JPS61234188A - Solid-state image pickup device - Google Patents

Abstract

PURPOSE:To simplify a signal processing circuit and obtain a picture of good quality by replacing a vertical selecting switch by a circuit having a function for splitting a color signal passing through a horizontal output line into three signal output lines every color signal. CONSTITUTION:A splitting circuit 9' having the function for selecting a horizontal output line read during a horizontal image period and connecting to a signal output line and the function for splitting the color signal passing through the horizontal output line during the horizontal image period to the respective signal output lines every color signal is provided. The color signals outputted as output signals S1-S3 become constantly the same color signals S1', S2', S3' or S1'', S2'', S3'' during 1 field period, so that a switching circuit as an outer circuit is a simple circuit for switching S2 and S3 every field and a signal processing circuit is simplified. Since the color signal is outputted constantly through the same preamplifier during the 1 field period, a picture of good quality having no line crawling produced resulting from an unevenness in amplification factor of the preamplifier can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a solid-state imaging device for a color television camera, and more particularly to a MOS-type solid-state imaging device in which photoelectric conversion elements are sequentially scanned by an X and Y switch matrix. It is something.

[Background of the invention]

A solid-state imaging device is a solid-state device that integrates a two-dimensional array of pixels with photoelectric conversion and storage functions, and a circuit with a scanning function that sequentially extracts signal charges accumulated in each pixel in time series. It is.

Among these, the scanning method is an X, Y address scanning type (MOS type) using an X, Y switch matrix.

It is divided into a charge transfer type that uses a COD, which has a self-transfer function, and a BBD, etc.

Figure 1 shows the already proposed patent application No. 58-18588.
This figure shows the circuit configuration of the MO8 type solid-state imaging device detailed in the above issue.

11.12. . . . The signal charges accumulated in each photodiode of mn are read out in the following procedure. That is, in the first field, interlace and switch 1 are connected upward. Then, during the horizontal blanking period, the vertical scanning lines 10 and 20 are selected by the vertical shift register 2, and the vertical switches 3 and the superposition selection switch 9 in the two rows connected thereto are turned on.

When the horizontal video period begins, the horizontal switches 5 are sequentially turned on by the horizontal shift register 4 to turn on the photodiode arrays 11 . ...1n and 21. ......, 2n
The signal charges of the output signal S1.
Output as S. Similarly, the signal charges of the photodiode columns are sequentially read out in two rows for each horizontal video period.
In the second field, in order to perform an interlace operation, the interlace switch 1 is connected downward, and the same operation is repeated by changing the combination of the two rows of photodiode columns to be read out at the same time.

To make a single-chip color camera using this device, each photodiode must be equipped with color filters of three or more colors, such as cyan,
Yellow, green and all colored lights (hereinafter referred to as Cye Y6)
It is necessary to arrange a filter that transmits # G p W) as shown in Figure 1, and separate and synthesize the Y signal Sy and the two color signals SIl and S, which are necessary for the television signal, from the obtained signal. There is.

By the way, the noise of the MO8 type element has a triangular noise distribution, and its level increases approximately in proportion to the frequency. Therefore, it is desirable to create a television signal only from the baseband component of the output signal, which has a low frequency and low noise, but in the device shown in FIG. 1, the output signal is two independent signals S1. Since only the baseband components S and t are output, it is not possible to create the three independent signals Sv, Swa, and S required for the television signal.

This drawback can be eliminated by modifying the device shown in FIG. 1 so that it can output three independent signals as shown in FIG. In the figure, for simplicity, each photodiode is represented by a square, and the color of the light transmitted through the filter above each photodiode is indicated in the square. The device shown in FIG. 2 divides the signal charges of two rows of photodiode columns, which are simultaneously read out, into three horizontal output lines, for example 99, 100, 200, that sandwich them, and generates three independent output signals S, , S, , S. Therefore, as shown in FIG.
．． Subtractors 71, 72 and reduced waveforms 6', 7',
By using the signal processing circuit 7', it is possible to generate S, , S, , S, necessary for the television signal from only the baseband components of S, ~S, with low noise level, and eliminate the above-mentioned drawbacks.

