WO2019142618A1 - Planar light source device production method, planar light source device, display device and electronic machine - Google Patents

Planar light source device production method, planar light source device, display device and electronic machine Download PDF

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Publication number
WO2019142618A1
WO2019142618A1 PCT/JP2018/047573 JP2018047573W WO2019142618A1 WO 2019142618 A1 WO2019142618 A1 WO 2019142618A1 JP 2018047573 W JP2018047573 W JP 2018047573W WO 2019142618 A1 WO2019142618 A1 WO 2019142618A1
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WO
WIPO (PCT)
Prior art keywords
adhesive film
guide plate
light guide
light source
fpc
Prior art date
Application number
PCT/JP2018/047573
Other languages
French (fr)
Japanese (ja)
Inventor
幸太 米澤
直紀 奥冨
潤 前嶋
義貴 武内
義治 杉山
彰 永尾
和英 廣田
恵一 木下
Original Assignee
オムロン株式会社
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Filing date
Publication date
Application filed by オムロン株式会社 filed Critical オムロン株式会社
Publication of WO2019142618A1 publication Critical patent/WO2019142618A1/en

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21S—NON-PORTABLE LIGHTING DEVICES; SYSTEMS THEREOF; VEHICLE LIGHTING DEVICES SPECIALLY ADAPTED FOR VEHICLE EXTERIORS
    • F21S2/00—Systems of lighting devices, not provided for in main groups F21S4/00 - F21S10/00 or F21S19/00, e.g. of modular construction
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings

Definitions

  • the present invention relates to a method of manufacturing a surface light source device, a surface light source device, a display device, and an electronic device.
  • FIG. 14 is a cross-sectional view of the surface light source device 100.
  • the surface light source device 100 includes a light guide plate 101 and a light source 102 disposed to face the light incident surface 101A of the light guide plate 101.
  • a frame 103 is disposed to surround the side surface and the lower surface of the light guide plate 101.
  • a flexible printed circuit (hereinafter also referred to as “FPC”) 104 is disposed on the light guide plate 101 and the light source 102.
  • a diffusion sheet 105, a plurality of prism sheets 106, and a light shielding double-sided sheet 107 are sequentially placed on the light exit surface 101B side of the light guide plate 101.
  • a reflective sheet 108 is disposed on the bottom of the frame 103.
  • the FPC 104 is fixed to the light guide plate 101 and the frame 103 using the double-sided adhesive tape 110.
  • the adhesive strength of the double-sided adhesive tape 110 may be reduced by exposing the double-sided adhesive tape 110 to the atmosphere. Due to the recent needs for narrowing the frame, the width of the frame 103 is reduced, and the bonding area between the light guide plate 101 and the double-sided tape 110 is also reduced.
  • the adhesive strength of the double-sided adhesive tape 110 has a trade-off relationship with the adhesive area of the double-sided adhesive tape 110. Therefore, when the width of the frame 103 is reduced, the adhesive strength of the double-sided tape 110 is reduced, and when the adhesion area of the light guide plate 101 and the double-sided tape 110 is reduced, the adhesive strength of the double-sided tape 110 is reduced. When the adhesive strength of the double-sided adhesive tape 110 is lowered, the double-sided adhesive tape 110 may peel off from the light guide plate 101 or the double-sided adhesive tape 110 may peel off from the frame 103.
  • FIG. 15 is a schematic view when the liquid crystal display 111 is mounted on the surface light source device 100.
  • the liquid crystal display 111 has a glass 112, an upper polarizing plate 113 and a lower polarizing plate 114.
  • the FPC 104 is fixed to the lower polarizing plate 114, and the surface light source device 100 and the glass 112 are connected by the liquid crystal main FPC 115. Since the liquid crystal main FPC 115 has high resilience, the FPC 104 is pulled toward the liquid crystal display 111.
  • the FPC 104 pops out of the surface light source device 100 and causes the light leakage of the surface light source device 100.
  • an object of the present invention is to improve the adhesion between the light guide plate and the flexible printed circuit and to improve the adhesion between the frame and the flexible printed circuit.
  • the present invention adopts the following means in order to solve the above problems. That is, the present invention includes a step of disposing an adhesive film on a substrate on which a light source is mounted, a first pressure bonding step of pressure-bonding the adhesive film to the substrate in a state where the adhesive film is heated by heating the adhesive film, And a second pressure-bonding step of pressure-adhering the adhesive film to the substrate and the light guide plate in a step of bringing the adhesive film into contact with the light guide plate, and heating the adhesive film to melt the adhesive film.
  • the adhesive film By heating the adhesive film, the adhesive film is melted, and the adhesive strength of the adhesive film is increased. After the adhesive film is melted, the adhesive film is cooled to harden the adhesive film.
  • the adhesive film is heated to melt the adhesive film, and then the adhesive film is pressure-bonded to the substrate, the light guide plate and the frame. It is fixed. Therefore, peeling of the adhesive film from the light guide plate is suppressed, and peeling of the adhesive film from the frame is suppressed. Thereby, the adhesion between the substrate and the light guide plate is improved, and the adhesion between the substrate and the frame is improved.
  • the heating temperature in the third pressure bonding step is higher than the heating temperature in the first pressure bonding step and the heating temperature in the second pressure bonding step.
  • the adhesive strength of the adhesive film after the third pressure bonding step is performed is after the first pressure bonding step is performed and before the second pressure bonding step is performed.
  • the adhesive strength of the adhesive film is larger than the adhesive strength of the adhesive film before the third pressure bonding step is performed after the second pressure bonding step is performed.
  • a pressure mechanism having a plurality of adhesive films and having a plurality of protrusions in at least one of the first pressure bonding process, the second pressure bonding process, and the third pressure bonding process
  • the substrate is pressurized by using, and the pitch of the plurality of protrusions corresponds to the pitch of the plurality of adhesive films.
  • a light guide plate having a light incident surface on which light is incident on a side surface, a light source disposed opposite to the light incident surface of the light guide plate, a substrate mounted with the light source, a light guide plate, a light source
  • a surface light source device comprising: a frame for housing a substrate; and an adhesive film disposed between the light guide plate and the substrate and between the substrate and the frame and thermocompression-bonded to the light guide plate, the substrate and the frame.
  • a display device according to the present invention includes the surface light source device according to the present invention, and a display panel that receives light emitted from the surface light source device.
  • An electronic device according to the present invention includes the display device according to the present invention.
  • the adhesion between the light guide plate and the flexible printed circuit can be improved, and the adhesion between the frame and the flexible printed circuit can be improved.
  • FIG. 1A is a view showing an example of a method of manufacturing a surface light source device according to an embodiment.
  • FIG. 1B is a view showing an example of the adhesive film according to the embodiment.
  • FIG. 2 is a perspective view illustrating the configuration of the liquid crystal display device according to the embodiment.
  • FIG. 3 is a perspective view illustrating the configuration of the surface light source device according to the embodiment.
  • FIG. 4 is a cross-sectional view illustrating the configuration of the surface light source device according to the embodiment.
  • FIG. 5 is an explanatory view of the step of pressure bonding the adhesive film to the FPC.
  • FIG. 6 is an explanatory view of the step of pressure bonding the adhesive film to the FPC.
  • FIG. 7 is an explanatory view of the step of pressure bonding the adhesive film to the FPC.
  • FIG. 8 is an explanatory view of a process of pressure bonding the adhesive film to the FPC and the light guide plate.
  • FIG. 9 is an explanatory view of a process of pressure bonding the adhesive film to the FPC and the light guide plate.
  • FIG. 10 is an explanatory view of a process of pressure bonding the adhesive film to the FPC, the light guide plate and the frame.
  • FIG. 11 is an explanatory view of a process of pressure bonding the adhesive film to the FPC, the light guide plate and the frame.
  • FIG. 12 is a comparison diagram of the shear strength in Comparative Example 1 and the shear strength in Example 1.
  • FIG. 13 is a comparison diagram of the peel strengths in Comparative Examples 2 and 3 and the peel strength in Example 2.
  • FIG. 14 is a cross-sectional view of a surface light source device.
  • FIG. 15 is a schematic view when the liquid crystal display is mounted on the surface light source device.
  • display device is described as a liquid crystal display device
  • surface light source device is described as a backlight unit of a liquid crystal display device.
  • the “surface light source device” may be used in applications other than a backlight unit, such as a front light disposed on the front of a display device or a display device made of electronic paper.
  • FIG. 1A is a view showing an example of a method of manufacturing a surface light source device according to an embodiment.
  • the process shown by dotted line A in FIG. 1A will be described.
  • the adhesive film 12 is disposed on the FPC 11, and the adhesive film 12 is crimped to the FPC 11 in a state where the adhesive film 12 is heated to melt the adhesive film 12.
  • the step of pressing the adhesive film 12 to the FPC 11 in a state in which the adhesive film 12 is heated by heating the adhesive film 12 is an example of a first pressure bonding step.
  • a light source is mounted on the FPC 11.
  • the FPC 11 is an example of a substrate. In the example shown in FIG.
  • the plurality of adhesive films 12 are disposed on the FPC 11 in a state where the plurality of adhesive films 12 are attached to the release paper 21.
  • the plurality of adhesive films 12 may be connected to each other without being limited to the example shown in FIG. 1A.
  • the adhesive film 12 may be strip-shaped. In the example shown in FIG. 1B, two strip-like adhesive films 12 are attached to the release paper 21.
  • the strip-like adhesive film 12 shown in FIG. 1B is used, the strip-like adhesive film 12 is disposed on the FPC 11 in a state where the strip-like adhesive film 12 is attached to the release paper 21.
  • the adhesive film 12 As the adhesive film 12 is heated, the adhesive film 12 is melted and the adhesive strength of the adhesive film 12 is increased. After the adhesive film 12 is melted, the adhesive film 12 is cooled to harden the adhesive film 12. By curing the adhesive film 12 after the adhesive film 12 is melted, the adhesive strength of the adhesive film 12 is maintained. As the heating temperature of the adhesive film 12 increases, the adhesive strength of the adhesive film 12 increases.
  • the process shown by dotted line B in FIG. 1A will be described. Before the process shown by the dotted line A in FIG. 1A is performed, the release paper 21 is peeled off from the adhesive film 12. In the process shown by the dotted line B in FIG. 1A, the FPC 11 is placed on the light guide plate 13 to bring the adhesive film 12 into contact with the light guide plate 13. In the process shown by the dotted line B in FIG. 1A, the adhesive film 12 is pressure-bonded to the FPC 11 and the light guide plate 13 in a state where the adhesive film 12 is heated and melted.
  • the step of pressure bonding the adhesive film 12 to the FPC 11 and the light guide plate 13 in a state in which the adhesive film 12 is heated by heating the adhesive film 12 is an example of a second pressure bonding process.
  • the process shown by dotted line C in FIG. 1A will be described.
  • the FPC 11, the adhesive film 12 and the light guide plate 13 are disposed in the frame 14 to bring the adhesive film 12 into contact with the frame 14.
  • the adhesive film 12 is pressure-bonded to the FPC 11, the light guide plate 13 and the frame 14 in a state where the adhesive film 12 is heated and melted.
  • the step of pressure-bonding the adhesive film 12 to the FPC 11, the light guide plate 13 and the frame 14 in a state in which the adhesive film 12 is heated by heating the adhesive film 12 is an example of a third pressure-bonding step.
  • the heating temperature in the process shown by the dotted line C in FIG. 1A is higher than the heating temperature in the process shown by the dotted line A in FIG. 1A and higher than the heating temperature in the process shown by the dotted line B in FIG.
  • the adhesive film 12 is pressure-bonded to the FPC 11 and the light guide plate 13 in a state where the adhesive film 12 is heated and melted.
  • the FPC 11 and the light guide plate 13 are bonded to each other, and the FPC 11 is fixed to the light guide plate 13. Since the FPC 11 is fixed to the light guide plate 13, when the FPC 11 and the light guide plate 13 are arranged in the frame 14 in the process shown by the dotted line C in FIG. 1A, positional deviation between the FPC 11 and the light guide plate 13 is avoided.
  • the adhesive film 12 is heated in the state of heating the adhesive film 12;
  • the light guide plate 13 and the frame 14 are crimped.
  • the FPC 11 and the light guide plate 13 are bonded to each other, the FPC 11 is fixed to the light guide plate 13, and the FPC 11 and the frame 14 are bonded to each other, and the FPC 11 is fixed to the frame 14.
  • the adhesive film 12 is heated to melt the adhesive film 12, the adhesive film 12 is pressure-bonded to the FPC 11, the light guide plate 13 and the frame 14, so that the FPC 11 comprises the light guide plate 13 and the frame in a state where the adhesive strength of the adhesive film 12 is large.
  • FIG. 2 is a perspective view illustrating the configuration of the liquid crystal display device according to the embodiment.
  • the liquid crystal display device includes a surface light source device 1 disposed as a backlight unit, and a display panel 2 that receives light emitted from the surface light source device 1.
  • the display panel 2 displays an image by applying a voltage to the liquid crystal sandwiched between the glass plates to increase or decrease the light transmittance.
  • the display panel 2 side may be described as the upper surface side, and the opposite surface side may be described as the lower surface side.
  • such a liquid crystal display device can be mounted on various electronic devices.
  • a smartphone, a digital camera, a tablet terminal, an electronic book, a wearable device, a car navigation device, an electronic dictionary, an electronic advertisement board, etc. can be illustrated as an electronic device provided with such a liquid crystal display device.
  • FIG. 3 is a perspective view illustrating the configuration of the surface light source device 1 according to the embodiment.
  • FIG. 4 is a cross-sectional view illustrating the configuration of the surface light source device 1 according to the embodiment.
