JPS6249653A - Charge transfer device - Google Patents

Abstract

PURPOSE:To improve the transfer efficiency as well as to stabilize the quantity of signal charge of the titled device by a method wherein a plurality of the second transfer electrodes, the switching of which is controlled independently, are provided adjoining the different side of the first transfer electrodes with which the signal charge sent from a charge transfer part is transferred. CONSTITUTION:The signal charge of each color photoelectrically converted by a two-dimensionally arranged photosensitive part Pij passes through a vertical read-out resistor Ci, then passes through a horizontal read-out resistor H, and is sent to a signal separation resistor S. The signal separation resistor S has as many branch-transfer electrodes, which are exclusively used for branching of signal charge, as are required for branching the signal charge, and a transfer electrode in the former stage of the transfer electrode are used commonly. The pulse exclusively used for signal separation is applied to the gates SGR, SGG and SGB of each branch-transfer electrode.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a charge transfer section that is continuously arranged on a semiconductor substrate and is capable of branching signal charges.

[Technical background of the invention and its problems]

Solid-state image sensors are beginning to be used in home color video cameras. One of the desirable conditions for a color video camera for home use is a reduction in size and price. Therefore, by incorporating the color separation L path portion of the signal processing circuit into the element, the number of electrical components can be reduced. Therefore, cameras can be made smaller and cheaper.

FIG. 6 is a conventional configuration diagram in which a color separation circuit is incorporated into an interline transfer type COD.

Pij (”'1s 2,...* M, J=l+ 2
,..., N) is a two-dimensional array of photosensitive parts, and the photosensitive parts are striped color filters that are all the same color in the vertical direction so that the R, G, and B blue signals can be branched. is formed.

Further, Ci is a vertical read register, H is a horizontal read register, and S is a signal branch register.

Signal charges R and G of each color photoelectrically converted in the photosensitive area
SB passes through the vertical read register Ci, passes through the horizontal read register H, and passes through the signal branch register S to 几 and GS, respectively.
After being separated into the B signal, the charge of the signal ' is detected by the normal floating diffusion amplifier (FD) method, and is outputted to the output terminal by the output amplifiers AR, G and AB.

Vertical read register Ci has φv1, φv2, φ■1, φ
(4) 4-phase drive consisting of 4 transfer electrodes is performed.

The horizontal read register H performs two-phase driving of φH8 and φH.

FIG. 7 shows a timing chart and branched output signals. The horizontal read pulses φH1 and φ) are mutually inverted two-phase pulses, and the signal branch pulse SG has a period of 1/3 of the horizontal read pulses φH, φ)i. The reset gate pulse KG is a pulse having the same phase as the horizontal transfer pulse φH1. First, at 11 o'clock, from horizontal CCD register H,
The color signals of RlGSB are branched into one set of signals and read out to the register S.

At time t, the SG pulse becomes H level and is transferred to each register. 1. At this time, φH81! of the signal branch register S which is the next transfer electrode! The respective signals are transferred to the poles. At 14 o'clock, the ordinary signal charge passes through the output gate OG and enters the floating diffusion F.
A signal charge is detected by D and outputted from output terminal 08R by output amplifier AR. Similarly, the G signal charge and the B signal charge are transferred sequentially, and the G signal is at t6, and the ordinary signal is at t6.
, output from each terminal O8G, O8B at the time.

This structure has the drawback that the color filter arrangement is limited to stripe-type filters of three color sets, and cannot be applied to mosaic-type filters. Further, since the signal separation register is provided, the number of transfer stages increases, and the length of the transfer path increases, resulting in deterioration of transfer efficiency.

Furthermore, since the G signal and B signal registers are branched in the signal separation register, the G signal charge is left behind at the B signal branch point, and the signal amount decreases. Further, in the case of ordinary signal charges, charges are left behind at the branch points of the B signal and the branch points of the G signal, and the signal amount further decreases. Conversely, the B signal charge increases because the G signal charge left behind and the ordinary signal charge are added. For this reason, there was a drawback that the color reproducibility of 'R and GSB deteriorated.

[Purpose of the invention]

It is an object of the present invention to improve the transfer efficiency, which has been a drawback of the prior art, to stabilize the amount of signal charge, and to provide a signal branching register to which a mosaic type filter can be applied.

[Summary of the invention]

The present invention provides a solid-state image pickup device having a photosensitive section in which photosensitive pixels are arranged in a -dimensional or two-dimensional manner, and a signal charge transfer section, in which the transfer register has a structure for branching signal charges. This signal branch register has branch transfer electrodes dedicated to the number of branches, and the transfer electrodes at the stage before the branch gates are common. The register is a signal branch register that can branch signal charges by applying branch gate pulses corresponding to the arrangement of color filters in the photosensitive section.

