JP2000242956A - Optical head and information reproducing device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a highly reliable optical head capable of executing recording, reproducing, etc., at the recording density higher than the recording density determined by the diffraction threshold and suppressing the heat generation of an evanescent light generating means and the deformation, etc., accompanying the same and an information reproducing device using the same. SOLUTION: This optical head has the constitution obtained by providing the circumference of a micro-opening 104a for generating evanescent light from the light introduced by an optical path 102 for introducing the light from a light source 101 to a prescribed position with a cooling member 120. As a result, the evanescent light generating means which rises to a high temperature by irradiation with the light may be cooled and, therefore, the excessive heating of the evanescent light generating means does not occur any more and the reliability of the optical head may be improved. In addition, the reliability of the information recording device mounted with such optical head may be improved as well.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical head for optically recording, erasing or reproducing information by irradiating an information recording medium with light, and an information reproducing apparatus using the same.
The present invention relates to an optical head capable of recording, erasing, or reproducing at high density by using evanescent light, and an information reproducing apparatus using the same.

[0002]

2. Description of the Related Art A conventional technique will be described below.

[0003] In general, the recording density on a recording medium is determined by the diameter of a condensed spot, but with a conventional optical head, the diameter of the condensed spot cannot be made smaller than the diffraction limit determined by the numerical aperture of the objective lens and the wavelength of the light source. Therefore, a recording density higher than the diffraction limit could not be obtained.

[0004] Therefore, in order to form a light spot below the diffraction limit and dramatically improve the recording density of a recording medium,
For example, Applied. Physics. Letter (Appl.Phys.Le
tt.), 61.142 (1992), the tip of an optical fiber is sharpened, and a minute aperture having a diameter equal to or less than the wavelength is provided at the tip, and recording on a recording medium is performed using evanescent light generated in the opening. -A technology for performing regeneration is disclosed.

[0005]

However, according to the conventional method of generating evanescent light by providing a minute aperture at the tip of an optical fiber, light is transmitted to the minute aperture provided by sharpening the tip of the optical fiber. Concentration and the temperature of the minute opening becomes very high. For this reason, disadvantages such as expansion and deformation of the minute opening due to the heat generated therein and deformation of the recording medium provided in the vicinity occur, and the optical head and the information reproducing apparatus using the same. There is a problem that the reliability of the device is lowered.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of the prior art, and can perform recording / reproducing at a recording density higher than the recording density determined by the conventional diffraction limit. It is an object of the present invention to provide a highly reliable optical head capable of suppressing heat generation and accompanying deformation thereof, and an information reproducing apparatus using the same.

[0007]

According to the present invention, a cooling member is provided around evanescent light generating means for generating evanescent light from light guided by an optical system for guiding light from a light source to a predetermined position. Have.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 is a light source, an optical system for guiding light from the light source to a predetermined position, and an evanescent light for generating evanescent light from the light guided by the optical system. Light generating means, holding means for holding the evanescent light generating means, driving means for moving the holding means to a predetermined position on a recording medium, and light generated by interaction between the evanescent light and the recording surface of the recording medium. An optical head provided with light receiving means for receiving the light, wherein the cooling member is provided in the vicinity of the evanescent light generating means, whereby the evanescent light generating means, which becomes high in temperature by light irradiation, can be cooled. .

According to a second aspect of the present invention, the cooling member is constituted by at least one of a protrusion, a heat pipe, a heat wiring, and a Peltier element, so that heat around the evanescent light generating means can be diffused more quickly. Can be.

According to a third aspect of the present invention, there is provided a light source, an optical system for guiding light from the light source to a predetermined position, and evanescent light generating means for generating evanescent light from the light guided by the optical system. Holding means for holding the evanescent light generating means, driving means for moving the holding means to a predetermined position on a recording medium, and receiving light generated by interaction between the evanescent light and the recording surface of the recording medium. An optical head comprising: a light receiving unit that emits light, and a cooling member provided around the evanescent light generating unit, wherein the evanescent light is applied to the cooling member by applying a flow of a fluid generated with the rotation of the recording medium. By cooling the light generating means, the cooling efficiency can be greatly improved with a simple configuration.

According to a fourth aspect of the present invention, the cooling member is formed to be longer in the direction and shorter in the direction perpendicular to the direction with respect to the direction in which the fluid generated by the rotation of the recording medium flows. Thereby, better cooling characteristics can be realized while reducing the fluid resistance.

According to a fifth aspect of the present invention, the cooling means has at least one position that is substantially parallel to the direction in which the fluid generated by the rotation of the recording medium flows. Variation in the force received from the flow of the fluid can be suppressed.

According to a sixth aspect of the present invention, there is provided a light source, an optical system for guiding light from the light source to a predetermined position, and evanescent light generating means for generating evanescent light from the light guided by the optical system. Holding means for holding the evanescent light generating means, driving means for moving the holding means to a predetermined position on a recording medium, and receiving light generated by interaction between the evanescent light and the recording surface of the recording medium. And a surface roughness of the medium facing surface of the evanescent light generating means of 1 nm or more and 25 nm or less, so that the spacing between the optical head and the recording medium is appropriately secured, and the evanescent light is emitted. It is possible to increase the surface area of the evanescent light generating means, which is high in temperature while generating satisfactorily, so that its cooling efficiency is further improved In addition, since the surface roughness is formed to be 1 nm or more, it is possible to reduce the possibility that the evanescent light generating means directly facing the recording medium will cause adsorption when it comes into contact with the recording medium. Thus, it is possible to prevent a situation in which the optical head and the recording medium are stuck and become inoperable. Further, by setting the surface roughness to 25 nm or less, it is possible to minimize the generation of dust from the evanescent light generating means during operation, which is caused by the increased roughness.

According to a seventh aspect of the present invention, the surface roughness increases as it approaches the light-emitting portion of the evanescent light generating means, so that the surface roughness is adjusted according to the heat distribution in the evanescent light generating means when light is incident. Since the magnitude of the margin can be determined, the evanescent light generating means can be cooled very efficiently.

The invention according to claim 8 is characterized in that the surface roughness is different between the vicinity of the light emitting portion of the evanescent light generating means and the other part, so that the vicinity of the minute opening which becomes particularly high in the evanescent light generating means. Can be further increased, so that the cooling efficiency around the minute opening can be further improved.

According to the ninth aspect of the present invention, since the holding means is constituted by the slider, the distance between the recording medium and the evanescent light generating means can be easily controlled, and the information reproduction characteristics can be stabilized. Can be done.

According to a tenth aspect of the present invention, a light shielding means is formed on a medium facing surface of a slider made of a light transmitting member,
By forming a minute opening in the light-shielding means and forming the light-emitting part of the evanescent light generating means, evanescent light can be generated with a simple configuration, so that the configuration of the optical head can be simplified.

According to an eleventh aspect of the present invention, the surface roughness near the minute opening is 0.05 d with respect to the thickness (d) of the light shielding means.
By setting the distance to 0.5d or less, the spacing between the optical head and the recording medium can be reduced, the occurrence of adsorption between the optical head and the recording medium can be suppressed, and the cooling efficiency of the evanescent light generating means can be reduced. And the generation of dust can be suppressed.

According to a twelfth aspect of the present invention, in the optical head according to any one of the first to ninth aspects, the recording medium being rotated by a medium driving unit that holds and drives the recording medium. By irradiating evanescent light and reproducing information, an information reproducing apparatus having stable reproduction characteristics can be obtained.

According to the thirteenth aspect of the present invention, it is possible to prevent the temperature around the minute opening from becoming excessively high by irradiating the light to the evanescent light generating means after confirming the state of the recording medium, thereby improving the reliability. And an information reproducing apparatus having a stable information reproducing characteristic.

(Embodiment 1) Next, an optical head and an information reproducing apparatus according to Embodiment 1 will be described.

FIG. 1 is a diagram showing an information reproducing apparatus according to an embodiment of the present invention.

In FIG. 1, reference numeral 101 denotes a light source;
As 1, it is preferable to use a laser or a light emitting diode having a relatively large light amount. In particular, a device made of a semiconductor is small in size and low in price, so that it is suitable for use in an information reproducing device having a small volume.

