JPH0384526A - Finder optical system with photometric system - Google Patents

Abstract

PURPOSE:To secure a size for stably holding a photodetection sensor and to improve the incorporation and assembly of the fiber optical system in a finder structure body by fitting and fixing a support substrate for the photodetection sensor to the finder structure body at a lateral attitude almost parallel to the front-rear direction of th finder system. CONSTITUTION:The substrate 14 where the photodetection sensor 13 is supported is fitted and supported on the finder structure body 20 at the lateral attitude almost parallel to the front-rear direction of the finder by being positioned by engaging a dowel 20a for positioning which is projected from part of the finder structure body 20 with a dowel engagement hole 1a on the side of the substrate 14. The size of the photodetection sensor holding substrate 14 is larger in the finder front-rear direction than in the finder cross section direction, and the degree of freedom of the design is large. Consequently, the substrate 14 can be made large to held the photodetection sensor 13 and the incorporation and assembly in the finder structure body 20 are improved.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a finder optical system having a photometry system suitable for a photographing device such as a still video camera.

(Prior Art) Conventionally, photometry in compact cameras has been carried out through a photometry window that is placed separately from the photographic lens and finder system. However, in recent years, compact cameras have become equipped with zoom lenses, so with conventional configurations, there are problems such as increased parallax in the photometry system on the telephoto lens side, and the photometry range relative to the shooting screen changes greatly when zooming. It's coming.

In particular, cameras with small photographic screen dimensions, such as still video cameras, can be constructed with a small photographic lens, making zooming relatively easy. Therefore, in such a still video camera, the above-mentioned problem 6<111 arises.

Therefore, we have developed a so-called external finder system that performs viewfinder observation at a position different from that of the photographing system, and the finder system is connected to the objective concave lens l, A convex objective lens 2, a first field lens 3. a primary focusing surface 4, a half mirror 5, a total reflection mirror 6 disposed on the reflection side of the half mirror 5, a secondary imaging lens 7, a second field lens 8. It is composed of optical members such as a secondary focusing surface 9 and an eyepiece lens 10, and a condensing lens 11 for photometry is provided on the transmission side of the half mirror 5.
By arranging the colored glass 12 and the light receiving (photometering) sensor 13 to form a photometry system, it is possible to eliminate variations in the photometry system and to optimally set the photometry range for the photographic screen.

A concave objective lens 1 and a convex objective lens 2 constitute an objective lens system capable of variable magnification. The convex objective lens 2 moves from the image side to the object side to increase the magnification, and the concave objective lens 1 corrects the movement of the image plane accompanying the change in magnification. The first field lens 3 has the role of focusing the light beam of the objective lens system near the entrance pupil of the secondary imaging lens 7. The secondary imaging lens 7 is 1
It has a function of re-imaging the primary image of the objective lens system formed on the secondary focus surface 4 on the secondary focus surface 9. The second field lens 8 has the role of focusing the light beam of the secondary imaging system near the position of the eye.

The finder system constituted by the optical member 1-10 of this example is a real image finder system using a secondary imaging method that is employed when the camera has a long depth, and is a zoom finder in which the objective system is zoomed.

The half □ color 5 has the role of folding the finder optical path in order to shorten the depth dimension of the camera, and at the same time has the role of transmitting a portion of the light amount to the photometry system. A photometric system is composed of a condensing lens 11 for photometry, a colored glass 12, and a light receiving sensor 13 arranged behind the half mirror 5.

A condensing lens 11 for photometry forms an image of the primary focus plane 4 in the vicinity of a photometry sensor 12, and measures the light of a specific portion of the finder screen. It should be noted that since the photometry system is located behind the first field lens 3, photometry can be performed on the periphery without vignetting.

The optical members 11-13 of the photometry system are arranged in order on the optical axis of the transmitted light of the half mirror 5 toward the rear of the half mirror, and the half mirror 5, the condensing lens 11 for photometry, and the colored glass 12 are arranged as shown in FIG. 4(b). The light receiving sensor 13 is fixedly positioned on the finder structure (I! body) 20 as shown in FIG. It is positioned by fitting into the dowel engagement hole 14a provided on the substrate 14 side, and is fixedly attached to the finder structure 20.

(Problems to be Solved by the Invention) However, the optical system with the above layout has the following problems.

