JPS58175864A - Solid-state color image pick-up device - Google Patents

Abstract

PURPOSE:To enhance sharply resolution of the solid-state color image pick-up device by a method wherein a first and a second filters, and a third and a fourth filters are made to be adjacent to each other in th perpendicular direction. CONSTITUTION:Photo detecting elements of the plural number arranged in the lateral and the perpendicular directions, and the respective filter elements of mosaic type color filters corresponding to the individual elements thereof are arranged. The first filter is constituted of an adjoining four filter element group of whole color transmitting filters. The second filter is selected from the first- the third spectrum region transmitting filters having respectively the different transmitting characteristics. The third, the fourth filters are consisting of complementary color filters to transmit the transmitting light component of the second filter, and having mutually different transmitting components. The first, the second filters and the third, the fourth filters are adjacent in the perpendicular direction. By adding outputs of two adjoining voluntarily lateral lines, a (2R+G+B) signal, a (R+2G+B) signal or a (R+G+2B) signal can be obtained always, and sharp enhancement of resolution can be attained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a mosaic color filter consisting of a solid-state image sensor in which a plurality of light-receiving elements are arranged both horizontally and vertically, and filter elements arranged corresponding to the light-receiving elements. The present invention relates to a solid-state color imaging device.

There are many conventional solid-state color photographing devices. For example, JP-A No. 51-112228 “
In the color sensor, green transmission filters (G filters) are arranged at every other light receiving element position in both the horizontal and vertical directions as the above-mentioned mosaic color filters, red transmission filters (R filters), Blue transmission filters (B filters) are arranged alternately with G filters in every other row.

In this configuration, since the G filter exists at the highest frequency in both the horizontal and vertical directions compared to the R filter and the B filter, the solution gI curve in both the horizontal and vertical directions is high.

However, in a solid-state photographic device using this mosaic color filter, the light utilization rate is low, the degree of resolution in the diagonal direction is poor, and moiré occurs. There are drawbacks such as a complicated signal processing circuit.

SUMMARY OF THE INVENTION An object of the present invention is to provide a solid-state imaging device that eliminates the drawbacks of the solid-state imaging device described above.

In order to achieve this object, in the present invention, a plurality of light receiving elements are arranged horizontally and vertically, and each filter element of a mosaic color filter is arranged corresponding to each of the light receiving elements. In a solid-state color imaging device, four adjacent filter element groups (2 rows and 2 columns) are
a first filter consisting of a gold transmission filter; a first spectral region transmission filter having different transmission characteristics;
A second filter selected from the second spectral region transmission filter and the third spectral region transmission filter, and a complementary color filter that transmits the transmitted light component of the second filter and has transmission components different from each other. Naru 3rd
, and a fourth filter, wherein the first filter and the second filter, and the third filter and the fourth filter are vertically adjacent to each other. We provide solid-state color photography equipment.

The first region transmission filter, second region transmission filter, and third region transmission filter preferably include a red transmission filter (R filter), a green transmission filter (G filter),
and blue transmission filter (B filter), and these complementary color filters are cyan color transmission filter (Cy filter), magenta color transmission filter (Mg filter),
It means a yellow transmission filter (Ye filter). Further, the all-color transmitting filter (W filter) includes a state in which no filter is substantially arranged.

The feature of the present invention is that when any four adjacent i-th mosaic color filters are taken out, they are always composed of different types of filters, and one of them is always a W filter; The other one is one of the R, G, and B filters, and the other two are complementary color filters that contain the transmitted light components of the filters selected from the R, G, and B filters. There is a certain fact that any four adjacent light-receiving elements, in other words, a mosaic color filter covering the entire surface of a solid-state image sensor, always share one color component among red, green, or blue components. Therefore, the utilization efficiency of light can be greatly improved.And since the first and second filters and the third and fourth filters are adjacent to each other in the vertical direction, arbitrary By adding the outputs of two adjacent horizontal lines, we always get (2R〇+B)
signal, (R+2G+B) signal or (R+G+2 B)
By being able to obtain a signal, a large improvement in resolution g1 degree can be achieved. In particular, when taking out any four adjacent light receiving elements, if one of them is a W filter, the other one is a G filter, and the remaining two are Cy filters and Ye filters, all four light receiving elements receive the green component, so in the diagonal direction If the solution quality of is greatly improved, (R+G) and G signals will be changed from the n-th line, and (G+B) and (R+G-) will be changed from the (n-)-1)th line.
)-B) Since the signals are obtained alternately, the nth row and (n+
1) By simply adding the signals in the row and using a reduction filter, (
R+2G+B) signal band, making it possible to obtain high-resolution video signals.

