WO2004038712A1

WO2004038712A1 - Phase adjusting liquid crystal device, optical pickup and optical recording/reproducing device

Info

Publication number: WO2004038712A1
Application number: PCT/JP2003/013643
Authority: WO
Inventors: Koichiro Kishima
Original assignee: Sony Corporation
Priority date: 2002-10-24
Filing date: 2003-10-24
Publication date: 2004-05-06
Also published as: JP2004145985A

Abstract

A phase adjusting liquid crystal device which intends to stabilize the optical characteristics and electric resistance of a transparent conductive film, which is used in an optical recording/reproducing device that records or reproduces data to be recorded or recorded on a recording medium by condensing a laser beam onto a recording medium, and which can adjust the position distribution of a condensed laser beam by allowing a laser beam to pass through a liquid crystal device that can partially adjust the refractive index of a liquid crystal material, wherein a conductive material for applying voltage to a liquid crystal material consists of materials (2, 6) mainly containing a tin oxide material.

Description

Specification

Phase adjustment liquid crystal device, optical pickup and optical recording / reproducing device

The present invention relates to a phase adjustment liquid crystal device used as an aberration correction device in an optical recording / reproducing apparatus capable of optically recording and / or reproducing data. Background technology,

In a conventional liquid crystal device, ITO (IndiomTinOxide) was used for a transparent conductive film as in a liquid crystal display. In a liquid crystal display, the shortest wavelength range of a color filter that determines the illumination wavelength may be about 46 O nm, and the wavelength characteristics of ITO materials near 400 nm are not considered a problem. Was.

Patent Document 1

Unexamined Japanese Patent Publication No. Hei 3 — 166 5 18

However, the light source of an optical recording / reproducing apparatus capable of optically recording and / or reproducing data has a shorter wavelength for increasing the recording density, and emits light having a wavelength of around 400 nm. System materials are also being adopted.

For this reason, no problem occurred even if ITO was used as the conductive film in the wavelength range of the color filter, but the absorptance of the ITO material could vary at wavelengths around 400 nm. Because of the large number, the transmittance of the liquid crystal device was consequently inconsistent by more than 10%. In a liquid crystal device, in which the voltage applied to the liquid crystal material can be partially changed, it is desirable that the transparent conductive material has a high resistance value because the power consumption is reduced. . However, since the ITO material has been developed for the purpose of lowering the electrical resistance value of the long wiring portion in the liquid crystal display, a high-resistance transparent conductive film is formed using the ITo material. There was an inconvenience that it was difficult to form.

When a high-frequency voltage waveform is applied instead of a DC voltage as the voltage applied to the liquid crystal device, the input between the voltage supply side and the voltage receiving device side (the liquid crystal device in the present invention) is performed. Although impedance matching is required, variations in the resistance value of the transparent conductive thin film, which is low, make impedance matching difficult and complicate the measurement of the voltage supply circuit. Was.

Therefore, in order to form a high-resistance film using an ITO material, there is a method of reducing the film thickness. However, if the film thickness is reduced, the film becomes an island-shaped film and the resistance value is stabilized. Becomes difficult. Moreover,

Since it is not easy to stabilize the absorptance of the ITO material at a wavelength of 400 nm, the variation in the optical characteristics of the liquid crystal device is increased. An optically high absorptivity not only wastes the laser beam but also raises the temperature of the liquid crystal device, causing a problem in the operating characteristics of the liquid crystal device. There is a disadvantage that the possibility increases

The fact that ITO materials have low resistance in the first place

According to the above, there is a disadvantage of complicating impedance matching when a high-frequency voltage waveform is used as the driving voltage of the device. Therefore, the present invention has been made in view of such a point. Optical properties and electrical resistance of i-type film can be stabilized It is an object to provide a phase adjustment liquid crystal device.

The phase adjustment liquid crystal device of the present invention is used for an optical recording / reproducing apparatus for recording or reproducing data recorded on a recording medium by focusing a laser beam on the recording medium. Phase adjustment liquid crystal device that adjusts the phase distribution of the condensed laser light by transmitting the laser light to a liquid crystal device that can partially adjust the refractive index of the laser In the above, the conductive material for applying a voltage to the liquid crystal material is made of a material mainly composed of a tin oxide material.

