JPH09197110A - Production of pasted substrate having microprism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent chip and crack of a substrate having a microprism. SOLUTION: Microlenses ML are first formed on one surface 1a side of the substrate 1 for forming flat planer lenses. A substrate for a flat planar base plate is then pasted via a first resin on the one surface 1a side of the substrate 1 for forming the lenses having these microlenses ML formed. Next, the other surface side of the substrate 1 for forming the lenses is then polished to a prescribed thickness with the substrate for the base plate as a supporting member. The microprisms are formed on the other surface side subjected to polishing of the substrate 1 for forming the lenses.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a bonded substrate having a micro prism used for a counter substrate of a liquid crystal display device or the like.

[0002]

2. Description of the Related Art Conventionally, as a transmissive display device using a liquid crystal panel, in order to obtain image brightness, white light from a white lamp is used by using three dichroic mirrors (red) R, (green). G, (blue) B primary colors are separated, and these are incident on a monochrome liquid crystal panel without a color filter through a microlens, and RGB with an angle difference are provided.
A technique has been disclosed in which components are focused on corresponding pixels to obtain a desired color image (see Japanese Patent Laid-Open No. 4-60538).

Further, in a so-called color filter-less type transmissive display device which does not include such a color filter, when a high-definition liquid crystal panel having a small pixel pitch is used, the focal length of the microlens is very large. Need to be short. For this reason, it is necessary to use a projection lens with a large aperture in order to project all the light flux that has passed through the liquid crystal panel.

Therefore, in order to cope with miniaturization and high definition of a main body in a so-called color filterless type transmission display device, a substrate on which a micro-prism is formed is adhered to a substrate on which a micro-lens is formed as a counter substrate. A transmissive display device using a laminated structure has been considered.

[0005]

However, as described above, it is necessary to make the focal length of the microlens extremely short in order to cope with a high-definition liquid crystal panel having a small pixel pitch. When the substrates provided with the micro prisms are bonded together, it is necessary to thin the substrate on which the micro prisms are formed to correspond to the focal length of the micro lens.

However, when the thickness of the substrate forming the microprisms is small, chipping or cracking of the substrate is likely to occur during the manufacturing process of the microprisms or during the transportation process after the manufacturing. In addition, due to the refractive index of the substrate or the adhesive, a microlens may be formed on one side of the substrate and a microprism may be formed on the other side of the substrate. If the substrate used for this is thin, The chipping or cracking of the substrate will be prominent on the way or during the transportation process.

[0007]

The present invention is a method for manufacturing a bonded substrate having a micro-prism, which is made to solve the above problems. That is, first, a microlens is formed on one surface side of a plate-shaped lens forming substrate, and then a plate-shaped base is provided on one surface side of the lens forming substrate on which the microlens is formed with a predetermined resin interposed. Attach the substrate. Next, with the manufacturing method of polishing the other surface side of the lens forming substrate to a predetermined thickness by using the base substrate as a supporting member to form a microprism on the other surface side of the lens forming substrate that has been polished. is there.

In addition, first, a microlens is formed on one surface side of a flat base substrate, and then a flat resin is formed on one surface side of the base substrate on which the microlens is formed with a predetermined resin interposed therebetween. The lens forming substrate of is bonded. Next, using the base substrate as a supporting member, the surface side of the lens forming substrate on which the base substrate is not bonded is polished to a predetermined thickness, and the surface of the lens forming substrate that has been polished is micro-machined. It is also a manufacturing method for forming a prism.

In such a manufacturing method, when the lens-forming substrate on which at least the microprisms are formed is formed to have a predetermined thickness, polishing is performed by using the base substrate bonded with resin as a supporting member. Therefore, even when the lens forming substrate is thinned, the base substrate does not serve as a support and does not cause chipping or cracking. Further, even when the lens forming substrate is conveyed, the base substrate serves as a support, and it is possible to prevent the occurrence of chipping or cracking.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a method for manufacturing a bonded substrate having a micro prism of the present invention will be described below with reference to the drawings. 1 to 3 are schematic cross-sectional views illustrating the manufacturing method according to the first embodiment.

In the first embodiment, a counter substrate used in a liquid crystal display device is taken as an example of a bonded substrate, and a lens forming substrate 1 in which micro lenses ML and micro prisms MP are formed in the counter substrate 10,
The process is characterized in that the lens-forming substrate 1 is bonded to the base substrate 2 when it is polished to manufacture the lens-forming substrate 1.

First, the microlenses ML are formed on the one surface 1a side of the lens forming substrate 1 by the processing shown in FIGS. That is, in the process shown in FIG. 1A, the resist R1 is applied to the one surface 1a of the lens-forming substrate 1 made of quartz glass, and mask exposure, development and post-baking are performed. Then, a high selectivity etching (reaction gas: CCl ₄ ) is performed by using, for example, a parallel plate plasma etching apparatus to form a recess O as shown in FIG. 1B.