  • the surface light source device 1 according to the embodiment includes an FPC 11, a plurality of adhesive films 12, a light guide plate 13, a frame 14, and a plurality of light sources 15.
  • the surface light source device 1 includes the diffusion sheet 16, the prism sheet 17 and the light shielding double-sided tape 18 sequentially mounted on the upper surface side of the light guide plate 13, and the reflection sheet 19 disposed on the lower surface side of the light guide plate 13.
  • the lower surface of the light guide plate 13 is a surface opposite to the upper surface of the light guide plate 13.
  • the FPC 11 is configured by providing a wiring with a conductor foil on a flexible insulating film base material and adhering a cover lay or resin (photosensitive resin), which is an insulating film for protection, on the surface. It is a wiring board. Wiring is provided on the FPC 11. The wiring of the FPC 11 is used to supply power to the light source 15 or the like.
  • the adhesive film 12 is disposed on the lower surface or the like of the FPC 11 and fixes the FPC 11 to the light guide plate 13 and the frame 14. The lower surface of the FPC 11 faces the upper surface of the light guide plate 13.
  • the adhesive film 12 is disposed between the FPC 11 and the light guide plate 13 and between the FPC 11 and the frame 14.
  • the adhesive film 12 is thermocompression-bonded to the FPC 11, the light guide plate 13 and the frame 14.
  • the light guide plate 13 is substantially flat and made of a translucent material such as polycarbonate resin and polymethyl methacrylate resin.
  • the light guide plate 13 has a light entrance surface 13A and a light exit surface 13B.
  • the light guide plate 13 has a light incident surface 13A on the side surface and a light exit surface 13B on the upper surface orthogonal to the side surface.
  • the light emitted from the light source 15 is incident on the light incident surface 13A of the light guide plate 13.
  • the light exit surface 13 B of the light guide plate 13 emits the light incident from the light source 15 into the light guide plate 13.
  • the light exit surface 13 B of the light guide plate 13 is a surface facing the display panel 2.
  • the light guide plate 13 guides the light incident from the light source 15 into the light guide plate 13 to the light exit surface 13B, and the whole or a part of the light exit surface 13B is illuminated.
  • the light guide plate 13 may include a light guide plate main body and a light introducing portion which is higher than the height of the light guide plate main body. The light emitted from the light source 15 efficiently enters the light guide plate main body from the light introducing portion, and the light use efficiency of the light guide plate 13 is improved. Since the light guide plate main body is thinner than the light introducing portion, the reduction in thickness of the surface light source device 1 is improved, and the reduction in thickness of the liquid crystal display device including the surface light source device 1 is improved.
  • the light guide plate 13 according to the embodiment may have a flat plate shape without the light introducing portion.
  • the frame 14 accommodates the FPC 11, the adhesive film 12, the light guide plate 13, the light source 15, the diffusion sheet 16, the prism sheet 17, and the reflection sheet 19.
  • the frame 14 may be a frame (frame-like member) having a frame surrounding the light guide plate 13 or a box (box-like member having a frame surrounding the light guide plate 13 and a bottom plate on which the frame is provided) ) May be.
  • the frame may be formed by four side wall members, a circular side wall member having an opening, or an elliptical side wall member having an opening. Further, the corner portions of the side wall members on the four sides of the frame may have a right-angled shape, and the corner portions of the side wall members on the four sides of the frame may have an R shape.
  • the light source 15 is disposed to face the light incident surface 13 A of the light guide plate 13.
  • the light source 15 emits white light from the fluorescent unit.
  • the light source 15 is, for example, an LED package, but a light source other than the LED package may be used.
  • the light source 15 is provided on the FPC 11 and receives power supply from the FPC 11 to drive and light it.
  • the light source 15 is mounted on the FPC 11 so that the light emitting surface of the light source 15 faces the light incident surface 13A of the light guide plate 13.
  • the light source 15 is formed by sealing an LED chip, which is a light emitting element, with a translucent resin (resin layer) containing a phosphor.
  • a phosphor layer may be disposed on the light emitting surface 13 B of the light guide plate 13 without disposing a phosphor on the LED chip, or a phosphor layer may be disposed on the reflective sheet 19.
  • LED light sources other than white may be used as the light source 15.
  • a plurality of light sources 15 may be mounted on the FPC 11 in a row at regular intervals.
  • a diffusion sheet 16 is disposed on the light exit surface 13 ⁇ / b> B of the light guide plate 13, and one or two prism sheets 17 are disposed on the diffusion sheet 16.
  • the diffusion sheet 16 is a semitransparent resin film, and diffuses the light emitted from the light exit surface 13B of the light guide plate 13 to widen the directivity characteristic of the light.
  • the prism sheet 17 is a transparent resin film on the upper surface of which a fine pattern in the form of a triangular prism is formed, and condenses the light diffused by the diffusion sheet 16 when the surface light source device 1 is viewed from the upper surface Increase the brightness.
  • the light shielding double-sided tape 18 is a black adhesive tape whose upper and lower surfaces are adhesive surfaces.
  • the light shielding double-sided tape 18 has a frame shape (ring shape) having an opening.
  • the light shielding double-sided tape 18 is disposed along the outer peripheral portion of the frame 14 to suppress the leakage of light to the outside of the surface light source device 1.
  • the reflective sheet 19 is disposed in contact with the lower surface of the light guide plate 13 and is attached to the frame 14 via an adhesive layer.
  • the reflection sheet 19 is a smooth sheet made of a high reflection film having a multilayer film structure, a white resin sheet having a high reflectance, a metal foil, or the like, and light in the light guide plate 13 does not leak from the lower surface of the surface light source device 1. Reflect light.
  • the frame 14 is a box having a frame and a bottom plate
  • the reflective sheet 19 is disposed between the light guide plate 13 and the bottom plate of the frame 14.
  • 5 to 7 are explanatory views of the process of thermocompression bonding the adhesive film 12 to the FPC 11.
  • the FPC 11 and a plurality of adhesive films 12 attached to the release paper 21 are prepared.
  • the plurality of adhesive films 12 are attached to the release paper 21 so that the adhesive films 12 are disposed between the plurality of light sources 15 mounted on the FPC 11.
  • the plurality of adhesive films 12 may be connected to each other without being limited to the example shown in FIG. 5.
  • the adhesive film 12 may be strip-shaped, and two strip-shaped adhesive films 12 may be attached to the release paper 21.
  • the adhesive film 12 is, for example, a thin tape-like member. As shown in FIG.
  • the FPC 11 and the plurality of adhesive films 12 attached to the release paper 21 are attached to the crimping device 31.
  • the crimping device 31 includes a pressing mechanism 32 and a table 33.
  • the pressure mechanism 32 incorporates a heater.
  • the table 33 may have a built-in heater.
  • the pressing mechanism 32 has a comb shape and has a plurality of protrusions 34.
  • the FPC 11 and the plurality of adhesive films 12 attached to the release paper 21 are placed on the table 33.
  • the plurality of adhesive films 12 are in contact with the lower surface of the FPC 11.
  • the protrusion 34 of the pressing mechanism 32 contacts the upper surface of the FPC 11, and the protrusion 34 of the pressing mechanism 32 presses the FPC 11.
  • the upper surface of the FPC 11 is a surface opposite to the lower surface of the FPC 11. Heat is transferred from the projection 34 of the pressing mechanism 32 to the FPC 11 to heat the adhesive film 12.
  • the adhesive film 12 is melted by heating the adhesive film 12. Since a load is applied to the FPC 11, the adhesive film 12 is crimped to the FPC 11 in a state where the adhesive film 12 is melted.
  • the heating temperature in the step shown in FIG. 7 is, for example, 50 ° C. or more and 70 ° C. or less, but is not limited to this temperature range.
  • the heating time and the pressure bonding time in the process shown in FIG. 7 are, for example, 5 seconds or more and 20 seconds or less, but are not limited to this time range.
  • the pressing mechanism 32 has a flat member and a projection 34 provided on the flat member.
  • the protrusion 34 protrudes in the direction in which the table 33 is disposed.
  • the pitch of the protrusions 34 corresponds to the pitch of the adhesive film 12.
  • the pitch of the protrusions 34 and the pitch of the adhesive film 12 match or approximate.
  • the pitch of the protrusions 34 is the sum of the distance between adjacent protrusions 34 and the width of the protrusions 34.
  • the pitch of the adhesive film 12 is the sum of the distance between the adjacent adhesive films 12 and the width of the adhesive film 12. Since the pitch of the protrusions 34 corresponds to the pitch of the adhesive film 12, when the pressure mechanism 32 contacts the upper surface of the FPC 11, heat is efficiently transmitted from the pressure mechanism 32 to the adhesive film 12.
  • the adhesive film 12 is disposed in the vicinity of the light source 15. By efficiently transferring heat from the pressure mechanism 32 to the adhesive film 12, the temperature rise of the light source 15 when the pressure mechanism 32 contacts the upper surface of the FPC 11 is suppressed. After the adhesive film 12 is melted, the adhesive film 12 is cooled to harden the adhesive film 12. The adhesive film 12 is fixed to the FPC 11 by curing the adhesive film 12. After the adhesive film 12 is cured, the release paper 21 is peeled off from the adhesive film 12.
  • FIGS. 8 and 9 are explanatory views of the process of thermocompression bonding the adhesive film 12 to the FPC 11 and the light guide plate 13.
  • the FPC 11, the adhesive film 12 and the light guide plate 13 are attached to the pressure bonding device 31.
  • the FPC 11 is installed on the light guide plate 13 such that the lower surface of the FPC 11 and the light emitting surface 13 B of the light guide plate 13 face each other, and the adhesive film 12 is brought into contact with the light guide plate 13.
  • two band-shaped adhesive films 12 one of the two band-shaped adhesive films 12 is brought into contact with the light guide plate 13.
  • a plurality of light sources 15 are mounted on the FPC 11.
  • the FPC 11 is installed at an end of the light guide plate 13 such that the light emitting surface of the light source 15 faces the light incident surface 13 A of the light guide plate 13.
  • the pressing mechanism 32 when the pressing mechanism 32 is lowered, the projection 34 of the pressing mechanism 32 contacts the upper surface of the FPC 11, and the projection 34 of the pressing mechanism 32 presses the FPC 11. Heat is transferred from the projection 34 of the pressing mechanism 32 to the FPC 11 to heat the adhesive film 12.
  • the adhesive film 12 is melted by heating the adhesive film 12. Since a load is applied to the FPC 11, the adhesive film 12 is crimped to the FPC 11 and the light guide plate 13 in a state where the adhesive film 12 is melted.
  • the heating temperature in the step shown in FIG. 9 is, for example, 50 ° C. or more and 70 ° C. or less, but is not limited to this temperature range.
  • the adhesive film 12 is melted, the adhesive film 12 is cooled to harden the adhesive film 12. The adhesive film 12 is cured, and the FPC 11 and the light guide plate 13 are bonded to each other, whereby the FPC 11 is fixed to the light guide plate 13.
  • FIGS. 10 and 11 are explanatory views of the process of thermocompression bonding the adhesive film 12 to the FPC 11, the light guide plate 13 and the frame 14.
  • the FPC 11, the adhesive film 12, the light guide plate 13 and the reflection sheet 19 are disposed in the frame 14, and the adhesive film 12 is brought into contact with the frame 14.
  • the other of the two strip adhesive films 12 is brought into contact with the frame 14.
  • the step surface is formed on the inner peripheral portion of the frame 14
  • the adhesive film 12 is brought into contact with the step surface of the frame 14. Since the FPC 11 is fixed to the light guide plate 13, when the FPC 11, the adhesive film 12 and the light guide plate 13 are disposed in the frame 14, positional deviation between the FPC 11 and the light guide plate 13 is suppressed.
  • the FPC 11, the adhesive film 12, the light guide plate 13, the frame 14 and the reflection sheet 19 are attached to the pressure bonding device 31.
  • the frame 14 accommodating the FPC 11, the adhesive film 12, the light guide plate 13 and the reflection sheet 19 is placed on the table 33.
  • the FPC 11 and the adhesive film 12 straddle the light guide plate 13 and the frame 14, and the adhesive film 12 is in contact with the light guide plate 13 and the frame 14.
  • the FPC 11 straddles the light guide plate 13 and the frame 14, and one of the two strip adhesive films 12 contacts the light guide plate 13, and the other of the two strip adhesive films 12 Contacts the frame 14.
  • the pressing mechanism 32 when the pressing mechanism 32 is lowered, the protrusions 34 of the pressing mechanism 32 contact the upper surface of the FPC 11, and the protrusions 34 of the pressing mechanism 32 press the FPC 11. Heat is transferred from the projection 34 of the pressing mechanism 32 to the FPC 11 to heat the adhesive film 12.
  • the adhesive film 12 is melted by heating the adhesive film 12. Since a load is applied to the FPC 11, the adhesive film 12 is pressure-bonded to the FPC 11, the light guide plate 13 and the frame 14 in a state where the adhesive film 12 is melted.
  • the heating temperature in the step shown in FIG. 11 is, for example, 80 ° C. or more and 120 ° C. or less, but is not limited to this temperature range.
  • the heating time and pressure bonding time in the process shown in FIG. 11 may be the same as the heating time and pressure bonding time in the process shown in FIG. 7 or may be different from the heating time and pressure bonding time in the process shown in FIG. .
  • the heating time and pressure bonding time in the process shown in FIG. 11 may be the same as the heating time and pressure bonding time in the process shown in FIG. 9 or may be different from the heating time and pressure bonding time in the process shown in FIG. .
  • the heating time and the pressure bonding time in the process shown in FIG. 11 are, for example, 10 seconds or more and 480 seconds or less, but are not limited to this time range.
