JP2002296418A - Phase contrast plate and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a phase contrast plate using a phase contrast film which is more inexpensive than have to fore. SOLUTION: The phase contrast plate 10 has an annular frame 11 having a principal plane 11a with an opening 111 in the center and has a phase difference film 15 stuck to the principal plane of the annular frame. Or, another phase contrast plate has a pair of annular frames each having the principal plane and an opening in the center and has a phase contrast film interposed between the principal faces of the pair of annular frames. The annular frame may be made of, for example, a metal or an injection molded product.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to an optical component,
In particular, the present invention relates to a retardation plate such as a half-wave plate or a quarter-wave plate used as an optical component of an optical pickup that employs a polarizing optical system and is built in an optical disk device.

[0002]

2. Description of the Related Art As is well known, an optical pickup built in an optical disk apparatus collects laser light emitted (irradiated) from a semiconductor laser (laser diode) as a light source on a signal recording surface of an optical disk by an objective lens. Recording (writing) or erasing of information is performed by illuminating the light, and information is reproduced by detecting a disk reflected light (return light) from the signal recording surface with a photodetector as a light detecting means. Device.

As such an optical pickup, there has been known an optical pickup employing a polarization optical system as an optical system. Here, the “polarization optical system” refers to an optical system that can change the polarization direction of laser light. An optical pickup employing a polarization optical system requires an optical component that changes the polarization direction of laser light. A retardation plate such as a half-wave plate or a quarter-wave plate is generally used as such an optical component.

Conventionally, a quartz substrate has generally been used as a phase difference plate. However, since the quartz substrate is expensive, an inexpensive retardation plate has been demanded.

In response to this demand, recently,
It is becoming mainstream to use a material obtained by laminating a retardation film on a transparent base material such as glass as a retardation plate.

FIGS. 5 and 6 show a retardation plate using a conventional retardation film. FIG. 5 shows a first conventional retarder 10 ', and FIG. 6 shows a second conventional retarder 10 ".

As shown in FIG. 5, a first conventional phase difference plate 10 'has a rectangular parallelepiped main surface 1 as a transparent base material.
It has a glass 11 'having 1'a and a retardation film 15 adhered to the main surface 11'a of the glass 11'.

On the other hand, a second conventional retardation plate 10 "has a pair of rectangular parallelepiped glasses 11" and 12 "each having main surfaces 11" a and 12 "a, and a pair of the glasses 11" and 11 ". And a retardation plate 15 sandwiched between the 12 "principal surfaces 11" a and 12 "a.

[0009]

However, as shown in FIGS. 5 and 6, the phase difference plates 10 ', 10 "
In a conventional manufacturing method in which a retardation film is bonded to a transparent base material such as glass, the cost is reduced because the base materials such as glass 11 ′, 11 ″, and 12 ″ are expensive. It is difficult to plan. In particular, the principal surfaces 11'a, 11 "a, and 12" a of the transparent base material to which the retardation film 15 is to be bonded are required to have as precise a flatness as possible. Transparent preforms with such precise flat major surfaces are themselves expensive. If an inexpensive transparent base material is used, its main surface must be precisely polished, resulting in an expensive one.

Therefore, a retardation plate using a retardation film without using glass or the like as a transparent base material is desired.

It is therefore an object of the present invention to provide a retardation plate using a retardation film, which is less expensive than conventional ones.

Another object of the present invention is to provide a method of manufacturing a retardation plate which can be manufactured at a lower cost than a conventional manufacturing method.

[0013]

According to a first aspect of the present invention, there is provided an annular frame (11) having an opening (111) in the center and having a main surface (11a); A retardation plate (10) having the retardation film (15) attached to the main surface is obtained. In this retardation plate, the annular frame may be made of, for example, metal or an injection-molded product.

According to the second aspect of the present invention, the main surfaces (11a, 12a) each having an opening (111, 121) at the center.
a) and a retardation film (1) sandwiched between the main surfaces of the pair of annular frames.
5) is obtained. In this retardation plate, each of the pair of annular frames may be made of, for example, metal or an injection-molded product.

In the above retardation plate, for example, a polarizing film can be used as the retardation film.

According to the present invention, a plurality of grid units (11) arranged in a grid pattern at regular intervals in the vertical and horizontal directions.
A hole (111) is formed in the center of each of the main surfaces (1).
1a) preparing a lattice plate (20), attaching a retardation film (15) to the main surface of the lattice plate, and attaching the retardation film to the lattice plate. And a step of cutting for each unit (11).

