JPS61232402A - Color filter and its production - Google Patents

Abstract

PURPOSE:To improve a transparency of the titled filter by laminating a high melting point metal layer capable of an anodic oxidation and an aluminium layer in order, and then by oxidizing the aluminium layer to the alumina layer, and the high melting point metal layer to the high melting point metal oxide layer respectively followed by dying it. CONSTITUTION:A Ta layer 2 is coated on a glass electrode 1 followed by coating the Al layer 3 on the glass electrode 1, and then the anodic oxidation of the Al layer 3 is performed using the electrode as the anode. As the Ta metal layer presents under the Al metal layer, the unoxidized Al metal does not remain on the substrate in a dotted state. And then the anodic oxidation of the Ta layer is performed to form the tantalum oxide layer 12. The anodically oxidized substrate is fully washed with a desalted water, and then dyed. The dyed substrate has the good transparency and is the transparent, vivid, deep pink color, observing from each sides of the substrate, as the Al metal is completely oxidized to the alumina. By the method as mentioned above, the solid color filter not having the unoxidized part of Al, and having a good transparent and an excellent thermal resistance and light fast properties is obtd.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a color filter and a method for manufacturing the same.

(Prior Art) Color filters, or simply filters, are used for the purpose of selectively transmitting and absorbing a predetermined part of the visible part of the original spectrum. Such color filters can be used as filters for light sources for color effects, including color photography lighting, color TV lighting, etc.
It is also well known that it is widely used as a lens filter for photography. In addition to these, they are also often used, for example, as three-color separation filters in portable single-tube television imagers, and in recent years as color filters in color liquid crystal display devices.

Conventionally, gelatin filters, colored glass filters, thin film interference filters, and the like have been widely used as such color filters. Among these filters, gelatin filters are widely used because they have the advantage that they can be provided with arbitrary absorption characteristics and can be formed into fine patterns. However, since gelatin filters are made of protein as a substrate, they have serious drawbacks such as poor moisture resistance, heat resistance, and light resistance. A color filter has been proposed that has the features of the gelatin filter described above and eliminates the above drawbacks, and is formed by dyeing a porous film formed by anodizing Al. Previously proposed A! The method for forming a color filter by anodic oxidation is as follows.

KAJ is deposited on a transparent substrate by vapor deposition, sputtering, etc., and then this AI film is converted into porous alumina by anodization. Such porous alumina is very active and adsorbs dye molecules well. Therefore, a brightly colored film is formed on the transparent electrode.

It is known that such a colored film has very good moisture resistance, heat resistance, and light resistance, and is robust. Details of the AI anodizing method and dyeing method are as follows.

When a voltage is applied between AI as an anode and a cathode in an acidic solution, the surface of AI is oxidized by a generator generated by electrolysis, forming a barrier film with high electrical resistance. Therefore, in order to keep a constant current flowing, K
The applied voltage gradually increases, but when the electrolysis time and voltage reach a certain critical point, the barrier film Fi is selectively dissolved in the electrolyte, forming fine through-holes, and the current flows through these through-holes, increasing the voltage. K so that it also remains constant. and,
The anodic oxidation reaction occurs in the barrier layer at the bottom of the through hole,
A porous alumina film grows approximately in proportion to the flow rate. The holes formed in this way have a diameter of 120 to 300 A, depending on the conditions, and the number is approximately 1010/cx.
It is thought that M. Since the surface of AJ anodized in this manner is porous, it has a large surface area and is highly adsorbent.

colored. Color density can be easily adjusted by adjusting dye density and dipping time. Another feature of AII polar oxide film coloring is that the pores can be easily sealed by boiling or chemical treatment after dyeing, and the absorbed dye is separated from the outside world by the AlzOs film, so it is very stable. It is what happens.

(Problems to be Solved by the Invention) However, in the conventional method of forming a color filter using AII anodic oxidation, it is difficult to completely convert the entire amount of AJ on a transparent substrate into a colorless and transparent porous alumina film by anodic oxidation. Although it is difficult, AJ with a thickness of about 1000 to 3000 Å remains under the alumina film in the form of dots without being oxidized. As a result, when the dyed surface is observed from this surface direction, the uniform color intensity decreases. Furthermore, when used as a filter, the dot-shaped AI blocks light, resulting in a low transmittance.

An object of the present invention is to eliminate the above-mentioned drawbacks, use the AA' anodic oxidation method, remove the acid oxidized part of the AI end, and provide a highly transparent and solid color filter and its manufacturing method.