  • the adhesive film 12 After the adhesive film 12 is melted, the adhesive film 12 is cooled to harden the adhesive film 12. The adhesive film 12 is cured, and the FPC 11 and the light guide plate 13 are adhered, and the FPC 11 and the frame 14 are adhered, whereby the FPC 11 is fixed to the light guide plate 13 and the FPC 11 is fixed to the frame 14 . After the adhesive film 12 is cured, the diffusion sheet 16, the prism sheet 17 and the light shielding double-sided tape 18 are sequentially placed on the light emitting surface 13B side of the light guide plate 13, whereby the surface light source device 1 is manufactured.
  • the adhesive strength of the double-sided tape 110 may be reduced by exposing the double-sided tape 110 to the atmosphere. is there.
  • the adhesive film 12 is heated to melt the adhesive film 12, and then the adhesive film 12 is pressure-bonded to the FPC 11, the light guide plate 13 and the frame 14.
  • the FPC 11 is fixed to the light guide plate 13 and the frame 14. Therefore, peeling of the adhesive film 12 from the light guide plate 13 is suppressed, and peeling of the adhesive film 12 from the frame 14 is suppressed.
  • the adhesion between the FPC 11 and the light guide plate 13 is improved, the adhesion between the FPC 11 and the frame 14 is improved, and the light leakage of the surface light source device 1 is suppressed.
  • the heating temperature in the step shown in FIG. 11 is higher than the heating temperature in the step shown in FIG. 7 and the heating temperature in the step shown in FIG. Therefore, the adhesive strength of the adhesive film 12 after the process shown in FIG. 11 is performed after the process shown in FIG. 7 is performed and before the process shown in FIG. 9 is performed. Greater than strength. Further, the adhesive strength of the adhesive film 12 after the process shown in FIG. 11 is performed is the adhesion strength of the adhesive film 12 after the process shown in FIG. 9 is performed and before the process shown in FIG. 11 is performed. Greater than strength. Therefore, the adhesive strength of the adhesive film 12 for fixing the FPC 11 to the light guide plate 13 and the frame 14 is large.
  • the pressing mechanism 32 may not have the plurality of protrusions 34, and the pressing mechanism 32 may have a flat member.
  • the flat member of pressure mechanism 32 contacts the upper surface of FPC 11, and the flat member of pressure mechanism 32 presses FPC 11.
  • the protrusion 34 of the pressure mechanism 32 contacts the upper surface of the FPC 11 and the protrusion 34 of the pressure mechanism 32 You may pressurize.
  • FIG. 12 is a comparison diagram of the shear strength when the FPC 104 is fixed to the light guide plate 101 using the double-sided tape 110 and the shear strength when the FPC 11 is fixed to the light guide plate 13 using the adhesive film 12.
  • shaft of FIG. 12 has shown shear strength (N / mm ⁇ 2 >).
  • the case where the FPC 104 is fixed to the light guide plate 101 using the double-sided adhesive tape 110 is shown as Comparative Example 1
  • the case where the FPC 11 is fixed to the light guide plate 13 using the adhesive film 12 is shown as Example 1 ing.
  • the area of the adhesive film 12 in Example 1 and the area of the double-sided tape 110 in Comparative Example 1 are substantially the same.
  • a jig is used to sandwich one end of the light guide plate 101 and the FPC 104, and the other end of the light guide plate 101, and by pulling the one end of the light guide plate 101 and the FPC 104, the shear strength is measured. Further, the jig 11 is used to sandwich one end of the FPC 11 and the light guide plate 13, and the other end of the light guide plate 13 to pull one end of the FPC 11 and the light guide plate 13 to measure the shear strength. As shown in FIG. 12, the shear strength in Example 1 is improved to about twice that in Comparative Example 1.
  • FIG. 13 shows peel strength when the FPC 104 is fixed to the light guide plate 101 and the frame 103 using the double-sided adhesive tape 110 and peel strength when the FPC 11 is fixed to the light guide plate 13 and the frame 14 using the adhesive film 12. It is a comparison figure.
  • shaft of FIG. 13 has shown peeling strength (N / mm ⁇ 2 >).
  • the case where the FPC 104 is fixed to the light guide plate 101 and the frame 103 using the double-sided adhesive tape 110 is shown as comparative example 2 and comparative example 3, and the adhesive film 12 is used to form the FPC 11 as the light guide plate 13 and the frame 14.
  • Example 2 shows the case where it fixes to.
  • the area of the adhesive film 12 in Example 2 and the area of the double-sided tape 110 in Comparative Example 2 are substantially the same.
  • the area of the double-sided tape 110 in Comparative Example 3 is about 3.3 times the area of the adhesive film 12 in Example 2.
  • the type of double-sided tape 110 in Comparative Example 2 and the type of double-sided tape 110 in Comparative Example 3 are different.
  • a jig is attached to the frame 103 on the light incident surface 101A side of the light guide plate 101, and the peel strength is measured by lifting the frame 103 in the vertical direction.
  • a jig is attached to the frame 14 on the light incident surface 13A side of the light guide plate 13, and the peel strength is measured by lifting the frame 14 in the vertical direction.
  • the peel strength in Example 2 is improved to about 38 times the peel strength in Comparative Example 2.
  • the peel strength in Example 2 is improved to about 1.25 times the peel strength in Comparative Example 3.
  • the process shown in FIG. 11 may be modified as follows.
  • the heating temperature in the step shown in FIG. 11 may be the same as the heating temperature in the step shown in FIG. 7 and the step shown in FIG.
  • the projection 34 of the pressing mechanism 32 is the FPC 11 under the condition of the heating temperature higher than the heating temperature in the process shown in FIG. 7, the process shown in FIG.
  • the projections 34 of the pressure mechanism 32 press the FPC 11.
  • the heating temperature higher than the heating temperature in the process shown in FIG. 7, the process shown in FIG. 9 and the process shown in FIG. 11 is, for example, 80 ° C. or more and 120 ° C. or less, it is not limited to this temperature range.
  • the heating time and the pressure bonding time in this case are, for example, 10 seconds or more and 480 seconds or less, but are not limited to this time range.
  • the adhesive film 12 is melted, the adhesive film 12 is cooled to harden the adhesive film 12.
  • the diffusion sheet 16, the prism sheet 17 and the light shielding double-sided tape 18 are sequentially placed on the light emitting surface 13B side of the light guide plate 13, whereby the surface light source device 1 is manufactured.
  • planar light source device 2 display panel 11
  • FPC 12 adhesive film 13
  • light guide plate 14 frame 15
  • prism sheet 18 light shielding double-sided tape 19
  • reflection sheet 21 release paper 31
  • crimping device 32 pressing mechanism 33 table 34 protrusion

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
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  • Liquid Crystal (AREA)
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Abstract

In this invention, the adhesiveness between a light-guide plate and a flexible printed circuit board is improved, and the adhesiveness between a frame and the flexible printed circuit board is improved. The planar light source device production method comprises: a step of disposing an adhesive film over a base board whereon a light source has been mounted; a first press-fitting step of heating the adhesive film and press- fitting the adhesive film to the base board while the adhesive film is in a molten state; a step of setting the base board onto a light-guide plate and bringing the adhesive film into contact with the light-guide plate; a second press-fitting step of heating the adhesive film and press- fitting the adhesive film to the base board and to the light-guide plate, while the adhesive film is in a molten state; a step of disposing the base board and the light-guide plate within a frame that has a frame for enclosing the light-guide plate, and bringing the adhesive film into contact with the frame; and a third press-fitting step of heating the adhesive film and press-fitting the adhesive film to the base board, to the light-guide plate, and to the frame, while the adhesive film is in a molten state.

Description

面光源装置の製造方法、面光源装置、表示装置及び電子機器Surface light source device manufacturing method, surface light source device, display device, and electronic apparatus
　本発明は、面光源装置の製造方法、面光源装置、表示装置及び電子機器に関する。 The present invention relates to a method of manufacturing a surface light source device, a surface light source device, a display device, and an electronic device.
　近年、電子機器の小型化、薄型化が進んでいる。このような電子機器に搭載される液晶表示装置には、同一の面積でより大きな表示領域を得るための狭額縁化や、薄型化のニーズがある。表示装置のバックライトには、例えば、白色光を出射するＬＥＤ（Light Emitting Diode）を光源とし、導光板（ライトガイドとも呼ばれる）を用いたサイドライトタイプ（エッジライト方式とも呼ばれる）の面光源装置が用いられている。配線基板をホットメルト型接着剤によって導光板に接着させた面光源装置が提案されている（特許文献１参照）。 BACKGROUND In recent years, miniaturization and thinning of electronic devices have progressed. In liquid crystal display devices mounted in such electronic devices, there is a need for narrowing of the frame for obtaining a larger display area with the same area, and thinning. Sidelight type (also referred to as edge light type) surface light source device using a light guide plate (also referred to as a light guide) with an LED (Light Emitting Diode) emitting white light as a light source for a backlight of a display device, for example Is used. There has been proposed a surface light source device in which a wiring substrate is adhered to a light guide plate by a hot melt adhesive (see Patent Document 1).
特開２００４－６０８１号公報Japanese Patent Application Laid-Open No. 2004-6081
　図１４は、面光源装置１００の断面図である。面光源装置１００は、導光板１０１と、導光板１０１の入光面１０１Ａと対向するように配置された光源１０２とを備える。導光板１０１の側面及び下面を囲うようにフレーム１０３が配置されている。フレキシブルプリント基板（以下、「ＦＰＣ」とも称する。）１０４が、導光板１０１及び光源１０２上に配置されている。導光板１０１の出光面１０１Ｂ側に拡散シート１０５、複数のプリズムシート１０６及び遮光両面シート１０７が順次載置されている。フレーム１０３の底面に反射シート１０８が配置されている。両面テープ１１０を用いて、ＦＰＣ１０４が導光板１０１及びフレーム１０３に固定されている。 FIG. 14 is a cross-sectional view of the surface light source device 100. As shown in FIG. The surface light source device 100 includes a light guide plate 101 and a light source 102 disposed to face the light incident surface 101A of the light guide plate 101. A frame 103 is disposed to surround the side surface and the lower surface of the light guide plate 101. A flexible printed circuit (hereinafter also referred to as “FPC”) 104 is disposed on the light guide plate 101 and the light source 102. A diffusion sheet 105, a plurality of prism sheets 106, and a light shielding double-sided sheet 107 are sequentially placed on the light exit surface 101B side of the light guide plate 101. A reflective sheet 108 is disposed on the bottom of the frame 103. The FPC 104 is fixed to the light guide plate 101 and the frame 103 using the double-sided adhesive tape 110.
　両面テープ１１０を導光板１０１、フレーム１０３及びＦＰＣ１０４に貼り付ける際、両面テープ１１０が大気に晒されることにより、両面テープ１１０の接着強度が低下する可能性がある。近年の狭額縁化のニーズにより、フレーム１０３の幅が小さくなっており、導光板１０１と両面テープ１１０との接着面積も小さくなっている。両面テープ１１０の接着強度は、両面テープ１１０の接着面積とトレードオフの関係にある。そのため、フレーム１０３の幅が小さくなると、両面テープ１１０の接着強度が低下し、導光板１０１と両面テープ１１０との接着面積が小さくなると、両面テープ１１０の接着強度が低下する。両面テープ１１０の接着強度が低下すると、導光板１０１から両面テープ１１０が剥離したり、フレーム１０３から両面テープ１１０が剥離したりする可能性がある。 When the double-sided adhesive tape 110 is attached to the light guide plate 101, the frame 103 and the FPC 104, the adhesive strength of the double-sided adhesive tape 110 may be reduced by exposing the double-sided adhesive tape 110 to the atmosphere. Due to the recent needs for narrowing the frame, the width of the frame 103 is reduced, and the bonding area between the light guide plate 101 and the double-sided tape 110 is also reduced. The adhesive strength of the double-sided adhesive tape 110 has a trade-off relationship with the adhesive area of the double-sided adhesive tape 110. Therefore, when the width of the frame 103 is reduced, the adhesive strength of the double-sided tape 110 is reduced, and when the adhesion area of the light guide plate 101 and the double-sided tape 110 is reduced, the adhesive strength of the double-sided tape 110 is reduced. When the adhesive strength of the double-sided adhesive tape 110 is lowered, the double-sided adhesive tape 110 may peel off from the light guide plate 101 or the double-sided adhesive tape 110 may peel off from the frame 103.
　図１５は、面光源装置１００上に液晶ディスプレイ１１１を載置した場合の模式図である。液晶ディスプレイ１１１は、ガラス１１２、上側偏光板１１３及び下側偏光板１１４を有する。図１５では、ＦＰＣ１０４が、下側偏光板１１４に固定され、面光源装置１００とガラス１１２とが液晶メインＦＰＣ１１５によって接続されている。液晶メインＦＰＣ１１５の反発性が大きいため、液晶ディスプレイ１１１側にＦＰＣ１０４が引っ張られる。そのため、導光板１０１から両面テープ１１０が剥離したり、フレーム１０３から両面テープ１１０が剥離したりすることにより、面光源装置１００からＦＰＣ１０４が飛び出し、面光源装置１００の光漏れの原因となる。 FIG. 15 is a schematic view when the liquid crystal display 111 is mounted on the surface light source device 100. As shown in FIG. The liquid crystal display 111 has a glass 112, an upper polarizing plate 113 and a lower polarizing plate 114. In FIG. 15, the FPC 104 is fixed to the lower polarizing plate 114, and the surface light source device 100 and the glass 112 are connected by the liquid crystal main FPC 115. Since the liquid crystal main FPC 115 has high resilience, the FPC 104 is pulled toward the liquid crystal display 111. Therefore, when the double-sided adhesive tape 110 peels off from the light guide plate 101 or the double-sided adhesive tape 110 peels off from the frame 103, the FPC 104 pops out of the surface light source device 100 and causes the light leakage of the surface light source device 100.
