JP2005175986A - Image input device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image input device constituting a light control system without a time lag capable of coping even with viewing angle change by an exchange lens. <P>SOLUTION: A pixel constituting a solid-state imaging device is provided with a light receiving part for receiving light and converting it to a stored charge, an FD part for converting the stored charge stored in the light receiving part to a voltage, a transfer channel for performing the transfer of the FD part from the light receiving part, and a reset channel for resetting the FD to a reset voltage. By abolishing a part or all of the light shielding film of the FD part, the FD part also receives the light and generates a light charge. In a period in which a stroboscope is made to emit the light and the light charge is stored in the light receiving part, by closing the transfer channel and opening the reset channel, the FD part is reset, a current flowing to the reset channel is monitored, the emitted light quantity of the stroboscope is detected, and a shutter is closed according to the detected quantity. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to strobe photography of an image input apparatus, and more particularly to TTL light control using an individual image sensor.

  Conventionally, in an image input device such as a digital camera, in the case of flash photography, an external light control method in which reflected light from a flash subject is received by an external light control element, and exposure is controlled according to the output, or Prior to the main light emission, preliminary light emission is performed, and the exposure control during the main light emission is controlled according to the reflected light of the preliminary light emission.

  The configuration of this conventional image input apparatus is shown in FIG. The subject is focused on the individual image sensor 4 via the lens 1. This light can be blocked from entering the solid-state imaging device by the shutter 3. Further, when the mirror 2 is at the position shown in the figure, incident light from the lens is reflected by the mirror and guided to the AE sensor 5.

  The mirror is controlled by the mirror driving device 6 and moves to a position where incident light reaches the solid-state imaging device. The shutter is controlled by a shutter driving device 7. The individual image sensor is driven by the individual image sensor drive circuit 8 and takes out optical information on the individual image sensor as electrical information.

  During flash photography, the flash 9 emits light. The reflection of the strobe light from the subject is received by the external light control sensor 100, and the shutter is closed according to the output, thereby adjusting the individual image sensor so that the appropriate light reaches the individual image sensor. Control of these sequences is performed by the CPU 11.

Further, in the same configuration, by performing preliminary light emission before the main light emission of the strobe, the reflected light of the preliminary fermentation is received by the AE sensor, and the light emission amount and shutter speed of the main light emission are controlled according to the output. It is known that the same effect can be obtained.
JP 2001-326850 A

  However, in the configuration of the above-described conventional example, it is difficult to adopt a TTL configuration for the external light control sensor, and thus there is a problem that it is difficult to cope with a change in the angle of view using an interchangeable lens or the like.

  Further, Patent Document 1 has a problem that a time lag between preliminary light emission and main light emission occurs.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an image input device that constitutes a light control system that can cope with a change in the angle of view by an interchangeable lens and has no time lag.

  In order to solve the above-described problems, the present invention uses a CMOS sensor as an individual imaging device, and pixels constituting the CMOS sensor include a light receiving unit that receives light and converts it into accumulated charges, and a storage electrification accumulated in the light receiving unit. A FD unit that converts the voltage into a voltage; a transfer channel for transferring the FD unit from the light receiving unit; and a reset channel that resets the FD to a reset voltage; and part or all of the light shielding film of the FD unit. By abolishing the structure, the FD unit also receives light and generates a photocharge.

  The image input device using the CMOS sensor with this configuration causes the strobe to emit light and resets the FD unit by closing the transfer channel and opening the reset channel while the photocharge is accumulated in the light receiving unit. By monitoring the current flowing through the reset channel, detecting the amount of light emitted from the strobe, and closing the shutter according to the detected amount, it is possible to obtain an appropriate exposure amount by performing dimming control.

  According to the present invention, while the strobe is caused to emit light and the photoelectric charge is accumulated in the light receiving portion, the transfer channel is closed and the reset channel is opened, thereby resetting the FD portion and monitoring the current flowing through the reset channel. Then, by detecting the light emission amount of the strobe and closing the shutter according to the detected amount, it is possible to obtain an appropriate exposure amount by performing dimming control.

  In addition, it is possible to configure a light control system that can cope with a change in the angle of view by an interchangeable lens and has no time lag.

BEST MODE FOR CARRYING OUT THE INVENTION

  Examples of the present invention will be described below.

  An image input apparatus according to a first embodiment of the present invention will be described below with reference to FIGS.