Reference numeral 102 denotes an optical path. The optical path 102 is composed of a waveguide such as an optical fiber, an optical system using a lens or the like, and has a function of guiding light emitted from the light source 101 to a predetermined position. are doing.

Reference numeral 103 denotes a slider. The slider 103 is partially or entirely formed of a light-transmitting material. The slider 103 floats or slides on the recording medium 106 to record at a predetermined position on the recording medium 106. It has a function of moving light used for reproduction, and light guided through the optical path 102 is configured to be incident on the slider 103.

Reference numeral 104 denotes a light blocking means.
The slider 103 is provided on a surface of the slider 103 facing the recording medium 106, and a small opening 104 a having a diameter smaller than the wavelength of light emitted from the light source 101 is formed in a part of the slider 103. A slider 103 from a light source 101 via an optical path 102
Enters a small aperture 104a formed in the light shielding means 104 and takes the form of an evanescent wave. Normal,
The light wave cannot pass through the small opening 104a smaller than the wavelength, but if the distance between the small opening 104a and the recording medium 106 is sufficiently small (up to 100 nm), evanescent light is generated from the small opening 104a to generate the recording medium. 106 can interact with it. Therefore, it is very important to accurately detect and control the distance between the minute opening 104a and the recording medium 106. Slider 10
The configuration of 3 and the light blocking means 104 will be described later in detail.

Reference numeral 105 denotes a support member. One end 105 a of the support member 105 is
Is connected to the end face on the opposite side to the face on which is provided, and the other end 105b is connected to the driving means 107. The operation of the driving means 107 is such that the evanescent light, which is transmitted to the slider 103 via the support member 105 and is generated at the minute opening 104 a provided on the medium facing surface of the slider 103, is moved to a predetermined position on the recording medium 106. , Information recording and / or reproduction. Here, as the driving unit 107, a unit that rotates around an axis such as a voice coil motor or a unit that linearly moves in the XY directions such as an actuator can be used.

Reference numeral 108 denotes a light-condensing member.
It is provided on the opposite side of the slider 103 with the recording medium 106 interposed therebetween, and functions to condense a part of the propagating light generated by the evanescent light generated in the minute opening 104 a interacting with the recording surface 106 a of the recording medium 106. have.

Reference numeral 109 denotes a light receiving member.
It has a function of receiving the reproduction light corresponding to the information on the recording surface 106a condensed by the condensing means 108 and converting it into an electric signal.

Reference numeral 111 denotes a medium driving unit, and the medium driving unit 1
Reference numeral 11 includes a medium holding unit and a medium driving unit, and has a function of holding and rotating the recording medium 106. As the medium holding unit, a known mechanism for holding a medium using a nail, a ball, or the like can be used. In addition, it is preferable to use a spindle motor using a fluid bearing as the medium drive unit, because silence can be improved and a long life can be achieved.

Reference numeral 120 denotes a cooling member provided around the small opening 104a. The cooling member 120 lowers the temperature around the small opening 104a, which becomes high in temperature, and accompanies a change in the opening diameter of the small opening 104a and expansion and contraction of the periphery. It has a function of minimizing a change in recording / reproducing characteristics. This cooling member 1
20 will be described in detail later.

Next, recording on the phase change type recording medium 106 will be described.

Light emitted from the light source 101 at a predetermined output enters the slider 103 via the optical path 102, and the light shielding means 10 formed on the medium facing surface of the slider 103.
Evanescent light is generated in the vicinity of the fourth small opening 104a. This evanescent light is converted into a phase change type recording medium 106.
At a predetermined position on the recording medium 106. In the portion of the recording medium 106 that has been heated by light irradiation to a temperature equal to or higher than the melting point, the portion that was in a crystalline state is temporarily melted and changes to an amorphous state in the course of a rapid temperature drop. Information is recorded based on the change between the crystalline state and the amorphous state.

Next, reproduction of information on the phase change recording medium 106 will be described. Since the amorphous portion and the crystalline portion of the recording medium 106 have different structures even if they have the same composition, they have different optical constants. Therefore, the minute opening 104
Even if the distance between a and the recording medium 106 is constant, the optical coupling efficiency between the minute opening 104a and the recording medium 106 changes between the amorphous state and the crystalline state. The intensity of light transmitted through the recording medium 106 changes according to the change in the optical coupling efficiency. That is, propagating light generated by the interaction between the evanescent light generated in the minute aperture 104a by the light emitted from the light source 101 and the recording medium 106 passes through the recording medium 106, passes through the light collecting member 108, and is transmitted to the light receiving member 109. The intensity of the incident light is different between the crystalline state and the amorphous state. Therefore, the information recorded on the recording medium 106 can be reproduced by detecting the difference in the intensity with the light receiving member 109.

Although the light source 101 and the optical path 102 are provided separately from the slider 103 in the present embodiment, the light source 101 and the optical path 102 may be provided on the slider 103. Further, a light source 101 and an optical path 102 are provided in
03 may be linked. By providing the light source 101 and the optical path 102 in the slider 103, the support means 105, and the driving means 107 in this manner, light from the light source 101 can be surely incident on a predetermined position of the moving slider 103, so that information Reproduction is reliable, the seek time can be shortened, and a mechanism for causing the light source 101 and the optical path 102 to follow the operation of the slider 103 can be simplified, so that productivity is high. An optical head having high reliability can be obtained.

Next, a detailed configuration of the slider and the light shielding means in the present embodiment will be described with reference to the drawings. FIG. 2 is a diagram showing a configuration of the slider according to the first embodiment of the present invention.

In FIG. 2, rail surfaces 103a, 103b, and 103c are formed on the medium facing surface side of the slider 103, and a light shielding means 104 is formed on the rail surface 103b.

The slider 103 has a function of moving the optical head on the recording medium 106 smoothly. As the type of the slider 103, a sliding type used in contact with the recording medium 106 or a floating type used while flying above the recording medium 106 may be used. Further, among the floating types, a contact start / stop method for starting and stopping the apparatus while the slider is in contact with the recording medium 106, a self-loading type floating head slider mechanism for starting and stopping without contact, a slider lifting and lowering Mold loading / unloading mechanism,
There is a non-contact type such as a ramp load type load / unload mechanism.

Further, it is preferable that the height of the rail surface of the slider is different depending on whether the light shielding means 104 is provided or not. When the slider 103 is of a sliding type or a CSS type, a rail provided with the light shielding means 104 is provided to prevent the light shielding means 104 from being damaged due to the contact between the light shielding means 104 and the recording medium 106. The surface 103b is preferably lower than the other rail surfaces 103a, 103c, and the medium facing surface of the light shielding means 104 is preferably lower than the other rail surfaces 103a, 103c.

In the case of the floating type, in which the start and stop are performed in a non-contact manner, the medium facing surface of the light shielding means 104 is formed higher than the other rail surfaces 103a and 103c. Since the distance (flying height) between the small aperture 106a and the minute opening 104a formed in the light shielding means 104 can be made smaller, the recording medium 1 is not affected by external vibration or the like.
Since evanescent light can more reliably come into contact with the recording medium 106 even if the light-shielding means 104 is slightly separated from the light-shielding means 104, extremely stable recording or reproduction characteristics can be realized, which is preferable.

The surface of the slider 103 is
The fact that light from the slider 103 is shielded by the light blocking means 104 having light absorption characteristics and reflection characteristics at a portion other than the portion where the light is incident and the small opening 104a is light irrelevant to recording and reproduction (stray light) leaked from the slider 103. This is preferable because it is possible to prevent the S / N ratio from deteriorating due to entering the light receiving member 109 as noise.

The light shielding means 104 has a minute opening 104a, an intermediate layer 104b and a light shielding layer 104c, and the minute opening 104a generates evanescent light as described above. On the other hand, the intermediate layer 104b and the light shielding layer 104c
The micro aperture 104a has a function of blocking light other than light contributing to generating evanescent light and suppressing generation of light (stray light) leaking toward the recording medium 106.