　このような状況に鑑み、本発明は、導光板とフレキシブルプリント基板との接着性を向上し、フレームとフレキシブルプリント基板との接着性を向上することを目的とする。 In view of such a situation, an object of the present invention is to improve the adhesion between the light guide plate and the flexible printed circuit and to improve the adhesion between the frame and the flexible printed circuit.
　本発明では、上記課題を解決するために、以下の手段を採用した。すなわち、本発明は、光源が実装された基板に接着膜を配置する工程と、接着膜を加熱して接着膜が溶融した状態で、接着膜を基板に圧着する第１圧着工程と、基板を導光板に設置して、接着膜と導光板とを接触させる工程と、接着膜を加熱して接着膜が溶融した状態で、接着膜を基板及び導光板に圧着する第２圧着工程と、導光板を囲む枠を有するフレーム内に基板及び導光板を配置して、接着膜とフレームとを接触させる工程と、接着膜を加熱して接着膜が溶融した状態で、接着膜を基板、導光板及びフレームに圧着する第３圧着工程と、を備える面光源装置の製造方法である。 The present invention adopts the following means in order to solve the above problems. That is, the present invention includes a step of disposing an adhesive film on a substrate on which a light source is mounted, a first pressure bonding step of pressure-bonding the adhesive film to the substrate in a state where the adhesive film is heated by heating the adhesive film, And a second pressure-bonding step of pressure-adhering the adhesive film to the substrate and the light guide plate in a step of bringing the adhesive film into contact with the light guide plate, and heating the adhesive film to melt the adhesive film. The step of arranging the substrate and the light guide plate in a frame having a frame surrounding the light plate and bringing the adhesive film and the frame into contact, and heating the adhesive film to melt the adhesive film, the adhesive film is a substrate, the light guide plate And a third pressure bonding step of pressure bonding to a frame.
　接着膜が加熱されることにより、接着膜が溶融し、接着膜の接着強度が大きくなる。接着膜が溶融した後、接着膜が冷却されることにより、接着膜が硬化する。本発明によれば、接着膜を加熱して接着膜が溶融した後、接着膜を基板、導光板及びフレームに圧着するため、接着膜の接着強度が大きい状態で、基板が導光板及びフレームに固定される。したがって、導光板から接着膜が剥離することが抑制され、フレームから接着膜が剥離することが抑制される。これにより、基板と導光板との接着性が向上し、基板とフレームとの接着性が向上する。 By heating the adhesive film, the adhesive film is melted, and the adhesive strength of the adhesive film is increased. After the adhesive film is melted, the adhesive film is cooled to harden the adhesive film. According to the present invention, the adhesive film is heated to melt the adhesive film, and then the adhesive film is pressure-bonded to the substrate, the light guide plate and the frame. It is fixed. Therefore, peeling of the adhesive film from the light guide plate is suppressed, and peeling of the adhesive film from the frame is suppressed. Thereby, the adhesion between the substrate and the light guide plate is improved, and the adhesion between the substrate and the frame is improved.
　本発明に係る面光源装置の製造方法において、第３圧着工程における加熱温度は、第１圧着工程における加熱温度及び第２圧着工程における加熱温度よりも高い。本発明に係る面光源装置の製造方法において、第３圧着工程が行われた後の接着膜の接着強度は、第１圧着工程が行われた後であって、第２圧着工程が行われる前の接着膜の接着強度よりも大きく、かつ、第２圧着工程が行われた後であって、第３圧着工程が行われる前の接着膜の接着強度よりも大きい。本発明に係る面光源装置の製造方法において、接着膜は複数であって、第１圧着工程、第２圧着工程及び第３圧着工程の少なくとも一つにおいて、複数の突起部を有する加圧機構を用いて基板が加圧され、複数の突起部のピッチが、複数の接着膜のピッチに対応している。 In the method of manufacturing the surface light source device according to the present invention, the heating temperature in the third pressure bonding step is higher than the heating temperature in the first pressure bonding step and the heating temperature in the second pressure bonding step. In the method for manufacturing a surface light source device according to the present invention, the adhesive strength of the adhesive film after the third pressure bonding step is performed is after the first pressure bonding step is performed and before the second pressure bonding step is performed. The adhesive strength of the adhesive film is larger than the adhesive strength of the adhesive film before the third pressure bonding step is performed after the second pressure bonding step is performed. In the method of manufacturing a surface light source device according to the present invention, a pressure mechanism having a plurality of adhesive films and having a plurality of protrusions in at least one of the first pressure bonding process, the second pressure bonding process, and the third pressure bonding process The substrate is pressurized by using, and the pitch of the plurality of protrusions corresponds to the pitch of the plurality of adhesive films.
　また、本発明は、光が入射する入光面を側面に有する導光板と、導光板の入光面と対向して配置された光源と、光源が実装された基板と、導光板、光源及び基板を収容するフレームと、導光板と基板との間及び基板とフレームとの間に配置され、導光板、基板及びフレームに熱圧着された接着膜と、を備える面光源装置である。本発明に係る表示装置は、本発明に係る面光源装置と、面光源装置から出射される光を受ける表示パネルとを備える。本発明に係る電子機器は、本発明に係る表示装置を備える。 Further, according to the present invention, there is provided a light guide plate having a light incident surface on which light is incident on a side surface, a light source disposed opposite to the light incident surface of the light guide plate, a substrate mounted with the light source, a light guide plate, a light source A surface light source device comprising: a frame for housing a substrate; and an adhesive film disposed between the light guide plate and the substrate and between the substrate and the frame and thermocompression-bonded to the light guide plate, the substrate and the frame. A display device according to the present invention includes the surface light source device according to the present invention, and a display panel that receives light emitted from the surface light source device. An electronic device according to the present invention includes the display device according to the present invention.
　本発明によれば、導光板とフレキシブルプリント基板との接着性を向上することができ、フレームとフレキシブルプリント基板との接着性を向上することができる。 According to the present invention, the adhesion between the light guide plate and the flexible printed circuit can be improved, and the adhesion between the frame and the flexible printed circuit can be improved.
図１Ａは、実施形態に係る面光源装置の製造方法の一例を示す図である。FIG. 1A is a view showing an example of a method of manufacturing a surface light source device according to an embodiment. 図１Ｂは、実施形態に係る接着膜の一例を示す図である。FIG. 1B is a view showing an example of the adhesive film according to the embodiment. 図２は、実施形態に係る液晶表示装置の構成を例示する斜視図である。FIG. 2 is a perspective view illustrating the configuration of the liquid crystal display device according to the embodiment. 図３は、実施形態に係る面光源装置の構成を例示する斜視図である。FIG. 3 is a perspective view illustrating the configuration of the surface light source device according to the embodiment. 図４は、実施形態に係る面光源装置の構成を例示する断面図である。FIG. 4 is a cross-sectional view illustrating the configuration of the surface light source device according to the embodiment. 図５は、接着膜をＦＰＣに圧着する工程の説明図である。FIG. 5 is an explanatory view of the step of pressure bonding the adhesive film to the FPC. 図６は、接着膜をＦＰＣに圧着する工程の説明図である。FIG. 6 is an explanatory view of the step of pressure bonding the adhesive film to the FPC. 図７は、接着膜をＦＰＣに圧着する工程の説明図である。FIG. 7 is an explanatory view of the step of pressure bonding the adhesive film to the FPC. 図８は、接着膜をＦＰＣ及び導光板に圧着する工程の説明図である。FIG. 8 is an explanatory view of a process of pressure bonding the adhesive film to the FPC and the light guide plate. 図９は、接着膜をＦＰＣ及び導光板に圧着する工程の説明図である。FIG. 9 is an explanatory view of a process of pressure bonding the adhesive film to the FPC and the light guide plate. 図１０は、接着膜をＦＰＣ、導光板及びフレームに圧着する工程の説明図である。FIG. 10 is an explanatory view of a process of pressure bonding the adhesive film to the FPC, the light guide plate and the frame. 図１１は、接着膜をＦＰＣ、導光板及びフレームに圧着する工程の説明図である。FIG. 11 is an explanatory view of a process of pressure bonding the adhesive film to the FPC, the light guide plate and the frame. 図１２は、比較例１におけるせん断強度と、実施例１におけるせん断強度との比較図である。FIG. 12 is a comparison diagram of the shear strength in Comparative Example 1 and the shear strength in Example 1. 図１３は、比較例２、３におけるピール強度と、実施例２におけるピール強度との比較図である。FIG. 13 is a comparison diagram of the peel strengths in Comparative Examples 2 and 3 and the peel strength in Example 2. 図１４は、面光源装置の断面図である。FIG. 14 is a cross-sectional view of a surface light source device. 図１５は、面光源装置上に液晶ディスプレイを載置した場合の模式図である。FIG. 15 is a schematic view when the liquid crystal display is mounted on the surface light source device.
　以下、本発明の実施の形態を、図面に基づいて説明する。なお、以下に説明する実施の形態は、本発明を実施する一例を示すものであって、本発明を以下に説明する具体的な構成に限定するものではない。 Hereinafter, embodiments of the present invention will be described based on the drawings. The embodiments described below are merely examples for practicing the present invention, and the present invention is not limited to the specific configurations described below.
　以下の実施形態では、「表示装置」は、液晶表示装置として説明され、「面光源装置」は、液晶表示装置のバックライトユニットとして説明される。なお、「面光源装置」は、表示パネルや電子ペーパによる表示装置の前面に配置されるフロントライト等、バックライトユニット以外の用途で利用されてもよい。 In the following embodiments, “display device” is described as a liquid crystal display device, and “surface light source device” is described as a backlight unit of a liquid crystal display device. The “surface light source device” may be used in applications other than a backlight unit, such as a front light disposed on the front of a display device or a display device made of electronic paper.
　〈適用例〉
　図１Ａは、実施形態に係る面光源装置の製造方法の一例を示す図である。図１Ａの点線Ａに示す工程について説明する。図１Ａの点線Ａに示す工程では、ＦＰＣ１１に接着膜１２を配置すると共に、接着膜１２を加熱して接着膜１２が溶融した状態で、接着膜１２をＦＰＣ１１に圧着する。接着膜１２を加熱して接着膜１２が溶融した状態で、接着膜１２をＦＰＣ１１に圧着する工程は、第１圧着工程の一例である。ＦＰＣ１１には、光源が実装されている。ＦＰＣ１１は、基板の一例である。図１Ａに示す例では、複数の接着膜１２が剥離紙２１に貼付された状態で、複数の接着膜１２がＦＰＣ１１に配置される。図１Ａに示す例では、複数の接着膜１２が分離しているが、図１Ａに示す例に限らず、複数の接着膜１２が互いに繋がっていてもよい。例えば、図１Ｂに示すように、接着膜１２が帯状であってもよい。図１Ｂに示す例では、２つの帯状の接着膜１２が剥離紙２１に貼付されている。図１Ｂに示す帯状の接着膜１２を用いる場合、帯状の接着膜１２が剥離紙２１に貼付された状態で、帯状の接着膜１２がＦＰＣ１１に配置される。接着膜１２が加熱されることにより、接着膜１２が溶融し、接着膜１２の接着強度が大きくなる。接着膜１２が溶融した後、接着膜１２が冷却されることにより、接着膜１２が硬化する。接着膜１２が溶融した後に接着膜１２が硬化することにより、接着膜１２の接着強度が保持される。接着膜１２の加熱温度が大きいほど、接着膜１２の接着強度が大きくなる。 <Example of application>
FIG. 1A is a view showing an example of a method of manufacturing a surface light source device according to an embodiment. The process shown by dotted line A in FIG. 1A will be described. In the process shown by dotted line A in FIG. 1A, the adhesive film 12 is disposed on the FPC 11, and the adhesive film 12 is crimped to the FPC 11 in a state where the adhesive film 12 is heated to melt the adhesive film 12. The step of pressing the adhesive film 12 to the FPC 11 in a state in which the adhesive film 12 is heated by heating the adhesive film 12 is an example of a first pressure bonding step. A light source is mounted on the FPC 11. The FPC 11 is an example of a substrate. In the example shown in FIG. 1A, the plurality of adhesive films 12 are disposed on the FPC 11 in a state where the plurality of adhesive films 12 are attached to the release paper 21. Although the plurality of adhesive films 12 are separated in the example shown in FIG. 1A, the plurality of adhesive films 12 may be connected to each other without being limited to the example shown in FIG. 1A. For example, as shown in FIG. 1B, the adhesive film 12 may be strip-shaped. In the example shown in FIG. 1B, two strip-like adhesive films 12 are attached to the release paper 21. When the strip-like adhesive film 12 shown in FIG. 1B is used, the strip-like adhesive film 12 is disposed on the FPC 11 in a state where the strip-like adhesive film 12 is attached to the release paper 21. As the adhesive film 12 is heated, the adhesive film 12 is melted and the adhesive strength of the adhesive film 12 is increased. After the adhesive film 12 is melted, the adhesive film 12 is cooled to harden the adhesive film 12. By curing the adhesive film 12 after the adhesive film 12 is melted, the adhesive strength of the adhesive film 12 is maintained. As the heating temperature of the adhesive film 12 increases, the adhesive strength of the adhesive film 12 increases.
