Patent Application
20120114863
The present invention relates to a lens holding jig to be used to apply an application liquid to a lens base material and a method of manufacturing a lens base material using the same.
As a lens holding jig to be used to apply an application liquid to a lens base material of a spectacle lens or the like, jigs described in, for example, Japanese Patent Laid-Open Nos. 2001-311914, 2004-268013, 2005-41703, 2008-9327, and 2003-71650 are known.
In the optical component holding jig described in Japanese Patent Laid-Open No. 2001-311914, an arm portion that retains an optical component is formed into a continuous three-dimensional shape conforming to the periphery of the optical component. Retainers are provided at the two ends and the center of the arm portion, respectively, to hold the outer periphery of the optical component at three points.
The lens holding jig described in Japanese Patent Laid-Open No. 2004-268013 includes two side holding portions that hold the two, left and right edges of a lens, and one lower holding portion that holds the lower edge of a cut end surface.
The holding jig disclosed in Japanese Patent Laid-Open No. 2005-41703 provides at least three holding portions on a frame curved into an almost circular shape surrounding the object to be held, like the optical component holding jig disclosed in Japanese Patent Laid-Open No. 2001-311914. These holding portions hold the outer periphery of the object to be held. At least one of the holding portions is attached to the frame via an elastically deformable biasing means.
In the holding jig described in Japanese Patent Laid-Open No. 2008-9327, two lens holding pieces hold one edge of a lens at two points, and one lens holding piece holds the other edge of the lens at one point.
The lens holding jig described in Japanese Patent Laid-Open No. 2003-71650 includes three arms and three holding portions attached to the distal ends of the arms, respectively, like the lens holding jig described in Japanese Patent Laid-Open No. 2004-268013. Two of the holding portions hold the two edges of the cut end surface of a lens, and the remaining one holds the lower edge of the cut end surface. The three arms are formed from wire rods. A biasing force is applied to one of them so to as make it relatively approach the remaining two arms.
However, in the holding jigs described in Japanese Patent Laid-Open Nos. 2001-311914, 2004-268013, 2005-41703, and 2008-9327, the application liquid readily collects on the holding portions, and the rate of defectives is high. That is, in these holding jigs, the lens holding surface of the holding portion is formed into a V shape to reduce the contact area with respect to the lens, and holds two edge portions of the cut end surface of the lens at two points. For this reason, when the lens holding surface holds the lens, an almost triangular closed space is formed between the lens holding surface and the cut end surface of the lens. When the lens immersed in the application liquid is pulled up, the closed space forms a portion where the application liquid collects after running down on the lens surface due to gravitation. Especially, in the lower holding portion that holds the lower edge of the lens, the application liquid collects in the closed space without running down, resulting in formation of an uneven film thickness portion of the application liquid. Since many application liquids are added with a leveling agent to form a uniform film on the lens base material, bubbles or films readily form. For this reason, bubbles form in the application liquid collected in the closed space. If the bubbles grow large and burst, or a film of the application liquid formed in the closed space by the surface tension breaks, the dropets stick to the lens surface again to cause an, application failure.
In addition, in Japanese Patent Laid-Open Nos. 2001-311914 and 2005-41703, when the holding jig is immersed in the application liquid, a closed space is formed between the lens and the frame. When the holding jig is pulled up, a film of the application liquid is formed in the closed space. If this film breaks and scatters, an application failure like that described above occurs.
In the holding jig described in Japanese Patent Laid-Open No. 2003-71650, the holding portion is formed into a triangular shape to minimize the contact area with respect to the lens, and its apex supports the lens at a point. However, in this holding portion as well, when the holding jig is pulled up from the application liquid, the application liquid runs down on the lens surface and collects on the surface of the holding portion. This causes an application failure, like the holding jigs described in Japanese Patent Laid-Open Nos. 2001-311914, 2004-268013, 2005-41703, and 2008-9327.
The present invention has been made in to solve the above-described conventional problems, and has as its object to provide a lens holding jig whose holding portion for holding a lens has such a shape or structure that prevents an application liquid from collecting so as to allow application in a uniform film thickness and prevent any application failure, and a method of manufacturing a lens base material using the same.