FIG. 2 shows an example of a signal processing circuit using an 11ffl (11 mosaic color filters).

In this embodiment, since the horizontal grooves of the n-th and (n+1)-th rows are read out in time order, the output signal of the n-th row is delayed by one horizontal scanning period (IH) using the delay means 31 and signal switching. A circuit 32 is present. This signal switching circuit 3
2, the output 32m always receives the (R+G) signal and the G signal, and the output 32b always receives the (G+B) signal and (R+G+).
B) Switch the signal so that the signal is obtained. Then, by adding the Riki Okayama signal from the signal switching circuit 32 in the adding circuit 33 and passing it through the low-pass filter 40, the luminance signal Y can be obtained. This luminance signal Y is always (2G + R + B
) signal, so high-resolution paintings can be played back. Also, by using the subtraction circuit 34 and the low frequency filter 41, the baseband signal of
(R+G), G, (G+B), (R+G+B
) R signals can be obtained using the adder circuit 37.38, the subtracter circuit 39.1 and the low-pass filter 42, respectively.

Note that 43 is a synchronous pulse generation circuit.

Note that in the case of the filter arrangement shown in FIG. 1 (bl), if the circuit shown in FIG. A B signal is obtained as the output of each of 42. Note that when the number of picture elements in the vertical direction is around 250, a delay means 31 and a signal switching circuit 32 are required, but when the number of picture elements in the vertical direction is after 50011J, for example It goes without saying that the delay means 31 and signal switching circuit 32 shown in FIG. 2 are not necessary when using a solid-state photographic device that can simultaneously read the signals of the horizontal lines of a book.

FIG. 3 shows another embodiment. Same figure (JL), (
In el, all four picture elements include red as a transmitted component, and in the same figure (bl, (dl) include blue as a transmitted component, and the vertically adjacent nth and (n+1)th rows of light-receiving elements, respectively, When the signals are added, (2R+
G+B ) signal and (R+G+2 B ) signal are always obtained.

The fourth embodiment of the signal processing circuit in the same figure (al.
As shown in the figure. From the solid-state sensor equipped with the mosaic color filter shown in Fig. 3(a), the (G+R) signal and R
The signal is (R+B) signal and (R+B) signal on the (n+1)th line.
+G) signals are obtained, so the signals of the n-th and (n+1)-th rows are separated using the delay means 31 and the signal switching circuit 32, and then added by the adding circuit 33, and then passed through the low-pass filter 40. By doing so, a (2R+G+B) signal is obtained. In addition, a subtraction circuit 34 calculates the difference between the two, and a low-pass filter 4
1, the R signal can be obtained by synchronously detecting the B baseband signal, the nth row signal, that is, the (c+R) signal, and the R signal in the synchronous detection circuit 44, and then passing it through the low-pass filter 45. . The output of the low-pass filter 40 may be used directly as the brightness signal, but brightness distortion occurs because the mixing ratio of the brightness signal and the R, G, and B signals specified by the NTSC color television system is significantly different. . Therefore, it is necessary to subtract the R and B low-frequency components (500 KHz or less) in the matrix circuit 46 to obtain a luminance signal Y' without luminance distortion.

Note that this signal processing circuit may also be used in the case of the filter arrangement shown in FIG. The output of the signal and low-pass filter 45 becomes the B signal.

Next, FIG. 5 shows an embodiment of the signal processing circuit when the mosaic color filter of No. 31J(c) is used. In this figure, the blocks having the same numbers as those in FIG. 4 are the same. Figure 3 (In the case of cl, the (G+R) and (R+G+B) signals start from the nth line, and the (R+B) signals start from the (n+1)th line.
) signal and R signal are obtained. Therefore, the low pass filter 4
For the output of 0, a (2R〇+B) signal is obtained. The signal switching circuit 32 always provides (R+B) to the synchronous detection circuit 44.
) signal and the R signal are introduced, (R+B) and the R signal are separated, and the R signal is passed through the low-pass filter 45.
A (R+B) signal is obtained by passing it through a low-pass filter 47, and a B signal is obtained by subtracting it in a subtraction circuit 48.

In this case as well, if the (2R+G+B) signal is used as a luminance signal, luminance distortion will occur, so R,
By subtracting the low frequency component of H (50'0 KHz or less), a signal without brightness distortion can be reproduced.

