JP2000210614A - Optical device and formation of coating film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical device on which a uniform coating film can be formed and a film forming method. SOLUTION: For example, a plastic lens 1 produced by an injection molding has a gate part 5 on the outer periphery. A groove 6 is formed at the side edge 2 and the gate part 5 of the lens 1. The lens 1 is dipped in a coating liquid by supporting the gate part 5 with a supporting tool and is drawn up from the coating liquid. At this time, the groove 6 functions as the flow passage of the excess coating liquid stuck to the lens 1. Next, the coating liquid stuck to the lens 1 is cured, for example, by the ultraviolet ray irradiation to form the coating film. After that, the supporting tool is detached from the lens 1 and the gate part 5 is cut and removed. The uniform coating film is formed on the 1st surface 3 and the 2nd surface 4 of the lens 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical element such as a lens and a method for forming a coating on a surface of the optical element.

[0002]

2. Description of the Related Art A hard coat layer (coating film) is formed on the surface of various lenses in order to prevent scratches.
Conventionally, this hard coat layer is formed as follows.

As shown in FIG. 8, a lens 10 is immersed in a coating solution 80 while both sides of the lens 10 are supported (sandwiched) by a supporter 12 for pulling up, and the lens 10 is pulled up from the coating solution 80. The applied coating liquid 80 is cured to form a coating film on the lens surface.

However, in this method, the lens 10
When the liquid is pulled out of the coating liquid 80, the edge 11 of the lens 10, especially the edge 11 located below, is caused by liquid dripping (movement of the liquid downward) due to gravity, surface tension of the liquid, and the like.
The coating liquid remains on the film, and a swelling of the coating film (a coating film thicker than the designed film thickness) 14 occurs.

[0005] If such a swelling 14 of the coating film is formed on the edge portion 11 of the lens 10, the outer diameter (length and width) of the lens 10 increases by the film thickness, and it is difficult to mount the lens 10 on a lens holder or the like. May be.

Further, under the lens 10, since the coating liquid is accumulated by the movement due to gravity, not only the edge portion 11, but also the surface of the lens 10 in the vicinity thereof (the surface of the effective area).
The swelling 13 of the coating film occurs on the surface.

Further, the swelling 13 of the coating film on the surface of the lens 10 also occurs near the portion where the support 12 is in contact with the lens 10.

When the bulge 13 of the coating film is formed, the effective area of the lens 10 has a shape different from the originally designed shape, and the optical characteristics of the lens 10 may be impaired.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to provide an optical element capable of forming a uniform coating film and a method for forming the coating film.

[0010]

This and other objects are achieved by the present invention which is defined below as (1) to (16).

(1) An optical element used by forming a coating film on the surface, wherein a groove serving as a flow path of a coating liquid when forming the coating film is formed at an edge of the optical element. An optical element characterized in that:

(2) The optical element according to (1), wherein the groove is formed over substantially the entire periphery of the edge of the optical element.

(3) The optical element is a lens,
The optical element according to the above (1), wherein the groove is formed in an edge portion of the lens.

(4) When the width of the groove is w and the depth of the groove is d, w = 0.1 to 1.0 mm and d = 0.1 to 1.5 mm. The optical element according to any one of 3).

(5) The optical element according to any one of (1) to (4), wherein the optical element is a plastic molded product.

(6) The optical element according to (5), wherein the groove is formed at the same time when the optical element is molded.

(7) The optical element according to the above (5) or (6), which has a gate portion formed at the time of molding.

(8) The optical element according to (7), wherein the groove is also formed in the gate portion.

(9) A method for forming a coating film on the optical element according to the above (7) or (8), wherein the coating film is formed while supporting the gate portion with a support. A method for forming a coating film, characterized in that:

(10) A method for forming a coating film on the optical element according to the above (7) or (8),
A method for forming a coating film, comprising forming a coating film while supporting the gate portion with a support, and then removing all or a part of the gate portion.

(11) The method for forming a coating film according to the above (9) or (10), wherein the coating film is formed by a dipping method.

(12) The method for forming a coating film according to the above (11), wherein the optical element is pulled out of the coating solution with the gate portion being directed downward.

