JP2013114618A - Lighting module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lighting module which can offer sufficient brightness and illuminance, improve detection sensitivity, and achieve cost reduction.SOLUTION: A lighting module 10A comprises: a light source 2; a sheet-like light guiding body 3 in which a light from the light source 2 is introduced; and a capacitive detection sensor 30 disposed on a one surface 3a side of the light guiding body 3. The light guiding body 3 is provided with light emitting parts 4 which scatter the introduced light from the light source 2 and emit the light from an other surface 3b side. The light guiding body 3 is bonded to the detection sensor 30 at adhesion areas 3f via adhesive layers 5. At least part of an area other than the adhesion areas 3f makes an input area 7A overlapping at least part of electrodes 24 of the detection sensor 30 viewed in a plan. A distance between the light guiding body 3 and the detection sensor 30 in the input area 7A is smaller than a distance between the light guiding body 3 and the detection sensor 30 in the adhesion areas 3f.

Description

  The present invention relates to a lighting module having a lighting function.

Conventionally, in an electronic device such as a mobile phone, a module having an illumination function is used (see, for example, Patent Document 1).
FIG. 9 shows an example of a module. The module 50 includes a planar light emitting device 51, a touch pad 52 provided on the upper surface side of the planar light emitting device 51, and a lower surface side of the planar light emitting device 51. And a reflection sheet 53 provided.
The planar light emitting device 51 includes a light source 2 such as an LED and a sheet-like light guide 3. The light source 2 can cause light to enter the light guide 3 from the end face. The incident light propagates in the surface direction in the light guide 3, a part of which is emitted to the upper surface side of the light guide 3 by scattering at the light extraction unit 4, and passes through the touch pad 52 as indicated by an arrow. And visually recognized by the user.
In order to transmit light from the planar light emitting device 51, a transparent type using a transparent conductive film is used as the touch pad 52.

JP 2002-100300 A

  In the module 50 shown in FIG. 9, since the light from the light guide 3 passes through the touch pad 52 and is visually recognized by the user, the luminance and the illuminance tend to be low. Further, since the touch pad 52 is required to be transparent, it is disadvantageous in terms of cost.

As the module, the structure shown in FIG. 10 is also conceivable.
A module 60 shown in FIG. 10 includes a planar light emitting device 61 and a touch pad 62 provided on the lower surface side of the planar light emitting device 61.
The touch pad 62 includes a sensor main body 64 having a capacitance type input sensor 63 and a reflection sheet 65 provided on the upper surface side of the sensor main body 64.
The input sensor 63 has a configuration in which a wiring layer 67 is provided on the upper surface of the substrate 66.
The light guide 3 of the planar light emitting device 61 is bonded to the reflection sheet 65 by an adhesive layer 68 formed at the peripheral edge. The light guide 3 is provided at an interval in the thickness direction with respect to the reflection sheet 65. Since the light guide 3 has an air layer on the lower surface side, total reflection on the lower surface side tends to occur.
Since the module 60 has the planar light emitting device 61 on the surface side, the luminance and illuminance are improved as compared with the module 50 of FIG. Further, since the touch pad 62 is not required to be transparent, an inexpensive non-transparent type can be used, and the cost can be reduced.
However, the module 60 may have insufficient detection sensitivity of the touch pad 62.
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an illumination module that can obtain sufficient luminance and illuminance, can increase detection sensitivity, and can reduce costs. .

