KR100859293B1 - Light guide film for keypad backlight using prism pattern shape to improve irradiation efficiency and manufacturing method - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light guide film for a keypad backlight for improving irradiation efficiency and a method of manufacturing the same. The present invention relates to a pattern of a keypad backlight light emitting device which is provided on the back of a numeric keypad such as a mobile phone and supplied to the front of the keypad.

Back light guide film for illuminating the keypad is installed on the back of the keypad according to an embodiment of the present invention is made of a polycarbonate material, about 0.05 ~ 0.125 mm to illuminate the light emitted from the light source in the direction of the keypad A prism pattern is formed on the upper surface of the thin film, and a prism pattern is formed in a corresponding area where the keypad is arranged on the upper surface of the thin film, so that the light emitted from the side light source is scattered and collected in the prism pattern. Or a pyramid pattern, and a lower surface prism pattern formed in any one of a straight line, a radiation, or an arc shape on the entire lower surface of the thin film.

Keypad Illuminator, Backlight, Light Guide Film, Prism Pattern, Pyramid Pattern

Description

LIGHTGUIDE FILM FOR BACKLIGHT FOR INCREASING IRRADIATION EFFECTS AND METHOD THEREOF} Keypad Backlight Using Prism Pattern to Improve Irradiation Efficiency

1A illustrates a light guide film for a keypad backlight to which a prism pattern is applied according to a first embodiment of the present invention;

FIG. 1B is an enlarged cross-sectional view of a portion AA ′ of FIG. 1A;

2A is a flowchart illustrating a manufacturing process of a light guide film for keypad backlight to which a prism pattern is applied according to a first embodiment of the present invention;
2B is a view illustrating an exemplary type of formation of a prism pattern formed on the entire lower part of the light guide film.

3A illustrates a light guide film for a keypad backlight to which a prism pattern is applied according to a second embodiment of the present invention;

3B is an enlarged view of a section of the portion BB ′ of FIG. 3A;

4A illustrates a light guide film for a keypad backlight to which a prism pattern is applied according to a third embodiment of the present invention;

4B is an enlarged view of a cross section of part C-C ′ of FIG. 4A;

5 is an exploded perspective view of a mobile phone for explaining the function of a conventional light guide plate for keypad backlight;

6A illustrates a conventional keypad backlight light guide plate;

FIG. 6B is an enlarged cross-sectional view of a portion 'D-D' of FIG. 6A;

6C is a flowchart illustrating a manufacturing process of the keypad backlight LGP of FIG. 6A;

<Explanation of symbols for the main parts of the drawings>

200, 300, 400: Light guide film 210, 310, 410: LED light source

230, 330, 430: Prism, pyramid or dot pattern formed at keypad placement position

240, 440: Prism pattern formed on the entire lower surface of the light guide film

The present invention relates to a light guide film for a keypad backlight for improving irradiation efficiency and a method of manufacturing the same. More particularly, the present invention relates to a pattern of a keypad backlight light emitting device that is installed at the back of a numeric keypad such as a mobile phone and supplies it to the front of the keypad. The present invention relates to a light guide film for a keypad backlight and a method of manufacturing the same for forming a prism pattern in a pattern shape of a light guide device for guiding light emitted from a light source to improve irradiation efficiency of light irradiated to the entire keypad.

5 is a diagram illustrating a conventional use example of the light guide film for the keypad backlight. As shown in FIG. 5, in general, the keypad 20 is a keypad for making a call or inputting a text from a number or a mobile terminal such as a mobile phone, and the like. For example, in order to identify in a dark place, a lighting device is needed to illuminate the keypad from the back of the keypad. The keypad backlight may be used as the light guide plate 100 as described later in FIGS. 6A to 6C. On the other hand, a light guide plate for a backlight used in the back of an LCD panel used in a mobile phone or the like has been developed by focusing on uniform light irradiation and thickness of the light guide plate in the liquid crystal panel portion. However, in the case of the above-described light guide plate 100 for keypad backlight, the development is focused on the reduction of the thickness of the light guide plate and how high the brightness can be irradiated to the keypad. Thus, the light guide plate for the backlight for the keypad serves as a lighting device for illuminating the keypad.

FIG. 6A is a view illustrating a conventional keypad backlight LGP, and FIG. 6B is an enlarged cross-sectional view of a portion 'D-D' of FIG. 6A, and FIG. 6C is a diagram illustrating a manufacturing process of the keypad backlight LGP of FIG. 6A. It is a flow chart.