〔Effect of the invention〕

By applying the present invention, the transfer efficiency, which was a problem in the past, has been improved, and by stably obtaining the amount of charge for each color signal, it is possible to transfer minute signal charges, so even if the amount of incident light is small, it can be output. You can create a camera that takes pictures. or,
Since it is possible to freely select color filters using one type of device, it is possible to make the system more effective for each user, and furthermore, it is possible to easily consider various color filters.

[Embodiments of the invention]

FIG. 1 shows an example in which the present invention is implemented in an interline transfer type COD of R-red, 0-ring, and B (to) striped color filters.

Pij (i=1.2,..., M, j=1.2,...
・N) is a two-dimensional array of photosensitive parts, R of the photosensitive parts is a red signal, G is a green signal, and B is a striped color filter for photoelectrically converting a blue signal. and,
Ci is a vertical read register, H is a horizontal read register and S is a signal separation register.

Signal charges R and S of each color photoelectrically converted in the photosensitive part
o, B pass through the vertical read register Ci, pass through the horizontal read register H, and pass through the signal separation register S to R, , , respectively.
The signals are separated into G and B signals and outputted to output terminals by output amplifiers AR, A, and AB.

Vertical read register Ci is φ■1, φv1, φ■8, φ
Consists of 4 transfer electrodes of v4. Four-phase driving is performed, and horizontal read register H performs two-phase driving, φH1 and φH2. Further, pulses 8()R, 80G, and 8GB dedicated for signal separation are applied to the signal separation register S.

FIG. 2 shows the pulse and the separated output signal.

The horizontal read pulses φH1 and φH8 are mutually inverted two-phase pulses, and are signal separation pulses 5GRSSGG.

8GB is horizontal read pulse φH1, 1/1 of φH1.
In three cycles, 5GRS8GGSSGB applies pulses with different phases by 60'. The reset gate pulse KG is applied to the output terminal 08 of the output amplifier by applying a pulse having the same period as the horizontal readout pulse φH1.
R, G from R, 08G, O8B, respectively.

The output signal is separated into the B signal and has a phase of 600 J%.

In the present invention, the signal separation register S is provided with gates 8GR, 8GGS, and 8GB dedicated to signal separation, and the gates before separation are made common, thereby eliminating the need for a dummy transfer register for phase matching in the signal separation register S. Furthermore, since the signals are not separated in the middle of the transfer register, RlG and B color signals with high transfer efficiency can be obtained.

FIG. 3 shows an example in which a mosaic color filter is implemented in an interline transfer type COD.

Since everything except the color filters has the same structure as in FIG. 1, the explanation will be omitted.

FIG. 4 shows the signal separation pulses 8GR, SGa, SGB and output signals.

The signal separation pulse SGG is the horizontal transfer pulse φH1, φH
The pulse of 1/2 period, 8GR pulse and SGB pulse, the presence or absence of the pulse is switched every 1 horizontal period ◎The period is SG
It is the same as the a pulse, but the phase is 180° different. These three signal separation pulses 8GGS8G:R.

By applying 8GE, the color signals of the mosaic color filter, which could not be separated using the conventional method, can be separated. In this way, signal separation/pulse 80R, SGG regardless of the color filter arrangement.

It has the advantage that all color filter arrays can be separated by using 8GB as a pulse that matches the color filter array.

Other application examples will be explained using FIG.

For example, by setting the frequency band characteristics of the output amplifiers A1, Person 1, and A to different values, different frequency band characteristics can be selected by selecting the branch game (SG).

Also, by setting the gains of the output amplifiers A, , A, , A to different values, different gains can be selected depending on the selection of the limb game) 8G. or,
There is no limit to the number of branches.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of an embodiment of the present invention, Fig. 2 is a timing chart and output signal diagram for explaining its operation, Fig. 3 is a block diagram of an application example of the present invention, and Fig. 4 is its A timing chart and an output signal diagram to explain the operation, Figure 5 is a configuration diagram to explain other application examples, Figure 6 is a conventional configuration diagram, and Figure 7 is its timing chart and output signal diagram. be. In the figure, S...Signal branch register, H...Horizontal read register, OG...Output gate, FD...Cloating diffusion, 8 Git, 5 (3G, SGB, SG1, SG, ,SG
, , SG... Signal limb gate, ARSAeSAB, A, , A, , A,... Output amplifier, φH1, φH1... Horizontal read register transfer pulse 1o 81% OS 0% 08 B s o
ss, o S2, O8, H... Signal output terminal of COD, R...Red signal, G...Green signal, B...Blue signal. Agent Patent Attorney Nori Ken Yudo Takehana Kikuo O19SGm Figure 1 O19St; B Figure 3

Claims (1)

[Claims] A charge transfer section and a signal branch section connected to the charge transfer section are provided on a semiconductor substrate, and the signal branch section includes a first transfer electrode that transfers signal charges from the charge transfer section, and a first transfer electrode that transfers signal charges from the charge transfer section. A charge transfer device comprising a plurality of second transfer electrodes adjacent to each side and whose opening and closing are independently controlled.