Note that this signal processing circuit may also be used in the case of the filter configuration shown in FIG. 3(d). At this time, the output of the low-pass filter 40 is a (R+G+2B) signal, and the output of the low-pass filter 45 is a B signal.
The output of the subtraction circuit 48 is the R signal.The synchronous detection circuit 44 also receives the signal of the hth row, that is, (R+B
) signal and the B signal are introduced.

Now, FIGS. 6 to 9 show embodiments of the second group of the present invention. This group of embodiments can be considered as a modification of the first group of embodiments.

The feature of this embodiment group is that any adjacent 4 rows and 2 columns (4 in the horizontal direction) of the mosaic color filters disposed in front of each light receiving element have the following configuration. W
The filter is the first filter, one of the R filter, G filter, or B filter is the second filter, and the second filter is selected from among the three complementary color filters of the Ye filter, the Cy filter, and the Mg filter. The two types of filters that transmit the transmitted light are used as third and fourth filters, and these filters that transmit the transmitted light of Two second, third, and fourth filters are included in each of the adjacent four rows and two columns of light receiving elements;
The two light-receiving elements are arranged at positions shifted by two picture elements in the horizontal direction and one light-receiving element in the vertical direction. In other words, in the case of the third group of embodiments, the predetermined filters for four adjacent light-receiving elements arranged in two rows and two columns were periodically arranged with two light-receiving elements each in the horizontal and vertical directions. On the other hand, in the case of the present embodiment group, the filter for four adjacent light receiving elements in arbitrary 2 rows and 2 columns has the structure of the third embodiment group, and two light receiving elements are arranged periodically in the vertical direction. However, in the horizontal direction, the mosaic filters in the n rows and (n+1) rows are alternated every two light receiving elements.

No. 61 is the first example of this group of examples. At this time, the signal output of the nth row has a carrier wave as shown in Figure 7(b) for red light, a carrier wave as shown in Figure 7(b) for blue light, and a carrier wave as shown in Figure 7(b) for green light. There is no pull, and it becomes a baseband signal. That is, the carrier waves of red light and blue light have the same frequency but are out of phase by 90°. The signal output of the (n+1)th row is similar, but the carrier waves for red light and blue light are respectively shown in FIG. ing.

Therefore, by guiding the solid-state gI signal output to a low-pass filter and a bandpass filter, (R+
Since the carrier waves of the R and B signals are changed from the output of the bandpass filter, the R and B signals can be obtained by synchronously detecting the 2G1B) signal. In this filter arrangement, the carrier waves of the R and B signals are inverted in phase for each row, so the baseband signal is mixed into the carrier waves of the R and B signals. From figure 1 @5
This will be explained using figures. The feature of this embodiment is that when focusing on four arbitrary adjacent light-receiving elements arranged in 2 rows and 2 columns, the filter element corresponding to - light-receiving elements is a W filter, and the light-receiving element equipped with this filter The filter element corresponding to the vertically adjacent light receiving element is a type of filter selected from the R filter, G filter, and B filter, and the filter element corresponding to the other two light receiving elements is a type of filter selected from the R filter, G filter, and B filter. The reason is that these are two different complementary color filters whose transmitted light is the transmitted light of the filter.

FIG. 8 shows one embodiment of this group of embodiments. The signals of the picture elements located at the corner positions of the mosaic color filters shown in FIG. Get a signal.

It should be noted that if the filters for the four picture elements in FIGS. Although the case of FIG. 1 (11) is illustrated, it goes without saying that the present signal processing circuit can be used in other embodiments in FIG. 1 and embodiments in the second group.

The present invention has been described in detail above, but from the first embodiment onward, we will discuss the mosaic method that can always obtain a constant signal for each pixel in the horizontal direction when the signals of two adjacent horizontal scanning lines are added. The structure of the filter is disclosed. This is very effective in improving the resolution g11 degrees in solid-state imaging devices. This filter configuration is especially effective when applied to an interlaced solid-state sensor that reads two adjacent horizontal scanning lines simultaneously.

As another embodiment, it is also possible to first subtract the signal outputs of the bandpass filters 2 and 2' to obtain a multiplexed signal of R and B signals using only two synchronous detectors.

FIG. 9 shows another mosaic color filter structure of this embodiment group. Similarly to FIG. 6, in FIG. 6(a), R and B signals are used as carrier waves. -) and (e) both use R and G signals as carrier waves, and the (R+G+2B) signal is the baseband signal, and (d) and <61 both use G signals as carrier waves.
This is an embodiment in which the and B signals are used as carrier waves and the (2R+G+B) signal is used as the baseband signal. It goes without saying that the signal processing circuit shown in FIG. 8 is effective in these embodiments as well.