Therefore, according to the present invention, the following operations are performed.

The phase adjusting liquid crystal device of the present invention has a high transmittance to a laser beam of a wavelength of 400 nm for recording and reproducing data on and from a recording medium. Variation in absorption rate can be suppressed.

Further, in the optical pickup of the present invention, since the resistance value of the transparent conductive film is high, even when a high-frequency voltage waveform is applied instead of a DC voltage as a voltage applied to the liquid crystal device, the optical pickup is provided with a voltage supply side. Since the impedance matching with the device receiving the voltage (the liquid crystal device in the present invention) can be set to a high impedance state, the design of the voltage supply circuit can be facilitated.

An optical pickup according to the present invention is used for an optical recording / reproducing apparatus that records or reproduces data recorded on a recording medium by focusing a laser beam on the recording medium. Phase adjustment liquid crystal device that adjusts the phase distribution of the condensed laser light by transmitting the laser light through a liquid crystal device that can partially adjust the refractive index of the laser In the optical pickup having the above, the conductive material for applying a voltage to the liquid crystal material is made of a material mainly composed of a tin oxide material. Therefore, according to the present invention, the following operations are performed.

The optical pickup of the present invention has a high transmittance to a laser beam having a wavelength of 400 nm for recording and reproducing data on and from a recording medium. Variation in rate can be suppressed.

Further, in the optical pickup of the present invention, since the resistance value of the transparent conductive film is high, the voltage applied to the liquid crystal device is not a DC voltage. Since the impedance matching with the receiving device side (the liquid crystal device according to the present invention) can be performed in a state of no impedance or impedance, the design of the voltage supply circuit can be facilitated.

The optical recording / reproducing apparatus of the present invention records or reproduces data recorded on a recording medium by focusing a laser beam on the recording medium, and measures the refractive index of a liquid crystal material. Optical recording using a phase-adjusting liquid crystal device that adjusts the phase distribution of the laser light condensed by transmitting the laser light to a liquid crystal device that can be partially adjusted In the regenerating apparatus, the conductive material for applying the liquid pressure to the liquid / liquid material is a material mainly composed of a tin oxide material.

The optical recording / reproducing apparatus of the present invention has a high transmittance to a laser beam having a wavelength of 400 nm for recording / reproducing data on / from a recording medium, so that the absorptance can be reduced. The variability of the absorption rate can be suppressed.

Further, in the optical recording / reproducing apparatus of the present invention, since the transparent conductive film has a high resistance value, a voltage is supplied even when a high-frequency voltage waveform is applied instead of a DC voltage as a voltage applied to the liquid crystal device. And the device side receiving the voltage (the liquid crystal device in the present invention). Since the impedance matching can be set to the high impedance state, the design of the voltage supply circuit can be facilitated. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a diagram showing a method for forming a transparent conductive material of a device applied to the present embodiment. FIG. 1A shows a vacuum deposition method, and FIG. 1B shows a sputtering V-method.

FIG. 2 is a diagram showing a method of manufacturing a liquid crystal device applied to the embodiment a.

FIG. 3 is a diagram showing a method of manufacturing a liquid crystal device applied to the present embodiment.

FIG. 4 is a diagram showing a method of manufacturing a liquid crystal device applied to the present embodiment.

FIG. 5 is a diagram showing a method of manufacturing a liquid crystal device applied to the present embodiment.

FIG. 6 is a diagram showing a method of manufacturing a liquid crystal device applied to the present embodiment.

FIG. 7 is a diagram showing a method of manufacturing a depiice, which is called “Suidan B” applied to the present embodiment.

FIG. 8 is a diagram illustrating a method of manufacturing a liquid crystal device applied to the present embodiment.

FIG. 9 is a diagram illustrating a principle of aberration correction using a liquid crystal device applied to the present embodiment. BEST MODE FOR CARRYING OUT THE INVENTION

Embodiments of the present invention will be described below with reference to the drawings as appropriate.

