JPH02113433A - Optical input/output device - Google Patents

Abstract

PURPOSE:To prevent dust and waste larger than the distance between a light transmitting means of an optical recorder or the optical input-output device and the surface of an optical recording medium and floating in air from getting into the recorder or input-output device so as to improve the reliability of the recorder or device by reducing the distance between the light transmitting means and the surface of the medium to less than a prescribed value by means of a relatively moving gas at least at the information recording time. CONSTITUTION:The optical head 5 of this optical input-output device is smoothly moved vertically or in a direction at a fixed angle against the vertical direction. When the head 5 is moved, an optical recording medium 1 is first moved in the direction shown by the arrow 4 at a speed of about 1-50m/sec in air of a fixed air pressure and a prescribed pressure is applied between the medium 1 and a back plate 3 by using a spring supporting the head 5 so that a stable air moving layer can form a gap 15 between the medium 1 and a slider 2. The gap 15 formed on the surface of the slider 2 facing the medium 1 is maintained at a fixed value of <=0.02mum by forming an air staying section and changing the area, curvature, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to the configuration of an optical input/output portion of an optical storage device or an optical recording device.

[Conventional technology]

Conventional optical input/output devices condense light emitted from a light emitting device such as a laser into a predetermined beam diameter using a group of lenses, and irradiate the light directly onto the surface of an optical recording medium.

[Problem to be solved by the invention]

However, in the above-mentioned conventional technology, in order to avoid damage to the recording medium due to contact between the lens group and the surface of the optical recording medium, electrical and mechanical control is performed to prevent the lens group surface and the recording medium surface from contacting each other and damaging the recording medium. It was necessary to maintain a constant distance by a large distance, which required a complicated drive system. Furthermore, in order to facilitate the control, the distance is set to 1 to
They were separated by more than 2 mm to prevent any mechanical damage. Therefore, it is easy for dust to enter between the lens group and the optical recording medium from the air, and the mixed dust is focused by the lens group and scatters the light irradiated onto the surface of the optical recording medium, thereby providing reliable optical information. There was a technical issue in that it was not possible to record.

In addition, even if the irradiated light is narrowed down by a group of lenses in order to improve the recording density, the smaller the particle size of the dust in the air, the greater the amount of dust present in the air, which increases the scattering rate of light and makes it difficult to write optical information. There were also serious technical issues such as instability and reduced reliability.

The present invention is intended to solve these technical problems, and its purpose is to stably maintain a constant distance between an optical recording medium and an optical input/output device with a simple configuration without the need for a complicated control device. An object of the present invention is to provide an optical input/output device that can stably write and read optical information without being affected by dust in the air.

[Means to solve the problem]

The light input/output device of the present invention mainly includes at least one light emitting means, a light transmitting means, a condensing means, and at least one light detecting means, and is configured to detect light emitted from the light emitting means. , condensing light by the condensing means and irradiating it onto the surface of the optical recording medium through the light transmission means to record information;
Alternatively, in a light input/output device that irradiates information locally recorded on the optical recording medium and reads reflected light with the light detection means, the light transmitting means and the surface of the optical recording medium may be relatively It is characterized in that it is installed at a distance of 10 μm or less with a moving gas interposed therebetween, at least when recording the information.

[Effect]

According to the above configuration of the present invention, the distance is set to a predetermined value of 10 μm or less simply by interposing a relatively moving gas between the light transmitting means and the surface of the optical recording medium and applying a predetermined pressure. This not only makes it possible to form a stable laminar flow of gas so that the light transmitting means can stably follow the deflection and vibration of the optical recording medium, but also allows the light transmitting means to stably follow the deflection and vibration of the optical recording medium. It is possible to record and read optical information with high reliability while preventing the intrusion of dust and dirt in the air.

[Example 1] FIG. 1 is a schematic configuration diagram showing one embodiment of the present invention.

The optical recording medium 1 is placed between the slider 2, which is a light transmitting means, and the back plate 3, and while pressing the slider 2 against the optical recording medium 1 with a spring (not shown in the figure),
It was moved in direction 4 at a speed of 0 m/s. A flat surface was formed on the slider 2, and an optical head 5 containing a light irradiation means and a light detection means was installed so as to move smoothly on the surface. The optical head 5 is connected to a writing/reading amplifier 6 by a code 7, and further uses a pulse motor and a linear encoder (not shown in the figure) to move the recording band of the optical recording medium 1 roughly in the track direction 8. It is now possible to move to the position of

Next, an overview of the operation of the optical recording/reading device used in the present invention will be explained. When reading optical recording, optical recording medium 1
The track position and the information position were confirmed while reading the reference information 9 pre-recorded near the end with the optical head 5 at appropriate times, and the recorded information 10 was written or read. In this case, the reference information 9 does not have to be near the end,
It may be installed for each signal track.

Next, the configuration and operation of the present invention will be explained using FIG. 2.

