JPH04156186A - Image pickup device - Google Patents

Abstract

PURPOSE:To realize a thin structive camera provided with an ultra-thin image pickup optical system useful for a digital electronic camera by providing a 1st reflecting mirror reflecting a light in a direction orthogonal to an optical axis of a picked-up picture and a 2nd reflecting mirror reflecting a light in a direction orthogonal to an optical axis of the reflected light to the device. CONSTITUTION:An optical low pass filter of reflection type phase grating is provided to a reflection face of a 1st reflecting mirror 9. The optical low pass filter is a reflection type phase grating whose reflecting face is formed by plating a material such as an aluminum to an acrylic resin processing material. The 1st reflecting mirror 9 acts like the reflection type phase grating and uses a reflecting face and a low pass filter in common to offer features in thin profile and small size. A 2nd reflecting mirror 13 consists of an infrared ray cut-filter 13b and a reflecting mirror surface 13c, and the 2nd reflecting mirror 13 acts like the infrared ray cut-filter and uses a reflecting face and a infrared ray cut-filter in common to offer features in thin structure and small size. Thus, the entire device is made thin in the profile.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a photographing device such as an electronic still camera, and more particularly to a photographing device having a thin optical system.

(Prior Art) In recent years, in the field of electronic still cameras, so-called digital electronic still cameras have been developed that record video information on a card-shaped thin memory (hereinafter simply referred to as a memory card).

In the case of this digital electronic still camera, the memory card used for recording is thin, and unlike electronic still cameras that use conventional floppy disks, it does not have complex mechanisms such as the floppy disk drive and recording mechanism. Since it is unnecessary, it can be made thinner. Therefore, it is expected that it will have potential as a thin information storage/processing device such as a so-called electronic notebook.

(Object of the Invention) Therefore, an object of the present invention is to provide a thin camera equipped with an ultra-thin photographic optical system useful for making digital electronic cameras thinner.

(Structure of the Invention) In order to achieve the above object, the present invention includes a first reflecting mirror that reflects an incident photographed image in a direction perpendicular to the optical axis of the photographed image; a second reflecting mirror that reflects the reflected light in a direction perpendicular to the optical axis of the reflected light;
A photographing element that receives the reflected light reflected by the second reflecting mirror and outputs an electrical signal related to the incident light; a shutter that allows the reflected light to pass through the photographing element for a predetermined period of time; and a photographing lens that is located between the first reflecting mirror and the second reflecting mirror and forms an incident photographic image on the photographing element. A photographic device characterized by: It is characterized in that the reflecting surface on either side of the first reflecting mirror or the second reflecting mirror is a reflective phase grating.

Further, the present invention is characterized in that an infrared cut filter is formed on the reflecting surface of either the first reflecting mirror or the second reflecting mirror.

Further, the shutter is composed of a rotatable disc in front of the photographing element and a hole provided in the disc, and the exposure time is determined by the time it takes for the chain hole to pass through the front of the photographing element. It is characterized by

The shutter is composed of a rotatable disk in front of the photographing element, a hole provided in the disk, and a fixed diaphragm provided on the optical axis. A feature is that the amount of light incident on the element is adjusted.

Hereinafter, the present invention will be explained in detail based on the embodiments shown in FIGS. 1 to 6.

FIG. 1 is an optical system layout diagram showing an embodiment.

In FIG. 1, the photographing lens 1 has an open F number of 2.8.
is set to This photographing lens element can be moved in the optical axis direction by manually moving the slide mechanism 3, and the focus can be adjusted. A hole 3a provided at one end of the slide mechanism 3
The ball 3b and the spring 3c are fitted into the four conical holes 5a made on the surface of the fixing member 5.
A positioning mechanism is configured in which the position is determined by being pressed by the force of the spring 3c.

The positions of the four conical holes 5a cover the photographing distance from short distance to infinity.

The aperture 7 is a fixed aperture whose diameter does not change, and the aperture 7 is a fixed aperture that does not change in diameter.
It is placed in front of.

