JP2007215065A - Imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an imaging apparatus which easily corrects a variation of an exposure time occurred by an individual difference of operation characteristics of a mechanical shutter, is inexpensive, has a high productivity, and is provided with a high image quality. <P>SOLUTION: The operation characteristics each individual of the mechanical shutter 2 are stored in a storage portion 13. The variation of the exposure time caused by an operational fluctuation of the mechanical shutter 2 is adjusted by varying an amplification factor of a signal from an imaging element 5 based on the operation characteristics of the mechanical shutter 2 stored in the storage portion 13. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an imaging device provided with a mechanical shutter.

  A conventional imaging device is configured to form a subject image formed on the basis of a light beam incident on a photographing optical system composed of a plurality of lens groups on an imaging element such as a CCD or CMOS arranged at a predetermined position. There is something that was done.

  In such an image pickup apparatus, an electronic shutter that electrically controls charge accumulation in the image sensor is used to control the charge accumulation time of the image sensor. The image sensor is always exposed to light, and only when the shutter button is pressed, the electronic shutter is opened at high speed, and after photoelectric conversion by the image sensor, it is transferred to the memory as image information. Since the electronic shutter uses the movement of the image sensor alone, there is a merit that the shutter speed is fast. However, if the image sensor is exposed to strong light during charge transfer, the light is further added to the original charge. , The charge may leak out. As a result, the electric charge leaked in the vertical direction, that is, vertical light streaks (smear) appears in the photograph. For this reason, in addition to an electronic shutter, there is known a method for preventing this smear by using a mechanical shutter that physically shields a light beam incident on an image sensor.

  Next, the operating characteristics of the mechanical shutter will be described.

  As shown in FIG. 4, the closing operation of the mechanical shutter is started by energization (T1) to the electromagnetic motor of the mechanical shutter. At this time, a mechanical delay occurs until the mechanical shutter blades block the aperture of the light beam of incident light (this is referred to as “mechanical delay” (T2-T1)), and further, the mechanical shutter blades. However, it takes time from the start of shielding the aperture until it is completely shielded (this is referred to as “closing time” (T4-T2)).

  The time (T3-T0) from the start of charge accumulation in the image sensor by the electronic shutter (T0) until the half of the aperture (50% AV) is shielded by the mechanical shutter (T3-T0) is the effective exposure time. . That is, the effective exposure time is represented by AE time (T1-T0) + mechanical delay (T2-T1) + close time / 2 (T3-T2).

  In general, the mechanical shutter has a structure in which a plurality of blades are opened and closed by an electromagnetic motor, and the individual characteristics of the operating characteristics (mechanical delay and closing time) of the mechanical shutter increase. For this reason, the effective exposure time also varies and the exposure error increases.

Therefore, in the conventional imaging device, the closing operation characteristics of the mechanical shutter mounted on the detachable lens barrel are recorded in the storage unit, and the timing of the electronic shutter is adjusted by the closing operation characteristics of the mechanical shutter, Variations in the characteristics of the mechanical shutter for each lens barrel to be attached were reduced to reduce the exposure error (see JP-A-1-179574: Patent Document 1).
JP-A-1-179574

  However, in the conventional imaging device, the characteristic variation of the mechanical shutter is adjusted by the timing of the electronic shutter, but the adjustment of the operation timing on the time axis is complicated and the operation control becomes complicated. In addition, it is difficult to simultaneously adjust the sensitivity variation of the image sensor. Furthermore, it is difficult to manage the individual characteristics of the mechanical shutter on the recording unit in a one-to-one correspondence with the imaging device, but this method is not disclosed.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an imaging device that can correct the operating characteristics of a mechanical shutter by a simple method, is excellent in productivity, is inexpensive, and has high image quality.

