WO2009119276A1 - Method and system for adjusting electrode position - Google Patents

Abstract

First and second optical crystal plates each of which has a surface whereupon a plurality of linear electrodes are formed at equal intervals are laminated such that the longitudinal directions of the linear electrodes match, a luminous flux is applied to the linear electrodes formed on the first and the second optical crystal plates, and in the state where the first and the second optical crystals are laminated, at least the first optical crystal or the second optical crystal is shifted in a direction which intersects with the longitudinal direction, then, the intensity of transmitted light which passed through the first and the second optical crystals is detected, while changing relative positions of the linear electrodes between the first and the second optical crystals (steps (S10-S12)). A shift position where the intensity of the transmitted light is maximum is permitted to be an optimum position for the first and the second optical crystal plates (step (S13)).

Description

Electrode position adjusting method and system

The present invention relates to an optical switch that switches between a light transmitting state and a light reflecting state.

An optical switch that switches between a transmissive state and a reflective state using an electro-optic effect is disclosed in Patent Document 1 (Japanese Patent No. 2666805 (Japanese Patent Laid-Open No. 1-214827)). The optical switch includes an optical waveguide layer having an electro-optic effect, and first and second electrode groups provided in the optical waveguide layer. Each of the first and second electrode groups is composed of a plurality of plate-like electrodes extending in the thickness direction of the optical waveguide layer. Each plate electrode is arranged at a constant interval. Each of the first electrode group and the second electrode group has a comb shape on a surface intersecting the thickness direction of the optical waveguide layer, and plate electrodes corresponding to the comb teeth are alternately arranged. Has been placed.

In this optical switch, a change in refractive index occurs between adjacent plate electrodes by applying a voltage between the first and second electrode groups. As a result, a periodic refractive index change occurs in the optical waveguide layer. A portion where the periodic refractive index change functions as a diffraction grating, and incident light is reflected. On the other hand, when the voltage application to the first and second electrode groups is stopped, the function as the diffraction grating is lost, and the incident light is transmitted.

Demand for further miniaturization and power saving of optical switches. By reducing the area (capacitance) of the electrode, the operating voltage can be lowered, thereby saving power. Further, the optical switch can be miniaturized by reducing the area of the electrode. However, in the optical switch described in Patent Document 1, since a plurality of plate electrodes having a large area are used to form a diffraction grating, it is difficult to achieve such downsizing and power saving. . If the area of the plate electrode is reduced, the region in which the periodic refractive index change occurs is reduced, and as a result, a sufficient function as a diffraction grating may not be obtained.

By the way, in the case of a general optical switch used in optical communication or the like, the required extinction ratio is about 10: 1, but the extinction ratio is not sufficient when considering application to an image display device. For this reason, further improvement of the extinction ratio is also demanded.

So far, no technology has been proposed for realizing an optical switch capable of reducing the size and power consumption and improving the extinction ratio.

An object of the present invention is to provide an electrode position adjusting method and system for an optical switch that can solve the above-mentioned problems.

In order to achieve the above object, the electrode position adjustment method of the present invention comprises:
First and second optical crystals each having a surface on which a plurality of linear electrodes are formed at equal intervals are stacked so that the longitudinal directions of the plurality of linear electrodes coincide with each other. Irradiating a region including the plurality of linear electrodes formed on the optical crystal 2 with a light beam;
In a state in which the first and second optical crystals are stacked, at least one of the first and second optical crystals is moved in a direction intersecting the longitudinal direction, and the first and second optical crystals are Detecting the intensity of transmitted light that has passed through the first and second optical crystals while changing the relative position of the plurality of linear electrodes between each other,
The movement position where the intensity of the detected transmitted light is highest is set as the optimum position of the first and second optical crystals.

The electrode position adjustment system of the present invention is
First and second optical crystals each having a surface in which a plurality of linear electrodes are formed at equal intervals are respectively held in a stacked state so that the longitudinal directions of the plurality of linear electrodes coincide with each other. And a second stage,
A light irradiating unit that irradiates a light beam onto a region including the plurality of linear electrodes formed on the first and second optical crystals held on the first and second stages;
A light receiving portion for detecting transmitted light that has passed through the first and second optical crystals;
Relative positions of the plurality of linear electrodes between the first and second optical crystals by moving at least one of the first and second stages in a direction crossing the longitudinal direction A control unit that monitors the output level of the light receiving unit while changing
The control unit is characterized in that the moving position where the output level of the light receiving unit is the highest is determined as the optimum position of the first and second optical crystals.

It is a top view of the principal part of the optical switch with which the electrode position adjustment method of this invention is applied. It is sectional drawing by the AA line of FIG. 1A. It is a schematic diagram which shows the positional relationship of the electrode part in the advancing direction of incident light of the optical switch shown to FIG. 1A. It is a schematic diagram which shows the refractive index change area | region formed at the time of the electric field application of the optical switch shown to FIG. 1A. It is a schematic diagram which shows the state where the position of the electrode part of the optical switch shown to FIG. 1A is not appropriate. It is a schematic diagram which shows the state in which the position of the electrode part of the optical switch shown to FIG. 1A is appropriate. It is a block diagram which shows the structure of the system for enforcing the electrode position adjustment method which is the 1st Embodiment of this invention. It is a flowchart which shows one procedure of the electrode position adjustment method which is the 1st Embodiment of this invention. It is a schematic diagram for demonstrating the predetermined conditions in the case of setting an initial position. It is a wave form diagram which shows an example of the 1st and 2nd waveform. It is a block diagram which shows the structure of the system for enforcing the electrode position adjustment method which is the 2nd Embodiment of this invention. It is a flowchart which shows one procedure of the electrode position adjustment method which is the 2nd Embodiment of this invention. It is a schematic diagram for demonstrating the 1st example of arrangement | positioning in the case of performing the electrode position adjustment method of this invention. It is a schematic diagram for demonstrating the 1st example of arrangement | positioning in the case of performing the electrode position adjustment method of this invention. It is a schematic diagram for demonstrating the 2nd example of arrangement | positioning in the case of performing the electrode position adjustment method of this invention. It is a schematic diagram for demonstrating the 2nd example of arrangement | positioning in the case of performing the electrode position adjustment method of this invention. It is sectional process drawing which shows one procedure of the electrode formation method of an optical switch. It is sectional process drawing which shows one procedure of the electrode formation method of an optical switch. It is sectional process drawing which shows one procedure of the electrode formation method of an optical switch. It is sectional process drawing which shows one procedure of the electrode formation method of an optical switch. It is sectional process drawing which shows one procedure of the electrode formation method of an optical switch. It is sectional process drawing which shows one procedure of the electrode formation method of an optical switch. It is sectional process drawing which shows one procedure of the electrode formation method of an optical switch. It is sectional process drawing which shows one procedure of the electrode formation method of an optical switch. It is sectional process drawing which shows one procedure of the electrode formation method of an optical switch. It is a schematic diagram which shows an example of an image display apparatus. 1 is a schematic diagram illustrating an example of an image forming apparatus.

