JPS58139463A - Solid-state image pickup device - Google Patents

Abstract

PURPOSE:To omit a mechanical shutter in a solid-state image pickup device by reading out signal charges produced by the first and second groups of photodetectors aligned in horizontal and double series rows to a vertical transfer unit, transferring and storing the signals into a memory, and sequentially outputting them to a horizontal continuous transfer unit. CONSTITUTION:A voltage Vr is applied to a terminal r during a period tc to open a gate R, and excess charge is absorbed through a vertical transfer unit 3 to an absorber 5. Then, reverse phase pulse is applied to a terminal V for the time td to clean by a cleaner 5 the charge of the unit 3, the gate R is closed, the charge is stored for the period ts, a gate R1 is opened for tr1, the charges of the first field P1 group are read out, the R1 is closed for next tv1, positive transfer pulse psit is applied to the terminal V, pulse psi' is added to a terminal S, and stored in a memory 6. The memory 6 is not transferred for next tr2, the charge of P2 group of the second field is read out, the memory 6 is transferred to the memory 7 for the tv2, and stored in the memory 6. The transfer pulse of reverse phase is applied via a horizontal transfer unit 8 to a terminal (h) and to an output unit 9, the first and second field signals are sequentially obtained, and when the ts is selected, the adjustment for the mechanical shutter can be obtained by the similar effect.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a solid-state imaging device that has a solid-state imaging surface configured with a charge transfer element arranged thereon and that can obtain a still image imaging output signal without using a mechanical shutter mechanism. .

An imaging device having a solid-state imaging surface configured using a charge transfer element, for example, a charge-coupled device (hereinafter referred to as CCD), that is, a solid-state imaging device, has been made smaller and lighter, It has been put into practical use as a component of television cameras with low power consumption. There are several types of solid-state imaging devices, such as frame transfer type, interline transfer type, and hybrid transfer type. An imaging output signal is obtained by transferring signal charges obtained by photoelectric conversion to an output section in a predetermined order using the operation of a CCD.

When obtaining a still image imaging output signal with such a solid-state imaging device,
In other words, when configuring a so-called still camera,
A mechanical shutter that can be opened and closed is provided in front of the imaging surface. This mechanical shutter is normally closed and is opened for a short time only when taking an image. When it is closed, light is blocked from entering the imaging surface, and only when it is open, the imaging surface is blocked from entering the imaging surface. As a result, a signal charge corresponding to the incident light is obtained in the light receiving element. Then, the signal charges obtained in this manner are transferred, and an imaging signal based on the subject image at that time is obtained as a still image imaging output signal.

However, in conventional solid-state imaging devices that are equipped with such a mechanical shutter to obtain still image output, the shutter mechanism installed is complicated and expensive, and mechanical accuracy deteriorates after long-term use. This has caused various problems, such as the reliability of the shutter being reduced, and the shutter mechanism interfering with miniaturization of the entire Still camera.

In view of the above-mentioned problems, the present invention has been devised so that a still image pickup output signal can be obtained without providing a mechanical shutter, and the output signal is not subject to deterioration that causes smearing or blooming phenomena. The present invention provides a novel solid-state imaging device that has the following features. Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a schematic configuration of essential parts of an example of a solid-state imaging device according to the present invention. In FIG. 1, P/, P, and t are light receiving element portions, which are arranged in horizontal rows and vertical rows on the imaging surface. The light-receiving element portions P/ are the odd-numbered ones in each vertical column, and the light-receiving element portions P- are the even-numbered ones in each vertical column. When these light-receiving element parts Pl and P- receive incident light, they perform photoelectric conversion according to the incident light to generate charges, and accumulate charges as necessary.

A vertical transfer section 3 is arranged along each vertical column formed by the photodetector sections P/ and P-, and there is a gap between the photodetector section P/ and the vertical transfer section 3 and between the photodetector section PJ and the vertical transfer section 3. In between, read gate portions R/ and R,2 are formed, respectively.