In addition, in the case of the filter configuration of the first group and the second group, other embodiments can be considered as the signal processing circuit.

An example of the filter configuration shown in FIG. 1 will be described using FIG. 1θ. As explained earlier, the nth line and (n+
1) By simply adding the signals in the row, (R+2G1B) signals are obtained for each horizontal can light-receiving element. On the other hand, subtracting the signals of adjacent light receiving elements in the same row gives (Ye-G)=R, (cy-w) --R, and subtracting the signals of the diagonal light receiving elements, (Ye-G)=R, (cy-w) --R.
W)=-B.

(Cy-G)-B. This embodiment utilizes this fact. In FIG. 1θ, the signals that have passed through the low-pass filter are added by an adder circuit 33 to become a (R+2G+B) signal. 61 to 64 are delay circuits for one light receiving element.

Then, in each of the n and (n+1) rows, a subtracter 65 .
66 to obtain the R or -R signal. Then, polarity inversion circuits 69 and 70 are used to unify the polarities, and addition circuit 73 adds the signals to obtain an R signal. On the other hand, similarly, the subtraction circuit 6
7.68 is used to subtract the signals of the light-receiving elements located at diagonal positions, polarity inversion circuits 71 and 72 unify the polarities, and addition circuit 74 adds the signals to obtain the B signal. It should be noted that if the filters for the four picture elements shown in FIG. Although the case of FIG. 1 (&) is illustrated, it goes without saying that the present signal processing circuit can be used in other embodiments in FIG. 1 and embodiments in the fourth group.

Now, the following can be considered as a modification of the fourth group. Now, let F represent the filter configuration shown in the third group, and let F be the filter element with the columns of this F changed, and IF with the rows changed, then the filter configuration of the fourth group is F.
It is expressed as IF, but as a variation of this, the following is also a high resolution gI! It is possible to obtain degrees.

Similarly, F, F, and IF were arbitrarily selected and placed adjacent to each other.

1'@ll'lt"-klIt"-F' I
High resolution can also be obtained for F@l, 1F-IF, etc.

According to the present invention described in detail above, the light utilization rate is high;
It becomes possible to obtain a solid-state color photographing device with high resolution.

[Brief explanation of drawings]

FIGS. 1 to 5 are diagrams showing the first embodiment of the present invention, and FIG.
9 to 9 show the second embodiment, and FIG. 10 shows the first embodiment.
FIG. 7 is a diagram showing another signal processing circuit used in the second embodiment. 86 Old car 7 Hair opening! θ Continuation of Figure 1st page 0 Inventors: Moriji Izumida, Hitachi, Ltd. Central Research Laboratory, 1-280 Higashi-Koigakubo, Kokubunji City, Hitachi, Ltd. 0 Inventors: Kenji Takahashi, 1-280 Higashi-Koigakubo, Kokubunji City, Hitachi, Ltd., 0 Inventions Mita area - Hitachi, Ltd. Central Research Laboratory, 1-280 Higashikoigakubo, Kokubunji City

Claims (1)

[Scope of Claims] 1. A solid color filter including a mosaic color filter consisting of several photodetectors arranged in horizontal and vertical directions and filter elements arranged corresponding to each of the photodetectors. In the imaging device, four adjacent filter elements constituting the mosaic color filter are a first filter consisting of an all-color transmission filter, a first spectral range transmission filter and a second spectral range transmission filter each having different transmission characteristics. filter, a second filter selected from the third spectral region transmission filter, and third and fourth complementary color filters that transmit the transmission component of the second filter and have mutually different transmission components. What is claimed is: 1. A solid-state color photographing device comprising: a filter, wherein the @l filter and the second filter are vertically adjacent to each other. 2. The first filter and the second filter switch positions every two light receiving elements in the horizontal direction, and the third filter and the fourth filter switch positions every two light receiving elements in the horizontal direction. The solid-state color photographing device according to claim 1, wherein the position is changed. 3. Q) A solid-state color photographing device as set forth in claim 1, comprising means for simultaneously and separately reading out optical signals of two horizontally adjacent light receiving elements of the light receiving element. 4゜Two outputs of the above-mentioned reading means) A feature having means for adding J! F. A solid-state color photographing device according to claim 3.