Here, the light-shielding layer 104c has an absorption property,
It has the function of absorbing incident light and converting it into heat. Therefore, the light shielding layer 104c is
High thermal conductivity and heat release are required to prevent the destruction of the material. Further, the size of the minute opening 104a changes due to thermal stress strain generated due to a temperature difference or a difference in thermal expansion coefficient between the intermediate layer 104b and the intermediate layer 104b.
In order to prevent the light-shielding layer 104c from being destroyed, it is necessary to pay attention to thermal expansion and the like.

Further, the intermediate layer 104b has a minute opening 104a.
Is provided between the light-shielding layer 104c where the light is concentrated and the temperature is high and the slider 103 which is a relatively low temperature to absorb the temperature difference and the difference of the expansion coefficient between the light-shielding layer 104c and the slider 103, It has a function of alleviating the stress caused by heat and suppressing the occurrence of inconveniences such as a change in the shape of the minute opening 104a and the destruction of the light shielding layer 104c.

Therefore, when the characteristic values of the intermediate layer 104b, the light shielding layer 104c, and the slider 103 are compared and examined, it is preferable that the characteristic values are set as follows.

First, the thermal conductivity (rate) is determined by the minute opening 104a.
Light is concentrated in order to define
c is the highest, adjacent to the light shielding layer 104c,
4a and the intermediate layer 104b in contact with the light-shielding layer 104c and the slider 103 in contact with the intermediate layer 104b become lower in this order, so that the generated heat can be efficiently dissipated.
This is preferable because the occurrence of inconveniences such as deformation and melting of the light shielding means 104 due to heat can be suppressed. In addition, by using a material whose thermal conductivity increases with an increase in temperature, the heat dissipation of a portion where heat is generated can be improved with an increase in temperature. Breakage of the light shielding means 104 can be suppressed more efficiently, and a more reliable optical head can be obtained.

Next, it is preferable that the heat release into the atmosphere is also reduced in the order of the light-shielding film 104c, the intermediate layer 104b adjacent to the light-shielding film 104c, and the slider 103, which generate a large amount of heat. In particular, the heat release property of the light-shielding film 104c should be at least twice as large as that of the intermediate layer 104b and the slider 103, so that the temperature rise of the light-shielding film 104c can be suppressed. This is preferable because breakage can be greatly suppressed.

Finally, it is preferable that the thermal expansion properties (linear expansion coefficients) of both the light shielding means 104 and the slider 103 be small, and that the difference be small. Also, the intermediate layer 104
b corresponds to the linear expansion coefficient of the slider 103 and the light-shielding layer 1.
04c can be set during the linear expansion coefficient of the slider 10c.
3 and the difference in linear expansion coefficient between the intermediate layer 104b and the intermediate layer 10b.
Since the difference in the coefficient of linear expansion between 4b and the light-shielding layer 104c can be reduced, inconveniences such as cracks caused by the difference in the respective coefficients of expansion can be suppressed, which is a more preferable configuration. .

In particular, the size such as the opening diameter of the minute opening 104a defined by the light-shielding layer 104c slightly changes according to the expansion and contraction of the light-shielding layer 104c. Especially small aperture 1
In a state where the evanescent light is generated from the light-shielding layer 104a, if the minute opening 104a is reduced due to the expansion of the light-shielding layer 104c when the temperature of the light-shielding layer 104c becomes high, the reach of the generated evanescent light is also reduced. Since the length becomes short, it becomes difficult to form the evanescent light to such an extent that the evanescent light comes into contact with the recording medium 106, and it becomes impossible to perform recording or reproduction. Therefore, the light shielding layer 10
The range of the linear expansion coefficient to be satisfied by 4c
It is required that the change in the size of a is within a range in which information can be recorded and reproduced using evanescent light, and furthermore, when light is irradiated, in which the shape change of the light-shielding layer 104c becomes large, that is, the temperature of the light-shielding layer 104c becomes higher. The use of a material having a coefficient of variation within 20% when comparing the linear expansion coefficient in the state and the linear expansion coefficient in the non-irradiated state with the light-shielding layer 104c at a lower temperature is within the temperature state. This is preferable because a change in the shape change amount of the light-shielding layer 104c due to the above can be minimized.

The slider 10 which satisfies the above characteristics
3 and the following materials can be considered as the materials of the intermediate layer 104b and the light shielding layer 104c.

First, the slider 103 is formed of a material having a light-transmitting property such as resin or glass, and in particular, a material having a transmittance of 90% or more at the wavelength of the light from the light source 101 here. This is preferable because evanescent light can be generated without lowering the light emission. In particular, since glass has a large strength, by using it as a material for forming the slider 103 which may possibly come into contact with the recording medium 106, there is little possibility that the glass will be damaged even if it comes into contact with the recording medium 106 to some extent. This is preferable because a highly reliable slider can be realized. Also, among glass materials, in particular, it has sufficient strength, has a small coefficient of thermal expansion,
Quartz glass, which has almost no change in coefficient of thermal expansion from low to high temperatures, is the most suitable material.

Next, the intermediate layer 104b is located between the slider 103 and the light-shielding layer 104c, and is often formed mainly of a material such as glass, resin, or metal. It is often determined accordingly. For example, when the slider 103 is formed of a glass material and the light shielding layer 104c is formed of a metal material,
4b is made of a glass material or a metal material, so that the difference in the coefficient of thermal expansion can be suppressed to a minimum. Therefore, inconveniences such as cracks are generated between each of the slider 103 and the light shielding layer 104c and the intermediate layer 104b. Can be suppressed. As an optimal combination, when quartz glass is used for the slider 103, lead glass or Pyrex glass can efficiently absorb a difference in thermal expansion between the slider 103 and the light-shielding layer 104c particularly in a high-temperature state. It is preferred. The thickness of the intermediate layer 104b is preferably about 10 nm to 1000 nm, because the difference in thermal expansion between the slider 103 and the light shielding layer 104c can be efficiently absorbed. Also,
It is preferable that the intermediate layer 104b is also formed of a translucent material. By forming the intermediate layer 104b with a light-transmitting material, the position where evanescent light is generated can be near the interface between the intermediate layer 104b and the light-shielding layer 104c. Therefore, the distance from the evanescent light generating portion to the recording medium 106 can be made shorter than in the case where the light is generated on the lower surface of the slider 103, so that the distance control between the recording medium 106 and the slider 103 is more easily performed. It is preferable because it can be used.

Next, the light shielding layer 104c is mainly made of Au, Ag, A
Metal materials such as l and Cu, SIO ₂ and TiO ₂
In many cases, it is formed of a material having a property of reflecting light, such as a combination of dielectric materials such as, or a material having a property of absorbing light due to a combination of a Si layer and a Ti layer. When the film thickness is about 10 nm to 100 nm, light can be prevented from leaking from a portion other than the minute opening 104a, and the evanescent light generated in the minute opening 104a is applied to the surface of the light shielding layer 104c facing the recording medium 106. This is a preferable configuration because it can be more reliably projected toward the recording medium 106 side, and information can be recorded and / or reproduced with the projected evanescent light more reliably.

In this embodiment, since the intermediate layer 104b has a high light-transmitting property, the minute opening 104a is
04c. Intermediate layer 104
b has a light-shielding characteristic,
Is preferably formed so as to penetrate through the intermediate layer 104b and the light shielding layer 104c.

Further, the light-shielding means 104 has a two-layer structure of the intermediate layer 104b and the light-shielding layer 104c. However, the light-shielding means 104 may have a three-layer or more layer structure. Intermediate layer 104 using functionally graded material
b can be eliminated.

As described above, in the present embodiment, a part or the entirety of the slider 103 is formed of a translucent member, and the minute opening 104a for generating evanescent light is formed on the medium facing surface. With this configuration, the slider 103 itself can be used as a means for generating evanescent light. Therefore, compared with a case where evanescent light generating means such as a probe is provided separately, alignment with the slider can be performed. Can be eliminated, and the number of parts and assembly man-hours can be reduced.
An optical head with extremely high product accuracy and high productivity can be realized.

