JP2006276484A - Device for visibility adjustment and finder device having the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To adjust visibility to the one according to user's eyesight, while having simple structure in which miniaturization, weight reduction and convenience of handling are contrived. <P>SOLUTION: This device for visibility adjustment is constituted by arranging a main optical system consisting of a both convex shaped lens L and a both convex shaped prism P and a compound lens element 2, in the order starting from the object side. The cemented lens element 2 is constituted, by filling a first fluent substance 21 and a second fluent substance 22 with mutually different refractive indexes in a container 24 along an X axis and joining each other, has structure that the shape of a jointing surface 23 between the first fluent substance 21 and the second fluent substance 22 changes according to change of voltage to be impressed from a voltage impression circuit 50 and whose refracting power changes by the change in the shape of the joint surface 23. Furthermore, predetermined conditions regarding the structure of the cemented lens element 2 are satisfied. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a diopter adjusting device disposed on the pupil side of a main optical system in a spectacle device such as a camera finder device, and a finder device including the diopter adjusting device.

  2. Description of the Related Art Conventionally, for example, a camera finder device is known in which an eyepiece is exchanged in accordance with a photographer's visual acuity (for example, see Patent Document 1 below). Also, there is known an eyepiece that is fitted with an attachment lens for diopter adjustment to obtain an appropriate diopter.

  There is also known a method for adjusting diopter by moving a part of a lens constituting the finder device along the optical axis (see, for example, Patent Document 2 below).

JP-A-9-274148 JP-A-8-110559

  However, the finder apparatus described in the above-mentioned Patent Document 1 or the above-described apparatus in which an attachment lens is attached to an eyepiece does not perform an operation of attaching or detaching the eyepiece itself or a diopter adjustment attachment lens every time a photographer is different. And I can't stand the trouble.

  In addition, the diopter adjusting device described in Patent Document 2 requires a physical mechanism for moving some lenses of the main optical system, which complicates the structure of the finder device and increases its size. Therefore, it cannot be made a compact camera.

  In recent years, digital cameras that have become widespread have been desired to be smaller, lighter, and easier to handle. However, the use of a conventional finder device cannot meet such demands.

  The problem occurring in such a camera finder apparatus is a common problem to be solved in other spectacle apparatuses such as binoculars and a microscope.

  The present invention has been made in view of the above-described circumstances, and is a simple mechanism that achieves miniaturization, weight reduction, and convenience of handling, and can be used to adjust diopter according to the user of the eyeglass device. It is an object of the present invention to provide a degree adjusting device and a finder device including the same.

The diopter adjustment device of the present invention is a diopter adjustment device arranged on the pupil side of the main optical system of the eyeglass device,
A cemented lens element having a variable refractive power, the cemented lens element joining a first fluid material and a second fluid material having different refractive indexes along the optical axis and to each other; The container has a structure in which the shape of the joint surface between the first fluid substance and the second fluid substance changes according to a change in applied voltage while being filled in the container,
The following conditional expression (1) is satisfied.

0.1 <| N _d1 −N _d2 | <0.5 (1)
However,
N _d1 : Refractive index at the d-line of the first fluid substance N _d2 : Refractive index at the d-line of the second fluid substance

  Further, it is preferable that both the light incident surface and the light emitting surface of the cemented lens element are formed by a flat surface.

  In the diopter adjustment device, it is preferable that the following conditional expression (2) is satisfied.

0.01 <L / | R | <0.1 (2)
However,
R: radius of curvature at the time of maximum deformation of the cemented lens element L: thickness of the cemented lens element

  Further, it is preferable that the diopter adjusting device is detachable from a frame (mechanical frame) that houses the main optical system.

  In addition, a finder device according to the present invention includes any one of the above diopter adjustment devices arranged on the pupil side of the main optical system, and further includes a voltage application circuit that outputs a voltage to be applied to the cemented lens element. It is characterized by this.

  In the present specification, “diopter” means diopter described on page 524 of “Physical and Chemical Dictionary (4th edition): Iwanami Shoten”.

  According to the diopter adjusting device of the present invention, the diopter of the eyeglass device can be adjusted well by adjusting the refractive power of the cemented lens element.

