JPS58178690A - Image pickup device - Google Patents

Abstract

PURPOSE:To improve resolution, color reproducibility and sticking accuracy, by placing plural saturation filters for forming a complementary color, on a light incident face of a picture element for forming a complementary color signal. CONSTITUTION:In case when a cyanic filter is constituted of a lot of G filters and B filters, it is shaped like a stripe, a mosaic, etc. in the horizontal direction. In this way, by using many filters for forming a complementary color as a color filter, substantial sampling frequency is raised even in case of an object to be photographed, whose color saturation degree is high, and folded distortion is reduced. Also, a sticking error of the filter to the image pickup element can be offset by the same color filter provided on the circumferential part of this picture element. Also, in this way, the same color filter is placed in front of a boundary in the prescribed direction of the picture element or its vicinity, therefore, a numerical aperture of the picture element is improved, and the sensitivity is raised.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is an improved image pickup device having a nine-color separation filter configuration. Conventionally, for example, a spectral image device of 384X in the horizontal direction and 490 in the vertical direction is applied to White Jl, 11M. 02
Double 2ftac = 7.16 MHIIK @ Mushiru 0 And since the water jF gun output frequency is used to sample the target object that is incident through the optical system such as a lens, the horizontal resolution is
13fm (-a=5.58 kpm) VC phase 4
B minutes! ? If a current receiver is installed, the horizontal resolution fK is a light minute.

I like this - my device is red (R), edge (G), blue (B
) By providing one film for each color of the vase, an S-plate type camera can be constructed, and high-quality color reproducibility can be obtained like a six-tube color camera using three image pickup tubes. Find out about things. - However, the 3a type Katu force meter is composed of a 6 color separation optical system, w
I411 is complicated, making it difficult to miniaturize, and there are drawbacks such as not being able to expect a reduction in price. As a home-use color camera such as this, it is necessary to produce 11 single-chip color cameras that use only one solid-state imaging device.

However, for this purpose, many interlacing points such as K11i and below must be overcome. First, considering solution IIf, a color camera requires three colors, ie, a red light, a green light, and an edge signal. Therefore, in a single-panel type, these three colors must be appropriately distributed.

Color separation filters are used to distribute the three colors, and these can be roughly divided into two types: the Mozuita filter method called Bayer array, and the stripe method in which filters of the same color are arranged in one direction perpendicular to the solid-state imaging device. There is.

Here, to simplify the discussion that follows, let's consider an R, G, and B stripe type color separation filter.

In this case, the number printer frequency of each color in the horizontal direction is a f
c=2.4MHg, and the color signal bandwidth is approximately L2M)1
Become a servant. Therefore, if a brightness signal is created from this color signal, the horizontal layer m degree will be 1/x as low as that of a black and white camera.

In order to comply with the NTSC system and obtain a perfect horizontal resolution using the t, G, B stripe system, it is necessary to significantly increase the number of horizontal frames of the imaging device. However, even in a 1i411ill image device, it is approximately 384'
X 490'<approximately 200,000 elements), and even with the available LSI technology, it would be extremely difficult to increase the number of elements by approximately 6 times.

Therefore, as shown in Japanese Unexamined Patent Publication No. 120281/1981, a method was devised in which the number of Mizu JP sweets was increased by about 50% to about 570 pieces, and a color separation filter shown in FIG. 81 was used.

The feature of this method is that color separation filters are separated from R, G, and B by
G, cyan Gy (Gy2B0G), and the R filter p of the signal obtained from the imaging device when photographing a white subject.
The horizontal layer *[ This is due to the fact that it has improved. However, this theory is based on the premise that many common subjects have low saturation.

That is, as shown in FIG. 6(&), a low-saturation subject image is regarded as approximately equal to a monochrome subject image, and the color signal can be determined. However, this method has the disadvantage that aliasing distortion occurs in highly saturated object images.

That is, when an object of a single color (for example, a red flower) is imaged, the frequency spectrum distribution is assumed to be one.

