JPH04167776A - Driving device for image pickup device and solid-state image pickup element - Google Patents

Abstract

PURPOSE:To perform exposure control suitable for the conditions of an object with constant active resolution by selecting or combining specific two driving modes based on the conditions of the object. CONSTITUTION:In a frame interline transfer type CCD sensor, the electric charge from a sensor part 1 is shifted to a vertical transfer register 2, transferred to a storage part 3 during vertical retrace line, then, shifted to a horizontal transfer register 4 at the prescribed timing, and read out through an output amplifier 5. In such a case, the information is discretely stored and a first driving mode performing the storage of information all over the entire one field period and a second driving mode continuously performing one storage are selected or combined to use based on the conditions of the object. Thus, the exposure control suitable for the conditions of the object with constant active resolution can be performed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an imaging device such as a solid-state imaging device used in, for example, a video camera, and a driving device for the solid-state imaging device.

[Prior Art] Conventionally, as a means of realizing a function called exposure compensation in video cameras, etc., there have been methods that use aperture blades, etc., to directly control the amount of light incident on the image sensor, and methods that control the charge accumulation time of the image sensor. There are some that use a so-called electronic shutter function.

[Problems to be Solved by the Invention] However, among the conventional methods described above, the method using aperture blades requires the aperture blades and mechanical members around them, so it is difficult to increase the size and height of video cameras, etc. There was a problem in that it led to increased costs. Furthermore, the method using the electronic shutter function has the problem that the movement of the captured image becomes unnatural.

Among the above-mentioned problems, problems with the method using the electronic shutter function will be described in more detail below.

FIG. 3 is a conceptual diagram of an incline transfer type CCD, in which ``■'' is a sensor section that performs photoelectric conversion, 2 is a vertical transfer register, 4 is a horizontal transfer register, and 5 is an output amplifier. The cross-sectional view and potential diagram along the line A-A' in the figure are the fourth.
It is a diagram.

In Figure 4, 6 is a channel stop for pixel separation (C3
), 7 is a readout gate (ROG) for transferring the charges accumulated in the sensor section 1 to the vertical transfer register 2, 8 is a substrate plate, and 9 is an oxide film.

The operation of the electronic shutter will be explained with reference to FIGS. 4 and 5. FIG. 5 is a diagram of the ] field of a standard television signal, where φROG is a pulse applied to the readout gate 7, and when the logic level is "H",
The potential of the readout gate 7 decreases, and the charge in the sensor section 1 is transferred to the vertical transfer register 2. Removal pulse φ
SUB is a pulse applied to the substrate 8, and when it is “H”, the charge accumulated in the sensor unit 1, φS
It is swept out (removed) through the OB terminal.

In this conventional example, in FIG. 5, φROG is in the vertical retrace period, and φSUB is in the horizontal retrace period. After reading the electric charge of the sensor unit 1 at time to, the next period starts, but during the horizontal retrace period at time t1, φ5UB=”
H”, the charge from to to tl is the sensor part 1.
There are no leftovers. φ5U from time t1 to t2
Since B="L", the charge during this period is accumulated in the sensor section 1, and is transferred to the vertical transfer register 2 by the φROG="H" pulse at time t2. After all, the exposure time in this case is (
t2-tl).

Therefore, although it functions well as an electronic shutter, when using the conventional electronic shutter function for exposure compensation, especially when trying to continuously vary the exposure time,
There was a problem in that the difference in dynamic resolution between each exposure time appeared on the screen as it was, resulting in an extremely unsightly screen where the dynamic resolution changed for each field.

Therefore, the present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide an imaging device and a solid-state imaging device with constant dynamic resolution and furthermore, capable of controlling exposure appropriate to the conditions of the subject. The purpose of this invention is to provide a driving device for the following.

[Means for Solving the Problems] In order to solve the above-mentioned problems and achieve the purpose, the imaging device of the present invention has a first method that obtains a predetermined total storage time by discretely performing storage a plurality of times. The control means has a drive mode and a second drive mode in which the predetermined period of accumulation time is obtained by performing one continuous accumulation.

