JPS6364013A - Solid-state image pickup device - Google Patents

Abstract

PURPOSE:To improve S/N by switching a solid-state image pickup element and a focus detecting element, which detects the in-focus state of an object image on said element, in a set position to make the sufficient quantity of light incident on the solid-image pickup element at the time of photographing. CONSTITUTION:A printed circuit board 9 having a CCD8 and a printed circuit board 11 having a focus detecting element 10 are placed and fixed on plane parts 7a and 7b of a rotating plate 7 respectively. An optical path dividing prism 19 is fixed to the element 10 to form the optical path to a light receiving face 10a of the element 10 which coincides with an optical axis 6 and the optical path to a finder part A. When an image pickup start button is depressed, the element 10 receives the object light to detect the focus, and a focusing lens is moved to the focus position by the output. Power is supplied to a rotary solenoid 14 by a completion of this operation, and an arm 15 is turned counterclockwise at 90 deg.. Thus, the plane part 7a (or 7b) is set to the vertical (or horizontal) state as shown in a figure (b), and the CCD8 goes onto the optical axis instead of the element 10 and the prism 9, and the element 10 and the prism 19 are drawn back from then optical axis 6.

Description

[Detailed Description of the Invention] [Industrial Field of Application] This invention relates to a solid-state imaging device, and more specifically, to a solid-state imaging device, which detects focus of a subject image with a focus detection element, and records the subject image by photoelectrically converting it with the solid-state imaging device. The present invention relates to solid-state imaging devices such as video cameras and electronic still cameras equipped with an autofocus function.

[Prior Art] Generally, a video camera equipped with an autofocus function has 1. as shown in FIG. 'i 5-1j, and the focus lens 101. zoom lens 10
2. The subject light flux that has passed through the fixed lens 103 is split into two by an optical path splitting prism 104, and one of the light fluxes is sent to an aperture 105 as imaging light. It passes through a relay lens 106 and a low-pass filter 107 and is imaged on the imaging surface of a solid-state image sensor 108, and the other light beam is used as observation light exclusively for the finder optical system and passes through the mirror 109 and imaging lens 110 to a focus detection element. 111. Then, the focus state Iha number from this focus detection element 111 is calculated by the calculation control unit 1.
12, and operation 1. '! The I control section 112 performs calculations on this focus state signal, the zoom lens information from the zoom encoder 113, and the focus lens position information from the focus lens encoder 114.
The autofocus motor 115 is moved to the focusing position.

[Problems to be Solved by the Invention] However, in solid-state imaging devices such as video cameras in which a portion of the incident light is always guided to the finder optical system by the optical path splitting prism 104, etc., the solid-state imaging device Since the amount of light guided as imaging light to the solid-state image sensor 108 is reduced, the S/N of the signal obtained from the solid-state image sensor 108 is not good.

This invention was made in view of these problems, and provides a solid-state imaging device that enables focus detection and allows a sufficient amount of light to enter the solid-state imaging device during shooting to improve S/N. The purpose is to provide.

[Means and effects for solving the problems] The solid-state imaging device of the present invention includes a solid-state imaging device for photoelectrically converting a subject image that has passed through a photographing lens, and a subject image formed on the solid-state imaging device. The arrangement position of the focus detection element for detecting the in-focus state of the solid-state imaging probe is switched by a switching means. is retracted from the imaging position, and during photographing, the solid-state image sensor is placed at the imaging position and the focus detection element is retracted from the optical path.

[Embodiment] FIG. 1 is a longitudinal sectional side view of an embodiment of an electronic camera which is a solid-state imaging device of the present invention, and FIG.
It is a longitudinal sectional front view along the line -■. This electronic camera's first
．． The state shown in FIG. 2 is the normal state before photographing.

In Figures 1 and 2, inside the camera body 1, there is a metal plate, etc., which is approximately U-shaped when viewed from the front, behind the photographic optical system consisting of an afocal lens group 2, an aperture 3, and a relay lens group 4. A frame 5 formed by bending is provided. The central bottom portion of the frame 5 is fixed to the bottom surface of the camera body 1 by a fixing means (not shown), and both the left and right vertically rising sides reach a position sufficiently higher than the height position of the photographing optical axis 6. A rotating plate 7 is attached between the left and right sides of the frame 5. This rotating plate 7 has two flat plate parts 7a and 7b bent at right angles,
A printed circuit board 9 having a CCD (electronic 6:I coupling device) 8, which is a solid-state imaging device, is placed and fixed on one of the hair follicles 7a having a large area, and on the other flat plate portion 7b having a relatively small area. is a printed circuit board 11 having a focus detection element 10
is placed and fixed. 20 Support pieces 7c and 7d protrude on both sides of the surface opposite to the surface having the CCD 8 at a position close to the flat plate portion 7b of the flat plate portion 7a of the rotating plate 7.
is formed, and the supporting piece 7c is formed.

