JPS6167003A - color image sensor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an image sensor suitably used in color television cameras, color image reading devices, and the like.

[Conventional technology]

Conventionally, color image sensors incorporated in color television cameras, color image reading devices, etc. basically consist of an image sensor body such as COD, and a mosaic or stripe shape attached to the light receiving surface of this body. A color separation filter having a pattern is known.

゛However, a color image sensor with such a configuration
In this case, the effective aperture ratio (ratio of the area of the light-receiving surface to the area occupied by the light-receiving cell) of the image sensor such as COD used as the main body is low, and the light-receiving surface where the light-receiving cell of the image sensor main body is arranged is low. All of the light that reaches the image forming the optical image cannot be received by the light receiving cell and efficiently converted into an image as an electrical signal, making it impossible to obtain sufficient performance in terms of resolution, etc. Due to structural problems, it was difficult to apply it to devices that required higher performance.

Therefore, in order to apply it to devices that require higher performance, we have developed a conventional color image sensor with the above configuration.
As a means of increasing the effective aperture ratio of a color image sensor, it is known to provide a condenser lens corresponding to each of the light receiving cells of the color image sensor.

The configuration of a color image sensor equipped with a condensing lens to increase the effective aperture ratio is, for example: (1) A glass, which is an assembly of condensing lenses formed in advance, on an image sensor body made of COD, etc. A lens array consisting of a material such as gelatin, poval, etc. is attached so that each condenser lens of the lens array corresponds to each light receiving cell of the image sensor, and a parent tree such as gelatin or poval is attached onto the condenser lens. (2) A structure in which a so-called dyed-type color separation filter is attached, which is obtained by forming a desired pattern with a synthetic resin and dyeing the pattern with a dye. A photoresist is patterned on a dyed color separation filter with a similar configuration so that the resist remains in an island shape at a location corresponding to each light-receiving cell, and then this is heated and the surface of this resist is (3) A structure in which the image sensor main body is deformed to have a spherical shape to form a lens array having a plurality of condensing lenses corresponding to each of the light receiving cells of the image sensor main body, and (3) an image sensor main body consisting of a COD, etc. First, a lens array having a plurality of condensing lenses corresponding to each of the light receiving cells of the image sensor body is formed on the light receiving surface in the same manner as in (2) above, and then dyeing is applied onto the lens array made of resin. There are three typical types of configurations in which color separation filters are attached.

[Problem that the invention seeks to solve]

However, in the color image sensor configured as in (1), when the color separation filter is attached onto the lens array using an adhesive.

On these adhesive surfaces, the unevenness formed by the functional surface (light-receiving surface) of the condensing lens of the lens array is filled with the adhesive, weakening its function as a condensing lens, and color separation. Because the colored part of the filter and the light-receiving part of the image sensor body are provided relatively far apart, the light that has passed through different color filters may overlap while the light passes from the color separation filter to the image sensor body. There were structural problems such as mixing of colors, that is, color mixing.

On the other hand, in the color image sensor having the configuration (2) above, the colorant contained in the dyed type color separation filter used as the color separation filter is
In the process of forming a lens array, which is a collection of condensing lenses made of resin, on the color separation filter, the color tends to change due to the influence of heat applied, and the function as a color separation filter is impaired. There was a problem with putting it away.

On the other hand, in the case of a color image sensor having the configuration (3) above, the lens 7 ray is first formed on the image sensor body, and then the colored filter is attached, so it cannot be used as a colored filter. Although there is no effect of heat on the dye contained in the filter and there is no problem of discoloration of the colored portion of the filter, similar to the color image sensor formed by method (1), the colored portion of the color separation filter and the image sensor are Since the light receiving section of the main body is provided relatively far away, there is a problem in that color mixing is likely to occur.

As described above, color image sensors that satisfy configurations (1), (2), or (3) above each have the above-mentioned problems, and the effective aperture ratio is insufficient. At present, a color image sensor with high quality and good functionality is not yet known.

An object of the present invention is to provide a color image sensor having a sufficiently high effective aperture ratio and excellent functionality.

[Means to solve problems]

The above objects can be achieved by the following invention.

Namely, the color image sensor of the present invention includes, on a light-receiving surface on which a plurality of light-receiving cells are arranged, a colored filter made of a vapor-deposited layer of a dye corresponding to each of the light-receiving cells, and a condensing lens made of a photosensitive resin. are provided in this order from the light-receiving surface side.

Hereinafter, the color image sensor of the present invention will be explained in detail using the drawings.

FIG. 1 is a schematic partial cross-sectional view of an example of the color image sensor of the present invention, taken along the direction in which light receiving cells are arranged.

