JP2009154426A - Method for producing light transmission plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a light transmission plate by which in formation of a reflection pattern by ultrasonic machining, the occurrence of unevenness in the surface is prevented by adjusting the unevenness of a reflection pattern. <P>SOLUTION: The method for producing a light transmission plate 3 by which light made incident from the edge face is exited from the main face, includes: a forming step where the main face of the light transmission plate 3 is contacted with an ultrasonic machining horn 101, and a recessed part group composed of a plurality of recessed parts 13 deflecting the progressing direction of the light made incident from the edge face is formed; and an adjusting step where the recessed part group formed at the main face of the light transmission plate 3 by the forming step is contacted with the ultrasonic machining horn 101, and the dimensions of the plurality of the recessed parts 13 composing the recessed part group are adjusted to almost uniform dimensions. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a light guide plate, a light guide plate, and a light-emitting signboard using the light guide plate.

  Conventionally, a light guide plate that emits light incident from an end face from both main surfaces of the light guide plate is known. As such a light guide plate, there is a light guide plate used in the illumination device described in Patent Document 1.

JP 2007-299716 A

  Specifically, the lighting device described in Patent Document 1 includes a light guide plate, and a first display panel and a second display panel arranged so as to sandwich the light guide plate. And such an illuminating device emits the light which injected into the light guide plate from light sources, such as LED arrange | positioned at the end surface of a light guide plate, from both main surfaces of a light guide plate, and the 2nd display panel and 2nd. The display panel is illuminated from the back.

  However, when such an illuminating device is applied to a relatively large device such as a liquid crystal monitor or a light-emitting signboard, it performs its function due to the insufficient amount of light emitted from the light guide plate. There was a problem that was difficult. Therefore, as a method of increasing the amount of light emitted from such a light guide plate, there is a method of forming a reflection pattern on the light guide plate by ultrasonic processing as in the invention described in Patent Document 2. When such a reflection pattern is formed, the reflection pattern is formed by mounting the ultrasonic processing horn on a predetermined ultrasonic processing machine and bringing the ultrasonic processing horn into contact with the light guide plate work a plurality of times.

JP 2007-66699 A

  However, when such a reflection pattern is formed by ultrasonic processing, the reflection pattern is formed by bringing an ultrasonic processing horn 101 as shown in FIG. 10 into contact with the light guide plate work. For example, when the output of the ultrasonic processing horn 101 is taken into consideration, the reflection pattern is formed over the entire surface of the light guide plate work due to the fact that the size of the processed portion of the horn cannot be more than a certain size. When doing so, the ultrasonic processing horn 101 is repeatedly brought into contact with the light guide plate workpiece. At this time, the ultrasonic processing horn 101 once contacts the processing surface of the light guide plate workpiece, and then moves in the direction of arrow A from the upper left of the processing surface of the light guide plate workpiece 103, for example, as shown in FIG. It contacts the processed surface of the light guide plate work 103 again. At this time, the ultrasonic processing horn 101 moves so that each reflection pattern does not overlap with an adjacent reflection pattern, and performs processing. When the ultrasonic processing horn 101 reaches the right end of the light guide plate workpiece 103, the ultrasonic processing horn 101 moves downward in the light guide plate 3 and moves from the left side to the right side of the light guide plate 3 (in the direction of arrow B). ) Apply processing while moving. The light guide plate formed by such a series of processing is in a state in which a reflection pattern is formed over the entire surface, as shown in FIG.

  Then, when light is incident from one end face of the light guide plate subjected to such a series of processing, the light guide plate emits light as shown in FIG. The light guide plate of the photograph shown in the figure has a diffusion plate disposed on the main surface thereof. As is clear from the figure, streaks are generated in the vertical and horizontal directions on the surface of the light guide plate. This is a processing mark generated during processing by the ultrasonic processing horn 101. That is, since the ultrasonic processing horn 101 is relatively large compared to the size of each reflection pattern, the reflection pattern formed on the surface of the light guide plate even when the ultrasonic processing horn 101 is slightly inclined. Unevenness occurs in the size. When light is incident on the light guide plate on which the reflection patterns having different sizes are formed, unevenness occurs on the surface due to the unevenness of the reflection patterns.