These readout gate portions R/ and RJ function to read out the charges of the light receiving element portions P/ and PJ to the vertical transfer portion 3 when set to a predetermined potential. In addition, the vertical transfer section 3 is a CCD
According to the supplied drive signal, the charge from the light receiving element parts P/ and P2 is transferred along each vertical column formed by the light receiving element parts P/ and P,2, and the charge is Perform vertical transfer. A light receiving/vertical transfer section t is configured including the light receiving element section P/, Pmu readout gate section R/, Rmu vertical transfer section 3, etc.; Gate voltage terminals r/ and r,2 are derived for setting the parts R/ and Ry to predetermined potentials, and further, a vertical terminal for supplying a drive signal (for example, a two-phase drive signal) to the vertical transfer part 3 is derived. Drive signal terminals V/ and V2 are led out. On the - side of the light receiving/vertical transfer section μ, an absorbing section j to which one end of each vertical transfer section 3 is connected is disposed.

On the side opposite to the charge absorption part j side of the light receiving/vertical transfer part ≠, a first storage part B formed of a CCD group, which is adjacent to the other end of each vertical transfer part 3, is disposed. Adjacent to the first storage unit B, a second storage unit 7 is formed of the same CCD group.
are arranged. These first and second storage units 6 and 7
For example, drive signal terminals S/ and S2 + to which drive signals of different phases are supplied, and 1. and t, 2 are provided. Furthermore, a horizontal transfer section g is provided adjacent to the second storage section 7.
is arranged, and an output section is arranged at the end of this horizontal transfer section r. Horizontal drive signal terminals h/ and h for supplying a drive signal (for example, a λ-phase drive signal) are derived from the horizontal transfer section r, and a signal output terminal IO is derived from the output section. ing. The second and second storage units B and 7 transfer the charge transferred from the vertical transfer unit 3 to a predetermined storage position and store it in response to the supplied drive signal, and also store the stored charge. The horizontal transfer section g transfers the charge transferred from the second storage section 7 to the output section based on the supplied drive signal, and the horizontal transfer section g transfers the charge transferred from the second storage section 7 to the output section. horizontal transfer. The output section generates an imaging output signal corresponding to the charge transferred from the horizontal transfer section, and this is obtained at the signal output terminal 10.

Next, an explanation will be given of the operation when a still image imaging output signal is obtained by an example of the solid-state imaging device according to the present invention configured as described above. In this case, the light receiving/vertical transfer section≠
The gate voltage terminals r7 and r2 of the gate voltage terminals r7 and r2 are supplied with gate voltages vr/ and Vr2, respectively, and the vertical drive signal terminals V7 and V- are supplied with two-phase vertical drive signals φV/ and 2, respectively. 2 to the drive signal terminals S/ and S- of the memory section B.
Phase drive signals φ' and φλ' are supplied to the drive signal terminals 1. of the second storage section 7. The same two-phase drive signals sl' and φ-1 are selectively supplied to φh/ and φhJ are supplied.

First, in a period before still image capturing is performed, that is, in a standby period tc, as shown in FIGS. 2A and B, (
, gate voltages Vr/ and Vrλ are set to high level, thereby both read gate portions R/ and R- are brought into an open state. Therefore, the charges obtained in this staff (light receiving element part P in the Isuke space tc) and P,2 are
/ and R2 to the vertical transfer unit 3. Also,
At this time, as shown in FIGS. 2C and 2D, the vertical drive signals φV/ and φv,2 are in a steady state in which they assume constant high and low levels, respectively. Therefore, no transfer operation is performed in the vertical transfer section 3, and the vertical transfer section 3 serves as an overflow drain, and excess inflow charges are transmitted to the charge absorption section j and absorbed. Next, when still image capturing is started, in the initial period td, as shown in the second Jlh and D, the vertical drive signals φv and φVJ are, respectively,
The reverse transfer pulses ψdl- and .fd are used, and the vertical transfer section 3 transfers the charge at high speed to the charge absorption section j in the opposite direction to the first storage section t. As a result, a sweep transfer is performed in which the charge in the vertical transfer section 3 is swept out to the charge absorption section j, and unnecessary charges within the vertical transfer section 3 are swept away. At the same time, at the start of the initial period td, FIG.
As shown in FIGS. 1 and 2B, the gate voltages Vr1 and Vr are set to a low level, whereby both the read gate portions R/ and R are closed, and a light receiving period t begins. During the light receiving period ts, charges obtained according to the incident light are accumulated as signal charges in the light receiving element portions P/ and P-.

