raised.

As shown in FIG. 9, when the height of the second permanent magnet of the present invention is adjusted, the depth may be nonlinear, for example, a quadratic function depending on the degree of descent.

As shown in FIG. 10, the depth and density of the dots of the mold according to the present invention are different from each other, so that the light guide plate having different densities and heights can be formed.

10: Pattern forming header
11: piezoelectric element
12: Piezoelectric element fixing member
13: Elastic member holder

Claims (17)

A piezoelectric element which vibrates up and down according to an applied voltage;
An elastic member holder vibrating up and down according to the vibration of the piezoelectric element and having a hole formed at a lower end thereof;
The upper end being located inside the elastic member holder and the lower end being inserted into the hole formed at the lower end of the elastic member holder and projecting out of the elastic member holder through the hole;
A bite mounted on the bite holder to form a plurality of dimples on a mold surface; And
And an elastic member made of a pair of magnets in which a repulsive force acts on the inside of the elastic member holder, wherein the pair of magnets includes a first magnet for supporting an upper surface of the bite holder, And a second magnet having a repulsive force with respect to the first magnet,
A data storage unit for a depth of the dimple to be processed for each region of the mold,
A controller for controlling a repulsive force between the magnets by adjusting a height of an upper magnet in real time according to the stored data; And
A second magnet height adjusting device
/ RTI >
Forming a dimple having a depth of 1 to 3 micrometers in a low luminance region, forming a dimple having a depth of 3 to 10 micrometers in a high luminance region,
Wherein the dimple in the low luminance region and the dimple in the high luminance region are struck so as to have a depth difference of 0.5 micrometers or more. The apparatus of claim 1, wherein the control unit controls the voltage applied to the piezoelectric element to adjust the depth of the dimple according to the data. delete [2] The patterning tool of a light guide plate mold pattern according to claim 1, wherein the height adjusting device of the second magnet comprises an extension piece which is fixed or contacted with the second magnet and extends to the outside of the elastic member holder. 5. The patterning machine for a light guide plate mold pattern according to claim 4, wherein the extension is adjusted in height by a motor controlled by a control unit. The light guide plate mold pattern processing machine according to claim 5, wherein the motor is a DC motor, a ball screw motor, or a linear motor.

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