The present invention includes a light source, a sheet-like light guide that is guided in a surface direction by introducing light from the light source, and a capacitance type detection sensor provided on one surface side of the light guide. The light guide is formed with a light extraction portion that scatters the introduced light from the light source and emits the light from the other surface, and the light guide is a part of the one surface. The adhesive region is bonded to the detection sensor via an adhesive layer, and at least a part of the region other than the adhesive region is an input region that overlaps at least a part of the electrode of the detection sensor in a plan view. An illumination module may be provided in which an interval between the light guide and the detection sensor is smaller than an interval between the light guide and the detection sensor in the adhesion region.
In the illumination module according to the aspect of the invention, the detection sensor includes a sensor convex portion that protrudes toward the light guide, and an interval between the light guide and the sensor convex portion is determined by the guide in the input region. It is good also as a structure which is the space | interval of a light body and the said detection sensor.
In the illumination module of the present invention, the detection sensor detects a change in capacitance between the detection target body and the electrode, and faces the light guide body so as to leak light from the light guide body. It is good also as a structure provided with the sheet-like reflector which reflects, and the said sensor convex part being formed in the said reflector. In the illumination module of the present invention, the sensor body includes an input sensor having a substrate, and a convex structure formed to protrude toward the light guide on the substrate, and the sensor convex portion is The reflector may be formed by being pressed and deformed by the convex structure.
The illumination module according to the present invention may be configured such that the sensor convex portion is a thick portion formed on the reflector.
In the illumination module of the present invention, the light guide has a light guide convex portion that protrudes toward the detection sensor, and an interval between the light guide convex portion and the detection sensor is the input region. It is preferable that the distance is between the light guide and the detection sensor.

According to the present invention, since the distance between the light guide and the detection sensor in the input area is smaller than the distance between the light guide and the detection sensor in the adhesion area, the gap between the light guide and the electrode in the input area is small. A certain air layer can be made thin.
By thinning the air layer having a low relative dielectric constant, the capacitance between the object to be detected and the electrode can be increased, and the detection sensitivity of the detection sensor can be increased.
Moreover, since the planar light emitting device is on the upper surface side (front surface side), light from the light guide is not blocked by the detection sensor, and sufficient luminance and illuminance can be ensured.
Further, since the detection sensor is installed on the lower surface side (rear surface side) of the planar light emitting device, it is not necessary to use an expensive transparent touch pad, so that the cost can be reduced.

It is a figure which shows schematic structure of the illumination module of 1st Embodiment of this invention, (A) is a general view, (B) is an enlarged view. It is a figure which shows schematic structure of the illumination module of 2nd Embodiment of this invention. It is a figure which shows schematic structure of the illumination module of 3rd Embodiment of this invention. It is a figure which shows schematic structure of the illumination module of 4th Embodiment of this invention. It is a figure which shows schematic structure of the illumination module of 5th Embodiment of this invention. It is a figure which shows the decorative board of the illumination module of a previous figure, (A) is sectional drawing, (B) is a top view. It is a top view which shows typically an example of a structure of the wiring layer of an input sensor. It is a top view which shows typically the other example of a structure of the wiring layer of an input sensor. It is a figure which shows schematic structure of an example of the conventional illumination module. It is a figure which shows schematic structure of the other example of the conventional illumination module.

(First embodiment)
1A and 1B are diagrams showing a schematic configuration of an illumination module 10A according to a first embodiment of the present invention, where FIG. 1A is an overall view and FIG. 1B is an enlarged view. In the following description, “upper and lower” refers to the upper and lower in FIG. The illumination module 10 </ b> A includes the planar light emitting device 1 and a touch pad unit 30 (detection sensor) provided on the lower surface side of the planar light emitting device 1.

The planar light emitting device 1 includes a light source 2 and a sheet-like (or plate-like) light guide 3.
As the light source 2, a light emitting diode (hereinafter referred to as LED) (light emitting element) can be used. In addition, the light emitting element used as the light source 2 is not limited to the LED but may be a cold cathode tube.

The light guide 3 is preferably made of a transparent light-transmitting resin and has flexibility.
As the light transmissive resin, urethane resin, acrylic resin, polycarbonate resin, silicone resin, polystyrene resin, polyimide resin, polymethyl methacrylate (PMMA) elastomer, urethane acrylate, or the like can be used.

  On the lower surface 3a (one surface, back surface) of the light guide 3 is formed a light extraction portion 4 that scatters incident light and extracts (emits) it to the upper surface 3b (other surface, surface) side of the light guide 3 can do. The light extraction unit 4 can display a target portion (for example, the operation key unit of the touch pad 20) brightly.