Note that the above-mentioned sweeping transfer may be performed over the entire light receiving period tS, and in that case, if an excess signal charge is generated during the light receiving period ts, it is drained to the vertical transfer section 3 and eliminated. You can do as you like.

Predetermined light reception period 1. When t ends, the first read period t
r, and during this period tr/, the gate voltage vr/ is set to a high level, as shown in FIG. 2A.

This opens the read gate section R/, and the signal charges accumulated in the light receiving element section P/ are read out to the vertical transfer section 3. At this time, the vertical drive signals φV/ and φVλ are in a steady state, and the vertical transfer section 3 does not perform a transfer operation.

The light-receiving element portion P/ is an odd-numbered one in each vertical column formed by the light-receiving element portions P/ and Pλ, and forms a group forming the first field signal of the video signal. , Therefore, during the first readout period tr/, the signal charges to form the first field signal are transferred to the vertical transfer section 3.
It will be read out. Continuation (first vertical transfer period t
In vl, the gate voltage Vrz is again the gate voltage Vr.
- is set to low level along with the read gate portions R/ and R.
− is considered a closed state. Then, during this period tvl, as shown in FIG.
As shown in FIGS. 4E and F, the drive signals φ/' and φco', which had been in a steady state until this period, are converted into transfer pulses v, j and data', and are transferred to the first storage section. It is supplied to drive signal terminal 111 and Sλ of B. As a result, the signal charges read into the vertical transfer section 3 in the first read period tr/ are transferred to the first storage section B through the vertical transfer operation of the vertical transfer section 3 and the transfer operation of the first storage section B. and stored in each horizontal column.

Next, a second read period tr,2 is entered, and this period tr
-, as shown in Figure λB, the gate voltage Vr, 2
is considered to be at a high level. As a result, the read gate section R,2
is opened, and the signal charge accumulated in the light receiving element section Pλ is read out to the vertical transfer section 3. At this time, the vertical drive signals φV/ and φVco and the drive signals φl' and -1' are both in a steady state, and the vertical transfer section 3 and the first storage section B do not perform a transfer operation.

The light-receiving element parts P are the even-numbered ones in each vertical column formed by the light-receiving element parts P/ and P, 2, and form a group that forms the second field signal of the video signal. Therefore, in the second read period tr,
Signal charges to create a second field signal are read out to the vertical transfer section.

During the subsequent second vertical transfer period tv, the gate voltage Vr2
is again set to a low level along with the gate voltage Vr1, and the read gate portions R- and R1 are closed. During this period tv, as shown in FIG.
and ft2, and the drive signals -/' and ≠-' are again transferred to the transfer pulse ψ
l' and ψ-', and the drive signal terminals S/ and 8 of the first storage unit B and the drive signal terminals 1 and 8 of the second storage unit 7 are connected to each other. and t, 2. As a result, the signal charges stored in the first storage section B are transferred at high speed to the second storage section 7 by the transfer operations of the first and second storage sections B and 7, and the signal charges are transferred to the second storage section 7 in each horizontal column. The signal charge stored in the vertical transfer unit 3 and read out in the second read period trλ is transferred to the first memory by the vertical transfer operation of the vertical transfer unit 3 and the transfer operation of the first storage unit B. Transferred at high speed to part 6,
stored in each horizontal row.

Due to the above operation, during the light receiving period ts, the light receiving element portion P
The signal charges obtained in / are temporarily stored in the second storage section 7 as signal charges to generate the first field signal, and are also obtained in the light receiving element section P, 2 during the light receiving period t8. The generated signal charge is temporarily stored in the first storage part B as a signal charge to generate a second field signal.