  In addition, since the cemented lens element can easily and easily change the refractive power by changing the applied voltage, it is possible to obtain an eyeglass device with a simple structure that is compact, lightweight, and easy to handle. be able to.

  In particular, it is arranged on the pupil side of the main optical system, and is provided with a voltage application circuit that outputs a voltage to be applied to the cemented lens element, thereby simplifying the size, weight, and convenience of handling. A finder device having a structure can be obtained.

  Hereinafter, embodiments of a diopter adjusting device and a finder device including the same will be described with reference to the drawings.

FIG. 1 is a configuration diagram of a viewfinder device according to a first embodiment of the present invention.
This finder device is a finder device of a camera. As shown in FIG. 1, a main optical system including a biconvex lens L and a biconvex prism P, and a cemented lens element 2 are arranged in order from the object side. It is arranged. In FIG. 1, X indicates an optical axis. The cemented lens element 2 constitutes a diopter adjusting device.

  The cemented lens element 2 has a first fluid material 21 and a second fluid material 22 having different refractive indexes arranged along the optical axis X and is joined to each other and filled in a container 24. The shape of the joint surface 23 between the first fluid substance 21 and the second fluid substance 22 changes according to the change in the voltage applied from the voltage application circuit 50. The refractive power changes as the shape of the surface 23 changes. The light incident end face and the light exit end face of the cemented lens element 2 are both flat.

  The cemented lens element 2 is known as, for example, a Fluid Focus lens manufactured by Philips, the Netherlands, and has a conductive container having different refractive indexes in a cylindrical container whose both end faces in the optical axis X direction are transparent. Water-soluble liquid (for example, the first fluid substance 21) and a non-conductive oily liquid (for example, the second fluid substance 22) are encapsulated, and the water-soluble liquid is changed according to switching of the voltage applied to the container. The refractive power can be changed by changing the shape of the boundary surface between the functional liquid and the oily liquid by the surface tension. That is, when giving a predetermined refractive power, for example, the cemented surface 23 of the cemented lens element 2 has a curved surface shape as shown in FIG. In the case where no refractive power is given, for example, the cemented surface 23 of the cemented lens element 2 has a planar shape as shown in FIG. 2B (a plane section is shown). The

  The voltage value applied from the voltage application circuit 50 to the cemented lens element 2 is set by setting a setting switch (not shown). The setting switch may be set to ON / OFF binary switching or multi-level switching of three or more values.

  The cemented lens element 2 satisfies the following conditional expressions (1) and (2).

0.1 <| N _d1 −N _d2 | <0.5 (1)
0.01 <L / | R | <0.1 (2)
However,
N _d1 : Refractive index at the d-line of the first fluid substance N _d2 : Refractive index at the d-line of the second fluid substance R: Curvature radius at the maximum deformation of the cemented surface of the cemented lens element L: Joint lens element Thickness

  Hereinafter, the technical significance of the conditional expressions (1) and (2) will be described.

That is, the conditional expression (1) is a conditional expression that defines an absolute value N _d1 -N _d2 of a difference in refractive index between two fluid substances bonded in the cemented lens element 2. In the conditional expression (1), when the absolute value of N _d1 −N _d2 is less than the lower limit, the change in diopter with respect to the change in the radius of curvature R of the joint surface 23 becomes small, and efficient diopter adjustment can be performed. Can not. On the other hand, when the value exceeds the upper limit, problems such as a decrease in the light transmittance of the high refractive material (yellowishness) generally occur, making it difficult to produce a high-performance product.

  Conditional expression (2) defines the thickness of the cemented lens element 2 with respect to the radius of curvature R at the time of maximum deformation of the cemented surface 23 of the cemented lens element 2. The thickness of the cemented lens element 2 is too small, which is not preferable in manufacturing. If the upper limit is exceeded, the thickness of the cemented lens element 2 increases, and as a result, the distance (eye relief) from the final exit surface to the eye point 1 is shortened, resulting in poor usability.

<Example 1>
Specific data regarding the finder apparatus according to the first embodiment will be described below. In order to facilitate understanding of the distance relationship in the optical axis direction of the optical system of the apparatus shown in FIG. 1, FIG.