Further, in the process shown in FIG. 1B, a resist R2 is applied to the one surface 1a of the lens forming substrate 1 and mask exposure, development and post-baking are performed to perform the process shown in FIG.
The resist R2 is left only in the portion corresponding to the convex portion of the microlens ML shown in FIG.

In the next process shown in FIG. 1C, the process shown in FIG.
Using the resist R2 shown in (b) as a mask, parallel plate plasma etching (reaction gas: CCl ₄ , CF ₄ , CH
Perform the F _3, etc.). At this time, the lens forming substrate 1 is taper-etched while etching the resist R2 with oxygen. As a result, a plurality of microlenses ML as shown in FIG.
Formed.

Next, as shown in FIG. 2A, the first resin 11 made of a transparent adhesive having a predetermined refractive index is interposed on the side of the lens forming substrate 1 where the microlenses ML are formed. Then, a flat substrate substrate 2 made of, for example, quartz glass is bonded.

The first resin 11 is made of, for example, an epoxy resin or an acrylic resin, and has a refractive index smaller than that of the lens forming substrate 1. Also, the first resin 1
When 1 is applied, first, the microlens ML side is applied and embedded, and the surface is leveled and flattened. Next, degassing is performed by vacuum heating, and uniform pressure is applied at the pressure for returning to atmospheric pressure. After that, the jig is pressed and heated to cure.
Moreover, you may degas in a vacuum and heat-cure (1 atmospheric pressure or less, 200 degreeC 1 hour cure). Furthermore, when the first resin 11 of the ultraviolet irradiation curing type is used, it is defoamed in a vacuum and then irradiated with ultraviolet rays in a vacuum (for example,
3000 to 4000 mJ / cm ² ) curing.

Next, as shown in FIG. 2B, the other surface 1 of the lens-forming substrate 1 using the base substrate 2 as a supporting member.
The b side is optically polished to a predetermined thickness. For example, when the original thickness t _{0 of} the lens forming substrate 1 is 0.5 mm, the thickness t ₁ after optical polishing is set to about 0.2 mm. When optically polishing to such a thickness, the base substrate 2
Plays a role as a supporting member, so that the lens forming substrate 1 is not chipped or cracked during the optical polishing.

Next, as shown in FIG. 2C, a resist R3 is applied to the other surface 1b side of the optically polished lens forming substrate 1, and mask exposure, development and post-baking are performed. Then, high selective ratio etching (reaction gas: CCl ₄ , CF ₄ , C
HF ₃ etc.) is performed to form a concave portion O ′ on the other surface 1b side corresponding to the convex portion of the microlens ML.

Then, after removing the resist R3,
As shown in FIG. 3A, a resist R4 is applied to the other surface 1b side of the lens forming substrate 1, mask exposure, development and post-baking are performed, and only a portion corresponding to a boundary between the plurality of microlenses ML is formed. Try to leave. At this time, the resist R4 is left on at least the bottom surface of the recess O '. In this state, parallel plate plasma etching is performed (reaction gas: CCl ₄ , O ₂ , CF ₄ , CHF ₃
Etc.), the other surface 1b side of the lens forming substrate 1 is taper-etched while etching the resist R4 with oxygen.

As a result, as shown in FIG.
A plurality of micro prisms MP as shown in (b) are formed on the lens forming substrate 1. After that, the transparent electrode 3 is formed on the micro prism MP via the second resin 12 made of a transparent adhesive having a predetermined refractive index. The second resin 12 is made of, for example, an epoxy resin or an acrylic resin, and has a refractive index larger than that of the lens forming substrate 1.

When applying the second resin 12, first,
The concave portion of the micro prism MP is coated and embedded, and the surface is leveled to be flat. Next, degassing is performed by vacuum heating, and uniform pressure is applied at the pressure for returning to atmospheric pressure. afterwards,
Harden by heating with a jig. Moreover, you may degas in a vacuum and heat-cure (1 atmospheric pressure or less, 200 degreeC 1 hour cure). Furthermore, when the second resin 12 of the ultraviolet irradiation curing type is used, it is defoamed in a vacuum and then irradiated with ultraviolet rays in a vacuum (for example, 3000 to 4000).
mJ / cm ² ) cure.

As the transparent electrode 3, for example, ITO is used.
And IXO are formed to a thickness of about 140 nm by sputtering. As a result, the counter substrate 10 is completed.