The light extraction unit 4 can be a plurality of microdot-like ink layers (hereinafter simply referred to as microdots) formed by printing, for example. The minute dots can be formed by a printing method such as a screen printing method, a gravure printing method, a pad printing method, or an ink jet printing method.
As the ink constituting the fine dots, for example, white ink using titanium oxide as a pigment is suitable.
In addition, the light extraction part 4 may be a rough surface part formed by a notch, sandblasting or the like formed on the surface of the light guide. Moreover, the light extraction part can also be provided on the upper surface of the light guide.

  Light from the light source 2 is introduced into the light guide 3 from the end surface 3e of the one end 3c, and propagates toward the other end 3d while being reflected by the upper surface 3b, the lower surface 3a, and the like. A part of the light is scattered by the light extraction part 4 and extracted to the upper surface 3b side. Hereinafter, the direction from the one end 3c toward the other end 3d (right side in FIG. 1) may be referred to as a light guide direction (plane direction).

The touch pad unit 30 includes a touch pad 20 (sensor body) and a reflection sheet 26 (reflector) that faces the light guide 3 and reflects light leakage from the light guide 3.
The touch pad 20 (sensor body) includes an input sensor 21 and a resist layer 22 (covering resin layer) formed thereon.
The input sensor 21 is a sensor that detects the proximity or contact of the detection target 25 such as a human finger. Here, the input sensor 21 is a capacitance type input sensor, and has a configuration in which the wiring layer 24 is provided on the upper surface 23 b of the substrate 23.
The substrate 23 is a plate material made of a resin such as PET. The substrate 23 may be a flexible substrate made of PEN (polyethylene naphthalate), polyimide, or the like, or a rigid substrate made of glass epoxy resin or the like.

The wiring layer 24 includes, for example, a plurality of electrodes 24a. When the detection object 25 such as a human finger approaches, an electrostatic capacity is formed between the detection object 25 and the electrode 24a, and this capacitance is an opposing area between the detection object 25 and the electrode 24a. And changes depending on the separation distance. For this reason, the to-be-detected body 25 and the electrode 24a form a variable capacitor.
A change in the capacitance of the variable capacitance unit is detected by a detecting means (not shown), and an input operation by the detected body 25, its position, etc. are grasped by a control unit (not shown) based on the detected value.

The wiring layer 24 can be formed, for example, by heating a silver paste containing silver particles after screen printing on the substrate 23. The wiring layer 24 may be formed by etching a copper foil laminated on the substrate 23.
The resist layer 22 ensures electrical insulation between the wiring layers 24 and prevents oxidation. The resist layer 22 has an upper surface 23b of the substrate 23 and the wiring layer 24 on the upper surface (surface on the light guide 3 side) side of the input sensor 21. It is formed to cover. For example, a general-purpose solder resist can be used as the resist layer 22.
The resist layer 22 is formed in the central region of the upper surface 23b of the substrate 23, and has a convex structure protruding upward (from the light guide 3 side) from the substrate 23.

The input sensor 21 may employ a so-called self-capacitance method in which detection is performed based on the amount of change in capacitance for each electrode, or the charge / discharge current associated with the change in capacitance at each electrode intersection. A so-called mutual capacitance method in which detection is performed based on the amount of change may be employed.
FIG. 7 is a plan view schematically showing an example of the self-capacitance type input sensor 21. In the input sensor 21 (21A), a plurality of electrodes 24a are arranged in one direction (left and right in FIG. 7). Direction). The electrode 24a is provided on the left and right with a gap.
The input sensor 21 (21A) performs detection based on the amount of change in capacitance generated between the detection target 25 and the electrode 24a closest thereto.

FIG. 8 is a plan view schematically showing an example of the mutual capacitance type input sensor 21. The input sensor 21 (21B) extends on the substrate 23 in one direction (left-right direction in FIG. 8). A plurality of first electrodes X1 to X8 (electrodes 24a) and a plurality of second electrodes Y1 to Y8 (electrodes 24a) extending in a direction crossing the first electrodes X1 to X8 (electrodes 24a) are formed.
In this input sensor 21 (21B), detection is performed based on the amount of change in charge / discharge current accompanying the change in capacitance between the intersections of the first electrodes X1 to X8 and the second electrodes Y1 to Y8.

