JPH02184822A - Liquid crystal optical element - Google Patents

Abstract

PURPOSE:To allow the easy assembly of the optical element into the optical system of an endoscope, etc. without limitations by forming notches to at least either of transparent electrodes and spacer and forming the junctures of lead wires for impressing and regulating voltages or frequencies to the transparent electrodes in the spaces of the notches. CONSTITUTION:Transparent substrates 21, 22 and the spacer 23 to be inserted therein are notched respectively with at least at two points above and below and extending parts 25a, 26a of the respectively corresponding electrodes 25, 26 on one side intrude into the spacers of the respective notches 31, 32. Conductive adhesive agents 33, 34 respectively consisting of silver paste are packed into the respective notches 31, 32. The conductive adhesive agents 33, 34, therefore, form junctures 37, 38 connecting the lead wires 35, 36 which impress the voltages to the electrodes 25, 26 by electrically conducting to the extending parts 25a, 26a of the respective corresponding electrodes 25, 26. The easy assembly of the optical element in the optical system of the endoscope, etc., without limitations is possible in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a liquid crystal optical element such as a liquid crystal lens or a liquid crystal aperture that is incorporated into an observation optical system of an endoscope, for example.

[Prior Art] Liquid crystals have conventionally been used mainly as display elements. It is only recently that people have started thinking about applying it to liquid crystal optical elements such as liquid crystal lenses and liquid crystal apertures, and there are few proposals for specific implementation methods.

The shape of a typical liquid crystal display element is square (see from the optical axis direction).
Many of them are rectangular) shaped. In this way, a rectangular (quadrangular) shape was easy to implement in a device, and there were almost no restrictions. Further, the lead wires could be easily taken out from the electrodes from the space around the sides.

[Problems to be Solved by the Invention] However, when a liquid crystal is to be applied as an optical element such as a lens or an aperture, a shape that can be easily incorporated into the optical system of a conventional device is required. For example, when incorporating it into an objective optical system of an endoscope, it is preferable to make it into a microcircular shape with a diameter of 10 mm or less due to the structure of the part to be mounted. Therefore, it is extremely difficult to use the conventional rectangular shape as is, and it is impossible to make it compact.

Further, when the liquid crystal optical element is formed into a circular shape, there is a problem that there is no space for connecting the lead wire, and the lead wire protrudes, which is extremely inconvenient for mounting in a narrow space.

The present invention was made in view of the above-mentioned problems, and its purpose is to easily incorporate it into the optical system of an endoscope, etc. without any restrictions, and to provide a sufficient connection area with the lead wire. The object of the present invention is to provide a liquid crystal optical element that can be made compact.

[Means and effects for solving the problems] In order to solve the above problems, the present invention includes two substantially circular transparent substrates having transparent electrodes facing each other with a spacer interposed therebetween, and
In a liquid crystal optical element in which a liquid crystal is disposed between the two transparent substrates, a notch is formed in at least one of the transparent substrate and the spacer, and a voltage is applied to the transparent electrode within the space of the notch. A connection part for the lead wire is formed.

Even if the liquid crystal optical element is formed into an overall circular shape in this way, the connection portion of the lead wire that applies voltage to the transparent electrode can be accommodated within the overall circular area of the liquid crystal optical element.

Therefore, since the liquid crystal optical element can be formed into a compact circular shape, it can be easily incorporated into the optical system of an endoscope or the like without any restrictions, and a sufficient connection area for the lead wires can be secured.

[Embodiment] FIGS. 1 to 3 show a first embodiment of the present invention. FIG. 3 shows the distal end portion of the insertion portion 3 in an endoscope in which the liquid crystal lens element 1 shown enlarged in FIGS. 1 and 2 is incorporated into the objective optical system 2. The objective optical system 2 of the endoscope consists of a plurality of lenses 3 and 4, and is built into the distal end main body 5 of the insertion section 3. The rear lens 3 is fixed to the tip main body 5 via a lens frame (not shown) or directly. Further, the front lens 4 is detachably attached to the tip body 5 via a lens frame 6 screwed into the tip body 5. The objective optical system 2 forms an observation field image on the distal end surface of an image guide 8, and this formed optical image is transmitted to an eyepiece (not shown) through the image guide 8. The objective optical system 2 incorporates a liquid crystal lens element 1 located between a rear lens 3 and a front lens 4 and having a structure as described below. This liquid crystal lens element 1 is held in a cylindrical holder 9, and this holder 9 is tightly fitted into a fitting hole 11 in the tip body 5, and is tightened by a ring 12. Tightened and fixed. Lens frame 6 screwed into tip body 5 and tightening ring 12
When the liquid crystal lens element 1 is removed from the tip main body 5, the liquid crystal lens element 1 can be taken out together with the holder 9 from the opening.