7d is rotatably supported on both left and right sides of the frame 5 by pivot pins 12 and 13, so that it can rotate relative to the frame 5! 27 is rotatable. Further, a protrusion piece 7e is formed on the same side of the rotary plate 7 as the support piece 7d and at a position away from the flat plate part 7b, and the protrusion piece 7e is provided on the arm 15 driven by the rotary solenoid 14. The arm pin i5a passes through an arc-shaped long hole 5a provided in the frame 5 and is rotatably connected to the arm pin i5a.

The main body of the rotary lenoid 14 has a cylindrical shape as shown in FIG. 3, and a mounting portion 14 a provided at one end thereof.
At 14b, it is attached to one rising edge of the frame 5 from its outer surface with a screw 16.

The drive shaft 14c of the rotary lenoid 14 is fixed to the base end of the arm 15, and the arm bin 15a is formed at the distal end of the arm 15. A spiral return spring 17 is disposed on the drive shaft 14c of the rotary solenoid 14 and is stretched between the drive shaft 14c and the rotary solenoid body.
For this reason, the arm 15 is always given the habit of rotating in the counterclockwise direction shown by arrow a. This rotorinoid 14
When energized, the electromagnetic action causes the drive shaft 14c to
The arm 15, which is integral with the arm 15, rotates in the clockwise direction indicated by the arrow against the rotational behavior of the return spring 17.

The drive shaft 14c of the rotary solenoid 14 is coaxial with a pivot pin 12.13 that supports the rotary plate 7 in the frame 5. During normal life, the arm pin 15a is at the same height as the pivot pin 1 due to the rotational behavior of the arm 15.
2.13 and the rotating plate 7 is located at the same height as the flat plate part 7.
a comes into contact with a stopper pin 5b installed in the frame 5 to keep it horizontal, and further rotation in the counterclockwise direction is restricted. Therefore, in this state, the other flat plate part 7b is maintained vertically, and the light receiving surface 10a of the focus detection element 10 disposed on the flat plate part 7b is located on the photographing optical axis 6. The CCD 8 on one of the flat plate parts 7a is connected to the flat plate part 7a.
It is located at the rear position of b, that is, at a position evacuated from the photographing optical path.

Note that a low-pass filter 18 made of a crystal filter or the like for moire prevention is fixed to the CCD 8, and the focus detection element 1
At 0, an optical path splitting prism 19 is fixed.

At this position, the optical path splitting prism 19, which is disposed on the photographing optical axis 6 together with the focus detection element, is placed on the photographing optical axis 6.
The optical path is divided into two parts: a focus detection optical path that goes toward the light receiving surface 10a of the focus detection device 10, and an observation optical path that is perpendicular to the optical path and goes toward the finder section. The light traveling along this observation optical path is reflected by a finder mirror 21, passes through an eyepiece 22 and an eyecup 23 provided in a viewing window, and enters the photographer's eye 24.

Here, when the photographer aligns the electronic camera with the cube and presses a shooting start button (not shown), the electronic camera is first in the state shown in FIG. The child 10 receives object light and performs focus detection. A focus state signal, which is the output of the focus detection element 10, is guided to an electric circuit (not shown) and subjected to signal processing. This signal processing output drives an autofocus motor (not shown) to move the focus lens to the in-focus position.