Explanation of symbols

10 to 12 Optical crystal plates 13a, 13b, 14a, 14b Electrode unit 20 Control unit 21 Optimal position determination unit 22 Stage control unit 30 Light receiving unit 40 Display unit 50, 51 Stage 60 Light irradiation unit

Next, an embodiment of the present invention will be described with reference to the drawings.

First, the configuration of an optical switch to which the electrode position adjusting method of the present invention is applied will be described.

1A is a top view of the main part of an optical switch to which the electrode position adjusting method of the present invention is applied, and FIG. 1B is a cross-sectional view taken along the line AA of FIG. 1A.

As shown in FIGS. 1A and 1B, an optical switch includes an optical crystal plate 10, an optical crystal plate 11 having electrode portions 13a and 13b formed on the surface, and an optical crystal having electrode portions 14a and 14b formed on the surface. It has a structure in which the plate 12 is laminated. The optical crystal plates 10 to 12 are made of a crystal having an electro-optic effect (electro-optic crystal).

Each of the electrode portions 13a and 13b is a comb-shaped electrode having a plurality of linear electrodes arranged at equal intervals and having a main cross section having the maximum area in the same plane. In the electrode portion 13a and the electrode portion 13b, the linear electrodes are alternately arranged, and the intervals between the linear electrodes are equal. The electrode portions 14a and 14b are also comb-shaped electrodes similar to the electrode portions 13a and 13b, and the linear electrodes are alternately arranged. The intervals between the linear electrodes of the electrode portions 14a and 14b are equal intervals, and are the same as the intervals between the linear electrodes of the electrode portions 13a and 13b.

The optical crystal plate 10 is attached to the surface of the optical crystal plate 11 so as to cover the portion where the linear electrodes corresponding to the comb teeth of the electrode portions 13a and 13b are formed. The optical crystal plate 11 to which the optical crystal plate 10 is attached is attached to the surface of the optical crystal plate 12 so as to cover the portion where the linear electrodes corresponding to the comb teeth of the electrode portions 14a and 14b are formed.

FIG. 1A is a perspective view showing a state in which the electrode portions 13a and 13b formed on the surface of the optical crystal plate 11 are viewed from the optical crystal plate 10 side. When viewed from the direction perpendicular to the surface of the optical crystal plate 10, the first electrode formation region composed of the electrode portions 13a and 13b is slightly shifted from the second electrode formation region composed of the electrode portions 14a and 14b. Is formed. However, as shown in FIG. 1B, when viewed from the direction perpendicular to the cross section of the optical crystal plates 10 to 12 cut along the line AA in FIG. 1A, the position of each linear electrode of the electrode portions 13a and 13b, and the electrode The positions of the linear electrodes of the portions 14a and 14b are the same.

FIG. 1C is a schematic diagram showing the positional relationship between the electrode portions 13a and 13b and the electrode portions 14a and 14b in the traveling direction of incident light. The cross section shown in FIG. 1C is a cross section taken along line BB in FIG. 1A.

As shown in FIG. 1C, the first electrode formation region composed of the electrode portions 13a and 13b and the second electrode formation region composed of the electrode portions 14a and 14b are sequentially arranged in the traveling direction of the incident light. That is, the first and second electrode formation regions are located on the optical path. When the first and second electrode formation regions are viewed along the traveling direction of the incident light 15, the first and second electrode formation regions are formed by forming electrode surfaces (or electrode portions) of the electrode portions of the mutual regions. Are stacked so that the parallel surfaces are parallel. Further, when viewed along the traveling direction of the incident light 15, the positions of the linear electrodes of the electrode portions 13a and 13b coincide with the positions of the linear electrodes of the electrode portions 14a and 14b.

An optical switch is formed by laminating the optical crystal plates 10 to 12 shown in FIGS. 1A to 1C at high temperature and high pressure. The optical crystal plates 10 to 12 bonded together under high temperature and high pressure can be regarded as one optical crystal (specifically, an electro-optical crystal). That is, by bonding the optical crystal plates 10 to 12 under high temperature and high pressure, an electro-optical crystal having an electrode portion inside can be formed.

In this optical switch, when a voltage is applied between the electrode portions 13a and 13b, the refractive index of the crystal in the vicinity of the electrode including the electrode portions 13a and 13b changes due to the electro-optic effect. Similarly, when a voltage is applied between the electrode portions 14a and 14b, the refractive index of the crystal in the vicinity of the electrode including the electrode portions 14a and 14b changes due to the electro-optic effect.

FIG. 2 schematically shows a refractive index change region formed in the electrode vicinity region including the electrode portions 13a and 13b. When a voltage is applied between the electrode portions 13a and 13b, an electric field is generated between adjacent linear electrodes, and the refractive index of the crystal in the electrode vicinity region including each linear electrode changes due to the electric field. The region where the refractive index has changed is the refractive index changing region 16 shown in FIG. Incident light is totally reflected at the interface (refractive index interface) between the refractive index changing region 16 and the surrounding crystal region. The incident angle of the incident light (same as the incident angle θ shown in FIG. 1C) is desirably set so as to satisfy a condition that allows total reflection at this interface.

Note that FIG. 2 shows a state in which incident light enters the refractive index change region from the left side toward the drawing and the reflected light goes to the right side. However, in order to further improve the light utilization efficiency, Is preferably incident on the refractive index changing region from the front side (or back side) toward the drawing, and the reflected light is directed toward the back side (or front side).

In addition, when an opaque material is used as the electrode, the electrode itself blocks a part of the incident light, so that the light use efficiency is reduced accordingly. In order to improve this point, the use efficiency of light can be improved by making the electrode a transparent electrode.

When a voltage is applied to the electrode portions 13a and 13b, the refractive index change region 16 is formed, so that the incident light is totally reflected at the interface of the refractive index change region 16. On the other hand, when the supply of voltage to the electrode portions 13a and 13b is stopped, the refractive index changing region 16 is not formed, and the incident light passes through the electrode portions 13a and 13b as it is. Similarly, in the regions of the electrode portions 14a and 14b, when a voltage is applied, a refractive index change region is formed, and incident light is totally reflected at the interface of the refractive index change region. When the supply of voltage to the electrode portions 14a and 14b is stopped, the refractive index change region is not formed, and incident light passes through the electrode portions 14a and 14b as it is.

In the switch operation of the optical switch, it is possible to switch between a first state in which incident light is reflected and a second state in which incident light is transmitted. In the first state, a voltage is applied to each of the electrode portions 13a and 13b and the electrode portions 14a and 14b to form refractive index change regions, and incident light is reflected in these refractive index change regions. In the second state, voltage supply to the electrode portions 13a and 13b and the electrode portions 14a and 14b is stopped. By stopping the voltage supply, the refractive index change due to the electro-optic effect does not occur in each region including the electrode portions 13a and 13b and the electrode portions 14a and 14b, so that the incident light passes through these regions.