In the method for manufacturing a phase difference plate according to the first aspect of the present invention, a step of preparing a metal flat plate having a main surface, and arranging the metal flat plates in a grid pattern at regular intervals in the vertical and horizontal directions. Is divided into a plurality of lattice units (11), and a hole (111) extending in a direction orthogonal to the main surface (11a) is formed in each lattice unit to thereby form a lattice-like metal plate (2).
0), a step of attaching a retardation film (15) to the main surface of the lattice-like metal plate, and a step of attaching the lattice-like metal plate with the retardation film attached to each lattice unit (11). Cutting.

In the method for manufacturing a retardation plate according to the first aspect, the step of manufacturing the lattice-shaped metal plate may be, for example, a step of forming the lattice-shaped metal plate by punching the metal plate. Alternatively, a step of forming the lattice-shaped metal plate by wet-etching the metal plate may be employed. Further, the method may further include a step of forming an antireflection film on the retardation film after the step of attaching the retardation film and before the step of cutting for each lattice unit. Further, the step of cutting for each lattice unit may be a step of cutting the lattice-like metal to which the retardation film is attached by cutting for each lattice unit.

In the method for manufacturing a retardation plate according to the second aspect of the present invention, there is provided a step of preparing a metal flat plate having a main surface, and arranging the metal flat plates at regular intervals in a vertical direction and a horizontal direction. And a hole (111) extending in a direction perpendicular to the main surface (11a) is formed in each of the lattice units, and a gate (111) is provided between adjacent lattice units. 16) providing a grid-like metal plate (20A) provided with 16), attaching a retardation film (15) to the main surface of the lattice-like metal plate, and attaching the retardation film to the lattice. Cutting the shaped metal plate for each lattice unit (11).

In the method for manufacturing a retardation plate according to the second aspect, the step of manufacturing the lattice-like metal plate may be, for example, a step of forming the lattice-like metal plate by punching the metal plate. Alternatively, a step of forming the lattice-shaped metal plate by wet-etching the metal plate may be employed. Further, the method may further include a step of forming an antireflection film on the retardation film after the step of attaching the retardation film and before the step of cutting for each lattice unit. Further, the step of cutting for each lattice unit may be a step of cutting the lattice-like metal to which the retardation film is attached by cutting for each lattice unit.

In the method for manufacturing a retardation plate according to a third aspect of the present invention, a plurality of grid units (11) arranged in a grid pattern at regular intervals in the vertical and horizontal directions by injection molding. A step of forming a resin lattice plate (20) having a main surface (11a) in which (111) is perforated, and attaching a retardation film (15) to the main surface of the resin lattice plate. And a step of cutting the resin lattice plate to which the retardation film is attached for each lattice unit (11).

In the method for manufacturing a retardation plate according to the third aspect, after the step of attaching the retardation film,
Before the step of cutting for each lattice unit, a step of forming an antireflection film on the retardation film may be further included.

In the method for manufacturing a retardation plate according to a fourth aspect of the present invention, a plurality of lattice units (11) arranged in a grid pattern at regular intervals in the vertical and horizontal directions by injection molding. A step of forming a resin grid plate (20A) having a main surface (11a), in which (111) is perforated and adjacent grid units are connected by a gate (16); A) attaching a retardation film (15) to the main surface, and cutting the resin lattice plate to which the retardation film is attached into lattice units (11).

In the method for manufacturing a retardation plate according to the fourth aspect, after the step of attaching the retardation film,
Before the step of cutting for each lattice unit, a step of forming an antireflection film on the retardation film may be further included.

Further, according to the present invention, a hole (111, 121) is provided at the center of each of a plurality of grid units (11, 12) arranged in a grid pattern at regular intervals in the vertical and horizontal directions.
Preparing a pair of grid-like plates (20, 20A) each having a main surface (11a, 12a), and a retardation film (15) between the main surfaces of the pair of grid-like plates. ), And a step of cutting a pair of lattice-like plates with a retardation film between them for each lattice unit (11, 12).

In the method for manufacturing a retardation plate, for example, a polarizing film can be used as the retardation film.

It should be noted that the reference numerals in the parentheses are provided for easy understanding, are merely examples, and are not intended to limit the scope of the present invention.

[0028]

Embodiments of the present invention will be described below in detail with reference to the drawings.

Referring to FIG. 1, a description will be given of a retardation plate 10 according to a first embodiment of the present invention. The illustrated retardation plate 10 has an opening 111 having a rectangular cross section in the center and has a main surface 1.
It has a rectangular annular frame 11 having 1a and a retardation film 15 attached to a main surface 11a of the annular frame 11. The annular frame 11 may be made of, for example, metal or an injection molded product.