(13) The above-mentioned (1), wherein the lifting speed of the object to be coated from the coating solution is 10 to 1000 mm / min.
The method for forming a coating film according to 1) or (12).

(14) The method for forming a coating film according to any one of the above (9) to (13), wherein the coating film is a hard coat layer.

(15) The viscosity of the coating solution is 1 to 100
The method for forming a coating film according to any one of the above (9) to (14), which has 0 cps (25 ° C.).

(16) The temperature of the coating solution is 5 to 40 ° C.
The method for forming a coating film according to any one of the above (9) to (15).

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an optical element and a method of forming a coating film according to the present invention will be described in detail with reference to preferred embodiments shown in the accompanying drawings.

The type of the optical element (optical component) of the present invention is as follows.
There is no particular limitation, and examples thereof include various optical components such as various lenses, prisms, mirrors, beam splitters, optical filters, polarizing plates, window members, and wristwatch glasses.
In the following embodiments, a case where a lens is used as an optical element will be described as an example.

FIGS. 1, 2 and 3 are a front view, a side view and a bottom view, respectively, showing an embodiment of a lens 1 which is an optical element of the present invention.

As shown in these figures, the lens 1 has a first surface 3 and a second surface 4 on both surfaces thereof. An edge portion 2 is formed at the outer peripheral end (all around) of the lens 1.

In this embodiment, the lens 1 is, for example,
Various types such as polymethyl methacrylate (PMMA), polycarbonate (PC), polystyrene (PS), diethylene glycol bisallyl carbonate, acrylonitrile-styrene copolymer, methyl methacrylate-styrene copolymer, poly (-4-methylpentene-1) and the like It is made of plastic material (optical plastic).

The lens 1 is a plastic molded product manufactured by, for example, injection molding using the above-mentioned plastic material. In the lens 1, a gate portion 5 corresponding to a gate (resin injection port) for injecting a molten resin into a mold (mold) during injection molding is formed integrally with the lens 1. In the illustrated example, a rod-shaped gate portion 5 is provided.
Are formed integrally with a part of the edge portion 2 of the lens 1.

The gate portion 5 is an unnecessary portion which does not contribute to the optical function of the lens 1, and is cut and removed later.

In the illustrated embodiment, the thickness (edge thickness) t of the edge portion 2 is substantially the same over the entire circumference, but the edge thickness t may be partially changed.

In the edge portion 2 of the lens 1, a groove 6 (shown by hatching in FIGS. 2 and 3) which functions as a flow path of the coating liquid 8 is formed when a coating film 9 is formed as described later. Have been. The groove 6 is formed continuously over substantially the entire periphery of the edge portion 2.

The groove 6 is preferably formed at the center of the edge portion 2 in the lens thickness direction, as shown in FIGS. Thereby, the coating liquid 8 on the edge portion 2 can flow down evenly.

The groove 6 is formed not only in the edge portion 2 but also in the edge portion 2.
It is also formed on both side surfaces of the gate portion 5. The groove 6 formed in the gate portion 5 is connected to the groove 6 formed in the edge portion 2. By forming the groove 6 also in the gate portion 5 as described above, the coating liquid 8 is discharged, particularly, the coating liquid 8 on the edge portion 2 located below (the portion where the gate portion 5 is formed). Is made more smoothly.

In the gate section 5, the gate section 5
The groove 6 may be formed on the front and / or back of the.

The edge 6 and the groove 6 of the gate 5
May be formed by post-processing, but is preferably formed at the same time as the lens 1 is formed. Thus, an increase in the number of manufacturing steps of the lens 1 can be prevented. As a specific method of forming the groove 6, a protrusion corresponding to the shape of the groove 6 may be formed in the mold of the lens 1 or the resin injection path.

In the illustrated embodiment, the cross-sectional shape of the groove 6 is rectangular, but is not limited to this.
It may be V-shaped, W-shaped, U-shaped, or the like.

In the illustrated embodiment, one groove 6 is formed along the outer peripheral direction of the edge portion 2, but two or more grooves 6 may be formed. When a plurality of grooves 6 are formed, a relatively shallow groove 6 can sufficiently secure the cross-sectional area of the flow path of the coating liquid 8.

