JPH0287328A - Optical recorder - Google Patents

Abstract

PURPOSE:To attain proper recording over a wide temperature range by using a temperature sensing element provided on a photodetector substrate so as the detect a temperature near a head amplifier, thereby controlling a delay of a recording data in response to the detected temperature. CONSTITUTION:The delaying amount of a recording data variable delay circuit 10 is controlled in response to a temperature detection signal from a temperature sensing element 4 provided on a photodetector substrate with an optical sensing element 1 arranged thereupon. Thus, the delay time of the variable delay circuit 10 is controlled by a delay control circuit 20 in response to a temperature sensing signal from the temperature sensing element 4, for example, mounted on the photodetector substrate to cancel the change in the delay time of a regenerative signal due to temperature. Thus, the deviation of the recording position on an optical recording medium such as an optical disk due to temperature from a proper position is compensated and normal use over a wide temperature range is attained.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an optical recording device for recording data on an optical recording medium, and particularly for recording data on an optical recording medium such as an optical disk into which clock information has been written in advance. The present invention relates to an optical recording device for recording.

[Summary of the invention]

The present invention relates to an optical recording device that reproduces clock information written in advance from an optical recording medium such as an optical disk via a photodetector element, and records recorded data synchronized with the reproduced clock information, on a photodetector element substrate. By installing a temperature detection element such as a thermistor on the top and controlling the amount of delay of recorded data according to the temperature detection signal, changes in the amount of delay in the analog circuit system due to temperature changes can be canceled.
This is to prevent the recording position from shifting due to temperature changes.

[Conventional technology]

In an optical disk recording device for recording desired data on an optical recording medium on which clock information has been written in advance, for example, an optical disk of the so-called Sanfi Jread servo form, clock bits are reproduced using a photodetecting element such as a photodiode. The recorded data is synchronized with the reproduced clock signal obtained by the above process, and this recorded data is delayed by a predetermined period of time before being recorded.

In other words, there is a time lag between each bit of the reproduced clock signal and each bit position on the optical disk, mainly due to analog signal delays in the playback head amplifier, etc., but this difference is corrected. Therefore, it is necessary to make the recording data precede the bit position of the reproduced clock. In this case, adjustment in bit units (chance clock units) is performed by changing the focus numbers using a timing generator, etc., and generating recording data.
The deviation below the bit width is adjusted using a delay line, etc. By leading the recording data in this way, the above deviation is canceled and the actual data recording position is adjusted properly with respect to the pre-written clock. It has been corrected so that it is in the correct position.

[Problem to be solved by the invention]

However, the reproducing system's henode amplifier, etc. has temperature characteristics, and the analog signal delay amount changes depending on the temperature. Therefore, even if the recording position is adjusted as described above at a predetermined temperature, the temperature will change. This may cause the recording position to deviate from the proper position.

Especially for optical recording devices intended for special purposes, such as use in polar regions, aircraft, and spacecraft, the temperature range is wide from several tens of degrees below zero (for example, -50°C to 50'C).
However, when such a wide range of temperature changes occurs, the deviation from the above-mentioned proper recording position becomes large, which can cause focus errors when reproducing data, for example. It becomes.

The present invention has been made in view of these circumstances,
It is an object of the present invention to provide an optical recording device that can correct the deviation of the recording position due to variations in the amount of delay of a reproduction amplifier system in response to temperature changes, and can be used normally over a wide temperature range.

[Means to solve the problem]

In order to solve the above-mentioned problems, an optical recording device according to the present invention reproduces clock information from an optical recording medium into which clock information has been recorded in advance by a photodetecting element, and performs a synchronization with this reproduced clock signal. An optical recording device that records recorded data on the optical recording medium, comprising: a temperature detection element provided on a photodetector substrate on which a photodetection element is disposed; a variable delay circuit for delaying the recorded data; It is characterized by comprising a delay amount control circuit that controls the delay amount of the variable delay circuit in accordance with the temperature detection signal from the temperature detection element.