When this autofocus operation is completed, the rotary solenoid 14 becomes energized, and the arm 15 rotates in the direction of the arrow shown in FIG. The rotating plate 7 moves 90° counterclockwise in FIG. 1 around the pivot pin 12.13.
Rotate. Then, with the rotating plate 7 rotated 90 degrees,
As shown in FIG. 4, the flat plate portion 7a comes into contact with a stopper pin 5C provided integrally with the frame 5, and further rotation is restricted and stopped. In the state shown in FIG. 4, the flat plate portion 7a is placed vertically, and the flat plate portion 7b is placed horizontally. At this time, the CCD 8 and the low-pass filter 18 fixed to the flat plate part 7a are connected to the focus detection element 1.
0 and the optical path splitting prism 19, a focusing detection probe 1 extends onto the photographing optical axis 6 and is fixed to the flat plate portion 7b.
0 and the optical path splitting prism 19 are retracted from above the photographing optical axis 6. In this state, from the rear end of relay lens group 4,
The back focus 1 from the light receiving surface 8a of the lens 8 is the back focus 2 from the rear end of the relay lens group 4 to the light receiving surface 7a of the focus detecting element 7 in the state shown in FIG.
is equal to

Therefore, when photographing is performed when the state shown in FIG. 4 is stabilized, the photographed image that is taken out as an electrical signal from the CCD 8 and recorded in a recording device (not shown) will be in focus. In this case, all of the subject light that has passed through the afocal lens group 2 and the relay lens group 4 and entered the camera body 1 is received by the CCD 8 as photographing light, so the amount of incident subject light can be adjusted to the maximum. It is used for photographing, and the S/N ratio is significantly improved.

In addition, in the photographing state shown in FIG. 4, the rotating plate 7
Since the flat plate portion 7b is located above the CCD 8 and the low-pass filter 18, the eyepiece lens 22 is
Even if external light enters the finder section through the CCD 8, this external light is blocked by the flat plate section 7b and does not reach the CCD 8.

When the photographing is completed, the power supply to the rotary solenoid 14 is cut off, so that the arm 15 rotates in the direction of arrow a due to its rotational behavior, and the rotation plate 7 and the CCD 8 . The focus detection element 10 etc. are moved from the position shown in FIG.
The electronic camera returns to the initial position shown in FIG. 2, and returns to the ready state for the next photographing.

FIG. 5 is a longitudinal sectional side view of another embodiment of the electronic camera, FIG. 6 is a longitudinal sectional front view along the vt-vt line in FIG. 5, and FIG. FIG. The state of this electronic camera shown in FIGS. 5 to 7 is the state at the time of photographing.

In FIGS. 5 to 7, an optical path splitting prism 59 is fixed to the camera body 41 behind the relay lens group, and a low-pass filter 58 is fixed to the rear end surface of the prism 59. Therefore, the afocal lens group 2. The light flux passing through the photographing optical axis 6 of the aperture 3 and the relay lens group 4 always reaches the optical path splitting prism 59, where the optical path is divided into two.
One of the light beams is configured to further pass through a low-pass filter 58 as photographing light. The light beam reflected by the optical path splitting prism 59 and directed vertically upward becomes observation light.

A support shaft 52 is fixed to the inner wall of the back plate of the camera body 41,
A rotating plate 47 is rotatably supported on the support shaft 52.

This rotating plate 47 is formed by a flat plate part 47a having a surface perpendicular to the photographing optical axis 6 and rotating in the same direction, and a part of this flat plate part 47a being bent forward parallel to the optical axis 6 at a right angle. It is formed by a light shielding part 47c. A printed circuit board 51 having a CCD 48 and a focus detection probe 50 is mounted and fixed on the front surface of the flat plate portion 47a. The CCD 43 and the focus detection probe 50 are placed apart from each other by a certain angle around the light receiving surfaces 48a and 50a or the support shaft 52, that is, by the rotation angle of the arm 55 by the rotary solenoid 54, which will be described next. It becomes.

An arm 55 connected to the rotary solenoid 54 and its drive shaft 54c (not shown in FIG. 5)
is constructed almost the same as the rotary solenoid 14 and arm 15 shown in FIG. 3, and is not shown. (The return spring causes the arm 55 to always rotate in the opposite direction to the rotation direction of the rotary solenoid 54 when the rotary solenoid 54 passes. The arm pin 55a at the tip of the arm 55 is fixed to the inner wall of the side plate of the camera body 41 by a squared plate 45 in a state in which
is connected to the rotating plate 47. When the rotary solenoid 54 is not energized, the arm 55 rotates clockwise when viewed from the front of the camera due to its rotational behavior.
For this reason, the rotating plate 47 is in a rotating position as shown in FIG. 8, and is positioned and stopped by a stopper (not shown).

In the state shown in FIG. 8, the light receiving surface 50 of the focus detection element 50
A is located behind the low-pass filter 58, and can receive the light beam passing through the photographing optical axis 6. That is, in normal times before photographing, this electronic camera is in the state shown in FIG.