Further, the driving device for a solid-state image sensor of the present invention includes a sensing means for receiving an optical signal, performing photoelectric conversion and storing information, a first storage means for reading information from the sensing means, and a first storage means for reading information from the sensing means. a second storage means for storing information from the storage means; and a removal means for removing information from the sensing means, wherein the information from the sensing means is intermittently removed on the same side within an l field period. A driving device for a solid-state image sensor that controls information storage time by removing the information by a means, the sensing device controlling the sensing time after a predetermined time from the end of the operation for each operation of the removing means a plurality of times within one field period. a first driving mode in which the information of the removing means is read into the first storage means; and within one field period, after completing all the operations of the removing means within one field period, the sensing means The second driving mode has a second driving mode for reading information from the first storage means into the first storage means, and the first driving mode and the second driving mode can be selected or combined.

[Operation] In the above configuration, the present invention has a first drive mode in which information is accumulated in an 8II manner and is accumulated evenly over the entire one field period, and a first drive mode in which information is accumulated one time continuously. By selecting the second drive mode depending on the conditions of the subject or using them in combination, it is possible to maintain a constant dynamic resolution and perform exposure control suitable for the conditions of the subject.

[Embodiment] Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 2 is a conceptual diagram of the CCD sensor used in this example. This sensor is called a frame interline transfer type CCD, and the difference from FIG. 3 is that it includes a storage section 3 (second storage means). The number of memory cells in the memory section 3 is the same as the number of cells in the sensor section 1 (sensing means). The charge from the sensor section 1 is transferred to the vertical transfer register 2 (first storage means), then transferred to the storage section 3 during the vertical retrace period, and then transferred to the horizontal transfer register 4 at a predetermined timing. , are read out through the output amplifier 5 and row (.

Furthermore, the cross-sectional view and potential diagram along the line A-A'' in FIG. 2 are the same as those in FIG. The same is true.

FIG. 1(a) is a diagram explaining the operation of this embodiment.
The driving method when the CCD sensor shown in the figure stores information discretely within one field period and performs exposure compensation (
(hereinafter referred to as "multi-exposure").

At time tlO, the charge of the previous sensor unit 1 is
is sent to vertical transfer register 2, and vertical transfer register 2
Charges for one field are sent to the storage unit 3 at high speed during the vertical retrace period (vertical transfer period in the figure). After that, as shown, at each time t11°t12. ---, tn±9
, the period al immediately before tn+lo.

In order to make a2, an-1, and an the charge accumulation period,
The removal pulse φSOB is driven as shown in the figure.

As a result, the charge is swept out (removed) and accumulated in a discrete manner. t11. t12.・・・・・・、tn
+9, read pulse φROG at tn+10
As a result, charges are transferred from the sensor section 1 to the vertical transfer register 2.

Therefore, at time tn+10, the transfer pulse φROG becomes °.

The vertical transfer register 2 immediately after the end of the "H" period stores the sum of the charges generated in the sensor section 1 during the accumulation periods al, a, 2, . . . an. That is, the removal pulse φS within one field period
The total sum of charges accumulated in the vertical transfer register 2 is controlled by each application period and number of times of UB, and the CCD sensor itself functions as a shutter.

Here, the generation timing of the φSUB removal pulse and the φ
The generation timing of the ROG transfer pulse is set within or near the horizontal retrace period of the standard television signal. This is the φSUB removal pulse or φROG
This is because if the transfer pulse is generated at a timing other than the above, it will appear as noise on the screen.

Next, the operation of realizing the conventional electronic shutter operation described above using the CCD element used in this embodiment will be explained with reference to FIG. 1(b).

As shown in the figure, a φROG transfer pulse is applied once within one field period (TIO, Tll, . . . ), and a φSUB removal pulse (T2O) is applied once within that period.

) is applied.

As a result, the charge is swept out (removed) and accumulated once each within one field period.

Therefore, immediately after the period in which the transfer pulse φROG is "H" ends at time Tll, the vertical transfer register 2 stores the sum of the charges generated in the sensor section 1 during the storage period A1.

Next, the above-mentioned multi-exposure mode (first drive mode)
and conventional electronic shutter mode (second drive mode)
We will explain how to use them properly.

