JPH0454921B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention forms a coating film on the side surface of the camera using a spray coating method to block unnecessary light from the outside, thereby preventing optical flare and fogging as a solid-state image sensor camera. The present invention relates to a method of manufacturing a color separation filter for an image sensor.

Solid-state imaging devices, represented by CCDs (charge-coupled devices), are used at the heart of television cameras. In some cases, a separately produced color separation filter is attached to the solid-state image sensor. At present, the latter bonding method is the mainstream because of low manufacturing yields for filters and elements. In the bonding method, the color separation filter is formed on a transparent glass substrate with a certain thickness (for example, about 0.5 to 1.0 mm), so unnecessary light enters from the side of the color separation filter and optical flare occurs. This tends to cause fogging on the camera.

FIG. 1 shows an explanatory diagram of a solid-state imaging device using a conventional color separation filter (no light shielding layer on the side surface).

According to this, a color separation filter 2 is bonded to the light receiving portion (upper surface) of the CCD 1 with the filter layer in contact with the adhesive layer 3 interposed therebetween. The CCD 1 is configured to transmit electrical signals related to images to the outside of the solid-state image sensor package 6 via conductive wires 4 and lead frames 5. A light beam passing through a camera lens system (not shown) is incident on this solid-state imaging device, and a flare prevention plate 8 is provided at the periphery of the lower surface of the sealing glass plate 7, as shown in the figure. It is designed to block unnecessary light that enters diagonally from the outside. When a light beam is incident from an angle, the light beam enters from the side surface of the transparent substrate 9 of the color separation filter 2, causing flare and fogging phenomena, and a flare prevention plate 8 is required to prevent this. Such a flare prevention plate 8 needs to be aligned and installed before the sealing glass plate 7 is installed.
Not only is this process time-consuming, but it is also becoming extremely difficult as solid-state imaging devices have become smaller in recent years.

The present invention has been made in view of the above-mentioned deficiencies of the prior art.
The present invention proposes a color separation filter for solid-state imaging devices that eliminates the need for the above-mentioned flare prevention plate. Specifically, at least a color separation filter layer is formed on one side of a glass transparent substrate in a desired pattern with a predetermined number of colors, and a coating film obtained by a spray coating method is applied to the side surface of a color separation filter for a solid-state image sensor. It is characterized by being formed as a light shielding layer.

Dry plating methods such as vacuum evaporation, sputtering, and ion plating, as well as electroless plating methods, can be considered as methods for forming a light-shielding layer on the side surfaces. It is necessary to create a high vacuum of about 10 ^-4 to ^{10 -5} torr, and there are problems in that the equipment for this is expensive and it takes time to achieve high vacuum.
Furthermore, this case has the disadvantage that the materials that can be used to cover the side surfaces are limited. In other words, a material with corrosion resistance is desired, but these materials include metals such as nickel, chromium, and titanium, which have relatively high melting points, and many oxides have even higher melting points, so they can be used as evaporation sources during vapor deposition. There was a problem in that the color separation filter, which is the substrate, was heated to about 200 degrees Celsius due to the radiant heat, causing deterioration of the organic substances formed on the surface. Therefore, in the case of dry plating, the selection of low melting point materials is limited to tin and aluminum, and since these materials are not corrosion resistant,
There were many inconveniences when using it for a long period of time.

On the other hand, electroless plating can use nickel, which is a material with good corrosion resistance, but in addition to the complexity of the cleaning, degreasing, sensitization, activation, and plating processes, a color separation filter is attached to the liquid. There was an inconvenient aspect in that the liquid seeped into the gap between the color separation filter and the stretchable film 15 that temporarily fixed it and was deposited on the back side of the color separation filter.

In order to improve the above-mentioned drawbacks, the present invention relates to a method of manufacturing a color separation filter for a solid-state image sensor, which is characterized in that a side light-shielding layer of a coating film is formed by a spray coating method.

Here, one embodiment of a color filter for color separation obtained by the manufacturing method of the present invention will be described in detail with reference to FIG.