As shown in FIG. 1, the reflection sheet 26 is for reflecting light leaked downward from the light guide 3 by the upper surface 26 b and returning it to the light guide 3, for example, PET (polyethylene terephthalate) or the like. A sheet material made of resin. The reflective sheet 26 is desirably white from the viewpoint of reflectivity.
The reflection sheet 26 is provided on the upper surface side of the touch pad 20 and faces the lower surface 3 a of the light guide 3.

  A sensor convex portion 27 is formed on the upper surface 26b of the reflection sheet 26 by being pressed upward (toward the light guide 3 side) by the resist layer 22 (convex structure) of the touch pad 20 and bulging and deforming (protruding). Has been.

The light guide 3 and the reflection sheet 26 (specifically, the upper surface 26b) are bonded to each other by the adhesive layer 5 formed on the peripheral edge of the lower surface 3a of the light guide 3. A region of the lower surface 3a where the adhesive layer 5 is formed is referred to as an adhesion region 3f. The space | interval (space | interval C2 of FIG. 1 (B)) of the adhesion | attachment area | region 3f and the reflective sheet 26 is equal to the thickness of the adhesion layer 5, for example, is 20-50 micrometers.
For the adhesive layer 5, for example, an adhesive material such as an acrylic resin, a polyurethane resin, an epoxy resin, a urethane resin, a natural rubber adhesive material, or a synthetic rubber adhesive material can be used. As the adhesive layers 5 and 6, a so-called double-sided tape-like material in which an adhesive material layer coated with an adhesive material is formed on both surfaces of a sheet-like base material can be used.

Of the lower surface 3a of the light guide 3, the region excluding the adhesive region 3f where the adhesive layer 5 is formed is the facing region 7 facing the touch pad unit 30 (specifically, the upper surface 26b of the reflective sheet 26). 7 is provided with an interval in the thickness direction with respect to the reflection sheet 26.
At least a part of the facing region 7 overlaps the electrode 24a of the touch pad 20 in plan view. In FIG. 1, the central area 7 </ b> A of the facing area 7 is an area facing the sensor convex portion 27, and is an area (input area) that overlaps at least a part of the electrode 24 a of the touchpad 20 in plan view.
The input area may be the entire area other than the adhesion area 3f or a part of the area other than the adhesion area 3f.

  As shown in FIG. 1B, the distance C1 between the lower surface 3a (the central region 7A) of the light guide 3 and the sensor convex portion 27 is equal to the light guide 3 (adhesion region) in the region where the adhesive layer 5 is formed. 3f) and the distance C2 between the reflection sheet 26 and the distance C2. The interval C1 can be set to, for example, 5 to 20 μm (for example, 5 μm or more and less than 20 μm). The interval C1 is an interval between the lower surface 3a and the sensor convex portion 27 at a position overlapping the electrode 24a in plan view, for example.

  The reflective sheet 26 and the touch pad 20 (specifically, the peripheral portion of the upper surface 23b of the substrate 23) are bonded to each other by the adhesive layer 6 formed on the peripheral portion of the lower surface 26a of the reflective sheet 26. The adhesive layer 6 can employ the same configuration as the adhesive layer 5.

In the illumination module 10A, the distance C1 between the light guide 3 (central area 7A) and the reflection sheet 26 (sensor convex portion 27) is larger than the distance C2 between the light guide 3 (adhesion area 3f) and the reflection sheet 26. Small.
For this reason, the air layer between the light guide 3 and the electrode 24a in the central region 7A can be thinned. By reducing the thickness of the air layer having a low relative dielectric constant, the capacitance between the detection object 25 and the electrode 24a can be increased, and the detection sensitivity of the input sensor 21 of the touch pad 20 can be increased.
Further, in the illumination module 10A, since the planar light emitting device 1 is on the upper surface side (front surface side), light from the light guide 3 is not blocked by the touch pad unit 30, and sufficient luminance and illuminance can be secured. .
Further, since the touch pad unit 30 is installed on the lower surface side (rear surface side) of the planar light emitting device 1, it is not necessary to use an expensive transparent touch pad, so that the cost can be reduced.