　図１Ａの点線Ｂに示す工程について説明する。図１Ａの点線Ａに示す工程を行う前に、接着膜１２から剥離紙２１を剥離する。図１Ａの点線Ｂに示す工程では、ＦＰＣ１１を導光板１３に設置して、接着膜１２と導光板１３とを接触させる。図１Ａの点線Ｂに示す工程では、接着膜１２を加熱して接着膜１２が溶融した状態で、接着膜１２をＦＰＣ１１及び導光板１３に圧着する。接着膜１２を加熱して接着膜１２が溶融した状態で、接着膜１２をＦＰＣ１１及び導光板１３に圧着する工程は、第２圧着工程の一例である。 The process shown by dotted line B in FIG. 1A will be described. Before the process shown by the dotted line A in FIG. 1A is performed, the release paper 21 is peeled off from the adhesive film 12. In the process shown by the dotted line B in FIG. 1A, the FPC 11 is placed on the light guide plate 13 to bring the adhesive film 12 into contact with the light guide plate 13. In the process shown by the dotted line B in FIG. 1A, the adhesive film 12 is pressure-bonded to the FPC 11 and the light guide plate 13 in a state where the adhesive film 12 is heated and melted. The step of pressure bonding the adhesive film 12 to the FPC 11 and the light guide plate 13 in a state in which the adhesive film 12 is heated by heating the adhesive film 12 is an example of a second pressure bonding process.
　図１Ａの点線Ｃに示す工程について説明する。図１Ａの点線Ｃに示す工程では、ＦＰＣ１１、接着膜１２及び導光板１３をフレーム１４内に配置して、接着膜１２とフレーム１４とを接触させる。図１Ａの点線Ｃに示す工程では、接着膜１２を加熱して接着膜１２が溶融した状態で、接着膜１２をＦＰＣ１１、導光板１３及びフレーム１４に圧着する。接着膜１２を加熱して接着膜１２が溶融した状態で、接着膜１２をＦＰＣ１１、導光板１３及びフレーム１４に圧着する工程は、第３圧着工程の一例である。図１Ａの点線Ｃに示す工程における加熱温度は、図１Ａの点線Ａに示す工程における加熱温度よりも高く、図１Ａの点線Ｂに示す工程における加熱温度よりも高い。 The process shown by dotted line C in FIG. 1A will be described. In the process shown by the dotted line C in FIG. 1A, the FPC 11, the adhesive film 12 and the light guide plate 13 are disposed in the frame 14 to bring the adhesive film 12 into contact with the frame 14. In the process shown by the dotted line C in FIG. 1A, the adhesive film 12 is pressure-bonded to the FPC 11, the light guide plate 13 and the frame 14 in a state where the adhesive film 12 is heated and melted. The step of pressure-bonding the adhesive film 12 to the FPC 11, the light guide plate 13 and the frame 14 in a state in which the adhesive film 12 is heated by heating the adhesive film 12 is an example of a third pressure-bonding step. The heating temperature in the process shown by the dotted line C in FIG. 1A is higher than the heating temperature in the process shown by the dotted line A in FIG. 1A and higher than the heating temperature in the process shown by the dotted line B in FIG.
　図１Ａの点線Ｂに示す工程では、接着膜１２を加熱して接着膜１２が溶融した状態で、接着膜１２をＦＰＣ１１及び導光板１３に圧着する。ＦＰＣ１１と導光板１３とが接着され、ＦＰＣ１１が導光板１３に固定される。ＦＰＣ１１が導光板１３に固定されているため、図１Ａの点線Ｃに示す工程において、ＦＰＣ１１及び導光板１３をフレーム１４内に配置する際、ＦＰＣ１１と導光板１３との位置ずれが回避される。 In the process shown by the dotted line B in FIG. 1A, the adhesive film 12 is pressure-bonded to the FPC 11 and the light guide plate 13 in a state where the adhesive film 12 is heated and melted. The FPC 11 and the light guide plate 13 are bonded to each other, and the FPC 11 is fixed to the light guide plate 13. Since the FPC 11 is fixed to the light guide plate 13, when the FPC 11 and the light guide plate 13 are arranged in the frame 14 in the process shown by the dotted line C in FIG. 1A, positional deviation between the FPC 11 and the light guide plate 13 is avoided.
　図１Ａの点線Ｃに示す工程では、ＦＰＣ１１、接着膜１２及び導光板１３をフレーム１４内に配置した後、接着膜１２を加熱して接着膜１２が溶融した状態で、接着膜１２をＦＰＣ１１、導光板１３及びフレーム１４に圧着する。ＦＰＣ１１と導光板１３とが接着され、ＦＰＣ１１が導光板１３に固定されると共に、ＦＰＣ１１とフレーム１４とが接着され、ＦＰＣ１１がフレーム１４に固定される。接着膜１２を加熱して接着膜１２が溶融した後、接着膜１２をＦＰＣ１１、導光板１３及びフレーム１４に圧着するため、接着膜１２の接着強度が大きい状態で、ＦＰＣ１１が導光板１３及びフレーム１４に固定される。したがって、導光板１３から接着膜１２が剥離することが抑制されると共に、フレーム１４から接着膜１２が剥離することが抑制される。ＦＰＣ１１と導光板１３との接着性が向上し、ＦＰＣ１１とフレーム１４との接着性が向上することにより、面光源装置１の光漏れが抑制される。 In the process shown by the dotted line C in FIG. 1A, after disposing the FPC 11, the adhesive film 12 and the light guide plate 13 in the frame 14, the adhesive film 12 is heated in the state of heating the adhesive film 12; The light guide plate 13 and the frame 14 are crimped. The FPC 11 and the light guide plate 13 are bonded to each other, the FPC 11 is fixed to the light guide plate 13, and the FPC 11 and the frame 14 are bonded to each other, and the FPC 11 is fixed to the frame 14. After the adhesive film 12 is heated to melt the adhesive film 12, the adhesive film 12 is pressure-bonded to the FPC 11, the light guide plate 13 and the frame 14, so that the FPC 11 comprises the light guide plate 13 and the frame in a state where the adhesive strength of the adhesive film 12 is large. It is fixed to 14. Therefore, peeling of the adhesive film 12 from the light guide plate 13 is suppressed, and peeling of the adhesive film 12 from the frame 14 is suppressed. The adhesion between the FPC 11 and the light guide plate 13 is improved, and the adhesion between the FPC 11 and the frame 14 is improved, whereby light leakage of the surface light source device 1 is suppressed.
　（液晶表示装置の構成）
　図２は、実施形態に係る液晶表示装置の構成を例示する斜視図である。図２に示すように、液晶表示装置は、バックライトユニットとして配置される面光源装置１と、面光源装置１から出射される光を受ける表示パネル２とを備える。表示パネル２は、ガラス板に挟まれて封入された液晶に電圧をかけて光の透過率を増減等させることで、像を表示する。以下、面光源装置１における、表示パネル２側を上面側として、その反対面側を下面側として説明することがある。更に、このような液晶表示装置は、各種の電子機器に搭載することができる。このような液晶表示装置を備えた電子機器として、スマートフォン、デジタルカメラ、タブレット端末、電子ブック、ウェアラブル機器、カーナビゲーション装置、電子辞書、電子広告板等を例示できる。 (Configuration of liquid crystal display)
FIG. 2 is a perspective view illustrating the configuration of the liquid crystal display device according to the embodiment. As shown in FIG. 2, the liquid crystal display device includes a surface light source device 1 disposed as a backlight unit, and a display panel 2 that receives light emitted from the surface light source device 1. The display panel 2 displays an image by applying a voltage to the liquid crystal sandwiched between the glass plates to increase or decrease the light transmittance. Hereinafter, in the surface light source device 1, the display panel 2 side may be described as the upper surface side, and the opposite surface side may be described as the lower surface side. Furthermore, such a liquid crystal display device can be mounted on various electronic devices. A smartphone, a digital camera, a tablet terminal, an electronic book, a wearable device, a car navigation device, an electronic dictionary, an electronic advertisement board, etc. can be illustrated as an electronic device provided with such a liquid crystal display device.
　（面光源装置１の構成）
　図３は、実施形態に係る面光源装置１の構成を例示する斜視図である。図４は、実施形態に係る面光源装置１の構成を例示する断面図である。実施形態に係る面光源装置１は、ＦＰＣ１１、複数の接着膜１２、導光板１３、フレーム１４及び複数の光源１５を備える。また、面光源装置１は、導光板１３の上面側に順に載置される拡散シート１６、プリズムシート１７及び遮光両面テープ１８と、導光板１３の下面側に配置される反射シート１９とを備える。導光板１３の下面は、導光板１３の上面の反対側の面である。 (Configuration of surface light source device 1)
FIG. 3 is a perspective view illustrating the configuration of the surface light source device 1 according to the embodiment. FIG. 4 is a cross-sectional view illustrating the configuration of the surface light source device 1 according to the embodiment. The surface light source device 1 according to the embodiment includes an FPC 11, a plurality of adhesive films 12, a light guide plate 13, a frame 14, and a plurality of light sources 15. In addition, the surface light source device 1 includes the diffusion sheet 16, the prism sheet 17 and the light shielding double-sided tape 18 sequentially mounted on the upper surface side of the light guide plate 13, and the reflection sheet 19 disposed on the lower surface side of the light guide plate 13. . The lower surface of the light guide plate 13 is a surface opposite to the upper surface of the light guide plate 13.
　ＦＰＣ１１は、可撓性のある絶縁性フィルムである基材に、導体箔によって配線を設け、表面に保護用の絶縁性フィルムであるカバーレイ又はレジン（感光性樹脂）を接着させて構成される配線基板である。ＦＰＣ１１に配線が設けられている。ＦＰＣ１１の配線は、光源１５への電力供給等に用いられる。接着膜１２は、ＦＰＣ１１の下面等に配置され、ＦＰＣ１１を導光板１３及びフレーム１４に固定する。ＦＰＣ１１の下面は、導光板１３の上面と対向している。接着膜１２は、ＦＰＣ１１と導光板１３との間及びＦＰＣ１１とフレーム１４との間に配置されている。接着膜１２は、ＦＰＣ１１、導光板１３及びフレーム１４に熱圧着されている。 The FPC 11 is configured by providing a wiring with a conductor foil on a flexible insulating film base material and adhering a cover lay or resin (photosensitive resin), which is an insulating film for protection, on the surface. It is a wiring board. Wiring is provided on the FPC 11. The wiring of the FPC 11 is used to supply power to the light source 15 or the like. The adhesive film 12 is disposed on the lower surface or the like of the FPC 11 and fixes the FPC 11 to the light guide plate 13 and the frame 14. The lower surface of the FPC 11 faces the upper surface of the light guide plate 13. The adhesive film 12 is disposed between the FPC 11 and the light guide plate 13 and between the FPC 11 and the frame 14. The adhesive film 12 is thermocompression-bonded to the FPC 11, the light guide plate 13 and the frame 14.
　導光板１３は、概略平板状であり、ポリカーボネート樹脂やポリメチルメタクリレート樹脂等の透光性の素材で形成されている。導光板１３は、入光面１３Ａ及び出光面１３Ｂを有する。導光板１３は、側面に入光面１３Ａを有し、側面と直交する上面に出光面１３Ｂを有する。導光板１３の入光面１３Ａには、光源１５から出射される光が入射する。導光板１３の出光面１３Ｂは、光源１５から導光板１３内に入射された光を出射する。導光板１３の出光面１３Ｂは、表示パネル２と向かい合う面である。導光板１３は、光源１５から導光板１３内に入射された光を出光面１３Ｂに導き、出光面１３Ｂの全体又は一部分が光る。導光板１３は、導光板本体と、導光板本体の高さよりも高い光導入部とを備えてもよい。光源１５から出射された光が、光導入部から導光板本体内に効率よく入射し、導光板１３の光利用効率が向上する。導光板本体が光導入部よりも薄いことで、面光源装置１の薄型化が向上し、面光源装置１を備える液晶表示装置の薄型化が向上する。ただし、実施形態に係る導光板１３は、光導入部を有しない平板形状であってもよい。 The light guide plate 13 is substantially flat and made of a translucent material such as polycarbonate resin and polymethyl methacrylate resin. The light guide plate 13 has a light entrance surface 13A and a light exit surface 13B. The light guide plate 13 has a light incident surface 13A on the side surface and a light exit surface 13B on the upper surface orthogonal to the side surface. The light emitted from the light source 15 is incident on the light incident surface 13A of the light guide plate 13. The light exit surface 13 B of the light guide plate 13 emits the light incident from the light source 15 into the light guide plate 13. The light exit surface 13 B of the light guide plate 13 is a surface facing the display panel 2. The light guide plate 13 guides the light incident from the light source 15 into the light guide plate 13 to the light exit surface 13B, and the whole or a part of the light exit surface 13B is illuminated. The light guide plate 13 may include a light guide plate main body and a light introducing portion which is higher than the height of the light guide plate main body. The light emitted from the light source 15 efficiently enters the light guide plate main body from the light introducing portion, and the light use efficiency of the light guide plate 13 is improved. Since the light guide plate main body is thinner than the light introducing portion, the reduction in thickness of the surface light source device 1 is improved, and the reduction in thickness of the liquid crystal display device including the surface light source device 1 is improved. However, the light guide plate 13 according to the embodiment may have a flat plate shape without the light introducing portion.