The interface of the refractive index changing region partially includes a region that does not satisfy the total reflection condition, and a part of the incident light is transmitted through this region. The range of the region that does not satisfy the total reflection condition depends on the interval between the linear electrodes and the magnitude of the applied voltage (the magnitude of the electric field). In the optical switch described above, incident light is reflected at the interface of the first refractive index change region formed by applying a voltage to the electrode portions 13a and 13b, and further, a voltage is applied to the electrode portions 14a and 14b. The light transmitted through the first refractive index change region is reflected at the interface of the second refractive index change region formed in this way. Thereby, it is possible to obtain a high extinction ratio. The extinction ratio can be further improved by setting the number of electrode portions (number of refractive index change regions) formed along the traveling direction of incident light to three or more. However, when the number of refractive index changing regions is increased, the number and capacity of the electrodes increase accordingly, which is not desirable from the viewpoint of power saving and miniaturization. It is desirable to determine the number of refractive index changing regions in consideration of the relationship between the extinction ratio and power saving and miniaturization.

Also, for example, when a translucent or opaque electrode material is used for the linear electrode, part of the incident light is blocked by the linear electrode. In the second state where incident light is transmitted when the positions of the linear electrodes of the electrode portions 13a and 13b and the linear electrodes of the electrode portions 14a and 14b are not appropriate, the regions including the linear electrodes of the electrode portions 13a and 13b Since part of the light transmitted through the light is blocked by the electrode portions 14a and 14b, the extinction ratio is lowered.

FIG. 3A is a schematic diagram illustrating a state where the positions of the linear electrodes of the electrode portions 13a and 13b and the linear electrodes of the electrode portions 14a and 14b are not appropriate. FIG. 3A shows the interface between the linear electrodes of the electrode portions 13a and 13b and the linear electrodes of the electrode portions 14a and 14b when viewed from the direction perpendicular to the cross section taken along the line AA in FIG. 1A. The positional relationship with respect to the incident light is shown. In this example, the linear electrodes of the electrode portions 13a and 13b are formed at positions shifted in the direction intersecting the longitudinal direction of the linear electrodes with respect to the linear electrodes of the electrode portions 14a and 14b. For this reason, in the second state in which the incident light is transmitted, a part of the light transmitted through the region including the linear electrodes of the electrode portions 13a and 13b is blocked by the electrode portions 14a and 14b.

A high extinction ratio can be obtained by appropriately matching the positions of the linear electrodes of the electrode portions 13a and 13b and the linear electrodes of the electrode portions 14a and 14b with respect to the incident light. FIG. 3B is a schematic diagram illustrating a state where the positions of the linear electrodes of the electrode portions 13a and 13b and the linear electrodes of the electrode portions 14a and 14b are appropriate. FIG. 3B shows the interface between the linear electrodes of the electrode portions 13a and 13b and the linear electrodes of the electrode portions 14a and 14b when viewed from the direction perpendicular to the cross section of the line AA in FIG. 1A. The positional relationship with respect to the incident light is shown. In this example, the positions of the linear electrodes of the electrode portions 13a and 13b and the linear electrodes of the electrode portions 14a and 14b with respect to the incident light coincide with each other. For this reason, in the second state where incident light is transmitted, most of the light transmitted through the regions including the linear electrodes of the electrode portions 13a and 13b is transmitted through the region including the electrode portions 14a and 14b.

As shown in FIG. 3B, by setting the electrode position appropriately, in the second state where incident light is transmitted, most of the light transmitted through the regions including the linear electrodes of the electrode portions 13a and 13b is the electrode. Since the region including each linear electrode of the portions 14a and 14b is transmitted, a high extinction ratio can be obtained.

The electrode position adjusting method according to the present invention provides the position of the linear electrodes of the electrode portions 13a and 13b and the linear electrodes of the electrode portions 14a and 14b with respect to incident light in the optical switch as shown in FIGS. 1A to 1C. This is a method of adjusting to an optimal position. According to one aspect of the electrode position adjusting method of the present invention, the first and second optical crystals having a surface on which a plurality of linear electrodes are formed at equal intervals are arranged in the longitudinal direction of each of the plurality of linear electrodes. Are laminated so that they coincide with each other, and a light beam is irradiated onto a region including the plurality of linear electrodes formed in the first and second optical crystals. In this state, at least one of the first and second optical crystals is moved in a direction crossing the longitudinal direction, and the plurality of linear electrodes between the first and second optical crystals are arranged. While changing the relative position, the intensity of the transmitted light that has passed through the first and second optical crystals is detected. The movement position where the intensity of the transmitted light detected is the highest is determined as the optimum position of the first and second optical crystals.

Hereinafter, embodiments of the electrode position adjusting method of the present invention will be specifically described.

(First embodiment)
FIG. 4 is a block diagram showing the configuration of a system for carrying out the electrode position adjusting method according to the first embodiment of the present invention. Referring to FIG. 4, the electrode position adjustment system includes a control unit 20, a light receiving unit 30, a display unit 40, stages 50 and 51, a light irradiation unit 60, and an input unit 70.

Stages 50 and 51 are stages capable of one-dimensional or two-dimensional movement. The laminated optical crystal plates 10 and 11 shown in FIG. 1A are fixed to the stage 50, and the optical crystal plate 12 shown in FIG. 1A is fixed to the stage 51. The stage 50 is movable in a direction intersecting with the longitudinal direction of each linear electrode of the electrode portions 13a and 13b, and the stage 51 is movable in a direction intersecting with the longitudinal direction of each linear electrode of the electrode portions 14a and 14b. is there. Here, the direction intersecting the longitudinal direction of the linear electrode is a direction along line AA in FIG. 1A. The back surface of the optical crystal plate 11 fixed to the stage 50 (the surface opposite to the surface on which the electrode portions 13a and 13b are formed) is the surface of the optical crystal plate 12 fixed to the stage 51 (the electrode portions 14a and 14b are The optical crystal plate can be moved by the stages 50 and 51 in a state in which these surfaces are in contact with each other (surface formed). Further, the optical crystal plates 11 and 12 are held by the stages 50 and 51 so that the longitudinal directions of the linear electrodes coincide with each other.

The display unit 40 is a display device such as an LCD (Liquid Crystal Display). The input unit 70 is an operation unit on which a plurality of keys are arranged, and the operator can freely input data necessary for operating the system and adjust the positions of the stages 50 and 51 through the input unit 70. It can be carried out.

The light irradiation unit 60 irradiates the optical crystal plates 10 to 12 fixed to the stages 50 and 51 with a parallel light beam. The light from the light irradiation unit 60 enters each interface of the optical crystal plates 10 to 12 from the same direction as the incident light shown in FIG. That is, the incident angle of the light from the light irradiation unit 60 at each interface of the optical crystal plates 10 to 12 is the incident angle θ of the incident light shown in FIG.

The light receiving unit 30 receives light transmitted from the light irradiation unit 60 through the region including the electrode units 13a and 13b and the region including the electrode units 14a and 14b. The light receiving unit 30 is, for example, a photodiode, and outputs a signal having a magnitude corresponding to the light receiving level. The output signal of the light receiving unit 30 is supplied to the control unit 20.

The control unit 20 includes an optimum position determination unit 21 and a stage control unit 22. The stage control unit 23 performs movement control of the stages 50 and 51. For example, the stage control unit 22 receives an operator input through the input unit 70, and moves the stages 50 and 51 in accordance with the input instruction. With this control, the operator can adjust the positions of the stages 50 and 51. The stage control unit 22 moves the stages 50 and 51 based on the movement instruction signal from the optimum position determination unit 22.