In order to achieve the above object, according to the present invention, there is provided a lens holding jig comprising a first arm, a second arm, and a third arm disposed on both sides of a lens base material to be held, a first side holding portion and a second side holding portion provided at lower ends of the first arm and the second arm, respectively, to hold left and right edges of a cut end surface of the lens base material, and a lower holding portion provided on the third arm to hold a lower edge of the cut end surface of the lens base material, wherein the lower holding portion comprises support surfaces that support lower edges of the cut end surface of the lens base material at two points, and an application liquid release portion running downward from the support surfaces, and when applying an application liquid to the lens base material, the first side holding portion, the second side holding portion, and the lower holding portion are immersed in the application liquid together with the first arm, the second arm, and the third arm.
According to the present invention, there is also provided a method of manufacturing a lens base material, comprising the steps of holding a cut end surface of a lens base material using a lens holding jig of the present invention, applying an application liquid to the lens base material by immersing the lens holding jig holding the lens base material in the application liquid, and solidifying the application liquid applied to the lens base material after withdrawing the lens holding from the application liquid.
In the lens holding jig according to the present invention and the method of manufacturing a lens base material using the same, the application liquid that has run down on the surface of the lens base material under its own weight to the support surfaces of the lower holding portion is released to the application liquid release portion. The application liquid does not collect or form a film in the closed space formed between the support surfaces of the lower holding portion and the cut end surface of the lens base material. This makes it possible to uniform the film thickness of the application liquid sticking to the cut end surface and thus prevent an application failure.
Effects other than these functions and effects of the present invention become apparent from the following description of embodiments and accompanying drawings of this specification.
In a preferred form of the lens holding jig according to the present invention, the lower holding portion is formed from a plate, and has an upper surface forming the support surfaces that support the lower edge of the cut end surface of the lens base material at the two points, and the application liquid release portion formed in at least one of an obverse surface and a reverse surface.
As a preferable form of the application liquid release portion, a vertically long groove, a hole, a combination of a groove and a hole, a projection, and the like are considerable.
When the application liquid release portion is formed from a long groove, a long hole, or a combination of a groove and a hole, working of the groove or hole is easy, and the lower holding portion can be manufactured at a low cost. That is, when the lower holding portion is formed from a plate, the groove or hole is formed using a cutter.
When the application liquid release portion is formed from a projection, the lower holding portion can be manufactured easily at a low cost, like the case of a groove or hole.
A preferred form of a lens holding jig according to the present invention is formed from a wire rod including a main body wire rod portion that forms the application liquid release portion, and lower edge support wire rod portions that support lower edges of the cut end surface of the lens base material at two points. The main body wire rod portion includes a pair of left and right vertical pieces almost parallel to each other, and a connection piece that connects the lower ends of the vertical pieces. A space proton surrounded by the vertical pieces and the connection piece forms the application liquid release portion. The lower edge support wire rod portions obliquely run upward and outward from the upper ends of the vertical pieces, respectively.
Such a lower holding portion can easily be manufactured by bending a wire rod into a U shape, a V shape, or an angular U shape and making wire rods (lower edge support wire rod portions) obliquely run upward and outward from the upper ends.
In a preferred form of the lens holding jig according to the present invention, the first arm and the second arm are arranged to oppose each other, and at least one of them freely opens/closes and is biased in a closing direction by biasing means.
Since at least one of the first arm and the second arm is biased in the closing direction, the two side holding portions can sandwich the left and right edges of the lens base material, enabling holding in a stable state.
In a preferred form of the lens holding jig and the lens base material manufacturing method the present invention, the lens base material is immersed in the application liquid to such a depth that forms no closed space with respect to the lens holding jig in the application Liquid.
If no closed space is formed in the application liquid between the lens base material and the lens holding jig, the application liquid does not collect or form a film in the closed space upon withdrawing the lens base material from the application liquid. It is therefore possible to prevent any defective without the influence of the collected application liquid on the film thickness of the application liquid applied to the lens surface or the possibility of droplet sticking to the lens surface due to film burst.
In a preferred form of the lens holding jig according to the present invention, the lens base material includes a plastic lens.
Referring to
As the application liquid 2, for example, a hard coat liquid (Ne=1.6 available from HOYA) for base material is used and stored in a hard coat tank in an environment of a temperature of 23° C. (20° C. to 25° C.), a humidity of 35% (20% to 50%), and a wind velocity of 0.5 m/min or less.