However, on the other hand, with this element, 81
~S3 as 51=Ya=Syu'S,=W+Cy=8. 'S,=G =S,' is output, whereas in the next horizontal video period, s1=w
+cy=s,'S,=G=S,'S,=Ye=S,' are output, and each output signal 81-S,
The types of color signals S, / to 3, / that are output as are switched. However, W, G, . . . , etc. represent signal charges obtained by transmitted light of the colors marked with the same symbol W, G, . . . , etc. In the second field, each color The type of signal changes as follows: S = w = s, ' 53 = G + Ye = 82' S2 = Cy = 81', but like the first field, it is output in 81 to 8, switched every horizontal video period. .

Therefore, the signal processing circuit of this element has an output signal S□~
S, is the color signal S□′~3,7 for each horizontal video period
Alternatively, a switching circuit 60 that switches between S, ′ and S
1 (The sign inverting circuit 603 and the switch circuit 602 convert the color signals S, /~S, I and s1' for each field.
(This is a circuit inserted in order to change xsa') is required. This circuit has a complicated configuration because it is necessary to replace all three output signals every horizontal period. In addition, the preamplifier to which each color signal S1' to S, 1, etc. is output differs for each horizontal video period, and if the amplification factor varies, the amplitude of S, , S, and Sa changes for each horizontal scanning line of the television signal. It has the drawback of significantly degrading image quality.

[Purpose of the invention]

An object of the present invention is to improve such conventional problems and to externally convert the output signal for each horizontal period into a color signal of 81' to S%.
It is an object of the present invention to provide a solid-state imaging device that does not require separate replacement and does not cause line roll due to variations in the amplification factors of three preamplifiers.

[Summary of the invention]

To achieve the above object, the present invention provides a horizontal output line 100
~ m00 and the signal output lines 101, 201° 301, and instead of the vertical selection switch 9 that serves to connect the horizontal output line from which signal charges are read out and the signal output line, a color signal 81' that passes through the horizontal output line is added. ~83' or 81'
The feature is that ~S,' is replaced with a circuit that has the function of distributing each color signal to three signal output lines, or that the replacement circuit is built into the element output terminal section of the element shown in FIG.

[Embodiments of the invention]

The present invention will be described in detail below with reference to Examples.

FIG. 4 is a diagram showing the structure of a solid-state imaging device according to the present invention. In @, 9' has the function of selecting the horizontal output line to be read during the horizontal video period and connecting it to the signal output line, and the function of distributing the color signals passing through the horizontal output line during the horizontal video period to each signal output line for each color signal. This is a distribution circuit that does this.

An embodiment of this circuit is shown in FIG. 5. This circuit is driven by the pulse timing shown in FIG. 6. That is, in the first field, as shown in FIG. 6(a), φ5. φ6 is ○
While maintaining the FF state, φ1. φ2 and φ1. φ4 alternately repeats an on state and an off state every horizontal period. During the first horizontal video period, each color signal of Syu' from horizontal output $199, S2' from 100, S2' from 200, and / is read out. Sorted out,
S' is the output signal S, 82' is S2, S
, / are output as S3. On the other hand, in the next horizontal video period, horizontal output lines 200, 300, 40C1%
81' each.

The color signal of S2'fs,' is read out. Horizontal output line 2
The color signal 00 changes from S 31 to 51', but by passing through the circuit of FIG. 5, this color signal is output from S1 as in the previous horizontal video period. Also S,′.

S, / are also output as S, , S, respectively.