  FIG. 1 shows the configuration of an image input apparatus embodying the present invention. The subject is focused on the CMOS sensor, which is the individual image sensor 4, through the lens 1. This light can be blocked from entering the solid-state image sensor 4 by the shutter 3. Further, when the mirror 2 is at the position shown in the figure, incident light from the lens is reflected by the mirror and guided to the AE sensor 5.

  The mirror is controlled by the mirror driving device 6 and moves to a position where incident light reaches the solid-state imaging device 4. The shutter 3 is controlled by a shutter driving device 7. The individual image sensor is driven by the individual image sensor drive circuit 8 and takes out optical information on the individual image sensor as electrical information.

  During flash photography, the flash 9 emits light. The amount of light emission is monitored by the reset current of the individual image sensor 4. The output is detected by the reset current monitor device 10, and the shutter 3 is closed at the timing when an appropriate exposure amount is reached accordingly. Control of these sequences is performed by the CPU 11.

  Here, the structure of a CMOS sensor as the individual imaging element 4 is shown in FIG.

  This has a configuration in which a predetermined number of pixels 12 are arranged vertically and horizontally. Further, FIG. 3 shows a pixel structure.

  A photodiode 21 that receives incident light, an FD 22 that performs charge-voltage conversion, a transfer channel 23 that transfers light and charges from the photodiode to the FD 22, a reset channel 24 that resets the FD 22 to a reset voltage, and a current that flows through the reset channel. It comprises a detector (in this case, a resistor) 25 for monitoring.

  During the period in which the sensor accumulates incident light from the subject, the transfer channel 23 is closed and the reset channel 24 is opened. As a result, photoelectric charges corresponding to incident light are accumulated in the photodiode, and the FD 22 is connected to the reset voltage.

  At this time, the light incident on the FD 22 part is also photoelectrically converted in the FD 22 part and flows into the reset channel 24 as a photocurrent. This can be monitored by a reset current detector, which monitors the light incident on the sensor during strobe photography.

  Further, FIG. 4 shows a configuration diagram of the reset current monitoring device.

  The output from the pixel reset current detector is inverted by the inverting amplifier 31, and the output is integrated by the integrator 32.

  The output from the reset current detector is a photocurrent, which is the light output at that moment. By integrating this, it is converted into a total light output during the accumulation period and transmitted to the CPU 11 which is the control unit.

  According to this result, it can be detected that an appropriate amount of light has accumulated in the sensor, and the shutter 3 can be closed at that timing.

  With the above configuration, it is possible to perform proper dimming by monitoring the light quantity of the main light emission of the strobe without using an external light control element and without using preliminary light emission.

  Although not described in this embodiment, it is obvious that the output from the reset current detector as a result of adding the reset currents of a plurality of pixels is also prepared due to the structure of the CMOS sensor.

It is a figure which shows the structure of the image input device of the Example of this invention. It is a figure which shows the structure of the solid-state image sensor of the Example of this invention. It is a figure which shows the structure of the pixel of the solid-state image sensor of the Example of this invention. It is a block diagram of the reset current monitor apparatus of the Example of this invention. It is a figure which shows the structure of the conventional image input device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Lens 2 Mirror 3 Shutter 4 Solid-state image sensor 5 AE sensor 6 Mirror drive device 7 Shutter drive device 8 Solid-state image sensor drive circuit 9 Strobe 10 Reset current monitor device 11 CPU

Claims (2)

In an image input device comprising a solid-state imaging device comprising a plurality of pixels and converting an optical image into an electrical signal, a shutter for blocking light reaching the individual imaging device, and a strobe.
The pixels constituting the solid-state imaging device receive a light and convert it into accumulated charges, an FD unit that converts the accumulated electrical charge accumulated in the light receiving unit into a voltage, and transfers the FD unit from the light receiving unit. A transfer channel for performing, and a reset channel for resetting the FD to a reset voltage,
By eliminating part or all of the light-shielding film of the FD unit, the FD unit is also configured to receive light and generate photocharges, to emit strobe light, and to accumulate photocharges in the light receiving unit. During this period, the transfer channel is closed and the reset channel is opened, thereby resetting the FD unit, monitoring the current flowing through the reset channel, detecting the amount of light emitted from the strobe, and closing the shutter according to the detected amount. A characteristic image input device.   The image input device according to claim 1, wherein the solid-state image sensor is a CMOS sensor.

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