In the retardation plate 10 having such a configuration,
The central portion of the annular frame 11 is substantially empty, and the cavity (opening) 1 is substantially the only portion used as an optical component (optical element) for the polarization optical system of the optical pickup.
Since it is 11, substantially only the central portion of the retardation film 15 functions as an optical element. Conversely, the annular frame 11 holding (supporting) the retardation film 15
Is a portion that does not act as an optical element of any optical system.

As described above, by using the annular frame 11 as a base material on which the retardation film 15 is to be adhered, no flatness accuracy is required for the main surface 11a to which the retardation film 15 is to be adhered. , Simply the retardation film 15
It is only necessary to have the function of pasting the. Further, since the annular frame 11 does not work as an optical element of the optical system, it need not be transparent. That is, as the base material to which the retardation film 15 is adhered, there is no need to use a transparent base material as in the conventionally used glass, and an inexpensive material such as a metal product or an injection molded product is used. it can.

Next, a first manufacturing method for manufacturing the retardation plate 10 shown in FIG. 1 will be described with reference to FIG.
Here, description will be made assuming that the annular frame 11 is made of metal.

First, a metal flat plate (not shown) having a main surface is prepared. As shown in FIG. 2A, the metal plate is divided into a plurality of lattice units 11 arranged in a grid pattern at regular intervals in the vertical and horizontal directions, and each lattice unit 11 has a main surface 11a. The lattice-shaped metal plate 20 is manufactured by piercing a hole (opening) 111 having a rectangular cross section extending in a direction orthogonal to the above.

The step of fabricating the lattice-shaped metal plate 20 may be a step of forming the lattice-shaped metal plate 20 by punching a metal plate, or a step of wet-etching the metal plate to form the lattice-shaped metal plate. The step of forming the plate 20 may be performed.

Subsequently, as shown in FIG.
The retardation film 15 is attached to the main surface 11a of the lattice-shaped metal plate 20. At this time, an antireflection film or the like may be formed on the retardation film 15.

Finally, as shown in FIG. 2 (C), the grid-like metal plate 20 to which the retardation film 15 is attached is cut for each lattice unit so that the retardation plate as shown in FIG. 10 is manufactured. Here, the step of cutting each lattice unit 11 is performed, for example, by cutting the lattice-like metal 20 (FIG. 2B) to which the retardation film 15 is attached by cutting.
It may be a step of cutting each time.

By adopting such a manufacturing method, the conventional retardation plate 10 '(FIG. 5) or 10 "(FIG. 6)
It is possible to provide the phase difference plate 10 at a lower cost.

Next, a second manufacturing method for manufacturing the retardation plate 10 shown in FIG. 1 will be described with reference to FIG.
Here, description will be made on the assumption that the annular frame 11 is made of metal.

In the second manufacturing method, the step of manufacturing the grid-like metal plate is the same as the first manufacturing method, except that the step is different from that shown in FIG. Therefore, the grid-like metal plate is illustrated by 20A. The other steps are the same as those in the first manufacturing method, and the description is omitted.

That is, in the step of manufacturing the grid-like metal plate 20A in the second manufacturing method, as shown in FIGS. 3A and 3B, the metal flat plate is Is divided into a plurality of lattice units 11 arranged in a grid pattern, holes 111 extending in a direction orthogonal to the main surface 11a are formed in each lattice unit 11, and a gate is provided between adjacent lattice units 11. This is the step of providing 16.

As described above, in the second manufacturing method, since the gates 16 are provided between the adjacent lattice units 11, the cutting operation, which is a subsequent step, is significantly simplified. Accordingly, it is possible to further reduce the cost compared to the first manufacturing method.

In the first and second manufacturing methods described above, an example in which the annular frame 11 is made of metal has been described. However, the annular frame 11 may be an injection molded product. In this case, only the process of manufacturing the grid plate is different.

That is, in the third manufacturing method in the case where the annular frame 11 is an injection-molded article, as shown in FIG. And a step of forming a resin lattice plate 20 having a main surface 11a, in which holes 111 are formed in a plurality of lattice units 11 arranged in a grid pattern at regular intervals in the horizontal direction.

In the fourth manufacturing method in the case where the annular frame 11 is an injection-molded product, as shown in FIGS. 3A and 3B, the step of manufacturing a grid-like plate is performed by injection molding. As a result, holes 111 are formed in each of a plurality of grid units 11 arranged in a grid pattern at regular intervals in the vertical direction and the horizontal direction, and the adjacent grid units 11 are connected by gates 16 to the main surface 11a. This is a step of molding a resin lattice plate 20A having the following.