Now, when you point this electronic camera at the subject and press the shooting start button (not shown), the focus detection probe 50 receives the light from the subject and focuses the image in the state shown in Figure 8. Perform detection. When the autofocus motor is driven by the output of the focus detection element 50 and the focus lens is moved to the in-focus position, the rotary solenoid 54 is energized and the arm 55 moves the rotary plate 47 as shown in FIG. Rotate counterclockwise. As shown in FIGS. 5 to 7, when the rotating plate 47 reaches a rotational position behind the light receiving section 48a of the CCD 48 or the low-pass filter 58 where it can receive the light flux passing through the photographing light 1d16, the rotating plate 47 moves to a stopper (not shown). It is positioned and stopped. As the rotating plate 47 rotates, the CCD 48 enters and is placed on the photographing optical axis 6, and the focus detection element 50 is retracted to a position away from the photographing optical axis 6. Photographing is then performed in this state. The CCD 48 and the focus detection element 50 are the same.
- It is arranged on the plate part 47a, and its position is changed by rotation of the flat plate part 47a in the plane direction, so that the light-receiving surface 48a of the CCD 48 and the light-receiving surface 50a of the focus detection element 50 are the same. If it is on the plane of Therefore, in-focus photography is performed.

Furthermore, in the case where the CCD 4g is positioned on the photographing optical axis S in a rotating manner, the light shielding portion 4 of the rotating plate 47 is
7c is a CCD 48.7c arranged on the photographing optical axis 61.
Since it covers the upper part of the low-pass filter 58 and the optical path splitting prism 59, even if external light is incident on the finder section through the eyepiece lens 22, it blocks this external light and prevents it from entering the CCD 4g. At the same time, the observation light guided from the optical path splitting prism 59 to the finder section is also blocked, and the light flux passing through the photographing optical axis 6 is efficiently <CC
I try to be guided by D4g.

The electronic camera of this embodiment switches the positions of the CCD 48 and the focus detection element 50 by moving them in a plane perpendicular to the photographing optical axis 6, as shown in FIGS. 1 to 4 above. Compared to the electronic camera of the above embodiment, the depth dimension of the camera body can be reduced and the camera body can be configured to be thin. Also, a low pass filter 58. Since the optical path splitting prism 59 is fixed to the camera body 41, the weight of the movable part is lightened and rapid switching of movements can be performed.

The solid-state imaging device of the present invention can also be applied to an active type autofocus system using infrared light.

Next, an example applied to such an autofocus system will be described.

As shown in FIG. 9, an infrared light emitting diode (hereinafter referred to as an infrared LED) 73 is located on the electronic camera body 71 at a base line distance t from the optical axis 76 of the photographing lens 72. A collimator lens 74 is provided to convert the emitted infrared light into a parallel beam of light, and the infrared light projected from the collimator lens 74 toward a subject 75 is reflected by the subject 75 and then passes through the photographing lens 72. The light enters a focus detection element 80 (see FIG. 10.11) on a rotary plate 77 rotatably provided on the camera body 71. As is well known, the distance to the subject 75 is determined according to the incident position of the infrared reflected light on the focus detection element 80 using the bigonal and IPj quantity methods.

As shown in FIG. 10, the rotating plate 77 is rotatably provided on the inner wall of the rear plate of the camera body 71 by a support shaft 82 (see FIG. 9), similar to the rotating plate 47 in the second embodiment. It consists of a flat plate part 77a perpendicular to the optical axis 76 and a light shielding part 77c formed by bending a part of the flat plate part 77a into a right-angled shape. This rotating plate 77 is connected to an arm 85 which is always given a clockwise rotating habit in FIG. 10 by a rotary solenoid 84 fixed to the camera body 71 by a mounting plate 79. Rotation! A package 86 containing a focus detecting element 80 and a CCD 7g which is a solid-state imaging element is fixed on the flat plate part 77a of 277. That is, as shown in FIG. 11 showing an enlarged cross section of the package 86, the package 86
A monolithic substrate 87 in which the CCDL 8 and a focus detection element 80 consisting of a line sensor or the like are integrally formed on the same surface is disposed in the space inside the lens 6. The space of the package 86 in which the monolithic substrate 87 is disposed is surrounded by a protective glass consisting of an infrared cut filter 88 and a band pass filter 89.