The width and depth of the groove 6 are not particularly limited, but as shown in FIG. 3, the width of the groove 6 is w and the depth of the groove 6 is d.
It is preferable that the following relationship be satisfied. Note that w and d may be different depending on the location where they are formed, and in that case, they are average values.

It is preferable that w = about 0.1 to 1.0 mm, and it is more preferable that w = about 0.3 to 0.8 mm. It is preferable that d = about 0.1 to 1.5 mm.
= 0.3 to 1.0 mm is more preferable.

If w or d is too small, the function as a flow path may not be sufficiently exhibited depending on the type, viscosity, etc. of the coating liquid 8, and if d is too large, especially in the case of a minute lens. This may affect the effective area of the lens 1.

Next, a method for forming a coating film on the surface of the lens 1 will be described.

4 and 5 are front views showing an embodiment of the method for forming a coating film of the present invention, FIG. 6 is a sectional side view of the lens after the coating film is formed, and FIG. It is sectional side view which shows the shape of the coating film after removing a part.

The lens 1 is supported by a support (pull-up support) 7 during the coating film forming operation described below. As shown in FIGS. 4 and 5, for example, the support 7 has an L-shaped bent shape, and its tip end is fixed to the gate 5 by, for example, pinching, fitting, bonding, or the like. It can be supported.

The location where the lens 1 is supported by the support 7 is the gate section 5. That is, the posture of the lens 1 is adjusted so that the gate unit 5 is positioned below, and the lower end of the gate unit 5 is supported by the support 7 (see FIG. 4).

In this state, as shown in FIG.
Is immersed in a coating liquid (immersion liquid) 8 containing the components of the coating film 9.

The coating liquid 8 is not particularly limited, and includes, for example, a coating liquid for forming a hard coat layer, an antireflection film, a reflection increasing film, a protective layer, a conductive layer, a coloring layer, an LB film, and the like. .

In the case of a coating solution for forming a hard coat layer, the main components differ depending on the constituent materials of the lens 1 and the like.
For example, in the case of a polymethyl methacrylate (PMMA) lens, an acrylic hard coat liquid (containing silica)
Is preferably used.

The coating liquid 8 may contain various curing agents such as an ultraviolet curing agent.

Further, the coating liquid 8 may contain various additives. Examples of the additive include a filler such as silica.

The viscosity of the coating liquid 8 is not particularly limited, but is preferably about 1 to 1000 cps (25 ° C.).
It is more preferably about 1 to 100 cps (25 ° C.). If the viscosity is too high, the formed coating film 9 tends to be uneven.

The temperature of the coating liquid 8 is not particularly limited, but is preferably about 5 to 40 ° C., and preferably 15 to 25 ° C.
It is more preferable that the temperature is about ° C. If the temperature is too high, it is difficult to handle, and if the temperature is too low, it is difficult to handle because of the influence of water.

Next, as shown in FIG. 5, the lens 1 supported by the support 7 is pulled up from the coating liquid 8. At this time, the posture of the lens 1 is such that the gate portion 5 is directed downward in the vertical direction.

The surplus coating liquid 8 adhering to the first surface 3 and the second surface 4 of the lens 1 flows down along these surfaces, and the coating liquid 8 adhering to the edge 2 Flows down in the groove 6 formed in the groove.

The coating solution 8 flowing down to the lower portion of the lens 1 in this manner is formed on the surface of the gate portion 5, particularly on the gate portion 5 without stopping at the edge portion 2 located below the lens 1. It flows down to the lower part of the gate part 5 through the groove 6.

As described above, the surplus coating liquid 5 is supplied to the gate 5
Can escape through the edge portion, so that the swelling of the coating film as described above is prevented from being formed on the edge portion 2 and its periphery. As a result, the optical characteristics are not impaired by the change in the shape of the lens 1, and when the lens 1 is mounted on a supporting portion or a mounting portion such as a lens holder, the mounting can be performed properly and reliably.

The lifting speed from the coating solution 8 is not particularly limited, but is preferably about 10 to 1000 mm / min, more preferably about 150 to 350 mm / min. If the pulling speed is too high, the uniformity of the formed coating film 9 will decrease, and if the pulling speed is too low, the productivity will decrease.

