JP2006035780A - Mold manufacturing method, mold, lens substrate, transmission type screen and rear type projector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mold manufacturing method capable of easily corresponding even to the production of a lens substrate having a size of every kind at a low cost, a mold formed thereby, the lens substrate manufactured using the mold, a transmission type screen and a rear type projector. <P>SOLUTION: In the manufacturing method of the mold used for forming the lens substrate, the mold is obtained by combining a plurality of unit substrates having a shape corresponding to the surface shape of the lens substrate on its surface and a predetermined size. Each of the unit substrates is constituted of a metal material and a plurality of the unit substrates are spread all over the base substrate to be joined to the base substrate through a joining layer. The joining layer is mainly constituted of a metal material having a low melting point and surface roughing treatment is applied to the vicinity of the region where the unit substrates come into contact with each other on the surface of the base substrate. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a mold manufacturing method, a mold, a lens substrate, a transmissive screen, and a rear projector.

In recent years, the demand for rear-type projectors is increasing as a display suitable for home theater monitors, large-screen televisions, and the like.
A transmissive screen used for a rear projector uses a lens substrate such as a microlens substrate or a lenticular lens substrate.
As a method of manufacturing such a lens substrate, a method of manufacturing a lens substrate having a small size and connecting them together is known (for example, see Patent Document 1).

  However, the lens substrate manufactured by such a method has a problem that the joint of the lens substrate appears as a streak in the projected image. Further, since the lens substrate is bonded, there is a problem that sufficient rigidity cannot be obtained when the lens substrate is relatively large. It is also possible to manufacture a lens substrate of a desired size without joining small lens substrates by enlarging the mold, but when trying to make a relatively large lens substrate, the mold becomes larger and the lens There is a problem that not only the equipment for manufacturing the substrate is enlarged, but also the equipment for making the mold is enlarged and the cost is increased.

JP-A-5-216124

  An object of the present invention is to provide a manufacturing method of a molding die that can be easily applied to manufacture of lens substrates of various sizes at low cost, a molding die formed by the method, and manufacturing using the molding die. Another object of the present invention is to provide a lens substrate, a transmissive screen, and a rear projector.

Such an object is achieved by the present invention described below.
The method for producing a mold according to the present invention is a method for producing a mold used for forming a lens substrate,
A molding die is obtained by combining a plurality of unit substrates of a predetermined size having a shape corresponding to the surface shape of the lens substrate on the surface.

  Thereby, a seamless lens substrate can be easily manufactured, and as a result, various problems such as a seam and insufficient rigidity in the conventional lens substrate can be solved. In addition, since the size of the mold can be adjusted by adjusting the number of unit substrates to be combined, there is no need to renew the equipment for manufacturing the mold, and there are no molds that can be used for lens substrates of various sizes. Can be provided.

In the manufacturing method of the shaping | molding die of this invention, it is preferable that the said unit substrate is comprised with the metal material.
Thereby, the workability and handleability of the mold become better.
In the mold manufacturing method of the present invention, it is preferable that a plurality of the unit substrates are spread on a base substrate and bonded to the base substrate.
Thereby, the shift | offset | difference of a unit board | substrate can be prevented reliably. Further, the unit substrates can be brought into contact with each other more reliably. As a result, it is possible to more effectively prevent the seam of the unit substrate from being transferred to the obtained lens substrate.

In the mold manufacturing method of the present invention, it is preferable that the plurality of unit substrates are bonded to the base substrate via a bonding layer.
Thereby, it is possible to reliably prevent the unit substrate from shifting with time. Unit substrates can be brought into contact with each other more reliably.
In the manufacturing method of the shaping | molding die of this invention, it is preferable that the said joining layer is mainly comprised with the low melting metal material.
Thereby, a unit substrate and a base substrate can be joined more reliably. In particular, if both the unit substrate and the base substrate are made of a metal material, the unit substrate and the base substrate can be bonded more firmly, and unintentional displacement and peeling of the unit substrate can be reliably prevented. it can.

In the manufacturing method of the shaping | molding die of this invention, it is preferable that the said joining layer is mainly comprised with a heat resistant adhesive and / or a heat resistant adhesive.
Thereby, when manufacturing a lens substrate, it can prevent more reliably that a unit substrate shifts | deviates with a heat | fever. Moreover, since a unit substrate can be peeled off when an adhesive or an adhesive is used, the mold can be reassembled again according to the size of the lens substrate to be formed.

