JPS61110117A - Diopter adjusting device using liquid crystal - Google Patents

Abstract

PURPOSE:To obtain a diopter adjusting device which facilitates a diopter adjust ment and eliminates restriction of its fitting position and is reducible in size and weight by using a liquid crystal lens for part of an occular lens and varying the focal length of the liquid crystal lens. CONSTITUTION:The occular lens of an occular part is constituted by using the liquid crystal lens 4. This liquid crystal lens 4 have liquid crystals 9a and 9b charged between both surfaces of a transparent plate 6 and convex lenses 8a and 8b. Values of voltages or magnetic fields applied to the liquid crystals 9a and 9b or their frequencies are varied to vary the refractive index on the basis of variation of the orientation of molecules of the liquid crystals 9a and 9b and thus the focal length of the liquid crystal lens 4 is varied to adjust the diopter.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a diopter adjustment device using a liquid crystal suitable for use in an eyepiece of an optical instrument.

[Technical background of the invention and its problems] In general, in optical instruments such as endoscopes, microscopes, cameras, binoculars, and telescopes that are observed with the naked eye through the eyepiece, even if the diopter of the observer is different, The eyepiece is equipped with a diopter and adjustment device so that a clear image can be obtained. For example, Japanese Utility Model Application Publication No. 57-164038 discloses a diopter adjustment means for an endoscope.

The diopter adjustment devices in these optical instruments are generally designed to allow a person of any diopter to adjust the diopter over a fairly wide range so that the user can see clearly even without glasses. Therefore, when used by people with significantly different diopters, it is necessary to perform adjustment work while looking through the eyepiece each time the user changes. In normal use, the number of users is limited, but each time a person with a different diopter views the lens, it must be readjusted, which is a cumbersome task. In addition, the part for adjusting the diopter has the disadvantage that the lens frame etc. must be moved back and forth, and in order to make the back and forth movement smooth, the diopter adjustment mechanism becomes complicated, and is bulky and heavy. increase Therefore, it becomes difficult to operate with binoculars, endoscopes, etc., which is a drawback. Furthermore, there is also the inconvenience that the diopter adjustment mechanism can only be attached to certain locations.

[Object of the Invention] The present invention has been made in view of the above-mentioned points, and provides a diopter W4I device using a liquid crystal that allows easy diopter adjustment, is not limited to a specific mounting location, and can be made smaller and lighter. The purpose is to

[Summary of the Invention] The present invention provides at least a part of an eyepiece of an eyepiece of an optical device using a liquid crystal lens, and a voltage or a magnetic field applied to the liquid crystal lens, or a value or a frequency thereof, can be varied. A means for adjusting the diopter by varying the focal length of the liquid crystal lens is constituted.

[Embodiments of the invention] Hereinafter, the present invention will be specifically explained with reference to the drawings.

1 and 2 relate to a first embodiment of the present invention, in which FIG. 1 shows the first embodiment provided in the eyepiece part of an endoscope, and
The figure shows the electrical configuration of the first embodiment.

The first embodiment is as shown in FIG.
It is set in.

The endoscope 1 has an objective lens system housed at the distal end of an insertion section (not shown), and connects an object such as an affected area illuminated with illumination light emitted from the distal end of a light guide to the front end surface of an image guide 3. The image guide 3 allows the image to be transmitted to the rear end surface 3a on the eyepiece section 2 side.

The image transmitted to this rear end surface 3a passes through a liquid crystal lens 4 as an eyepiece fixed to the inner wall of the eyepiece section behind it, and the eye can be brought close to the cover glass 5 behind the liquid crystal lens 4. This allows for magnified observation.

The liquid crystal lens 4 forming the eyepiece has spacers 7a at the corners of both sides of the transparent plate 6, as shown in an enlarged view in FIG.
Liquid crystals 9a and 9b are sealed in parallel plate-like cells formed by convex lenses 8a and 8b, which are arranged opposite to each surface of the transparent plate 6 with a frame 10 interposed therebetween. is fixed.

Transparent electrodes 11a such as SiO2 are provided on both sides of the transparent plate 6,
11b are provided, and these electrodes 11a.

Transparent electrodes 12a, 12b are also provided on the inner surfaces of convex lenses 8a, 8b facing 11b, and these ff1i11
a, 12a: The liquid crystals 9a, 9 are controlled by varying the applied voltage to control the orientation of the liquid crystal molecules of the liquid crystals 9a, 9b.
Means is provided for electrically varying the focal length of the liquid crystal lens 4 by changing the refractive index of b. Outer transparent electrode 12a.

12b are electrically connected to each other and grounded, and the inner transparent electrode 1
18.11b are also electrically connected to each other and connected to one contact 13A. This contact point 13A is a movable contact point provided with a short width (in the direction perpendicular to the plane of the paper in FIG. 1) on the inner circumference of the operation ring 14 for adjusting the diopter, which is fitted and housed in a recess or groove formed on the outer circumference of the eyepiece section 13. The movable contact 14B conducts with the contact 14B, and the movable contact 14B has short width contacts 13C+ and 13C formed between 111 in the rotational direction depending on its rotational (rotational) position.
2, . . . , 13Cs.