(Means for Solving the Problems) The color filter of the present invention includes a high melting point metal oxide layer provided by anodizing a high melting point metal that can be anodized on a transparent substrate, and a high melting point metal oxide layer provided on a transparent substrate by anodizing a high melting point metal that can be anodized. The aluminum oxide layer includes an aluminum oxide layer provided on the layer by anodizing aluminum, and a dye that dyes the high melting point metal oxide layer and the aluminum oxide layer.

The method for manufacturing a color filter of the present invention includes the steps of depositing a high melting point metal layer that can be anodized on a transparent substrate and depositing an aluminum layer thereon, and anodizing the aluminum layer to form an aluminum oxide layer. and a step of dyeing the high melting point metal layer with an anodic acid dye.

(Example) Next, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 (al and bl) are cross-sectional views shown in step j@ for explaining the manufacturing method of one embodiment of the present invention.

First, as shown in FIG. 1(a), a glass substrate 1 was selected as a transparent substrate. On top of this, TaS2 was deposited to a thickness of 20 OA by electron gun thermal evaporation, and subsequently a 9AI layer 3 was deposited to a thickness of 3 μm by sputtering.

Next, the AJ layer 3 was anodized using this substrate as an anode at a current density of 1.5 A/d m''.The voltage at this time was constant at about 12V.The AI layer 3 was completely oxidized in about 8 minutes. anodized and converted into a porous alumina layer 13 as shown in Figure 1 (bl).The oxidation of 1.5 A/d
m'' is appropriate, and anodic oxidation proceeds with a constant current and voltage.

In the case of the present invention, since a metal such as 1c Ta is present under the AI, the AI is not oxidized into dots and left behind. Subsequently, the Ta layer 2 was anodized at 0.3A.
/dm" to form the tantalum oxide layer 12. Unlike AI, Ta anodization is dense and has extremely high stain resistance.
A current path is ensured until the thickness of the a-layer 2 becomes several tens of amperes or less. Therefore, the thickness of the Ta layer 2 that remains without being oxidized is several tens of angstroms or less, and is transparent over substantially the entire substrate.

In Ta anodic oxidation, in order to flow a constant current,
As the anodized film grows, the pressure must be increased. The maximum voltage for Ta anodic oxidation was set to 50 V, and the anodizing process was completed when the current decreased to 0.1 mA/dm at this voltage. This anodized substrate was thoroughly washed with demineralized water and then dyed. For dyeing, for example, Alpha Stret manufactured by Oriental Kogyo Co., Ltd. at a concentration of 10 g/l, 60°C.
This was done by immersing the sample in a solution for 30 minutes. After dyeing,
After thoroughly washing with demineralized water again, the tube was boiled in demineralized water for 30 minutes to seal the holes.

Since the substrate q and AI dyed by the above method were completely converted to alumina, the transparency was high, and the substrate was transparent and exhibited a bright deep pink color when viewed from either side of the substrate.

Furthermore, the heat resistance and light resistance were in no way inferior to conventional products.

In the above embodiment, Ta is used as the high melting point metal that can be anodized.
However, in addition to Ta, other high-melting point metals that can be anodized include Nb, Ti, and Zr, and gold ingots of these metals can also be used.

(Effects of the Invention) As explained above, according to the present invention, the Al anodic oxidation method is used, and there is no unoxidized portion of kl, and the transparency is high.
A solid color filter with excellent heat resistance and light resistance can be obtained.

[Brief explanation of drawings]

FIGS. 1A and 1B are cross-sectional views shown in the order of steps for explaining the manufacturing method of an embodiment of the present invention. 1...Glass substrate, 2... Ta layer, 3
...AJ layer, 12 ... tantalum oxide layer, 13 ... alumina layer.

Claims (2)

[Claims] (1) A high melting point metal oxide layer provided by anodizing a high melting point metal that can be anodized on a transparent substrate, and a high melting point metal oxide layer provided by anodizing aluminum on the high melting point metal oxide layer. A color filter comprising an aluminum oxide layer and a dye that dyes the high melting point metal oxide layer and the aluminum oxide layer. (2) depositing an anodizable high-melting point metal on a transparent substrate and depositing an aluminum layer thereon; converting the aluminum layer into an aluminum oxide layer by anodizing; and A method for manufacturing a color filter, comprising the steps of anodizing a metal layer to convert it into a high melting point metal oxide layer, and dyeing the aluminum oxide layer and the high melting point metal oxide layer with a dye. .