In the manufacturing method of the shaping | molding die of this invention, it is preferable to perform a roughening process with respect to the vicinity of the site | part where the said unit substrates are contacting each other on the surface of the said unit substrate.
As a result, the joints between the unit substrates can be made less noticeable. As a result, it is possible to more effectively prevent the seam of the unit substrate from being transferred to the obtained lens substrate.

In the manufacturing method of the shaping | molding die of this invention, it is preferable to perform the said roughening process by wet blasting.
Thereby, a more uniform roughening process can be performed with respect to a process surface. As a result, the joint between the unit substrates can be surely inconspicuous.
In the manufacturing method of the shaping | molding die of this invention, it is preferable that the average roughness Rz of the vicinity of the site | part where the said unit substrates are contacting is the surface of the said unit substrate is 2-3 micrometers.
As a result, the joint between the unit substrates can be surely inconspicuous.

In the method for manufacturing a mold according to the present invention, it is preferable that mirror processing is performed on a surface of the base substrate on a side where the unit substrate is bonded and / or a surface of the unit substrate on a side where the base substrate is bonded. .
Thereby, it can prevent more effectively that the joint of a unit board | substrate is transcribe | transferred to the lens board | substrate obtained.

In the manufacturing method of the shaping | molding die of this invention, it is preferable that the thickness of the said unit substrate is 100 micrometers or more.
Thereby, the handleability of the unit substrate is improved, and the mold can be formed more easily.
The mold according to the present invention is manufactured by the method according to the present invention.
As a result, a seamless lens substrate can be easily manufactured, and as a result, various problems such as joints and insufficient rigidity in the conventional lens substrate can be solved. In addition, since the size of the mold can be adjusted by adjusting the number of unit substrates to be combined, there is no need to renew the equipment for manufacturing the mold, and there are no molds that can be used for lens substrates of various sizes. Can be provided.

The lens substrate of the present invention is manufactured using the mold of the present invention.
Thereby, even a large lens substrate can be provided easily and inexpensively.
The transmission screen of the present invention is characterized by including the lens substrate of the present invention.
Thereby, even a large transmission screen can be provided easily and inexpensively.
A rear projector according to the present invention includes the transmission screen according to the present invention.
Thereby, a rear projector can be provided easily and inexpensively.

DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of a method for manufacturing a mold, a mold, a lens substrate, a transmissive screen, and a rear projector according to the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a view of the mold of the present invention as viewed from above, FIG. 2 is a view of the mold of the present invention as viewed from the side, and FIG. 3 is a vertical cross-sectional view schematically illustrating the method for producing the mold of the present invention. FIG. In the following description, in FIG. 3, the upper side is referred to as “upper” or “upper”, and the lower side is referred to as “lower” or “lower”. Moreover, in the following description, the case where it applies to a microlens substrate as a lens substrate is demonstrated. In the following description, the shape of the unit substrate surface in FIGS. 2 and 3 is omitted for easy understanding.

As shown in FIG. 1, the mold 1 has a shape corresponding to the surface shape of the lens substrate to be formed, that is, a combination of 16 unit substrates 2 of a predetermined size having a plurality of recesses 21 formed on the surface. Have a structure.
By the way, in manufacturing a conventional lens substrate, a relatively small lens substrate is manufactured, and these are joined together to manufacture a lens substrate of a desired size.

  However, in the lens substrate in which relatively small lens substrates are connected as described above, there is a problem that the joint of the lens substrate appears as a streak in the projected image. Further, since the lens substrate is bonded, there is a problem that sufficient rigidity cannot be obtained when the lens substrate is relatively large. It is also possible to manufacture a lens substrate of a desired size without joining small lens substrates by enlarging the mold, but if you try to make a relatively large lens substrate, the mold becomes larger and the lens There is a problem that not only the equipment for manufacturing the substrate is enlarged, but also the equipment for making the mold is enlarged and the cost is increased.

Therefore, as a result of intensive studies, the present inventor has formed a mold by combining a plurality of unit substrates of a predetermined size having a shape corresponding to the surface shape of the lens substrate on the surface, thereby forming a seamless lens substrate. As a result, it has been found that various problems such as seams and insufficient rigidity in the conventional lens substrate can be solved. In addition, since the size of the mold can be adjusted by adjusting the number of unit substrates to be combined, there is no need to renew the equipment for manufacturing the mold, and there are no molds that can be used for lens substrates of various sizes. Found that can be provided.
The material constituting such a unit substrate 2 is not particularly limited, and examples thereof include a metal material, glass, and a resin material. Especially, when a metal material is used, the workability and handleability of the mold 1 are better.