Each of the above-mentioned contacts 13C+, .

..., represented by Rs) to the AC output terminal of the DC/AC converter 16. This DC/A
C converter 16 is connected to battery 18 via switch 17 .

The battery 18 is a low voltage DC voltage such as a mercury battery.
A frequency suitable for the liquid crystals 9a and 9b used by the AC converter 16, for example, 1 KHz, for example.
AC1 below 0V! Pressure. As shown in FIG. 1, this battery 18 is housed in a recess formed in the outer peripheral wall of the eyepiece 2 so that it can be replaced at 119. Also, DC/AC converter 16° switch 17. The integrated resistive element 15 and the like are also provided in this peripheral area.

Rotate the operation ring 14 for adjusting the diopter and contact 14A.
Contact point 1. ¥Ci (i-1,2゜...
5), the AC voltage applied to the liquid crystals 9a, 9b is variably set, and the applied voltage changes the AC voltage applied to the liquid crystals 9a, 9b.
The refractive index is varied based on changes in the orientation of liquid crystal molecules, and the focal length of the liquid crystal lens 4 is varied to adjust the diopter.

By the way, in the liquid crystal lens 4, each of the liquid crystals 9a and 9b has the same characteristics, and when no voltage is applied, the alignment state of each liquid crystal molecule, that is, the optical axis direction is the second.
As shown by the symbols A and B in the figure, they are aligned so that they are orthogonal to each other, and these optical axis directions A and B are perpendicular to the optical axis of the liquid crystal lens 4, and each has a focal length that does not require a polarizing plate. It constitutes a variable lens.

That is, the incident light can be decomposed into two mutually orthogonal polarized components, and in FIG. 2, it is considered to be decomposed into the orientation direction A of the liquid crystal molecules of the liquid crystal 9a and the orientation direction 8 of the liquid crystal molecules of the liquid crystal 9b. First, when a polarized component parallel to the alignment direction of A, which is one component of the incident light, enters the liquid crystal 9a, it becomes an extraordinary ray with respect to this light component wave liquid crystal 9a. Therefore, when a voltage is applied to the liquid crystal 9a in this state, the liquid crystal molecules gradually change their direction in a direction perpendicular to the electrodes 11a and 12a according to the voltage, so that the apparent refractive index of the liquid crystal 9a for the extraordinary light component is abnormal. It changes continuously from the value for light to the value for ordinary light, and is affected by the effect of variable focal length. Since this extraordinary light component for the liquid crystal 9a becomes an ordinary light component for the liquid crystal 9b, the apparent refractive index does not change and is not affected by the effect of changing the focal length. Therefore, continue straight ahead. On the other hand, the component corresponding to ordinary light with respect to the other incident light component, the liquid crystal 9a, does not change in the apparent refractive index in the liquid crystal 9a and is not affected by the focal length variable effect, but in the liquid crystal 9b, the component corresponds to the ordinary light. As a result, the apparent refractive index changes (in the liquid crystal 9b) in the same way as when extraordinary light enters the liquid crystal 9a, resulting in the effect of varying the focal length. Since the same voltage is applied to the liquid crystals 9a and 9b, they have the same focal length variable effect.

Therefore, by stacking the two liquid crystals 9a and 9b so that their optical axes are perpendicular to each other, they can operate as a variable focal length lens for polarized light in any direction, without using a polarizing plate. A lens is constructed whose focal length can be varied regardless of the polarization direction of incident light.

According to the first embodiment configured in this way, a person using the endoscope 1 brings his or her eyes close to the eyepiece 2 and switches the switch 1.
7, turn the operating ring 14, and set the appropriate contact 1.
By selecting 3C1 to 13C5, it is possible to set a diopter state that facilitates clear observation.

According to this first embodiment, there is no need for a means for mechanically moving the liquid crystal lens 4, so the structure can be simplified.
Cost can be reduced. Also, it can be made into a small and light fort. It also has the advantage that the eye point does not shift even when the diopter is adjusted.

3 and 4 show a second embodiment of the invention.

In this second embodiment, a slide resistor (receptacle) 21 is provided on the outer periphery of the eyepiece portion 2, and a knob 21 of this slide resistor 21 is provided.
By moving A in the direction shown by arrow C, the AC voltage applied to the liquid crystal lens 4 can be continuously varied.

By the way, the ACN pressure source applied to the liquid crystal lens 4 is a commercial ACIf source in the light source device 22 and an AC/AC converter 23.
This AC voltage is converted into an AClf pressure of an appropriate frequency by
The voltage is applied to the liquid crystal lens 4 via the slide resistor 21 by connecting the connector 24A provided at the end of the eyepiece 4 to the connector receiver 24B provided at the outer periphery of the eyepiece.

Application of AC voltage to the liquid crystal lens 4 is performed by a light source device 22.
It is designed to be activated when the power switch is turned on.

In this embodiment, since the focal length of the liquid crystal lens 4 can be continuously varied, the amount of diopter adjustment can be continuously performed.

