JPS62232157A - Image sensor - Google Patents

Abstract

PURPOSE:To improve sensitivity and resolution and to implement high density, by alternately arranging a plurality of light receiving elements and vertical transfer CCDs, which are aligned along the direction of a column, injecting signal charge in a substrate by pairs of MOS electrodes, which are scanned by a horizontal transfer control part, and reading the charge. CONSTITUTION:Signal charge, which is stored in a light receiving part 1, is simultaneously transferred to a vertical transfer CCD as the total picture elements during a part of a vertical blanking period. The signal charge, which is moved to the vertical transfer CCD, is sent to pairs of MOS electrodes 3 at the standard scanning speed of television. At this time, a signal for one scanning in the vertical direction is sequentially transferred downward in parallel with other signals. At the same time when a gate electrode 9 is cut OFF, only an electrode 31, in which the signal charge is stored, is set at an L level. The signal charge is moved to a part beneath another electrode 32. When the electrodes 32 are sequentially scanned by a horizontal shift register 5, the charge is injected in a substrate 6. The charge is taken out as a video signal in one horizontal direction through a circuit 8.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an image sensor. To be more detailed,
The well-known CI D (Charge 1 injection
The present invention relates to an image sensor that can compensate for the shortcomings of conventional devices, provide high sensitivity, and can be integrated at high density.

(Conventional technology) Conventionally, as an area image sensor, X-Y
Addressing method CI D-? I L T (1nter
1inetransfer) method CCD or F'T
CCD is known.

CID basically consists of a matrix of X-Y addresses with MO8tm pole pairs close to each intersection, and
An image charge proportional to the incident light beam is accumulated in the inversion layer under the selection electrode of ing.

(Problems to be solved by the invention) However, in the conventional CID, the light receiving part and the charge injection part are formed in the same way, and the element surface is covered with void IJSi, so the sensitivity is low due to the light transmittance. Poor sensitivity, especially for blue, limited overall sensitivity. In addition, the recombination process in which photocharges are injected into the substrate requires tens to hundreds of tons.
rsJ degrees, and therefore, the continuously generated charges diffused to adjacent pixels, causing a lot of crosstalk. On the other hand, in the ILT method, increasing the number of horizontal pixels puts a limit on high frequency drive, so for example, dual-hand channel CCD
Therefore, methods such as allocating charges and reading them were devised. However, this method has the disadvantage that charge allocation becomes complicated.

An object of the present invention is to provide an image sensor that can improve sensitivity, increase horizontal resolution, and achieve high density. The above purpose is to have multiple photodetectors arranged along the column direction and vertical transfer CCDs arranged alternately, and to the output side of the vertical transfer CCDs, a scanning MO8 electrode pairs are arranged horizontally corresponding to each element column, and signal charges are
A pair of O8 electrodes is injected into the substrate and read out by the image sensor.

(Embodiment) An embodiment of the image sensor according to the present invention will be explained in detail below based on the drawings. In one embodiment shown in FIG. ) has the same structure. In other words, it has a structure in which a light receiving section consisting of a plurality of light receiving elements arranged along a column direction and a vertical transfer CCD are arranged alternately, and the vertical transfer CCD
D is driven in four phases. In the figure, the light receiving section 1 and the vertical transfer section 2 are shown as simplified blocks.

At the output end of the vertical CCD, there is an M extending along the horizontal direction.
An O8 electrode pair 3 is arranged. The MO8 electrode pair 3 includes a polysilicon electrode 31 common to each pixel column and @l1r
ii Each pixel column is composed of an independent polysilicon electrode 32, and the independent electrode 32 for each pixel column is further connected to a horizontal shift register 5 via an aluminum wire 4. A readout circuit 8 including an amplifier 7 is provided.

FIG. 2 shows an enlarged view of the vicinity of the MOS pole pair 3, that is, the MO81JL pole pair 3 is arranged on the output side of the vertical transfer section 2 via the gate electrode 9.

Further, the portion indicated by the symbol IO in the figure is the transfer rItfi! of the vertical transfer section 2! When the image sensor is configured like a rectangular shape and each pixel row is separated from each other by a channel stone 11, an image of the subject is formed on the light receiving part 1, In order to obtain a charge corresponding to the brightness of the subject, all signal charges accumulated in the light receiving section 1 should be transferred to the @direct transfer CCD all at once during a part of the vertical blanking period.

Note that the vertical transfer CCD is shielded from light so as not to be sensitive to incident light, as in the conventional case, and is configured to prevent light from mixing during vertical transfer. Vertical transfer CCDKThe signal charge moved is 1 vertically at the standard scanning speed of television.
The signals for the scanning lines are sequentially transferred downward in parallel, and the MO
81! Sent to pole pair 3. At this time, the gate electrode 9 is provided in a conductive state, and the MO8m0
8 electrode pairs, one electrode 31 with signal charge offset by level Kv
is accumulated in the potential well below. Then, when the gate electrode 9 is cut off, only the electrode 31 that has accumulated signal charges is set to the L level, and the signal charges are moved to the bottom of the electrode 32. Under such a state, when the m1Fi32 is sequentially scanned by the horizontal shift register 5, charges are injected into the substrate 6, and a corresponding current is detected via the readout circuit 8. When the horizontal scanning, which is taken out as a horizontal video signal, is completed, the MO8''W1 pole pair 3 is again set at H level and the signal charge from the vertical transfer CCD is sent.
Next, the signal charge is moved under one electrode as before, and then injected into the substrate and read out.

FIG. 3 is a diagram showing drive waveforms and video output signals for each electrode for realizing the above steps, in which one electrode 32 of the MO8 electrode pair is sequentially activated by a scanning signal during a horizontal scanning period. The figure shows how the charge is output.

Note that although the above embodiment uses a normally used continuously scanned horizontal shift register, an alternative KW
Of course, it is also possible to read out data in a random order using a suitable decoder. (Effects of the Invention) As described above, according to the image sensor of the present invention, unlike the conventional CID, the light receiving part is used as a normal ILCCD.
Since it has the same configuration as the 41JSl and does not place 41JSl on the light receiving section, it is possible to improve the blue sensitivity and improve the color imaging device.
There is also a great deal of freedom in chair design.

Further, since it is similarly constructed of an ILCCD, each pixel column is separated by a channel stone A, and the charge is transferred to the gate electrode 32 via the gate electrode 32 and then injected into the substrate, vertical crosstalk does not occur. Furthermore, horizontal transfer C
Since a CD is not used, the drive frequency and transfer efficiency limits imposed by the horizontal transfer section can be relaxed, pixels can be integrated at high density in the horizontal direction, and horizontal resolution can be improved.

[Brief explanation of drawings]

FIG. 1 is a diagram conceptually showing an image sensor according to an embodiment of the present invention, FIG. 2 is an enlarged view of the main part of diagram s1, and FIG. 3 is a diagram for explaining the operation. . 1... Light receiving section, 2... Vertical transfer section, 3... MO8
! l Pole pair, 4... Aluminum wire, 5... Horizontal shift lever.
transistor, 6...substrate, 7...amplifier, 8...readout circuit, 9...gate electrode, 10...transfer electrode,
11...Channel stopper (ρ12 person J Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] A plurality of light receiving elements arranged along the column direction and vertical transfer CCDs are arranged alternately, and the vertical transfer CCDs
An image sensor characterized in that a pair of MOS electrodes, which are scanned by a horizontal transfer control section through a gate electrode, are arranged in the horizontal direction on the output side of the sensor corresponding to each element column.