The optimum position determination unit 21 passes one of the stages 50 and 51 through the stage control unit 22 in the second direction which is the first direction and the opposite direction in the direction intersecting the longitudinal direction of the linear electrodes. Move by a predetermined amount. The predetermined movement amount is half of the interval between the linear electrodes.

The optimum position determination unit 21 receives the output signal of the light receiving unit 30, and shows a first change in the level of the received signal when the stage is moved by a predetermined amount from the initial position state in the first direction. And a second waveform indicating a change in level of the received signal when the stage is moved by a predetermined amount in the second direction from the initial position. The operator performs a stage moving operation through the input unit 70 to set a position between the electrodes as a guide. The reference position set by the operator is the initial position.

Furthermore, the optimum position determination unit 21 optimizes the positions of the linear electrodes of the electrode parts 13a and 13b and the linear electrodes of the electrode parts 14a and 14b at the highest level in the first and second waveforms. Judge as position.

FIG. 5 is a flowchart showing a procedure of the electrode position adjusting method according to the first embodiment of the present invention using the position adjusting system of FIG.

Referring to FIG. 5, first, the stage control unit 22 receives an operator input through the input unit 70 and moves the stages 50 and 51 in accordance with the input instruction. By this movement control, a position (initial position) between the electrodes that serves as a guide is set (step S10).

Next, the optimum position determination unit 21 moves the stage 51 from the initial position state in the first direction by a predetermined amount, and obtains a first waveform indicating the level change of the received signal from the light receiving unit 30 at that time. (Step S11). Further, the optimum position determination unit 21 moves the stage 51 from the initial position state in the second direction by a predetermined amount, and acquires a second waveform indicating the level change of the received signal from the light receiving unit 30 at that time. (Step S12).

Finally, the optimum position determination unit 21 examines the highest point in the acquired first and second waveforms, and the linear electrodes of the electrode portions 13a and 13b and the linear shapes of the electrode portions 14a and 14b at that point. The position with the electrode is determined as the optimum position (step S13).

According to the above-described electrode position adjustment procedure, if the initial position is set so as to satisfy a predetermined condition, the positional relationship between the linear electrodes of the electrode portions 13a and 13b and the linear electrodes of the electrode portions 14a and 14b is always set. The optimal positional relationship shown in FIG. 3B can be set.

FIG. 6 is a schematic diagram for explaining predetermined conditions when setting the initial position. FIG. 6 shows the interface between the linear electrodes of the electrode portions 13a and 13b and the linear electrodes of the electrode portions 14a and 14b when viewed from the direction perpendicular to the cross section of the line AA in FIG. 1A. The position relative to the incident light is shown. The interval D1 indicates the size of the interval between adjacent linear electrodes, and the shift amount D2 indicates the shift amount of each linear electrode of the electrode portions 13a and 13b with respect to each linear electrode of the electrode portions 14a and 14b. In this case, the predetermined condition is given by “D2 <D1 / 2”.

If the initial position is set so as to satisfy the predetermined condition “D2 <D1 / 2”, the stage is moved by a predetermined amount (= D1 / 2) in the first direction, or the second direction In any case where the stage is moved by a predetermined amount (= D1 ÷ 2), the state of the optimum position shown in FIG. 3B is included. In this case, the levels of the first and second waveforms become maximum at the timing when the optimum position is reached. Therefore, the optimum electrode position can be known by examining the maximum levels (peaks) in the first and second waveforms.

FIG. 7 shows an example of the first and second waveforms. FIG. 7 shows the first and second waveforms when the state shown in FIG. 6 is set as the initial position. The vertical axis represents the detected light intensity (received signal level). The horizontal axis indicates the amount of stage movement. A first waveform obtained when the stage moves by a predetermined amount (= D1 ÷ 2) in the first direction, and a case where the stage moves by a predetermined amount (= D1 ÷ 2) in the second direction. The obtained second waveforms are shown in FIG. In this example, the state of the optimum position shown in FIG. 3B is included when the stage moves by a predetermined amount (= D1 / 2) in the first direction. Therefore, the first waveform includes the maximum level (peak). The maximum level (peak) of the first waveform is detected, and the electrode position at that time is the optimum position P. In this way, the optimum positions of the linear electrodes of the electrode portions 13a and 13b and the linear electrodes of the electrode portions 14a and 14b can be known.

When the initial position is set under the condition of “D2 ≧ D1 / 2”, the electrode positions at the maximum levels (peaks) of the first and second waveforms are determined by the respective linear electrodes of the electrode portions 13a and 13b. It will be in the state which shifted | deviated more than the space | interval D with respect to each linear electrode of the parts 14a and 14b. In this case, the position of each linear electrode of the electrode portions 13a and 13b coincides with the position of a linear electrode different from the corresponding linear electrode in the electrode portions 14a and 14b.

After obtaining the optimum position, the optical crystal plate is bonded at the optimum position. The optical crystal plate is bonded at a high temperature and a high pressure.

The electrode position adjustment method of the present embodiment described above has the following effects.

When the optical switch is viewed along the traveling direction of the incident light, the positions of the electrode portions 13a and 13b and the electrode portions 14a and 14b are the width direction of the linear electrode (this width direction is the longitudinal direction of the linear electrode). In the case of deviation in the intersecting direction (for example, the direction orthogonal to each other), part of the light transmitted between the linear electrodes of the electrode portions 13a and 13b is blocked by the electrode portions 14a and 14b. Accordingly, the output light intensity is reduced when the optical switch is turned on (voltage supply is stopped). For this reason, the extinction ratio of the optical switch is lowered.

On the other hand, according to the electrode position adjusting method of the present embodiment, the positions of the electrode portions 13a and 13b and the electrode portions 14a and 14b when the optical switch is viewed along the traveling direction of the incident light The width direction of the electrode can be surely and accurately matched. When the positions of the electrode portions 13a and 13b coincide with the positions of the electrode portions 14a and 14b, most of the light transmitted between the linear electrodes of the electrode portions 13a and 13b passes between the linear electrodes of the electrode portions 14a and 14b. To do. Therefore, the output light intensity of the optical switch is higher than the output light intensity of the optical switch having a deviation in the electrode position, and as a result, the extinction ratio can be improved.

Also, when adjusting the electrode position of the optical switch by visual observation, the adjustment accuracy varies depending on the person. For this reason, in the manufacturing process of the optical switch, variations occur in the adjustment accuracy of the electrode position, and it is difficult to provide an optical switch with stable quality.

On the other hand, according to the electrode position adjusting method of the present embodiment, the electrode position can be reliably adjusted to the optimum position, so that an optical switch with stable quality can be provided.

Note that the positions of the electrode portions 13a and 13b and the electrode portions 14a and 14b of the optical switch are shifted not only in the width direction of the linear electrodes but also in the length direction of the linear electrodes. However, the change in the output light intensity of the optical switch with respect to the displacement of the electrode position in the length direction of the linear electrode is sufficiently larger than the change in the output light intensity of the optical switch with respect to the displacement of the electrode position in the width direction of the linear electrode. small. Therefore, the extinction ratio is not greatly reduced by the displacement of the electrode position in the length direction of the linear electrode. In other words, in order to improve the extinction ratio, it is important to adjust the electrode to an optimal position in the width direction of the linear electrode.