  Therefore, the present invention has been made in view of such circumstances, and when a reflection pattern is formed by ultrasonic processing, unevenness of the reflection pattern is adjusted to prevent unevenness on the surface. An object of the present invention is to provide a method for manufacturing a light guide plate.

  In order to solve the above problems, a light guide plate manufacturing method according to the present invention is a light guide plate manufacturing method in which light incident from an end surface is emitted from a main surface. A first forming step of forming a first recess group comprising a plurality of recesses for contacting a horn and deflecting a traveling direction of light incident from the end face; and the ultrasonic processing horn on a main surface of the light guide plate And a second formation step of forming a second recess group consisting of a plurality of recesses for deflecting the traveling direction of the light incident from the end face, and the second recess group includes the first recess group. It is characterized by being formed so as not to overlap with the recess group.

  According to this configuration, even when the size of the plurality of recesses constituting the first recess group formed in the first forming step is not uniform, the first recess group is not overlapped with the first recess group. By forming the two recess groups, the unevenness of the recesses formed over the entire main surface of the light guide plate can be corrected.

  As described above, according to the present invention, it is possible to prevent unevenness on the surface by adjusting the non-uniformity of the recesses.

  As shown in FIG. 1, the light-emitting signboard 1 according to the embodiment includes a light guide plate 3, a diffusion plate 5, a display plate 7, and a reflection plate 9. Such a light-emitting signboard 1 emits light incident from the side surface of the light guide plate 3 from one main surface of the light guide plate 3. The light emitted from the main surface of the light guide plate 3 is diffused by the diffusion plate 5 and irradiated from the back surface of the display plate 7. Further, the light traveling in the direction of the other main surface of the light guide plate 3 is reflected in the direction of the one main surface of the light guide plate 3 by the reflecting plate 9 disposed close to the other main surface of the light guide plate 3.

  As shown in FIG. 2, the light guide plate 3 is formed by processing a plurality of recesses 13 on the surface of a light guide plate work 11 made of, for example, an acrylic plate having a predetermined size. Such a recess 13 deflects the traveling direction of light incident on the light guide plate 3 from the end face of the light guide plate 3. And the recessed part 13 is formed by ultrasonic processing.

  As described above, the ultrasonic processing apparatus for forming the concave portion 13 includes the ultrasonic processing horn 101 as shown in FIG. A processing dot 105 having a shape corresponding to the concave portion 13 is formed at the tip of the ultrasonic processing horn 101. Each processing dot 105 has a quadrangular pyramid shape with a height of about 0.3 mm, for example. The length of the diagonal line on the bottom surface of each processing dot 105 is about 1.8 mm. At the tip of the ultrasonic processing horn 101, an even number of such processing dots 105 are arranged in the vertical and horizontal directions. Specifically, the plurality of processing dots 105 are arranged at equal intervals in the vertical direction and the horizontal direction, respectively. Of the plurality of processing dots 105, four processing dots 105 adjacent in the vertical direction and the horizontal direction are arranged so as to form a square. Then, when the ultrasonic processing horn 101 is moved by a predetermined carrier and each processing dot 105 is brought into contact with the surface of the light guide plate workpiece 11, 144 pieces of 12 × 12, for example, are formed on the surface of the light guide plate workpiece 11. A recess 13 is formed. When manufacturing the light guide plate 3, the tip of the ultrasonic processing horn 101 is brought into contact with the light guide plate workpiece 11 to form the 144 concave portions 13, and then the ultrasonic processing horn 101 is removed from the light guide plate workpiece 11. After separation, the ultrasonic processing horn 101 is brought into contact with the light guide plate work 11 again. By repeatedly executing these operations, the concave portion 13 is formed uniformly on the surface of the light guide plate 3.

  By the way, such an ultrasonic processing horn 101 is fixed to a carrier by an operator's manual work, for example, but in the case of manual fixing, it is difficult to fix the ultrasonic processing horn 101 accurately. . As described above, since the size of each recess 13 is very small, even when the ultrasonic processing horn 101 is slightly displaced and fixed, each recess 13 is formed unevenly. For example, when the axis of the ultrasonic processing horn 101 is inclined as shown in FIG. 3, the recess 13 formed thereby has a non-uniform shape as shown in FIG. Specifically, among the plurality of recesses 13, the recesses 13 in the direction in which the ultrasonic processing horn 101 is inclined increase, and the size of the recesses 13 decreases as the distance from the recess 13 increases. And the depth of the some recessed part 13 formed in this way becomes non-uniform | heterogenous, and the nonuniformity will arise also in the light inject | emitted from a light-guide plate as shown in FIG. In particular, in the case of mass production of the light guide plate, since the inclination of the ultrasonic processing horn 101 slightly shifts every time the ultrasonic processing horn 101 comes into contact with the light guide plate work 11, such a phenomenon is remarkable. Occurs.