In the first embodiment described above, the refractive index of the lens forming substrate 1 is larger than that of the first resin 11, and the refractive index of the second resin 12 is larger than that of the lens forming substrate 1. Since the larger material is used, the convex microlenses ML and the concave microprisms MP are formed on the lens forming substrate 1, but various modes can be considered depending on the combination of the respective refractive indexes.

FIG. 4 is a schematic sectional view for explaining another example of the first embodiment. That is, in the counter substrate 10 shown in FIG. 4A, the lens forming substrate 1 has a larger refractive index than the first resin 11 and the lens forming substrate 1 has a larger refractive index than the second resin 12. Has a higher refractive index. In such a case, the microlenses ML and the microprisms MP may be formed in a convex shape on the lens forming substrate 1.

In the counter substrate 10 shown in FIG. 4B, the refractive index of the lens forming substrate 1 is smaller than the refractive index of the first resin 11, and the second refractive index of the lens forming substrate 1 is smaller than that of the lens forming substrate 1. The refractive index of the resin 12 is smaller. In such a case, the microlens ML may be formed in a concave shape and the microprism MP may be formed in a convex shape on the lens forming substrate 1.

Further, in the counter substrate 10 shown in FIG. 4C, the refractive index of the lens forming substrate 1 is smaller than that of the first resin 11, and the second resin is smaller than that of the lens forming substrate 1. The refractive index of 12 is smaller. In such a case, the microlens M is formed on the lens forming substrate 1.
Both L and the micro prism MP may be formed in a concave shape.

Next, a method of manufacturing the bonded substrate stack according to the second embodiment of the present invention will be described. 5 to 6 are schematic cross-sectional views illustrating the manufacturing method according to the second embodiment.
In the second embodiment, as in the first embodiment, the opposite substrate used in the liquid crystal display device is taken as an example of the bonded substrate, but the microlens ML is formed on the base substrate 2,
The difference is that the micro prism MP is formed on the lens forming substrate 1.

First, by the process shown in FIG. 5A, a plurality of microlenses ML are formed on the base substrate 2 made of, for example, quartz glass. The method of forming the microlens ML is the same as that of the first embodiment shown in FIGS.

Next, as shown in FIG. 5B, the first resin 11 made of a transparent adhesive having a predetermined refractive index is interposed on the side of the base substrate 2 on which the microlenses ML are formed. Then, the flat plate-shaped lens forming substrate 1 is attached. First
The resin 11 is made of, for example, an epoxy resin or an acrylic resin and has a refractive index smaller than that of the base substrate 2 as in the first embodiment. Moreover, as the lens forming substrate 1, for example, quartz glass is used. In addition,
As for the method of applying the first resin 11, as in the first embodiment, defoaming is performed in a vacuum so that no air bubbles remain, and heating or ultraviolet irradiation curing is performed.

Next, as shown in FIG. 5C, the one surface 1a of the bonded lens forming substrate 1 is optically polished to a predetermined thickness using the base substrate 2 as a supporting member.
For example, the original thickness t _{0 of} the lens forming substrate 1 is 0.5 m
If it is m, the thickness t ₁ after optical polishing is set to about 0.2 mm. Similar to the first embodiment, the base substrate 2 serves as a support member when performing the optical polishing, and the lens forming substrate 1 is not chipped or cracked during the optical polishing.

Next, as shown in FIG. 6A, a resist R1 is applied to the one surface 1a side of the lens-forming substrate 1 which has been optically polished, and mask exposure, development and post-baking are performed. Then, high selective ratio etching (reaction gas: CCl ₄ , CF ₄ , C
HF ₃ etc.) is performed to form a concave portion O on the one surface 1a side corresponding to the convex portion of the microlens ML.

Then, after removing the resist R1,
As shown in FIG. 6B, a resist R2 is applied to the one surface 1a side of the lens forming substrate 1, mask exposure, development and post-baking are performed, and only a portion corresponding to a boundary between the plurality of microlenses ML is formed. Try to leave. At this time, the resist R2 is left on at least the bottom surface of the recess O as well. In this state, parallel plate plasma etching (reaction gas: CCl ₄ , CF ₄ , CHF _3, etc.) is performed,
While etching the resist R4 with oxygen, the other surface 1a side of the lens forming substrate 1 is taper-etched.

As a result, with the recess O as a boundary, FIG.
A plurality of micro-prisms MP as shown in are formed on the lens forming substrate 1. After that, the micro prism MP
The transparent electrode 3 is formed on the above with a second resin 12 made of a transparent adhesive having a predetermined refractive index interposed therebetween. The second resin 12 is made of, for example, an epoxy resin or an acrylic resin, and has a refractive index smaller than that of the lens forming substrate 1.

Regarding the method of applying the second resin 12, as in the first embodiment, defoaming is performed in a vacuum so that no air bubbles remain, and heating or ultraviolet irradiation curing is performed. Thereby, the counter substrate 10 is completed.