FIG. 5 shows a third embodiment of the invention. This third embodiment is the same as the second embodiment except that temperature compensation means is provided.

That is, the liquid crystal lens 5 is provided with temperature measuring means such as a thermistor 31, and the output of this temperature measuring means is connected to the temperature correction circuit 32 in the light source device 22 through the same cable as in the second embodiment. This is so that it is applied to the input terminal. The temperature compensation circuit 32 uses the voltage value set by the slide resistor 21 based on the input temperature signal to keep the focal length (diopter correction value) constant even when there is a vA degree change. , outputs a control signal to the AC/AC converter 23 to variably control the output voltage of the AC/AC converter 23.

The rest of the structure is the same as that of the second embodiment.

According to this third embodiment, if the scale of the slide resistor 21 is set to a certain value suitable for the diopter of the user, there is no need to finely adjust the position of the scale even if the temperature changes. has advantages.

FIG. 6 shows the structure of a selection switch in a fourth embodiment of the present invention, and this structure or a structure similar to this is widely used in key operation means of calculators and the like.

The selection switches 41, 41. ..., 41 is eyepiece section 2
A plurality of them are provided around the outer periphery of the . Each selection switch 41.4
1. . . , 41 are provided with convex leaf springs 43.43° . A contact point 44 is disposed at the center of the contact point 44 so as to be always spaced apart from the leaf spring 43. However, the cover 42
By pressing against the urging force of the leaf spring 43 from the outside, the leaf spring 43 and the contact point 44 can be electrically connected. Circuit means is provided so that when the leaf spring 43 and the contact 44 are turned on, a voltage corresponding to the turned-on state is applied to the liquid crystal lens unless another leaf spring 43 is turned on (as shown in the diagram). ).

In this way, the structure can be sufficiently watertight. Note that instead of the leaf spring 43, an elastic member having a similar function may be used.

The present invention is not limited to the eyepiece of an endoscope, but can be widely applied to optical instruments having means for enabling observation with the naked eye from the eyepiece, such as microscopes, telescopes, binoculars, general cameras, TV cameras, and others. It is something. The applied voltage operating means is not limited to the one provided in the eyepiece 2, but may be operated by a foot switch or the like, which has the advantage that the user can perform other operations. It is also very convenient for people with hand disabilities.

Furthermore, when a photographing device or the like is further attached to the eyepiece to take a photograph or to take an image electrically, the present invention can also be used as a means for changing the imaging position of the objective optical system of the photographing device. This allows you to adjust the focus by remote control even if the subject distance changes.

Note that the focus adjustment of the liquid crystal lens is not limited to control by varying the applied voltage, and may be performed by varying the frequency of the applied voltage. Further, control may be performed using a magnetic field instead of voltage, or may be further controlled using the frequency of the magnetic field.

[Effects of the Invention] As described above, according to the present invention, the eyepiece is composed of a liquid crystal lens using liquid crystal, and an electric focal length variable means is provided to form a diopter adjustment mechanism.
A diopter adjustment mechanism can be provided in a small or small space without requiring mechanical movable means. Moreover, it can be made lighter. Furthermore, the eyepiece can easily be made into a watertight structure.

Furthermore, when observing while wearing a photographing device, it is also possible to adjust the diopter by remote control so that the focus can be adjusted even when the distance to the subject changes.

[Brief explanation of the drawing]

゛Figures 1 and 2 relate to the first embodiment of the present invention;
The figure is a schematic sectional view showing the first embodiment provided in the eyepiece part of the endoscope, FIG. 2 is a configuration diagram showing the electric circuit system of the first embodiment, and FIGS. Regarding the second embodiment, FIG. 3 is a schematic sectional view showing the second embodiment provided in the eyepiece part of the endoscope;
FIG. 4 is a block diagram showing the electric circuit system of the second embodiment, FIG. 5 is a block diagram showing the electric circuit system of the third embodiment of the present invention, and FIG.
The figure is a partially cutaway side view showing the structure of a selection switch in a fourth embodiment of the present invention. 1... Endoscopy 1 2... Eyepiece 3... Image guide 4... Liquid crystal lens. 6... Transparent plate 8a, 8b... Convex lenses 9a, 9
b...Liquid crystal 14...Operation ring 13A, 13C
1,..., 13Cs, 14B... Contact 16... DC/AC converter 18... Battery 22... Light source device 23.
...A C/A C converter 31...Thermistor 32...Temperature correction circuit 4
1... Selection switch 43... Leaf spring Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 2 S Fig. 5 Happy Fig. 6

Claims (1)

[Scope of Claims] In an optical device that enables observation with the naked eye through an eyepiece in an eyepiece or photography via a photographing device attached to the eyepiece, an electric current is applied to at least a portion of the eyepiece. In addition to using a liquid crystal lens that uses liquid crystal whose focal length can be varied based on a change in the orientation of liquid crystal molecules in accordance with the applied voltage or magnetic field or its frequency, the liquid crystal lens is provided with an electrical means for varying the focal length of the liquid crystal lens. Features a diopter adjustment device using a liquid crystal.