  Accordingly, an object of the present invention is to adjust the non-uniformity of the concave portion 13 formed in the light guide plate 3 even when the ultrasonic processing horn 101 is slightly inclined to prevent the occurrence of light unevenness. It is to be.

  In order to prevent the occurrence of such unevenness, in the method of manufacturing the light guide plate according to the present invention, the concave portion 13 is once formed by the ultrasonic processing horn 101, and then the ultrasonic processing horn 101 is used again. To adjust the variation of the recess 13. That is, when the concave portion 13 is formed by using the ultrasonic processing horn 101, the 144 concave portions formed by the ultrasonic processing horn 101 at one time, for example, as shown in FIG. The concave portion 13 at the bottom is the largest, and the concave portion 13 at the lower right is the smallest. When these recess groups are formed so as to be adjacent to each other, the relatively large recesses 13 are concentrated in a partial area of the light guide plate work 11, while the relatively small recesses are formed in a partial area of the light guide plate work 11. 13 will be concentrated. In other words, in the present invention, after the light guide plate work 11 is hit twice by the ultrasonic processing horn 101 to form the recess 13, the distribution of variation in size is adjusted. When adjusting the distribution of the size of the recesses 13, the ultrasonic processing horn 101 is moved to a position different from the formation of the recesses 13, and then the ultrasonic processing horn 101 is moved to the light guide plate work 11. Make contact.

  That is, when forming the recess 13, the ultrasonic processing horn 101 starts processing from a position where the recess 13 is formed from the end of the light guide plate work 11, for example. Then, when the ultrasonic processing horn 101 is brought into contact with the light guide plate work 11, a recess group consisting of 144 recesses 13 is formed at a time. Thereafter, the ultrasonic processing horn 101 moves, for example, in the right direction, and forms a new recess group so as to be adjacent to the already formed recess group. At this time, the interval between the row of the leftmost recesses 13 of the already formed recess group and the row of the rightmost recesses 13 of the newly formed recess group is substantially the same as the sense between the other recesses 13. It becomes an interval. That is, after forming the concave group, the ultrasonic processing horn 101 moves a distance corresponding to one pitch corresponding to the width of the concave group to form a new concave group. By repeatedly executing these operations, the recesses 13 are formed on the surface of the light guide plate work 11 at equal intervals in the horizontal and vertical directions. Further, when the ultrasonic processing horn 101 reaches the right end of the light guide plate work 11, the ultrasonic processing horn 101 moves downward by one pitch. The ultrasonic processing horn 101 performs processing while moving toward the left end. And thereby, the recessed part 13 formed in the surface of the light-guide plate workpiece | work 103 is distributed as shown in FIG. Regions A1, A2, A9, and A10 shown in the figure are regions for indicating a set of recesses 13 formed when the ultrasonic processing horn 101 is brought into contact with the light guide plate work 11 once. .

  Next, the ultrasonic processing horn 101 adjusts the variation in the size of the recess 13. Specifically, the ultrasonic processing horn 101 moves, for example, to the vicinity of the upper left of the light guide plate workpiece 103. At this time, the ultrasonic processing horn 101 is at a position where the newly formed recess 13 does not overlap the already formed recess 13 and a plurality of newly formed recess groups are already formed. It moves to the position which straddles the recess group. When the ultrasonic processing horn 101 comes into contact with the light guide plate work 103 and forms a new recess at such a position, the newly formed recess group is formed as shown in FIG. A group is formed with a shift of 1/2 pitch in the vertical and horizontal directions. And each newly formed recessed part 13 is formed in the center part of the four recessed parts 13 arranged so that a square may be formed among the already formed recessed parts 13. The ultrasonic processing horn 101 repeatedly forms the recess 13 by the same operation as described above. Thereby, the surface of the light-guide plate workpiece | work 11 will be in a state as shown in FIG. As shown in the figure, the density of dots in the concave portion 13 is relatively high in the central portion of the light guide plate work 11. When the diffusion plate 5 is arranged on one main surface of the light guide plate 3 formed in this way, light is emitted as shown in FIG. As is apparent from the figure, no light unevenness occurs on the surface of the light guide plate.