In addition, since the optical switch formed using the electrode position adjusting method of the present embodiment has a configuration in which a plurality of refractive index change regions are formed in the traveling direction of incident light, in addition to the effect of electrode position adjustment described above. Thus, the extinction ratio can be further improved.

Further, each electrode portion of the optical switch is composed of a plurality of linear electrodes arranged at equal intervals and having a main cross section having a maximum area in the same plane. Since the electrode portion composed of such a plurality of linear electrodes has a smaller area and capacity than the plate electrode described in Patent Document 1, it is possible to save power and reduce the size of the optical switch.

(Second Embodiment)
FIG. 8 is a block diagram showing the configuration of a system for carrying out the electrode position adjusting method according to the second embodiment of the present invention. This electrode position adjustment system has the same configuration as the system shown in FIG. 4 except that a temperature control means including a plurality of temperature control elements 80 and a temperature control unit 23 which is a function of the control unit 20 is provided. It is. In FIG. 8, the same components as those shown in FIG.

The temperature control element 80 is a thermoelectric conversion element typified by a Peltier element, and is provided on a part (exposed surface) of each electrode portion 13a, 13b, 14a, 14b. In the example shown in FIG. 8, the temperature control element 80 is provided on the voltage supply terminal surface of the electrode portion. The temperature control element 80 has a heat generating surface, and the heat generating surface is formed so as to contact the voltage supply terminal surface.

The temperature control unit 23 controls current supply from a power source (not shown) to each temperature control element 80. When a current is supplied to the temperature control element 80, the temperature control element 80 generates heat. When the temperature control element 80 generates heat, the electrode portion is heated by the heat energy from the heat generating surface, and as a result, the temperature of the optical crystal around the electrode portion increases.

The amount of heat energy supplied from the heat generating surface of the temperature control element 80 to the electrode portions 13a, 13b, 14a, and 14b is determined by the amount of current supplied to the temperature control element 80. Further, parameters such as the thermal conductivity of the electrode portions 13a, 13b, 14a, and 14b and the distance from the temperature control element 80 to the region where the temperature should be maintained (electrode forming region including the electrode portions 13a, 13b, 14a, and 14b) Based on this, it is possible to calculate the amount of heat energy required to maintain the region where the temperature is to be maintained within a certain temperature range. The temperature control unit 23 controls the current supply to the temperature control element 80 so that the calculated amount of heat energy is supplied from the temperature control element 80 to the electrode units 13a, 13b, 14a, and 14b. Thereby, the temperature of the electrode formation area containing electrode part 13a, 13b, 14a, 14b is maintained in a fixed temperature range.

All of the optical crystal plates 10 to 12 are transparent above the phase transition temperature at which the crystal structure changes, and are electro-optical crystals capable of obtaining a large refractive index near the phase transition temperature, such as KTN (potassium niobate tantalate: KTa). _1-x Nb _x O ₃ ).

FIG. 9 is a flowchart showing one procedure of the electrode position adjusting method according to the second embodiment of the present invention using the position adjusting system of FIG.

Referring to FIG. 9, first, the stage control unit 22 receives an operator input through the input unit 70 and moves the stages 50 and 51 in accordance with the input instruction. By this movement control, a position between the electrodes (initial position) that serves as a guide is set (step S20).

Next, the temperature control unit 23 supplies the temperature control elements 80 to the temperature control elements 80 so that the temperature of the optical crystal plates 10 to 12 (particularly the temperature of the electrode formation region) is maintained at or above the phase transition temperature. Current supply is controlled (step S21).

Next, the optimum position determination unit 21 moves the stage 51 from the initial position state in the first direction by a predetermined amount, and obtains a first waveform indicating the level change of the received signal from the light receiving unit 30 at that time. (Step S22). Further, the optimum position determination unit 21 moves the stage 51 from the initial position state in the second direction by a predetermined amount, and acquires a second waveform indicating the level change of the received signal from the light receiving unit 30 at that time. (Step S23).

Finally, the optimum position determination unit 21 examines the highest point in the acquired first and second waveforms, and the linear electrodes of the electrode portions 13a and 13b and the linear shapes of the electrode portions 14a and 14b at that point. The position with the electrode is determined as the optimum position (step S24).

After obtaining the optimum position, the optical crystal plate is bonded at the optimum position. The optical crystal plate is bonded at a high temperature and a high pressure.

According to the electrode position adjusting method of this embodiment, in an optical switch in which an optical crystal plate is formed of an electro-optic crystal that is transparent at a phase transition temperature or higher, the temperature of the electro-optic crystal (more preferably, the electrode formation region) is changed to a phase transition. Maintain above the temperature and near the phase transition temperature. That is, the electro-optic crystal (more desirably, the electrode formation region) is maintained in a transparent state. By maintaining the electro-optic crystal (more desirably, the electrode formation region) in a transparent state, the amount of light transmitted through the electrode formation region is increased, and the output waveform (the first waveform) of the light receiving unit 30 associated with the movement of the stage is correspondingly increased. The change in the first and second waveforms is increased. As a result, the peak of the output waveform (first and second waveforms) can be detected with higher accuracy.

In the electrode position adjusting method of the present embodiment, a method (temperature control means) for maintaining at least the electrode formation regions formed on the optical crystal plates 10 to 12 at a temperature equal to or higher than the phase transition temperature through the temperature control element 80. However, other methods (other temperature control means) may be used instead. For example, the optical crystal plates 10 to 12 are accommodated in a casing capable of maintaining the temperature of the internal atmosphere at the instructed temperature, and the temperature control unit 23 controls the temperature in the casing. In the housing, the atmosphere is heated, thereby increasing the temperature of the optical crystal plates 10-12. The internal temperature is set such that the optical crystal plates 10 to 12 are maintained at a temperature equal to or higher than the phase transition temperature.

In addition, when the electro-optic crystal (more desirably, the electrode formation region) is maintained at a temperature equal to or higher than the phase transition temperature, the upper limit of the temperature control range is determined by considering the temperature dependence of the refractive index of the electro-optic crystal. Within the operating range of the switch. Specifically, the upper limit of the temperature control range is determined as follows.

When the temperature of the electro-optic crystal rises, the refractive index of the electro-optic crystal changes, and accordingly, the critical angle when incident light is totally reflected at the refractive index interface in the refractive index changing region also changes. For this reason, for example, when the incident angle of the incident light with respect to the refractive index interface is set to a critical angle at the phase transition temperature, the set incident angle becomes smaller than the critical angle when the critical angle changes due to the temperature rise. In this case, incident light is not totally reflected at the refractive index interface of the refractive index change region, but is transmitted through the refractive index change region, and as a result, the optical switch does not operate. Therefore, the upper limit of the temperature control range is a temperature at which the critical angle does not exceed the set incident angle. The temperature condition where the critical angle does not exceed the set incident angle can be defined by the parameters of the distance between the linear electrodes, the magnitude of the applied voltage, and the incident angle.