The whole or a part of the slider 103 is formed of a translucent member, so that strict positioning between the optical path 102 and the minute opening 104a,
Even if a hole for transmitting light is not provided in the small aperture 10,
Since the light can be guided to the slider 4a, the configuration of the optical head can be simplified.
The optical head can be installed anywhere as long as it is the medium facing surface, so that the degree of freedom in designing the optical head can be ensured.

Next, light for generating evanescent light is concentrated, and the minute opening 104a which is considered to be heated to a high temperature is formed.
Consider cooling around.

First, in the present embodiment, the recording medium 106
The vicinity of the minute opening 104a is efficiently cooled by the flow of the fluid generated by the rotation of. Therefore, the recording medium 1
Until 06 reaches a predetermined number of rotations, light is not allowed to enter the minute opening 104a. Here, it is preferable that the inside of the information reproducing apparatus described in this embodiment is in a sealed state, and the inside atmosphere is preferably filled with a fluid such as air. A gas is preferably used as the fluid to be sealed. Among them, it is preferable to use a gas containing a small amount of impurities such as dry air, an inert gas such as an Ar gas, and an N ₂ gas to prevent corrosion inside the apparatus. Is preferred.

In order to perform the cooling with the fluid more reliably, the control as shown in FIG. 11 is performed.

FIG. 11 shows a part of a control block diagram of the information reproducing apparatus in the first embodiment of the present invention. FIG.
1, the control means 121 monitors the amount of current supplied to the drive means 111 and detects the number of revolutions of the drive means such as a Hall element.
2, the number of rotations of the recording medium 106 is detected. Then, the detected rotation speed is compared with a predetermined value previously input to the memory unit 123, and only when the detected rotation speed is equal to or more than the predetermined value, the light source control unit 124
The control is performed to issue a command to operate 01. Accordingly, when the light is applied to the minute opening 104a, the recording medium 106 always operates at a predetermined rotation or more, so that the vicinity of the minute opening 104a can be reliably cooled by the flow of the fluid generated along with the rotation. it can. As a result, the temperature of the minute opening 104a becomes high,
Significantly reduce the possibility that the shape of the minute opening 104a greatly expands and contracts or melts to deform the shape, thereby changing the reach of the evanescent light and deteriorating the information reproducing characteristics of the reproducing apparatus. Therefore, a highly reliable information reproducing apparatus can be realized.

In this embodiment, light is not emitted from the light source 101 until a predetermined rotation speed is reached. However, a shielding member or the like is inserted in the optical path from the light source 101 to the minute opening 104a. It is good also as composition which inserts and removes it. Further, the driving means state detecting means may use an optical encoder or detect an elapsed time since power-on.

Further, the minute opening 104a is
Is formed as close as possible to the fluid outflow end. During operation, the distance between the slider 103 and the recording medium 106 is smaller at the fluid outflow end side than at the fluid inflow end side. Therefore, the flow velocity of the fluid flowing between the slider 103 and the recording medium 106 is higher on the fluid outflow end side than on the fluid inflow end side, and the density of the fluid is also higher. Therefore, by configuring the minute opening 104a closer to the fluid outflow end with respect to the slider 103, the cooling efficiency around the minute opening 104a can be improved, and the distance from the recording medium 106 becomes shorter. The density can be increased, and the recording medium 106 can be reliably irradiated with evanescent light.

The minute opening 104a is preferably formed near the center of the slider 103 relative to the direction of movement (width direction) with respect to the recording medium 106. This is because even at the same fluid outflow end, the flow velocity of the fluid is higher near the center than at the end, and the cooling efficiency is further increased. In the case where the slider 103 has a medium facing surface that is not flat but has a rail surface or the like, a similar effect can be obtained by forming a minute opening 104a near the center of a plurality of rail surfaces. .

Further, in the present embodiment, the minute opening 104
Since the cooling member 120 is provided to improve the cooling efficiency of a, it will be described below.

FIG. 3 is a sectional view of the cooling member according to the first embodiment of the present invention, FIG. 4 is a plan view of the cooling member according to the first embodiment of the present invention, and FIG. 5 is a cooling member according to the first embodiment of the present invention. FIG. 6 is a plan view of the cooling member according to the first embodiment of the present invention.

As shown in FIGS. 3 and 4, a cooling member 120 is formed on the surface of the light shielding layer 104c opposite to the intermediate layer 104b. In the first embodiment, the cooling member 120 is composed of a plurality of protrusions 120a formed of a metal material, and can increase a surface area that comes into contact with outside air,
The temperature around the heated minute opening 104a can be efficiently reduced.

Here, the projections 120a may be provided at regular intervals as shown on the right side of FIGS. 3 and 4, or may be formed at a higher density near the minute opening 104a as shown on the left side of FIGS. It may be formed (in other words, the surface area is increased). If the protrusions are formed at a high density near the minute openings 104a, the protrusions can be arranged in accordance with the temperature distribution around the minute openings 104a, so that the cooling around the minute openings 104a can be performed more efficiently. The temperature gradient generated in the light shielding means 104 can be minimized. Therefore, it is possible to greatly reduce the possibility that a crack occurs in the light shielding means 104 or the aperture diameter of the minute opening 104a largely changes due to the temperature gradient, and has stable recording / reproducing characteristics and extremely high reliability. It can be an optical head. The rail-shaped projections need not always be continuous, and may be arranged in an intermittent straight line.

The protrusion 120a is formed in a rail shape, is longer than the relative movement direction of the slider 103 and the recording medium 106 (hereinafter abbreviated as the first direction), and is perpendicular to the first direction. In the second direction. As a result, the flow of the fluid generated along with the rotation of the recording medium 106 flows along the protrusion 120a, so that the flow of the fluid is less likely to be disturbed by the cooling member 120. An optical head having flying characteristics can be realized.

Further, when the protrusions are linearly arranged as described above, the direction of the protrusions 120a and the flow of the fluid during the movement of the slider 103 from the innermost circumference to the outermost circumference of the recording medium 106 by the driving means 107. It is preferable to set the direction of the protrusion 120a such that there is at least one position where the direction is substantially parallel to the direction. With such a configuration, the difference in the position of the slider 103 on the recording medium 106 changes the magnitude of the force that the protrusion 120a receives from the flow of the fluid, and causes variations in the flying characteristics of the slider. Since the optical head can be effectively suppressed, it is possible to provide a highly reliable optical head having stable flying characteristics and little fluctuation in recording / reproducing characteristics. Here, the protrusion 120a formed in a rail shape is used.
Were formed substantially parallel to each other, but may be formed non-parallel in consideration of fluctuations in levitation characteristics, cooling efficiency, and the like.
The inclination direction of the protrusion 120a may be any direction.

The structure of the projections 120a may be arranged in a lattice as shown on the right side of FIG.
May be arranged in a zigzag pattern as shown on the left side of. FIG.
May be formed radially around the minute opening 104a as shown on the right side of FIG. Further, as shown on the left side of FIG. 6, the protrusion 120a may be formed only around the minute opening 104a where the possibility of high temperature is particularly high.

In this embodiment, the projection 120a of the cooling member 120 is provided on the light shielding means 104. However, instead of providing the cooling member 120, irregularities are formed on the light shielding means 104, so that the minute openings 104a are formed. The cooling efficiency of the periphery can be improved. The same effect can be obtained by forming irregularities in advance on the surface of the slider 103 where the minute openings 104a are formed.

Further, in this embodiment, the light-blocking means 104 is formed on the slider 103 having a light-transmitting property, and the minute opening 104a is formed in a part of the light-blocking means 104 to generate the evanescent light. For example, even in a configuration in which minute projections are formed at the tip of an optical fiber, various devices for cooling the evanescent light generating means described above are naturally applicable.

(Embodiment 2) Hereinafter, Embodiment 2 of the present invention will be described with reference to the drawings.

FIG. 7 is a diagram showing an information reproducing apparatus according to Embodiment 2 of the present invention.

In FIG. 7, reference numeral 201 denotes a light source.
As 1, it is preferable to use a laser or a light emitting diode having a relatively large light amount. In particular, a device made of a semiconductor is small in size and low in price, so that it is suitable for use in an information reproducing device having a small volume.

