Patent Publication Number: US-2013234999-A1

Title: Input pen

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
     This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2012-053114, filed Mar. 9, 2012, the entire contents of which is incorporated herein by reference. 
     BACKGROUND OF THE INVENTION  
     1. Field of the Invention 
     The present invention relates to an input pen. Specifically, the present invention relates to an input pen that is used to perform an input operation on an electronic device including a touch panel. 
     2. Description of the Related Art 
     Electronic devices including a so-called touch panel, such as smartphones (highly functional mobile phones) and tablet type information terminals, have been rapidly spreading in recent years. The touch panel is an input device including a display device such as a liquid crystal or organic Electroluminescent (EL) display device, and a touch sensor arranged on the front surface (the side to be viewed) of the display device or formed integrally with the display device. By viewing text information or an image displayed on the display device, and touching an arbitrary area on the display with a stylus pen or a finger, the user can perform a desired input operation. 
     This type of input device (including the touch panel type and the pen input type), on which an input operation is performed by the user touching it with a stylus pen or a finger (human body), has been used in various products for years. For example, it is used in pen tablets that are used as peripheral devices for desktop and laptop personal computers, portable gaming devices, car navigation systems, mobile information terminals (Personal Digital Assistants [PDAs]), cash machines (Automated Teller Machines [ATMs]) for banking institutions, and ticket vending machines. That is, this type of input device is used in a wide range of product areas. 
     Regarding touch panels, there are various types of known touch panels (touch sensors). For example, in smartphones and tablet type information terminals which have been rapidly spreading in recent years, the capacitance type touch panel is mainly used. In the capacitance type touch panel, a change in electrostatic capacitance is detected that occurs between a fingertip (or a conductive material equivalent to a finger) and a conductive film on the touch-panel side by the touch panel being touched by the fingertip (or a conductive material equivalent to a finger), whereby positional information is detected. 
     In the resistive film type touch panel which has most commonly been used in some smartphones and tablet type information terminals, car navigation systems, mobile information terminals, etc., conduction between two opposing resistive films occurs by the touch panel being touched by a fingertip or a stylus pen, and positional information is detected by the partial pressure ratio of the resistance of the resistive films at the time being measured. 
     Also, in pen tablets that are used as peripheral devices for personal computers, and monitors having a touch-panel feature, the electromagnetic induction type touch panel is used. In the electromagnetic induction type touch panel, electromagnetic energy is detected on the touch-panel side by the touch panel (input pad or monitor) being touched by an electronic pen that generates a magnetic field, and positional information is detected thereby. 
     As just described, touch panels have a structure where a touch sensor is arranged on the front surface of a display device or a structure where a touch sensor is formed integrally with a display device. Therefore, a plate made of a transparent rigid material, such as glass or transparent acrylic, is generally used for the surface layer of a touch panel to improve the display quality of the display device and to protect the touch panel from physical pressure and scratches caused by contact with a stylus pen, a finger, etc. 
     On the other hand, the pen tips of stylus pens and electronic pens (hereinafter collectively referred to as “input pen”) for performing input operations on a touch panel are generally composed of a resin material. That is, they are composed of a rigid material similar to that of the surface layers of touch panels. Note that the pen tips of some input pens have a rubber tip (cap) attached thereto, or are made of a soft material such as compressed felt. Input pens such as these are described in detail in, for example, Japanese Patent Application Laid-open (Kokai) Publication No. 11-232022. 
     In the above-described case where the front surface of a touch panel and the pen tip of an input pen are composed of rigid materials, the user feels extreme firmness when performing an input operation using the input pen. In addition, the pen tip slips very easily. Therefore, there is a problem in that desirable handwritten input of fine letters, fine line drawings, etc. is difficult. 
     As the above-mentioned method of solving this problem, a rubber tip (cap) is attached to a pen tip. However, rubber material has high elasticity, which causes deformation and buckling to occur through repeated input operations. Accordingly, the product has a short life span and is not particularly user-friendly. In addition, in the other method compressed felt is used in a pen tip. However, because compressed felt has high abrasiveness, this product also has a short life span and is not particularly user-friendly. 