A conventional keypad backlight light guide plate and a manufacturing method thereof shown in FIGS. 6A to 6B are described in detail in Korean Patent Registration No. 10-610330.

6A and 6B, the light guide plate 100 is a flexible polycarbonate (PC) material, and the light emitted from the light source 110 is reflected on the rear surface of the light guide plate 100 to be uniformly supplied to the keypad in the form of a surface light source by diffusion or scattering. The predetermined dot pattern 111 is formed so that the density increases as it moves away from the light source.

The dot pattern 111 is a hot stamping, fabricated pattern to form a pattern of irregularities by transferring the pattern formed in the stamper mold to the light guide plate by pressing the light guide plate by applying a predetermined pressure after heating the stamper mold on which an arbitrary pattern is formed. Injection molding to form a pattern of irregularities on the light guide plate by using a mold, and processing of micro blast, laser, etc. to form a pattern of irregularities by spraying fine materials such as sand grains and glass grains on the light guide plate with a spray It can be formed by the method.

As shown in FIG. 6C, the conventional keypad backlight LGP 110 etches, or corrodes, a predetermined pattern on one side of a hot stamper mold (S10), and then, the mold having the pattern etched thereon is 150 ° C. to 250 ° C. FIG. Heated to a degree (S20), by applying a constant pressure by a method such as air pressure or hydraulic pressure is produced by transferring the pattern to the light guide plate by pressing the light guide plate of the polycarbonate material and the primary processing is completed by a CNC machine or press punching mold (S30). .

Although the light guide plate manufactured in the above-described conventional dot pattern shape has achieved a certain purpose in terms of thickness of the light guide plate, although it guides the light emitted from the light source to the keypad portion where the information is displayed, there is a lot of light loss. The disadvantage is that the luminance of light emitted to the front is not higher than the amount of incident light. Accordingly, there is a problem that the irradiation efficiency of light of the light guide plate (or light guide film) for keypad backlight for illuminating the keypad of the mobile phone remains.

SUMMARY OF THE INVENTION An object of the present invention made in view of the above is to apply a prism pattern to a light guide film for a keypad backlight, thereby improving light irradiation efficiency and improving irradiation efficiency, thereby reducing the number of LEDs required or the same number of LEDs. In the case of using, the luminance can be improved.

Back light guide film for illuminating the keypad is installed on the back of the keypad according to an embodiment of the present invention is made of a polycarbonate material, about 0.05 ~ 0.125 mm to illuminate the light emitted from the light source in the direction of the keypad It is a transparent thin film, and a prism pattern formed in a shape slightly larger than the keypad is formed at a corresponding position where the keypad is arranged on the upper surface of the thin film, so that the upper surface keypad for scattering and condensing light emitted from the light source of the side surface in the prism pattern A prism or pyramid pattern, and a lower surface prism pattern formed in any one of a straight line, a radiation, or an arc shape on the entire lower surface of the thin film.

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In the light guide film for backlight according to the embodiment of the present invention, it is preferable to form the prism pattern by a V grooving method using a precision processing machine.

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Back light guide film for illuminating the keypad is installed on the back of the keypad according to another embodiment of the present invention is made of a polycarbonate material of about 0.05-0.125 mm to illuminate the light emitted from the side light source in the direction of the keypad It is a transparent thin film, and a dot pattern is formed on the upper surface of the thin film with a slightly larger area than the keypad at a corresponding position where the keypad is arranged, so that the upper surface keypad scatters and condenses the light emitted from the light source on the side surface in this dot pattern. The dot pattern and the lower surface prism pattern formed in the shape of any one of a straight line, a radiation, or an arc shape in the whole lower surface of the said thin film are characterized by the above-mentioned.

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According to another embodiment of the present invention, a method of manufacturing a light guide film for backlight having a prism pattern formed on the entire bottom surface of the keypad to illuminate the keypad may include a height, a pitch, an angle, and the like of the prism pattern to be formed on the light guide plate. Designing and simultaneously designing a mold core; Preparing a mold core and plating an electroless nickel plated layer on the mold core by about 50-200 μm; V-grooving the V-groove according to an already designed prism pattern by attaching a diamond bite to an ultra-precision machine with the mold core plated with the electroless nickel plating layer; Processing the mold core having the prism pattern formed thereon and mounting the mold core to a press machine; Manufacturing a light guide film by transferring a prism pattern to a flexible material such as polycarbonate in the press; And cutting the light guide film formed by transferring the prism pattern to a predetermined size after the inspection, to complete the light guide film.