The electrode position adjusting method of the present embodiment described above has the same effects as the electrode position adjusting method of the first embodiment described above.

It is desirable that the above-described electrode position adjustment methods of the first and second embodiments be executed in a state close to the actual optical switch setting state.

Below, the setting state of the optical switch and a system arrangement example optimal for the setting state will be described in detail.

(First arrangement example)
10A and 10B are schematic views showing a first arrangement example when the electrode position adjusting method of the present invention is executed. FIG. 10A schematically shows a partial cross section taken along line BB of the optical switch shown in FIG. 1A. FIG. 10B schematically shows a partial cross section taken along line AA of the optical switch shown in FIG. 1A.

The optical crystal plates 10 to 12 are made of an electro-optical crystal (for example, KTN), and the refractive index n is about 2.2. In this electro-optic crystal, the refractive index change Δn when a voltage of 5 V is applied between the linear electrodes (when an electric field is applied) is −0.022. The thicknesses of the optical crystal plates 10 to 12 are 100 μm, 34 μm, and 100 μm, respectively.

The wavelength λ of incident light is 460 nm. The diameter D _b of the incident light is 20 [mu] m. The spacing _Sx between the linear electrodes of the electrode portions 13a, 13b, 14a, and 14b is 5 μm. The width E _w of each linear electrode is 5 μm. The electrode portions 13a, 13b, 14a, and 14b all have a thickness of 500 nm. The distance between the electrode portion 13b and the end of the optical crystal plate 11 in the Y-axis direction is 50 μm. The Y-axis direction is the longitudinal direction of the linear electrode.

Under the above optical switch conditions, the light utilization efficiency is high and the thickness of the optical crystal plate 11 as the intermediate layer can be made the thinnest is as follows.

The critical angle θ _m when the incident light is totally reflected at the refractive index interface of the refractive index changing region of the electro-optic crystal whose refractive index changes by applying an electric field is 81.9 °, and the electrode portions 13a, 13b, 14a, 14b electrode length E _l of linear electrodes is 141 .mu.m. The electrode length E _l may be greater than 141 .mu.m.

The first-order diffraction angle θ _d is 2.4 °. First stage of the electrode portion 13a and the second stage of the electrode portion 14a of the Y-axis direction of the spacing S _y and the Z-axis direction between S _z respectively 95 .mu.m, is 34 .mu.m. Here, the Z-axis direction is the thickness direction of the optical crystal plate. The optical path length L ₁ of the transmitted light between these electrode portions 13a and 14a is 239 μm. The electrode portions 13b and 14b have the same relationship as the electrode portions 13a and 14a.

When adjusting the electrode position of the optical switch set as described above, the light from the light irradiation unit 60 is incident on the incident end face of the optical crystal plate 10 at an incident angle of 18.2 °. Here, the incident end face of the optical crystal plate 10 is a surface perpendicular to the interface between the optical crystal plates 10 and 11 (formation surface of the electrode portions 13a and 13b) or the interface between the optical crystal plates 11 and 12 ( electrode portions 14a and 14b). This is a surface perpendicular to the formation surface. The incident position of the light from the light irradiation unit 60 on the incident end face of the optical crystal plate 10 is set to a position of 115 μm from the interface between the optical crystal plates 11 and 12. The light receiving unit 30 is disposed at a position where light transmitted through the optical crystal plates 10 to 12 among the light from the light irradiation unit 60 can be received.

The system shown in FIG. 1 or FIG. 4 is set so as to satisfy the above arrangement conditions, and the optimum position is obtained by the electrode adjustment method in the first or second embodiment described above.

(Second arrangement example)
FIG. 11A and FIG. 11B are schematic views showing a second arrangement example when the electrode position adjusting method of the present invention is executed. FIG. 11A schematically shows a partial cross section taken along line BB of the optical switch shown in FIG. 1A. FIG. 11B schematically shows a partial cross section taken along line AA of the optical switch shown in FIG. 1A.

The optical crystal plates 10 to 12 are made of an electro-optical crystal (for example, lithium niobate (LN)), and the refractive index n is about 2.286. The electro-optic crystal has a refractive index change Δn of −0.016 when a voltage of 100 V is applied between the linear electrodes (when an electric field is applied). The thicknesses of the optical crystal plates 10 to 12 are 100 μm, 29 μm, and 100 μm, respectively.

The wavelength λ of incident light is 460 nm. The diameter Db of incident light is 20 μm. The spacing _Sx between the linear electrodes of the electrode portions 13a, 13b, 14a, and 14b is 5 μm. The width E _w of each linear electrode is 1 μm. The electrode portions 13a, 13b, 14a, and 14b all have a thickness of 500 nm.

Under the above optical switch conditions, the light utilization efficiency is high and the thickness of the optical crystal plate 11 as the intermediate layer can be made the thinnest is as follows.

The critical angle θ _m when the incident light is totally reflected at the refractive index interface of the refractive index changing region of the electro-optic crystal whose refractive index changes by applying an electric field is 83.2 °, and the electrode portions 13a, 13b, 14a, 14b electrode length E _l of linear electrodes is 169 .mu.m. The electrode length E _l may be greater than 169 .mu.m.

The first-order diffraction angle θ _d is 2.3 °. The distance S _{y in} the Y-axis direction and the distance S _{z in the} Z-axis direction between the first-stage electrode portion 13a and the second-stage electrode portion 14a are 77 μm and 29 μm, respectively. Here, the Y-axis direction is the longitudinal direction of the linear electrode, and the Z-axis direction is the thickness direction of the optical crystal plate. The optical path length L _l of the transmitted light between these electrode portions 13a and 14a is 248 μm. The electrode portions 13b and 14b have the same relationship as the electrode portions 13a and 14a.

When adjusting the electrode position of the optical switch set as described above, the light from the light irradiation unit 60 is incident on the incident end face of the optical crystal plate 10 at an incident angle of 15.7 °. Here, the incident end face of the optical crystal plate 10 is a surface perpendicular to the interface between the optical crystal plates 10 and 11 (formation surface of the electrode portions 13a and 13b) or the interface between the optical crystal plates 11 and 12 ( electrode portions 14a and 14b). This is a surface perpendicular to the formation surface. Further, the incident position of the light from the light irradiation unit 60 on the incident end face of the optical crystal plate 10 is set at a position of 99 μm from the interface between the optical crystal plates 11 and 12. The light receiving unit 30 is disposed at a position where light transmitted through the optical crystal plates 10 to 12 among the light from the light irradiation unit 60 can be received.

The system shown in FIG. 1 or FIG. 4 is set so as to satisfy the above arrangement conditions, and the optimum position is obtained by the electrode adjustment method in the first or second embodiment described above.

In the first and second embodiments described above, one of the stages 50 and 51 is configured to move by a predetermined amount in the first direction and in the second direction opposite to the first direction. However, the present invention is not limited to this. The stage to be moved may be either one or both of the stages 50 and 51. That is, at least one of the stages 50 and 51 is moved in a direction crossing the longitudinal direction of the linear electrodes, and light is received while changing the relative positions of the linear electrodes between the optical crystals 11 and 12. Monitor the output level. Thereby, accurate adjustment of an electrode position is possible. In addition, it is desirable that the range in which the relative position of the linear electrodes between the optical crystals 11 and 12 is changed is the range of the interval between the linear electrodes.