(Second Embodiment)
FIG. 2 is a diagram showing a schematic configuration of an illumination module 10B according to the second embodiment of the present invention. In the following description, portions common to the illumination module 10A of the first embodiment may be assigned the same reference numerals and description thereof may be omitted.
The illumination module 10B is different from the illumination module 10A of FIG. 1 in that a touch pad 20A (sensor body) including two wiring layers 24A and 24B is used.

In the touch pad 20A, the first wiring layer 24A is formed on the upper surface 23b of the substrate 23, the first wiring layer 24A is covered with the first resist layer 22A, and the second wiring layer 24B is formed on the first resist layer 22A. The second wiring layer 24B has a structure covered with the second resist layer 22B (convex structure).
The substrate 23 and the wiring layers 24A and 24B constitute an input sensor 21C, the input sensor 21C and the resist layers 22A and 22B constitute a touch pad 20A, and the touch pad 20A and the reflection sheet 26 constitute a touch pad unit 30A.
The resist layer 22 </ b> A is formed over the entire upper surface 23 b of the substrate 23. The resist layer 22B is formed in the central region of the upper surface of the resist layer 22A, and has a convex structure protruding upward (from the light guide 3 side) from the resist layer 22A.
The wiring layers 24A and 24B do not need to be formed of the same conductor. For example, the wiring layer 24A may be formed of a metal such as copper, and the wiring layer 24B may be formed of a conductive paste such as silver paste or carbon paste.
The adhesive layer 6 is provided between the resist layer 22 </ b> A and the reflection sheet 26.

The sensor convex part 27 is formed by the reflective sheet 26 being pressed upward by the resist layer 22B and bulging and deforming.
The wiring layers 24A and 24B do not need to be formed of the same conductor. For example, the wiring layer 24A may be formed of a metal such as copper, and the wiring layer 24B may be formed of a conductive paste such as silver paste or carbon paste.

  In the illumination module 10 </ b> B, the distance between the light guide 3 (central area 7 </ b> A) and the sensor convex portion 27 of the reflection sheet 26 is smaller than the distance between the light guide 3 (adhesion area 3 f) and the reflection sheet 26. Therefore, like the illumination module 10A of FIG. 1, the capacitance can be increased and the detection sensitivity can be increased. In addition, the luminance and illuminance can be increased and the cost can be reduced.

(Third embodiment)
FIG. 3 is a diagram showing a schematic configuration of an illumination module 10C according to the third embodiment of the present invention.
The illumination module 10C is different from the illumination module 10A of FIG. 1 in that a reflection sheet 36 having a sensor convex portion 37 on the upper surface 36b is used.
The sensor convex portion 37 (thick portion) is formed to protrude upward (to the light guide 3 side) by thickening the central region of the reflection sheet 36. The sensor convex portion 37 is formed in a region including the electrode 24a in plan view. The lower surface 36a of the reflection sheet 36 is formed flat.

  In the illumination module 10 </ b> C, the distance between the light guide 3 (central area 7 </ b> A) and the sensor convex portion 37 is smaller than the distance between the light guide 3 (adhesion area 3 f) and the reflection sheet 36. Therefore, like the illumination module 10A of FIG. 1, the capacitance can be increased and the detection sensitivity can be increased. In addition, the luminance and illuminance can be increased and the cost can be reduced.

(Fourth embodiment)
FIG. 4 is a diagram showing a schematic configuration of an illumination module 10D according to the fourth embodiment of the present invention.
The illumination module 10D is different from the illumination module 10A of FIG. 1 in that a light guide 3A having a light guide convex portion 3g on the lower surface 3a is used.
The light guide convex portion 3g (thick portion) is formed to protrude downward (touch pad unit 30 side) by thickening the central region of the light guide 3. The light guide convex portion 3g is formed in a region including the electrode 24a in plan view. The light guide convex portion 3 g is a region (input region) facing the sensor convex portion 27. The upper surface 3b of the light guide 3 is formed flat.

  In the illumination module 10 </ b> D, the interval between the light guide convex portion 3 g (input region) of the light guide 3 and the reflection sheet 26 is smaller than the interval between the adhesion region 3 f of the light guide 3 and the reflection sheet 26. Therefore, like the illumination module 10A of FIG. 1, the capacitance can be increased and the detection sensitivity can be increased. In addition, the luminance and illuminance can be increased and the cost can be reduced.