The phase adjustment liquid crystal device of the present invention is In the manufacturing method, the thin conductive film made of ITO is made of a transparent conductive material containing tin oxide as a main component and not containing indium oxide (IZO). In the following embodiments, a method of manufacturing a transparent conductive thin film containing tin oxide as a main component will be described because the optical characteristics of the thin film and the electrical resistance of the thin film are stabilized.

First, a case where a method for producing a transparent conductive thin film by a vacuum evaporation method is used will be described.

As shown in FIG. 1A, in the process of forming a transparent electrode (S2, S4 described later), when a transparent conductive thin film containing tin oxide as a main component is formed by a vacuum evaporation method, A pellet 2 made of 100% tin oxide material is used as the source, and irradiated with an electron beam (Electronic Beam) 3 in a vacuum to form the tin oxide material. It can be heated to vapor to adhere to the glass substrate 1 as a sample.

Here, as a measure to prevent the oxygen inside the thin film from being released, it is desirable to introduce oxygen 4 into the vacuum chamber 15.

Next, a case in which a method for producing a transparent conductive thin film by a sputtering method is used will be described.

As shown in FIG. 1B, the process of forming the transparent electrode (S2, S

In 4), in the case of using the packs-ring is argon gas constant concentration - and retaining clips rows scan Nono ⁰ jitter-rings used by introducing oxygen gas mixture 8 positive ions due to the mixed gas 8 Can do

Compared with the vapor deposition method, the state of oxygen elimination inside the thin film can be controlled with relatively high accuracy.

However, in the case of 100% tin oxide, it is not possible to produce a high-density material, so it is not possible to form a target material. Not easy.

For this reason, a target that can withstand the sputtering process is produced by using a pellet material 6 of a mixture of tin oxide and antimony oxide (Sb 2 O 3) in a concentration of several percent with tin oxide as a main component. Then, a thin film containing tin oxide as a main component is vapor-deposited on the glass substrate 1 to form a transparent conductive thin film by a sputtering process.

At this time, the inventor of the present invention used a target material in which 3% of antimony oxide (Sb203) was mixed with tin oxide (Sn02), and the oxygen partial pressure was 10%. A thin film containing tin oxide as a main component was able to be produced by forming a film in a mixed gas of argon and oxygen.

The method of manufacturing the above liquid crystal device will be described with reference to FIGS.

In FIG. 2, first, in step S1, non-reflective coating 11 on glass substrate 1 is performed.

In step S2, a transparent electrode forming step (first surface) using ITOl2 is performed.

Here, ITO (Indium Tin Oxide) material 12 is used as a transparent electrode material. At this time, when the vacuum evaporation method is used, oxygen is introduced as described above. For example, when the sputtering method is used as the formation method, during the sputtering process, the ITO thin film is formed so as to contain water so as to be in an amorphous state by containing moisture, and then the dedicated film is formed. It intends rows by Rinono ⁰ turning to Uetsu door etching using an etching solution (wetetching) of.

In step S3, a patterning step (first surface) of the ITO electrode 13 positive and negative with respect to ITOl2 is performed.

In step S4, a step of forming a transparent electrode using ITO 14 (second Face).

In step S5, a patterning step (second surface) of the ITO electrode 15 positive and negative with respect to the ITO14 is performed.

During this step, it is necessary to protect the transparent electrode material on the first surface.

In step S6, a firing process (first and second surfaces) of the ITO electrode material is performed.

In order to make the electrical characteristics of both surfaces of the substrate uniform, it is desirable to perform the firing process of the transparent electrodes on the first and second surfaces simultaneously. For example, when the ITO material is formed in an amorphous state, it is necessary to perform a heat treatment in order to optically reduce the absorption of the ITO film and stabilize the electric conductivity. The conditions for the heat treatment are generally about 350 ° C. for about 30 minutes in an air atmosphere.

In step S *, a groove 16 is formed on the first surface of the glass substrate 1 by an etching process.

Here, the groove 16 is formed along the end face of the ITO electrode 13. Here, the etching is performed by, for example, an ion milling / FIB (F (Futan)) IonBeamRIE (RecactiveIonEtChing) process.

In FIG. 3, in step S7, the alignment film 17 is formed (first surface).