Reference numeral 202 denotes an optical path. In the present embodiment, the optical path 202 is constituted by an optical system using a lens 211, a reflection mirror 212 and the like, and converts light emitted from the light source 201 into convergent light by the lens 211. Convert to the reflection mirror 212
And has a function of guiding to a predetermined position via the.

Reference numeral 203 denotes a slider. The slider 203 is partially or entirely formed of a light-transmitting material, and floats or slides on the recording medium 206 to record at a predetermined position on the recording medium 206. And / or has the function of moving light used for reproduction. A lens surface 203a is formed on a surface of the slider 203, on the side opposite to the medium facing surface, on which the light guided from the optical path 202 is incident, and condenses the incident light at a predetermined position. In the present embodiment, the lens surface 203a is formed as a part of the slider 203, but may be provided as a separate member.

The light shielding means 204 comprises an intermediate layer 204b and a reflective layer 204c.
6, a small opening 204a having a diameter smaller than the wavelength of light emitted from the light source 201 is formed in a part of the reflection layer 204c.

The light beam 210 incident on the slider 203 from the light source 201 via the optical path 202 is condensed on the lens surface 203a, and condensed near the minute opening 204a formed in the reflection layer 204c constituting the light shielding means 204. At this time, the maximum angle between the optical axis and the condensed light is determined by the intermediate layer 20.
4b is larger than the total reflection angle at the end face. Then, part of the light that is totally reflected leaks out from the end of the intermediate layer 204b as evanescent light. Normally, light waves cannot pass through apertures smaller than the wavelength,
Only the evanescent light can pass through the minute opening 204a formed in the recording medium 206 rather than the intermediate layer 204b, and the form of normal propagation light transmitted without being reflected at the end face of the intermediate layer 204b Unnecessary light having the above cannot pass through the minute aperture 204a. Therefore, ordinary propagation light, which is only stray light, does not enter the recording medium 206, so that the S / N ratio of light used for recording and / or reproduction can be improved from the minute aperture 204a, and recording or / and reproduction quality can be improved. And an information reproducing apparatus using the same can realize an information reproducing apparatus having good recording and / or reproducing characteristics.

Further, since the light beam 210 is condensed on the lens surface 203a in the vicinity of the minute aperture 204a, the amount of light leaking from the minute aperture as evanescent light can be increased as compared with the case where no light is condensed. Efficiency can be improved.

Reference numeral 205 denotes a support member. One end 205 a of the support member 205 is
Is connected to the end face on the opposite side to the face on which is provided, and the other end 205b is connected to the driving means 207. The operation of the driving means 207 is such that the evanescent light generated in the minute opening 204 a provided in the medium facing surface of the slider 203 is transmitted to the predetermined position of the recording medium 206 by transmitting the slider 203 via the support member 205. In addition, information can be recorded or reproduced. Here, as the driving unit 207, a unit that rotates around an axis such as a voice coil motor or a unit that linearly moves in the XY directions such as an actuator can be used.

Reference numeral 208 denotes a light-condensing member.
It is provided on the opposite side of the slider 203 with the recording medium 206 interposed therebetween, and functions to condense a part of the propagation light generated by the evanescent light generated in the minute aperture 204a interacting with the recording surface 206a of the recording medium 206. have.

Reference numeral 209 denotes a light receiving member.
It has a function of receiving the reproduction light corresponding to the information on the recording surface 206a condensed by the condensing means 208 and converting it into an electric signal.

Reference numeral 213 denotes a light source.
1 is provided separately from the light source 201 and emits light having a wavelength different from that of the light source 201. The light is emitted onto the recording medium 206 via an optical path 214 formed of an optical fiber or the like, and is recorded on the recording medium 206. It has the function of erasing the information. Although not shown here, at least the optical path 214 is configured to be movable from the innermost circumference to the outermost circumference of the recording surface 206a of the recording medium 206. Although not shown, a minute projection or a minute opening is formed at the tip of an optical fiber or the like constituting the optical path 214, and the structure is configured to irradiate evanescent light therefrom.

Next, a photochromic recording medium 206
Will be described.

The recording layer 206a of the recording medium 206 is formed of a photochromic material having a thermally irreversible property in which the color changes reversibly between two states by light irradiation, and both states are thermally stable. Examples of the photochromic material having thermal irreversibility include a diarylethene derivative, a fulgide derivative, and a cyclophane derivative.
In terms of thermal stability, repetitive durability, and long wavelength range sensitivity,
Diarylethene derivatives are more preferred. Among them, a symmetric or asymmetric diarylmaleimide, a symmetric or asymmetric diaryl anhydride, or a symmetric or asymmetric diarylperfluorocyclopentene having a substituted 5-membered benzothiophene or substituted indole as an aryl group is particularly preferable.

The recording medium 206 is preferably formed by dispersing these photochromic materials in a polymer. These photochromic materials, if necessary, together with a solvent such as carbon tetrachloride, benzene, cyclohexane, methyl ethyl ketone, tetrachloroethane, polyester resin, polystyrene resin, polyvinyl butyral resin, polyvinylidene chloride, polyvinyl chloride, polymethyl methacrylate, The recording medium 2 is dispersed or dissolved in a polymer such as polybutyl methacrylate, polyvinyl acetate, cellulose acetate, epoxy resin, and phenol resin.
06.

A recording layer is formed by dispersing or dissolving these photochromic materials in a polymer medium or a solvent as described above, and applying them on an appropriate substrate to form a recording layer.
It can also be 6. Furthermore, a photochromic compound is formed on a suitable substrate by a known evaporation method or a co-evaporation method with another compound to form a recording layer, or a photochromic material is dissolved in a solvent as described above,
What is enclosed in a glass cell or the like can be used as the recording medium 206.

As the substrate, glass, plastic,
General recording medium 206 such as paper, plate-like or foil-like metal
Support. When a recording layer is formed on a substrate, layers such as a lubricating layer, a reflective layer, and a protective layer can be provided as necessary.

Next, a photochromic recording medium 206
The recording of information to the server will be described.

The light emitted from the light source 201 is
The light is converted into convergent light at 11, is reflected by the reflection mirror 212, and becomes a light flux 210 as the lens surface 203 of the slider 203.
a. The light flux 210 is converted into convergent light having a larger NA by the lens surface 203a, and
The light is condensed in the vicinity of the minute opening 204a of the light shielding means 204 formed on the third medium facing surface. And the minute opening 204
Evanescent light is generated from a. The evanescent light is locally applied to the photochromic recording medium 206 to perform recording. That is, by driving the driving unit 207 to move the slider 203 having the minute opening 204a to a predetermined position and blinking the light source 201 in accordance with the input information, the portion of the recording medium 206 irradiated with the evanescent light is erased from the colored state. A change to the color state is induced and information is recorded.

Next, information reproduction will be described. Light source 2
01 from the slider 2 through the optical path 202.
The light is converged to the vicinity of the minute aperture 204a by the lens surface 203a to generate evanescent light. At this time, the intensity of the transmitted light generated by the interaction between the evanescent light and the recording surface is the intensity of the transmitted light in the portion that has changed to the decolored state due to the recording, and the intensity of the transmitted light in the portion that has not changed in the colored state. Therefore, the difference between recorded pits and unrecorded pits, that is, recorded information can be read from the difference in transmitted light intensity. Therefore, the light transmitted through the recording medium 206 is collected by the light collecting member 208 to reproduce information.

The light source used was the light source 20 used for recording.
Light having a wavelength different from 1 may be introduced and used. In addition, the light emitted from the light source 201 may be subjected to intensity modulation or position modulation in the Z-axis direction. Further, in the present embodiment, the configuration is such that light transmitted through the recording medium 206 is detected. However, a reflection film is formed on the recording surface 206a of the recording medium 206, and the light is reflected by the recording medium 206. It may be configured to detect light.

Next, the erasure of information will be described. Light source 2
13 is emitted from the recording medium 2 via the optical path 104.
06. Here, the wavelength of light emitted from the light source 213 is shorter than the wavelength of light emitted from the light source 201.
As a result, all the portions of the recording medium 206 to which the light has been irradiated are in a colored state. Thus, the recorded information can be erased.