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The light guide film manufacturing method according to another embodiment of the present invention is characterized in that the prism pattern formed on the entire lower surface is formed in any one of a straight line, a radiation, and an arc.

(Example 1)

Hereinafter, a light guide film for keypad backlight and a method of manufacturing the same, which apply a prism pattern shape for improving irradiation efficiency according to an embodiment of the present invention, will be described with reference to FIGS. 1 to 4.

First, the keypad backlight light guide film to which the prism pattern shape is applied to improve light irradiation efficiency will be described, and then a manufacturing method thereof will be described.

FIG. 1A is a view illustrating a light guide film for a keypad backlight to which a prism pattern is applied according to a first embodiment of the present invention, and FIG. 1B is an enlarged cross-sectional view of part AA ′ of FIG. 1A.

In FIG. 1A, the light guide film 200 is about 0.05-0.125 mm Made of thin, flexible polycarbonate (PC) material, each cell phone or handheld device such as a PDA can be placed on the bottom of a number, symbol or function keypad to recognize numbers or letters on the keypad. It functions as a surface light source that illuminates.

The light guide film 200 has a plurality of chip LEDs 210 formed as light sources on one side thereof, and the light emitted from the chip LEDs 210 is reflected through the surface of the light guide film 200 to scatter or condense. It is uniformly supplied to the keypad in the form of surface light source. The light guide film 200 as the surface light source is disposed on the back of the keypad, light is scattered or condensed on the V groove portion 230, which is a prism pattern formed on the bottom of the keypad of the light guide film, so that the letters engraved on the keypad can be illuminated, even in a dark place. The number or letters on the keypad can be recognized.

Therefore, as already described in the prior art portion of the detailed description of the present invention, the light guide film 200 for the keypad backlight needs to improve the light irradiation efficiency, and according to the following embodiment, The purpose of improving can be achieved. Hereinafter, a light guide film for a keypad backlight having improved light irradiation efficiency will be described in detail.

As illustrated in FIGS. 1A and 1B, the light guide film 200 according to the first exemplary embodiment of the present invention includes a prism pattern 230 on an upper surface formed at each position where a numeric keypad is disposed, and a prism formed on the entire lower surface. The pattern 240 is formed. When the prism pattern is formed on the upper and lower portions of the light guiding film 200, when the same light source is used as compared to the light guiding film 100 having the dot shapes shown in FIGS. 6A and 6B, 30% or more of irradiation is performed. The efficiency is improved.

By improving such irradiation efficiency, the required number of LEDs as the light source 210 formed in the side surface becomes small. In other words, fewer LEDs are required to display the same brightness compared to the prior art, and if the same LED number is used, brightness of 30% or more is improved compared to the prior art.

Hereinafter, a method of forming a prism pattern formed on the light guide film 200 will be described with reference to FIGS. 2A and 2B.

2A is a flowchart illustrating a manufacturing process of a light guide film for a keypad backlight to which a prism pattern is applied according to a first embodiment of the present invention, and FIG. 2B is a view illustrating an exemplary type of forming a prism pattern formed on an entire lower part of the light guide film. One drawing.

On the light guide film 200 according to the first embodiment of the present invention, the prism patterns 230 and 240 are formed by V-grooving by an ultra precision processing machine.

As shown in Figure 2a, the light guide film manufacturing process by the v grooving process is as follows.

The height, pitch, angle, etc. of the prism pattern to be formed on the light guide film are designed, and at the same time, a mold core is designed (S210).

A mold core is prepared, and an electroless nickel plating layer is plated on the mold core about 50-200 μm (S220).

A mold core coated with an electroless nickel plated layer is mounted with a diamond bite on a fine precision machine, and then V-grooving the V groove according to the prism pattern designed in step S210. In this case, the V-groove formed according to the V-groove grooving of the prism pattern may form the V-groove in a straight line, an arc, a radial form, and a wave form as shown in FIG. 2B as well as in the form of a transverse or longitudinal straight prism. It may be (S230). Forming various types of prism patterns in FIG. 2B has the side effect of eliminating various design constraints in designing the mobile phone, thereby facilitating the design of the mobile phone.

On the other hand, in the first embodiment of the present invention, according to the V grooving for forming the V groove, the prism pattern forms a prism pattern in the longitudinal direction, and also forms a prism pattern in the transverse direction, thereby forming a triangular pyramid or pyramidal shape pattern. It can be seen that can be easily formed.