The signal band is 1 with the band filter LPF 1 in Figure 2 (1).
111j, the sampling frequency depends only on the red signal, so sampling j11#1.
The number is 1/C1.

Then, in the output signal of the solid-state imaging device, a baseband signal (curve wave) and a iris-next side wave amount signal B generated at x 7c 1 are generated.

However, the low-pass filter LPfi' for obtaining the luminance r signal
As shown in IF5 diagram (b), the 1st emitter has a wide band, so the 2nd
The part of the Nine Confucians and the filter LPfi' shown by the line in the figure
Also, considering the color reproducibility in the above method, as shown in No. 3 #1ltalK, filters Fm, Fta,
Spectral sensitivity of a stripe filter composed of Fcy [41
is divided by the spectral sensitivity f of the infrared cut filter for red light, and the sensitivity for cyan light is 1ic c.
Spectral sensitivity of D [41 Because it receives 11X1k due to nature,
Overall spectral sensitivity distribution e red of this imaging device.

The transmittance of each color filter must be set in advance so that the sensitivity distribution is almost uniform for both green and cyan. From the signal SCy corresponding to the light traveling through the green filter FIII, the signal S6 corresponding to the light traveling passes through the green filter FIII.
By subtracting the blue color signal Sa, we obtain the blue color signal Sa.
The spectral sensitivity of the cyan filter is 4it [As shown in Figure 3 fbl, the sensitivity distribution of the blue filter and the sensitivity distribution of the edge filter must be combined so that the overall sensitivity is uniform with the red and edge filters. Nara~・0 However, the conventional cyan color fill! teeth! Figure I3 (Because it has a sensitivity distribution like jLl, the evening color signal SS obtained by the above-mentioned correlation processing differs from the signal that should originally be obtained from the blue filter. There is a drawback.

Next, let us consider the lamination accuracy between the imaging device and the color separation layer filter.

Imaging devices include interline gOcD (IL type), frame transfer deaf CCD (FT type), and MO8.
fi, etc., but here we use #'iFT type CaD to
I will clarify.

tlA4'flJnFTJGcDI) Imaging 1ilC9t
3RWIkft)) is an abbreviation for a channel stopper that prevents diffusion of electric shields between 3ti horizontal elements (details will be described later). The color separation filter shown in the first figure is attached to this. L, S are the incident light transmission (not the bell light layer), ay, R, G are the CT
light.

A color separation filter section that transmits R light and Gjt is used.

The δ channel stopper generally has a negative polarity of 2 to 6P, and the transparent layer LS is usually formed in the same manner as the channel stopper, and is laminated so that 6 and LS completely match.

However, it is extremely difficult to actually improve the lamination accuracy.
There is a problem C1! Uchi, Mechanism n degree of coupling + Dimensions of gI element.

This is because a lamination error occurs due to the movement of Δ.

For example, if the G filter fjl becomes a square ◆ which overlaps the image sensor part of the R filter part due to a coupling error, the final &'J
K: Color mixture occurs in the obtained color signal, and color reproducibility becomes rapid.

There is a request that the width of the Mayu Basubun 111 filter be made as narrow as possible for the light-transmitting layer i-.

This means that the channel stopper 3 also has a certain degree of light reception sensitivity 1.
Since there is, I will take pictures! This is to increase the aperture ratio of the main (light receiving) aperture to increase the overall sensitivity of the camera.0 As mentioned above, the current color separation 1111 filter has a resolution of 1 color reproducibility and a lamination of 1/' The present invention provides an imaging device having an improved nine-filter configuration that can overcome the drawbacks of the prior art.In order to achieve these objects, In the present invention, by frequently using filters to form complementary colors as color filters, the effective sampling frequency is lowered even for bond photographs with high color saturation, reducing aliasing distortion, and the complementary colors can be reduced. Filters to form multiple pure colors!
The main image [
-w O, for example, KB instead of CT filter
By arranging the filter and the G filter in different regions of the same 1IIIE, the spectral characteristics of the complementary color filter can be set arbitrarily, so correct color reproduction can be achieved when performing correlation processing with signals from other j elements. .