Similarly, in the first field, S 2/ is always S
As □, 82' is output as S, and as 83' and S are output. - In the force cylinder 2 field, as shown in Fig. 6(b), φ8. With φ4 kept in the off state, φ1. φ6 and φ2. The on state and off state of φ are alternately repeated. This allows the horizontal output, 1199 and 100 color signals to be output for interlace operation during the first horizontal video period.
, and remove it through the S process. Then, in the next horizontal video period, horizontal output lines 100, 200, 300 (711 signal S3
' t 8% IS , j respectively S, , S, , S1
Output from. Repeat the same operation below. When the distribution circuit shown in FIG. 5 is used in this way, the output signals 88 to S,
During one field period, the color signals output as always are the respective interval color signals S2'+S3' or S2'.

Since S3'ls*' is obtained, the switching circuit 601 as an external circuit becomes a simple circuit that switches S2 and 83 for each field, and the signal processing circuit can be simplified. Furthermore, since the color signal is always output through the same preamplifier during one field period, it is possible to obtain a high-quality image without line crawling caused by variations in the amplification factors of the preamplifiers.

7rM is a diagram showing another embodiment of the distribution circuit 9' of FIG. 4. The circuit shown in Figure 7 has automated driving by replacing some of the pulses used to drive the circuit shown in Figure 5 with vertical scanning line pulses, and a MOS switch that passes through the process of reading signal charges. This circuit differs from the circuit shown in FIG. 5 in that the number of MOS switches is reduced from two to one, thereby reducing the amount of noise increase due to the parasitic capacitance and on-resistance of the MOS switch. In other words, the circuit shown in Figure 7 is the first to perform vertical scanning! 10', while in the first field, φ1 is in the ON state and φ7 is in the ON state.
Keep it off. And MOS switch 70
1 is kept off, while MOS switch 7 is kept off.
02 can be directly controlled by vertical scanning line 1°. After that, when the vertical scanning lines 10 and 20 are turned on during the first horizontal retrace period, the color signal S,' of the horizontal output line 99 is turned on by the MOS switch 702 during the subsequent horizontal video period.
The color signal S of the horizontal output line 100 is output as the output signal S1, and the color signal S of the horizontal output line 200 is output as the output signal S2 through the MOS switch 703.
is outputted as an output signal S through -T-X (MOS) Similar to the video period, horizontal output, tI200 color signal 81'
is passed through a MOS switch 705 as Sl, the color signal S of the horizontal output line 300, 1 is output as S2, and the color signal S of the horizontal output line 400 is output as S3. On the other hand, in the second field, φ7 is kept on, φ is kept off, and the MOS switch 7
MOS switch 7 while keeping MOS switch 02 off.
01 allows direct control by the vertical scanning line 10. After that, during the first horizontal video period, the vertical scanning lines 10' and 10 are turned on, and the color signals of the horizontal output lines 99 and 100 are turned on (MOS).
MOS) through switches 706 and 701 to remove S, and 81, and in the next horizontal video period, vertical scanning line 2 is removed.
0 and 30 are turned on, the horizontal output and the color signal S of l1100 pass through the MOS switch 703,
As S2, the color signal 82' of the horizontal output line 200 passes through the MOS switch 704, and as S, the color signal S,' of the horizontal output line 300 passes through the MOS switch 707 and is output as Sl. . In this way, the color signals outputted as output signals 81 to S by the distribution circuit of FIG. 7 as well as the distribution circuit of FIG.
Each color signal 81' is always the same during the field period.

Sl'lS3' or S '' t S2' f L
' Therefore, the same effect as the circuit shown in FIG. 5 can be obtained.

FIG. 8 is a diagram showing yet another embodiment of the distribution circuit. This circuit is a modification of the circuit shown in Figure 5, in which φ1' and φ2' are alternately turned on and off for each horizontal video period while keeping φ3' and φ4' off in the first field. drive On the other hand, in the second field, φ1' and φ2' are kept in the off state, and φ3' and φ,' are alternately switched between the on state and the off state for each horizontal video period. As a result, the output signal 81~
S.