　フレーム１４は、ＦＰＣ１１、接着膜１２、導光板１３、光源１５、拡散シート１６、プリズムシート１７及び反射シート１９を収容する。フレーム１４は、導光板１３を囲む枠を有する枠体（枠状部材）であってもよいし、導光板１３を囲む枠と、枠が立設された底板とを有する箱体（箱状部材）であってもよい。枠体は、４辺の側壁部材、開口を有する円形の側壁部材又は開口を有する楕円形の側壁部材によって形成されていてもよい。また、枠体の４辺の側壁部材のコーナー部分が直角形状であってもよいし、枠体の４辺の側壁部材のコーナー部分がＲ形状であってもよい。 The frame 14 accommodates the FPC 11, the adhesive film 12, the light guide plate 13, the light source 15, the diffusion sheet 16, the prism sheet 17, and the reflection sheet 19. The frame 14 may be a frame (frame-like member) having a frame surrounding the light guide plate 13 or a box (box-like member having a frame surrounding the light guide plate 13 and a bottom plate on which the frame is provided) ) May be. The frame may be formed by four side wall members, a circular side wall member having an opening, or an elliptical side wall member having an opening. Further, the corner portions of the side wall members on the four sides of the frame may have a right-angled shape, and the corner portions of the side wall members on the four sides of the frame may have an R shape.
　光源１５は、導光板１３の入光面１３Ａと対向して配置されている。光源１５は、白色光を蛍光部から出射する。光源１５は、例えば、ＬＥＤパッケージであるが、ＬＥＤパッケージ以外の光源が用いられてもよい。光源１５は、ＦＰＣ１１に設けられており、ＦＰＣ１１からの給電を受けて駆動し、点灯する。例えば、光源１５の発光面が、導光板１３の入光面１３Ａと対向するようにして、光源１５がＦＰＣ１１に実装されている。光源１５は、発光素子であるＬＥＤチップが蛍光体を含む透光性樹脂（樹脂層）で封止されて形成されている。若しくは、ＬＥＤチップ上に蛍光体を配置せずに、導光板１３の出光面１３Ｂ上に蛍光体層を配置してもよいし、反射シート１９上に蛍光体層を配置してもよい。なお、光源１５として、白色以外のＬＥＤ光源が用いられてもよい。ＦＰＣ１１に複数の光源１５が一定の間隔で一列に実装されてもよい。 The light source 15 is disposed to face the light incident surface 13 A of the light guide plate 13. The light source 15 emits white light from the fluorescent unit. The light source 15 is, for example, an LED package, but a light source other than the LED package may be used. The light source 15 is provided on the FPC 11 and receives power supply from the FPC 11 to drive and light it. For example, the light source 15 is mounted on the FPC 11 so that the light emitting surface of the light source 15 faces the light incident surface 13A of the light guide plate 13. The light source 15 is formed by sealing an LED chip, which is a light emitting element, with a translucent resin (resin layer) containing a phosphor. Alternatively, a phosphor layer may be disposed on the light emitting surface 13 B of the light guide plate 13 without disposing a phosphor on the LED chip, or a phosphor layer may be disposed on the reflective sheet 19. In addition, as the light source 15, LED light sources other than white may be used. A plurality of light sources 15 may be mounted on the FPC 11 in a row at regular intervals.
　導光板１３の出光面１３Ｂ上に拡散シート１６が配置され、拡散シート１６上に１枚又は２枚のプリズムシート１７が配置される。拡散シート１６は、半透明な樹脂フィルムであり、導光板１３の出光面１３Ｂから出射された光を拡散させて光の指向特性を広げる。プリズムシート１７は、上面に三角プリズム状の微細なパターンが形成された透明な樹脂フィルムであり、拡散シート１６によって拡散された光を集光し、面光源装置１を上面側から見た場合の輝度を上昇させる。遮光両面テープ１８は、上下両面が粘着面となった黒色の粘着テープである。遮光両面テープ１８は、開口を有する額縁形状（リング形状）である。遮光両面テープ１８は、フレーム１４の外周部分に沿って配置され、面光源装置１の外部に光が漏れ出ることを抑制する。 A diffusion sheet 16 is disposed on the light exit surface 13 </ b> B of the light guide plate 13, and one or two prism sheets 17 are disposed on the diffusion sheet 16. The diffusion sheet 16 is a semitransparent resin film, and diffuses the light emitted from the light exit surface 13B of the light guide plate 13 to widen the directivity characteristic of the light. The prism sheet 17 is a transparent resin film on the upper surface of which a fine pattern in the form of a triangular prism is formed, and condenses the light diffused by the diffusion sheet 16 when the surface light source device 1 is viewed from the upper surface Increase the brightness. The light shielding double-sided tape 18 is a black adhesive tape whose upper and lower surfaces are adhesive surfaces. The light shielding double-sided tape 18 has a frame shape (ring shape) having an opening. The light shielding double-sided tape 18 is disposed along the outer peripheral portion of the frame 14 to suppress the leakage of light to the outside of the surface light source device 1.
　反射シート１９は、導光板１３の下面と接するようにして配置され、接着層を介してフレーム１４に貼り付けられている。反射シート１９は、多層膜構造を有する高反射フィルム又は反射率の高い白色樹脂シートや金属箔等からなる平滑なシートであり、導光板１３内の光が面光源装置１の下面から漏れないように光を反射する。フレーム１４が、枠体及び底板を有する箱体である場合、反射シート１９は、導光板１３とフレーム１４の底板との間に配置される。 The reflective sheet 19 is disposed in contact with the lower surface of the light guide plate 13 and is attached to the frame 14 via an adhesive layer. The reflection sheet 19 is a smooth sheet made of a high reflection film having a multilayer film structure, a white resin sheet having a high reflectance, a metal foil, or the like, and light in the light guide plate 13 does not leak from the lower surface of the surface light source device 1. Reflect light. When the frame 14 is a box having a frame and a bottom plate, the reflective sheet 19 is disposed between the light guide plate 13 and the bottom plate of the frame 14.
　図５～図７は、接着膜１２をＦＰＣ１１に熱圧着する工程の説明図である。図５に示すように、ＦＰＣ１１と、剥離紙２１に貼付された複数の接着膜１２とを用意する。ＦＰＣ１１に実装された複数の光源１５の間に各接着膜１２が配置されるように、複数の接着膜１２が剥離紙２１に貼付されている。図５に示す例では、複数の接着膜１２が分離しているが、図５に示す例に限らず、複数の接着膜１２が互いに繋がっていてもよい。例えば、接着膜１２が帯状であってもよく、２つの帯状の接着膜１２が剥離紙２１に貼付されていてもよい。接着膜１２は、例えば、薄いテープ状部材である。図６に示すように、ＦＰＣ１１と、剥離紙２１に貼付された複数の接着膜１２とを、圧着装置３１に装着する。圧着装置３１は、加圧機構３２とテーブル（台）３３とを備える。加圧機構３２にはヒーターが内蔵されている。テーブル３３にヒーターを内蔵してもよい。加圧機構３２は、櫛歯形状であり、複数の突起部３４を有する。ＦＰＣ１１と、剥離紙２１に貼付された複数の接着膜１２とがテーブル３３に載置される。ＦＰＣ１１の下面に複数の接着膜１２が接触している。 5 to 7 are explanatory views of the process of thermocompression bonding the adhesive film 12 to the FPC 11. As shown in FIG. 5, the FPC 11 and a plurality of adhesive films 12 attached to the release paper 21 are prepared. The plurality of adhesive films 12 are attached to the release paper 21 so that the adhesive films 12 are disposed between the plurality of light sources 15 mounted on the FPC 11. Although the plurality of adhesive films 12 are separated in the example shown in FIG. 5, the plurality of adhesive films 12 may be connected to each other without being limited to the example shown in FIG. 5. For example, the adhesive film 12 may be strip-shaped, and two strip-shaped adhesive films 12 may be attached to the release paper 21. The adhesive film 12 is, for example, a thin tape-like member. As shown in FIG. 6, the FPC 11 and the plurality of adhesive films 12 attached to the release paper 21 are attached to the crimping device 31. The crimping device 31 includes a pressing mechanism 32 and a table 33. The pressure mechanism 32 incorporates a heater. The table 33 may have a built-in heater. The pressing mechanism 32 has a comb shape and has a plurality of protrusions 34. The FPC 11 and the plurality of adhesive films 12 attached to the release paper 21 are placed on the table 33. The plurality of adhesive films 12 are in contact with the lower surface of the FPC 11.
　図７に示すように、加圧機構３２が下降することにより、加圧機構３２の突起部３４がＦＰＣ１１の上面に接触し、加圧機構３２の突起部３４がＦＰＣ１１を加圧する。ＦＰＣ１１の上面は、ＦＰＣ１１の下面の反対側の面である。加圧機構３２の突起部３４からＦＰＣ１１に熱が伝わり、接着膜１２が加熱される。接着膜１２が加熱されることにより接着膜１２が溶融する。ＦＰＣ１１に荷重が加わるため、接着膜１２が溶融した状態で、接着膜１２がＦＰＣ１１に圧着される。図７に示す工程における加熱温度は、例えば、５０℃以上７０℃以下であるが、この温度範囲に限定されない。図７に示す工程における加熱時間及び圧着時間は、例えば、５秒以上２０秒以下であるが、この時間範囲に限定されない。 As shown in FIG. 7, when the pressing mechanism 32 is lowered, the protrusion 34 of the pressing mechanism 32 contacts the upper surface of the FPC 11, and the protrusion 34 of the pressing mechanism 32 presses the FPC 11. The upper surface of the FPC 11 is a surface opposite to the lower surface of the FPC 11. Heat is transferred from the projection 34 of the pressing mechanism 32 to the FPC 11 to heat the adhesive film 12. The adhesive film 12 is melted by heating the adhesive film 12. Since a load is applied to the FPC 11, the adhesive film 12 is crimped to the FPC 11 in a state where the adhesive film 12 is melted. The heating temperature in the step shown in FIG. 7 is, for example, 50 ° C. or more and 70 ° C. or less, but is not limited to this temperature range. The heating time and the pressure bonding time in the process shown in FIG. 7 are, for example, 5 seconds or more and 20 seconds or less, but are not limited to this time range.
　加圧機構３２は、平面部材と、平面部材に設けられた突起部３４とを有する。突起部３４は、テーブル３３が配置されている方向に向かって突起している。突起部３４のピッチは、接着膜１２のピッチに対応している。例えば、突起部３４のピッチと、接着膜１２のピッチとが一致又は近似している。突起部３４のピッチは、隣接する突起部３４の間の距離と突起部３４の幅との合計である。接着膜１２のピッチは、隣接する接着膜１２の間の距離と接着膜１２の幅との合計である。突起部３４のピッチが、接着膜１２のピッチに対応することにより、加圧機構３２がＦＰＣ１１の上面に接触した際、加圧機構３２から接着膜１２に効率的に熱が伝わる。接着膜１２は、光源１５の近傍に配置されている。加圧機構３２から接着膜１２に効率的に熱が伝わることにより、加圧機構３２がＦＰＣ１１の上面に接触した際における光源１５の温度上昇が抑制される。接着膜１２が溶融した後、接着膜１２が冷却されることにより、接着膜１２が硬化する。接着膜１２が硬化することで、接着膜１２がＦＰＣ１１に固定される。接着膜１２が硬化した後、接着膜１２から剥離紙２１を剥離する。 The pressing mechanism 32 has a flat member and a projection 34 provided on the flat member. The protrusion 34 protrudes in the direction in which the table 33 is disposed. The pitch of the protrusions 34 corresponds to the pitch of the adhesive film 12. For example, the pitch of the protrusions 34 and the pitch of the adhesive film 12 match or approximate. The pitch of the protrusions 34 is the sum of the distance between adjacent protrusions 34 and the width of the protrusions 34. The pitch of the adhesive film 12 is the sum of the distance between the adjacent adhesive films 12 and the width of the adhesive film 12. Since the pitch of the protrusions 34 corresponds to the pitch of the adhesive film 12, when the pressure mechanism 32 contacts the upper surface of the FPC 11, heat is efficiently transmitted from the pressure mechanism 32 to the adhesive film 12. The adhesive film 12 is disposed in the vicinity of the light source 15. By efficiently transferring heat from the pressure mechanism 32 to the adhesive film 12, the temperature rise of the light source 15 when the pressure mechanism 32 contacts the upper surface of the FPC 11 is suppressed. After the adhesive film 12 is melted, the adhesive film 12 is cooled to harden the adhesive film 12. The adhesive film 12 is fixed to the FPC 11 by curing the adhesive film 12. After the adhesive film 12 is cured, the release paper 21 is peeled off from the adhesive film 12.
　図８及び図９は、接着膜１２をＦＰＣ１１及び導光板１３に熱圧着する工程の説明図である。図８に示すように、ＦＰＣ１１、接着膜１２及び導光板１３を圧着装置３１に装着する。ＦＰＣ１１の下面と、導光板１３の出光面１３Ｂとが向かい合うようにして、ＦＰＣ１１を導光板１３に設置して、接着膜１２と導光板１３とを接触させる。２つの帯状の接着膜１２を用いる場合、２つの帯状の接着膜１２の一方と導光板１３とを接触させる。図８では図示していないが、ＦＰＣ１１には複数の光源１５が実装されている。光源１５の発光面が、導光板１３の入光面１３Ａと対向するように、ＦＰＣ１１が、導光板１３の端部に設置される。 FIGS. 8 and 9 are explanatory views of the process of thermocompression bonding the adhesive film 12 to the FPC 11 and the light guide plate 13. As shown in FIG. 8, the FPC 11, the adhesive film 12 and the light guide plate 13 are attached to the pressure bonding device 31. The FPC 11 is installed on the light guide plate 13 such that the lower surface of the FPC 11 and the light emitting surface 13 B of the light guide plate 13 face each other, and the adhesive film 12 is brought into contact with the light guide plate 13. When using two band-shaped adhesive films 12, one of the two band-shaped adhesive films 12 is brought into contact with the light guide plate 13. Although not shown in FIG. 8, a plurality of light sources 15 are mounted on the FPC 11. The FPC 11 is installed at an end of the light guide plate 13 such that the light emitting surface of the light source 15 faces the light incident surface 13 A of the light guide plate 13.
