JP5517815B2 - Capacitance sensor sheet - Google Patents

Description

  The present invention relates to a capacitance sensor sheet used for mobile devices such as mobile phones, game devices, automobile devices and the like.

  A key sheet for operation is installed in some portable devices, game devices, and automobile devices. The key sheet is provided with an illumination function from the viewpoint of improving operability in a dark place. (See Patent Documents 1 and 2).

  Although not shown, the key sheet having this type of function is bonded to the surface of the base sheet, a transparent base sheet that guides light from the light source, a transparent key top that is bonded to the surface of the base sheet, and the surface of the base sheet. The resin top cover, the dark print layer adhered to the back surface of the base sheet, the diffusion portion for guiding the light of the base sheet to the key top, and the presser provided on the back surface of the dark print layer ing.

  The base sheet is made of, for example, a resin film, and a transparent resin layer made of resin is interposed between the dark color print layer and the base sheet. These interfaces function to suppress the incidence of light rays on the dark print layer by being formed on a smooth surface.

Japanese Patent No. 4402735 JP 2010-123367 A

  The conventional capacitance sensor sheet is configured as described above, and since the base sheet and the transparent resin layer are both made of a simple resin, the difference in the refractive index of light cannot be increased. As a result, there is a problem that light rays enter the transparent resin layer from the base sheet and the light rays leak to impair operability and aesthetics.

  The present invention has been made in view of the above, and an object of the present invention is to provide a capacitive sensor sheet that can improve operability and aesthetics by suppressing leakage of light rays.

In the present invention, in order to solve the above problems, a sensor electrode layer having conductivity, a light guide layer that opposes the sensor electrode layer and guides light from the outside in a plane direction, and a surface of the light guide layer A light diffusing pattern that is formed in the light emitting region and radiates light rays guided to the light guide layer to the outside. When a conductor approaches the sensor electrode layer, a capacitor is formed to detect a change in capacitance. And
The sensor electrode layer is formed by etching a metal thin film, and by integrating the sensor electrode layer and the opposing back surface of the light guide layer, leakage of light from the opposing back surface of the light guide layer is suppressed. It is characterized by that.

In addition, the reflective printing layer formed in areas other than the light emission area | region of the light guide layer surface, and the light shielding printing layer laminated | stacked on this reflective printing layer can be included.
The sensor electrode layer includes a plurality of first sensor electrodes arranged in any one of the XY directions on the back surface facing the light guide layer and a plurality of sensors arranged in the other on the other side in the XY directions on the back surface facing the light guide layer. A second sensor electrode and a plurality of dummy electrodes interposed between the plurality of first and second sensor electrodes to reduce light leakage can be included.

The sensor electrode layer includes a base material laminated on the opposite back surface of the light guide layer, and a plurality of first and second sensor electrodes and a plurality of dummy electrodes can be vapor-deposited on the base material. is there.
Furthermore, it is possible to adhere a key top facing the light diffusion pattern to the surface of the light guide layer.

  Here, the metal thin film in the claims includes at least a thin film made of aluminum, chromium, iron, nickel, or an alloy thereof. When this metal thin film is an aluminum thin film, it includes vapor deposition films formed by various vapor deposition methods (for example, vacuum vapor deposition method, CVD method, etc.), and is appropriately mirror-finished to improve the light reflection characteristics. Can do. Etching includes chemical etching and dry etching (for example, laser etching and dry etching). The light emitting region and the light diffusion pattern may be singular or plural. Furthermore, light transparency can be imparted to at least a part of the key top.

  According to the present invention, when the light source emits light and irradiates the capacitive sensor sheet with a light beam, the light beam is incident on the inside from the peripheral surface of the light guide layer, and is guided in the surface direction while being reflected, and the light diffusion pattern Diffuse to the outside and illuminate. At this time, since the sensor electrode layer made of a metal thin film integrated on the back surface of the light guide layer reflects the light beam as a reflection layer, the light beam hardly leaks from the back surface of the light guide layer.

  According to the present invention, the sensor electrode layer is formed by etching a metal thin film, and the sensor electrode layer and the opposite back surface of the light guide layer are integrated, so that leakage of light rays is suppressed and operability and aesthetics are improved. There is an effect that can be.

In addition, according to the second aspect of the invention, it is possible to suppress the leakage of light from other than the light emitting region on the surface of the light guide layer, and to improve the light guide property of the light.
According to the third aspect of the present invention, when a conductor approaches the plurality of first and second sensor electrodes, a capacitor can be formed to detect a change in capacitance. In addition, the plurality of dummy electrodes can reduce leakage of light from the gap between the first and second sensor electrodes, and can reflect more light.