The color image sensor of the present invention basically includes a main body portion 1 in which a plurality of light receiving cells 2-1 to 2-5 are arranged at predetermined positions, and a light receiving surface 1a of the main body (the light receiving cells of the main body portion A plurality of filters 3-1 to 3-5 and a plurality of condensing lenses 4 are provided at positions corresponding to the respective light receiving cells 2-1 to 2-5 on the surface on which the received light is incident.
-IN4-5.

In this device, light that enters the condenser lens 4-1 and passes through the filter 3-1 is received by the light-receiving cell 2-1. Similarly, other condensing lenses 4-2
The light incident on each of the light receiving cells 2-2 to 2-5 also passes through each of the filters 3-2 to 3-5 corresponding to these condensing lenses, and is received by each of the light receiving cells 2-2 to 2-5. Ru.

The main body portion 1 of the color image sensor of the present invention is a CC
D, BEi), MOS, etc. can be formed using a device used as a normal image sensor.

On the light receiving surface Ia of this main body portion 1, light receiving cells 2-1 to 2
The plurality of filters 3-1 to 3-5 provided corresponding to each of the filters 3-5 are provided as vapor deposited layers made of a sublimable dye that can be vapor deposited. Each filter corresponding to multiple light-receiving cells is color-coded to have a predetermined function as a single-color separation filter when attached to a color TV camera, color image reading device, etc., and is suitable for the purpose. It is molded into a pattern.

The sublimable dye that can be deposited and which can form the filter of the color image sensor of the present invention includes:
Examples include acetoacetic anilide dyes, monoazo dyes of naphthols, polycyclic dyes, dispersion dyes, oil-soluble dyes, indanthrene dyes, and phthalocyanine dyes. It is sufficient to select and use the appropriate color depending on the color.

Among these dyes, phthalocyanine dyes, perylene dyes, isoindolinone dyes, anthraquinone dyes, quinacridone dyes, etc. have good spectral characteristics and are heat and solvent resistant as vapor-deposited dye layers. It is preferable because it is excellent.

A plurality of light receiving cells 2- of the color image sensor of the present invention
Condenser lenses 4-1 to 4 provided corresponding to lenses 1 to 2-5
-5 is made of photosensitive resin and has a functional surface 4a on its upper surface that receives light, and the light collected by this functional surface 4a passes through a filter and is sent to a light receiving cell.

In the color image sensor of the present invention.

By providing this condensing lens 4-IN4-5 continuously over the entire light-receiving surface 1a of the image sensor body, the light that reaches the light-receiving surface 1a and forming an optical image is efficiently transferred to the light-receiving cell. This makes it possible to increase the effective aperture ratio sufficiently.

Examples of materials for forming the condensing lenses 4-1 to 4-5 include ordinary ultraviolet and deep ultraviolet resists, including polymethyl methacrylate, PMIPK, polyglycyl methyl acrylate, A positive far-ultraviolet resist such as a phenol novolac type resist is preferred because it softens at a relatively low temperature and is easy to form a condenser lens shape, and has a high transmittance for light used as an image sensor.

The color image sensor of the present invention having such a configuration is as follows:
For example, it can be formed as follows.

First, as shown in Fig. 2, the light receiving surface l of the main body portion is
After forming a resist layer 5 by laminating, for example, a positive photoresist on the surface of a by a method such as coating, the resist layer °
5 is exposed to light through a photomask 6 having a desired pattern as shown in FIG. 3, and developed with a developer.
A resist pattern 5a for lift-off as shown in FIG. 4 is obtained.

Next, as shown in FIG. 5, on the light-receiving surface la of the main body provided with this resist pattern 5δ, one or more dyes suitably selected from the above-mentioned dyes are vapor-deposited to form a first color. A dye vapor deposition layer 7 is formed.

The light-receiving surface 1a on which the vapor-deposited layer 7 is formed in this way is treated with a photoresist removal solution, and the photoresist layer 5a and the vapor-deposited layer 7a formed thereon are removed together from the light-receiving surface. Then, a colored pattern of the color @l consisting of the vapor deposited layer 7b is formed as shown in FIG.

Thereafter, the process for the first coloring pattern described above is repeated for the second color and the third color by changing the dye used in order, thereby forming the second coloring pattern 8 and the third color. The coloring patterns 9 are respectively formed to form a color separation filter 10 consisting of a three-color coloring pattern as shown in FIG.

In addition to the lift-off method described above, other pattern forming methods such as dry etching can also be used to pattern the vapor-deposited dye layer.

Next, a photoresist as mentioned above is laminated on the color separation filter O by a method such as coating, and the layer is subjected to 7-knealing under predetermined conditions to remove resin debris 11 as shown in Fig. 148. Form. Furthermore, a photoresist similar to or different from the photoresist used previously is laminated on the resin 7511 by a method such as coating to form a photoresist layer 1.
2 is formed as shown in FIG.

