Patent Application
20160209945
The present invention relates to an input device including optical position detecting means.
A position sensor for optically sensing a pressed position has been hitherto proposed (see, for example, PTL 1). The position sensor includes a sheet-form optical waveguide including a plurality of linear light-path cores arranged in two orthogonal directions and a cladding which covers peripheral portions of the cores, and is configured such that light emitted from a light emitting element is inputted to one-side end faces of the cores to be transmitted through the cores and received on the other-side end faces of the cores by a light receiving element. When a part of a surface of the sheet-form position sensor is pressed with a finger or the like, core portions in the pressed part are compressed (the pressed core portions each have a sectional area reduced in a pressing direction) and, therefore, the light receiving element detects reduction in light receiving level in the pressed core portions. Thus, the position sensor senses the pressed position.
PTL 1: JP-A-HEI8(1996)-234895
When a user inputs a character or the like on the surface of the sheet-form position sensor of PTL 1 with the use of an input element such as a pen, however, the optical waveguide may be damaged by an input tip portion of the input element (a pen tip or the like) in some case. For easy deformation of the cores by the pressing and easy detection of the pressed position, more specifically, an over-cladding layer of the optical waveguide often has a smaller thickness (e.g., not greater than 200 μm) on the cores. In this case, if a pressing force applied onto the surface of the position sensor by the input tip portion of the input element is greater than a preset level (which is determined in consideration that an average pressing force to be applied by users is about 1.5 N), the input tip portion is liable to deeply sink into a square portion of the cladding surrounded by linear cores. This may crack the cladding portion, and the cracking may extend to the surrounding cores. When the input tip portion is moved by continuously applying the greater pressing force, the input tip portion may be caught by the linear cores, thereby cracking the cores. The cracked cores cannot properly transmit the light, so that the position sensor loses its function.
In view of the foregoing, it is an object of the present invention to provide an input device including an optical waveguide free from cracking of cores which may otherwise occur when an input tip portion of an input element is pressed against the input device or moved on the input device.
To accomplish the aforementioned object, an input device according to the present invention includes: a sheet-form optical waveguide including a plurality of linear cores arranged in a lattice pattern, dummy patterns respectively provided in portions surrounded by the linear cores, and a sheet-form under-cladding layer and a sheet-form over-cladding layer holding the cores and the dummy patterns therebetween; a light emitting element connected to one-side end faces of the cores of the optical waveguide; and a light receiving element connected to the other-side end faces of the cores; wherein light emitted from the light emitting element is transmitted through the cores of the optical waveguide and received by the light receiving element; wherein a surface region of the over-cladding layer corresponding to a plurality of linear cores arranged in a lattice-pattern is defined as an input region, and a pressed position at which the input region is pressed with an input tip portion of an input element is specified based on light transmission amounts of the cores changed by the pressing; wherein the dummy patterns and the cores each have an elasticity modulus that is not less than the elasticity moduli of the under-cladding layer and the over-cladding layer, whereby the cores are prevented from being cracked when the input region is pressed with the input tip portion.
The inventors of the present invention conducted studies on the configuration of the optical waveguide in order to prevent the cores of the optical waveguide from being cracked when the input tip portion of the input element (a pen or the like) is pressed against the input device and moved on the input device to input a character or the like on the input device by means of the input element, even if the over-cladding layer is thin and has a thickness of not greater than 200 μm, e.g., a thickness of 10 to 100 μm, on the cores. In the studies, the inventors conceived an idea that dummy patterns irrelevant to light transmission are provided in the portions surrounded by the linear cores and are held together with the cores between the sheet-form under-cladding layer and the sheet-form over-cladding layer, and further conducted studies. As a result, the inventors found that, where the elasticity moduli of the cores and the dummy patterns are not less than the elasticity moduli of the under-cladding layer and the over-cladding layer, the provision of the dummy patterns prevents the input tip portion (a pen tip or the like) from deeply sinking when a character or the like is inputted by applying a greater pressing force by means of the input element (the pen or the like). In addition, the inventors found that the over-cladding layer and the under-cladding layer are free from the cracking, and the cores are also free from the cracking. Further, the inventors found that, even if the input tip portion is moved in this state, the provision of the dummy patterns prevents the input tip portion from being caught by the cores and the cores are free from the cracking, and attained the present invention.
In the inventive input device, the dummy patterns are provided in the portions surrounded by the linear cores arranged in the lattice pattern, and are held together with the cores between the sheet-form under-cladding layer and the sheet-form over-cladding layer. Further, the elasticity moduli of the dummy patterns and the cores are not less than the elasticity moduli of the under-cladding layer and the over-cladding layer. With the provision of the dummy patterns, therefore, the portions surrounded by the linear cores are not significantly deformed to deeply sink even if the great pressing force is applied to the surrounded portions by the input tip portion of the input element. Thus, the cores are prevented from being cracked. Even if the input tip portion is moved in this state, the provision of the dummy patterns substantially prevents the input tip portion from being caught by the cores, so that the cores are free from the cracking.
Particularly, spacings between peripheral surfaces of the dummy patterns and opposed side surfaces of the cores may be each 10 to 300 μm. In this case, even if the input tip portion of the input element is very thin, the input tip portion is prevented from deeply sinking into the spacings. Therefore, the cores are free from the cracking.
The optical waveguide may be configured such that the cores and the dummy patterns are embedded in a surface of the under-cladding layer with top surfaces thereof being flush with the surface of the under-cladding layer, and the over-cladding layer covers the surface of the under-cladding layer, the top surfaces of the cores and the top surfaces of the dummy patterns. In this case, the configuration of the optical waveguide and the deformation suppressing effect of the dummy patterns synergistically make it easier to detect the pressed position at which the input region is pressed with the input tip portion of the input element, and improve the writing feeling.
Next, embodiments of the present invention will be described in detail with reference to the drawings.
In the optical waveguide W, the dummy patterns A and the cores 2 each have an elasticity modulus that is not less than the elasticity moduli of the under-cladding layer 1 and the over-cladding layer 3. For example, the elasticity moduli of the dummy patterns A and the cores 2 are set within a range of 1 to 10 GPa. The elasticity modulus of the over-cladding layer 3 is set within a range of 0.1 to 10 GPa, and the elasticity modulus of the under-cladding layer 1 is set within a range of 0.1 to 1 GPa. If the elasticity modulus of the cores 2 is less than the elasticity moduli of the under-cladding layer 1 and the over-cladding layer 3, the peripheries of the cores 2 will become too hard. Therefore, the cores 2 are not properly deformed with respect to the pressing, making it difficult to accurately detect the pressed position. The provision of the dummy patterns A is a major characteristic feature of the present invention.
Even if a great pressing force is applied to the input region on the surface of the over-cladding layer 3 when a character or the like is inputted by means of an input element such as a pen, the provision of the dummy patterns A prevents the portions surrounded by the linear cores 2 from being significantly deformed to deeply sinking. As a result, the over-cladding layer 3 and the under-cladding layer 1 are free from the cracking, and the cores are also free from the cracking. Even if an input tip portion (a pen tip or the like) of the input element is moved in this state, the input tip portion (the pen tip or the like) is less liable to be caught by the cores 2 with the provision of the dummy patterns A. As a result, the cores 2 are free from the cracking.
In this embodiment, spacings B between peripheral side surfaces of the dummy patterns A and opposed side surfaces of the cores 2 are small in a range of 10 to 300 μm. Even if the input tip portion (the pen tip or the like) is very thin, the input tip portion is prevented from deeply sinking into the spacings B. As a result, the cores 2 are free from cracking.
In this embodiment, the dummy patterns A are formed from the same photosensitive resin as the cores 2. The dummy patterns A and the cores 2 are simultaneously formed by a photolithography method using a single photomask. If the dummy patterns A were formed in contact with the cores 2 (with a spacing of 0 μm), light transmitted through the cores 2 would go into the dummy patterns A and, therefore, proper light transmission would be impossible. For this reason, it is necessary to provide the spacings B. If the spacings B are too small, it will be difficult to form the spacings B. If the spacings are too great, the input tip portion (the pen tip or the like) is liable to deeply sink into the spacings B. In view of this, the spacings B are each set in a range of 10 to 300 μm as described above in this embodiment.
In this embodiment, the cores 2 arranged in the lattice pattern and the rectangular dummy patterns A are embedded in a surface of the sheet-form under-cladding layer 1 with top surfaces thereof being flush with the surface of the under-cladding layer 1, and the sheet-form over-cladding layer 3 covers the surface of the under-cladding layer 1 and the top surfaces of the cores 2 and the top surfaces of the dummy patterns A. Thus, the optical waveguide W is configured in a sheet form. In the optical waveguide W having this specific configuration, the over-cladding layer 3 has a uniform thickness, and the dummy patterns
A have a deformation suppressing effect. This makes it easy to sense the pressed position at which the input region is pressed with the input tip portion of the input element, thereby improving the feeling of the writing with the input element. Where the optical waveguide
W has the aforementioned configuration, the under-cladding layer 1 has a thickness of, for example, 20 to 2000 μm, and the cores 2 and the dummy patterns A each have a thickness of, for example, 5 to 100 μm. Further, the over-cladding layer 3 has a relatively small thickness, e.g., a thickness of 1 to 200 μm, preferably 10 to 100 μm. Thus, the pressed position at which the input region is pressed with the input element (the pen or the like) can be easily detected.
As shown in a sectional view of
When the pressing with the input tip portion 10a is removed (the inputting ends), the under-cladding layer 1, the cores 2 and the over-cladding layer 3 are restored to their original states (see
The input device further includes a CPU (central processing unit) (not shown) for controlling the input device. The CPU incorporates a program which determines the position and the movement locus of the input tip portion 10a (the pen tip or the like) based on the reduction in light receiving level detected by the light receiving element 5. For example, data indicative of the position and the movement locus of the input tip portion 10a is stored (memorized) as electronic data in storage means such as a memory.
Further, information such as notes stored (memorized) in the storage means can be reproduced (displayed) on a reproduction terminal (a personal computer, a smartphone or a tablet terminal), or stored in the reproduction terminal. In this case, the reproduction terminal and the input device are connected to each other via a connection cable such as a micro USB cable. The information is stored (memorized) in a versatile file form such as a pdf form in the storage means (memory).
Next, a method for fabricating the optical waveguide W will be described. Exemplary materials for the under-cladding layer 1, the cores 2, the over-cladding layer 3 and the dummy patterns A of the optical waveguide W include photosensitive resins and thermosetting resins. The optical waveguide W may be fabricated by a method suitable for the materials to be used. First, as shown in
The refractive index of the cores 2 is set greater than the refractive indices of the under-cladding layer 1 and the over-cladding layer 3. The elasticity moduli and the refractive indices are adjusted by controlling the selection of the types of the materials and the formulations of the materials.
In the aforementioned embodiment, the dummy patterns A each have a rectangular shape, but may have other shape, e.g., a round shape or a polygonal shape.
In the aforementioned embodiment, the dummy patterns A and the cores 2 are simultaneously formed from the same materials, but the material for the dummy patterns A may be different from the material for the cores 2. It is not necessary to simultaneously form the dummy patterns A and the cores 2. Particularly, where the dummy patterns A are made of a material that is not transparent to light traveling through the cores 2, the dummy patterns A may be provided in contact with the cores 2.
In the aforementioned embodiment, the top surfaces of the dummy patterns A are located at the same height level as the top surfaces of the cores 2 (are flush with the top surfaces of the cores 2), and this arrangement is preferred. As long as satisfying the condition to prevent cracking of the cores 2, it is also possible to configure the optical waveguide such that the top surfaces of the dummy patterns A may be located at a lower height level or a higher height level than the top surfaces of the cores 2.
In the aforementioned embodiment, the dummy patterns A and the cores 2 have the same thickness, and this arrangement is preferred. As long as satisfying the condition to prevent cracking of the cores 2, it is also possible to configure the optical waveguide such that the thickness of the dummy patterns A may be different from the thickness of the cores 2.
The optical waveguide W may have a construction different from that of the aforementioned embodiment. As shown in a sectional view of
As shown in a sectional view of
The input element 10 is merely required to be able to properly press the optical waveguide W as described above, and examples of the input element 10 include a writing implement capable of writing on a paper sheet with ink or the like and a simple rod that is not adapted for writing with ink.
In the aforementioned embodiment, intersecting core portions of the linear cores 2 arranged in the lattice pattern each continuously extend in four intersecting directions as shown in an enlarged plan view of
Whereat least one part of the intersecting core portion is discontinuous in at least one of the intersecting directions from the other part of the intersecting core portion as shown in
Next, inventive examples will be described in conjunction with a comparative example. It should be understood that the invention be not limited to the inventive examples.
Component (a): 75 parts by weight of an epoxy resin (YL7410 available from Mitsubishi Chemical Corporation)
Component (b): 25 parts by weight of an epoxy resin (JER1007 available from Mitsubishi Chemical Corporation)
Component (c): 2 parts by weight of a photo-acid generator (CPI101A available from San-Apro Ltd.)
An under-cladding layer formation material and an over-cladding layer formation material were each prepared by mixing Components (a) to (c).