Table 1 below shows the radius of curvature R (mm) of each lens surface, the axial top surface distance (center thickness of each lens and the air space between each lens) D (mm) for the finder apparatus of Example 1. The refractive index N _d and Abbe number ν _d at the d-line of each lens are shown. In Table 1, the numbers corresponding to the respective symbols are sequentially increased from the object side. In Table 1, surfaces 5, 6, and 7 represent the light incident surface, the cemented surface, and the light emitting surface of the cemented lens element 2, respectively.

  In Table 1 below, the surface marked with * to the left of the surface number represents an aspheric surface, and each aspheric surface is represented by the following aspheric expression.

Table 2 below shows the values of the eccentricity K and the fourth, sixth, eighth, and tenth aspheric coefficients A ₄ , A ₆ , A ₈ , and A _{10 related to} the aspheric surface.

  Table 3 below shows the values of the conditional expressions (1) and (2) in the finder apparatus of Example 1.

  Further, in Table 1, the radius of curvature of the cemented surface 23 of the cemented lens element 2 is 94.31, which results in an adjustment amount of +3 diopters.

  When the radius of curvature of the cemented surface 23 of the cemented lens element 2 is −94.31, the adjustment amount is −3 diopters. At this time, the thickness along the optical axis X is 1.01 for the lens made of the first fluid substance 21 and 0.99 for the lens made of the second fluid substance 22.

  Further, when the diopter is not adjusted, the radius of curvature of the joint surface 23 is ∞ (the state shown in FIGS. 1 and 2B).

  Further, as apparent from Table 3 below, the finder device (diopter adjustment device) of Example 1 satisfies the conditional expressions (1) and (2).

  The main optical system constituting the optical system of the finder apparatus together with the cemented lens element 2 is not limited to that of the first embodiment. For example, the number of elements other than the cemented lens element may be one, or three or more. Also good.

  In addition, the diopter adjustment device may have a mounting portion that can be attached to, for example, an end surface portion on the pupil side of the frame body 10 that houses the main optical system of the eyeglass device. You may comprise so that the whole diopter adjustment apparatus may be screwed with respect to this frame 10. FIG. Of course, the diopter adjusting device may be incorporated into the eyeglass device from the beginning.

1 is a configuration diagram of a viewfinder device according to a first embodiment of the present invention. The figure for demonstrating the change state of the joint surface according to a voltage application in the cemented lens element shown by FIG. FIG. 1 is a development configuration diagram in the optical axis direction of the optical system of the finder apparatus shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Eye point 2 Joint lens element 10 Frame 21 1st fluid substance 22 2nd fluid substance 23 Joint surface 24 Container 50 Voltage application circuit L Lens P Prism

Claims (5)

A diopter adjustment device arranged on the pupil side of the main optical system of the spectacle device,
A cemented lens element having a variable refractive power, the cemented lens element joining a first fluid material and a second fluid material having different refractive indexes along the optical axis and to each other; The container has a structure in which the shape of the joint surface between the first fluid substance and the second fluid substance changes according to a change in applied voltage while being filled in the container,
A diopter adjustment device that satisfies the following conditional expression (1):
0.1 <| N _d1 −N _d2 | <0.5 (1)
However,
N _d1 : Refractive index at the d-line of the first fluid substance N _d2 : Refractive index at the d-line of the second fluid substance 2. The diopter adjusting device according to claim 1, wherein both the light incident surface and the light emitting surface of the cemented lens element are formed as flat surfaces. The diopter adjustment device according to claim 1, wherein the following conditional expression (2) is satisfied.
0.01 <L / | R | <0.1 (2)
However,
R: radius of curvature at the time of maximum deformation of the cemented lens element L: thickness of the cemented lens element The diopter adjustment apparatus according to claim 1, wherein the diopter adjustment apparatus is insertable into and removable from a frame body that houses the main optical system. A diopter adjustment device according to any one of claims 1 to 4 is provided on the pupil side of the main optical system, and further includes a voltage application circuit that outputs a voltage to be applied to the cemented lens element. A finder device characterized by that.

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