The optical head 5 mainly consists of a semiconductor laser 11, condensing lens groups 12 and 13, a semi-transparent mirror 18, and a photodetector 14, and the optical head 5 is arranged vertically on the slider 2 in the figure or in a direction having a certain angle with the vertical direction. I was able to move smoothly. First, move the optical recording medium 1 in direction 4 in air at a constant pressure.
When the back plate 3 was moved at a speed of ~50 m/sec, the back plate 3
Even though a predetermined pressure was applied between the optical recording medium 1 and the slider 2, a stable air fluid layer was formed between the optical recording medium 1 and the slider 2, and a gap 15 was stably formed as shown in the figure. The gap 15 can be changed depending on the size and shape of the slider 2, the speed of the optical recording medium 1, the air pressure, the pressure of the spring, etc. In this experiment, a groove was mainly formed on the surface of the slider 2 facing the optical recording medium 1. to form or
By forming an air pocket (sink part) or by changing the area, curvature, etc.
It was possible to stably maintain a constant value of ~2 μm). At this time as well, no mechanical damage was observed on the surface of the recording medium 1.

Furthermore, when the above experiment was conducted with this device installed in a vacuum chamber of 10 Pa or less, the slider 2 and the optical recording medium 1 came into contact with each other, resulting in mechanical pressure marks and pressure marks formed on the surface of the optical recording medium 1. Damage has occurred. Next, when we filled the chamber with a gas such as nitrogen or argon, which has a different composition from air, and conducted the experiment again, the above contact was not observed.
The slider 2 floated stably, and no mechanical damage was observed on the surface of the optical recording medium 1. Gap 15 is light 1 of slider 2; C! If the shape of the part facing the recording medium 1 is kept constant, if the pressing pressure by the spring exceeds a predetermined value, it will remain almost constant even with variations in pressure, and is extremely stable even with variations in spring characteristics. was able to be held constant. Furthermore, by changing the material and shape of the spring, it was possible to keep the gap 15 constant and follow the changes in thickness and waviness of the optical recording medium 1. In this embodiment, the optical recording medium By moving slider 1 in direction 4, a stable layer of flowing gas is formed between it and back plate 3, and the gap can be stably maintained at a constant value, resulting in the same shape change and gas flow as with slider 2. Slider 2 used in this example also achieved the effect of
The glass and sapphire materials on the surface closest to the optical recording medium 1 are coated with a surface roughness of 0.01 μm (MA
X) The following ultra-precision processing was performed and formed. The back plate 3 is made of a ceramic material, a hard-treated metal material, etc., and is processed to have a surface roughness of 0.01 μm or less. The optical recording medium 1 is made of a flexible sheet such as polyester, and is coated with a material whose light transmittance changes depending on light or heat, and is coated with a thickness of 0.05 μm.
~1 μm in thickness, and a protective layer or lubricating layer of 0.1 μm in thickness.
It was used after being formed to a size of less than m. Also, good results were obtained when the slider 2 and the back plate 3 were made of plastic or surface hardened plastic.

Next, after forming a constant and stable gap 15 as described above, the write amplifier 6-1 caused the semiconductor laser 11 to emit light of high intensity in a pulsed manner according to the write information. Here, the semiconductor laser 11 includes a gold-plated stem 16 and an electrode 17 electrically separated from the stem 16.
-1, an electrode 17-2 electrically connected to the stem 16, a conductive heat sink 19, a laser diode chip 20 wired as shown in FIG. 2, and a window 22. A light emitting part of a diode chip in the semiconductor laser 11 is installed on the optical axis 21 of the optical head 5, and the light 23 from the light emitting part is directed to the optical recording medium 1 by the condensing lens group 12.
When the light was focused on the light focusing portion 24 on the front surface, the recorded information 10 could be successfully written onto the optical recording medium 1 using the above-mentioned high-intensity pulsed light. At this time,
The gap 15 is 0.12±0.05 μm, and even if the focal length and aperture of the condensing lens group 12 and the size of the slider 2 are changed to make the size of the condensing part 24 about 0°5 μm, the gap remains very small. It was possible to obtain a low error rate of writing in a normal room.

When reading recorded information that has been written in advance, the semiconductor laser 11 emits light with low current and low intensity, and the light is focused on the condensing section 24 in the same manner as described above to read the recorded information 10' that has been written in advance. The zero reflected light 25, which is obtained by reading the intensity difference between the reflected light 25 between the recording area and the non-recording area with the photodetector 14, is detected by changing the aperture and focal length of the condensing lens group 13 equipped with a slit. 14 so that the S/N ratio would be good. The read optical signal was sent from the photodetector 14 to the reading amplifier 6-2 via the signal line 26. In this embodiment, a laser beam of the same wavelength is used for writing and reading, but a semiconductor laser of a different wavelength, a light emitting diode, a lamp light source, etc. may be installed as a reading light source in or near the semiconductor laser 11. Alternatively, the gap 15 may be formed by forcibly blowing gas.

[Embodiment 2] FIG. 3 is a schematic cross-sectional view showing one example of another embodiment of the present invention. In order to make the figure easier to read, some parts equivalent to those in FIG. 2 are omitted. The features of this embodiment are that a flat sensor is used as the photodetector 14' and that a semiconductor laser light source 28 for reading is separately provided. The rest is the same as in Example 1.

