JP2010061905A - Illumination sheet, and method of manufacturing illumination device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an illumination sheet in which a light receiving part of a light guide sheet can be fixed certainly to an optimal position near the light source part of a circuit board. <P>SOLUTION: The illumination sheet includes: a light guide sheet which guides light and emits it from a first plane; and a carrier sheet 3 which is adhered to the first plane and suppresses bending of the light guide sheet. The light guide sheet has an adhesion part 23 which enables adhesion of the light guide sheet to the circuit board in the vicinity of a first side face crossing at right angles the first plane and a second plane on the second plane opposed to the first plane. The carrier sheet 3 is provided with a cut part 5 which is cut out in the longitudinal direction of the first side face and in the thickness direction of the carrier sheet 3, a first slit part 7 which is cut in a direction connecting a first portion 31a of a second side face 31 of the carrier sheet 3 located on the opposite side to the adhesion part 23 of the cut part 5 with the cut part 5, and a second slit part 8 which is cut in a direction connecting a second portion 31b of the second side face 31 with a prescribed spacing from the first portion 31a with the cut part 5. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a light guide sheet, and more particularly to an illumination sheet including a light guide sheet and a method for manufacturing an illumination device including the light guide sheet.

  An illumination device using a light guide sheet including an optical film, a dot pattern, and the like is used for illumination of a key sheet of a mobile phone having a demand for thinning, miniaturization, and high design. The illumination device guides light from a light source typified by an LED by an optical film, reflects the guided light at a dot pattern, emits the reflected light, and illuminates the key sheet from the back surface.

  A technique relating to a backlight structure of a liquid crystal display device is disclosed in Patent Document 1. This liquid crystal display device includes a box-shaped holding frame for storing a diffusion sheet, a light guide plate, and a reflector on the lower surface of the liquid crystal display device. The holding frame has an opening at the bottom in the side wall along the side wall. An LED provided in an FPC (Flexible Print Circuit) is inserted into the opening with a spacer sheet interposed therebetween. The liquid crystal display device of Patent Document 1 is characterized in that the spacer sheet has a plurality of cuts at positions where the LEDs are attached, and the LEDs are inserted into the cuts and then inserted into the openings. Since such a liquid crystal display device does not generate a gap around the LED due to the spacer sheet, it can be effectively used without leakage of the LED light.

Japanese Patent Laid-Open No. 2005-92000

  The manufacturing method of the illuminating device 110 which comprises the sheet | seat 100 for illumination relevant to a light guide sheet, and a light guide sheet is demonstrated. FIG. 1 is a partially enlarged view of the illumination sheet 100. 2 is a cross-sectional view taken along line A1-A2 of the illumination sheet 100 in FIG. Referring to FIGS. 1 and 2, the lighting sheet 100 includes a light guide sheet 2, a carrier sheet 3, a separator 4, and a cut portion 5. The illumination sheet 100 shows a state before being incorporated into a circuit board 9 described later.

  The light guide sheet 2 guides light from a light source typified by an LED entering from the side surface (for example, the side surface 24) of the light guide sheet 2, and emits light. The light guide sheet 2 includes an optical film 21, a dot pattern 22, and an adhesive portion 23. The optical film 21 guides light. The optical film 21 is a transparent or translucent thin sheet, and is formed of, for example, a material having high light guide properties such as acrylic resin, silicon resin, polycarbonate resin, or polyethylene terephthalate resin. The dot pattern 22 reflects light guided through the optical film. The reflected light is emitted from the surface of the light guide sheet 2 on which the dot pattern 22 is not applied. The dot pattern 22 is formed on the optical film 21 by a method such as printing. The adhesion part 23 adheres the light guide sheet 2 to the optimum position when the light guide sheet 2 is incorporated into the circuit board 9. A plurality of adhesive portions 23 may be included. At least one of the bonding portions 23 is disposed in the vicinity of the light receiving portion 25 described later. By disposing in the vicinity of the light receiving unit 25, the bonding unit 23 can more reliably fix the light receiving unit 25 to the optimal position of the circuit board 9.

  The carrier sheet 3 serves as a base material when the lighting sheet 100 is manufactured. An optical film 21, a dot pattern 22, an adhesive portion 23, and a separator 4 are formed on the carrier sheet 3. The carrier sheet 3 serves as a base material that makes the light guide sheet 2 difficult to bend when the light guide sheet 2 is incorporated into the circuit board 9. The carrier sheet 3 is peeled off from the light guide sheet 2 after the light guide sheet 2 is bonded to the optimum position of the circuit board 9.

  The separator 4 protects the adhesiveness of the adhesive portion 23 included in the light guide sheet 2. Therefore, the separator 4 is peeled off before the light guide sheet 2 is bonded to the circuit board 9.

  The cut portion 5 is cut from the surface of the separator 4 in the longitudinal direction (Y direction) of the side surface 24 and the side surface 31 and in the thickness direction (Z direction) of the lighting sheet 1 in the vicinity of the adhesive portion 23. It is a part. The term “cut” includes a state in which the light guide sheet 2, the carrier sheet 3, and the separator 4 are cut out in a planar shape having a width in the X direction, and a state in which the surface is not cut out. And The cut portion 5 is located on the opposite side of the dot pattern 22 with respect to the adhesive portion 23. The light guide sheet 2 and the separator 4 are cut by a cut portion 5. Of the cut surface of the light guide sheet 2 by the cut portion 5, the cross section on the side including the dot pattern 22 and the adhesive portion 23 becomes the light receiving portion 25. That is, in the light guide sheet 2 divided into two by the notch part 5, the part including the dot pattern 22 and the adhesive part 23 is a part incorporated in the circuit board 9. The part not including the dot pattern 22 and the bonding part 23 becomes the non-mounting part 6 that is not incorporated. The carrier sheet 3 is cut in the thickness direction by the cut portion 5 but is not cut.

  FIG. 3 is a diagram illustrating a method for manufacturing the lighting device 110 in which the conductor sheet 2 included in the lighting sheet 100 is attached to the circuit board 9. With reference to FIG. 3, the manufacturing method of the illuminating device 110 is demonstrated. The circuit board 9 is exemplified by a resin board such as glass epoxy or a flexible board that can be bent, and has a light source unit 91 such as an LED on the surface. First, the separator 4 that protected the adhesive portion 23 from the lighting sheet 100 is peeled off. And the surface containing the adhesion part 23 of the sheet | seat 100 for illumination and the surface containing the light source part 91 of the circuit board 9 oppose ((a) of FIG. 3).

  The lighting sheet 100 from which the separator 4 has been peeled is pressed from the carrier sheet 3 side. At this time, the location where the carrier sheet 3 is pressed is preferably a location where the adhesive portion 23 can be sufficiently pressed. When the illumination sheet 100 approaches the circuit board 9, the non-mounting part 6 comes into contact with the light source part 91. Further, when the illumination sheet 100 is pressed from the carrier sheet 3 side, the non-mounting portion 6 is in a state of riding on the light source portion 91. At this time, it is assumed that another bonding portion of the lighting sheet 100 (not shown) is bonded to the circuit board 9 by pressing. The illumination sheet 100 bends from the portion of the carrier sheet 3 that is thinned by the cut portion 5, but the light receiving portion 25 of the light guide sheet 2 is not lowered to the optimum position 26 due to the repulsive force of the carrier sheet 3. Therefore, the bonding portion 23 cannot be bonded to the circuit board 9 ((b) of FIG. 3).

  The carrier sheet 3 is peeled from the light guide sheet 2 without the circuit board 9 and the bonding portion 23 being bonded. In the lighting device 110 manufactured in this way, there is a high possibility that the light receiving portion 25 of the light guide sheet 2 is shifted from the optimum position 26 of the circuit board 9 ((c) in FIG. 3). Therefore, in the method of manufacturing the lighting device 110 using the lighting sheet 100, the light received by the conductor sheet 2 is insufficient or unstable, and it is difficult to stably illuminate the lighting device 110.

  In the illuminating device including the light guide sheet 2, the position of the light receiving unit 25 of the light guide sheet 2 is securely fixed at the optimum position 26 on the circuit board 9 in order to receive the light of the light source unit 91 of the circuit board 9. It is important that If the positions of the light receiving unit 25 and the light source unit 91 are shifted, the light guide sheet 2 cannot receive light efficiently and cannot sufficiently illuminate the object. One of the causes that the positions of the light receiving unit 25 and the light source unit 91 are displaced is the adhesion failure of the light guide sheet 2 in the vicinity of the light source unit 91 in the process of attaching the light guide sheet 2 to the circuit board 9, and improvement is required. ing.

  The objective of this invention provides the sheet | seat for illumination which can fix reliably the light-receiving part of a light guide sheet to the optimal position of the light source part vicinity of a circuit board so that the illuminating device which comprises a light guide sheet may illuminate stably.

The lighting sheet of the present invention includes a light guide sheet that guides light and emits light from the first plane, and a carrier sheet that adheres to the first plane and suppresses the deflection of the light guide sheet. The light guide sheet includes an adhesive portion that allows the light guide sheet to be bonded to the circuit board in the vicinity of the first plane and the first side surface orthogonal to the second plane on the second plane facing the first plane. The carrier sheet has a cut portion cut in the longitudinal direction of the first side surface and in the thickness direction of the carrier sheet, and the first of the second side surface of the carrier sheet positioned on the opposite side of the adhesive portion with respect to the cut portion. Cut in the direction connecting the first slit part cut in the direction connecting the part and the cut part, and the second part on the second side and the cut part spaced apart from the first part. A second slit portion. The predetermined interval is the length of the light source unit in the longitudinal direction when the light guide sheet is bonded to the circuit substrate so that the light from the light source unit of the circuit substrate can be received.
In such an illumination sheet, the first slit portion and the second slit portion facilitate bending at the cut portion. The ease of bending in the cut portion of the illumination sheet reduces adhesion failure due to contact between the light source portion and the illumination sheet when adhered to the circuit board, and improves adhesion.

  The illumination sheet of the present invention can securely fix the light receiving portion of the light guide sheet at the optimum position of the circuit board. Therefore, the illumination device manufactured using the illumination sheet of the present invention does not shift the position of the light receiving part of the light guide sheet and the light source part of the circuit board, so the light guide sheet efficiently takes in the light of the light source part, The object can be illuminated stably.

  Hereinafter, an illumination sheet 1 according to an embodiment of the present invention will be described with reference to the accompanying drawings.

  A first embodiment of the present invention will be described. FIG. 4 is a partially enlarged view of the lighting sheet 1 according to the first embodiment of the present invention. 5 is a B1-B2 cross-sectional view of the lighting sheet 1 of the present invention shown in FIG. Referring to FIGS. 4 and 5, the lighting sheet 1 includes a light guide sheet 2, a carrier sheet 3, a separator 4, a cut portion 5, a slit 7, and a slit 8. The lighting sheet 1 shows a state before being incorporated into the circuit board 9. In the lighting sheet 1 of the present invention, the same reference numerals are used for the same configuration as the lighting sheet 100 described above. When the illumination sheet 1 of the present invention and the illumination sheet 100 described above are compared, the difference is that the slit 7 and the slit 8 are provided. Since the other configuration is the same, the description is omitted.