After the lens 1 is pulled out of the coating liquid 8, the coating liquid 8 adhering to the surface of the lens 1 moves downward by gravity and further passes through the surface of the gate portion 5 and the groove 6. It flows down. Then, it stays near the lower part of the gate section 5. Therefore, the thickness of the coating film 9 becomes thick near the lower part of the gate portion 5, and a bulge 91 occurs (see FIG. 6). However, this part will later be
Along with the swelling 9 of such a coating film.
1 may be formed.

Since the lens 1 is in contact with the supporting member 7 only through the gate portion 5, a bulge 91 of the coating film is formed in another portion of the lens 1 due to the contact with the supporting member 7. The first surface 3 and the second surface 3 of the lens 1
The coating 9 formed on the surface 4 has a uniform thickness.

Next, the coating liquid 8 adhering to the surface of the lens 1
To cure. Thereby, the coating film 9 is formed (FIG. 3).
reference).

The method of curing the coating film is appropriately determined according to the type and composition of the coating solution. For example, a method of drying a wet coating film, a method of heating and curing the coating film,
A method of irradiating the coating film with light such as ultraviolet rays, an electron beam, radiation, or the like can be used.

Even if the coating liquid 8 adheres to the edge portion 2 before the coating liquid 8 is cured, the coating liquid is absorbed in the groove 6, so that the coating 9 is applied to the edge portion 2. Even if it is formed, its thickness becomes extremely thin (see FIGS. 6 and 7). Therefore, when the lens 1 is mounted on a support portion or a mounting portion such as a lens holder, the mounting can be performed properly and reliably.

When the curing of the coating film 9 is completed, the lens 1 is removed from the support 7.

Next, the gate section 5 is cut and removed along the cutting line 51. As a result, as shown in FIG. 7, the lens 1 in which the first and second surfaces 3 and 4 have the uniform and uniform coating film 9 formed thereon is obtained.

The gate portion 5 may be removed entirely, or may be removed leaving a part (a portion near the edge portion 2).

Since the bulge 91 of the coating film 9 formed below the gate portion 5 is removed together with the cutting and removal of the gate portion 5, an additional operation for removing the bulge 91 of the coating film 9 is added. No need. Therefore, the method for forming a coating film of the present invention has an advantage that a uniform and uniform coating film 9 can be formed by a simple method without complicating the operation steps.

According to the method for forming a coating film as described above, a uniform and uniform coating film 9 is formed on the first surface 3 and the second surface 4 of the lens 1.
Is formed, it is possible to prevent the optical characteristics of the lens 1 from changing due to a change in the shape of the effective area portion (portion functioning as a lens) of the lens 1.

In the present invention, the type of the lens 1 is not particularly limited. For example, a lens constituting a photographic optical system of a camera or a video camera, a lens constituting a finder optical system, a telescope, binoculars, a microscope, a projector ( Projectors), lenses used in copiers, laser printers, optical pickups (optical heads for optical disks, magneto-optical disks)
The present invention can be applied to small lenses, minute lenses used for endoscopes and the like, lenses used for various optical devices and optical measuring devices, eyeglass lenses, and the like.

Further, the material of the lens is not limited to those described above, but may be a lens made of various glass materials. For example, a glass lens manufactured by a glass molding method may be used.

In the above description, the dipping method (dipping)
However, the present invention is not limited to this, and may be applied to a method of forming a coating film by, for example, spin coating, spray coating, roll coating, brush coating, or the like. Can be.

[0074]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the present invention will be described.

Example 1 FIGS. 1 to 1 manufactured by injection molding
A camera finder lens having the shape shown in FIG. 3 was prepared. This lens is 10.54mm long x 16.02mm wide,
The edge was a biconvex lens having a thickness t of 2.4 mm, and the material of the lens was polymethyl methacrylate. At the center of one long side of the lens, a gate portion having a length of about 10 mm was formed perpendicular to the long side.