In order to orient the liquid crystal material in a predetermined direction, it is necessary to have a structure having electrical or mechanical as well as magnetic anisotropy. In general, since it is easy to give anisotropy electrically, a highly polarizable film (alignment film 17) is formed. In the manufacturing method of the liquid crystal display, for example, flexographic printing is generally used for forming the alignment film 17 because the substrate is large, but when the size of the substrate is small, the spin coating method is also possible. It is. For example, when a polyimide-based material, which is common in liquid crystal displays, is used as the alignment film 17, it is necessary to form it by printing or spin-coating and then bake it. And since the baking process is based on the dehydration reaction, the baking process generally has a processing temperature of 200 ° C. or more. In some cases, a baking treatment at 220 ° C. is required after a drying treatment at 90 ° C.

In step S8, the alignment film 18 is formed (second surface). Here, among the heat treatment steps included in the baking step of the alignment films 17 and 18, there is a possibility that a high-temperature heat treatment step can be commonly used.

Perform alignment treatment (rubbing treatment) (first surface) in step S 9 o

For example, when an organic material such as a polyimide-based alignment film is used as the alignment film material, the orientation direction of the polymer material is generally random immediately after the film is formed. Have no nature. Therefore, as a treatment for generating electrical anisotropy, an orientation treatment for aligning the orientation direction is required. There are two general methods for the alignment treatment: a rubbing treatment using a rubbing cloth and a light alignment method using light.Currently, the manufacturing method for liquid crystal displays is rubbing. The rubbing method using cloth is generally used.

In step S10, an orientation process (rubbing process) (second surface) is performed.

In step S11, the step of forming the spacer mixed conductive adhesive 19 (first surface) is performed.

In order to apply a voltage to the liquid crystal material, the voltage must be supplied to the glass substrates on both sides of the portion where the liquid crystal material is sealed. In many types of liquid crystal devices, the ability to apply an external electrical signal to one substrate simplifies the structure. Therefore, a method is used in which the material constituting the wall for enclosing the liquid crystal material is made conductive to partially electrically connect the substrates on both sides sandwiching the liquid crystal material. A specific method of making the electrical connection is to adopt conductive particles having a diameter slightly larger than the diameter of the spacer that defines the distance between the glass substrates. When the distance defined by the formula (1) is reached, the conductive particles are crushed by the glass substrate, and an electrical connection is obtained. Note that the spacer is formed of a hard material such as glass, and the conductive particles are formed of a soft material such as a plastic material having a gold plating.

In step S12, the preliminary firing process of the spacer mixed conductive adhesive is performed.

(Side 1).

When bonding the glass substrates, air must not come out from the inside of the adhesive due to surface bonding, so the bubbles inside the adhesive must be removed before full curing. It is desirable that the solvent be removed in addition to the solvent. If the screen printing method is used as the adhesive forming method, bubbles inside the application medium are often removed when the adhesive passes through the screen mesh. First, the solvent inside the adhesive is removed by a heat treatment at a temperature at which the curing agent of the adhesive does not react.

Here, the steps of the glass substrate facing the liquid crystal material on the first surface side of the glass substrate 1 will be described.

In FIG. 4, in step S 1 _ 1, the glass substrate (2-1) 2

Apply anti-reflection coating 21 to 1. This is done in step S above.

The contents are the same as in step 1.

In step S1-2, a transparent electrode of ITO 22 is formed. O When a high-precision electrode pattern is to be formed on the glass substrate (2-1) 2-1 on the power glass side, the steps S2, -y In the case where high pattern accuracy is not required (0.1 mm degree), it is necessary to carry out the same process as in step S3, for example, using a method such as shadow sputtering. In step S1-3, firing of the ITO electrode material is performed.

This step has the same contents as the step S6. In step S14, formation of an alignment film 23 is performed.

This step has the same contents as the steps S7 and S8 described above.

In step S115, an alignment process (rubbing process) is performed. This step is the process and contents of step S9 and step S10 described above.

In step S1-16, perform substrate splitting process (scribing process is possible) o

In order to make the board size suitable for the bonding process,

(b a r) shape. Here, as for the method of dividing the substrate, if accuracy can be obtained, a dividing method using a scribing process can be applied, and a dicing method can also be applied.