The lens holding jig 3 includes a holding jig main body 5, and a first arm 6A, a second arm 6B, and a third arm 6C which are attached to the holding jig main body 5. The holding jig main body 5 is formed from a metal plate. An inverted J-shaped hook portion 7 is integrally formed on the upper surface of one end portion so as to project upward.
The first arm 6A, the second arm 6B, and the third arm 6C are disposed to exist in the same vertical plane. The first arm 6A and the third arm 6C are disposed with their upper ends fixed on the left end side of the holding jig main body 5 in
The first arm 6A has its upper end fixed to the left end portion of the holding jig main body 5 by welding, soldering, or the like. The first side holding portion 8 of the first arm 6A is obliquely bent downward to point in the direction of the geometric center O of the lens base material 1. The distal end of the first side holding portion 8 is formed into a sharp pin shape to reduce the contact area with respect to the lens base material 1 and thus holds the cut end surface 1a at a point.
On the other hand, the second arm 6B is pivotally supported at its upper end portion within the same vertical plane including the first arm 6A, the second arm 6B, and the third arm 6C by a horizontal support shaft 10 attached to the right end portion of the holding jig main body 5. A twisted coil spring 11 serving as a biasing means applies, to the second arm 6B, a biasing force in the closing direction (clockwise in
The third arm 6C is arranged at a distance outside the first arm 6A. The third arm 6C includes a vertical arm portion 6C-1 having its upper end fixed to the left end of the holding jig main body 5 by welding or the like, and a tilted arm portion 6C-2 running obliquely downward from the lower end of the vertical arm portion 6C-1 and having its lower end located almost immediately under the lens base material 1. A lower holding portion 15 that holds the lower edge (lower edges S1 and S2) of the cut end surface 1a of the lens base material 1 at two points is attached to the lower end of the tilted arm portion 6C-2.
Referring to
When the support surfaces 16 of the lower holding portion 15 hold the cut end surface 1a of the lens base material 1, an almost triangular closed space 19 is formed between the cut end surface 1a and the support surfaces 16. The closed space 19 forms a portion where the application liquid 2 collects after running down on the cut end surface 1a from the optical surfaces 1b and 1c of the lens base material 1 to the support surfaces 16 of the lower holding portion 15. If the application liquid 2 collects in the closed space 19, the film thickness of the application liquid applied to the cut end surface is of the lens base material 1 becomes uneven, resulting in an application failure.
In the present invention, the lower holding portion 15 has an application liquid release portion 17 to release the application liquid 2 which may otherwise collect in the closed space 19. The application liquid release portion 17 is formed from a vertically long hole formed at the center of the lower holding portion 15 and are open to the obverse and reverse surfaces. The hole has its upper end open to the support surfaces 16 so as to communicate with the closed space 19. The application liquid release portion 17 has a cutting depth D of about 5 to 10 mm and a cutting width W of about 1 to 2 mm.
The shape and material of the lower holding portion 15 and the shape of the application liquid release portion 17 are not always specific, and can be changed variously in accordance with the cut end thickness of the lens base material 1, the viscosity of the application liquid 2, and the like. For example, various kinds of lower holding portions 15 as shown in
The pair of left and right lower edge support wire rod portions 23a and 23b obliquely run outward from the upper ends of the vertical pieces 22a and 22b, respectively, such that the upper surfaces form the support surfaces 16 that receive and support the lower edges S1 and S2 of the cut end surface 1a of the lens base material 1.
A method of manufacturing a lens base material using the above-described lens holding jig 3 will be explained next.