First, in the multi-exposure mode, as shown in Figure 1(a), the accumulation time is distributed evenly and discretely within one field period, so it is difficult to capture images of subjects with large temporal changes in brightness. , there is no change in dynamic resolution (very effective. However, conversely, the subject image received during the accumulation period al and the subject image received during the accumulation period an are 1/
Since there is a time difference of nearly 60 seconds, the dynamic resolution decreases for fast-moving subjects. In addition, although the conventional electronic shutter mode has the drawbacks mentioned above,
In particular, for subjects with small temporal changes in brightness and fast movement, changes in dynamic resolution are not so noticeable, and images with good dynamic resolution can be photographed.

Therefore, for example, if the subject is moving slowly or if the subject's brightness changes greatly, select the multi-exposure mode, and if the subject is moving quickly, select the multi-exposure mode. By selecting the conventional electronic shutter mode, there is little change in dynamic resolution (and images with good dynamic resolution can be captured).

As explained above, according to the present invention, there is an exposure control mode in which the accumulation time is evenly distributed for a predetermined number of times and for a predetermined time within one field period, and an exposure control mode in which the accumulation time is evenly distributed for a predetermined time within one field period; A mode for controlling exposure time can be realized by simply changing the drive control using the same solid-state image sensor. Therefore, by using these two modes separately or in combination, exposure control suitable for the conditions of the subject and the intention of photographing becomes possible.

Furthermore, in this embodiment, when performing the conventional electronic shutter operation, one transfer pulse φRO is generated within one field period.
G, an example in which the removal pulse φSOB is applied once has been described, but as shown in the middle of one field period as shown in FIG. 1(c), the φROG transfer pulse t11. ..., tl
φSUB removal pulse T that ends before generating o+n
21. ..., t20+m may be configured. The same effect as in the case of FIG. 1(b) can be obtained since the accumulation period is Al.

Note that the present invention can be applied to modifications or variations of the above embodiments without departing from the spirit thereof.

For example, in this embodiment, the case where one field period is 1/60 second has been described, but the time period is not limited to this. Moreover, it may be applied not only to two-dimensional sensors but also to -dimensional sensors.

[Effects of the Invention] As described above, according to the present invention, the first drive mode stores information discretely and stores the information evenly throughout one field period; By selecting the second drive mode, which performs one continuous accumulation, depending on the conditions of the subject, or using it in combination, it is possible to maintain a constant dynamic resolution and perform exposure control that is suitable for the conditions of the subject. There is an effect.

[Brief explanation of the drawing]

Figures 1 (a), (b), and (c) are diagrams explaining the operation of an embodiment of the present invention, Figure 2 is a conceptual diagram of a frame interline transfer type CCD used in the embodiment, and Figure 3 is a diagram illustrating the operation of an embodiment of the present invention. FIG. 4 is a conceptual diagram of an interline transfer type CCD. FIG. 4 is a sectional view and potential diagram taken along line AA' in FIG. 3. FIG. 5 is a diagram explaining the operation of a conventional electronic shutter. In the figure, 1... sensor section (sensing section), 2... vertical transfer register (first storage means), 3... storage section (
(second storage means). \noku nu

Claims (3)

[Claims] (1) A first drive mode that obtains a predetermined total accumulation time by performing accumulation discretely multiple times, and a second drive mode that obtains the predetermined total accumulation time by performing one continuous accumulation. An imaging device including a control means having a drive mode. (2) sensing means that receives optical signals and performs photoelectric conversion and stores information; first storage means that reads information from the sensing means; and second storage means that stores information from the first storage means. and a removing means for removing the information of the sensing means, the information storage means for storing information of the sensing means, and a removing means for removing the information of the sensing means.
A driving device for a solid-state image sensing device that controls information storage time by causing the removing means to remove information from the sensing means intermittently more than once, the removing device removing the information a plurality of times within one field period. a first driving mode in which, for each operation, the information of the sensing means is read into the first storage means after a predetermined time from the end of the operation; and one field of the removing means within one field period. It has a second drive mode in which the information from the sensing means is read into the first storage means after completing all the operations within the period, and the first drive mode and the second drive 1. A driving device for a solid-state image sensor, characterized in that modes are selectable or combinable. (3) The timing of moving information from the sensing means to the first storage means and the timing of removing information from the sensing means are within or near the horizontal retrace period of a standard television signal. A driving device for a solid-state image sensor according to claim 2.