In FIG. 5, in step S13, a bonding step (first surface) of a glass substrate is performed.

If the temperature applied in step S7 and step S9 of forming the alignment film is high, the step for forming the alignment film on both sides must be performed in the process of step S13. In S 13, the alignment film on the second surface is pressed against the press jig 24 o

,

The glass substrates are bonded with the adhesive formed in the process. It is desirable that the bonding condition of the glass substrate is centered on the instruction condition of the adhesive. In step S14, the step of forming the spacer mixed conductive adhesive 25 (second surface) is performed.

In step S15, a preliminary firing step (second surface) of the spacer mixed conductive adhesive is performed.

Here, the steps of the glass substrate facing the liquid crystal material on the second surface side of the glass substrate 1 will be described.

In FIG. 6, the anti-reflection coating 31 is applied to the glass substrate (2-2) 212 in step S2-1. This is the same as the above-described step S 1.

In step S2-2, a transparent electrode is formed by IT032. When forming a high-precision electrode pattern on the glass substrate (2_2) 2-2 on the cover glass side, the same steps as those in Steps S2 and S3 described above need to be performed. If not required (approximately 0.1 mm), puttering can be performed by, for example, shadow sputtering.

In step S2-3, firing of the ITO electrode material is performed.

This step is the same as the step S6 described above. In step S2-14, an alignment film 33 is formed.

This step has the same contents as the steps S7 and S8 described above.

In step S2'5, an alignment process (rubbing process) is performed. This step has the same contents as the steps S9 and S10 described above.

In step S2-16, perform the substrate dividing process (scribing process is possible) o

In order to make the substrate size suitable for the bonding process,

Process into (ar) shape. Here, the method of dividing the board is not accurate. If possible, a division method using scribing can be applied, and a dicing method can also be applied.

In FIG. 7, in step S16, a glass substrate bonding step (second surface) is performed.

In step S17, division into Bar-shaped sizes is performed.

In this step, it is not easy to use a scribing process because there is no space for arranging diamonds, so a dicing step had to be used. It is possible to perform division by destruction starting from the groove formed by the method.

In order to fill the glass substrate with the liquid crystal material, the substrate is divided so that the liquid crystal injection port is at the end. In this step, both the dividing method using scribing and the dicing method can be applied.However, when dividing using the dicing step, pure water or A cleaning process is required after the division, because there is a high risk of dicing blade powder and the like entering the space where the liquid crystal material is to be injected.

In step S18, a vacuuming step is performed.

In order to fill the liquid crystal material 35, the container 36 in which the liquid crystal material 35 is immersed is evacuated 36. In addition, it is desirable to perform a beta (bake) step for drying in advance to increase the degree of vacuum. The ultimate vacuum may be about the same as a roughing vacuum pump such as a rotary pump.

In step S19, the liquid crystal material is filled.

With the vacuum maintained, the liquid crystal injection port of the sample is positioned so as to touch the liquid crystal material, and then nitrogen N 2 is introduced into the vacuum container 內 as indicated by 37. Then, the liquid crystal material is filled by returning the pressure to the atmospheric pressure. Here, the reason for introducing nitrogen N 2 is the storage stability of the liquid crystal material. It is to increase.

In step S20, the liquid crystal material 38 corresponding to the injection port of the liquid crystal element is extruded.

A load is externally applied to a portion of the liquid crystal element where the liquid crystal material 38 is filled, and the liquid crystal material 38 corresponding to the volume of the liquid crystal material 38 of the liquid crystal element filled in the injection port is discharged from the injection port. It will be extruded

In step S 21, the liquid crystal material 38 and U V (U 1 t r a V i o

1 et r ay s) Replace with curing adhesive 3 9

The liquid crystal material 38 extruded in the step S20 is wiped off, and a UV curing adhesive 39 for sealing the liquid crystal material 38 is applied to the wiped portion. Then, by releasing the applied load, the UV curing adhesive 39 is filled in the liquid crystal material injection port of the liquid crystal element.

In step S22, a UV irradiation step is performed.