According to the invention of claim 4, when it is difficult to directly form the sensor electrode layer with the metal thin film on the back surface of the light guide layer, the sensor electrode layer is easily integrated with the back surface of the light guide layer. It becomes possible.
Furthermore, according to the fifth aspect of the present invention, it is possible to illuminate all of the key tops or a part of the peripheral portion and the like to alert the user during operation, so that the operability of the capacitance sensor sheet can be improved. I can expect.

It is a section explanatory view showing typically an embodiment of a capacitance sensor sheet concerning the present invention. It is a section explanatory view showing typically a 2nd embodiment of a capacitance sensor sheet concerning the present invention. It is a section explanatory view showing typically a 3rd embodiment of a capacitance sensor sheet concerning the present invention. It is a section explanatory view showing typically the 4th embodiment of the capacitance sensor sheet concerning the present invention.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. A capacitance sensor sheet according to the present embodiment includes a conductive sensor electrode layer 1 and an upper side of the sensor electrode layer 1 as shown in FIG. A light guide layer 10 that guides the light beam from the opposite side, and a light diffusion pattern 20 that is formed on the light guide layer 10 and irradiates the light beam guided to the outside. A sensor sheet that detects a change in capacitance by forming a capacitor when a finger as a conductor approaches the first and second sensor electrodes 2 and 3, and the sensor electrode layer 1 is an aluminum thin film that is a metal thin film The sensor electrode layer 1 and the light guide layer 10 are integrated with each other.

  The sensor electrode layer 1 is formed by depositing on the back surface of the light guide layer 10 an aluminum thin film excellent in the reflection characteristics and conductivity of light rays (see the arrow in FIG. 1), specifically, a thin and uniform aluminum deposited film. The aluminum thin film is formed into a predetermined pattern by dry etching, preferably laser etching, to detect the approach of the finger and reflect the light in the light guide layer 10 to prevent the leakage. It also functions as a reflective layer to suppress.

  The sensor electrode layer 1 includes a plurality of first sensor electrodes 2 arranged at predetermined intervals in the X direction on the back surface of the light guide layer 10 and a plurality of sensors arranged at predetermined intervals in the Y direction on the back surface of the light guide layer 10. A second sensor electrode 3 and a plurality of dummy electrodes 4 that are interposed in the gaps between the plurality of first and second sensor electrodes 2 and 3 to reduce light leakage are selected as a cover protective layer (not shown). The plurality of first and second sensor electrodes 2 and 3 are electrically connected to an external electronic circuit (not shown) via a connection line.

  The plurality of first sensor electrodes 2 are connected to adjacent first sensor electrodes 2 with elongated conductive lines, and each first sensor electrode 2 is formed in a substantially rhombic shape so that a finger touch operation is performed. It is targeted. The plurality of second sensor electrodes 3 are connected to adjacent second sensor electrodes 3 with elongated conductive lines, and each second sensor electrode 3 is formed in a substantially rhombic shape so that a finger touch operation can be performed. It becomes a target.

  The intersection between the conductive line of the first sensor electrode 2 and the conductive line of the second sensor electrode 3 is formed in a jumper structure from the viewpoint of preventing a short circuit. Each dummy electrode 4 is formed in the same shape as the first and second sensor electrodes 2 and 3 or is formed in a thin line shape or a small piece shape. As much as possible to prevent general interference and light leakage.

  The light guide layer 10 is formed into a flexible thin plate with flat front and back surfaces using a predetermined insulating material, and a part of the peripheral surface is opposed to an external LED with a gap, It functions to guide light incident from this LED in the surface direction. Examples of the predetermined material of the light guide layer 10 include films and sheets of silicone rubber, polycarbonate, urethane resin, and the like that are excellent in light transmittance. The surface of the light guide layer 10 is formed as a smooth surface, and the light emitting region 11 is partially partitioned. A light diffusion pattern 20 is formed in the light emitting region 11.

  In areas other than the light emitting area 11 on the surface of the light guide layer 10, a reflective printing layer 12 that reduces light leakage is laminated by screen printing or the like. A light-shielding print layer 13 is laminated by screen printing or the like, and a light-transmitting cover protective layer (not shown) that is touched by a finger is selectively laminated and adhered to the light-shielding print layer 13. . The reflective printing layer 12 is formed into a thin film using an insulating white resin material or the like. Further, the light-shielding print layer 13 is formed in a thin film with a black or dark blue resin material, ink, or the like that prevents transmission of light.