In order to solve the above problems, an imaging apparatus of the present invention provides:
An image sensor for converting a subject image into an electrical signal;
A mechanical shutter that blocks incident light to the imaging element and limits imaging time;
An amplifier for amplifying the electrical signal converted by the imaging device;
A recording unit for recording operating characteristics of the mechanical shutter;
And an adjusting unit that adjusts the amplification factor of the amplifying unit based on the operating characteristics of the mechanical shutter recorded in the recording unit.

  According to the imaging apparatus of the present invention, since the adjustment unit that adjusts the amplification factor of the amplification unit based on the operation characteristic of the mechanical shutter recorded in the recording unit is provided, the operation of each mechanical shutter is operated individually. By recording the characteristics in the recording unit and adjusting the amplification factor of the electrical signal of the imaging device by the adjustment unit, it is possible to easily correct the variation in the exposure amount due to the variation in the operating characteristics of each mechanical shutter. Thus, an image sensor with high image quality can be obtained.

  In one embodiment, the operating characteristic of the mechanical shutter is at least one of a mechanical delay time of the mechanical shutter or a closing time of the mechanical shutter.

  Here, the “mechanical delay time of the mechanical shutter” refers to the time from the start of energization to the mechanical shutter until the mechanical shutter starts to block the aperture of the light beam incident on the image sensor. . The “closing time of the mechanical shutter” means that the aperture of the light beam incident on the image sensor after the mechanical shutter starts to shield the aperture of the light beam incident on the image sensor is completely reduced. Time to shield.

  According to the imaging apparatus of this embodiment, the operating characteristic of the mechanical shutter is at least one of the mechanical delay time of the mechanical shutter or the closing time of the mechanical shutter. Variations in exposure due to variations in operating characteristics can be reliably corrected.

  In one embodiment, the recording unit records the photoelectric conversion characteristics of the imaging element in addition to the operating characteristics of the mechanical shutter, and the adjustment unit includes the imaging element in addition to the operating characteristics of the mechanical shutter. The amplification factor of the amplifying unit is adjusted based on the photoelectric conversion characteristics.

  According to the imaging apparatus of this embodiment, the adjustment unit adjusts the amplification factor of the amplification unit based on the photoelectric conversion characteristics of the imaging element in addition to the operation characteristics of the mechanical shutter. In addition to characteristic fluctuations, sensitivity fluctuations of the image sensor can be adjusted simultaneously, and both exposure fluctuations and sensitivity fluctuations can be adjusted simultaneously.

Moreover, in the imaging device of one embodiment,
An optical system for forming the subject image on the image sensor;
A flexible wiring for supplying power to the mechanical shutter,
The flexible wiring has an identification symbol based on the operating characteristics of the mechanical shutter in a region optically separated from the optical system.

  According to the imaging apparatus of this embodiment, the flexible wiring has an identification symbol based on the operating characteristics of the mechanical shutter in a region optically separated from the optical system. When writing to the recording unit for each individual mechanical shutter, the imaging device can be reliably manufactured without mistakes, and the imaging device with excellent productivity can be obtained.

The imaging device of the present invention is
An image sensor for converting a subject image into an electrical signal;
An optical system for forming the subject image on the image sensor;
A mechanical shutter that blocks incident light to the imaging element and limits imaging time;
A flexible wiring for supplying power to the mechanical shutter,
The flexible wiring has an identification symbol based on an operating characteristic of the mechanical shutter in a region optically separated from the optical system.

  According to the imaging apparatus of the present invention, the flexible wiring has an identification symbol based on the operating characteristics of the mechanical shutter in a region optically separated from the optical system. The operating characteristics of the shutter can be identified, and an imaging device suitable for each mechanical shutter can be reliably and easily manufactured.

  According to the imaging apparatus of the present invention, since the adjustment unit that adjusts the amplification factor of the amplification unit based on the operation characteristic of the mechanical shutter recorded in the recording unit is provided, the operation of each mechanical shutter is operated individually. Variations in exposure due to characteristic variations can be easily corrected, and an image sensor with high image quality can be obtained.