[Core/Dummy Pattern Formation Material]
Component (d): 75 parts by weight of an epoxy resin (EHPE3150 available from Daicel Corporation)
Component (e): 25 parts by weight of an epoxy resin (KI-3000-4 available from Toto Chemical Industry Co., Ltd.)
Component (f): 1 part by weight of a photo-acid generator (SP170 available from ADEKA Corporation)
Component (g): 50 parts by weight of ethyl lactate (solvent available from Wako Pure Chemical Industries, Ltd.)
A core/dummy pattern formation material was prepared by mixing Components (d) to (g).
[Fabrication of Optical Waveguides]
An over-cladding layer was first formed on a surface of a glass substrate with the use of the over-cladding layer formation material by a spin coating method. The over-cladding layer had a thickness of 25 μm and an elasticity modulus of 3 MPa. The elasticity modulus was measured by means of a viscoelasticity measuring apparatus (RSA3 available from TA Instruments Japan Inc.)
Lattice-pattern linear cores and rectangular dummy patterns were simultaneously formed on a surface of the over-cladding layer with the use of the core/dummy pattern formation material by a photolithography method using a single photomask. The cores and the dummy patterns each had a thickness of 50 μm and an elasticity modulus of 2 GPa. A spacing between the dummy patterns and the cores is shown below in Table 1. In the Comparative Example, the dummy patterns were not formed.
Then, an under-cladding layer was formed over an upper surface of the over-cladding layer with the use of the under-cladding layer formation material by a spin coating method to cover the cores and the dummy patterns. The under-cladding layer had a thickness of 25 μm and an elasticity modulus of 3 MPa.
In turn, the over-cladding layer was separated from the glass substrate. Then, the under-cladding layer was bonded to a surface of an aluminum plate with an adhesive agent. In this manner, optical waveguides (see
[Evaluation of Optical Waveguides]
Characters were written on ten surface portions of the over-cladding layer with a ballpoint pen (having a tip diameter of 0.5 mm) by applying a load shown below in Table 1 on the surface portions by a tip of the ballpoint pen. As a result, an optical waveguide free from cracking in the over-cladding layer, the cores and the under-cladding layer and ensuring good writing feeling was rated as excellent and marked with “∘∘” in Table 1, and an optical waveguide free from cracking in the over-cladding layer, the cores and the under-cladding layer, but failing to ensure good writing feeling was rated as acceptable and marked with “∘” in Table 1. Further, an optical waveguide suffering from cracking in any of the over-cladding layer, the cores and the under-cladding layer was rated as unacceptable and marked with “x” in Table 1.
The results shown above in Table 1 indicate that the optical waveguides of Examples 1 to 4 were excellent in cracking resistance to a great pressing force. Particularly, the optical waveguides of Examples 1 to 3 ensured excellent writing feeling. Further, the optical waveguide of the Comparative Example was inferior in cracking resistance. Differences in the results are attributable to the presence or absence of the dummy patterns, and the size of the spacing between the dummy patterns and the cores.
The optical waveguides of Examples 1 to 4 each had a construction as shown in the sectional view of
In Examples 1 to 4, the top surfaces of the dummy patterns were located at the same height level as the top surfaces of the cores (were flush with the top surfaces of the cores). Even where the height level of the top surfaces of the dummy patterns was different from the height level of the top surfaces of the cores, the resulting optical waveguides were free from the cracking of the cores, but impaired the writing feeling. In Examples 1 to 4, the dummy patterns and the cores had the same thickness. Where the thickness of the dummy patterns was different from the thickness of the cores, the resulting optical waveguides were free from the cracking of the cores, but impaired the writing feeling.
Further, where a rubber layer having a thickness of 20 to 2000 μm and an elasticity modulus of 0.1 M to 1 GPa was provided on a lower surface of the under-cladding layer of each of the optical waveguides, evaluation results had substantially the same tendency as in Examples 1 to 4.
While specific forms of the embodiments of the present invention have been shown in the aforementioned inventive examples, the inventive examples are merely illustrative of the invention but not limitative of the invention. It is contemplated that various modifications apparent to those skilled in the art could be made within the scope of the invention.
The inventive input device is free from the cracking of the optical waveguide thereof, and properly functions for its purpose even if the input device is pressed with a great pressing force when information such as a character is inputted by means of an input element such as a pen.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2013-200514 | Sep 2013 | JP | national |
| 2014-101369 | May 2014 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2014/068665 | 7/14/2014 | WO | 00 |