Referring to FIG. 4, a phase difference plate 10A according to a second embodiment of the present invention will be described. The illustrated phase difference plate 10A has a pair of annular frames 11, 12 having openings 111, 121 in the center and main surfaces 11a, 12a, respectively.
And the main surfaces 11a, 12 of the pair of annular frames 11, 12
a) and a retardation film 15 interposed therebetween. Each of the pair of annular frames 11 and 12 may be made of, for example, metal or an injection molded product.

In the retardation plate 10A having such a configuration, only the central portion is used substantially as an optical component (optical element) of the polarization optical system of the optical pickup, and the pair of annular frames 11, 12 is used. Since there are no cavities (openings) 111 and 121 in the center of the phase difference film 15, substantially only the center of the retardation film 15 functions as an optical element. Conversely, holding (supporting) the retardation film 15
The pair of annular frames 11 and 12 do not function as an optical system (optical element).

As described above, by using the pair of annular frames 11 and 12 as the base material on which the retardation film 15 is adhered, the main surface 11 on which the retardation film 15 is to be adhered is formed.
a and 12a do not require any flatness accuracy,
What is necessary is just to have only the function of attaching the retardation film 15. Further, the pair of annular frames 11 and 12 do not need to be transparent because they do not work as elements of the optical system at all. That is, as the base material to which the retardation film 15 is attached, it is not necessary to use a base material having transparency such as conventionally used glass, and an inexpensive material such as a metal product or an injection molded product can be used. .

In order to manufacture the phase difference plate 10A shown in FIG. 4, two (two) lattice plates 20 or 20A shown in FIGS. 2A and 3A are prepared. good.

That is, the method of manufacturing the phase difference plate 10A is such that the holes 111, 12 are formed in a plurality of lattice units 11, 12, which are arranged in a grid pattern at regular intervals in the vertical and horizontal directions.
A step of preparing a pair of grid-like plates 20 or 20A each having a main surface 11a, 12a, and a phase difference film between the main surfaces 11a, 12a of the pair of grid-like plates 20 or 20A. 15 and the step of sandwiching the retardation film 1
Cutting the pair of grid-like plates 20 or 20A with the grid 5 interposed between the grid units 11 and 12.

The present invention is not limited to the above embodiment,
It goes without saying that various changes and modifications can be made without departing from the spirit of the present invention. For example, in the above-described embodiment, the retardation film is formed using the retardation film.
A retardation plate may be used by using a polarizing film instead of the retardation film. In addition, although the cross-sectional shape of the hole formed in the center of the annular frame is rectangular, it goes without saying that the hole may have another shape such as a circle.

[0051]

As is apparent from the above description, according to the present invention, an annular frame having an opening (hole) at the center is used as a base material to which a retardation film is to be bonded. There is no need to use a transparent base material such as glass that is used, and an inexpensive material can be used. This has the effect of providing a less expensive retarder than the conventional one.

[Brief description of the drawings]

FIG. 1 is a perspective view of a retardation plate according to a first embodiment of the present invention.

FIG. 2 is a view for explaining a first manufacturing method for manufacturing the retardation plate shown in FIG.

FIG. 3 is a view for explaining a second manufacturing method for manufacturing the retardation plate shown in FIG. 1;

FIG. 4 is a perspective view of a retardation plate according to a second embodiment of the present invention.

FIG. 5 is a perspective view showing a first conventional retardation plate.

FIG. 6 is a perspective view showing a second conventional retardation plate.

[Explanation of symbols]

 10, 10A Phase difference plate 11, 12 Annular frame (lattice unit) 11a, 12a Main surface 111, 121 Opening (hole) 16 Gate 20, 20A Lattice plate

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Katsuhito Umezu 5-105-1 Tanigawa, Yamagata City, Yamagata Prefecture Inside Yamagata Mitsumi Co., Ltd. F term in reference (reference) 2H049 BA02 BA06 BA07 BB65 BC13 BC14 BC21 5D119 AA40 JA31

Claims (24)