  According to the imaging device of the present invention, the flexible wiring has an identification symbol based on the operating characteristics of the mechanical shutter in a region optically separated from the optical system. It is possible to reliably and easily produce an imaging apparatus suitable for each.

  Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments.

(First embodiment)
FIG. 1 is a simplified configuration diagram showing a first embodiment of an imaging apparatus according to the present invention. The imaging device 1 includes a lens unit 6, an imaging element unit 7, and control units 8 to 16.

  The image sensor unit 7 includes an image sensor 5. The image sensor 5 is, for example, a CCD or a CMOS, and converts the subject image into an electrical signal.

  The lens unit 6 includes imaging lenses 4a to 4c, a mechanical shutter 2, a diaphragm 3, and an imaging lens driving device (not shown).

  The imaging lenses 4 a to 4 c form a subject image on the imaging element 5. The imaging lenses 4a to 4c are moved in the optical axis direction by a drive input from the lens control unit 8, and the photographing optical system is zoomed or focused on the photographing magnification.

  The mechanical shutter 2 blocks incident light to the image sensor 5 and limits the imaging time. The diaphragm 3 adjusts the amount of light incident on the image sensor 5 by changing the aperture. The mechanical shutter 2 and the diaphragm 3 are controlled by a mechanical shutter / aperture controller 15 and are driven by a driving device (not shown) such as a motor.

  The image pickup device 5 is driven by the drive unit 9 based on the timing of the timing signal generation unit 10. The electric signal converted by the imaging element 5 is amplified through a gain adjusting unit 11 as an amplifying unit, and then processed by the video circuit unit 12. The charge accumulation time of the image sensor 5 is controlled by the electronic shutter controller 14.

  The operating characteristics of the mechanical shutter 2 are stored in a storage unit 13 as a recording unit. The operating characteristic of the mechanical shutter 2 is at least one of the mechanical delay time of the mechanical shutter 2 or the closing time of the mechanical shutter 2 as shown in FIG.

  Here, the “mechanical delay time of the mechanical shutter 2” refers to the time from when the mechanical shutter 2 starts to energize until the mechanical shutter 2 starts to block the aperture of the light beam incident on the image sensor 5. Of time. The “closing time of the mechanical shutter 2” means that the mechanical shutter 2 starts to shield the aperture of the light beam incident on the image sensor 5 and then the light beam of the incident light incident on the image sensor 5. The time required to completely shield the aperture.

  The operating characteristics of the mechanical shutter 2 vary from individual to individual, and the operating characteristics of the mechanical shutter 2 alone are measured before the lens unit 6 is assembled before the lens unit 6 is assembled. Later, it is recorded in the storage unit 13.

  The exposure controller 16 performs photometry to determine the exposure time. The exposure control unit 16 includes an adjustment unit 30 that adjusts the gain of the gain adjustment unit 11 based on the operating characteristics of the mechanical shutter 2 recorded in the storage unit 13. .

  The exposure control unit 16 controls the electronic shutter control unit 14 and the mechanical shutter / aperture control unit 15.

  Next, a method for correcting exposure time fluctuations by the imaging apparatus having the above configuration will be described.

  First, as shown in FIG. 2, when the body switch is turned on (step S1), the operating characteristics of the mechanical shutter 2 written in the storage unit 13 are read (step S2). When the release is turned on (step S3), the diaphragm 3 is set to a set value (step S4), photometry is performed (step S5), and the exposure time is determined by the exposure controller 16 (step S6).

  In this embodiment, internal photometry is performed to measure the amount of light from the subject incident on the image sensor 5 at a time prior to actual photographing. Of course, other methods can be used for the photometric method.

  Next, based on the exposure time and the operating characteristics of the mechanical shutter 2, a gain correction amount α from a standard amplification factor A is calculated (step S7), and the electronic shutter controller 14 opens the electronic shutter ( Step S8), the mechanical shutter 2 is closed according to the determined exposure time (Step S9). The signal photoelectrically changed by the imaging device 5 is amplified by the gain adjusting unit 11 (step S10). As the amplification factor at this time, a value (A × (1-α)) according to the gain correction amount is used.

