JPH0546150B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a solid-state imaging device having a solid-state imaging surface configured with a charge transfer element arranged thereon, and capable of obtaining a still image imaging output signal without using a mechanical shutter mechanism.

Imaging devices that have a solid-state imaging surface configured using a charge transfer device, such as a charge-coupled device (hereinafter referred to as a CCD), are becoming smaller, lighter, and less expensive. It has been put into practical use as a component of television cameras that consume less power. There are several types of solid-state imaging devices, such as frame transfer type, interline transfer type, and hybrid transfer type. By transferring the signal charges obtained by Tozuku photoelectric conversion to the output section in a predetermined order using CCD operation,
An imaging output signal is obtained.

When obtaining a still image output signal using such a solid-state imaging device, that is, 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 in the closed state, incident light to the imaging surface is blocked, and only when it is in the open state, the imaging surface is blocked from incident light. 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 and can output still images, the shutter mechanism installed is complicated and expensive, and the mechanical accuracy deteriorates after long-term use. The reliability of the shutter decreases.
The shutter mechanism caused various problems, such as hindering the miniaturization of the entire still camera.

In view of the above-mentioned problems, the present invention is designed to obtain a still image imaging output signal without providing a mechanical shutter, and furthermore, the output signal is not subject to deterioration that causes smearing or blooming phenomena. In addition, a novel solid-state imaging device is provided. 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 Figure 1, P ₁ and
_P2 is a light receiving element section, which is arranged in horizontal rows and vertical rows on the imaging surface. The light receiving element portion _P1 is the odd numbered one in each vertical column,
The light receiving element portion _P2 is an even numbered one in each vertical column. When these light receiving element parts P ₁ and P ₂ 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 disposed along each vertical column formed by the light receiving element sections _P1 and _P2 , and the light receiving element section
A read gate section is provided between P ₁ and the vertical transfer section 3 and between the light receiving element section P ₂ and the vertical transfer section 3, respectively.
R ₁ and R ₂ are formed. These readout gate portions R ₁ and R ₂ function to read out the charges in the light receiving element portions P ₁ and P ₂ to the vertical transfer portion 3 when set to a predetermined potential. Further, the vertical transfer section 3 is formed of a group of CCDs, and according to the supplied drive signal, charges from the light receiving element sections _P1 and _P2 are transferred to each vertical column formed by the light receiving element sections _P1 and _P2 . forward along,
Performs vertical charge transfer. These, light receiving element part P ₁
A light receiving/vertical transfer section 4 is configured including P ₂ , read gate sections R ₁ and R ₂ , vertical transfer section 3, etc. From this light receiving/vertical transfer section 4, read gate sections R ₁ and R Gate voltage terminals r ₁ and r ₂ are derived to set _V.2 to a predetermined potential, and a vertical drive signal terminal v ₁ is further provided to supply a drive signal (for example, a two-phase drive signal) to the vertical transfer section 3. and v ₂ have been derived. A charge absorption section 5 to which one end of each vertical transfer section 3 is connected is disposed on one side of the light receiving/vertical transfer section 4 .

On the opposite side of the light receiving/vertical transfer section 4 from the charge absorption section 5 side, there is a CCD adjacent to the other end of each vertical transfer section 3.
A first storage section 6 formed by a group of CCDs is arranged, and a second storage section 7, also formed by a group of CCDs, is arranged adjacent to the first storage section 6.
These first and second storage units 6 and 7 each have a drive signal terminal s ₁ to which a two-phase drive signal is supplied, for example.
and s ₂ , and t ₁ and t ₂ are provided. Further, a horizontal transfer section 8 is arranged adjacent to the second storage section 7, and an output section 9 is arranged at the end of this horizontal transfer section 8. Horizontal drive signal terminals h ₁ and h ₂ for supplying drive signals (for example, two-phase drive signals) are led out from the horizontal transfer section 8 , and a signal output terminal 10 is led out from the output section 9 . ing. The first and second storage units 6 and 7 transfer and store the charges transferred from the vertical transfer unit 3 to a predetermined storage position based on the supplied drive signal, and also store the stored charges. The horizontal transfer unit 8 transfers the charge transferred from the second storage unit 7 to the output unit 9 based on the supplied drive signal, and the horizontal transfer unit 8 transfers the charge transferred from the second storage unit 7 to the output unit 9. horizontal transfer.
The output section 9 generates an imaging output signal corresponding to the charge transferred from the horizontal transfer section 8, 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 gate voltage terminals _r1 and
r ₂ has gate voltages Vr ₁ and Vr ₂ , respectively, and
Two-phase vertical drive signals φv _{1 and φv 2 are supplied to the vertical drive signal terminals v 1 and} v ₂ , and two-phase drive signals φ ₁ are supplied to the drive signal terminals s ₁ and s ₂ of the first storage section ₆ . ' and φ ₂ ' are supplied to the drive signal terminal of the second storage section 7.
Similarly, two-phase drive signals φ ₁ ′ and φ ₂ ′ are selectively supplied to t ₁ and t ₂ , and furthermore, the horizontal transfer unit 8
Two-phase horizontal drive signals φ _h1 and φ _h2 are supplied to horizontal drive signal terminals h ₁ and h ₂ of .

First, a period before still image capturing is performed, that is,
During the standby period _tc , as _shown in _{FIG .}
Both _R2 are left open. Therefore, the charges obtained in the light receiving element sections P ₁ and P ₂ during this standby period t _c are drained to the vertical transfer section 3 via the read gate sections R ₁ and R ₂ . Also, at this time, Fig. 2C
and vertical drive signals φ _v1 and φ _v2 as shown in FIG.
are assumed to be in a steady state with 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 charges flowing in are transmitted to the charge absorption section 5 and absorbed. Next, when still image capturing is started, in the initial period _td , the vertical drive signals _φv1 and _φv2 are converted into reverse transfer pulses _d1 and _d2 , respectively, as shown in FIG. 2C and D. ,
Based on this, the vertical transfer section 3 transfers the charge at high speed to the charge absorption section 5 in the opposite direction to the first storage section 6. 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 5,
Unnecessary charges within the vertical transfer section 3 are wiped out. At the same time, at the start of the initial period t _d , A and B in Figure 2
As shown in FIG. 2, the gate voltages V _r1 and V _r2 are set to a low level, whereby both the read gate sections R ₁ and R ₂ are closed, and the light receiving period t _s begins.
During the light-receiving period _ts , the light-receiving element portions _P1 and _P2 are
Charges obtained in response to incident light are accumulated as signal charges. 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 , this is caused to flow out to the vertical transfer section 3. It is possible to exclude the

When the predetermined light reception period _ts ends, a first readout period _tr1 begins, and during this period _tr1 , the gate voltage _Vr1 is set to a high level, as shown in FIG. 2A. As a result, the read gate section _R1 is opened, and
The signal charges accumulated in the light receiving element section _P1 are read out to the vertical transfer section 3. At this time, the vertical drive signals φ _v1 and φ _v2 are in a steady state, and the vertical transfer section 3 does not perform a transfer operation. The light-receiving element portion _P1 is an odd-numbered one in each vertical column formed by the light-receiving element portions _P1 and _P2 , and forms a group forming the first field signal of the video signal. Therefore, during the first read period t _r1 , the signal charge that should form the signal of the first field is read out to the vertical transfer section 3 . In the following first vertical transfer period t _v1 , the gate voltage V _r1 and the gate voltage V _r2 are again brought to a low level, and the read gate sections R ₁ and R ₂ are closed. During _this period t _v1 , as _shown in _{FIG .}
Also, as shown in Figure 2 E and F,
The drive signals φ ₁ ′ and φ ₂ ′, which were in a steady state until this period, are converted into transfer pulses ₁ ′ and ₂ ′ and are supplied to the drive signal terminals s ₁ and s ₂ of the first storage section 6. be done. As a result, the signal charge read out to the vertical transfer section 3 in the first read period t _r1 is transferred to the first storage section 6 by the vertical transfer operation of the vertical transfer section 3 and the transfer operation of the first storage section 6. High-speed transfer to
stored in each horizontal row.

Next, a second read period t _r2 is entered, and this period
At t _r2 , as shown in Figure 2B, the gate voltage
V _r2 is considered to be a high level. As a result, the read gate section R ₂ is opened, and the signal charges accumulated in the light receiving element section P ₂ are read out to the vertical transfer section 3 .
At this time, the vertical drive signals φ _v1 and φ _v2 and the drive signals φ ₁ ' and φ ₂ ' are all in a steady state, and the vertical transfer section 3 and the first storage section 6 do not perform a transfer operation. The light-receiving element portion _P2 is an even-numbered one in each vertical column formed by the light-receiving element portions _P1 and _P2 , and forms a group forming a second field signal in the video signal. Therefore, in the second read period t _r2 , the signal charges to form the signal of the second field are read out to the vertical transfer section. In the subsequent second vertical transfer period t _v2 , the gate voltage V _{r2 and} the gate voltage V _r1 are again brought to a low level, and the read gate sections R ₂ and R ₁ are closed. _{During this} period t _v2 , as _shown in _FIG .
As shown in Figures E and F, the drive signals φ ₁ ′ and φ ₂ ′ are again converted into transfer pulses ₁ ′ and ₂ ′,
It is supplied to both drive signal terminals s ₁ and s ₂ of the first storage section 6 and drive signal terminals t ₁ and t ₂ of the second storage section 7 . As a result, the signal charges stored in the first storage section 6 are transferred at high speed to the second storage section 7 by the transfer operations of the first and second storage sections 6 and 7, and the signal charges are transferred to the second storage section 7 in each horizontal column. The signal charges stored in the vertical transfer section 3 and read out in the second read period t _r2 are transferred to the first storage section 3 through the vertical transfer operation of the vertical transfer section 3 and the transfer operation of the first storage section 6. The data are transferred at high speed to the storage unit 6 and stored in each horizontal column thereof.

Through the above operation, the signal charge obtained in the light receiving element portion _P1 during the light receiving period _ts is temporarily stored in the second storage portion 7 as a signal charge to generate a signal of the first field, Further, the signal charge obtained in the light receiving element portion _P2 during the light receiving period _ts is temporarily stored in the first storage portion 6 as the signal charge to generate the signal of the second field.

Then, in the period after the second vertical transfer period t _v2 ,
Gate voltages V _r1 and V _r2 and vertical drive signals φ _v1 and φ _v2
are respectively assumed to be in the same steady state as the standby period t _c described above. On the other hand, the drive signals φ ₁ ′ and φ ₂ ′ are
Each of the pulses has a period of one horizontal period of the video signal, has a width equal to or less than the width corresponding to the horizontal blanking period, and has opposite phases to each other (not shown).
Drive signal terminal s ₁ of first and second storage units 6 and 7
and s ₂ , and the signal charges supplied to t ₁ and t ₂ and temporarily stored in the second and first storage units 7 and 6 are both stored in each period corresponding to each horizontal blanking period. Each horizontal column of the storage units 7 and 6 is sequentially transferred to the horizontal transfer unit 8. And horizontal transfer section 8
Horizontal drive signal terminals _{h1 and h2} provided in the second and _second The signal charges of each horizontal column of both storage units 7 and 6 transferred from one storage unit 7 and 6 to horizontal transfer unit 8 are transferred to output unit 9 during a period corresponding to each horizontal video period.
The signals of the first field and the second field are sequentially obtained at the signal output terminal 10.
This signal is transmitted during the light reception period _ts mentioned above.
It is a signal of two fields, that is, one frame, based on the light incident on the vertical transfer unit 4, and the light reception period is
By selecting an appropriate length of t _s , a one-frame still image imaging output signal is obtained. In addition, in the above, the signal charge read out from the light receiving element part _P2 is compared with the signal charge read out from the light receiving element part _P1 in the first readout period t _r1 and the first vertical transfer period t _v1. However, it has been accumulated over a long period of time.
Since these periods t _r1 and t _v1 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 pickup output signal can be obtained without using a mechanical shutter, and a still image pickup output signal can be obtained without using a mechanical shutter.
Various problems caused by the shutter mechanism in cameras can be solved. 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, which are generated by reading signal charges obtained from a large number of light receiving element sections using a field interlacing method. Since it is formed by a signal, the vertical resolution is high. Further, the signal charges that create 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. During accumulation and transfer of signal charges, unnecessary charges and excess charges are removed through the vertical transfer section, so that deterioration appearing as smear phenomenon or blooming phenomenon is extremely reduced.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing a main part 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 imaging output signal is obtained by the example shown in FIG. 1. FIG. In the figure, P ₁ and P ₂ are light receiving element parts, R ₁ and R ₂ are readout gate parts, r ₁ and r ₂ are gate voltage terminals, v ₁ and v ₂ are vertical drive signal terminals, s ₁ , s ₂ , t ₁ and t ₂ are drive signal terminals, h ₁ and h ₂ are horizontal drive signal terminals, 3 is a vertical transfer section, 4 is a light receiving/vertical transfer section, 5 is a charge absorption section, 6 is a first storage section, 7 is the second memory section, 8
9 is a horizontal transfer section, 9 is an output section, and 10 is a signal output terminal.

Claims (1)

[Scope of Claims] 1. A plurality of light-receiving element portions arranged in a plurality of horizontal rows and a plurality of vertical rows and accumulating signal charges by receiving light, each of the plurality of vertical rows formed by the light-receiving element portions. a vertical transfer section for transferring signal charges; a first gate for reading out signal charges accumulated in the odd-numbered light-receiving element sections forming each of the plurality of vertical columns to the vertical transfer section; and a light receiving/vertical transfer section including a second gate section for reading signal charges accumulated in even-numbered light receiving element sections forming each of the plurality of vertical columns to the vertical transfer section; , a charge absorption section adjacent to one end of each of the vertical transfer sections; a first storage section adjacent to the other end of each of the vertical transfer sections; and a second storage section adjacent to the first storage section. a storage unit; a horizontal transfer unit adjacent to the second storage unit and extending along each of the plurality of horizontal columns; and adjacent to the horizontal transfer unit, converting the transferred signal charge into an imaging output signal. an output section provided in the light receiving/vertical transfer section and the first and second storage sections, and in a standby period, an output section is provided in the light receiving/vertical transfer section and the first and second storage sections; An operation is performed to cause the charge to flow out to the vertical transfer section, and during the subsequent light reception period, the vertical transfer section is caused to perform an operation to transfer the charge there to the charge absorption section, and subsequent first readout and vertical transfer are performed. During the period, the vertical transfer section and the first storage section perform an operation of transferring and storing signal charges read into the vertical transfer section through the first gate section to the first storage section. Then, during a second readout and vertical transfer period, the signal charges read out to the vertical transfer section through the second gate are transferred to the vertical transfer section and the first and second storage sections. At the same time, the signal charge stored in the first storage section is transferred to and stored in the second storage section, and further, each horizontal block For each period corresponding to the ranking period, the signal charges stored in the first and second storage sections are received to form respective odd-numbered or even-numbered ones of the plurality of horizontal columns. a first terminal group to which a drive signal is supplied to sequentially transfer signal charges corresponding to the signal charges accumulated in the element section to the horizontal transfer section; and a first terminal group provided in the horizontal transfer section for each horizontal video period. a second terminal group to which a drive signal is supplied that causes the horizontal transfer section to perform an operation of transferring the signal charge from the second storage section to the output section during a period corresponding to . solid-state imaging device.