First, a lens base material 1 to which the application liquid 2 is to be applied and the lens holding jig 3 shown in
When immersing the lens base material 1 in the application liquid 2, the lens base material 1 is immersed in the application liquid 2 to such a depth that forms no closed space between the lens holding jig 3 and the lens base material 1 in the application liquid 2. That is, when the lens holding jig 3 is deeply immersed in the application liquid 2 to submerge the holding jig main body 5 in it, the cut end surface 1a of the lens base material 1, the first arm 6A, the second arm 6B, the third arm 6C, and the holding jig main body 5 form a closed space in the application liquid 2. For this reason, when the lens holding jig 3 is pulled up to withdraw the lens base material 1 from the application liquid 2, a film of the application liquid 2 is formed in the closed space. If this film bursts, some of the droplets stick to the cut end surface 1a or the optical surfaces 1b and 1c of the lens base material 1 to form an uneven film thickness, resulting in a defective. To prevent this, the immersion depth of the lens base material 1 in the application liquid 2 is controlled to such a depth that forms no closed space between the lens base material 1, the first arm 6A, the second arm 6B, the third arm 6C, and the holding jig main body 5 in the application liquid That is, the application is performed while immersing the lens base material 1 completely and only the lower half portions of the first arm 6A, the second arm 6B, and the third arm 6C in the application liquid 2 without immersing the holding jig main body 5 in it. In this immersion, no closed space is formed by the lens base material 1, the first arm 6A, the second arm 6B, the third arm 6C, and the holding jig main body 5 in the application liquid 2. Since no film is formed when the lens holding jig 3 is pulled up from the application liquid 2, any defective caused by burst of a film can be prevented.
After confirming that the lens base material 1 is completely immersed in the application liquid 2, the lens holding jig 3 is raised from the application liquid 2 at a withdraw speed of about 200 to 350 mm/min to withdraw the lens base material 1 from the application liquid 2. Upon withdrawing the lens base material 1 from the application liquid 2, the application liquid 2 sticking to the lens base material 1 runs down on the optical surfaces 1b and 1c due to gravitation and sticks to the lower holding portion 15.
In this case, on the conventional lens holding jig that includes no application liquid release portion 17, the application liquid 2 collects in the closed space 19 formed between the cut end surface 1a and the support surfaces 16 of the lower holding portion 15. If the application liquid solidifies in this state, the coating layer is thicker at the lower edge of the cut end surface 1a than at other portions.
In the present invention, however, since there is provided the application liquid release portion 17 running downward from the center of the support surfaces 16, the application liquid 2 which may otherwise collect in the closed space 19 between the cut end surface la and the support surfaces 16 can further be guided downward by the application liquid release portion 17. Since no application liquid 2 collects in the closed space 19, the application liquid 2 applied to the out end surface 1a and that running down from the closed space 19 to the application liquid release portion 17 can be separated. Hence, the application liquid 2 is applied to the cut end, surface 1a in a predetermined film thickness without being affected by the application liquid remaining in the closed space 19.
After precure, the lens base material 1 is heated to a predetermined temperature for a predetermined time to completely solidify the application liquid 2. With this process, a hard coat layer is formed on, for example, the cut end surface la and the optical surfaces 1b and 1c of the lens base material 1.
After formation of the hard coat layer, the lens base material 1 is detached from the lens holding jig 3. The lower edge of the cut end surface 1a of the lens base material 1, which was held by the lower holding portion 15 of the third arm 6C, is visually inspected, and the film thickness of the hard coat layer is evaluated based on the criterion for evaluation. If the film thickness is equal to or more than the criterion for evaluation, the lens base material is determined as a non-defective. If the film thickness is below the criterion for evaluation, the lens base material is determined as a non-defective. The manufacture of the lens base material 1 thus ends.
Experiments were conducted in which a hard coat liquid (Ne=1.6 available from HOYA) for base material was applied to lens base materials 1 using the lens holding jig 3 according to the present invention shown in
The experiments were carried out using four kinds of lens holding jigs 3 manufactured by forming a vertically long hole serving as an application liquid release portion 17 and setting a cutting depth D to 5 mm and 10 mm, a cutting width W to 1 mm and 2 mm, and an opening angle a of holding surfaces 16 to 90° and 120°. The components of the conventional lens holding jig are the same as those of the lens holding jig 3 according to the present invention except that the above-described application liquid release portion 17 is not provided on the lower holding portion.
As is apparent from Table 1, it was confirmed that film burst and residue on the cut end occurred in Comparative Examples 1 to 6, although neither film burst nor residue on the cut end occurred in Examples 1 to 6. This is supposed to be in itself the effect of providing the application liquid release portion 17.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2009-003575 2009 | Jan 2009 | JP | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/JP2010/050024 | 1/5/2010 | WO | 00 | 12/22/2011 |