That is, since the photometric system has a configuration in which the constituent optical members 11 to 13 are arranged in order toward the rear of the half mirror on the optical path of the transmitted light of the half mirror 5, which is the front and back direction of the finder,
The substrate 14 on which the light receiving sensor 13 is attached and held is installed and fixed in the finder structure 20 in a vertical position, which is the transverse cross-sectional direction of the finder structure 20, as shown in FIG. 4(b). In this case, the cross section of the finder structure is originally small in terms of area, and the area that the substrate 14 can occupy within that cross section is further limited, and the designable dimensions of the substrate 14 in both the vertical and horizontal directions are small. Therefore, there are problems such as difficulty in securing a sufficient size for the substrate 14 to stably hold the light receiving sensor 13, and difficulty in assembling and assembling it into the finder structure 20. This problem becomes more serious as the finder becomes smaller.

The present invention aims to solve such problems.

(Means for Solving the Problems) The gist of the present invention is a finder optical system having a photometric system characterized by the following configuration.

(1) A half mirror that splits the optical path is arranged between the field lens of the external finder system that performs finder observation with a finder system installed independently of the 11 shadow system and the secondary imaging lens, and the half mirror In a finder optical system that includes a photometric system including a condensing lens for photometry and a light-receiving sensor on the transmission side, the optical path of the transmitted light of the half mirror, which is in the front-rear direction of the finder, is arranged in the photometric system in a direction approximately perpendicular to the optical path. A finder optical system having a photometric system, characterized in that the light whose optical path has been changed by the reflective surface member is reflected by a light receiving sensor supported by a substrate mounted and fixed to the finder structure in parallel.

(2) The photometric condensing lens and reflective surface member of the photometric system are constructed of an integrally molded optical element having a refractive surface portion that functions as a condensing lens and a reflective surface portion that functions as a single reflective surface member. A finder optical system having the photometric system according to (1) above.

(3) A finder optical system having a photometric system according to item 2 (1), characterized in that a colored glass adhesively fixed to the optical element is interposed between the optical element and the light receiving sensor.

(4) One or both of the optical element and the colored glass, which are adhesively fixed to each other, are provided with mutual positioning means. A finder optical system having the photometric system according to (3) above.

(5) The optical element and the light-receiving sensor substrate are provided with a dowel and a dowel engaging portion that are positioned relative to each other. A finder optical system comprising the photometric system according to any one of (2) to (4) above.

(6) A finder optical system having a photometric system, characterized in that the optical element and the light receiving sensor are provided with a mutually positioning fitting part and fitted together.

(Function) That is, as described in item (1), the photometric system has an optical member arrangement structure that allows the support substrate of the light receiving sensor to be mounted and fixed on the finder structure in a horizontal position approximately parallel to the front and back direction of the finder system. By doing so, there is a greater degree of freedom in designing the size of the light receiving sensor support substrate to be larger in the front-rear direction of the finder than in the transverse direction of the finder.

Therefore, it is possible to increase the size of the substrate, that is, to ensure a sufficient size to stably hold the light receiving sensor, and it is also easy to incorporate and assemble into the finder structure.

The structures of items (2) to (6) make it easy to align and position the optical members constituting the spotlight system, and have the advantage of being easy to design, easy to assemble, and highly accurate.

<Example> FIGS. 1(a) and 1(b) show an example. Components and portions that are the same as those in the examples shown in FIGS. 4(a) and 4(b) are given the same reference numerals and will not be described again.

In this embodiment, the photometric imaging lens and the reflective surface member of the photometric system are integrally molded (1) having a refractive surface portion 11a that functions as an imaging lens and a reflective surface portion 11b that functions as a reflective surface member.
The optical element 11A (molded) is M4.

The reflective surface portion 11b of the optical element 11A allows the optical element 11 to pass through the half mirror 5 from the refractive surface portion 11a.
The light incident on A is reflected downward. That is, the half mirror transmission optical path or reflective surface portion 11 in the front and back direction of the finder.
b, the half-mirror transmission optical path is changed downward in a direction substantially perpendicular to the optical path. In this embodiment, the light emitting surface of the optical element 11A is provided with colored glass 12, which is positioned and bonded in advance.The light reflected downward at the reflective surface portion 11b is colored from the light emitting surface of the optical element 11A. The light passes through the glass 12 and enters the light receiving sensor 13 facing the colored glass 12.

The half mirror 5 is held by the finder structure 2o, and the optical element 11A to which the zero color glass 12 is bonded is also held by the finder structure.

The substrate 14 supporting the light receiving sensor 13 is placed in a horizontal position substantially parallel to the front-rear direction of the finder, with the positioning dowel 20a protruding from a part of the finder structure 2o and the substrate 14 side facing the finder structure 20. Dowel engagement hole 14a
It is positioned by engaging the bamboo and supports the installation.