　図９に示すように、加圧機構３２が下降することにより、加圧機構３２の突起部３４がＦＰＣ１１の上面に接触し、加圧機構３２の突起部３４がＦＰＣ１１を加圧する。加圧機構３２の突起部３４からＦＰＣ１１に熱が伝わり、接着膜１２が加熱される。接着膜１２が加熱されることにより接着膜１２が溶融する。ＦＰＣ１１に荷重が加わるため、接着膜１２が溶融した状態で、接着膜１２がＦＰＣ１１及び導光板１３に圧着される。図９に示す工程における加熱温度は、例えば、５０℃以上７０℃以下であるが、この温度範囲に限定されない。図９に示す工程における加熱時間及び圧着時間は、例えば、５秒以上２０秒以下であるが、この時間範囲に限定されない。接着膜１２が溶融した後、接着膜１２が冷却されることにより、接着膜１２が硬化する。接着膜１２が硬化し、ＦＰＣ１１と導光板１３とが接着されることで、ＦＰＣ１１が導光板１３に固定される。 As shown in FIG. 9, when the pressing mechanism 32 is lowered, the projection 34 of the pressing mechanism 32 contacts the upper surface of the FPC 11, and the projection 34 of the pressing mechanism 32 presses the FPC 11. Heat is transferred from the projection 34 of the pressing mechanism 32 to the FPC 11 to heat the adhesive film 12. The adhesive film 12 is melted by heating the adhesive film 12. Since a load is applied to the FPC 11, the adhesive film 12 is crimped to the FPC 11 and the light guide plate 13 in a state where the adhesive film 12 is melted. The heating temperature in the step shown in FIG. 9 is, for example, 50 ° C. or more and 70 ° C. or less, but is not limited to this temperature range. The heating time and the pressure bonding time in the process shown in FIG. 9 are, for example, 5 seconds or more and 20 seconds or less, but are not limited to this time range. After the adhesive film 12 is melted, the adhesive film 12 is cooled to harden the adhesive film 12. The adhesive film 12 is cured, and the FPC 11 and the light guide plate 13 are bonded to each other, whereby the FPC 11 is fixed to the light guide plate 13.
　図１０及び図１１は、接着膜１２をＦＰＣ１１、導光板１３及びフレーム１４に熱圧着する工程の説明図である。まず、ＦＰＣ１１、接着膜１２、導光板１３及び反射シート１９をフレーム１４内に配置し、接着膜１２をフレーム１４に接触させる。２つの帯状の接着膜１２を用いる場合、２つの帯状の接着膜１２の他方をフレーム１４に接触させる。例えば、フレーム１４の内周部分に段差面が形成されている場合、接着膜１２をフレーム１４の段差面に接触させる。ＦＰＣ１１が導光板１３に固定されているため、ＦＰＣ１１、接着膜１２及び導光板１３をフレーム１４内に配置する際、ＦＰＣ１１と導光板１３との位置ずれが抑制される。次に、図１０に示すように、ＦＰＣ１１、接着膜１２、導光板１３、フレーム１４及び反射シート１９を圧着装置３１に装着する。これにより、ＦＰＣ１１、接着膜１２、導光板１３及び反射シート１９を収容するフレーム１４がテーブル３３に載置される。図１０に示す例では、ＦＰＣ１１及び接着膜１２が、導光板１３及びフレーム１４を跨ぐと共に、接着膜１２が導光板１３及びフレーム１４に接触している。２つの帯状の接着膜１２を用いる場合、ＦＰＣ１１が、導光板１３及びフレーム１４を跨ぐと共に、２つの帯状の接着膜１２の一方が導光板１３に接触し、２つの帯状の接着膜１２の他方がフレーム１４に接触する。 FIGS. 10 and 11 are explanatory views of the process of thermocompression bonding the adhesive film 12 to the FPC 11, the light guide plate 13 and the frame 14. First, the FPC 11, the adhesive film 12, the light guide plate 13 and the reflection sheet 19 are disposed in the frame 14, and the adhesive film 12 is brought into contact with the frame 14. When using two strip adhesive films 12, the other of the two strip adhesive films 12 is brought into contact with the frame 14. For example, when the step surface is formed on the inner peripheral portion of the frame 14, the adhesive film 12 is brought into contact with the step surface of the frame 14. Since the FPC 11 is fixed to the light guide plate 13, when the FPC 11, the adhesive film 12 and the light guide plate 13 are disposed in the frame 14, positional deviation between the FPC 11 and the light guide plate 13 is suppressed. Next, as shown in FIG. 10, the FPC 11, the adhesive film 12, the light guide plate 13, the frame 14 and the reflection sheet 19 are attached to the pressure bonding device 31. Thereby, the frame 14 accommodating the FPC 11, the adhesive film 12, the light guide plate 13 and the reflection sheet 19 is placed on the table 33. In the example shown in FIG. 10, the FPC 11 and the adhesive film 12 straddle the light guide plate 13 and the frame 14, and the adhesive film 12 is in contact with the light guide plate 13 and the frame 14. When using two strip adhesive films 12, the FPC 11 straddles the light guide plate 13 and the frame 14, and one of the two strip adhesive films 12 contacts the light guide plate 13, and the other of the two strip adhesive films 12 Contacts the frame 14.
　図１１に示すように、加圧機構３２が下降することにより、加圧機構３２の突起部３４がＦＰＣ１１の上面に接触し、加圧機構３２の突起部３４がＦＰＣ１１を加圧する。加圧機構３２の突起部３４からＦＰＣ１１に熱が伝わり、接着膜１２が加熱される。接着膜１２が加熱されることにより接着膜１２が溶融する。ＦＰＣ１１に荷重が加わるため、接着膜１２が溶融した状態で、接着膜１２がＦＰＣ１１、導光板１３及びフレーム１４に圧着される。図１１に示す工程における加熱温度は、例えば、８０℃以上１２０℃以下であるが、この温度範囲に限定されない。図１１に示す工程における加熱時間及び圧着時間は、図７に示す工程における加熱時間及び圧着時間と同じであってもよいし、図７に示す工程における加熱時間及び圧着時間と異なっていてもよい。図１１に示す工程における加熱時間及び圧着時間は、図９に示す工程における加熱時間及び圧着時間と同じであってもよいし、図９に示す工程における加熱時間及び圧着時間と異なっていてもよい。図１１に示す工程における加熱時間及び圧着時間は、例えば、１０秒以上４８０秒以下であるが、この時間範囲に限定されない。 As shown in FIG. 11, when the pressing mechanism 32 is lowered, the protrusions 34 of the pressing mechanism 32 contact the upper surface of the FPC 11, and the protrusions 34 of the pressing mechanism 32 press the FPC 11. Heat is transferred from the projection 34 of the pressing mechanism 32 to the FPC 11 to heat the adhesive film 12. The adhesive film 12 is melted by heating the adhesive film 12. Since a load is applied to the FPC 11, the adhesive film 12 is pressure-bonded to the FPC 11, the light guide plate 13 and the frame 14 in a state where the adhesive film 12 is melted. The heating temperature in the step shown in FIG. 11 is, for example, 80 ° C. or more and 120 ° C. or less, but is not limited to this temperature range. The heating time and pressure bonding time in the process shown in FIG. 11 may be the same as the heating time and pressure bonding time in the process shown in FIG. 7 or may be different from the heating time and pressure bonding time in the process shown in FIG. . The heating time and pressure bonding time in the process shown in FIG. 11 may be the same as the heating time and pressure bonding time in the process shown in FIG. 9 or may be different from the heating time and pressure bonding time in the process shown in FIG. . The heating time and the pressure bonding time in the process shown in FIG. 11 are, for example, 10 seconds or more and 480 seconds or less, but are not limited to this time range.
　接着膜１２が溶融した後、接着膜１２が冷却されることにより、接着膜１２が硬化する。接着膜１２が硬化し、ＦＰＣ１１と導光板１３とが接着されると共に、ＦＰＣ１１とフレーム１４とが接着されることで、ＦＰＣ１１が導光板１３に固定されると共に、ＦＰＣ１１がフレーム１４に固定される。接着膜１２が硬化した後、導光板１３の出光面１３Ｂ側に拡散シート１６、プリズムシート１７及び遮光両面テープ１８が順に載置されることにより、面光源装置１が製造される。 After the adhesive film 12 is melted, the adhesive film 12 is cooled to harden the adhesive film 12. The adhesive film 12 is cured, and the FPC 11 and the light guide plate 13 are adhered, and the FPC 11 and the frame 14 are adhered, whereby the FPC 11 is fixed to the light guide plate 13 and the FPC 11 is fixed to the frame 14 . After the adhesive film 12 is cured, the diffusion sheet 16, the prism sheet 17 and the light shielding double-sided tape 18 are sequentially placed on the light emitting surface 13B side of the light guide plate 13, whereby the surface light source device 1 is manufactured.
　図１４に示すように、両面テープ１１０を用いて、ＦＰＣ１０４を導光板１０１及びフレーム１０３に固定する場合、両面テープ１１０が大気に晒されることにより、両面テープ１１０の接着強度が低下する可能性がある。図１１に示す工程では、接着膜１２を加熱して接着膜１２が溶融した後、接着膜１２をＦＰＣ１１、導光板１３及びフレーム１４に圧着するため、接着膜１２の接着強度が大きい状態で、ＦＰＣ１１が導光板１３及びフレーム１４に固定される。したがって、導光板１３から接着膜１２が剥離することが抑制されると共に、フレーム１４から接着膜１２が剥離することが抑制される。これにより、ＦＰＣ１１と導光板１３との接着性が向上すると共に、ＦＰＣ１１とフレーム１４との接着性が向上し、面光源装置１の光漏れが抑制される。 As shown in FIG. 14, when the FPC 104 is fixed to the light guide plate 101 and the frame 103 using the double-sided tape 110, the adhesive strength of the double-sided tape 110 may be reduced by exposing the double-sided tape 110 to the atmosphere. is there. In the process shown in FIG. 11, the adhesive film 12 is heated to melt the adhesive film 12, and then the adhesive film 12 is pressure-bonded to the FPC 11, the light guide plate 13 and the frame 14. The FPC 11 is fixed to the light guide plate 13 and the frame 14. Therefore, peeling of the adhesive film 12 from the light guide plate 13 is suppressed, and peeling of the adhesive film 12 from the frame 14 is suppressed. Thus, the adhesion between the FPC 11 and the light guide plate 13 is improved, the adhesion between the FPC 11 and the frame 14 is improved, and the light leakage of the surface light source device 1 is suppressed.
　図１１に示す工程における加熱温度は、図７に示す工程における加熱温度及び図９に示す工程における加熱温度よりも高い。そのため、図１１に示す工程が行われた後の接着膜１２の接着強度は、図７に示す工程が行われた後であって、図９に示す工程が行われる前の接着膜１２の接着強度よりも大きい。また、図１１に示す工程が行われた後の接着膜１２の接着強度は、図９に示す工程が行われた後であって、図１１に示す工程が行われる前の接着膜１２の接着強度よりも大きい。したがって、導光板１３及びフレーム１４にＦＰＣ１１を固定する接着膜１２の接着強度が大きい。そのため、導光板１３から接着膜１２が剥離することが抑制されると共に、フレーム１４から接着膜１２が剥離することが抑制される。これにより、ＦＰＣ１１と導光板１３との接着性が向上すると共に、ＦＰＣ１１とフレーム１４との接着性が向上し、面光源装置１の光漏れが抑制される。 The heating temperature in the step shown in FIG. 11 is higher than the heating temperature in the step shown in FIG. 7 and the heating temperature in the step shown in FIG. Therefore, the adhesive strength of the adhesive film 12 after the process shown in FIG. 11 is performed after the process shown in FIG. 7 is performed and before the process shown in FIG. 9 is performed. Greater than strength. Further, the adhesive strength of the adhesive film 12 after the process shown in FIG. 11 is performed is the adhesion strength of the adhesive film 12 after the process shown in FIG. 9 is performed and before the process shown in FIG. 11 is performed. Greater than strength. Therefore, the adhesive strength of the adhesive film 12 for fixing the FPC 11 to the light guide plate 13 and the frame 14 is large. Therefore, peeling of the adhesive film 12 from the light guide plate 13 is suppressed, and peeling of the adhesive film 12 from the frame 14 is suppressed. Thus, the adhesion between the FPC 11 and the light guide plate 13 is improved, the adhesion between the FPC 11 and the frame 14 is improved, and the light leakage of the surface light source device 1 is suppressed.
　上記では、加圧機構３２が複数の突起部３４を有する構成例を示したが、実施形態は、この構成例に限定されない。加圧機構３２が複数の突起部３４を有せず、加圧機構３２が平面部材を有してもよい。図７に示す工程、図９に示す工程及び図１１に示す工程の少なくとも一つにおいて、加圧機構３２の平面部材がＦＰＣ１１の上面に接触し、加圧機構３２の平面部材がＦＰＣ１１を加圧してもよい。図７に示す工程、図９に示す工程及び図１１に示す工程の少なくとも一つにおいて、加圧機構３２の突起部３４がＦＰＣ１１の上面に接触し、加圧機構３２の突起部３４がＦＰＣ１１を加圧してもよい。 In the above, although the example of composition which pressurization mechanism 32 has a plurality of projection parts 34 was shown, an embodiment is not limited to this example of composition. The pressing mechanism 32 may not have the plurality of protrusions 34, and the pressing mechanism 32 may have a flat member. In at least one of the process shown in FIG. 7, the process shown in FIG. 9 and the process shown in FIG. 11, the flat member of pressure mechanism 32 contacts the upper surface of FPC 11, and the flat member of pressure mechanism 32 presses FPC 11. May be In at least one of the process shown in FIG. 7, the process shown in FIG. 9 and the process shown in FIG. 11, the protrusion 34 of the pressure mechanism 32 contacts the upper surface of the FPC 11 and the protrusion 34 of the pressure mechanism 32 You may pressurize.