The UV light 40 is irradiated to cure the UV curing adhesive 39 filled in the step S21. Here, since the liquid crystal material 38 is not sufficiently light-resistant to UV light 40, the liquid crystal material 38

The UV light 40 is irradiated from the injection P side so that the V light 40 is not irradiated.o Therefore, the selection of the UV-curable adhesive 39 depends on the reactivity of the liquid 38 In addition to selecting a low one, it is necessary to use a high transmittance of UV light 40.

In step S23, a dividing step for each cell is performed.

Although not shown, a liquid crystal device connected in a par (bar) shape is divided into small sizes suitable for a use form. The dividing method used here is a method using a scribing process because two glass substrates (2-11) and a glass substrate (.2-2-2) are laminated on the glass substrate 1. , It is easy to cause dimensional error Therefore, a dicing process is desirable. Since the liquid crystal injection port is already closed, there is no fear that cutting fluid will enter the injection port.

Next, the operating principle and usage of a liquid crystal device for spherical aberration correction using a liquid crystal device manufactured by the above-described liquid crystal device manufacturing method will be described. FIG. 9 is a diagram illustrating the operation principle of aberration correction using a liquid crystal device.

Figure 9 shows the operating principle of a phase modulation device (including a spherical aberration capture device) that uses the change in refractive index by applying a voltage to the liquid crystal material. In this case, by arranging the optically uniaxial liquid crystal material in the liquid crystal device 51 so as to be linearly aligned, the light polarization plane is not changed, and the light traveling direction is also changed. Without the light phase can be modulated.

That is, in the liquid crystal device 51, the phase and the traveling direction 56 of the incident light are uniform by generating the region 58 of the change in the refractive index and the region 59 of the change in the refractive index of the liquid crystal device 51. However, as shown in 57, the phase of the transmitted light can change in the same traveling direction. Therefore, this phase modulation device is an effective phase modulation device for light having a polarization component in the direction defined by the alignment film of the liquid crystal device 51.

In order to apply as a spherical aberration correction device to an optical disc device, the liquid crystal must be changed so as to generate a phase change that cancels the spherical aberration caused by the difference in cover thickness due to the difference in the recording / reproducing layer of the optical disc. The voltages VS (52) and VL (53) need to be applied to the liquid crystal material of the device 51. Low resistance conductive film 55-1, 55-2 for applying a predetermined voltage distribution by voltage VS (52) and VL (53) to the liquid crystal material of liquid crystal device 51, high resistance conductive It is desirable that the pattern electrode of the film 54 be fixed to incident light. Therefore, the spherical aberration correction device is used for aperture and objective lens. Position in the X and y directions is fixed relative to the

In a system that performs track servo using a two-axis actuator, it is desirable that the liquid crystal device be mounted on a two-axis actuator.o

Further, as described above, the phase modulation device is a phase modulation device effective for light having a polarization component in a direction defined by the alignment film of the liquid crystal device 51, and therefore, the circularly polarized light is used. In an optical disk system that performs recording and reproduction with an optical system,

Say 1 Z with tenos

It is desirable that the four-wavelength plate is also mounted on the two-axis actuator.

For example, an optical disk system (blueray) having a laser beam having a wavelength of 405 nm as a light source and having a cano with a thickness of about 0.1 mm using a NA (Uumer 1 ca 1 Aerture) 0 • 85 objective lens. In the case of), a thin film having a power-per-layer structure is required to achieve a short wavelength and a high NA, but the tolerance for the spherical aberration is not wide in order to increase the number of recording layers. Therefore, by introducing a spherical aberration correction device that uses the change in the refractive index caused by applying a voltage to the liquid crystal material, the tolerance for the spherical aberration of the light incident on the optical disk is reduced, and the multilayer ROM ( R ead Only Memory) Can play discs.

Further, as shown in the above-described present embodiment, the inventor of the present invention prototyped a liquid crystal device having two liquid crystal surfaces, and made light incident on an optical disk having a phase change recording film and reflection from the optical disk. The method that captures both spherical aberrations of light shows that the spherical aberration technology using liquid crystal devices can be applied to recordable media.