  This gain correction amount α is positive when the closing operation of the mechanical shutter 2 is faster than the standard value, and is negative when it is late. Further, the gain correction amount α is determined based on the exposure time in the photographing state in addition to the time for closing the mechanical shutter 2. That is, when the exposure time is long, the absolute value of the gain correction amount α is small, and when the exposure time is short, the absolute value of the gain correction amount α is large. The relationship between the exposure time and the gain correction amount α is preferably stored in advance in a calculation unit (not shown).

  Therefore, the adjusting unit 30 adjusts the gain of the gain adjusting unit 11 based on the operating characteristics of the mechanical shutter 2 recorded in the storage unit 13. The fluctuation of the exposure amount due to the variation in the image quality can be easily corrected, and an image sensor with high image quality can be obtained.

  Since the operating characteristic of the mechanical shutter 2 is at least one of the mechanical delay time of the mechanical shutter 2 or the closing time of the mechanical shutter 2, the exposure due to variations in the operating characteristics of the individual mechanical shutters 2. The amount fluctuation can be corrected reliably.

  The operating characteristics of the mechanical shutter 2 are preferably both mechanical delay time and closing time. In particular, since the mechanical delay time is in a state where the aperture is fully open, the influence on the exposure amount is large, and it is preferable to correct this time fluctuation.

  As a configuration for changing the amplification factor in the gain adjusting unit 11, for example, a variable gain amplifier may be provided in the signal path of the imaging system, and the gain of this amplifier may be controlled.

  Note that the photoelectric conversion efficiency of the image sensor 5 is measured in advance, the storage unit 13 records the photoelectric conversion characteristics of the image sensor 5 in addition to the operating characteristics of the mechanical shutter 2, and the adjustment unit 30 The gain of the gain adjusting unit 11 may be adjusted based on the photoelectric conversion characteristics of the image sensor 5 in addition to the operating characteristics of the mechanical shutter 2.

  That is, when the operation characteristics of the mechanical shutter 2 are read, the photoelectric conversion efficiency of the image sensor 5 is read at the same time, and gain correction is performed based on both the operation characteristics of the mechanical shutter 2 and the photoelectric conversion efficiency of the image sensor 5. The quantity α is calculated. Therefore, in addition to the fluctuation of the operating characteristics of the mechanical shutter 2, the influence of the sensitivity fluctuation for each individual image pickup element 5 can be corrected, and an image pickup apparatus with higher image quality can be obtained.

(Second Embodiment)
FIG. 3 shows a second embodiment of the imaging apparatus of the present invention. In the second embodiment, a camera module of an imaging apparatus is shown. The camera module 17 includes the lens unit 6 and the image sensor unit 7 shown in FIG. 1, and the lens unit 6 and the image sensor unit 7 are coupled to each other.

  Inside the lens unit 6, the imaging lenses 4 b and 4 c, the mechanical shutter 2, and the diaphragm 3 of FIG. 1 are arranged. These optical systems 2, 3, 4 b, and 4 c are surrounded by a housing 20 and optically separated from the outside (in a state in which external light does not enter the optical system).

  The camera module 17 has a flexible wiring 18 (hereinafter referred to as a shutter FPC) that supplies power to the mechanical shutter 2. The shutter FPC 18 has an identification symbol 22 based on the operating characteristics of the mechanical shutter 2 in a region optically separated from the optical systems 2, 3, 4b, and 4c.

  Specifically, the shutter FPC 18 is for supplying an opening / closing signal (control signal) of the mechanical shutter 2 and is drawn out of the housing 20 from the drawer portion 24 of the housing 20. Yes. The shutter FPC 18 also serves as signal wiring of photo interrupters 19a and 19b for detecting the positions of the imaging lenses 4b and 4c.

  The camera module 17 includes a lens drive FPC 23 that supplies power to a drive motor that drives the imaging lenses 4b and 4c.