     SUMMARY OF THE INVENTION  
     In accordance with one aspect of the present invention, there is provided an input pen comprising: a pen tip member including a porous base member and a rubber material, wherein the rubber material is united with the porous base member within the porous base member, and partially exposed at least on surface of the porous base member. 
     The above and further objects and novel features of the present invention will more fully appear from the following detailed description when the same is read in conjunction with the accompanying drawings. It is to be expressly understood, however, that the drawings are for the purpose of illustration only and are not intended as a definition of the limits of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
       The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention, and together with the general description given above and the detailed description of the embodiments given below, serve to explain the principles of the invention. 
         FIG. 1A  and  FIG. 1B  are schematic diagrams showing an input pen according to a first embodiment of the present invention; 
         FIG. 2A  and  FIG. 2B  are schematic diagrams showing the pen tip of the input pen according to the first embodiment; 
         FIG. 3A  and  FIG. 3B  are schematic diagrams showing the pen tip of an input pen according to a second embodiment; and 
         FIG. 4A  and  FIG. 4B  are schematic diagrams showing structural examples of electronic devices to which the input pen of the present invention has been applied. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
     An input pen according to the embodiments of the present invention will hereinafter be described in detail. 
     First Embodiment  
       FIG. 1A  and  FIG. 1B  are schematic diagrams of an input pen according to a first embodiment of the present invention, of which  FIG. 1A  is a perspective view showing the overall structure of the input pen according to the first embodiment, and  FIG. 1B  is a perspective view showing a detailed structure of section IB shown in  FIG. 1A .  FIG. 2A  and  FIG. 2B  are schematic diagrams showing the pen tip of the input pen according to the first embodiment, of which  FIG. 2A  is a diagram of the pen tip of the input pen according to the first embodiment, and  FIG. 2B  is a cross-sectional view showing a detailed structure of section IIB shown in  FIG. 2A . 
     This input pen  1  according to the first embodiment includes a pen body  10  and a pen tip member  20 , as shown in  FIG. 1A  and  FIG. 1B . 
     The pen body  10  includes a rod-shaped, rectangular column-shaped, or circular column-shaped member that extends linearly in a certain direction. In at least one end of the pen body  10  in the extending direction, an attaching and fixing section  11  for detachably fixing the pen tip member  20  is provided. The attaching and fixing section  11  basically includes a guide groove  12  provided in the end portion of the pen body  10  and a fixing member  13  for fixing the pen tip member  20  to the pen body  10 . 
     The guide groove  12  is a linear groove section for attaching the pen tip member  20  to a predetermined area along the extending direction of the pen body  10 . The inner surface of the guide groove  12  is curved so that the side surface of the pen tip member  20  having a substantially circular column shape engages with the guide groove  12 . The fixing member  13  is a member for fixing the pen tip member  20  attached such that the side surface engages with the guide groove  12  to the pen body  10 . This fixing member  13  is structured such that the pen tip member  20  is adjustably attached to the pen body  10 . By the attaching and fixing section  11  being provided, the projection length of the tip end portion  21  (the portion that comes in contact with a touch panel) of the pen tip member  20  projecting from the pen body  10  is adjusted, and the pen tip member  20  is firmly fixed to the pen body  10 . 
     The pen tip member  20  includes a base member  22  having a substantially circular column shape, and at least one tip end portion  21  of the base member  22  which comes in contact with a touch panel has a hemispherical shape or a convex shape having a predetermined roundness. The base member  22  constituting the pen tip member  20  is a porous rigid body, for which a member has been adopted that has sufficient flexural strength so that deformation and buckling does not occur at least during an input operation performed on a touch panel by the input pen  1 . Specifically, the base member  22  is constituted by a member by which a resin material having the properties of rubber described later favorably impregnates the pore portion of the base member  22  when impregnation processing with the resin material is performed. For example, wood or foamed resin, or a member having equivalent or similar properties can be favorably adopted. 