The reflection surface of the first reflection 119 is provided with an optical low-pass filter of a rectangular or triangular wave reflection type phase grating as shown in the cross-sectional views of FIGS. 2 and 3. This optical low-pass filter is a reflective phase grating made of, for example, an acrylic resin molded or processed into a rectangular or triangular wave shape and plated with, for example, aluminum to form a reflective surface.

Conventionally, as a method for obtaining color signals, for example, in a single-chip still camera in which a color separation filter is disposed in close contact with the image sensor 11, there is an object whose spatial frequency corresponds to the pitch of each color of the color separation filter. In some cases, it is known that false colors appear in the reproduced image. In order to remove this false color, an optical low-pass filter is inserted into the imaging optical system to reduce and remove spatial frequency components equal to or higher than the pitch of each color.

Further, although crystal is generally used as an optical low-pass filter, an inexpensive and thin phase grating type low-pass filter is used instead. That is, by allowing the first reflection 119 to function as a reflective phase grating and serving both as a reflective surface and a low-pass filter, it is advantageous for thinning and downsizing.

Second reflection! The structure of the second reflecting mirror 13, whose detailed side view is shown in FIG. 5 and its perspective view is shown in FIG. It consists of The infrared cut filter 13.b is necessary because the sensitivity characteristics of the image pickup device 11, such as a CDD, extend into the infrared region, and in this embodiment, CM500 manufactured by HOYA is used. In addition, one surface, that is, the surface in contact with the rear cover glass, is plated with aluminum or the like to form a reflective mirror surface 13c.
form.

In addition, in order to increase the moisture resistance of the material CM50o of the infrared cut filter 13b, the infrared cut filter 13b is sandwiched between the front cover glass 13a and the rear cover glass 13d, and moisture-proof coating is applied to the side surfaces of the infrared cut filter 13b. The thickness of the infrared cut filter 13b is generally required to be 1ffiI11, but by reflecting the light beam on the reflective mirror surface 13c and passing the infrared cut filter 13b twice, the thickness of the infrared cut filter 13b can be reduced to half, 0.5+IIm. It can be done.

The circular shirt plate 15 is attached to the shaft 17a of the motor 17.

A top view of the mechanism of this shutter section is shown in FIG.

The sensors 19a and 19b are provided on the shirt plate 15.
By detecting the two slit holes 15a and 15b, the shirt shirt plate 1
5 is detected optically, for example. Two of them are arranged at an angle of 120 degrees around the shaft 17a of the motor 17.

The holes 15c, 15d, and 15e are holes drilled in the shirt shirt plate 15, and three holes are each arranged at an angle of 120°. When one of the holes 15c, 15d, and 15e is positioned above the imaging surface 11a of the image sensor 11 by the rotation of the motor 17, it is exposed above the imaging surface 11a, and between the holes 15c, 15d, and 15e. The non-aperture part is the imaging surface 1
When placed above 1a, it is shielded from light.

Further, although the hole 15c is a hole, ND filters 21d and 21e are arranged in the holes 15d and 15e, respectively.
The intensity of the passing light beam is attenuated. The aperture 7 and the ND filters 21d and 21e constitute a light amount adjusting means for adjusting the amount of light.

The ND filter 21d reduces the passing light flux to 1/4, and N
The D filter 21e is set to 1/16.

That is, when the hole 15c is placed, the F number (aperture value)
is 2.8, and when the ND filter 21d is placed, it is 5.6.
, 11 when the ND filter 21e is arranged.

