JP2003029166A - Adapter for imaging - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a simple and low-cost adapter for imaging which is used for a microscope or the like, without using a field lens. SOLUTION: An eyepiece and a camera lens are arranged, and emitted luminous flux from the eyepiece is set parallel, and the exit pupil of the eyepiece and the entrance pupil of the camera lens are nearly aligned with each other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adapter for inserting a microscope or a telescope into a lens barrel to take a microscope image or a telescope image with a CCD camera or a CMOS camera. INDUSTRIAL APPLICABILITY The present invention is used for an image pickup device attached to a microscope image pickup device, a telescope image pickup device, or another optical system measurement device.

[0002]

2. Description of the Related Art An image obtained by a microscope is directly used for CCD
2. Description of the Related Art A device is known in which an image is taken by a camera or a CMOS camera and is taken into a computer for image processing, or is displayed on a display device for observation. As the image pickup device, there are a CCD camera device for taking a moving image and a digital camera device for taking a still image, and such an image pickup device is attached to a lens barrel of a microscope through an adapter.

As such an adapter, Japanese Patent Laid-Open No. 2001-100105 discloses an adapter for easily inserting an image into an eyepiece portion for human observation to perform imaging.

[0004]

A lens of a conventional adapter for an image pickup device uses a relay lens in the adapter so that the image of the microscope objective lens is directly formed on the CCD image pickup surface by the relay lens. .

FIG. 4 shows the configuration of this conventional lens system.

A relay lens forms an image on the CCD image pickup surface of the CCD image pickup section. In order to form an image on this CCD image pickup surface, a field lens is arranged near the image formation surface (position where the reticle is inserted) of the microscope objective lens, and the light beam from the objective lens is folded along the optical axis. The lens system is designed so that the generated light beam is projected onto the CCD image pickup surface by the relay lens.

By the way, when the above-mentioned adapter is inserted into the eyepiece lens section instead of the eyepiece lens, the field lens is close to the image plane of the objective lens, for example, a mirror because the outer diameter is small and the image is better formed on the relay lens. It must be placed 10 mm in front of the tube.

Therefore, in the conventional adapter, when the lens is designed, it is necessary to dispose the field lens in front of the image plane of the microscope, so that the reticle cannot be inserted and the adapter length becomes long. Moreover, it is necessary to design a new lens system, and the conventional eyepiece cannot be used as it is.

Further, when the lens system of a normal digital camera is directly connected to the eyepiece lens, even if an adapter is mounted on the lens system to capture an image of a microscope, the angle of view of the lens of the digital camera is wide angle. Because it is for shooting,
There is about 60 °. However, since the view angle of the eyepiece of the microscope is as small as about 30 °, even if the digital camera is mounted as it is, the field of view becomes a vignetting image.

The present invention is to solve the above-mentioned problems, and its lens design is easy, and since the parallel light flux plane is formed between the eyepiece lens and the imaging lens, even if the imaging lens is slightly moved. Since it does not affect aberrations so much, it is easy to focus on the CCD image pickup surface, and the entrance pupil of the imaging lens is near the front focal point of the lens and there is a telecentric image formation.
An object of the present invention is to provide an adapter which has a small angle characteristic of a D image pickup element, has no image plane unevenness, and can be attached to a microscope or a telescope to easily capture the image.

[0011]

An adapter is provided with an eyepiece without using a field lens, and the lens is designed so that a parallel light flux from this eyepiece enters a lens on the side of an imaging camera. Conventionally, since the field lens is arranged and the light beam from the objective lens is folded along the optical axis,
The light from the field lens to the relay lens is not parallel. On the other hand, in the present invention, a parallel light beam (that is, infinite image formation) is used from the eyepiece lens, and the lens of the camera forms the parallel light beam on the image pickup surface. At this time,
Since a parallel light flux exists between the eyepiece lens and the camera lens, it is easy to focus the CCD image pickup surface. Further, since the entrance pupil of the imaging lens is telecentric near the front focal point of the lens, the CCD image sensor angle characteristic is small and the image plane unevenness is eliminated.

That is, the present invention is an imaging adapter in which one end is inserted into a lens barrel on the image forming side and an imaging device is attached to the other end, and an eyepiece lens and a lens of the imaging device are housed inside. By utilizing the parallel light flux (infinity imaging) emitted from the eyepiece lens, the entrance pupil of the lens of the image pickup apparatus is close to the front focus position of the lens, and the exit pupil position of the eyepiece lens is almost the same. It is characterized by being arranged so as to match.

The image pickup adapter can be inserted into an eyepiece insertion tube of a microscope or a telescope. Further, the image pickup device can be a camera using a CCD image pickup device or a camera using a CMOS image pickup device. In addition, a reticle can be installed.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION An example of an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a sectional structure of an adapter of an embodiment of the present invention, which is a CCD camera (CCD mount).
The state in which the adapter of this embodiment is attached is shown in FIG. Figure 2
It is a figure explaining the optical system of FIG. 1, and is a figure explaining a lens arrangement. FIG. 3 is a diagram showing an example of a state in which the adapter is attached to the CCD.