     The resin material is formed such that a portion thereof is exposed on or adhesively covers at least the hemispherical surface of the tip end portion  21  of the pen tip member  20 . Specifically, in the structure of the first embodiment, impregnation processing with a material  23  having the properties of rubber has been performed on at least the tip end portion  21  of the pen tip member  20 , as shown in  FIG. 2B . That is, the porous base member  22  constituting the tip end portion  21  of the pen tip member  20  has been impregnated and united with the material  23  which has the properties of rubber and is in liquid form having relatively low viscosity. As a result, in this structure, the material  23  having the properties of rubber has been united with the base member  22  of the tip end portion  21  such that it is partially exposed on the surface of the tip end portion  21 . Here, when being united, the material (impregnation material)  23  impregnated into the porous base member  22  forms vesicles in the pore section of the base member  22 , as shown in  FIG. 2B . In addition, because the impregnation material  23  is being surrounded by the base member  22 , the impregnation material  23  and the base member  22  are united with high bonding strength. Portions of the vesicles of the impregnation material  23  are exposed on the surface of the tip end portion  21  of the pen tip member  20 . 
     In the first embodiment, common natural rubber, organic synthetic rubber (such as Nitrile Rubber [NBR] or Butadiene Rubber [BR]), non-organic synthetic rubber (such as silicone rubber or fluoro-rubber), or the like can be used as the above-described material (impregnation material)  23  having the properties of rubber. In addition, a resin material, such as an elastomer material, having the same or similar properties as the above-described rubber materials can also be used instead of the rubber materials. Note that the processing for impregnating a material having the properties of rubber into a porous base member can be easily actualized using, for example, a general-purpose vacuum impregnating device. 
     (Verification of Operational Effects) 
     Next, the operational effects of the above-described input pen according to the first embodiment will be verified in detail. 
     First, in an input operation that is performed on a touch panel using an input pen, a certain degree of a sense of friction (i.e., sliding of the pen tip) and a certain degree of flexibility (i.e., soft writing feeling) should preferably exist. That is, the sensation of the input operation should preferably be the same or similar to that when writing letters, line drawings, and the like on paper using a pen. The sense of friction and the flexibility that are felt when the user is writing letters, line drawings, and the like on paper using a pen are created as a result of “paper”, which has flexibility and in which fibers are complexly arranged, being used. That is, the sense of friction and the flexibility correspond to the writing feeling. 
     In a method for replicating this sensation (writing feeling) into an input operation that is performed on a touch panel using an input pen, for example, a special surface treatment is performed on the touch-panel surface so that the surface is roughen while having flexibility. However, in a case where this method is used to improve the sensation of an input operation, the transmittance of the touch panel is reduced due to the surface treatment. Accordingly, there is a problem in that the quality of display transmitted and viewed through the touch panel is reduced. 
     Also, in another method for replicating the sense of friction and the flexibility, which is felt when the user is writing letters and line drawings on paper using a pen, into an input operation that is performed on a touch panel using an input pen, a rubber material is used in the entire pen tip portion of the input pen, or a rubber cap is attached to the pen tip portion. However, there is a problem in this method in that, because the rubber material is an elastic body, deformation and buckling due to repeated stress occur by repeatedly performed input operations, which leads to cracks and eventually breakage. If the rigidity of the pen tip portion is increased to suppress the occurrence of buckling and cracks in the pen tip portion, another problem arises in that the sense of friction during an input operation is lessened. 
     Also, in another method for replicating the above-described sensation, for example, a material such as rigid compressed felt is used in the pen tip portion of an input pen. This rigid compressed felt can replicate some flexibility and some sense of friction when an input operation is performed on a touch panel despite having a rigid body. However, its durability and anti-worn property are inferior when touching and sliding back and forth the pen tip portion on a touch panel at a predetermined pressure. Accordingly, there is a problem in that the product life span becomes short, and therefore its practicality is poor. 
     In contrast, in the present embodiment, the state and the material of the surface of the touch panel are not changed. In the structure of the present embodiment, the tip end portion  21  of the pen tip member  20  of the input pen  1  is formed by a resin material having the properties of rubber being impregnated into the base member  22  having a porous rigid body such that the resin material is partially exposed on the surface of the tip end portion  21 , as described above. As a result, the above-described problems are solved. In the present embodiment, the writing feeling is soft and the pen tip does not easily slip during an input operation on a touch panel, whereby a sensation that is the same as or similar to that when writing letters, line drawings, and the like on paper using a pen can be actualized. Therefore, handwritten input of fine letters, fine line drawings, and the like can be favorably realized on a touch panel using an input pen. 