Further, the tip main body 5 is provided with an illumination window glass 13 through which the illumination light transmitted through the light guide 14 is irradiated into the observation field.

On the other hand, the liquid crystal lens element 1 is constructed as shown in FIGS. 1 and 2. That is, two substantially circular transparent substrates 21 and 22 with the same diameter are connected to a ring-shaped spacer 2.
They are facing each other through 3.

The outer diameter of the ring-shaped spacer 23 is the same as that of the transparent substrates 21 and 22. The two transparent substrates 21 and 22 and the ring-shaped spacer 23 are arranged concentrically, and the liquid crystal 24 is placed in the space (cell) between the two transparent substrates 21 and 22 surrounded by the spacer 23. Filled. Electrodes 25 and 26 made of transparent conductive films are provided on both the front and rear surfaces of the liquid crystal 24. Note that an alignment film is provided on the surfaces of the electrodes 25 and 26 in contact with the liquid crystal 24, if necessary.

Further, the liquid crystal 24 enters into four spherical parts 27 formed at corresponding positions on the front transparent substrate 21 and is formed into a convex lens shape as a whole, thereby forming a liquid crystal lens part 28.

Incidentally, the refractive power of this liquid crystal lens section 28 changes depending on the refractive index n of the liquid crystal 24 constituting it. The refractive index n of the liquid crystal 24 can be changed using the birefringence of the liquid crystal 24. In other words, this LCD 2
Depending on the value of the voltage applied to 4, the alignment of liquid crystal molecules changes due to their dielectric anisotropy, and the refractive index n changes. Therefore, by changing the applied voltage, the refractive power changes, and the focal position moves accordingly.

Note that two deflection plates are attached to the rear surface of the rear transparent substrate 22. This deflection plate 29 transmits light having an amplitude in a certain direction. Therefore, the contrast of the observed image is improved.

The transparent substrate 21.22 and the spacer 23 sandwiched therebetween are cut out at least in two places, upper and lower. Within the space are extending portions 25a, 26a of one electrode 25, 26 corresponding to each other.
has entered. Each of the notches 31 and 32 is filled with a conductive adhesive 33 and 34 made of silver paste or the like. For this reason, each conductive adhesive 33
．． 34 are extensions 25 of the corresponding electrodes 25 and 26, respectively.
a, a connecting portion 3 for connecting a lead wire 35° 36 that is electrically conductive to the electrodes 25 and 26a and applies a voltage to each of the electrodes 25 and 26;
7.38 is formed.

The lead wires 35 and 36 have a diameter of, for example, 1 mm or less, and are led out through insertion holes 9a and 9b formed through the holder 9, as shown in FIG. 3, and connected to a control drive unit (not shown). It has become so.

When connecting this lead wire 36.37 to the electrode 25.26, the transparent substrates 21, 22, the spacer 23, and the electrode 2
5. After pasting and assembling the 26 etc., cut out part 31
．． At the connection parts 37' and 38 formed by the inside of the electrode 25.26, conductive adhesive 33.34 is used on the extension parts 25a and 26a of the electrode 25.26, and the lead wires 35 and 36 are connected to the corresponding electrode 25. Can be electrically connected.

Since the connecting portions 37 and 38 are formed at a location away from the liquid crystal 24, they do not interfere with the optical function of the liquid crystal 24, while the connecting portions 37 and 38 are formed at a location separate from the transparent substrates 21 and 24.
2 and the peripheral portions of the spacer 23 are removed.
The overall outer shape of the liquid crystal lens element 1 is compact and circular, with no protruding parts. As a result, it can be easily and firmly incorporated into the distal end portion of the insertion section 3 in the above-mentioned endoscope. For example, it can be loaded securely and compactly by coming into close contact with the inner surface of the holder 9.

Therefore, even the insertion section 3 of the endoscope, which must be assembled together with other built-in objects, can be assembled relatively easily. Note that the cutout portions 31 and 32 may be located anywhere on the circumference.

4 and 5 show a second embodiment of the present invention. This embodiment is also an example in which a liquid crystal lens element 40 is configured as a liquid crystal optical element in the same way as the first embodiment.
5, 26, the liquid crystal lens section 28, and the deflection plate 29 are similarly constructed.

However, in this embodiment, the notches 31 and 32 are formed only in the transparent substrates 21 and 22, and not in the spacers 23. In addition, each notch 31, 32 has V as shown in FIG.
It is formed into a letter shape. And this transparent substrate 21.2
The extending portions 25a, 26 of the corresponding electrodes 25.26 are located within the spaces of the notches 31.32 formed only in the electrodes 25.2.
A is included. Similarly to the above, each of the notches 31 and 32 is filled with conductive adhesive 33 and 34.
and connect lead wires 35 and 36.