  The thickness of the unit substrate 2 is not particularly limited, but is preferably 100 μm or more, and more preferably 100 to 300 μm. If the thickness of the unit substrate 2 is less than the lower limit, depending on the material constituting the unit substrate 2, sufficient rigidity may not be obtained, causing difficulty in combining the unit substrates 2, and the shape of the surface. When transferring the shape, it may be difficult to transfer the shape sufficiently.

The absolute value of the difference in thickness between the plurality of unit substrates 2 is preferably 5 μm or less. Thereby, it can prevent more effectively that the joint of the unit board | substrate 2 is transcribe | transferred to the lens board | substrate obtained.
The method for forming the surface shape of the unit substrate 2 varies depending on the material constituting the unit substrate 2, and examples thereof include an electroplating method (nickel electroforming) and an etching method. Among the above, it is preferable to use an electroplating method. Thereby, the thickness of the unit substrate 2 can be easily controlled.

  When the lens substrate to be formed is relatively large and a large number of unit substrates 2 to be prepared are required, a shape corresponding to the surface shape of the lens substrate to be formed is formed on a substrate larger than the unit substrate 2 to be prepared, A plurality of unit substrates 2 may be cut out from this substrate. By doing in this way, not only can the time corresponding to the surface shape of the lens substrate be formed on each of the unit substrates 2 but also the cost can be reduced.

  As shown in FIG. 2, the mold 1 has a base substrate 3, and has a configuration in which four unit substrates 2 are spread on the base substrate 3 and bonded to the base substrate 3. By adopting such a configuration, the displacement of the unit substrate 2 can be reliably prevented. Further, the unit substrates 2 can be brought into contact with each other more reliably. As a result, it is possible to more effectively prevent the joint of the unit substrate 2 from being transferred to the obtained lens substrate.

The material constituting the base substrate 3 is not particularly limited, and examples thereof include metal materials, glass, and resin materials. Especially, when a metal material is used, the workability and handleability of the mold 1 are better.
The unit substrate 2 is bonded to the base substrate 3 via the bonding layer 4. Thereby, it is possible to reliably prevent the unit substrate 2 from shifting with time. Further, the unit substrates 2 can be brought into contact with each other more reliably.

Such a bonding layer 4 may be made of any material as long as the unit substrate 2 and the base substrate 3 are bonded to each other. As such a material, for example, a low melting point metal material, a pressure-sensitive adhesive, an adhesive, or the like may be used.
When a low melting point metal material is used as the material constituting the bonding layer 4, the unit substrate 2 and the base substrate 3 can be bonded more reliably. In particular, if both the unit substrate 2 and the base substrate 3 are made of a metal material, the unit substrate 2 and the base substrate 3 can be bonded more firmly, and unintentional displacement and peeling of the unit substrate can be ensured. Can be prevented.
Examples of the low melting point metal material include Sn, Ag, Cu, Bi, In, Zn, and alloys containing these.

Any one can be used as the pressure-sensitive adhesive and the adhesive, but it is particularly preferable to use one having heat resistance. Thereby, when manufacturing a lens substrate, it can prevent more reliably that the unit substrate 2 shifts | deviates with a heat | fever. Moreover, since the unit substrate 2 can be peeled off when an adhesive or an adhesive is used, the mold 1 can be reassembled again according to the size of the lens substrate to be formed.
Moreover, as a form of an adhesive and an adhesive agent, tape form may be sufficient and liquid may be sufficient. The tape-shaped one has the advantage of being easy to handle.

Next, a method for manufacturing the mold 1 will be described.
In the following description, a case where a low melting point metal material is used as the material constituting the bonding layer will be described.
First, as shown in FIG. 3A, a base substrate 3 is prepared. In addition, it is preferable that the surface of the base substrate 3 on the side to which the unit substrate 2 is bonded is previously subjected to mirror finishing. Thereby, it can prevent more effectively that the joint of the unit board | substrate 2 is transcribe | transferred to the lens board | substrate obtained.