  The lens driving FPC 23 is provided with a first connector 21 a that is coupled to the wiring of the shutter FPC 18 and a second connector 21 b that is coupled to the signal wiring of the imaging element unit 7.

  An identification symbol 22 for identifying the operating characteristics of the mechanical shutter 2 is described in a portion of the shutter FPC 18 that is pulled out of the housing 20. By disposing the identification symbol 22 at a position visible from the outside of the camera module 17, it becomes easy to identify the solid shutter or the operating characteristic of the mechanical shutter 2, and based on the identification symbol 22, the storage unit 13 stores the above-described identification symbol 22. The operating characteristics of the mechanical shutter 2 are stored.

  As the identification symbol 22, a serial number indicating an individual of the mechanical shutter 2 or a symbol that classifies the operation characteristics of the mechanical shutter 2 into a plurality is used. The identification symbol 22 and the operation characteristic data of the mechanical shutter 2 are managed on a one-to-one basis and recorded in the storage unit 13.

  Therefore, by disposing the identification symbol 22 at a position where the shutter FPC 18 that is a part of the mechanical shutter 2 is visible from the outside of the camera module 17, there is a concern that the operating characteristic data of the mechanical shutter 2 may be mistakenly stored. In addition, data management becomes easy, productivity can be improved, and an inexpensive and high-performance imaging device can be obtained. In short, an imaging device suitable for each individual mechanical shutter 2 can be reliably and easily manufactured.

  The identification symbol 22 may be a bar code or the like other than numerical values and alphabets, and can be managed more easily by using a bar code or the like.

It is a simplified lineblock diagram showing a 1st embodiment of an imaging device of the present invention. It is a flowchart explaining correction | amendment of the exposure amount by the imaging device of this invention. It is a simplified perspective view which shows 2nd Embodiment of the imaging device of this invention. It is explanatory drawing explaining operation | movement of an electronic shutter and a mechanical shutter.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Imaging device 2 Mechanical shutter 3 Aperture 4a, 4b, 4c Imaging lens 5 Imaging element 6 Lens unit 7 Imaging element unit 8 Lens control part 9 Drive part 10 Timing signal generation part 11 Gain adjustment part (amplification part)
12 Video circuit section 13 Storage section (recording section)
14 Electronic Shutter Control Unit 15 Mechanical Shutter / Aperture Control Unit 16 Exposure Control Unit 17 Camera Module 18 Shutter FPC (Flexible Wiring)
19a, 19b Photo interrupter 20 Housing 21a, 21b Connector 22 Identification symbol 23 Lens drive FPC
24 drawer part 30 adjustment part

Claims (4)

An image sensor for converting a subject image into an electrical signal;
A mechanical shutter that blocks incident light to the imaging element and limits imaging time;
An amplifier for amplifying the electrical signal converted by the imaging device;
A recording unit for recording operating characteristics of the mechanical shutter;
An image pickup apparatus comprising: an adjustment unit that adjusts an amplification factor of the amplification unit based on an operation characteristic of the mechanical shutter recorded in the recording unit. The imaging device according to claim 1,
The operating characteristic of the mechanical shutter is at least one of a mechanical delay time of the mechanical shutter or a closing time of the mechanical shutter. The imaging device according to claim 1 or 2,
The recording unit records the photoelectric conversion characteristics of the imaging element in addition to the operating characteristics of the mechanical shutter,
The adjustment unit adjusts an amplification factor of the amplification unit based on a photoelectric conversion characteristic of the imaging element in addition to an operation characteristic of the mechanical shutter. An image sensor for converting a subject image into an electrical signal;
An optical system for forming the subject image on the image sensor;
A mechanical shutter that blocks incident light to the imaging element and limits imaging time;
A flexible wiring for supplying power to the mechanical shutter,
The imaging apparatus according to claim 1, wherein the flexible wiring has an identification symbol based on an operating characteristic of the mechanical shutter in a region optically separated from the optical system.

Images