In other words, the connecting portion 37 electrically connects the lead wire 35.36 to the extension portions 25a, 26a of each electrode 25.26 using the conductive adhesive 33.34 in the space of the cutout portion 31; .38 is formed.

Therefore, this embodiment also provides the same effects as described above. Further, in this embodiment, the notch portion 31.
32 is formed only on the transparent substrates 21 and 22, processing and assembly thereof are easy. Furthermore, the notch 31
．． Since 32 is not formed on the spacer 23, the liquid crystal 24
The effective diameter of the cell containing the can be increased.

Note that the notches 31 and 32 may be located anywhere on the circumference of the transparent substrates 21 and 22.

FIGS. 6 and 7 show a third embodiment of the present invention. This embodiment is an example of a liquid crystal aperture element 41 as a liquid crystal optical element.

This liquid crystal aperture element 41 is constructed as follows. That is, two approximately circular transparent substrates 21 and 22 with the same diameter
are opposed to each other with a ring-shaped spacer 23 interposed therebetween. The outer diameter of the spacer 23 is the same as that of the transparent substrate 21.22. The two transparent substrates 21.22 and the ring-shaped spacer 23 are arranged concentrically, and a space (cell) is formed between the two transparent substrates 21.22 surrounded by the spacer 23.
is filled with liquid crystal 24. Furthermore, electrodes 25 and 26 made of transparent conductive films are provided on both the front and rear surfaces of the liquid crystal 24.

An alignment film (not shown) is provided on the surfaces of the electrodes 25 and 26 in contact with the liquid crystal 24, if necessary. Due to this alignment film, the liquid crystal molecules of the liquid crystal 24 are twisted by 90° from one electrode 25 to the other electrode 26 when no voltage is applied.

Furthermore, the central portion of the front electrode 25 is open, so that even if a voltage is applied to the electrodes 25, 26, the opening 42
No action is performed on the liquid crystal 24 in the portion corresponding to the area.

On the other hand, the front surface of the front transparent substrate 21 and the rear transparent substrate 22
Deflection plates 29 and 30 are respectively attached to the rear surfaces of the . The deflection plates 29 and 30 are selected depending on the alignment of the liquid crystal molecules of the liquid crystal 24, and the front deflection plate 29 corresponds to the alignment direction of the liquid crystal molecules on the front end side when no voltage is applied between the electrodes 25 and 26. A material is selected that transmits light with an amplitude vibrating in the same direction and absorbs light with an amplitude in a direction perpendicular to it, and the rear deflection plate 30 has a deflection direction rotated by 90' with respect to the front deflection plate 29. is selected.

Further, the circumferential portion of the spacer 23 sandwiched between the transparent substrates 21 and 22 is cut out, for example, at the upper and lower 2 portions, and each of the upper and lower cutout portions 31 and 32
In the space of each corresponding one electrode 25.2.
6 extension portion 25a.

26a has entered. Furthermore, each notch 31
．． Each of the conductive adhesives 33 and 34 made of silver paste or the like is filled in each of the conductive adhesives 33 and 32 .

For this purpose, each conductive adhesive 33.34 has a lead wire 35.36 that is electrically connected to the extension portions 25a, 26a of the corresponding electrode 25.26 and applies a voltage to each of the electrodes 25.26. Connecting portions 37 and 38 are formed. The lead wires 35 and 36 are, for example, similar to those in the first embodiment, having insertion holes 9a formed through the holder 9 as shown in FIG.

9b, and is connected to a control drive section (not shown).

By the way, when connecting the lead wires 35° 36 to each electrode 25.26, after assembling the transparent substrates 21, 22, spacer 23, electrode 25.26, etc., the extension portion 25a of the electrode 25.26 is .

Lead wires 35, 36 are electrically connected to corresponding electrodes 25, 26 using conductive adhesives 33, 34 on 26a, respectively. Incidentally, as shown in FIGS. 6 and 7, the conductive adhesive 33 and 34 protrude slightly from the outer circumferential surface of the spacer 23, but the amount is small compared to the size of the notches 31 and 32. The outer circumferential shape can be considered to be approximately circular.

In this liquid crystal diaphragm 41, the electrode 25.2
When no voltage is applied between 6 and 6, light passes through the entire surface of liquid crystal 24. Further, when a voltage is applied between the electrodes 25 and 26, the alignment of liquid crystal molecules in the portion of the liquid crystal 24 excluding the portion corresponding to the aperture 42 becomes a homeotropic alignment. Therefore, light passing through this array cannot pass through the rear deflecting plate 30. In other words, the overall amount of transmitted light is reduced.