  The slit 7 is a site where the light guide sheet 2 and the carrier sheet 3 are cut together in the thickness direction (Z direction). The separator 4 may also be cut at the same time. It should be noted that the slit 7 being cut includes a state in which a part of the light guide sheet 2 and the carrier sheet 3 is cut out as shown in FIG. 4 and a state in which the surface is not cut out. The slit 7 is cut in a direction in which the cut portion 5 is connected to the side surface 24 a of the light guide sheet 2 and the side surface 31 a of the carrier sheet 3, which are located on the opposite side of the cut portion 5 from the adhesive portion 23. . The side surface 24 a indicates an arbitrary part included in the side surface 24 of the light guide sheet 2. The side surface 31 a indicates an arbitrary part included in the side surface 31 of the carrier sheet 3. The side surface 24a and the side surface 31a are shown at the same position in FIG. The slit 7 includes a slit 7a and a slit extension 7b. The slit 7a shows the part from the side 24a and the side 31a to the notch part 5, and the slit extension part 7b shows the part beyond the notch part 5. FIG. In addition, although it is preferable that the slit 7 is a direction which connects the side surface 24a and the side surface 31a, and the notch part 5 so that it may orthogonally cross with respect to the notch part 5, it is not restricted to this.

The slit 8 is a part cut in the same manner as the slit 7. The slit 8 is cut in a direction in which the cut portion 5 is connected to the side surface 24 b of the light guide sheet 2 and the side surface 31 b of the carrier sheet 3, which are located on the opposite side of the cut portion 5 from the adhesive portion 23. . The side surface 24b and the side surface 31b are shown at the same position in FIG. The interval between the side surface 24a and the side surface 24b and the interval between the side surface 31b and the side surface 31a are predetermined intervals in the Y direction. The predetermined interval is the length of the light source unit 91 in the Y direction when the light guide sheet 2 is bonded to the circuit substrate 9 so that the light of the light source unit 91 of the circuit substrate 9 can be received appropriately. That is, the light source unit 91 is sandwiched between the slit 7 and the slit 8. Similarly to the slit 7, the slit 8 includes a slit 8 a and a slit extension 8 b. The slit 8a indicates a portion from the side surface 24b and the side surface 31b to the cut portion 5, and the slit extension portion 8b indicates a portion beyond the cut portion 5.
A plurality of slits similar to the slits 7 and 8 may be included in the predetermined interval.

  FIG. 6 is a view showing a method of manufacturing the lighting device 10 in which the conductor sheet 2 included in the lighting sheet 1 of the present invention is attached to the circuit board 9. With reference to FIG. 6, the manufacturing method of the illuminating device 10 of this invention is demonstrated. First, the separator 4 that has protected the adhesive portion 23 from the lighting sheet 1 is peeled off. In the illumination sheet 1 and the circuit board 9 from which the separator 4 has been peeled off, the surface of the illumination sheet 1 that includes the adhesive portion 23 and the surface of the circuit substrate 9 that includes the light source unit 91 face each other. And a position is adjusted so that the light source part 91 of the circuit board 9 may be arrange | positioned between the slit 7 and the slit 8 ((a) of FIG. 6).

  The lighting sheet 1 from which the separator 4 has been peeled is pressed from the carrier sheet 3 side. At this time, the location where the carrier sheet 3 is pressed is preferably a location where the adhesive portion 23 can be sufficiently pressed. When the illumination sheet 1 approaches the circuit board 9, the non-mounting part 6 comes into contact with the light source part 91. Further, when the illumination sheet 1 is pressed from the carrier sheet 3 side, the non-mounting portion 6 is in a state of riding on the light source portion 91, but unlike the illumination sheet 100 described above, the bonding portion 23 is connected to the circuit board 9. Glue. The light receiving part 25 position of the light guide sheet 2 where the adhesive part 23 is bonded to the circuit board 9 is the optimum position 26. Since the lighting sheet 1 of the present invention has the slits 7 and the slits 8, the repulsive force of the carrier sheet 3 is suppressed, so that the carrier sheet 3 is easily bent from the portion where the cuts 5 make it thinner. Therefore, the bonding portion 23 of the light guide sheet 2 can be bonded to the circuit board 9. In the carrier sheet 3, the portion that rides on the light source unit 91 and is bent is a portion between the slit 7 and the slit 8 (FIG. 6B). The slit 7 and the slit 8 include the slit extension part 7b and the slit extension part 8b, thereby increasing the effect of ease of bending. The slit extension portion 7b and the slit extension portion 8b make the carrier sheet 3 more easily bent when cut long in the X direction, but preferably do not exceed the adhesive portion 23 in the X direction. However, the slit 7 and the slit 8 can also cause the carrier sheet 3 to be easily bent only by the slit 7a and the slit 8a. Further, a plurality of similar slits may be included between the slit 7 and the slit 8. The carrier sheet 3 includes a plurality of slits so that the carrier sheet 3 is more easily bent.