Next, the base substrate 3 is heated, and in the heated state, as shown in FIG. 3B, a low melting point metal material 4 ′ liquefied by heating is supplied.
Next, 16 unit substrates 2 are prepared. In addition, it is preferable that the surface of the unit substrate 2 on the side to be joined with the base substrate 3 is previously subjected to a mirror surface treatment. Thereby, it can prevent more effectively that the joint of the unit board | substrate 2 is transcribe | transferred to the lens board | substrate obtained.

Next, as shown in FIG. 3C, the unit substrate 2 is placed and pressed on the base substrate 3 supplied with the low melting point metal material 4 ′.
Thereafter, by cooling, the low melting point metal material 4 ′ is solidified to form the bonding layer 4.
Thereby, the shaping | molding die 1 (molding die of this invention) as shown in FIG. 1, FIG. 2 is obtained.
The molding die 1 thus obtained may be subjected to various treatments as necessary.

For example, the roughening process may be performed on the vicinity of the portion where the unit substrates 2 are in contact with each other on the surface of the bonded unit substrate 2. By performing such a process, the joint between the unit substrates 2 can be made less conspicuous. As a result, it is possible to more effectively prevent the seam of the unit substrate 2 from being transferred to the obtained lens substrate.
The surface roughening treatment is not particularly limited, and examples thereof include blast treatment such as air blast, wet blast, and sand blast. In particular, when the roughening process is performed by wet blasting, a more uniform roughening process can be performed on the processing surface. As a result, the joints between the unit substrates 2 can be surely inconspicuous.

The average roughness Rz of the surface subjected to such roughening treatment is preferably about 2 to 3 μm. As a result, the joints between the unit substrates 2 can be surely inconspicuous.
In the above-described embodiment, the case where a low-melting-point metal material is used as the material used for the bonding layer has been described. However, the present invention is not limited to this, and an adhesive or an adhesive may be used.

[Production of lens substrate (molding method)]
Next, a method for manufacturing a lens substrate using the mold of the present invention will be described. In the following description, a case where the present invention is applied to manufacture of a microlens substrate will be described.
FIG. 4 is a diagram for explaining a method of manufacturing a lens substrate. In FIG. 4, the upper side is referred to as “upper part” and the lower side is referred to as “lower part”.

First, as shown in FIG.4 (d), the shaping | molding die 1 is prepared.
Next, the mold 1 is installed so that the concave portion 21 opens vertically upward, for example.
Next, uncured resin 71 (uncured raw material) that forms the resin layer 711 is supplied to the surface on which the recess 21 is formed.
A light diffusing agent may be added to the uncured resin. Examples of the diffusing agent include glass beads, silica, inorganic oxides, inorganic carbonates, inorganic sulfates, and organic resin beads.

Next, as shown in FIG. 4E, a transparent substrate 72 is joined to the resin 71 and pressed and adhered.
Next, the resin 71 is cured. This curing method is appropriately selected depending on the type of resin, and examples thereof include ultraviolet irradiation, heating, and electron beam irradiation.
Thereby, the resin layer 711 is formed, and the microlens 8 is formed by the resin filled in the recess 21.

Next, the mold 1 is peeled from the microlens 8.
Thereafter, if necessary, the thickness of the transparent substrate 72 may be adjusted by grinding, polishing, or the like.
As described above, a microlens substrate 7 (lens substrate of the present invention) as shown in FIG. 4F is obtained.
In the above-described embodiment, the case of manufacturing a microlens substrate has been described. However, the present invention can also be applied to manufacture of a lenticular lens substrate or a Fresnel lens substrate, for example.

Next, a transmission type screen using the microlens substrate 7 shown in FIG. 4F will be described with reference to FIGS. 6 is a longitudinal sectional view schematically showing the optical system of the transmission screen of the present invention, and FIG. 6 is an exploded perspective view of the transmission screen shown in FIG.
This transmissive screen 200 includes a Fresnel lens substrate 210 having a Fresnel lens formed on the exit surface side surface, and a microlens substrate 7 disposed on the exit surface side of the Fresnel lens substrate 210 and the entrance surface side surface.

A rear projector using the transmission screen will be described below.
FIG. 7 is a diagram schematically showing the configuration of the rear projector of the present invention.
As shown in the figure, the rear projector 300 has a configuration in which a projection optical unit 310, a light guide mirror 320, and a transmission screen 330 are arranged in a housing 340.
The rear projector 300 uses the transmission screen 330 having the above-described microlens substrate 7 as the transmission screen 330.