Next, the configuration and operation of this embodiment will be explained with reference to FIG. 3(a). In the same manner as in Example 1, a semiconductor laser is used to emit high-intensity writing light 23', and the condenser lens group 1
The recording information 10 was written onto the optical recording medium 1 by condensing the light onto the condensing section 24 using the optical recording medium 2. At this time, the writing light 23'
By passing the light through the slit 31, unnecessary stray light was removed and recording information with good contrast could be written. Next, the case of reading the recorded information 10' will be explained. In FIG. 3, the signal line for transmitting the signal of the photodetector 14' and the reading amplifier are omitted for the sake of clarity. In the same manner as in Example 1, the gap 15 of the slider 2 was set to a constant value of 10 μm or less from the optical recording medium 1,
Using the driving power supply 27 of the reading light source, a semiconductor laser beam WJ for reading with a wavelength different from that of the writing light 23' is generated.
28 was caused to emit light, and a reading light 30 was focused near the light focusing portion 24 using a focusing lens group 29 as shown in the figure. When the photodetector 14' was operated at this time, it was not only possible to read the difference in the intensity of reflected light between the recorded portion and the non-recorded portion of the recorded information 10' with very high sensitivity, but also to The moving direction of the object could also be recognized by using a plurality of photodetectors 14'. Furthermore, by calculating the sum or difference of the output signals of each of the plurality of photodetectors 14', the influence of unevenness of the optical recording medium 1 can be reduced, and the recognition rate can be improved even when the recorded information 10' is weak. I was able to do it. In this way, in this example, there was no damage caused by the light from the reading light source, and reading could be performed with further improved reliability.

Next, details of the photodetector 14' of this embodiment will be explained with reference to FIG. 3(b). As shown in the figure, an aluminum thin film electrode 32 is placed on the surface of the slider 2, which is an electrical insulator, to a thickness of 0. It was formed to have a thickness of 5 to 2 μm. Next, the photodetection layer 33,
An insulating layer 34 and a transparent electrode 35 were formed one after another, and finally a protective layer 36 was formed. The photodetection layer 33 is made of an amorphous silicon thin film with a thickness of 0.3 to 2.0 nm using the CVD method.
It was formed into a thin film photodiode with a thickness of μm. The insulating layer 34 is also 5if2 or 5isN by i,m CVD method.
4 thin film having a thickness of 0.3 to 2 μm, or by coating a polyimide-based organic material to a thickness of 0.5 to 2 μm. The transparent electrode 35 was formed by reactive vapor deposition or sputtering of indium and tin oxides in an oxygen atmosphere to a thickness of 0.1 to 1 μm. The protective layer 36 is formed to a thickness of 1 by using melt coating of powdered glass, screen printing, and heating and baking.
It was formed to have a thickness of ~20 μm.

When writing, the writing light 23' is focused on the light condensing section 24, and when reading the recorded information 10', the reading light 30 is focused on the light concentrating section 24 and reflected on the surface of the optical recording medium 1. The reflected light 37 was made to enter the photodetecting layer 33.

In this embodiment, writing and reading may be performed simultaneously, or recorded information may be erased or attached information may be recorded at an appropriate timing. Further, the optical axes of the reading light 30 and the writing light 23' may be shifted.

Alternatively, a mechanism may be used in which a constant gap 15 is formed only during recording or reading.

〔Effect of the invention〕

As described above, according to the present invention, high-density information can be written and read stably and with high reliability using a simple configuration, without requiring complicated control, and without being affected by dust in the air. In addition, even if there are variations in the thickness of the optical recording medium, it can be followed well and highly reliable writing and reading can be performed. Furthermore, the effect of reducing damage to the optical recording medium was also obtained.

Furthermore, writing and reading can be easily performed at the same time, making it possible to securely erase information previously recorded on an optical recording medium, easily write attached information,
It also has the effect of improving the S/N ratio by controlling the writing light and performing additional writing while reading weak information.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing one embodiment of the present invention. FIG. 2 is a sectional view of the main part of FIG. 1. FIGS. 3(a) and 3(b) are partial sectional views showing one example of another embodiment of the present invention. 1... Optical recording medium 2... Slider (light transmitting means) 5... Optical head 9... Reference information 10.10'... Recording information 11.28... Semiconductor laser 14.14' ...Photodetector 12, 13.29...Condensing lens group 15...Gap 20...Laser diode chip 21...Optical axis 23.23'...(Writing) light number 2 Figure 24...Condensing part 25.37...Reflected light 30...Reading light or more

Claims (1)

[Claims] It is mainly composed of at least one light emitting means, a light transmitting means, a light collecting means, and at least one light detecting means, and the light emitted from the light emitting means is collected by the light collecting means. , through the light transmitting means, the surface of the optical recording medium is irradiated to record information, or the information locally recorded on the optical recording medium is irradiated and the reflected light is read by the light detection means. In the optical input/output device, a gas that moves relatively between the light transmitting means and the surface of the optical recording medium is interposed so that at least 10 μm is formed during the information recording.
An optical input/output device characterized by being installed at the following distance: