JP3154146B2 - Solid-state imaging device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid-state imaging device, and more particularly to a solid-state imaging device suitable for use in an imaging device such as a video camera.

[0002]

2. Description of the Related Art The aspect ratio of a display screen of a television receiver (hereinafter referred to as a TV monitor) is 4 in the case of a television system such as NTSC or PAL. : 3, and in the case of a television system such as wide ED or HD, the standard is 16: 9. However, a conventional solid-state imaging device has a configuration as shown in FIG. 4, for example. However, this figure is a diagram showing an example of a conventional interline transfer (IT) CCD image sensor.

As is apparent from FIG. 4, the image pickup section 4 has a large number of pixel-based photosensors 1 arranged in a two-dimensional array. The pixel signals are read out to the CCD 3 and these pixel signals are transferred in the vertical direction. The pixel signal output from the image pickup unit 4 is transferred in parallel to the horizontal transfer CCD 5 line by line and read out therefrom in series. It has become.

According to this configuration, the imaging unit 4 and the horizontal transfer C
Since the CDs 5 are fixedly associated with each other, different horizontal transfer CCDs are provided if the horizontal length of the imaging unit 4 is different.

Therefore, using a conventional solid-state imaging device,
In the case of capturing images of television systems having different aspect ratios, it is necessary to prepare separate video cameras.

As an improvement on this point, the image pickup unit 4 shown in FIG. 4 is made to be a horizontally long one corresponding to a wide aspect ratio (16: 9), and an image signal picked up by the image pickup unit is transferred horizontally.
5, the image signal is read out by an external circuit (not shown) by A / A.
There has been proposed a method of obtaining a normal aspect image signal by extracting a portion of the image signal corresponding to a normal aspect (4: 3) from the image signal by performing D conversion and performing digital processing.

[0007]

However, this method is
It has the drawback that complicated digital signal processing must be performed. SUMMARY OF THE INVENTION The present invention has been made to overcome the above-described drawbacks, and does not require complicated digital signal processing. It is an object of the present invention to provide a solid-state imaging device capable of reading both signals.

[0008]

As shown in FIG. 1, for example, a solid-state imaging device according to the present invention has a first light receiving portion (part A) having a first aspect ratio and additional light receiving portions on both sides of the first light receiving portion. And a second aspect ratio (A + B) together with the first light receiving section.
+ C part) (second light receiving part (B + C part))
An imaging unit 4 having a vertical transfer unit for vertically transferring signal charges read from the first light receiving unit and the second light receiving unit; and a vertical unit from the first and second light receiving units of the imaging unit 4. Transfer signal charges are input in parallel for each horizontal line, and the first
It is output in series at the read clock frequency and the first
A first horizontal transfer unit 5 having an output unit; a signal charge corresponding to the first light receiving unit is transferred and input from the signal charge of the first horizontal transfer unit; the signal charge is output in series at a second read clock frequency; Second horizontal transfer unit 7 having a second output unit
A transfer gate 10 formed between the first and second horizontal transfer units (5, 7) for controlling transfer of signal charges between the first and second horizontal transfer units; and the first horizontal transfer unit 5, an unnecessary charge discharging unit 12 for discharging unnecessary charges, and in the read mode having the second aspect ratio, the first and second unnecessary charges are removed.
The signal charge of the light receiving section is transferred from the first horizontal transfer section 5 to the first
In the readout mode of the first aspect ratio, the signal charges of the first light receiving unit are read out from the second horizontal transfer unit 7 to the second output unit, and the signal charges of the second light receiving unit are read out. The signal charge of the first light receiving section provided to the second horizontal transfer section 7 is discharged from the first horizontal transfer section 5 to the first output section by a clock for reading from the second horizontal transfer section 7 to the second output section. To do.

In the solid-state imaging device according to the present invention, the first read clock frequency is set higher than the second read clock frequency.

Further, in the solid-state imaging device of the present invention, the first horizontal transfer section is used as a drain in the read mode of the first aspect ratio.

[0011]

According to the above arrangement of the present invention, two first and second horizontal transfer units are provided for one image pickup unit, and image signals having different aspect ratios are read out. In addition, it is not necessary to prepare a separate imaging device to obtain image signals having different aspect ratios. Since image signals having different aspect ratios are read out through separate horizontal transfer units, there is no need to perform complicated digital signal processing on output signals. By setting the readout frequency of the first horizontal transfer unit higher than the readout frequency of the second horizontal transfer unit, signals with a large amount of information can be satisfactorily dealt with.
When the normal aspect image signal is being read from the second horizontal transfer unit, unnecessary electric charges are discharged using the first horizontal transfer unit as a drain, so that the apparatus is simplified.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the solid-state imaging device according to the present invention will be described with reference to FIG. In the figure, reference numeral 4 denotes an imaging unit, for example, a wide aspect (a: c = 1) of effective 480,000 pixels
6: 9). For the sake of explanation, this imaging unit is divided into a region A (hereinafter referred to as a “first light receiving unit”) corresponding to a conventional normal aspect (b: c = 4: 3), and regions B and C added on both sides thereof. (Hereinafter referred to as “second light receiving unit”), but there is no boundary between the regions. The imaging unit shown in the figure indicates an image unit when it is constituted by an interline transfer (IT) CCD as shown in FIG.
In the case of frame transfer (FIT), it indicates a storage unit. 5 is a first horizontal transfer CCD, 6 and 8 are output amplifiers, 7 is a second horizontal transfer CCD, 10 is a transfer gate, and 9 and 11 are barriers.

The first horizontal transfer CCD is formed in the same manner as the horizontal transfer CCD of the conventional solid-state image pickup device.
.About.V.phi.4 to receive all signals transferred in the vertical direction. The transfer gate 10 controls the signal charges transferred from the image pickup unit 4 to the first horizontal transfer CCD by A
The signal charge of the portion corresponding to the portion (first light receiving portion) is
It is for transferring to the horizontal transfer CCD, and the length is b. Portions 9 and 11 indicated by hatching at both ends of the transfer gate indicate that the signal charges in the first horizontal transfer CCD are the second.
This is a barrier for preventing transfer to the horizontal transfer CCD, and the total length of the transfer gate 10 and the barriers 9 and 11 is a. The second horizontal transfer CCD is the first
It is composed of the same as the horizontal transfer CCD. These first
The second horizontal transfer CCD sequentially shifts pixel signal charges to the left by clock signals supplied to Hφ1 and Hφ2, and outputs the same through output amplifiers 6 and 8. HHG2 is an input terminal of a signal supplied to the CCD electrode of the transfer gate 10 for controlling transfer or inhibition in cooperation with the potentials of Hφ1 and Hφ2.

Next, the operation of the solid-state imaging device having such a configuration will be described.

First, a case where a wide aspect image signal is read from the solid-state imaging device will be described. The transfer of the pixel signal charges from the imaging unit 4 is performed by clocks Vφ1 to Vφ4 according to a known method.

Next, during the horizontal blanking period HBLK shown in FIG. 2A, the charge of the image pickup unit is simultaneously transferred to the first horizontal transfer CCD 5 in parallel with the clock Vφ4 shown in FIG. 2B. At this time, as shown in FIGS. 2C and 2D, the clock terminal potential of the first horizontal transfer CCD 5 is such that Hφ1 is at a high level and Hφ2 is at a low level. Since the HHG2 signal applied to the transfer gate 10 is at a low level as shown in FIG. 2 (F), no charge is transferred here. That is, the transfer gate is closed.

Next, the pixel signals in the first horizontal transfer CCD 5 are read out serially at a frequency of 18 MHz by the clocks Hφ1 and Hφ2 in a usual manner.

Next, an operation for extracting a normal aspect (4: 3) image signal from the solid-state imaging device will be described. First horizontal transfer CCD for image signal of image pickup unit
5 is the same as that in the case of reading a wide aspect image signal.
The pixel signal charges of the light receiving section are transferred to the first horizontal transfer CCD 5. However, when an image signal of a normal aspect is obtained, since a high-level potential is applied to HHG2 as shown in FIG. 3F, the Hφ1 potential is reduced as shown in FIG. When the signal level goes low, the pixel signal charges are transferred to below the HHG2 electrode, and subsequently the pixel signal charge is transferred to Hφ1.
When the potential becomes high level, these charges are transferred to the second horizontal transfer CCD 7. That is, the transfer gate is opened and the first signal corresponding to the normal aspect image signal is output.
The pixel signal charges from the light receiving section are transferred to the second horizontal transfer CCD 7.

When a normal aspect image signal is taken out, it is not necessary to output a pixel signal from the second light receiving section.
There is no transfer from the horizontal transfer CCD 5 to the second horizontal transfer CCD 7.

Next, as described above, the second horizontal transfer CC
The normal aspect pixel signal transferred to D7 is Hφ
1 and read out in series in a usual manner by a clock having a frequency of 13.5 MHz given to Hφ2. At this time,
The signal charge corresponding to the second light receiving portion remaining in the first horizontal transfer CCD is also read out by the clock supplied to Hφ1 and Hφ2 and is discarded. That is, the first horizontal transfer CCD 5 functions as a drain for discharging unnecessary charges.

In the above description, the wide aspect (1
6: 9), the first horizontal transfer CC
Although the description has been made on the assumption that only D5 is used for reading the image signal, the transfer control is performed so that both the first and second horizontal transfer CCDs 5 and 7 are used when reading the wide aspect image signal. This can reduce the clock frequency for transfer, which is advantageous in circuit design. It is apparent from the above description that the method of the present invention is applicable not only to a solid-state imaging device having 480,000 pixels but also to a solid-state imaging device having another number of pixels.

[0022]

According to the present invention, both a wide aspect image signal and a normal aspect image signal can be read out using one solid-state imaging device. By improving the horizontal transfer section as compared with the conventional solid-state imaging device, both signals can be separately extracted with a simple configuration. Moreover, no external circuit for performing complicated digital signal processing is required.

[0023]

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating an embodiment of a solid-state imaging device according to the present invention.

FIG. 2 is a block diagram showing a conventional interline transfer CCD imaging device.

FIG. 3 is a signal waveform diagram at the time of reading a wide aspect image.

FIG. 4 is a signal waveform diagram when a normal aspect image is read.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Photosensor 2 Read gate 3 Vertical transfer CCD 4 Imaging part 5 First horizontal transfer CCD 7 Second horizontal transfer CCD 10 Transfer gate 9, 11 Barrier

Claims (2)

(57) [Claims] A first aspect ratio of the first light receiving section;
A second light-receiving unit, which is added to each side of the light-receiving unit and forms a second aspect ratio together with the first light-receiving unit, and vertically transfers signal charges read from the first light-receiving unit and the second light-receiving unit; An image pickup unit having a vertical transfer unit, and vertical transfer signal charges from the first and second light receiving units of the image pickup unit are transferred in parallel for each horizontal line, output in series at a first read clock frequency, and A first horizontal transfer unit having a first output unit, and a signal charge corresponding to the first light receiving unit is transferred and input from the signal charge of the first horizontal transfer unit, and is output in series at a second read clock frequency. A second horizontal transfer section having a second output section at one end, and a transfer gate for controlling transfer of signal charges between the first and second horizontal transfer sections formed between the first and second horizontal transfer sections. No need for the first horizontal transfer unit An unnecessary charge discharging unit that discharges charges;
And reading the signal charges of the second light receiving unit from the first horizontal transfer unit to the first output unit, and in the read mode of the first aspect ratio,
The signal charge of the light receiving section is read out from the second horizontal transfer section to the second output section, and the signal charge of the first light receiving section, which receives the signal charge of the second light receiving section to the second horizontal transfer section, A solid-state imaging device wherein the first horizontal transfer unit outputs the first output unit in response to a clock read from the second horizontal transfer unit to the second output unit. 2. The solid-state imaging device according to claim 1, wherein said first read clock frequency is higher than said second read clock frequency.