  The display board 7 is made of a plastic material having a predetermined translucency. Predetermined information is printed on the main surface of such a display board 7. The display plate 7 is arranged so that one main surface faces the other main surface of the diffusion plate 5. When the light diffused in the diffusion plate 5 enters one main surface of the display plate 7, the incident light passes through the display plate 7 and the other main surface of the display plate 7 emits light. Thereby, the visibility of the information printed on the display board 7 is improved.

  In addition to the above-described configuration, such a light-emitting signboard 1 is formed with an LED (Light Emitting Diode) array in the vicinity of one end face. At this time, the LED array may be formed along one end face of the light guide plate 3, or may be arranged along two opposing end faces. Further, when the LED array is formed along one end surface of the light guide plate 3, it is also possible to dispose a reflecting plate on the end surface facing the end surface. Thereby, the light intensity of the light-emitting signboard 1 can be kept constant. For example, when the light emitting sign 1 is hung on the ceiling or the like, the LED array can be formed along the end surface corresponding to the upper side of the light guide plate 3. Thereby, the wiring of the LED array can be easily performed, and it is not necessary to arrange various devices on the end surface corresponding to the bottom side of the light guide plate 3.

  According to experiments by the inventors, it has been found from the following experiment that the luminance of light emitted from a light guide plate having a recess formed on one main surface is about 1400 candela or more. Specifically, the inventors used an acrylic resin light guide plate having a width of 260 mm, a height of 110 mm, and a thickness of 5 mm, and arranged 30 LED elements along one end face in the width direction. And the pitch between each LED element was 8.25 mm. Then, a current of 20 mA per LED element was supplied to such an LED array at a direct current of 24V. At this time, the luminance of the central portion of the light guide plate 3 was 1420 candela, and the illuminance was 4970 LUX.

  As described above, according to the embodiment of the present invention, it is possible to prevent unevenness of light from occurring on the light emitting surface of the light emitting signboard 1 while maintaining a certain luminance or more.

  The present invention is not limited to the above-described embodiment, and each configuration can be changed as appropriate without departing from the spirit of the present invention.

It is a perspective view of the light emission type signboard concerning an embodiment. It is a perspective view of the light-guide plate with which the same light emission type signboard is provided. It is sectional drawing which shows the principal part of the same light-guide plate. It is sectional drawing which shows the principal part of the same light-guide plate. It is a top view which shows the principal part of the same light-guide plate. It is a top view which shows the principal part of the same light-guide plate. It is a top view which shows the principal part of the same light-guide plate. It is a top view which shows the same light-guide plate. It is the photograph of the light-guide plate image | photographed in the experimental result. It is a principal part perspective view of the horn for ultrasonic processing. It is a figure which shows the manufacturing process of the same light-guide plate. It is the photograph of the light-guide plate used conventionally.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Light-emitting signboard 3 Light guide plate 5 Diffusion plate 7 Display plate 9 Reflection plate 11 Light guide plate work 13 Concave part 101 Ultrasonic processing horn 103 Light guide plate work 105 Processing dot

Claims (2)

In the light guide plate manufacturing method for emitting light incident from the end face from the main surface,
A first forming step of forming a first recess group composed of a plurality of recesses for bringing a predetermined ultrasonic processing horn into contact with a main surface of the light guide plate and deflecting a traveling direction of light incident from the end surface;
A second forming step of forming a second concave group consisting of a plurality of concave portions for bringing the ultrasonic processing horn into contact with the main surface of the light guide plate and deflecting the traveling direction of the light incident from the end surface. ,
The method for manufacturing a light guide plate, wherein the second recess group is formed so as not to overlap the first recess group. The first forming step is a step of forming the plurality of first recess groups adjacent to each other by bringing the ultrasonic processing horn into contact with the main surface of the light guide plate a plurality of times.
The second forming step is a step of forming the second recess group so as to straddle a plurality of the first recess groups formed adjacent to each other among the plurality of first recess groups. The manufacturing method of Claim 1 characterized by these.