As, in the first field, S ′ to S, ′ are respectively in the second field.
811 to S,' are output in each field. Therefore, in this circuit, in addition to the same effect as in FIG.
Even the circuit for exchanging 2 and S for each field can be removed, simplifying the signal processing circuit.

FIG. 9 shows yet another distribution circuit, in which the same modification as the circuit in FIG. 8 with respect to FIG. 5 is added to the circuit in FIG. 7, and as in FIG. S
,/or 81' to S,' are output, and the signal processing circuit can be made simpler than the circuit shown in FIG.

FIG. 10 is a diagram showing a structural diagram of a solid-state imaging device according to another embodiment of the present invention. This element has a built-in color signal switching circuit 9' in the element output section of the element shown in FIG. FIG. 11 is a circuit diagram showing an embodiment of this switching circuit 9', in which pulses with the timing shown in FIG. 12 are input to the terminals φ,' to φ□',
The signals read out in step 301 are exchanged for each color signal and output. Therefore, the color signals output as the output signals 81 to S2 are always the same color signal S1 during one field period.
'tS2'tS2' Or S,'.

S2'ls,', so that the same effect as the element shown in FIG. 9 can be obtained.

〔Effect of the invention〕

As explained above, according to the present invention, the three independent color signals S' to S, and/or S' to S,' can always be output from the same terminal during one field, so that the output signals can be The external circuit that must be replaced every horizontal period becomes simple or unnecessary, and the signal processing circuit can be simplified.

Furthermore, even if the amplification factor of the preamplifier varies, line crawling does not occur and high-quality images can be obtained.

[Brief explanation of drawings]

FIG. 1 is a structural diagram of a conventional device, FIGS. 2 and 3 are diagrams showing the structure and signal processing circuit of an improved device, and FIGS. 4 to 9 are diagrams of a device showing an embodiment of the present invention. 10 to 12 are diagrams showing the structure and driving method of an element showing other embodiments of the present invention. Early I Circle Figure 2 Figure 3 Entrance 40 S, S'2 S3 Figure 6-BL Multiplication Table Number 7 Entrance q Entrance 9' Figure 70

Claims (1)

[Claims] 1. A pixel array consisting of a photoelectric conversion element and a switch element, and horizontal and vertical scanning circuits for sequentially selectively scanning the pixel array, wherein the switch element in the pixel is configured to perform the photoelectric conversion In a solid-state imaging device, two adjacent rows are connected in series, consisting of a switch element connected to the element and driven by a vertical scanning circuit, and a switch element connected to a horizontal output line and driven by the horizontal scanning circuit. The pixel column is connected to three horizontal output lines sandwiching the two pixel columns via the switch element, and the horizontal output line is connected to the three horizontal output lines during the horizontal video period of the television signal. 1. A solid-state imaging device having a structure in which three signal output lines are connected to each other via a distribution circuit having a function of selecting a horizontal output line. 2. In claim 1, the distribution circuit always connects the upper horizontal output line of the three horizontal output lines to the first signal output line during one field period of the television signal,
A solid-state imaging device characterized in that a middle horizontal output line is connected to a second signal output line, and a lower horizontal output line is connected to a third signal output line. 3. In claim 1, the distribution circuit connects the upper, middle, and lower three horizontal output lines to corresponding first, second, and
A solid-state imaging device characterized in that the correspondence relationship of connection to the third three signal output lines is changed every one field period of a television signal. 4. In claim 1, three signal output lines connected to the three horizontal output lines and a signal external to the element are provided through a circuit having a function of selecting the three horizontal output lines. is connected to the horizontal output line above the three horizontal output lines among the three signal output lines during one field period of the television signal. Connect the signal output line to the first output terminal, the signal output line connected to the middle horizontal output line to the second output terminal, and the signal output line connected to the lower horizontal output line to the third output terminal. A solid-state imaging device characterized by inserting a switching circuit.