Therefore, the size of the light receiving sensor holding substrate 14 is as follows compared to the cross-sectional direction of the finder MA in the fourth sections (a) and (b).
Since the finder is larger in the front and back direction and has a greater degree of freedom in design, the substrate 14 can be made large enough to hold the light receiving sensor 13, and it is easy to incorporate and assemble into the finder structure 2o.

When the colored glass 12 interposed between the optical element 11A and the light receiving sensor 13 is adhesively fixed to the optical element 11A,
A positioning means for mutually positioning one or both of the optical member 11A and the colored glass 12, such as a positioning protrusion,
It is advisable to provide a hole/convergence part. Fig. 2 shows the optical element 11A.
This figure shows an example in which the hook members 11A-12 are aligned with each other by providing a recess 11c into which the colored glass 12 is fitted on the light emitting surface. However, the colored glasses 12 may be independently attached to and supported by the finder structure 20.

Also, optical elements! 1A or the colored glass 12 integrally bonded to the optical element 11A, and the light receiving sensor 13 or the substrate 14 holding the sensor, a mutual positioning means, such as a positioning protrusion, hole, etc.
It is preferable to provide a liquid fitting part. In FIG. 3, the colored glass 12 is positioned and bonded to the optical element 11A by the liquid fitting recessed hole part 11c, and a dowel lid is provided on a part of this optical element 11A for positioning. An example is shown in which the optical element 11A and the light receiving sensor 13 are aligned by fitting the dowel lid and the dowel fitting hole 14b provided on the light receiving sensor substrate 14 side and bonding or welding the dowel lid.

(Effects of the Invention) As described above, according to the present invention, it is possible to secure a sufficient size for stably holding the light receiving sensor for the light receiving sensor holding board of the photometry system, and it is possible to incorporate the light receiving sensor into the finder structure.・Easy to assemble.Also, it is easier to align and position the optical components that make up the photometric system, and it is easier to design and assemble. Often distant relatives.

[Brief explanation of drawings]

FIG. 1(a) is a schematic diagram of an optical system of one embodiment, and FIG. 1(b) is a schematic diagram of an optical system of one embodiment.
is an enlarged vertical sectional view of the photometric system, FIGS. 2 and 3 are schematic diagrams of mutual positioning means for the optical members constituting the photometric system, and FIG. 4(a) is a schematic diagram of a conventional optical system. Figure, same figure (b
) is an enlarged vertical cross-sectional view of the photometric system. 1 to 10 are finder optical systems, 11 to 13 are photometric optical systems, 5 is a half mirror, 11A is a molded optical element, 13 is a light receiving (g4 light) sensor, and 14 is its support substrate.

Claims (6)

[Claims] (1) The finder image formed on the first object plane by an objective lens provided independently of the photographing system is re-imaged on the second object plane by a secondary imaging lens via a field lens, and
A half mirror that divides the optical path is arranged between the field lens and the secondary imaging lens of an external finder system in which an object image is observed through the eyepiece, and the light beam reflected by the half mirror is transmitted to the eyepiece. A finder optical system that guides light to a lens side and guides a luminous flux that has passed through the half mirror to a photometry system including a condenser lens and a light receiving sensor, wherein a part of the photometry system includes a light beam from the half mirror. A reflecting member is arranged to reflect the transmitted light beam in a direction substantially perpendicular to the finder optical axis, and the light receiving sensor is supported on a substrate attached and fixed to the finder structure substantially parallel to the finder optical axis, and the light receiving sensor is supported on a substrate fixed to the finder structure, and A finder optical system having a photometric system, characterized in that a light beam is incident on the light receiving sensor. (2) The photometric system according to claim 1, wherein the condensing lens and the reflecting member are formed of an integrally formed optical element having a refractive surface portion acting as a condensing lens and a reflective surface portion. Finder optical system with. (3) A finder optical system having a photometric system according to claim 2, characterized in that a colored glass adhesively fixed to the optical element is interposed between the optical element and the light receiving sensor. (4) A finder optical system having a photometric system according to claim 3, characterized in that one or both of the optical element and the colored glass, which are adhesively fixed to each other, are provided with mutual positioning means. (5) The photometric system according to any one of claims 2 to 4, characterized in that the optical element and the light receiving sensor board are provided with a dowel and a dowel engaging portion for mutually positioning the optical element and the light receiving sensor board. Finder optical system. (6) Claim 5 characterized in that the optical element and the light receiving sensor are provided with a fitting portion for mutual positioning and are fitted together.
A finder optical system having the photometric system described above.