  The light diffusion pattern 20 is printed in a substantially dot shape by a material having a high refractive index or reflectance, for example, in the light emitting region 11 of the light guide layer 10, and the light beam that is totally reflected in the light guide layer 10 and guided is externally upward. Diffuse to irradiate.

  In the above configuration, when manufacturing a capacitive sensor sheet, first, an aluminum thin film is directly deposited on the back surface of the light guide layer 10 to be integrally formed, and the aluminum thin film is laser-etched to increase the height of the sensor electrode layer 1. Pattern formation with accuracy. At this time, since laser etching is performed instead of wet etching, mask patterns and chemicals can be omitted, and the manufacturing process can be simplified.

  When the sensor electrode layer 1 is patterned on the back surface of the light guide layer 10, the light diffusion pattern 20 is formed in the light emitting region 11 partitioned on the surface of the light guide layer 10, and in the region other than the light emitting region 11 of the light guide layer 10. If the reflective printing layer 12 and the light-shielding printing layer 13 are sequentially laminated, a capacitance sensor sheet can be manufactured. The manufactured capacitive sensor sheet is mounted as an input unit in a predetermined electronic device and is adjacent to an LED or the like.

  Next, in the operation of the capacitance sensor sheet, when the LED emits light and irradiates light, the light is incident from the peripheral surface of the light guide layer 10 and guided in the XY directions while being totally reflected, The light is diffused from the light diffusion pattern 20 upward and illuminated. At this time, since the first and second sensor electrodes 2 and 3 and the dummy electrode 4 of the sensor electrode layer 1 integrated on the back surface of the light guide layer 10 reflect the light as a reflection layer, the back surface of the light guide layer 10 It is possible to prevent the light beam from leaking out.

  According to the above configuration, the material of the sensor electrode layer 1 and the light guide layer 10 are different, and the difference in the refractive index of the light beam can be made larger than before, so that the light beam leaks from the light guide layer 10. The light guide property is not deteriorated, and the operability and aesthetic appearance of the capacitance sensor sheet are not impaired. Further, since the sensor electrode layer 1 also serves as a reflective layer, it is not necessary to use a separate reflective layer, and the number of parts can be reduced and the thickness can be reduced.

  In addition, since an aluminum thin film is used as the metal thin film, the bondability, conductivity, electrical characteristics, and the like can be greatly improved, and the thickness and weight can be reduced. In particular, if an aluminum vapor deposition film is used, the thickness can be reduced to 1 μm or less, so that a remarkable reduction in thickness can be expected. Furthermore, since the reflective printing layer 12 and the light-shielding printing layer 13 cover the light guide layer 10 other than the light emitting region 11, the light guide layer 10 is prevented from leaking light from the surface, and the light guide property is greatly improved. Improvement can be expected.

Next, FIG. 2 shows a second embodiment of the present invention. In this case, the sensor electrode layer 1 is provided with an insulating base material 5 laminated on the back surface of the light guide layer 10. A plurality of first and second sensor electrodes 2 and 3 and a plurality of dummy electrodes 4 are formed on the surface of the base material 5 by vapor deposition.
Although it does not specifically limit as the base material 5, For example, the film made from a thin polyethylene terephthalate (PET) etc. which is excellent in intensity | strength, dimensional stability, etc. are used.

  In the above configuration, when manufacturing a capacitance sensor sheet, first, an aluminum thin film is vapor-deposited on the surface of the prepared substrate 5 and integrally formed, and this aluminum thin film is laser etched to raise the sensor electrode layer 1. The pattern is accurately formed, and then the light guide layer 10 and the sensor electrode layer 1 are integrally formed, and the plurality of first and second sensor electrodes 2 and 3 and the dummy electrode 4 are respectively integrated on the back surface of the light guide layer 10. Turn into.

  When the sensor electrode layer 1 is integrated with the back surface of the light guide layer 10, the light diffusion pattern 20 is formed in the light emitting region 11 of the light guide layer 10, and the reflective printing layer is formed in a region other than the light emitting region 11 of the light guide layer 10. 12 and the light-shielding print layer 13 can be sequentially laminated to produce a capacitance sensor sheet. The other parts are substantially the same as those in the above embodiment, and thus description thereof is omitted.

  Also in this embodiment, the same effect as the above embodiment can be expected, and when the aluminum thin film is thin and brittle, the sensor electrode layer 1 cannot be directly deposited on the back surface of the light guide layer 10 to be integrally formed. Obviously, the sensor electrode layer 1 can be easily integrated with the back surface of the light guide layer 10. Moreover, since the base material 5 also functions as a cover protective layer, a separate cover protective layer can be omitted.