It is to be noted that the present invention is not limited to the above-described embodiment, and may adopt other configurations as appropriate without departing from the scope of the claims of the present invention. Nor.

Further, the phase adjusting liquid crystal device of the present invention is used for an optical recording / reproducing apparatus which records or reproduces data recorded on a recording medium by focusing a laser beam on the recording medium. A phase adjustment liquid crystal that adjusts the phase distribution of the focused laser light by transmitting the laser light to a liquid crystal device that can partially adjust the refractive index of the material. In the device, the conductive material for applying a voltage to the liquid crystal material is made of a material containing tin oxide as a main component, so that the optical absorptance of the transparent conductive film can be reduced and the transparent conductive film can be made transparent. This makes it possible to increase the resistance of the conductive film, so that even when a high-frequency voltage waveform is applied instead of a DC voltage as the voltage applied to the liquid crystal device, the voltage is supplied to the side that supplies the voltage. Voltage Since wear matching I impedance of the device side (the liquid crystal device according to the present invention) which receives in the state of high impedance, an effect that it is possible to facilitate the design of the voltage supply circuit.

Further, in the phase adjustment liquid crystal device of the present invention, the conductive material for applying a voltage to the liquid crystal material is a material containing tin oxide material as a main component and antimony oxide added thereto. This has the effect of being able to form a conductive thin film that is transparent at a given value.

Further, in the phase adjusting liquid crystal device of the present invention, since the wavelength of the laser light is 450 nm or less in the above description, the transparency to the laser light of the wavelength of 400 nm for recording / reproducing data is improved. The effect is high because the absorption rate of the laser beam can be reduced due to the high absorption rate, and the variation in the absorption rate can be suppressed. Industrial potential INDUSTRIAL APPLICABILITY The present invention is applicable to a phase adjustment liquid crystal device used as an aberration correction device in an optical recording / reproducing apparatus capable of optically recording or reproducing data.

Claims

The scope of the claims

1. An optical recording / reproducing device that records or reproduces data recorded on a recording medium by focusing laser light on the recording medium. In a phase adjustment liquid crystal device that adjusts the phase distribution of condensed laser light by transmitting laser light to a liquid crystal device that can be adjusted

A phase-adjusting liquid crystal device, characterized in that a conductive material for applying a voltage to the liquid crystal material is made of a material mainly composed of a tin oxide material.

2. The phase-adjusting liquid crystal according to claim 1, wherein the conductive material for applying a voltage to the liquid crystal material is a material containing a tin oxide material as a main component and an antimony oxide added thereto. device.

3. The phase-adjusting liquid crystal device according to claim 1, wherein the wavelength of the laser beam is 450 nm or less.

4. An optical recording / reproducing apparatus that records or reproduces data recorded on a recording medium by focusing laser light on the recording medium. Optical pickup having a phase adjustment liquid crystal device that adjusts the phase distribution of the condensed laser light by transmitting the laser light through a liquid crystal device that can be adjusted At

An optical pickup characterized in that a conductive material for applying a voltage to a liquid crystal material is made of a material mainly composed of a tin oxide material.

5. The optical pickup according to claim 4, wherein the conductive material for applying a voltage to the liquid crystal material is a material containing a tin oxide material as a main component and an antimony oxide added thereto.

6. The optical pickup according to any one of claims 4 and 5, wherein a wavelength of the laser light is 45 nm or less.

7. Recording or playback of the data recorded on the The laser beam is transmitted through a liquid crystal device that can partially adjust the refractive index of the liquid crystal material by condensing the laser light on a recording medium. Thus, in an optical recording / reproducing apparatus using a phase adjustment liquid crystal device that adjusts the phase distribution of a focused laser beam,

An optical recording / reproducing apparatus, wherein a conductive material for applying a voltage to a liquid crystal material is made of a material mainly composed of a tin oxide material.

8. The optical recording / reproducing apparatus according to claim 1, wherein the conductive material for applying a voltage to the liquid crystal material is a material containing a tin oxide material as a main component and an antimony oxide added thereto. apparatus.

9. The optical recording / reproducing apparatus according to claim 1, wherein the wavelength of the laser beam is 450 nm or less.