A continuous groove having a rectangular cross section was formed on both sides of the edge portion (entire circumference) and the gate portion of the lens simultaneously with the molding of the lens. The dimensions of this groove are such that the width w is 0.
5 mm and depth d was 0.5 mm. This groove was formed in the edge portion at substantially the center in the lens thickness direction.

Next, the lens was immersed in a coating solution for forming a hard coat layer while the lower end of the gate portion was supported by a support (pulling-up tool) while the gate was oriented vertically downward. The conditions of the coating liquid are as follows.

Composition of coating solution: Acrylic UV-curable coating solution containing colloidal silica Viscosity of coating solution: 5.16 cps (25 ° C.) Temperature of coating solution: 20 ° C. Immersion time: 20 seconds After completion of immersion in coating solution , Lens pulling speed 190mm
Raised in the air at / min.

Next, the whole of the raised lens was irradiated with ultraviolet rays (total irradiation intensity: 85 mJ / cm ² ) to cure the applied coating liquid. As a result, a coating film (hard coat layer) was formed.

After curing of the coating, the lens was removed from the support.

Next, by a cutting device equipped with a cutting blade,
Almost all of the gate portion was cut and removed. Thus, a lens in which the first surface and the second surface were hard-coated, respectively, was completed.

The lens obtained in this manner is
The formation state of the coating film was visually observed and analyzed using a stylus-type shape evaluation device (Form Talysurf). As a result, both sides (first and second surfaces) of the lens were uniform without swelling and the like. In addition, a uniform hard coat layer was formed. The average thickness of the hard coat layer is 5.2 μm.
m.

Although a hard coat layer was also formed on the edge portion, there was no swelling of the coating film, and the average film thickness was 4.0 μm.

Example 2 The viscosity of the coating solution was 3.67 cp.
s (25 ° C.), the temperature of the coating solution was set to 20 ° C., and the pulling speed from the coating solution was set to 240 mm / min, to form a coating film (hard coat layer) in the same manner as in Example 1.

Next, the lens was removed from the support, and almost all of the gate portion was cut and removed by a cutting device. The state of coating film formation was examined in the same manner as in Example 1. On the first and second surfaces), a uniform and uniform hard coat layer without swelling was formed. The average thickness of this hard coat layer was 2.7 μm.

Although the hard coat layer was also formed on the edge portion, there was no swelling of the coating film, and the average film thickness was 1.3 μm.

Example 3 The viscosity of the coating solution was 3.67 cp.
s (25 ° C.), the temperature of the coating solution was set to 20 ° C., and the pulling speed from the coating solution was set to 320 mm / min, to form a coating film (hard coat layer) in the same manner as in Example 1.

Next, the lens was removed from the support, and almost all of the gate portion was cut and removed by a cutting device. The state of coating film formation was examined in the same manner as in Example 1. On the first and second surfaces), a uniform and uniform hard coat layer without swelling was formed. The average thickness of this hard coat layer was 3.5 μm.

Although a hard coat layer was also formed on the edge portion, there was no swelling of the coating film, and the average film thickness was 2.8 μm.

(Embodiment 4) The width w of the groove is 0.3 mm and the depth d
A coating film (hard coat layer) was formed in the same manner as in Example 1 except that a lens having a thickness of 0.4 mm was used.

Next, the lens was removed from the support, and almost all of the gate portion was cut and removed by a cutting device. The state of coating film formation was examined in the same manner as in Example 1. On the first and second surfaces), a uniform and uniform hard coat layer without swelling was formed. The average thickness of this hard coat layer was 5.2 μm.

Although the hard coat layer was also formed on the edge portion, there was no swelling of the coating film and the average film thickness was 4.7 μm.

Example 5 A coating film (hardware) was prepared in the same manner as in Example 1 except that a lens having a width w of 0.3 mm and a depth d of 0.3 mm and two grooves formed in parallel was used. (Coat layer).

Next, the lens was removed from the support, almost all of the gate portion was cut and removed by a cutting device, and the state of coating film formation was examined in the same manner as in Example 1. On the first and second surfaces), a uniform and uniform hard coat layer without swelling was formed. The average thickness of this hard coat layer was 5.2 μm.

A hard coat layer was also formed on the edge, but there was no swelling of the coating film, and the average film thickness was 4.1 μm.