Then, in the period after the second vertical transfer period tvJ, the gate voltages Vr/ and Vr4 and the vertical drive signals -V/ and φv
, 2 are each in the same steady state as the standby period tc described above. On the other hand, the drive signals φl' and -ko' each have a period of the /horizontal period of the video signal, and have a width equal to or less than the width corresponding to the horizontal blanking period, and are pulses (not shown) in opposite phases to each other. The drive signal terminals 81 and S of the first and second storage units B and 7 and 1. The signal charges temporarily stored in the second and first storage units 7 and B are supplied to the storage units 7 and 6 for each period corresponding to each horizontal blanking period. Column by column, sequentially.
It is transferred to the horizontal transfer section g. Horizontal drive signals φh/ and φh,2, which are high-frequency transfer pulses (not shown) with mutually opposite phases, are supplied to the horizontal transfer section g, and the horizontal drive signals φh/ and φh,2 are supplied to the second and first storage sections 7 and The signal charges of both storage units 7 and each horizontal column of B transferred from B to the horizontal transfer unit g are transferred to the output unit T during a period corresponding to each horizontal transmission period, and the signal charges of the first field and the first field are transferred to the signal output terminal 10. Two fields of signals are obtained sequentially.

This signal is based on the light incident on the light receiving/vertical transfer section t during the light receiving period ts described above (2 fields, i.e.,
/ frame signal, and by selecting an appropriate light reception period tIll, it becomes a / frame still image imaging output signal. In addition, in the above description, the light receiving element portion Pλ
The signal charges read out from the light-receiving element section P/ have been accumulated for a longer period of time in the first readout period tr/ and the first vertical transfer period tv, compared to the signal charges read out from the light-receiving element section P/. Since the periods tr/ and tv/ are extremely short, they do not have a substantial adverse effect.

In this way, if a still image imaging output signal is obtained and the length of the light reception period ts is adjusted, the same effect as shutter speed adjustment when a mechanical shutter mechanism is used can be obtained.

As explained above, according to the solid-state imaging device according to the present invention, a still image imaging output signal can be obtained without using a mechanical shutter, and various problems caused by the shutter mechanism in still cameras can be solved. be able to. Further, the still image imaging output signal obtained by the solid-state imaging device according to the present invention is a first field signal and a second field signal created by reading out signal charges obtained in a large number of light receiving element sections using a field interlace method. Since it is formed by a signal, it has a high degree of vertical dissolution. Further, the signal charges that make up the signals of the first field and the second field are read out from the light receiving element section to the vertical transfer section, and then transferred at high speed to the storage section and stored in the storage section,
Furthermore, during the accumulation and transfer of these necessary signal charges, unnecessary charges and excess charges are removed through the vertical transfer section, so that deterioration appearing as smearing or pluming phenomena is extremely reduced.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing the main parts of an example of a solid-state imaging device according to the present invention, and FIG. 2 is used to explain the operation when a still image pickup output signal is obtained by the example shown in FIG. FIG. In the figure, P/ and P- are light receiving element parts, R/ and Rco are reading gate parts, 3 is a vertical transfer part, ≠ is a light receiving/vertical transfer part,
j is a charge absorption section, B is a first storage section, 7 is a second storage section, ♂ is a horizontal transfer section, D is an output section, and 10 is a signal output terminal. 1st II 1 n2

Claims (1)

[Claims] After signal charges are accumulated by light reception for a predetermined period in a plurality of light receiving elements arranged in horizontal rows and vertical rows, a first group of the light receiving elements is formed. The signal charge obtained by the light receiving element is read out and transferred to the vertical transfer section extending along the vertical column of the light receiving elements, and is transferred to the first storage section via the first storage section adjacent to the vertical transfer section. Signal charges temporarily stored in a second storage section adjacent to the light-receiving elements and obtained by a second group of the light-receiving elements are separately read out and transferred to the vertical transfer section;
The signal charges temporarily stored in the first storage section and temporarily stored in the second and first storage sections are sequentially transferred to the horizontal transfer section, and transferred to the output section by the horizontal transfer section. A solid-state imaging device that is configured to obtain an imaging output signal.