Moreover, according to the am example of the present invention, the filter for one color is 11# [
Since it is formed using pure color filters divided in this way, I am jealous of Shuu Ai (・False m is generated even for the subject component.

However, if this aKWII color filter is configured with Il number of pure color filters, 4! By appropriately setting the ratio of the R-color filter to the complementary color filter, it is possible to optimize the compatibility with Rin's IIJlIA.

Furthermore, - of the present invention J111P! According to l, when placing a color #@ filter in a predetermined cocoon, this complementary color filter is used as a plurality of pure color filters! -, and at least one pair of mutually opposing ends of the peripheral part of the stamp, or a similar color fill! - is arranged so that 74 is the bonding vA difference for the voice - to the sensor [this - peripheral area K11l
The kicked Isshiki Filme makes a counterattacking punch.

In addition, since a lung color filter is placed at or near the boundary in a predetermined direction of this IIK pixel, the aperture ratio of the koji layer is improved and the sensitivity is increased. Also, the ^8M component of the subject is relatively cut. This helps reduce aliasing distortion.

The present invention will be described below based on examples.

FIG. 4 is a diagram showing an example of a frame structure of a 7A type (3GD) as an example of a solid-state image sensor according to the present invention, where 1 is a polysilicon (Po) (-8i
), 2 is a photoelectric conversion section, and 6 is a channel stopper. Stiff! Light shielding part LS indicated by KlIN above each channel stop in the horizontal direction of the S-element
The filter and each 1likl cord are aligned so that the filter is placed.

wJ5 Figures (11 to (glL) are diagrams showing configuration examples of the color separation filter of the present invention, and among these examples (1) to (
・) The present invention was applied to FiR, G, and Cy systems.
1"6, me[filter is cyan filter Fcy (t), which is composed of a combination of B filter and G filter, and shows friendly fishing.

Fa is a blue filter, Vθ', Fa Fa is the same spectral feeling!
A green filter having It, FR is a red filter, and instead of using a cyan filter Fay, a blue filter Fbi having a distribution is placed on the --m element. Figure 6 shows the spectral sensitivity characteristics of a filter composed of a combination of Fe' and F@'. If you use the shape synthesized by the area ratio, you can easily obtain a mii-like sensitivity distribution for cyan color as shown in the iris diagram (kl).

Therefore, when this color filter is used in an imaging device,
A color imaging device with good non-fiK color reproducibility can be provided. It goes without saying that the order of the filters Fcy, Fa, and FR is not limited to that shown in the figure.

Figure 5 (Koji ~ (・) is an example of a fan filter composed of a large number of 0 filters and B filters (- is an example of vertical stripes, the same figure ( C1 is an example of a horizontal stripe shape, as shown in the same figure (Q
is an example of a mosaic-like structure, and the same figure (θ) is a diagram showing an example of further subdividing this. Fig. 1 shows an example in which the 7T filter of the mosaic filter is composed of a B filter and a 0 filter.

In addition, in these examples, the cyan filter i! Although only an example in which Dg is achieved by a B filter of one color and a G filter of a pure color is shown, the present invention is not limited to such colors, and can be applied to any complementary color filter.

For example, instead of using a transparent filter, it may be replaced with an appropriate combination of an R filter, a G filter, and a B filter.

Figure 5 (- indicates an example of a filter configuration including such a transparent filter, X indicates a fan filter, Ylj,
The G filter and z are white filters.

As shown in these examples, according to the present invention, the spectral characteristics of the complementary color filter can be set extremely easily, so when the correlation processing of the outputs of adjacent pixels is performed, the color reproducibility is greatly improved. FIG. 6 is a diagram showing another embodiment of the present invention, in which the complementary color filter is composed of a plurality of pure color filters, and the boundary between the color output filter III and other filters or its vicinity is They are the same color. In this example, Cy filter yellow (Ye) filter,
Consider a stripe-type color separation filter that is combined with a G filter.