     That is, even in cases where an electronic device including a touch panel has a structure in which a transparent rigid material such as glass or transparent acrylic is used for the surface layer of the touch panel, the present embodiment actualizes a favorable writing feeling (sensations such as flexibility and a sense of friction) in an input operation by an input pen, while ensuring the transmittance of the display screen and suppressing the deterioration of the display quality. 
     Also, in the present embodiment, the tip end portion  21  of the pen tip member  20  having a porous rigid body is impregnated with a resin material having the properties of rubber, and the resin material is partially exposed on the surface of the tip end portion  21 . As a result, as compared to a structure where the entire pen tip portion is composed of a rubber material, the structure of the present embodiment can better ensure the rigidity (flexural strength) of the pen tip member  20  and the tip end portion  21  as well as ensuring the flexibility and the friction of rubber only by the interface where the input pen  1  and the touch panel come in contact with each other. Accordingly, in the present embodiment, the buckling, deformation, breakage, cracks, and the like of the pen tip of an input pen is prevented and a favorable writing feeling is actualized even when the pen tip is touched on a touch panel and slid back and forth at a predetermined pressure (writing pressure) during an input operation. 
     Moreover, in the present embodiment, a porous rigid body such as wood or foamed resin is used as the base member  22  constituting the pen tip member  20 , and a resin material having the properties of rubber is impregnated into at least the tip end portion  21  of the pen tip member  20 . Here, for comparison to the present embodiment, a structure will be verified in which a non-porous high-rigidity body, such as metal, is used for the base member of a pen tip member, and a material having the properties of rubber is adhered to or applied to the surface of the base member using a method such as insert molding or coating (referred to as a rubber film for convenience of explanation). In this comparative structure, bonding strength at the interface between the non-porous high rigidity body constituting the pen tip member and the rubber film is low, and the difference between their material properties is large. Therefore, there is a problem in that when touching and sliding back and forth the pen tip on a touch panel at a predetermined writing pressure, peeling easily occurs at the interface (bonded surface) between the rigid body and the rubber film. 
     In the present embodiment having the above-described structure, because of the impregnation material  23 , the porous base member  22  constituting the pen tip member  20  has rigidity similar to that of a rubber material, as compared to the above-described metal. That is, the rigidity difference between the respective materials is relatively small. In addition, the impregnation material  23  having the properties of rubber has been impregnated into and united with the base member  22  with high bonding strength such that it is partially exposed on the surface of the base member  22 . Therefore, in the present embodiment, peeling, etc. of the pen tip is prevented and a favorable writing feeling is actualized even when touching and sliding back and forth the pen tip on a touch panel at a predetermined writing pressure. 
     In the present embodiment, a method has been described in which a resin material (rubber material) is impregnated into at least the tip end portion  21  of the pen tip member  20  having a porous rigid body by a vacuum impregnating device. However, the present invention is not limited thereto. All that is required is that a resin material is strongly united with the pen tip member  20  having a porous rigid body, and partially exposed on or adhesively covers the surface of the tip end portion  21  of the pen tip member  20 . Therefore, various manufacturing methods can be used. For example, a method (surface coat processing) can be used in which a resin material (rubber material) is melted by a solvent or the like and used to coat the porous base member  22  having the same or similar properties as those of wood. Alternatively, a method can be used in which a resin material (rubber material) in liquid form is inserted into and injection molded in the porous base member  22 . By these methods as well, the operational effects of the above-described embodiment can be achieved. 
     Second Embodiment  
     Next, an input pen according to a second embodiment of the present invention will be described. 
       FIG. 3A  and  FIG. 3B  are schematic diagrams showing the pen tip of the input pen according to the second embodiment, of which  FIG. 3A  is a diagram showing the pen tip of the input pen according to the second embodiment, and  FIG. 3B  is a cross-sectional view showing a detailed structure of section IIIB shown in  FIG. 3A . 
     In the first embodiment described above, a structure in which the porous pen tip member  20  is impregnated with a resin material (rubber material) and the manufacturing method thereof has been described. In the second embodiment, a structure in which a fibrous material is mixed with a resin material and molded, and the manufacturing method thereof are described. 