Next, FIG. 3 shows a third embodiment of the present invention. In this case, the sensor electrode layer 1 includes an insulating base material 5 laminated on the back surface of the light guide layer 10. A plurality of first sensor electrodes 2 and dummy electrodes 4 are vapor-deposited and integrated on the surface of the substrate 5, and a plurality of second sensor electrodes 3 are vapor-deposited and integrated on the back surface of the substrate 5. I have to. The other parts are substantially the same as those in the above embodiment, and thus description thereof is omitted.
In the present embodiment, it is obvious that the same operational effects as those of the above embodiment can be expected, and the configuration of the sensor electrode layer 1 can be diversified.

Next, FIG. 4 shows a fourth embodiment of the present invention. In this case, a key top 30 that opposes the light diffusion pattern 20 is formed on the surface of the light guide layer 10 with a light-transmitting adhesive layer. The capacitance sensor sheet is used as a key sheet.
The key top 30 is formed into a substantially rectangular plane using a predetermined resin (for example, polycarbonate, acrylic resin, urethane resin, silicone resin, etc.), and is provided with light transparency as necessary. The pattern (characters, figures, symbols, etc.) is printed and pressed. The other parts are substantially the same as those in the above embodiment, and thus description thereof is omitted.

  In this embodiment, the same effect as that of the above embodiment can be expected, and the entire key top 30 or a part of the peripheral edge can be illuminated to call attention. It is obvious that the operation can be facilitated. In addition, the configuration of the capacitance sensor sheet can be diversified.

  In the above embodiment, the sensor electrode layer 1 is formed by laser etching of an aluminum thin film. However, the present invention is not particularly limited to this. For example, various metal thin films other than the aluminum thin film may be formed by chemical etching or dry etching. Also, the first sensor electrode 2 is arranged in the X direction and the second sensor electrode 3 is arranged in the Y direction. However, the first sensor electrode 2 is arranged in the Y direction and the second sensor electrode is arranged in the X direction. 3 may be arranged.

  Further, the first and second sensor electrodes 2 and 3 may be appropriately formed in a planar circle, rectangle, polygon or the like. Further, the light guide layer 10 and the sensor electrode layer 1 are not integrally formed when the light guide layer 10 is formed, but the base material 5 of the sensor electrode layer 1 is laminated and adhered to the back surface of the formed light guide layer 10 later. You can also. Further, the key top 30 can be bonded with a light-transmitting adhesive.

  The capacitance sensor sheet according to the present invention can be used in the fields of home appliances, portable devices, game devices, computer devices, automobile devices, information devices, and the like.

DESCRIPTION OF SYMBOLS 1 Sensor electrode layer 2 1st sensor electrode 3 2nd sensor electrode 4 Dummy electrode 5 Base material 10 Light guide layer 11 Light emission area | region 12 Reflective printing layer 13 Light-shielding printing layer 20 Light diffusion pattern 30 Key top

Claims (5)

A sensor electrode layer having conductivity, a light guide layer that opposes the sensor electrode layer and guides light rays from the outside in a plane direction, and is formed in a light emitting region on the surface of the light guide layer and led to the light guide layer. A capacitance diffusion sensor sheet for detecting a change in capacitance by forming a capacitor when a conductor approaches the sensor electrode layer.
The sensor electrode layer is formed by etching a metal thin film, and by integrating the sensor electrode layer and the opposing back surface of the light guide layer, leakage of light from the opposing back surface of the light guide layer is suppressed. A capacitance sensor sheet characterized by the above.   The capacitance sensor sheet according to claim 1, comprising a reflective print layer formed in a region other than the light emitting region on the surface of the light guide layer, and a light shielding print layer laminated on the reflective print layer.   The sensor electrode layer includes a plurality of first sensor electrodes arranged in any one of the XY directions on the back surface facing the light guide layer, and a plurality of second sensors arranged in either one of the XY directions on the back surface facing the light guide layer. The electrostatic capacitance sensor sheet according to claim 1 or 2, comprising a plurality of sensor electrodes and a plurality of dummy electrodes interposed between the plurality of first and second sensor electrodes to reduce light leakage.   The static electricity source according to claim 3, wherein the sensor electrode layer includes a base material laminated on the opposite back surface of the light guide layer, and a plurality of first and second sensor electrodes and a plurality of dummy electrodes are formed on the base material by vapor deposition. Capacitance sensor sheet.   5. The capacitance sensor sheet according to claim 1, wherein a key top facing the light diffusion pattern is bonded to the surface of the light guide layer.

Images