In the configuration of this embodiment, similarly to each of the above embodiments,
Since the connecting portions 37 and 38 are formed at a location away from the liquid crystal 24, they do not interfere with the optical function of the liquid crystal 24. On the other hand, since the connecting portions 37 and 38 are formed by removing the peripheral portion of the spacer 23, The overall outer shape of the liquid crystal diaphragm element 1 is compact and circular, and as a result, it can be easily incorporated into the distal end portion of the insertion section 3 of the endoscope as described above, for example. Therefore, the insertion section 3 of the endoscope must be assembled with other built-in items.
However, it can be installed relatively easily. In this embodiment as well, the notches 31 and 32 may be located anywhere on the circumference of the spacer 23. In addition, the notch portions 31 and 32
may be formed over both the transparent substrates 21 and 22 or the spacer 23.

Note that an adhesive mixed with microspheres may be used as the spacer in the configurations of the above embodiments, and may be sandwiched between the transparent substrates, and the space between the transparent substrates may be determined by the diameter of the microspheres.

[Effects of the Invention] As explained above, according to the present invention, even if the liquid crystal optical element is formed into a circular shape as a whole, the connection portion of the lead wire that applies voltage to the transparent electrode is connected to the liquid crystal optical element. It can be fully formed by taking it within a circular area as a whole. Therefore, since the liquid crystal optical element can be configured in a compact circular shape as a whole, it can be easily incorporated into an optical system in a narrow space such as an endoscope without any restrictions, and the connection part of the lead wire can be made sufficiently secure. Can be secured.

[Brief explanation of the drawing]

1 to 3 show a first embodiment of the present invention, FIG. 1 is a side sectional view of the distal end of an endoscope insertion section incorporating a liquid crystal lens element, and FIG. 3 is a front sectional view of the liquid crystal lens element, FIGS. 4 and 5 show a second embodiment of the present invention, and FIG. 4 is a side sectional view of the liquid crystal lens element, and FIG. FIG. 5 is a front sectional view of the liquid crystal lens element, FIGS. 6 and 7 show a third embodiment of the present invention, FIG. 6 is a side sectional view of the liquid crystal aperture element, and FIG. 7 is a front sectional view of the liquid crystal lens element. FIG. 3 is a front sectional view of the diaphragm element. DESCRIPTION OF SYMBOLS 1...Liquid crystal lens element, 2...Objective optical system, 21°22...Transparent substrate, 23...Spacer, 24...
Liquid crystal, 31.32... Notch, 33.34... Adhesive, 35.36... Lead wire, 37.38... Connection part, 40... Liquid crystal lens element, 41...・Liquid crystal aperture element. Applicant's representative Patent attorney Atsushi Tsuboi WE4 Figure 4 + 4 Figure 3 Contents of the amendment (1. Indication of the 1° case in which the name of the invention is amended to "electro-optical device" Name 3゜Relationship with the electro-optical element correction case Patent applicant (037) Olympus Optical Industry Co., Ltd. 4, agent 3-7-2 Kasumigaseki, Chiyoda-ku, Tokyo (2) Patent claim in the specification Correct the range as shown in the attached sheet. (3) Correct "to liquid crystal optical elements" in line 16 of page 1 of the specification to "to electro-optical elements such as liquid crystal optical elements." (4) Correct the text in line 16 of page 1 of the specification. On the 19th line of the page, before "Liquid crystals are conventionally used," it says, "Liquid crystals are a typical electro-optical element.
Insert this. (5) Correct "insert section 3" on page 4, line 10 of the specification to "insert section A." (6) Correct "insert section 3" on page 4, line 12 of the specification to "insert section A." (7) Change "insert part 3" on page 9, line 4 of the specification to insert part A.
”. (8) Amend Figure 3 of the drawing as shown in the attached sheet. 2. Scope of Claims An electro-optical element comprising two substantially circular transparent substrates having transparent electrodes facing each other with a spacer interposed therebetween, and an electro-optic material disposed between the two transparent substrates. A notch is formed in at least one of the transparent substrate and the spacer, and a lead wire connection part for applying and adjusting a voltage or frequency frequency to the transparent electrode is formed in the space of the notch. Electro-optical element.

Claims (1)

[Claims] In a liquid crystal optical element in which two approximately circular transparent substrates having transparent electrodes are opposed to each other with a spacer interposed therebetween, and a liquid crystal is disposed between the two transparent substrates, at least one of the transparent substrates and the spacer is provided. 1. A liquid crystal optical element, characterized in that a notch is formed, and a connection part for a lead wire for applying a voltage to the transparent electrode is formed in the space of the notch.