  Based on the pressure from the carrier sheet 3 side, the adhesive portion 23 is sufficiently adhered to the circuit board 9, and then the carrier sheet 3 is peeled from the light guide sheet 2. In the illuminating device 10 according to the present invention thus manufactured, the light receiving portion 25 of the light guide sheet 2 is in the optimum position 26, and the light receiving portion 25 and the light source portion 91 of the circuit board 9 are fixed without being displaced. . That is, since the conductor sheet 2 can receive sufficient light, the illuminating device 10 can stably illuminate ((c) in FIG. 6).

  FIG. 7 is a cross-sectional view of FIG. 6C as viewed from the Z direction. Referring to FIG. 7, when the light guide sheet 2 includes a slit extension portion 7 b and a slit extension portion 8 b, the light guide sheet 2 remains in the mounted light guide sheet 2.

  The lighting sheet 1 according to the first embodiment of the present invention can securely fix the light guide sheet 2 at the optimum position 26 of the circuit board 9. This is because the carrier sheet 3 necessary for attaching the light guide sheet 2 has the slits 7 and 8 so that the carrier sheet 3 can be easily bent, so that the adhesive portion 23 and the circuit board 9 can be pressed and adhered without difficulty. It is. That is, in the illumination sheet 1 according to the present invention, since the positions of the light receiving unit 25 and the light source unit 91 of the light guide sheet 2 do not shift, the light guide sheet 2 efficiently takes in the light of the light source unit 91 and stabilizes the object. And can be illuminated. Further, since no gap is generated between the light guide sheet 2 and the circuit board 9, it is possible to prevent foreign matters from being mixed and to stabilize the quality.

  A second embodiment of the present invention will be described. The lighting sheet 1 according to the second embodiment of the present invention is the same partial enlarged view as FIG. 4 as in the first embodiment. FIG. 8 is a cross-sectional view taken along the line B1-B2 shown in FIG. 4 of the lighting sheet 1 according to the second embodiment of the present invention. Referring to FIGS. 8 and 4, the lighting sheet 1 includes a light guide sheet 2, a carrier sheet 3, a separator 4, a cut portion 5, a slit 7, and a slit 8. The difference from the first embodiment is that the light guide sheet 2 does not include a portion included in the non-mounting portion 6 cut by the cut portion 5. Since the other configuration is the same, the description is omitted. In the second embodiment, the same reference numerals are used for the same configurations as those in the first embodiment.

  FIG. 9 is a diagram illustrating a step in the method of manufacturing the lighting device 10 using the lighting sheet 1 according to the second embodiment of the present invention. FIG. 9 shows a manufacturing process corresponding to FIG. 6B according to the first embodiment of the present invention. Referring to FIG. 9, lighting sheet 1 from which separator 4 has been peeled is pressed from the side of carrier sheet 3. At this time, the location where the carrier sheet 3 is pressed is preferably a location where the adhesive portion 23 can be sufficiently pressed. When the illumination sheet 1 approaches the circuit board 9, the non-mounting part 6 comes into contact with the light source part 91. Further, when the lighting sheet 1 is pressed from the carrier sheet 3 side, the bonding portion 23 is bonded to the circuit board 9, and the non-mounting portion 6 rides on the light source portion 91. At this time, since the carrier sheet 3 has the slit 7 and the slit 8, the carrier sheet 3 has an effect of being easily bent from the portion thinned by the cut portion 5. Furthermore, in the second embodiment of the present invention, the light guide sheet 2 is not included in the non-mounting portion 6, so that even when the non-mounting portion 6 rides on the light source portion 91, the bending angle of the carrier sheet 3 is It is moderate. That is, the second embodiment of the present invention has an effect that the repulsive force of the carrier sheet 3 can be suppressed more than that of the first embodiment.