(Fifth embodiment)
FIG. 5 is a diagram showing a schematic configuration of an illumination module 10E that is the fifth embodiment of the present invention.
This illumination module 10E is different from the illumination module 10A of FIG. 1 in that a decorative plate 40 (cover plate) is provided on the upper surface 3b side of the light guide 3.
The decorative plate 40 has a size that can cover substantially the entire light guide 3 in a plan view, and is bonded to the upper surface 3b of the light guide 3 via an adhesive layer 41 provided on the peripheral edge.
The decorative board 40 is made of a resin material such as PET. The decorative plate 40 is preferably made of a transparent material so that the light emitted from the light guide 3 can be visually recognized from the outside.
By providing the decorative plate 40, the light guide 3 can be prevented from being scratched or soiled, and the durability of the lighting module 10E can be enhanced.
The pressure-sensitive adhesive layer 6 may be formed only on a part of the lower surface of the reflective sheet 26 (for example, only at the peripheral edge) or may be formed on the entire lower surface of the reflective sheet 26.

As shown in FIGS. 6A and 6B, in the lighting module 10E, the decorative plate 40 is made of an opaque material, and the light from the light guide 3 can be visually recognized from the outside on the decorative plate 40. An opening 42 can also be formed.
If the opening 42 has a shape representing a number, a character, a symbol, a figure, a pattern, etc., light emission corresponding to the shape can be obtained. In the example shown in FIG. 6B, the opening 42 functions as a display indicating the number “1”.

DESCRIPTION OF SYMBOLS 1 ... Planar light-emitting device, 2 ... Light source, 3 ... Light guide, 3a ... Lower surface (one surface), 3b ... Upper surface (the other surface), 3f ... Adhesion Area, 3g ... light guide convex part, 4 ... light extraction part, 5 ... adhesive layer, 7A ... central area (input area) of the lower surface of the light guide, 10A to 10E -Lighting module, 20 ... touch pad, 24a ... electrode, 26, 36 ... reflective sheet (reflector), 27 ... sensor convex part, 37 ... sensor convex part (thick wall) Part), 30... Touch pad unit (detection sensor), C1... Distance between the central area and the sensor convex part of the reflective sheet (interval between the light guide and the detection sensor in the input area), C2. The distance between the adhesion region and the reflection sheet (the distance between the light guide and the detection sensor in the adhesion region).

Claims (6)

A light source;
A sheet-like light guide body in which light from the light source is introduced and guided in a plane direction;
A capacitance type detection sensor provided on one surface side of the light guide,
The light guide is formed with a light extraction portion that scatters the introduction light from the light source and emits the light from the other surface side,
The light guide is adhered to the detection sensor through an adhesive layer in an adhesion region that is a part of the one surface,
At least a part of the region other than the adhesion region is an input region that overlaps at least a part of the electrode of the detection sensor in plan view,
An illumination module, wherein an interval between the light guide and the detection sensor in the input region is smaller than an interval between the light guide and the detection sensor in the adhesion region. The detection sensor has a sensor convex portion protruding toward the light guide,
The illumination module according to claim 1, wherein an interval between the light guide and the sensor convex portion is an interval between the light guide and the detection sensor in the input region. The detection sensor includes a sensor main body that detects a change in capacitance between the detection target and the electrode, and a sheet-like reflector that faces the light guide and reflects light leakage from the light guide. And
The illumination module according to claim 2, wherein the sensor convex portion is formed on the reflector. The sensor body has an input sensor having a substrate, and a convex structure formed on the substrate so as to protrude toward the light guide,
The illumination module according to claim 3, wherein the sensor convex portion is formed by the reflector being pressed by the convex structure to bulge and deform.   The illumination module according to claim 3, wherein the sensor convex portion is a thick portion formed on the reflector. The light guide has a light guide convex portion protruding toward the detection sensor,
The illumination module according to claim 1, wherein an interval between the light guide body convex portion and the detection sensor is an interval between the light guide body and the detection sensor in the input region.

Images