Here, as shown in FIG. 10, photoresist 12a is applied in an amount necessary for the functional surface of the condenser lens to have a predetermined shape at each position corresponding to one individual light receiving cell using the photolithography method. The photoresist layer 12 is patterned using a pattern forming method such as a lift-off method or a dry etching method so that the photoresist layer 12 is left in a predetermined shape.

The patterned photoresist 12a at this time
The shape of is determined by various conditions in the subsequent 72-ring, 7
It may be selected as appropriate depending on the shape of the functional surface of the condensing lens formed by the two-ring, the type of resin used, etc.

Finally, the photoresist 12a, which has been patterned into a predetermined shape, is softened by a double ring.

Fluidize and transform the rectangular cross-sectional shape into a circular arc shape.ml1
A condenser lens 4 is formed as shown in the figure.

The color image sensor of the present invention formed in this manner includes a solid-state image sensor as a main body portion, and a solid-state image sensor as a main body portion.
The basic structure includes a colored filter made of a vapor-deposited layer of dye corresponding to each light-receiving cell of the main body part, and a condensing lens formed of photoresist. The effective aperture ratio has become sufficiently high, making it possible to use it in devices that require high sensitivity.

Moreover, the colored filters provided corresponding to each light-receiving cell in the main body part are formed of a vapor-deposited layer of a heat-resistant dye, and one colored filter may change color during the process of further providing a condensing lens on top of the filter. Also, because the colored filters provided corresponding to each light receiving cell of the main body are provided close to the light receiving cells,
It has a structure in which mixing of the lights that have passed through each filter, that is, color mixing, is less likely to occur, resulting in a color image sensor with good functionality.

The color image sensor of the present invention will be explained in more detail below using Examples.

Example 12 First, a color separation filter in a mosaic pattern consisting of three colors of cyan, red, and green was attached using the lift-off method on the interline transfer CCD as the main body part in which 400 x 490 ga x 20 u light receiving cells were arranged. It was formed as follows.

First, a positive photoresist (trade name, 0FPR800, manufactured by Tokyo Ohka Co., Ltd.) was used on the light-receiving surface of the main body where the light-receiving cell was installed, except for the part where the cyan color filter was to be provided, and the pattern exposure, development, etc. , an undermask for lift-off was provided. Next, a layer of copper phthalocyanine with a thickness of 0.3 g was deposited on the light-receiving surface provided with this undermask, and then this surface was treated with a developer to remove the undermask from the light-receiving surface. A cyan filter consisting of a deposited layer of copper phthalocyanine patterned into a predetermined shape was formed at a distance of 'A' from the sample.

Thereafter, the process of forming such a cyan color filter was repeated by using Irgazine Red instead of copper phthalocyanine to form a red filter, and further by replacing the pigment with lead phthalocyanine to form a green filter, which was used as a color separation filter. .

After the color separation filter was formed, a phenoltuborac-based positive far-ultraviolet resist (trade name, A22400 DUV, manufactured by Sibley) was coated on the color separation filter to a thickness of 6 mm, and this layer was coated with a 170 mm thickness. The resin layer was annealed by heating at ℃ for 60 minutes.

Next, the same photoresist as above was further applied to a thickness of 3 μs on the previously formed resin layer, and patterned by photolithography, forming stripe-shaped unexposed portions at 3-μs intervals. It was placed corresponding to the light receiving cell.

Finally, the unexposed portion of the photoresist thus provided is annealed by heating at 170° C. for 60 minutes to transform the end surface into a spherical shape, which becomes the functional surface of the condenser lens.
In addition, the resin layer provided first and the resin layer laminated later to form a functional surface were integrated.

The effective aperture ratio of the color image sensor of the present invention formed in this manner is approximately 80%, whereas the COD of the interline transfer used in the main body portion is approximately 40%. No discoloration of the thinly colored pigmented layers of each color is observed, and furthermore, no mixing of light passing through the filter is observed during use, ensuring good functionality, such as color TV cameras and color image reading devices that require high sensitivity. This color image sensor is suitable for installation in cameras.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional partial view of an example of the color image sensor of the present invention, and FIGS. 2 to 11 are process diagrams showing the steps for forming the color image sensor of the present invention. 1; Image sensor body portions 2-1 to 2-5; Light receiving cells 3-1 to 3-5; Colored filters 4-1 to 4-5; Condenser lens 4a; Functional surface 5.12; Resist layer 5a; Resist pattern 6; photomasks 7a, 7b; vapor deposited layer 8 of first color dye; vapor deposited layer 9 of second color dye; vapor deposited layer 1O of third color dye; color separation filter 11; resin layer

Claims (1)

[Claims] 1) On a light-receiving surface where a plurality of light-receiving cells are arranged, a colored filter made of a vapor-deposited layer of dye corresponding to each of the light-receiving cells and a condensing lens made of a photosensitive resin are placed in this order from the light-receiving surface side. A color image sensor characterized by being provided with a color image sensor.