     The input pen according to the second embodiment includes the pen body  10  and the pen tip member  20 , as in the case of the above-described input pen  1  of the first embodiment. Specifically, at least the tip end portion  21  of the pen tip member  20  is mixed and fabricated using a fibrous material  24 , such as glass fibers, carbon fibers, or metal fibers, and a material (mixing material)  25  having the properties of rubber, as shown in  FIG. 3A  and  FIG. 3B . That is, a material having the properties of rubber and relatively low viscosity is mixed and fabricated with the fibrous material  24  constituting the tip end portion  21  of the pen tip member  20 . As a result, the fibrous material  24  and the material having the properties of rubber become unified, and a structure is achieved in which a portion of the material having the properties of rubber is exposed on the surface of the tip end portion  21 . In this process, the material (mixing material)  25  mixed with the fibrous material  24  is held in the spaces between the fibers of the fibrous material  24 , and adhered to the fibrous material  24  surrounding the mixing material  25 . As a result, the mixing material  25  and the fibrous material  24  are united with high bonding strength. This mixing material  25  is partially exposed on the surface of the tip end portion  21  of the pen tip member  20 . 
     This structure also ensures the rigidity of the pen tip member  20  and the tip end portion  21  while ensuring the flexibility and the friction of rubber in only the interface where the input pen and a touch panel come in contact with each other, as in the case of the first embodiment. That is, in the second embodiment, a fibrous material, such as glass fibers, carbon fibers, or metal fibers, and a resin material having the properties of rubber are mixed and molded, and as a result strong fibers are present within the pen tip member  20 , whereby the rigidity and the flex resistance are further improved. Accordingly, in the second embodiment as well, the buckling, deformation, breakage, cracks, and the like of the pen tip of an input pen is prevented and a favorable writing feeling (flexibility and sense of friction) is actualized even when touching and sliding back and forth the pen tip on a touch panel at a predetermined pressure (writing pressure) during an input operation. 
     (Example of Application) 
       FIG. 4A  and  FIG. 4B  are schematic diagrams showing structural examples of electronic devices to which the input pen of the present invention has been applied, of which  FIG. 4A  is a perspective view of a structural example of a highly functional mobile phone, and  FIG. 4B  is a perspective view of a structural example of a personal computer. 
     As shown in  FIG. 4A  and  FIG. 4B , the input pen  1  according to the above-described embodiments can be favorably applied to various electronic devices. 
     In short, an electronic device  110  in  FIG. 4A , such as a smartphone or a mobile information terminal, includes a main body section  111 , a display section  112  including a resistive film type touch panel, an input operation section  113 , and an input pen (stylus pen)  114  having a structure equivalent to that of the input pen according to the above-described embodiments. In this example, during an input operation on the display section  112  by the input pen  114 , buckling, deformation, and the like of the pen tip is prevented and a favorable writing feeling is actualized. 
     Also, an electronic device  120  in  FIG. 4B , such as a desktop personal computer, includes a computer main body section  121 , a display section  122 , a keyboard  123 , an electromagnetic induction type pen tablet  124 , and an input pen (electronic pen)  125  having a structure equivalent to that of the input pen according to the above-described embodiments. In this example as well, during an input operation on the pen tablet  124  by the input pen  125 , any buckling, deformation, and the like of the pen tip is prevented and a favorable writing feeling is actualized. 
     In the above-described application examples, there are shown electronic devices using the resistive film type or electromagnetic induction type touch panel that are generally recognized as touch panels capable of pen input. However, the present invention is not limited thereto. That is, the present invention can also be applied to electronic devices using the capacitance type touch panel that is generally recognized as a touch panel incapable of touch input by using a conductive material for at least one of the base member  22  constituting the pen tip member  20  and the impregnation material in the above-described first embodiment, and setting the conductivity to be almost equivalent to that of the human body (finger). In this instance as well, the writing feeling of the input pen is soft and the pen tip slides so that the desired input operation can be favorably performed. Also, this desired input operation with a favorable writing feeling can be similarly performed in electric devices using a capacitance type touch panel, by using a conductive material for at least one of the fibrous material and the mixing material constituting the pen tip member  20  in the second embodiment, and setting the conductivity to be almost equivalent to that of the human body (finger). 
     While the present invention has been described with reference to the preferred embodiments, it is intended that the invention be not limited by any of the details of the description therein but includes all the embodiments which fall within the scope of the appended claims.