The method for manufacturing a mold, the mold, the lens substrate, the transmissive screen, and the rear projector of the present invention have been described based on the illustrated embodiments, but the present invention is not limited to these.
For example, in the above description, the mold for the microlens substrate is described as an example of the mold of the present invention, but the present invention is not limited to this. For example, the present invention can be applied to a mold for manufacturing a lenticular lens substrate, a Fresnel lens substrate, or the like.

In the above-described embodiment, the mold is manufactured using unit substrates of the same size. However, the present invention is not limited to this. For example, the unit substrates of different sizes may be combined and manufactured. .
Further, in the molding method of the present invention, an optional process can be added as necessary.
The transmission screen of the present invention may be a transmission screen further adopting a black matrix, a black stripe, a light diffusing plate, another microlens, or the like on the emission surface side or the incident surface side of the microlens substrate. .

In the above description, the case where the lens substrate of the present invention is used in a transmissive screen and a projection display device provided with the transmissive screen has been described as an example. However, the present invention is limited to this. Instead of the lens substrate of the present invention, for example, various electro-optical devices such as CCDs and optical communication elements, liquid crystal display devices (liquid crystal panels), organic or inorganic EL (Electroluminescence) display devices, other devices, etc. Needless to say, it can be used for this.
Further, the display device is not limited to the rear projection type display device. For example, the lens substrate of the present invention can be used for a front projection type display device.

It is the figure which looked at the shaping | molding die of this invention from upper direction. It is the figure which looked at the shaping | molding die of this invention from the side. It is a longitudinal cross-sectional view which shows typically the manufacturing method of the shaping | molding die of this invention. It is a figure for demonstrating the manufacturing method of a lens board | substrate. It is a longitudinal cross-sectional view which shows typically the optical system of the transmission type screen of this invention. FIG. 6 is an exploded perspective view of the transmission screen shown in FIG. 5. It is a figure which shows typically the structure of the rear type projector of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Mold 2 ... Unit substrate 21 ... Recess 3 ... Base substrate 4 ... Bonding layer 4 '... Low melting point metal material 5 ... Master master 7 ... Micro lens substrate 71 ... Resin 711 ... Resin layer 72 …… Transparent substrate 8 …… Micro lens 200 …… Transmissive screen 210 …… Fresnel lens substrate 300 …… Rear projector 310 …… Projection optical unit 320 …… Light guide mirror 330 …… Transmissive screen 340… ... Case

Claims (15)

A method of manufacturing a mold used for forming a lens substrate,
A method for producing a mold, comprising: obtaining a mold by combining a plurality of unit substrates of a predetermined size having a shape corresponding to the surface shape of the lens substrate on the surface.   The manufacturing method of the shaping | molding die of Claim 1 with which the said unit substrate is comprised with the metal material.   The manufacturing method of the shaping | molding die of Claim 1 or 2 which spreads the said several unit substrate on a base substrate, and joins to the said base substrate.   The method for manufacturing a mold according to claim 3, wherein the plurality of unit substrates are bonded to the base substrate via a bonding layer.   The said joining layer is a manufacturing method of the shaping | molding die of Claim 3 comprised mainly with a low melting-point metal material.   The said joining layer is a manufacturing method of the shaping | molding die of Claim 5 comprised mainly with a heat resistant adhesive and / or a heat resistant adhesive agent.   The manufacturing method of the shaping | molding die in any one of Claim 1 thru | or 6 which performs the roughening process with respect to the vicinity of the site | part where the said unit substrates are contacting each other on the surface of the said unit substrate.   The method for manufacturing a mold according to claim 7, wherein the roughening treatment is performed by wet blasting.   The method for manufacturing a mold according to claim 7 or 8, wherein an average roughness Rz in the vicinity of a portion where the unit substrates are in contact with each other on the surface of the unit substrate is 2 to 3 µm.   The mold according to any one of claims 3 to 9, wherein mirror processing is performed on a surface of the base substrate on which the unit substrate is bonded and / or on a surface of the unit substrate on which the base substrate is bonded. Manufacturing method.   The method for manufacturing a molding die according to claim 1, wherein the unit substrate has a thickness of 100 μm or more.   A molding die produced by the method according to claim 1.   A lens substrate manufactured using the mold according to claim 12.   A transmissive screen comprising the lens substrate according to claim 13. A rear projector comprising the transmission screen according to claim 14.

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