That is, the adapter of the present invention is an imaging adapter in which one end is inserted into the lens barrel of the microscope on the eyepiece side, and the mount of the CCD camera is attached to the other end.
The eyepiece lens and the lens of the CCD camera are housed inside, and the parallel light flux emitted from the eyepiece lens is used so that the front focus of the imaging lens is close and the exit pupil of the eyepiece lens and the position of the eyepiece lens are substantially aligned. The entrance pupil is located at.

Here, the eyepiece lens section is composed of a plano-convex lens G1 on the objective lens side and a combination lens of a biconvex lens G2 and a concave lens G3 on the CCD image pickup section side. Also, C
The CD camera lens is a plano-concave lens G4 and a biconvex lens G5
It consists of a combination lens. In front of the CCD image pickup surface is a low-pass filter for cutting high spatial frequency light from the lens system, and a reticle is installed on the focal plane in front of the plano-convex lens of the eyepiece.

Here, the specifications of this adapter will be specifically described. The maximum outer diameter is 33 mm, and the adapter is to be inserted into a standard microscope lens barrel. The length is 71.
It was set to 5 mm. Regarding the optical characteristics of the lens, in terms of the eyepiece system, the plano-convex lens G1 of the eyepiece is provided at a position 9 mm from the image plane of the objective lens, and the eyepiece focal length is 25 mm. Regarding the camera lens system, the lens focal length of the image pickup unit is 1
It is 2.5 mm. The CCD connection is a CS mount.

Here, the positions of the exit pupil of the eyepiece lens and the entrance pupil of the CCD camera lens are set to be substantially the same. Here, the exit pupil refers to an image of the aperture of the objective lens with respect to the optical system thereafter, and the exit pupil refers to a conjugate image of the aperture. In the case of a microscope image pickup device, the exit pupil position of the microscope eyepiece is usually about 10-15 mm from the lens barrel of the eyepiece because it is easy to observe with human eyes.
The reticle is placed on the focal plane of the eyepiece lens, and in this embodiment, the position of the entrance pupil of the CCD camera lens is close to its front focus and further aligned with the exit pupil of the eyepiece lens so that the reticle is parallel between the eyepiece lens and the camera lens. Because of the light, it is possible to easily focus on the CCD image pickup surface, and because of the telecentric image formation, the CCD image pickup element has a small angle characteristic, image surface unevenness is eliminated, and a reticle can be inserted to measure the dimensions. .

Although the embodiment of the present invention has been described using the example of a microscope, the same applies to an adapter which is attached to the lens barrel of a telescope to capture an image. Further, although an example using a CCD camera has been described, a device using a CMOS image pickup device or a camera device using another image pickup device may be used.

[0021]

As described above, according to the present invention, since the field lens is not used, the optical design of the adapter becomes easy. Also, since a general-purpose eyepiece lens can be used, a reticle can be installed, an adapter can be provided at low cost, focusing can be easily performed on the CCD image pickup surface, and furthermore, telecentric imaging is possible. The CCD image pickup element has little angular characteristics, and the unevenness of the image plane is eliminated.

[Brief description of drawings]

FIG. 1 is a view showing a cross section of an adapter according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating an optical system of an adapter according to an embodiment of the present invention.

FIG. 3 is a diagram showing a state in which the adapter of the embodiment of the present invention is attached to a microscope.

FIG. 4 is a diagram illustrating an optical system of a conventional adapter.

[Explanation of symbols]

G1 Plano-convex lens G2 biconvex lens G3 concave lens G4 Plano-concave lens G5 biconvex lens

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H04N 5/225 H04N 5/225 FF term (reference) 2H039 AA01 AB55 AC04 2H044 AA04 AE06 AJ04 AJ06 2H052 AD37 AF14 2H087 KA09 KA15 LA27 MA08 PA03 PA19 PB05 QA01 QA07 QA13 QA21 QA26 QA34 QA42 QA46 RA42 5C022 AA13 AC42 AC54 AC77 AC78

Claims (3)

[Claims] 1. An imaging adapter in which one end is inserted into a lens barrel on the image forming side and an imaging device is attached to the other end, wherein an eyepiece lens and a lens of the imaging device are housed therein, and the eyepiece. Parallel output from the lens (imaging at infinity)
An imaging adapter, which is arranged such that an entrance pupil of a lens of the imaging device is close to a front focal position of the lens and a position of an exit pupil of the eyepiece lens is substantially aligned by using a light flux. 2. The imaging adapter according to claim 1, wherein the imaging adapter is inserted into an eyepiece insertion barrel of a microscope. 3. The imaging adapter according to claim 2, wherein the imaging device is a CCD imaging device camera.