  The lighting sheet 1 according to the second embodiment of the present invention can securely fix the light guide sheet 2 to the optimum position 26 of the circuit board 9 with a smaller load. This is because the light guide sheet 2 of the non-mounting portion 6 is removed in advance, and the bending angle of the carrier sheet 3 is made gentle, so that the repulsive force of the carrier sheet 3 is small. That is, the lighting sheet 1 according to the second embodiment of the present invention has an effect of reducing the manufacturing load of the lighting device 10 and improving the manufacturing efficiency.

  It is assumed that various devices for manufacturing the lighting device 10 according to the present invention use well-known techniques.

FIG. 1 is a partially enlarged view of the lighting sheet 100. 2 is a cross-sectional view taken along line A1-A2 of the illumination sheet 100 in FIG. FIG. 3 is a diagram illustrating a method for manufacturing the lighting device 110 in which the conductor sheet 2 and the circuit board 9 included in the lighting sheet 100 are attached. FIG. 4 is a partially enlarged view of the lighting sheet 1 according to the first embodiment of the present invention. 5 is a B1-B2 cross-sectional view of the lighting sheet 1 of the present invention shown in FIG. FIG. 6 is a diagram showing a method of manufacturing the lighting device 10 in which the conductor sheet 2 and the circuit board 9 included in the lighting sheet 1 of the present invention are attached. FIG. 7 is a cross-sectional view of FIG. 6C as viewed from the Z direction. FIG. 8 is a cross-sectional view taken along the line B1-B2 shown in FIG. 4 of the lighting sheet 1 according to the second embodiment of the present invention. FIG. 9 is a diagram illustrating a step in the method of manufacturing the lighting device 10 using the lighting sheet 1 according to the second embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Illumination sheet 2 Light guide sheet 3 Carrier sheet 4 Separator 5 Notch part 6 Non-mounting part 7 Slit 7a Slit 7b Slit extension part 8 Slit 8a Slit 8b Slit extension part 9 Circuit board 10 Illumination device 21 Optical film 22 Dot pattern 23 Bonding part 24 Side face 24a Side face 24b Side face 25 Light receiving part 31 Side face 31a Side face 31b Side face 91 Light source part 100 Illuminating sheet 110 Illuminating device

Claims (4)

A light guide sheet that guides light and emits it from the first plane;
A carrier sheet that adheres to the first plane and suppresses bending of the light guide sheet;
The light guide sheet is
An adhesive portion on the second plane facing the first plane, in the vicinity of the first side surface orthogonal to the first plane and the second plane;
The carrier sheet is
A cut portion cut in the longitudinal direction of the first side surface and in the thickness direction of the carrier sheet;
A first slit portion cut in a direction connecting the first portion of the second side surface of the carrier sheet located on the opposite side to the adhesive portion with respect to the cut portion, and the cut portion;
A second slit part cut in a direction connecting the second part of the second side face spaced apart from the first part and the cut part, and the predetermined distance is The illumination sheet, which is the length of the light source section in the longitudinal direction when the light guide sheet is bonded to the circuit board so as to receive light from the light source section of the circuit board. The lighting sheet according to claim 1,
The lighting sheet further comprising a third slit portion cut in a direction connecting the third portion of the first side surface portion included between the first portion and the second portion and the cut portion. . The lighting sheet according to claim 1 or 2,
The carrier sheet is
At least one of the first slit part and the second slit part includes a first slit extension part cut beyond the notch part,
The light guide sheet is
An illumination sheet including a second slit extension at a position overlapping the first slit extension. The step of causing the second plane of the lighting sheet according to any one of claims 1 to 3 to face the surface including the light source part of the circuit board,
Aligning the position of the light source unit between the first part and the second part so that the length of the light source part is contained;
Adhering the adhesive portion in the vicinity of the light source portion of the circuit board;
And a step of peeling the carrier sheet from the lighting sheet.

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