[Electrode formation method]
Next, the electrode forming method of the optical switch will be specifically described.

FIGS. 12A to 12I are cross-sectional process diagrams showing one procedure of an electrode forming method for an optical switch.

First, a resist 91 is applied to the surface of the electro-optic crystal 90 (step of FIG. 12A). Next, using the mask 92 on which the electrode pattern is formed, the surface on which the resist 91 is applied is masked, and the applied surface is exposed (step of FIG. 12B). Next, the exposed portion of the resist 91 is removed (step of FIG. 12C).

Next, the exposed surface of the electro-optic crystal 90 is etched using the resist 91 from which the exposed portion has been removed as a mask (step of FIG. 12D). The etching material is hydrogen fluoride or the like.

Next, an electrode material (gold, platinum, etc.) is deposited on the etched portion of the electro-optic crystal 90 to form an electrode 93 (step in FIG. 12E), and then the resist 91 is removed (step in FIG. 12F). . Next, these surfaces are polished so that the surface of the electro-optic crystal 90 and the surface of the electrode 93 have the same height (step of FIG. 12G).

Next, the surface of the electro-optic crystal 90 on which the electrode 93 is formed and the surface of the electro-optic crystal 95 on which the electrode 96 is similarly formed in the steps of FIGS. 12A to 12G are moved in the moving direction. After adjusting the crystal position while moving along, the electro-optic crystals 90 and 95 are bonded together by being adhered under high temperature and high pressure conditions (step of FIG. 12H). In this bonding step, the surfaces to which the electro-optic crystals 90 and 95 are bonded are processed into surfaces having sufficient flatness.

Finally, the surface of the electro-optic crystal 95 on which the electrode 96 is formed and one surface of the electro-optic crystal 97 are brought into close contact under high temperature and high pressure conditions, thereby bonding the electro-optic crystals 95 and 97 (see FIG. Step 12I). In this bonding step, the surfaces to which the electro-optic crystals 95 and 97 are bonded are processed into surfaces having sufficient flatness.

By applying the processes of FIGS. 12A to 12I described above, the electrode portions 13a, 13b, 14a and 14b are formed on the optical crystal plates 11 and 12 shown in FIG. 1A, and the optical crystal plates 10 to 12 are bonded. It can be performed.

The optical switch created by using the electrode position adjusting method of the present invention can be applied to an optical communication device, an image display device, an image forming device, and the like. Hereinafter, an image display apparatus and an image forming apparatus will be described as application examples of the optical switch.

[Image display device]
Next, the configuration of an image display apparatus including an optical switch created using the electrode position adjusting method of the present invention will be described.

FIG. 13 is a schematic diagram showing an example of an image display device. This image display device includes laser light sources 102, 103, 104, collimator lenses 105, 106, 107, reflection mirror 108, dichroic mirrors 109, 110, horizontal scanning mirror 115, vertical scanning mirror 116, and optical switches 118, 119, 120. Has a housing 100 containing the. The optical switches 118, 119, and 120 are optical switches created by using the electrode position adjusting method of the present invention.

A collimator lens 105, an optical switch 118, and a reflection mirror 108 are sequentially arranged in the traveling direction of the laser light from the laser light source 102. A parallel light beam from the collimator lens 105 enters the optical switch 118. The optical switch 118 operates according to a control signal supplied from a control unit (not shown). During a period in which the control signal is on (voltage supply period), a voltage is applied to the electrode portion of the optical switch 118 to form a refractive index change region, so that incident light is reflected in the refractive index change region. This reflected light deviates from the optical path toward the reflecting mirror 108. During a period when the control signal is off (voltage supply stop period), incident light passes through the optical switch 118 and travels toward the reflection mirror 108.

The collimator lens 106, the optical switch 119, and the dichroic mirror 109 are sequentially arranged in the traveling direction of the laser light from the laser light source 103. A parallel light beam from the collimator lens 106 enters the optical switch 119. In the optical switch 119, the same operation as that of the optical switch 118 is performed. During the period when the control signal is on (voltage supply period), incident light is reflected in the refractive index change region, and the reflected light deviates from the optical path toward the dichroic mirror 109. During a period when the control signal is off (voltage supply stop period), incident light passes through the optical switch 119 and travels toward the dichroic mirror 109.

The collimator lens 107, the optical switch 120, and the dichroic mirror 110 are sequentially arranged in the traveling direction of the laser light from the laser light source 104. A parallel light beam from the collimator lens 107 enters the optical switch 120. In the optical switch 120, the same operation as that of the optical switch 118 is performed. During a period in which the control signal is on (voltage supply period), incident light is reflected in the refractive index change region, and the reflected light deviates from the optical path toward the dichroic mirror 110. During a period in which the control signal is off (voltage supply stop period), incident light passes through the optical switch 120 and travels toward the dichroic mirror 110.

The dichroic mirror 109 is provided at a position where the light beam from the optical switch 119 and the light beam reflected by the reflection mirror 108 intersect. The dichroic mirror 109 has a wavelength selection characteristic that reflects light from the optical switch 119 and transmits light from the reflection mirror 108.

The dichroic mirror 110 is provided at a position where the light beam from the optical switch 120 and the light beam from the dichroic mirror 109 intersect. The dichroic mirror 109 has a wavelength selection characteristic that reflects light from the optical switch 120 and transmits light from the dichroic mirror 109.

The horizontal scanning mirror 115 is arranged in the traveling direction of the light beam from the dichroic mirror 110, and its operation is controlled by a horizontal scanning control signal from a control unit (not shown). The vertical scanning mirror 116 is disposed in the traveling direction of the light beam from the horizontal scanning mirror 115, and its operation is controlled by a vertical scanning control signal from a control unit (not shown).

As the laser light sources 102, 103, and 104, light sources that emit laser light of colors corresponding to the three primary colors R, G, and B are used. A color image can be displayed on the screen 117 by controlling on / off of the optical switches 118, 119, and 120 and controlling the horizontal scanning mirror 115 and the vertical scanning mirror 116.

[Image forming apparatus]
Next, the configuration of an image forming apparatus including an optical switch created using the electrode position adjusting method of the present invention will be described.

FIG. 14 is a schematic diagram illustrating an example of an image forming apparatus. This image forming apparatus includes a housing 200, an fθ lens 223, and a photoreceptor 224. A laser light source 202, a collimator lens 205, a reflection mirror 208, a scanning mirror 222, and an optical switch 218 are accommodated in the housing 200. The optical switch 218 is an optical switch created using the electrode position adjusting method of the present invention.

A collimator lens 205, an optical switch 218, and a reflection mirror 208 are sequentially arranged in the traveling direction of the laser light from the laser light source 202. A parallel light beam from the collimator lens 205 enters the optical switch 218. The optical switch 218 operates in accordance with a control signal supplied from a control unit (not shown). During a period in which the control signal is on (voltage supply period), a voltage is applied to the electrode portion of the optical switch 218 to form a refractive index change region, so that incident light is reflected in the refractive index change region. This reflected light deviates from the optical path toward the reflecting mirror 208. During a period when the control signal is off (voltage supply stop period), incident light passes through the optical switch 218 and travels toward the reflection mirror 208.