　図１２は、両面テープ１１０を用いてＦＰＣ１０４を導光板１０１に固定した場合におけるせん断強度と、接着膜１２を用いてＦＰＣ１１を導光板１３に固定した場合におけるせん断強度との比較図である。図１２の縦軸は、せん断強度（Ｎ／ｍｍ２）を示している。図１２の横軸において、両面テープ１１０を用いてＦＰＣ１０４を導光板１０１に固定した場合を比較例１と示し、接着膜１２を用いてＦＰＣ１１を導光板１３に固定した場合を実施例１と示している。実施例１における接着膜１２の面積と、比較例１における両面テープ１１０の面積は同程度である。治具を用いて、導光板１０１の一端及びＦＰＣ１０４を挟むと共に、導光板１０１の他端を挟み、導光板１０１の一端及びＦＰＣ１０４を引っ張ることにより、せん断強度を測定する。また、治具を用いて、ＦＰＣ１１及び導光板１３の一端を挟むと共に、導光板１３の他端を挟み、ＦＰＣ１１及び導光板１３の一端を引っ張ることにより、せん断強度を測定する。図１２に示すように、実施例１におけるせん断強度が、比較例１におけるせん断強度の２倍程度に向上している。 FIG. 12 is a comparison diagram of the shear strength when the FPC 104 is fixed to the light guide plate 101 using the double-sided tape 110 and the shear strength when the FPC 11 is fixed to the light guide plate 13 using the adhesive film 12. The vertical axis | shaft of FIG. 12 has shown shear strength (N / mm < 2 >). In the horizontal axis of FIG. 12, the case where the FPC 104 is fixed to the light guide plate 101 using the double-sided adhesive tape 110 is shown as Comparative Example 1, and the case where the FPC 11 is fixed to the light guide plate 13 using the adhesive film 12 is shown as Example 1 ing. The area of the adhesive film 12 in Example 1 and the area of the double-sided tape 110 in Comparative Example 1 are substantially the same. A jig is used to sandwich one end of the light guide plate 101 and the FPC 104, and the other end of the light guide plate 101, and by pulling the one end of the light guide plate 101 and the FPC 104, the shear strength is measured. Further, the jig 11 is used to sandwich one end of the FPC 11 and the light guide plate 13, and the other end of the light guide plate 13 to pull one end of the FPC 11 and the light guide plate 13 to measure the shear strength. As shown in FIG. 12, the shear strength in Example 1 is improved to about twice that in Comparative Example 1.
　図１３は、両面テープ１１０を用いてＦＰＣ１０４を導光板１０１及びフレーム１０３に固定した場合におけるピール強度と、接着膜１２を用いてＦＰＣ１１を導光板１３及びフレーム１４に固定した場合にピール強度との比較図である。図１３の縦軸は、ピール強度（Ｎ／ｍｍ２）を示している。図１３の横軸において、両面テープ１１０を用いてＦＰＣ１０４を導光板１０１及びフレーム１０３に固定した場合を比較例２、比較例３と示し、接着膜１２を用いてＦＰＣ１１を導光板１３及びフレーム１４に固定した場合を実施例２と示している。実施例２における接着膜１２の面積と、比較例２における両面テープ１１０の面積は同程度である。比較例３における両面テープ１１０の面積は、実施例２における接着膜１２の面積の約３．３倍である。比較例２における両面テープ１１０の種類と、比較例３における両面テープ１１０の種類とが異なっている。導光板１０１の入光面１０１Ａ側のフレーム１０３に治具を取り付けて、フレーム１０３を垂直方向に持ち上げることにより、ピール強度を測定する。導光板１３の入光面１３Ａ側のフレーム１４に治具を取り付けて、フレーム１４を垂直方向に持ち上げることにより、ピール強度を測定する。図１３に示すように、実施例２におけるピール強度が、比較例２におけるピール強度の３８倍程度に向上している。図１３に示すように、実施例２におけるピール強度が、比較例３におけるピール強度の１．２５倍程度に向上している。 FIG. 13 shows peel strength when the FPC 104 is fixed to the light guide plate 101 and the frame 103 using the double-sided adhesive tape 110 and peel strength when the FPC 11 is fixed to the light guide plate 13 and the frame 14 using the adhesive film 12. It is a comparison figure. The vertical axis | shaft of FIG. 13 has shown peeling strength (N / mm < 2 >). In the horizontal axis of FIG. 13, the case where the FPC 104 is fixed to the light guide plate 101 and the frame 103 using the double-sided adhesive tape 110 is shown as comparative example 2 and comparative example 3, and the adhesive film 12 is used to form the FPC 11 as the light guide plate 13 and the frame 14. The case where it fixes to is shown as Example 2. The area of the adhesive film 12 in Example 2 and the area of the double-sided tape 110 in Comparative Example 2 are substantially the same. The area of the double-sided tape 110 in Comparative Example 3 is about 3.3 times the area of the adhesive film 12 in Example 2. The type of double-sided tape 110 in Comparative Example 2 and the type of double-sided tape 110 in Comparative Example 3 are different. A jig is attached to the frame 103 on the light incident surface 101A side of the light guide plate 101, and the peel strength is measured by lifting the frame 103 in the vertical direction. A jig is attached to the frame 14 on the light incident surface 13A side of the light guide plate 13, and the peel strength is measured by lifting the frame 14 in the vertical direction. As shown in FIG. 13, the peel strength in Example 2 is improved to about 38 times the peel strength in Comparative Example 2. As shown in FIG. 13, the peel strength in Example 2 is improved to about 1.25 times the peel strength in Comparative Example 3.
　〈変形例〉
　図１１に示す工程を以下のように変形してもよい。図１１に示す工程における加熱温度が、図７に示す工程及び図９に示す工程における加熱温度と同じであってもよい。図１１に示す工程が行われた後、図７に示す工程、図９に示す工程及び図１１に示す工程における加熱温度よりも高い加熱温度の条件で、加圧機構３２の突起部３４がＦＰＣ１１の上面に接触し、加圧機構３２の突起部３４がＦＰＣ１１を加圧する。図７に示す工程、図９に示す工程及び図１１に示す工程における加熱温度よりも高い加熱温度は、例えば、８０℃以上１２０℃以下であるが、この温度範囲に限定されない。この場合の加熱時間及び圧着時間は、例えば、１０秒以上４８０秒以下であるが、この時間範囲に限定されない。接着膜１２が溶融した後、接着膜１２が冷却されることにより、接着膜１２が硬化する。接着膜１２が硬化した後、導光板１３の出光面１３Ｂ側に拡散シート１６、プリズムシート１７及び遮光両面テープ１８が順に載置されることにより、面光源装置１が製造される。 <Modification example>
The process shown in FIG. 11 may be modified as follows. The heating temperature in the step shown in FIG. 11 may be the same as the heating temperature in the step shown in FIG. 7 and the step shown in FIG. After the process shown in FIG. 11 is performed, the projection 34 of the pressing mechanism 32 is the FPC 11 under the condition of the heating temperature higher than the heating temperature in the process shown in FIG. 7, the process shown in FIG. The projections 34 of the pressure mechanism 32 press the FPC 11. Although the heating temperature higher than the heating temperature in the process shown in FIG. 7, the process shown in FIG. 9 and the process shown in FIG. 11 is, for example, 80 ° C. or more and 120 ° C. or less, it is not limited to this temperature range. The heating time and the pressure bonding time in this case are, for example, 10 seconds or more and 480 seconds or less, but are not limited to this time range. After the adhesive film 12 is melted, the adhesive film 12 is cooled to harden the adhesive film 12. After the adhesive film 12 is cured, the diffusion sheet 16, the prism sheet 17 and the light shielding double-sided tape 18 are sequentially placed on the light emitting surface 13B side of the light guide plate 13, whereby the surface light source device 1 is manufactured.
１　　面光源装置
２　　表示パネル
１１　ＦＰＣ
１２　接着膜
１３　導光板
１４　フレーム
１５　光源
１６　拡散シート
１７　プリズムシート
１８　遮光両面テープ
１９　反射シート
２１　剥離紙
３１　圧着装置
３２　加圧機構
３３　テーブル
３４　突起部 1 planar light source device 2 display panel 11 FPC
12 adhesive film 13 light guide plate 14 frame 15 light source 16 diffusion sheet 17 prism sheet 18 light shielding double-sided tape 19 reflection sheet 21 release paper 31 crimping device 32 pressing mechanism 33 table 34 protrusion

Claims (7)

  1. 　光源が実装された基板に接着膜を配置する工程と、
    　前記接着膜を加熱して前記接着膜が溶融した状態で、前記接着膜を前記基板に圧着する第１圧着工程と、
    　前記基板を導光板に設置して、前記接着膜と前記導光板とを接触させる工程と、
    　前記接着膜を加熱して前記接着膜が溶融した状態で、前記接着膜を前記基板及び前記導光板に圧着する第２圧着工程と、
    　前記導光板を囲む枠を有するフレーム内に前記基板及び前記導光板を配置して、前記接着膜と前記フレームとを接触させる工程と、
    　前記接着膜を加熱して前記接着膜が溶融した状態で、前記接着膜を前記基板、前記導光板及び前記フレームに圧着する第３圧着工程と、
    　を備える、
    　面光源装置の製造方法。     Placing an adhesive film on a substrate on which the light source is mounted;
    A first pressure bonding step of pressure bonding the adhesive film to the substrate in a state where the adhesive film is heated to melt the adhesive film;
    Placing the substrate on a light guide plate and bringing the adhesive film into contact with the light guide plate;
    A second pressure-bonding step of pressure-bonding the adhesive film to the substrate and the light guide plate in a state where the adhesive film is heated to melt the adhesive film;
    Placing the substrate and the light guide plate in a frame having a frame surrounding the light guide plate, and bringing the adhesive film into contact with the frame;
    A third pressure bonding step of pressure bonding the adhesive film to the substrate, the light guide plate, and the frame in a state where the adhesive film is heated to melt the adhesive film;
    Equipped with
    Method of manufacturing surface light source device
  2. 　前記第３圧着工程における加熱温度は、前記第１圧着工程における加熱温度及び前記第２圧着工程における加熱温度よりも高い、
    　請求項１に記載の面光源装置の製造方法。     The heating temperature in the third pressure bonding step is higher than the heating temperature in the first pressure bonding step and the heating temperature in the second pressure bonding step,
    The manufacturing method of the surface light source device of Claim 1.
  3. 　前記第３圧着工程が行われた後の前記接着膜の接着強度は、前記第１圧着工程が行われた後であって、前記第２圧着工程が行われる前の前記接着膜の接着強度よりも大きく、かつ、前記第２圧着工程が行われた後であって、前記第３圧着工程が行われる前の前記接着膜の接着強度よりも大きい、
    　請求項２に記載の面光源装置の製造方法。     The adhesive strength of the adhesive film after the third pressure bonding step is performed is based on the adhesive strength of the adhesive film after the first pressure bonding step is performed and before the second pressure bonding step is performed. And is greater than the adhesive strength of the adhesive film after the second pressure bonding step is performed and before the third pressure bonding step is performed.
    The manufacturing method of the surface light source device of Claim 2.
  4. 　前記接着膜は複数であって、
    　前記第１圧着工程、前記第２圧着工程及び前記第３圧着工程の少なくとも一つにおいて、複数の突起部を有する加圧機構を用いて前記基板が加圧され、
    　複数の前記突起部のピッチが、複数の前記接着膜のピッチに対応している、
    　請求項１から３の何れか一項に記載の面光源装置の製造方法。     The adhesive film is plural, and
    In at least one of the first pressure bonding process, the second pressure bonding process, and the third pressure bonding process, the substrate is pressurized using a pressure mechanism having a plurality of protrusions.
    The pitch of the plurality of protrusions corresponds to the pitch of the plurality of adhesive films,
    The manufacturing method of the surface light source device as described in any one of Claim 1 to 3.
  5. 　光が入射する入光面を側面に有する導光板と、
    　前記導光板の入光面と対向して配置された光源と、
    　前記光源が実装された基板と、
    　前記導光板、前記光源及び前記基板を収容するフレームと、
    　前記導光板と前記基板との間及び前記基板と前記フレームとの間に配置され、前記導光板、前記基板及び前記フレームに熱圧着された接着膜と、
    　を備える面光源装置。     A light guide plate having a light incident surface to which light is incident on the side,
    A light source disposed to face the light incident surface of the light guide plate;
    A substrate on which the light source is mounted;
    A frame that accommodates the light guide plate, the light source, and the substrate;
    An adhesive film disposed between the light guide plate and the substrate and between the substrate and the frame, and thermocompression-bonded to the light guide plate, the substrate, and the frame;
    A surface light source device comprising
  6. 　請求項５に記載の面光源装置と、
    　前記面光源装置から出射される光を受ける表示パネルと、
    　を備えることを特徴とする表示装置。     The surface light source device according to claim 5;
    A display panel for receiving light emitted from the surface light source device;
    A display device comprising:
  7. 　請求項６に記載の表示装置を備えることを特徴とする電子機器。 An electronic device comprising the display device according to claim 6.
PCT/JP2018/047573 2018-01-22 2018-12-25 Planar light source device production method, planar light source device, display device and electronic machine WO2019142618A1 (en)

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