[Claims] 1. A retardation plate comprising: an annular frame having an opening at a central portion and having a main surface; and a retardation film attached to the main surface of the annular frame. 2. The annular frame body is made of metal.
2. The retardation plate according to 1. 3. The retardation plate according to claim 1, wherein the annular frame is an injection molded product. 4. A retardation plate comprising: a pair of annular frames each having an opening at a central portion and having a main surface; and a retardation film sandwiched between the main surfaces of the pair of annular frames. 5. The retardation plate according to claim 4, wherein each of said pair of annular frames is made of metal. 6. The retardation plate according to claim 4, wherein each of the pair of annular frames is an injection molded product. 7. A step of preparing a lattice-like plate having a main surface, in which a hole is formed in the center of each of a plurality of lattice units arranged in a grid pattern at regular intervals in the vertical and horizontal directions. A method of manufacturing a retardation plate, comprising: a step of attaching a retardation film to the main surface of the lattice plate; and a step of cutting the lattice plate to which the retardation film is attached into lattice units. 8. A step of preparing a metal flat plate having a main surface; and dividing the metal flat plate into a plurality of grid units arranged in a grid pattern at regular intervals in a vertical direction and a horizontal direction. Forming a lattice-shaped metal plate by piercing a hole extending in a direction perpendicular to the main surface, and attaching a retardation film to the main surface of the lattice-shaped metal plate; Cutting the lattice-like metal plate to which the retardation film has been attached for each lattice unit. 9. The method for manufacturing a retardation plate according to claim 8, wherein the step of producing the lattice-shaped metal plate is a step of forming the lattice-shaped metal plate by punching the metal plate. 10. The step of producing the grid-like metal plate,
The method for manufacturing a retardation plate according to claim 8, wherein the step of forming the lattice-shaped metal plate by wet-etching the flat metal plate. 11. The method according to claim 8, further comprising a step of forming an antireflection film on the retardation film after the step of attaching the retardation film and before the step of cutting for each lattice unit. A method for manufacturing the phase difference plate according to the above. 12. The retardation plate according to claim 8, wherein the step of cutting for each lattice unit is a step of cutting the lattice-like metal to which the retardation film is attached by cutting for each lattice unit. Production method. 13. A step of preparing a metal flat plate having a main surface; and dividing the metal flat plate into a plurality of grid units arranged in a grid pattern at regular intervals in a vertical direction and a horizontal direction. Forming a hole extending in a direction perpendicular to the main surface, and providing a gate between adjacent lattice units, producing a lattice-shaped metal plate; and forming a lattice-shaped metal plate on the main surface of the lattice-shaped metal plate. A method for manufacturing a retardation plate, comprising: a step of attaching a retardation film; and a step of cutting the lattice-like metal plate to which the retardation film is attached into lattice units. 14. The step of producing the lattice-like metal plate,
The method for manufacturing a retardation plate according to claim 13, wherein the method is a step of forming the lattice-shaped metal plate by punching the metal plate. 15. The step of producing the grid-like metal plate,
14. The method for manufacturing a retardation plate according to claim 13, wherein the step of forming the lattice-shaped metal plate by wet-etching the metal flat plate. 16. The method according to claim 13, further comprising a step of forming an antireflection film on the retardation film after the step of attaching the retardation film and before the step of cutting for each lattice unit. A method for manufacturing the phase difference plate according to the above. 17. The retardation plate according to claim 13, wherein the step of cutting for each lattice unit is a step of cutting the lattice-like metal to which the retardation film is adhered for each lattice unit by cutting. Production method. 18. A resin grid having a main surface, wherein holes are formed at the center of each of a plurality of grid units arranged in a grid pattern at regular intervals in the vertical and horizontal directions by injection molding. Forming a plate, attaching a retardation film to the main surface of the resin lattice plate, and cutting the resin lattice plate attached with the retardation film for each lattice unit. A method of manufacturing a retardation plate. 19. The method according to claim 18, further comprising a step of forming an antireflection film on the retardation film after the step of attaching the retardation film and before the step of cutting for each lattice unit. A method for manufacturing the phase difference plate according to the above. 20. A hole is formed at the center of each of a plurality of grid units arranged in a grid pattern at regular intervals in the vertical and horizontal directions by injection molding, and a gate is provided between adjacent grid units. A step of forming a connected resin lattice plate having a main surface; a step of attaching a retardation film to the principal surface of the resin lattice plate; and a resin lattice attached to the retardation film. Cutting the plate for each lattice unit. 21. The method according to claim 20, further comprising a step of forming an antireflection film on the retardation film after the step of attaching the retardation film and before the step of cutting for each lattice unit. A method for manufacturing the phase difference plate according to the above. 22. A pair of grid-like plates, each having a main surface, each having a hole in the center of a plurality of grid units arranged in a grid pattern at regular intervals in the vertical and horizontal directions. Preparing, including a step of interposing a retardation film between the main surfaces of the pair of lattice plates, and a step of cutting the pair of lattice plates between which the retardation film is interposed for each lattice unit A method for manufacturing a phase difference plate. 23. The retardation plate according to claim 1, wherein the phase film is a polarizing film. 24. The method of manufacturing a retardation plate according to claim 7, wherein the phase film is a polarizing film.