The scanning mirror 222 is arranged in the traveling direction of the light beam from the reflection mirror 208, and its operation is controlled by a scanning control signal from a control unit (not shown). Light from the scanning mirror 222 is applied to the photoconductor 224 via the fθ lens 223.

By turning on / off the optical switch 218 and controlling the scanning mirror 222, an image can be formed on the photosensitive member 224.

The electrode position adjustment methods and systems of the first and second embodiments described above are examples of the present invention, and the procedure and configuration thereof can be changed as appropriate without departing from the spirit of the invention.

In the first and second embodiments, the example in which the electrode position is adjusted for the two optical crystal plates each having a plurality of linear electrodes is described. However, the present invention is limited to this. It is not a thing. The present invention can also be applied to those in which a plurality of linear electrodes are formed on each of three or more optical crystal plates. Specifically, by repeating the procedure of adjusting the electrode position for two optical crystal plates, and then adjusting the electrode position by stacking another optical crystal on the adjusted optical crystal plate. The electrode positions of the plurality of optical crystal plates can be adjusted.

According to the present invention, the first optical crystal side linear electrode and the second optical crystal side linear electrode when the first and second optical crystals are viewed along the traveling direction of the light flux. The position can be surely and accurately matched in the width direction of the linear electrode. Therefore, in the optical switch using the first and second optical crystals at the optimum position, if light is incident from the same direction as the light beam at the time of electrode position adjustment, it follows the traveling direction of the incident light When the optical switch is viewed, the positions of the linear electrode on the first optical crystal side and the linear electrode on the second optical crystal side are exactly the same in the width direction of the linear electrode. In this case, since most of the light transmitted between the linear electrodes on the first optical crystal side passes between the linear electrodes on the second optical crystal side, the output light intensity of the optical switch can be further increased. As a result, the extinction ratio can be improved.

Further, according to the present invention, the electrode portion of the optical switch is composed of a plurality of linear electrodes arranged at equal intervals. Since the electrode portion composed of such a plurality of linear electrodes has a smaller area and capacity than the plate electrode described in Patent Document 1, it is possible to save power and reduce the size of the optical switch.

The present invention has been described above with reference to the embodiments, but the present invention is not limited to the above-described embodiments. Various modifications that can be understood by those skilled in the art can be made to the configuration and operation of the present invention without departing from the spirit of the present invention.

This application claims priority based on Japanese Patent Application No. 2008-86615 filed on Mar. 28, 2008, the entire disclosure of which is incorporated herein.

Claims (14)

1. First and second optical crystals each having a surface on which a plurality of linear electrodes are formed at equal intervals are stacked so that the longitudinal directions of the plurality of linear electrodes coincide with each other. Irradiating a region including the plurality of linear electrodes formed on the optical crystal 2 with a light beam;
   In a state in which the first and second optical crystals are stacked, at least one of the first and second optical crystals is moved in a direction intersecting the longitudinal direction, and the first and second optical crystals are Detecting the intensity of transmitted light that has passed through the first and second optical crystals while changing the relative position of the plurality of linear electrodes between each other,
   An electrode position adjustment method in which the detected moving position where the intensity of the transmitted light is the highest is the optimum position of the first and second optical crystals.
2. The range in which the relative position of each of the plurality of linear electrodes between the first and second optical crystals is changed as the range of the interval between the plurality of linear electrodes. The electrode position adjusting method as described in 2.
3. When moving one of the first and second optical crystals, along the direction intersecting the longitudinal direction, the first and second directions are opposite to each other in the first direction and the second direction, respectively. 3. The electrode position adjusting method according to claim 1, wherein one of the second optical crystals is moved by a movement amount that is a half of an interval between the plurality of linear electrodes. 4.
4. Irradiation of the light beam is performed in a state where at least a region including the plurality of linear electrodes formed in the first and second optical crystals is maintained at a temperature equal to or higher than a phase transition temperature at which the structure of the optical crystal changes. The electrode position adjusting method according to any one of claims 1 to 3.
5. The electrode position adjusting method according to claim 4, wherein the plurality of linear electrodes are heated to maintain a region including the linear electrodes at a temperature equal to or higher than the phase transition temperature.
6. The atmosphere in a housing containing the first and second optical crystals is heated to maintain the first and second optical crystals at a temperature equal to or higher than the phase transition temperature. Electrode position adjustment method.
7. The incident angle of the light beam on the surface on which the plurality of linear electrodes are formed at equal intervals constitutes the first and second optical crystals when a voltage is applied between the plurality of linear electrodes. 7. The incident angle according to any one of claims 1 to 6, which is an incident angle that satisfies a condition when incident light is totally reflected by a refractive index interface of a refractive index changing region formed in an electro-optic crystal. The electrode position adjusting method as described.
8. First and second optical crystals each having a surface in which a plurality of linear electrodes are formed at equal intervals are respectively held in a stacked state so that the longitudinal directions of the plurality of linear electrodes coincide with each other. And a second stage,
   A light irradiating unit that irradiates a light beam onto a region including the plurality of linear electrodes formed on the first and second optical crystals held on the first and second stages;
   A light receiving portion for detecting transmitted light that has passed through the first and second optical crystals;
   Relative positions of the plurality of linear electrodes between the first and second optical crystals by moving at least one of the first and second stages in a direction crossing the longitudinal direction A control unit that monitors the output level of the light receiving unit while changing
   The control unit determines the moving position where the output level of the light receiving unit is the highest as the optimum position of the first and second optical crystals.
9. The said control part makes the range which changes the relative position of the said some linear electrode between the said 1st and 2nd optical crystals as the range of the space | interval of these linear electrodes. The electrode position adjusting system according to claim 8.
10. The control unit moves one of the first and second stages along the direction intersecting the longitudinal direction to the first direction and the second direction opposite to the first direction. The electrode position adjustment system according to claim 8 or 9, wherein the electrode position adjustment system is moved by a movement amount that is a half of an interval between the electrodes.
11. The apparatus further comprises temperature control means for maintaining at least a region including the plurality of linear electrodes formed in the first and second optical crystals at a temperature equal to or higher than a phase transition temperature at which the structure of the optical crystal changes. The electrode position adjusting system according to any one of items 8 to 10 of the range.
12. The electrode position adjustment system according to claim 11, wherein the temperature control means includes a temperature control element for heating the plurality of linear electrodes.
13. 12. The electrode position adjustment system according to claim 11, wherein the temperature control means is means for heating an atmosphere in a housing containing the first and second optical crystals.
14. The incident angle of the parallel light flux on the surface on which the plurality of linear electrodes are formed at equal intervals constitutes the first and second optical crystals when a voltage is applied between the plurality of linear electrodes. 14. The incident angle according to any one of claims 8 to 13, which is an incident angle that satisfies a condition when incident light is totally reflected by a refractive index interface of a refractive index changing region formed in an electro-optic crystal. The electrode position adjustment system described in 1.

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