The prism pattern or pyramid pattern formed by such V groove grooving can maintain a uniformity of quality compared to etching or laser processing of a conventional dot pattern, and is excellent in workability. That is, chemical processing such as etching has a disadvantage in that it is difficult to control the depth of a dot pattern, etc., and laser processing has high luminance due to scattering of light in the bur part due to generation of bur in the processing part. There is a difficulty that cannot be obtained. However, V grooving by precision machining with the diamond bite used in the present invention is a mechanical processing suitable for processing a prism pattern, which has the advantage of maintaining uniform quality and excellent workability.

After processing the mold core in which the prism pattern is formed, it is mounted on the press machine (S 240).

A light guide plate sheet is manufactured by transferring a prism pattern to a flexible material such as polycarbonate in a press (not shown) (S 250).

Then, the light guide film formed by transferring the prism pattern is cut to a predetermined size after inspection to complete the light guide film 200 (S260).

In the light guide film manufactured according to the first embodiment of the present invention, the light from the light source is reflected and refracted by the prism pattern 240 formed on the lower surface to be directed to the upper surface, and the prism pattern 230 formed on the upper surface. By condensing by the excellent light emitting efficiency of the light guide film 200, it is possible to improve the irradiation efficiency of at least 30% or more than the light guide film 100 of the dot pattern described in the prior art.

Example 2

 Hereinafter, a second embodiment of the present invention will be briefly described with reference to FIGS. 3A and 3B.

FIG. 3A illustrates a light guide film for a keypad backlight to which a prism pattern is applied according to a second embodiment of the present invention, and FIG. 3B is an enlarged cross-sectional view of a portion B-B 'of FIG. 3A.

The light guide film 300 for the keypad backlight to which the prism pattern is applied according to the second embodiment of the present invention is formed by forming the prism pattern 330 only at each portion where the keypad is disposed on the lower surface of the light guide film. It can be prepared in the same manner. It is clear that the light guide film 300 manufactured according to the second embodiment of the present invention has a relatively low irradiation efficiency of light from the light source compared to the light guide film 200 manufactured according to the first embodiment. Nevertheless, the light irradiation efficiency of the light guide film 300 manufactured according to the second embodiment of the present invention is about 10% of the light guide film 100 manufactured by the conventional dot pattern when the same light source is used. There is an effect of improving the brightness.

(Example 3)

Hereinafter, a third embodiment of the present invention will be briefly described with reference to FIGS. 4A and 4B.

FIG. 4A illustrates a light guide film for a keypad backlight to which a prism pattern is applied according to a third embodiment of the present invention, and FIG. 4B is an enlarged cross-sectional view of a portion C-C 'of FIG. 4A.

In the light guide film 400 for the keypad backlight to which the prism pattern according to the third embodiment of the present invention is applied, a dot pattern 430 is formed on each portion of the keypad on the top surface of the light guide film, as in the conventional art. The prism pattern 440 is formed on the entire lower surface. It can be produced in the same manner as in the first embodiment.

Irradiation efficiency of light of the light guide film 400 manufactured according to the third embodiment of the present invention compared to the light guide film 100 manufactured according to the prior art light irradiation efficiency of the light guide manufactured by a conventional dot pattern It was found by the measurement results that there was an effect of improving brightness by about 30% over the film 100.

In the light guide film for keypad backlight of the prism pattern manufactured according to the embodiment of the present invention, the irradiation efficiency of light of the light source is improved, and the irradiation efficiency is improved, thereby reducing the number of required LEDs or using the same number of LEDs. There is an advantage that can improve the brightness.

According to an embodiment of the present invention, by forming the prism pattern on the light guide film for keypad backline by V grooving method, there is an advantage that can reduce the defective rate and reduce the manufacturing cost in the product manufacturing process.

Claims (6)

delete delete delete delete In the method for manufacturing a light guide film for the backlight is provided on the back of the keypad to form a prism pattern on the entire lower surface for illuminating the keypad, Designing the height, pitch, angle, etc. of the prism pattern to be formed on the light guide film, and simultaneously designing a mold core, Manufacturing a mold core, and plating about 50-200 um of an electroless nickel plating layer on the mold core, V-grooving the V-groove according to an already designed prism pattern by attaching a diamond bite to a microprecision machine with the mold core plated with the electroless nickel plating layer, Processing the mold core having the prism pattern formed thereon and mounting it to a precision press; Manufacturing a light guide film by transferring a prism pattern to a flexible material such as polycarbonate in the press; And cutting the light guide film formed by transferring the prism pattern to a predetermined size and then completing the light guide film. The method of claim 5, The prism pattern formed in the whole lower surface is formed in any one shape of a straight line, a radiation, and an arc.

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