First, the glass transparent substrate 10 is prepared as described above.
It has a thickness of about 0.5 to 1.0 mm and is made of ordinary glass such as quartz glass, low expansion glass, borosilicate glass, or soda lime glass. A filter layer 11 for color separation is provided on one side of such a glass transparent substrate 10.
The filter layer 11 is an organic film obtained by dyeing a thin film of a photosensitive material of a water-soluble resin such as gelatin, green, casein, etc., photocured, as known in Japanese Patent Publications No. 52-17375 and No. 52-17376. There is a resin-based filter layer, but in addition,
Naturally, an inorganic interference filter layer formed by alternately stacking about 10 to 20 high refractive index thin films and low refractive index thin films such as TiO ₂ to SiO ₂ can also be used.

The thickness of the filter layer 11 is about 10 μm or less, and in FIG. 2, the thickness is greatly exaggerated compared to the transparent substrate 10. Moreover, although it is not clear from Fig. 2, the desired number of colors, for example, two colors of cyan and yellow, or two colors of red and green,
Three colors such as blue are provided corresponding to a desired pattern, that is, the shape of the light receiving section of the solid-state image sensor. In many cases, not only the filter layer 11 for color separation but also an overcoat layer for protecting the surface of the filter layer 11 is added to one side of the transparent substrate 10, or the gaps and surrounding areas of the filter layers of each color are added. There are few examples of color separation filters that are provided with a light-shielding layer and are made up of only a filter layer 11 and a transparent substrate 10.

However, such additional elements for the filter layer 11 are conventionally known, and it goes without saying that the present invention applies to all of these conventionally known color separation filters.

A light shielding layer 12 is provided on the side surface of the color separation filter shown in FIG. 2 by forming a coating film by a spray coating method. The material for this thin film is selected from heat-resistant resins such as acrylic urethane resins, nitrocellulose resins, silicone resins, polyester resins, and acrylic resins as a binder. In addition, black is good for suppressing the reflection of light from inside the color separation filter, which contains colored pigments to give the coating film hiding power to block light, and for that reason, carbon black, acetylene black , graphite, and other pigments are used.

This light-shielding film 12 preferably has a high light-shielding performance with a density of 2.0 or more on the Macbeth densitometer, and in this sense as well, it is desirable to use a black pigment that absorbs light.

The method for manufacturing a color separation filter for a solid-state image pickup device according to the present invention will be described in detail below with reference to FIGS. 3a to 3e of the drawings showing the process order.

As shown in FIG. 3a, the color separation filter for solid-state imaging devices is called "multilayer", and in the filter manufacturing stage, a large number of color separation filter layers 10 are formed on the upper surface of one large transparent substrate 10a. After that, there is a step of cutting each piece. Immediately before this cutting, as shown in FIG. 3a, a protective film 13 is applied to the upper surface of the color separation filter layer 11 formed by multi-sided application to cover the filter layer 11, and an adhesive layer 14 is applied to the lower surface, for example. A stretchable film film 15 such as a vinyl chloride resin film having the following properties is attached.
FIG. 3b shows a state in which cutting grooves 16 have been formed between each color separation filter layer 11 using a dicing device or the like. As is already clear, the protective film 13 prevents the filter layer 11 from being contaminated by the cutting coolant and glass debris generated during cutting. Subsequently, as shown in FIG. 3c, force is applied to spread the stretchable film 15 on both sides as shown by the arrows in the figure, thereby forming the cutting grooves 16.
The width of the groove 16' is enlarged to form a groove 16'. In this state, the color separation filter 18 is cut into individual pieces, and the distance between the side surfaces thereof is widened, so that cleaning of this portion can be easily performed.

After thoroughly washing with water and drying, spray paint to form a coating on the sides.

Spray painting is a method of applying paint by atomizing it using a jet of compressed air sent from a compressor.
Air pressure during work is 1 to 5 kg/cm ² . Place the color separation filter as shown in Figure 3c on a rotating table, and set up a spray gun 10 to 100 cm away from it at an angle of 20 to 70 degrees to spray paint. Gradually turn the rotary table and paint the sides of the color separation filter to a coating thickness of 5 to 100 microns. Thereafter, drying or curing is performed for about 5 to 60 minutes at a temperature of room temperature to 150°C. By performing spray painting in this manner, a coating film 17 is formed on the entire protective surface and side surfaces of the color separation filter 18, as shown in FIG. 3d.

After this, a stretchable film membrane 15 having an adhesive layer is formed.
If the individual color separation filters 18 are peeled off from the protective film 13 with adhesive tape, the color separation filters 18 are separated and independent as shown in FIG. 3e. Then, a coated light-shielding layer 12 is formed on the side surface by spray coating.