In the second embodiment, the refractive index of the first resin 11 is smaller than that of the base substrate 2, and the refractive index of the second resin 12 is smaller than that of the lens forming substrate 1. Since the material is used, the convex microlenses ML are formed on the base substrate 2 and the concave microprisms MP are formed on the lens forming substrate 1. However, similar to the first embodiment, Various modes are conceivable depending on the combination of the respective refractive indices.

FIG. 7 is a schematic sectional view for explaining another example of the second embodiment. That is, in the counter substrate 10 shown in FIG. 7A, the refractive index of the first resin 11 is smaller than that of the base substrate 2, and the refractive index of the second resin 12 is smaller than that of the lens forming substrate 1. The rate is smaller.
In such a case, the microlens M is formed on the base substrate 2.
L may be formed in a convex shape, and the microprism MP may be formed in a convex shape on the lens forming substrate 1.

In the counter substrate 10 shown in FIG. 7B, the refractive index of the first resin 11 is larger than that of the base substrate 2, and the second resin is larger than that of the lens forming substrate 1. The refractive index of 12 is smaller. In such a case, the microlenses ML may be formed in a concave shape on the base substrate 2 and the microprisms MP may be formed in a convex shape on the lens forming substrate 1.

Further, in the counter substrate 10 shown in FIG. 7C, the refractive index of the first resin 11 is larger than that of the base substrate 2 and the second resin is larger than that of the lens forming substrate 1. The refractive index of 12 is larger. In such a case, the microlenses ML may be formed in a concave shape on the base substrate 2 and the microprisms MP may be formed in a concave shape on the lens forming substrate 1.

In the present embodiment, the opposite substrate used in the liquid crystal display device has been described as an example of the bonded substrate provided with the micro prism, but the present invention is not limited to this, and a micro lens is provided. It can be applied to substrates that require thin substrates.

[0040]

As described above, according to the method for manufacturing a bonded substrate provided with the micro prism of the present invention, the following effects can be obtained. That is, since the lens forming substrate is polished using the base substrate as a supporting member, the microprism can be formed on the basis of high parallelism and high flatness,
Moreover, since it is not necessary to generate chips or cracks due to polishing, it is possible to manufacture a highly accurate microprism. Further, in combination with the microlens, a bonded substrate having a short distance between the microlens and the microprism can be manufactured with high productivity, and a counter substrate for a high quality and high brightness liquid crystal display device can be provided at low cost. Like

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view (No. 1) for explaining the manufacturing method in the first embodiment.

FIG. 2 is a schematic sectional view (No. 2) for explaining the manufacturing method in the first embodiment.

FIG. 3 is a schematic cross-sectional view (3) explaining the manufacturing method in the first embodiment.

FIG. 4 is a schematic sectional view illustrating another example of the first embodiment.

FIG. 5 is a schematic cross-sectional view (No. 1) for explaining the manufacturing method in the second embodiment.

FIG. 6 is a schematic sectional view (No. 2) for explaining the manufacturing method in the second embodiment.

FIG. 7 is a schematic sectional view illustrating another example of the second embodiment.

[Explanation of symbols]

1 substrate for lens formation 2 substrate for base 3 transparent electrode 10 counter substrate 11 first resin 12 second resin ML microlens MP microprisms R1 to R4 resist

Claims (4)

[Claims] 1. A step of forming a microlens on one surface side of a flat lens-forming substrate, and a plate-shaped substrate on one surface side of the lens-forming substrate on which the microlens is formed via a predetermined resin. Laminating a substrate for a base, polishing the other surface of the substrate for forming a lens to a predetermined thickness by using the substrate for a base as a supporting member, and forming the lens And a step of forming a microprism on the other surface side of the polished substrate, the method for manufacturing a bonded substrate having a microprism. 2. The microlenses are formed by providing recesses with a predetermined pitch on one surface of the lens forming substrate and performing taper etching centering on the recesses. A method for manufacturing a bonded substrate having the microprism according to claim 1. 3. A step of forming a microlens on one surface side of a plate-shaped substrate for a base, and a plate-shaped substrate with a predetermined resin interposed on one surface side of the substrate for a substrate on which the microlens is formed. Bonding the lens forming substrate, and polishing the lens forming substrate to a predetermined thickness by polishing the surface of the lens forming substrate on which the base forming substrate is not adhered, using the base forming substrate as a supporting member. And a step of forming microprisms on the polished surface of the lens-forming substrate, the method for producing a bonded substrate having microprisms. 4. The microlenses are formed by providing recesses with a predetermined pitch on one surface of the substrate for a base and performing taper etching centering on the recesses. A method for manufacturing a bonded substrate having the microprism according to claim 1.