Further, the exposure time is determined by rotating the shutter plate 15 by the motor 17 so that one of the holes 15c, 15d, and 15e is placed on the imaging surface 1.
1 determined by the time it passes over 1a, for example, FNo.
= 5.6 and 1/250 second exposure, as shown in FIG. It is made to pass over the imaging surface 11a. At that time, hole 15d
The time it takes for the light to pass through the imaging surface 11a may be set to 1/250 second. The rotational position of the shirt flap plate 15 is determined by detecting the slit holes 15a, 15b with the two sensors 19a, 19b, so that the openings 15c, 15 are located above the imaging surface 11a.
Since it is possible to detect which one of F numbers d and 15e is located, the above three types of F numbers 2.8.5.6
．． You can arbitrarily choose one of the 11. Again, the first
Referring to the figure, the wiring support board 23 includes the image sensor 17,
The motor 11 and the sensors 19a, 19b are arranged and supported, and the wiring between them is performed. Exterior 2
5 houses the mechanism described above. The cover glass 27 is a transparent cover glass that covers the openings 1), (2), and (3) through which the photographing light beam 29 passes. The flash 33 emits auxiliary light for photographing.

By arranging the components as described above, it is possible to obtain a camera having an ultra-thin optical system.

(Effects of the Invention) As described above, according to the present invention, the overall thickness of the optical system can be reduced by configuring the optical system in relation to its surroundings as described above. - Also, by giving the first reflecting mirror the role of a reflective phase grating and serving both as a reflecting surface and a low-pass filter, it is advantageous for thinning and downsizing.

By giving the second reflecting mirror the role of an infrared cut filter and serving both the reflective surface and the infrared cut filter, the
It is advantageous for miniaturization, and by reflecting the light beam on a reflective mirror surface and passing it through the infrared cut filter, the infrared cut filter can be made half the thickness of a normal infrared cut filter, which is advantageous for thinning and miniaturization. becomes.

The diaphragm is a fixed diaphragm, and a plurality of ND filters are respectively provided in a plurality of apertures provided in a rotating circular diaphragm plate as a light amount adjustment means, and the exposure time is determined by the time it takes for the aperture to pass through the imaging surface. It is mechanically simple, and is advantageous for thinning and downsizing.

[Brief explanation of the drawing]

FIG. 1 is a diagram for explaining the configuration of the optical system of the present invention, FIGS. 2 and 3 are diagrams showing the configuration of the reflecting surface of the first reflecting mirror shown in FIG. 1, and FIG. 4 is a diagram for explaining the configuration of the optical system of the invention. Figure 5 showing the configuration of
This figure is a diagram showing the configuration of the second reflecting mirror shown in FIG. 1, and FIG. 6 is a perspective view of the second reflecting mirror. 1... Imaging lens, 9... First reflecting mirror, 11...-imaging element, 13... Second
Reflector, 15...Shattata board. Patent applicant Ricoh Co., Ltd. JP-A-4-1s61st; (5) Figure 3

Claims (5)

[Claims] (1) A first reflecting mirror that reflects an incident photographed image in a direction perpendicular to the optical axis of the photographed image, and a reflected light reflected by this first reflecting mirror that is perpendicular to the optical axis of the reflected light. a second reflecting mirror that reflects the light in a direction to a shutter disposed between the mirror and the second reflecting mirror and allowing the reflected light reflected by the second reflecting mirror to pass through the photographing element for a predetermined time;
What is claimed is: 1. A photographing device comprising: a photographing lens located between a reflecting mirror and a photographing lens that forms an incident photographic image on a photographing element. (2) The photographing device according to claim 1, wherein a reflecting surface on either one of the first reflecting mirror and the second reflecting mirror is a reflective phase grating. (3) The photographing device according to claim (1) or (2), characterized in that an infrared cut filter is formed on a reflective surface on one side of the first reflecting mirror and the second reflecting mirror. . (4) The shutter is composed of a rotatable disc in front of the photographing element and a hole provided in this disc, and the exposure time is determined by the time it takes for the hole to pass through the front of the photographing element. The imaging device according to claim (1), (2) or (3), characterized in that: (5) The shutter is composed of a rotatable disk in front of the photographing element, a hole provided in this disk, and a fixed diaphragm provided on the optical axis, and the amount of light passing through the hole is determined by the amount of light passing through the hole. Claims (1), (2), (3) or (2) characterized in that the amount of light incident on the photographing element is adjusted.
The photographing device described in 4).