Note that the above-mentioned paints are difficult to adhere to smooth glass surfaces, but as in this method, the cut surface has irregularities ranging from minute irregularities of 1μ or less to coarse irregularities of several tens of micrometers, so physical adhesion is not possible. Sufficient strength (removability of Sellotape registered trademark) can be obtained. If even stronger adhesion is required, a silane coupling agent may be applied as a primer.

Examples of the present invention will be described below.

〔Example〕

1 on a transparent substrate made of Pyrex glass (manufactured by Corning, USA) with a thickness of 1.0 mm and a diameter of 10 cm.
A square filter layer with sides of about 10 mm is formed using a known method.
For the 24 multi-layered filter, a coating material "Silitect: trade name manufactured by Controlline, Inc., USA", which is an easily peelable coating film, was applied to the surface filter side and dried to form a protective film. Next, the stretchable tape SPV-224 (trade name, manufactured by Nitto Denko Corporation), which is a stretchable polyvinyl chloride film with an adhesive layer on one side, was laminated to the lower surface of the transparent substrate to form the shape shown in Figure 3a of the drawing. I made it a line.

Subsequently, cutting grooves were cut from the surface using a cutting machine using a 600-mesh resin blade, and the ends of the stretchable tape were pulled to form the state shown in FIG. 3c.
Next, the side surface of the film was coated to a thickness of 20± by spray painting using Toyo Ink Mfg. Co., Ltd.'s black paint (trade name: Lyopol Black (acrylic urethane resin paint)).
A coating film was formed to have a thickness of 5μ. Curing conditions are 80
℃20 minutes.

Thereafter, by peeling off the stretchable tape attached to the back side of the color separation filter and the protective film on the front side, a color separation filter for a solid-state imaging device having a coating layer applied only to the side surfaces was obtained. This nickel layer had a value of 5±0.5 using a Macbeth densitometer, and its adhesive strength was also satisfactory.

As explained above, when the color separation filter of the present invention is formed with multiple color separation filter layers on a single transparent glass substrate, an additional coating process using a spray method is performed during the cutting process. By setting this, the coated light-shielding layer can be applied only to the desired area, ie, the side surface of the filter, and the simplicity of the manufacturing method is of great use in industry.

Furthermore, the coating film light-shielding layer obtained by the present invention has a simpler process and lower equipment cost than metal light-shielding layers obtained by electroless plating or dry plating, and furthermore, because it uses organic materials, It is inexpensive and has high added value as there is no problem of corrosion.

FIG. 4 shows the color separation filter for a solid-state imaging device according to the present invention incorporated into a CCD type solid-state imaging device. As is clear from the figure, since the coated light-shielding layer 12 is applied to the side surface, there is no need to provide a flare prevention plate to the solid-state imaging device, and the solid-state imaging device can be manufactured very easily.

As described above, the method for manufacturing a color separation filter of the present invention is extremely excellent in practical terms because of the combination of simplicity of manufacture and convenience when incorporated into a solid-state imaging device.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing an example of a conventional solid-state imaging device, and FIG. 2 is a schematic cross-sectional view showing an embodiment of a color separation filter for a solid-state imaging device according to the present invention. 3a to 3e are cross-sectional views showing an example of a method for manufacturing a color separation filter according to the present invention in the order of steps, and FIG. 4 shows a state in which the color separation filter according to the present invention is incorporated into a solid-state imaging device. It is an explanatory diagram. 10...Transparent substrate, 11...Filter layer, 1
2... Light shielding layer.

Claims (1)

[Claims] 1. After forming at least a large number of color separation filter layers in a desired pattern with a predetermined number of colors on the top surface of a glass transparent substrate, a protective film is applied to the top surface of the color separation filter layer, and a stretchable film is applied to the bottom surface of the glass transparent substrate. Adhering the film membrane, forming cutting grooves that reach the stretchable film membrane between each color separation filter layer,
After that, the width of the cutting groove is expanded by spreading the stretchable film on both sides, and then a coating film is formed on the entire surface of the color separation filter layer side by a spray coating method, and then the protective film and A method for manufacturing a color separation filter for a solid-state image pickup device, characterized in that by peeling off a stretchable film membrane, a coating film obtained by a spray coating method is formed on the side surface as a light-shielding layer.