Although the light source 201 and the light source 213 are provided at different places, they may be provided at the same place and switched to be used so that the optical path 202 and the slider 203 are shared.

As described above, by using a photochromic material having thermal stability as a recording material and evanescent light having a size smaller than the wavelength as a light source, the current optical recording can be performed depending on the size (10 to 100 nm) of the evanescent light. The recording can be performed at a density 200 to 20,000 times as large as the recording density.

In the present embodiment, the light source 201 and the optical path 202 are provided separately from the slider 203, but the light source 201 and the optical path 202 may be provided on the slider 203. Further, the light source 201 and the optical path 202 are provided on the support member 205 and the driving unit 207, and the slider 2
03 may be linked. By providing the light source 201 and the optical path 202 in the slider 203, the support member 205, or the driving means 207 in this manner, light from the light source 201 can be surely made to enter a predetermined position of the moving slider 203, so that information Reproduction is reliable and the seek time can be shortened, and the light source 201 and the optical path 202
Since the mechanism for following the operation can be simplified, an optical head with high productivity and high reliability can be obtained.

Next, the slider 203 according to this embodiment will be described.
The configuration of the light shielding means 204 will be described in detail.
FIG. 8 is a diagram showing a configuration of a slider according to the embodiment of the present invention. In FIG. 8, rail surfaces 203b and 203c are formed on the medium facing surface side of the slider 203, respectively.
4 are formed.

The slider 203 has a function of smoothly moving the optical head on the recording medium 206. As the type of the slider 203, a sliding type used in contact with the recording medium 206 or a floating type used in a state of floating above the recording medium 206 may be used. Further, among the floating types, a contact start / stop method for starting and stopping the apparatus while the slider is in contact with the recording medium 206, a self-loading type floating head slider mechanism for starting and stopping without contact, a slider lifting / lowering Mold loading / unloading mechanism,
There is a non-contact type such as a ramp load type load / unload mechanism.

The surface of the slider 203 is
The fact that light from the slider 203 is shielded by the light-shielding means 204 having light absorption characteristics at a portion other than the portion where the light from the light is incident and the portion other than the minute opening 204a causes light (stray light) leaking from the slider 203 and having no relation to recording or reproduction (stray light). 209 can be suppressed as noise, and the S / N ratio can be suppressed from deteriorating. Further, the light reflected by the reflection layer 204c of the light shielding means 204 is repeatedly reflected inside the slider 203 to form an optical path. This is preferable because it is possible to suppress the occurrence of inconveniences such as mixing in the light beam 210 and interfering with the light beam 210, or entering the light source 201 and causing unstable output from the light source 210.

The light shielding means 204 has a minute opening 204a, an intermediate layer 204b, and a reflective layer 204c, and the minute opening 204a generates evanescent light as described above. In contrast, the intermediate layer 204b and the reflective layer 204c
The micro aperture 204a has a function of blocking light other than light contributing to generating evanescent light, and suppressing generation of light (stray light) leaking toward the recording medium 206.

Here, particularly, the reflection layer 204c has a reflection characteristic and has a function of reflecting incident light. Therefore, the reflection layer 204c is formed of a material having a high reflectance with respect to the wavelength of the light source 201, and is used to prevent the reflection layer 204c from being damaged by light collected around the light shielding unit 204 by the lens surface 203a. , High thermal conductivity and heat release are required. Further, the size of the minute opening 204a changes or the intermediate layer 204b and the reflective layer 204c are destroyed due to thermal stress distortion generated due to a temperature difference or a difference in thermal expansion coefficient between the intermediate layer 204b and the intermediate layer 204b. It is necessary to pay attention to the thermal expansion and the like in order to prevent the occurrence of such a phenomenon.

Further, the intermediate layer 204b has a fine opening 204a.
Is provided between the reflective layer 204c where the light is concentrated and the temperature becomes high and the slider 203 which is a relatively low temperature, and absorbs the difference in temperature and expansion between the reflective layer 204c and the slider 203, It has a function of alleviating the stress caused by heat and suppressing the occurrence of inconveniences such as a change in the shape of the minute opening 204a and breakage of the reflective layer 204c.

Therefore, when the characteristic values of the intermediate layer 204b, the reflective layer 204c, and the slider 203 are compared and examined, it is preferable that the characteristic values are set as follows.

First, the thermal conductivity (rate) is determined by the minute opening 204a.
The reflective layer 204, which concentrates light and generates a large amount of heat,
c, which is highest, adjacent to the reflective layer 204c,
4a and the intermediate layer 204b in contact with the reflective layer 204c and the slider 203 in contact with the intermediate layer 204b are reduced in this order, so that the generated heat can be efficiently dissipated.
This is preferable because the occurrence of inconveniences such as deformation and melting of the light shielding means 204 due to heat can be suppressed. In addition, by using a material whose thermal conductivity increases with an increase in temperature, the heat dissipation of a portion where heat is generated can be improved with an increase in temperature. Breakage of the light shielding means 204 can be suppressed more efficiently, and a more reliable optical head can be obtained.

Next, it is preferable that the heat release into the atmosphere is also reduced in the order of the light-shielding film 204c, the intermediate layer 204b adjacent to the light-shielding film 204c, and the slider 203, which generate a large amount of heat. In particular, the heat release property of the light-shielding film 204c is set to be at least twice as large as that of the intermediate layer 204b and the slider 203, so that the temperature rise of the light-shielding film 204c can be suppressed. This is preferable because breakage can be greatly suppressed.

Finally, it is preferable that the thermal expansion (linear expansion coefficient) of both the light shielding means 204 and the slider 203 is small, and that the difference is small. Also, the intermediate layer 204
b is the linear expansion coefficient of the slider 203 and the reflection layer 2.
04c can be set between the linear expansion coefficients.
3 and the difference in the coefficient of linear expansion between the intermediate layer 204b and the intermediate layer 20b.
Since the difference in the coefficient of linear expansion between the reflective layer 4b and the reflective layer 204c can be made smaller, it is possible to suppress inconveniences such as cracks caused by the difference in the respective coefficients of expansion. .

In particular, the size such as the opening diameter of the minute opening 204a defined by the reflective layer 204c is slightly changed according to the expansion and contraction of the reflective layer 204c. Especially the small aperture 2
In a state where evanescent light is generated from the light emitting element 04a, if the minute opening 204a becomes small due to the expansion of the reflecting layer 204c when the temperature of the reflecting layer 204c becomes high, if it changes in proportion to the opening diameter, Since the conceivable arrival distance of the evanescent light is also shortened, it is difficult to form the evanescent light so as to be in contact with the recording medium 206, and it becomes impossible to perform recording or reproduction. Therefore, the range of the linear expansion coefficient that the reflective layer 204c should satisfy is required to be a range in which the change in the size of the minute opening 204a can record and reproduce information using the evanescent light. The rate of change when comparing the linear expansion coefficient when the light is increased, that is, when the reflective layer 204c is at a higher temperature, with the linear expansion coefficient when the light is not irradiated, that is, when the reflective layer 204c is at a lower temperature. The use of a material having a value within 20% can minimize the change in the amount of change in the shape of the reflective layer 204c due to the temperature state, and can stabilize the reach of evanescent light. Therefore, reproduction with stable evanescent light or /
And recording can be performed.

The slider 20 satisfying the above characteristics
3 and the following materials can be considered as materials of the intermediate layer 204b and the reflective layer 204c.

First, the slider 203 is formed of a material having a light-transmitting property such as resin or glass, and in particular, a material having a transmittance of 90% or more at the wavelength of light from the light source 201 here. This is preferable because evanescent light can be generated without lowering the light emission. In particular, since glass has a large strength, by using it as a material for forming the slider 203, which may possibly come into contact with the recording medium 206, it is less likely that the glass will be damaged even if it comes into contact with the recording medium 206. This is preferable because a highly reliable slider can be realized. Also, among glass materials, in particular, it has sufficient strength, has a small coefficient of thermal expansion,
Quartz glass, which has almost no change in coefficient of thermal expansion from low to high temperatures, is the most suitable material.