GOD's channel stock Ytjl 10 Illustrated I
IK Channel St* Ijl between CSt and O8s
The I cumulative KuB and G filters are applied, resulting in pc
An output almost equivalent to that obtained by applying a Gy filter can be obtained.

Also, for example, if we consider the pixel between (381 and C82), the horizontally opposing bases of this - element, that is, C85 and C82, and their neighboring areas P and Q are 0 as the same color.
Even if the color separation filter shifts in the direction of the arrow, the total area of the G filter on the peripheral parts P and Q of the l!il element will not change. When arranging it on the siJ plane, even if it is slightly misaligned, it will not have any effect.

This is the fill for Y in the diagram! IG also about some parts
The same can be said about some filters.

In other words, since the -G filter is placed above the base C83 and GSa of the G filter, even if the filter is misaligned, there will be no effect on the output KFi in the -SCm range between channel stocks '1C8s and 084. does not appear. Therefore, in the manufacturing process, the pupil positions of the color 1111 film or photographing lens are brought close together to prevent 4h color mixture.

Conventionally, when attaching a filter to a COD etc. with an adhesive, the thickness of this adhesive layer must be kept below 10 degrees, otherwise there will be a gap between the filter and the COD, and the pupil position will be far away from the caliber lens. However, according to the present invention, since crosstalk does not occur, a smaller amount of photographic lenses can be used, and the tensile force when the adhesive is cured is reduced. Even if there is a difference in bonding between the filter and the image sensor due to non-uniformity, this can be ignored n+r5〇Also, the precision of attaching the filter, which was conventionally required to be less than 0.5, is now n+r5. For example, it has been confirmed that it can be used up to the range of 6 to 4 voices.

Therefore, it is possible to obtain a structure in which mass productivity is improved, the m-resolution is improved, and color mixing and balance deviation 4 are less likely to occur.

In the seventh embodiment shown in the figure, the boundaries of each filter of the color separation filter are all of a common color.

In this way, the shift of the filter can be offset not only in the horizontal direction but also in the vertical direction.

Note that these configurations can be used instead of adhesive bonding.
It goes without saying that this method is also effective in those in which '4k/- is formed on-chip in the image sensor. In addition, in this case, child safety is further improved.

Color filters are placed in place of the transparent parts on the run, which improves the aperture ratio and increases sensitivity.

can.

The G that accounts for the entire filter is used as a filter.
The ratio of the components increases, and the resolution FItFi is very good (.0).Also, as mentioned above, the color reproducibility is also excellent.

In the above explanation, the carHc of the frame transfer (FT) q was explained, but there is no problem in using an interline (IL) type CGD or a MOS type CGD.

[Brief explanation of drawings]

Figure 1 is a configuration diagram of a conventional R, G, Gy type stripe filter, Figure 2 (&) l (b) is a diagram explaining the aliasing distortion f of the a11 illustrated filter, Figure 6 (IL)
, 1bJ is a diagram explaining the spectral characteristics of a color filter, 8
Fig. 4 shows an example of the configuration of an image sensor applicable to the present invention, Figs. Figure 7 is a diagram showing another embodiment.
... Translucent part, Fa ... Edge filter Fi
I ・-@# Filter, Fcy...-Cyan filter 1lHINaS-person Canon Co., Ltd. Daishijin Marushima Gi-' de-・t 2nd ri (1)), 勺') 2 ton (shi)

Claims (1)

[Scope of Claims] An imaging device that has a pixel that forms a pure color signal and a pixel that forms a complementary color signal, and that excels in a predetermined color signal by performing correlation processing on the pure color signal and the complementary color tS number, An imaging device (f) characterized in that a plurality of pure color filters for forming the complementary color signal are arranged on the light incident surface of the pixel for forming the complementary color signal.