[0096]

As described above, according to the present invention, a uniform coating film, particularly, a coating film having a uniform thickness can be formed at a necessary portion of an optical element. Therefore, it is possible to prevent the optical characteristics from being changed (inhibited) by the thickness unevenness of the coating film.

Further, the coating liquid can escape through the groove, so that the swelling of the coating film is prevented from being formed at the edge of the optical element, particularly at the edge of the lens. Thereby, it is possible to properly and reliably mount the lens on the supporting portion or the mounting portion such as the lens holder. When a groove is also formed in the gate portion, this effect is more remarkably exhibited.

In the present invention, the lens manufacturing process,
A uniform coating film can be easily formed without increasing the number of work steps for forming the coating film.

[Brief description of the drawings]

FIG. 1 is a front view showing an embodiment of an optical element (lens) of the present invention.

FIG. 2 is a side view showing an embodiment of the optical element (lens) of the present invention.

FIG. 3 is a bottom view showing an embodiment of the optical element (lens) of the present invention.

FIG. 4 is a front view showing an embodiment (at the time of immersing a lens in a coating solution) of the method for forming a coating film of the present invention.

FIG. 5 is a front view showing an example of the method for forming a coating film of the present invention (when the lens is pulled up from the coating liquid).

FIG. 6 is a sectional side view showing a state of a lens after a coating film is formed.

FIG. 7 is a sectional side view showing a shape of a coating film after a gate portion is removed from a lens.

FIG. 8 is a front view showing a conventional method for forming a coating film.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 lens 2 edge part 3 1st surface 4 2nd surface 5 gate part 51 cutting line 6 groove 7 support tool 8 coating liquid 80 coating liquid 9 coating film 91 swelling 10 lens 11 edge portion 12 support tool 13 swelling of coating film 14 coating Membrane swell

Continued on the front page F term (reference) 2K009 AA02 AA15 BB14 CC24 DD02 DD05 EE00 FF00 4D075 AB01 AB36 AB54 AB56 CA02 CA48 DA08 DA23 DB37 DB43 DB48 DC24 EA05 EB22 4F213 AA43 AA44 AB17 AH74 WA58 WA87 WF24

Claims (16)

[Claims] 1. An optical element used by forming a coating film on a surface thereof, wherein a groove serving as a flow path of a coating liquid when forming the coating film is formed at an edge of the optical element. An optical element, characterized in that: 2. The optical element according to claim 1, wherein the groove is formed over substantially the entire periphery of an edge of the optical element. 3. The optical element according to claim 1, wherein the optical element is a lens, and the groove is formed in an edge portion of the lens. 4. The apparatus according to claim 1, wherein when the width of the groove is w and the depth of the groove is d, w = 0.1 to 1.0 mm and d = 0.1 to 1.5 mm. An optical element according to any one of the above. 5. The optical element according to claim 1, wherein the optical element is a plastic molded product. 6. The optical element according to claim 5, wherein the groove is formed at the same time when the optical element is molded. 7. The optical element according to claim 5, further comprising a gate formed at the time of molding. 8. The optical element according to claim 7, wherein said groove is also formed in said gate portion. 9. A method for forming a coating film on an optical element according to claim 7 or 8, wherein the coating film is formed while supporting the gate portion with a support. A method for forming a coating film. 10. The method for forming a coating film for forming a coating film on an optical element according to claim 7, wherein the coating is formed while supporting the gate portion with a support. A method for forming a coating film, which comprises removing all or part of a part. 11. The method according to claim 9, wherein the formation of the coating film is performed by a dipping method. 12. The method for forming a coating film according to claim 11, wherein the pulling up of the optical element from the coating liquid is performed with the gate portion being directed downward. 13. The method for forming a coating film according to claim 11, wherein the speed of lifting the object from the coating solution is 10 to 1000 mm / min. 14. The method according to claim 9, wherein the coating is a hard coat layer. 15. The coating solution has a viscosity of 1 to 1000 cp.
The method for forming a coating film according to claim 9, wherein the temperature is s (25 ° C.). 16. The method according to claim 9, wherein the temperature of the coating solution is 5 to 40 ° C.