Next, the intermediate layer 204b is located between the slider 203 and the reflection layer 204c, and is often formed mainly of a material such as glass, resin, or metal. It is often determined accordingly. For example, when the slider 203 is formed of a glass material and the reflection layer 204c is formed of a metal material,
4b is made of a glass material or a metal material, so that the difference in the coefficient of thermal expansion can be suppressed to a minimum. Can be suppressed. As an optimal combination, when quartz glass is used for the slider 203, lead glass or Pyrex glass can efficiently absorb the difference in thermal expansion between the slider 203 and the reflective layer 204c particularly in a high temperature state. It is preferred. The thickness of the intermediate layer 204b is preferably about 10 nm to 1000 nm, because the difference in thermal expansion between the slider 203 and the reflective layer 204c can be efficiently absorbed. Also,
It is preferable that the intermediate layer 204b is also formed of a translucent material. By forming the intermediate layer 204b with a light-transmitting material, the position where evanescent light is generated can be near the interface between the intermediate layer 204b and the reflective layer 204c. Therefore, the distance from the evanescent light generating portion to the recording medium 206 can be made shorter than in the case where the light is generated on the lower surface of the slider 203, so that the distance control between the recording medium 206 and the slider 203 is more easily performed. It is preferable because it can be used.

Next, the reflection layer 204c is mainly made of Au, Ag, A
Metal materials such as l and Cu, SIO ₂ and TiO ₂
In many cases, it is formed of a material having a property of reflecting light, such as a combination of dielectric materials such as. When the film thickness is about 10 nm to 100 nm, light can be prevented from leaking from a portion other than the minute opening 204a, and the evanescent light generated in the minute opening 204a is applied to the surface of the reflective layer 204c facing the recording medium 206. This is a preferable configuration since the recording medium 206 can be more reliably projected toward the recording medium 206 side, and information can be recorded and / or reproduced with the projected evanescent light more reliably.

In the present embodiment, since the intermediate layer 204b has high translucency, the minute opening 204a is
04c. Middle layer 204
b has a light shielding characteristic,
Is preferably formed to penetrate the intermediate layer 204b and the reflective layer 204c.

Further, the light shielding means 204 has a two-layer structure of the intermediate layer 204b and the reflection layer 204c. However, the light shielding means 204 may have a three or more layer structure, and the reflection layer 204c is optimized for heat conductivity, linear expansion coefficient and the like. When a functionally graded material is used, or when the difference between the material constituting the slider 203 and the thermal conductivity or the coefficient of linear expansion is small, the intermediate layer 204b can be omitted.

As described above, in the present embodiment, a part or the whole of the slider 203 is formed of a translucent member, and the minute opening 204a for generating evanescent light is formed in the medium facing surface. With this configuration, the slider 203 itself can be used as a means for generating the evanescent light. Therefore, compared with a case where evanescent light generating means such as a probe is provided separately, the positioning between the slider and the slider can be adjusted. Can be eliminated, and the number of parts and assembly man-hours can be reduced.
An optical head with extremely high product accuracy and high productivity can be realized.

Further, since the slider 203 is entirely or partially formed of a translucent member, strict alignment between the optical path 202 and the minute opening 204a and the slider 20 can be achieved.
3. Even if a hole for transmitting light is not provided in
Since the light can be guided to the slider 4a, the configuration of the optical head can be simplified.
The optical head can be installed anywhere as long as it is the medium facing surface, so that the degree of freedom in designing the optical head can be ensured.

Next, referring to FIGS.
A method of cooling around the area 04a will be described.

FIG. 9 is a sectional view of an optical head according to Embodiment 2 of the present invention. Referring to FIG.
And the reflection layer 204c formed on the surface of the slider 203 has a medium facing surface of the slider 203 via the side surface of the slider 203 as well as the medium facing surface of the slider 203 in which the minute opening 204a is formed. It is extended to the opposite side of the surface. And in this embodiment,
The reflective layer 204c not only has a function of reflecting the incident light so that the light incident from the slider 203 does not leak toward the recording medium 206, but also has a particularly high thermal conductivity. The heat generated around the opening 204a can be particularly effectively removed by conduction. That is, the reflection layer 204c plays a role as a thermal wiring.

Further, the supporting member 205 for supporting the slider 203 may have a function as a heat pipe.
By bringing the reflection layer 204c into contact with the support member 205, heat generated around the minute opening 204a can be efficiently discharged to the outside by conduction. In particular, as shown in FIG. 9, by adopting a configuration in which the reflection layer 204c is interposed between the slider 203 and the support member 205,
The heat from the reflection layer 204c is more efficiently supported by the support member 205.
Can be conducted.

More preferably, a metal bonding material having a high thermal conductivity is used as a bonding material used for bonding the support member 205 and the slider 203. The reflection layer formed on the surface of the support member 205 and the slider 203 is preferably used. The thermal resistance between the reflective layer 204c and the reflective layer 204c can be reduced.
This is preferable because the manner in which heat is transmitted from the support member 205 to the support member 205 can be improved.

Next, referring to FIG.
Another cooling method for the periphery will be described.

FIG. 10 is a sectional view of an optical head according to Embodiment 2 of the present invention. In FIG. 10, reference numeral 220 denotes a cooling member. The cooling member 220 is formed of a Peltier element, and is joined to a side surface of the slider 203 to cool the slider 203 which has become hot. Especially the minute opening 204c
Is formed on the side surface of the slider 203 so as to be in contact with the cooling member 220. More preferably, the reflection layer 204c is sandwiched between the slider 203 and the cooling member 220, so that the temperature is particularly high. The cooling around the small opening 204a can be efficiently performed. Further, in the present embodiment, the cooling member 220 is provided on the side surface of the slider 203, but may be provided on the fluid inflow end side or the fluid outflow end side of the slider 203, or may be formed on a plurality of surfaces. Further, by configuring the slider 203 with an insulating material, wiring for the cooling member 220 can be printed on the slider 203, and power can be easily supplied to the cooling member 220. Further, a wiring can be provided separately, but a part of the reflection layer 204c can be divided and used as a wiring.

Next, another method of cooling the periphery of the minute opening 204a will be described with reference to FIGS. FIG. 12 is an enlarged view of the evanescent light generating means according to the second embodiment of the present invention, and FIG. 13 is an enlarged view of the evanescent light generating means according to the second embodiment of the present invention.

In FIG. 12, a fine opening 20 is formed on a rail surface 203c of a slider 203 via an intermediate layer 204b.
As described above, the reflection layer 204c having the layer 4a is formed. In the present embodiment, particularly when the thickness of the reflective layer 204c is 20 to 50 nm,
(The difference between the protrusion peak value and the concave peak value, i.e. shall be defined by R _max.) Surface roughness of the bearing surface of 1nm
It has been confirmed that excellent characteristics can be realized by forming the film to a thickness of 25 nm or less.

That is, by adopting such a configuration, the spacing between the optical head and the recording medium 206 is appropriately secured, the evanescent light is favorably generated, and the surface area of the reflective layer 204c, which becomes high in temperature, is increased. Since the size can be increased, the cooling efficiency of the reflective layer 204c can be further improved. In particular, by forming the surface roughness to be 1 nm or more, the reflective layer 204c directly facing the recording medium 206 can be used for recording. It is possible to reduce the possibility that suction will occur when the recording medium 206 comes into contact with the medium 206, and to prevent a situation in which the optical head and the recording medium 206 are sucked and become inoperable. By setting the surface roughness to 25 nm or less, it is possible to minimize the generation of dust from the reflective layer 204c during operation, which is caused by the increase in the roughness. In addition, the thickness of the reflective layer 204c needs to be set so as to sufficiently reflect incident light even in the thinnest place. As the ideal range of the surface roughness that satisfies all of these conditions, it is most preferable that the range of the surface roughness when the thickness of the reflective layer 204c is d be 0.05 d or more and 0.5 d or less. . With such a range, the spacing between the optical head and the recording medium 206 can be reduced, the occurrence of adsorption between the optical head and the recording medium 206 can be suppressed, and the cooling efficiency of the evanescent light generating means can be reduced. Can be improved, and the generation of dust can be suppressed.