The infrared cut filter 88 facing the CCD 78 is C
A band pass filter 89 is provided to allow only visible light to enter the CD 78 and not allow infrared light for focus detection to pass through. It allows the outside light band to pass through. The infrared light that has passed through the bandpass filter 89 is transmitted to the CCD
An infrared cut filter 88 and a bandpass filter 8 are installed in the space of the package 86 to prevent the light from entering the
A light shielding member 83 is integrally provided at the boundary portion of 9.

Under normal conditions, the infrared reflected light that has passed through the shooting target shaft 76 is incident on the focus detection element 80 on the flat plate portion 77a, which is fully rotated clockwise, so by pressing the shooting start button,
In this state, the focus detection operation is performed, and when the focus detection operation is completed, the rotating plate 77 rotates counterclockwise in FIG. 10, and the CCD 7g is positioned on the photographing optical axis. Photography will take place. When the shooting is finished, the rotating plate 77
rotates back clockwise, and the focus detecting element 80 is positioned on the photographing optical axis.

Note that the configuration in which the solid-state imaging probe and the 6° detection device are formed on the same monolithic substrate as in the above embodiments is as follows.
It goes without saying that this invention is not only applicable to active type autofocus systems that use infrared light for IQ. That is, even in a pudge-eve type autofocus system that detects the in-focus state from the blurred state or phase shift of the subject image, it can be configured as shown in FIG. 12.

In FIG. 12, a monolithic substrate 97 on which a CCD 78 and a focus detection device 90 are integrally formed on the same surface is placed in a space of a package 96, and the space is a protective sheet consisting of an infrared cut filter 98. covered by glass. This infrared cut filter 98 is for preventing blooming and smear phenomena by canting infrared light contained in the subject image. CCD78 in this example
It goes without saying that the movement of the focus detection element 90 toward and away from the photographing optical axis is performed in exactly the same manner as in the previous embodiment.

[Effects of the Invention] As described above, according to the present invention, when the focus detection element is performing focus detection, the solid-state image sensor is placed in a retracted position from the imaging surface position, and the object image is When the image is photoelectrically converted by the solid-state imaging element, the focus detection element is placed in a position retracted from the imaging surface, so the amount of light from the subject that passes through the photographic lens (11) increases. , the S/N improves significantly.

[Brief explanation of drawings]

1 is a longitudinal sectional side view of a solid-state imaging device showing an embodiment of the present invention during normal operation; FIG. 2 is a longitudinal sectional front view taken along the line ■-■ in the if diagram; FIG. FIG. 4 is a perspective view of a rotary solenoid used in the solid-state imaging device shown in FIG. 1, FIG. 4 is a longitudinal cross-sectional side view of the solid-state imaging device shown in FIG. FIG. 6 is a longitudinal sectional side view of a solid-state imaging device during imaging, showing an example; FIG. 6 is a longitudinal sectional front view taken along the line vt-vt in FIG. 5; and FIG. FIG. 8 is a longitudinal sectional front view of the solid-state imaging device shown in FIG. 5 in a normal state, and FIG. 9 is a schematic side view of a solid-state imaging device showing still another embodiment of the present invention. , FIG. 10 is a front view of the main part in FIG. 9, FIG. 11 is an enlarged sectional view taken along the line XI-XI in FIG. 10, and FIG. 12 is another embodiment of the present invention. In the example above, the first
FIG. 13 is an enlarged sectional view showing a main part of a configuration similar to the configuration in FIG. 1. FIG. 13 is a schematic diagram showing the configuration of an example of a conventional solid-state imaging device. 7.47.77... Rotating plate (switching means) 8.4
8.78...COD (solid-state image sensor)10.
50, 80.90... Focus detection element 14.54
．． 84...Rotary solenoid (switching means) 15.55.85...Arm (switching means) 2 also 3- base 4 days base 5 leap one ■ -9 difference phantom 1 ■ force 13 lo

Claims (1)

[Claims] A solid-state image sensor that photoelectrically converts a subject image formed on an imaging surface by a photographic lens, and detects the in-focus state of the subject image formed on the imaging surface of this solid-state image sensor. a focus detection element for detecting a focus; when detecting focus, the focus detection element is placed on the optical path and the solid-state imaging device is retracted from the imaging position; when photographing, the solid-state imaging device is placed at the imaging position; A solid-state imaging device comprising: switching means for retracting a focus detection element from an optical path.