In the present embodiment, the surface roughness of the reflection layer 204c is different between the vicinity of the minute opening 204a and the other portion. That is, the configuration is such that the surface roughness near the minute opening 204a is larger than that of the other portions. Accordingly, the surface area around the minute opening 204a where the temperature becomes particularly high in the reflective layer 204c can be further increased, so that the cooling efficiency around the minute opening 204a can be further improved.

Further, in accordance with the heat distribution of the reflection layer 204c at the time of light incidence, it is most efficient to cool the reflection layer 204c as the surface roughness increases as it approaches the minute opening 204a. It is preferable because it can be used.

In this case, the reflection layer 204c is formed on the intermediate layer 20.
4b, but on the rail surface 2 of the slider 203.
Of course, it is also possible to form directly on 03c. Also, the rail surface 203c (if there is an intermediate layer, the intermediate layer 204
By setting the surface roughness of b) to 10 nm or more, the contact area with the reflective layer 204c formed thereon increases, and the heat generated in the reflective layer 204c can be released to the slider 203 side. , Can contribute to the cooling of the reflective layer 204c.

The structure shown above is the light shielding means 204.
Can be applied not only to the case where is formed by the reflection layer 204c, but also to the case where it is formed by the light absorption layer and the scattering layer.

As shown in FIG. 12, the reflection layer 204c
May be formed stepwise. That is, the thickness of the reflective layer 204c around the minute opening 204a, which becomes high in temperature due to the collected light, is formed. With this configuration, it is possible to further increase the heat capacity around the minute opening 204a, which is particularly high in temperature, while reliably blocking the light incident on the slider 203, so that the reflective layer 204c is deformed by heat and the opening of the minute opening 204a is increased. Changes in bore size can be minimized. Further, with this configuration, the minute aperture 204
Since the surrounding reflective layer 204c can be configured to protrude as compared with the surroundings, the flow of fluid generated with the rotation of the recording medium 206 can be more efficiently reflected by the reflective layer 204c.
Can be applied to the portion where the temperature has become high, so that the cooling around the minute opening 204a can be performed more efficiently.

[0132]

As described above, according to the present invention, since the cooling member is provided around the evanescent light generating means, it is possible to cool the evanescent light generating means, which becomes high in temperature by irradiation of light, so that the evanescent light generating means can be cooled. The means is not excessively heated, so that the reliability of the optical head can be improved, and the reliability of the information reproducing apparatus equipped with the optical head can also be improved.

By setting the surface roughness around the evanescent light generating means within a predetermined range, the surface area around the evanescent light generating means, which becomes particularly high in temperature, can be increased, so that the cooling efficiency is further improved. Can be.

[Brief description of the drawings]

FIG. 1 is a diagram showing an information reproducing apparatus according to Embodiment 1 of the present invention.

FIG. 2 is a diagram showing a configuration of a slider according to the first embodiment of the present invention.

FIG. 3 is a sectional view of a cooling member according to the first embodiment of the present invention.

FIG. 4 is a plan view of a cooling member according to the first embodiment of the present invention.

FIG. 5 is a plan view of a cooling member according to the first embodiment of the present invention.

FIG. 6 is a plan view of the cooling member according to the first embodiment of the present invention.

FIG. 7 is a diagram showing an information reproducing apparatus according to Embodiment 2 of the present invention.

FIG. 8 is a diagram showing a configuration of a slider according to the second embodiment of the present invention.

FIG. 9 is a sectional view of a cooling member according to the second embodiment of the present invention.

FIG. 10 is a sectional view of an optical head according to a second embodiment of the present invention.

FIG. 11 is a control block diagram of the information reproducing apparatus according to the first embodiment of the present invention.

FIG. 12 is an enlarged view of an evanescent light generating unit according to the second embodiment of the present invention.

FIG. 13 is an enlarged view of an evanescent light generating unit according to the second embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 101 Light source 102 Optical path 103 Slider 103a, 103b, 103c Rail surface 104 Light shielding means 104a Micro opening 104b Intermediate layer 104c Light shielding layer 105 Support member 105a, 105b End part 106 Recording medium 107 Driving means 108 Light collecting member 109 Light receiving member 110 Light beam 111 Medium Driving means 120 Cooling member 120a Projecting part 121 Control means 122 Driving means state detecting means 123 Memory means 124 Light source controlling means 201 Light source 202 Optical path 203 Slider 204 Light shielding means 204a Micro opening 204b Intermediate layer 204c Reflecting layer 205 Supporting members 205a, 205b 206 Recording medium 207 Driving means 208 Light condensing member 209 Light receiving member 210 Light flux 211 Lens 212 Reflecting mirror 213 Light source 214 Optical path 220 Cooling member

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masuki Ogushi 1006 Ojimon Kadoma, Kadoma-shi, Osaka Matsushita Electric Industrial Co., Ltd. Terms (reference) 5D119 AA11 AA22 DA01 DA05 DA07 FA32 JA36 JA60 MA09

Claims (13)

[Claims] A light source, an optical system for guiding light from the light source to a predetermined position, evanescent light generating means for generating evanescent light from light guided by the optical system, and evanescent light generating means. Holding means for holding, driving means for moving the holding means to a predetermined position on a recording medium, and light receiving means for receiving light generated by interaction between evanescent light and a recording surface of the recording medium. An optical head, wherein a cooling member is provided near the evanescent light generating means. 2. The optical head according to claim 1, wherein the cooling member is constituted by at least one of a protrusion, a heat pipe, a heat wiring, and a Peltier element. 3. A light source, an optical system for guiding light from the light source to a predetermined position, evanescent light generating means for generating evanescent light from light guided by the optical system, and evanescent light generating means. Holding means for holding, driving means for moving the holding means to a predetermined position of the recording medium, light receiving means for receiving light generated by the interaction between the evanescent light and the recording surface of the recording medium,
A cooling member provided around the evanescent light generating means, wherein the evanescent light generating means is provided by applying a flow of a fluid generated with rotation of the recording medium to the cooling member. An optical head characterized by cooling. 4. The cooling member is formed to be longer in the direction and shorter in a direction perpendicular to the direction with respect to the direction in which the fluid generated by the rotation of the recording medium flows. 3. The optical head according to 3. 5. The cooling member according to claim 3, wherein the cooling member has at least one position substantially parallel to a direction in which a fluid generated by rotation of the recording medium flows.
An optical head according to any one of the preceding claims. 6. A light source, an optical system for guiding light from the light source to a predetermined position, evanescent light generating means for generating evanescent light from light guided by the optical system, and evanescent light generating means. Holding means for holding, driving means for moving the holding means to a predetermined position of the recording medium, and light receiving means for receiving light generated by the interaction between the evanescent light and the recording surface of the recording medium, An optical head, wherein the surface roughness of the medium facing surface of the evanescent light generating means is set to 1 nm or more and 25 nm or less. 7. The optical head according to claim 6, wherein the surface roughness increases as it approaches the light emitting portion of the evanescent light generating means. 8. The optical head according to claim 6, wherein the surface roughness is different between the vicinity of the light emitting portion of the evanescent light generating means and the other portion. 9. An optical head according to claim 1, wherein said holding means comprises a slider. 10. A light-shielding means is formed on a medium facing surface of a slider made of a light-transmitting member, and a minute opening is formed in said light-shielding means to form a light-emitting portion of an evanescent light generating means. The optical head according to claim 9. 11. The optical head according to claim 10, wherein the surface roughness in the vicinity of the minute opening is set to 0.05 d or more and 0.5 d or less with respect to the thickness (d) of the light shielding means. 12. An optical head according to claim 1, wherein said optical head according to claim 1 irradiates evanescent light onto said rotating recording medium by a medium driving means for holding and driving said recording medium. An information reproducing apparatus for reproducing information. 13. The information reproducing apparatus according to claim 12, wherein light is made incident on the evanescent light generating means after confirming a state of the recording medium.