[For production]

Since the amount of delay of recorded data is controlled according to the temperature detection signal from a temperature detection element such as a thermistor provided on the photodetector board, the recording position on the optical recording medium such as an optical Y disk depends on the temperature. It is possible to compensate for deviations from the proper position.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG.

In FIG. 1, a photodetector element (photodetector) 1 consisting of a photodiode or the like is used to detect signal reading light that is reflected light or transmitted light from an optical disk (including a magneto-optical disk) on which servo information is written in advance. is provided on a so-called photodetector board, and the photodetector element l shown in FIG. There is. The photodetection (current) output from each of the four divided light receiving sections IA, IB, and IC1ID of this photodetecting element 1 is converted into a voltage signal by current-voltage conversion amplifiers 2A, 2B, 2C, and 2D, respectively, and then A so-called matrix amplifier 3 performs addition, subtraction processing, etc., and outputs it to a PLL circuit 6 as a clock information reproduction signal.
is being sent to. These current-voltage conversion amplifiers 2A,
A so-called head amplifier consisting of 2B, 2C12D and matrix amplifier 3 is provided on the photodetector board.

Here, in a so-called sampled servo format optical disc, as shown in FIG.
, P1. PC is written. That is, pitches pm and p are formed on different sides of the 3.4th bit trunk center line (-dotted chain line) in this servo area, and the n-3rd bit (n is 16, for example). A pit PC is recorded and formed on the center line of the trunk. When the laser beam spot LBS is relatively moved and scanned along this track in the direction of the arrow, the reflected laser beam is detected by the photodetecting element 1 and the so-called head amplifiers (amplifiers 2A to 2D and 3) are detected. For example, the focus detection pulse in the reproduced signal obtained through S
It becomes like A=SI+SC. At this time, each viat PA, P1. The time shift amount ΔT1 of the pit detection pulse SA+Sl+SC with respect to the recording position of the PC is the analog signal delay time due to the head amplifier.

The PLL circuit 6 outputs a channel clock reproduction signal as shown in FIG. 2C based on the pit detection pulses sA+Sl+SC and the like shown in FIG. 2B, and sends it to the recording data generation circuit 7. Here, when the channel clock period is t, the recording data generation circuit 7 generates recording data that is synchronized with the channel clock reproduction signal C and precedes the time lag star ΔT by a longer time kl. (Fig. 2D) is generated. This lead time k
k of t is an integer and has a value that satisfies (k-1)t≦ΔT+<kt. Corresponding to the focus recorded portion of this recorded data, a recording pulse q as shown in Fig. 2 is generated.
, is obtained, and in order to record it at the proper recording position on the optical disk, the variable delay circuit IO is used to delay the predetermined time ΔT.
It is delayed by 2.

However, the data bit p11 on the actual optical disk is recorded at a position delayed by a time ΔT3, which is the sum of the laser diode modulation delay time and the time required for recording on the medium, as shown in an enlarged view in FIG. .

That is, the time required for sending the recording data from the variable delay circuit 10 to the laser light source drive circuit 8 to drive the laser light source, for example, the laser diode 9, and modulating the brightness of the laser, and the time required for the laser beam to be irradiated onto the optical disk. The sum of the time required for the pit p to be actually recorded is the delay time ΔT. The relationship between these delay times ΔTI+ΔTiΔT is expressed as ΔT+−kt+ΔT2+ΔT,=0.

If the temperature changes, the head amplifier (amplifier 2A ~
The delay time ΔT1 of the reproduced signal due to analog signal delay etc. in 2D and 3) changes.

As an actual example, the delay time T is 190 at room temperature.
ns (nanoseconds), of which the analog signal delay time due to the head amplifier is 90 ns, and the change in delay time due to temperature is ±1 Ons. Here, the phase margin considering the error rate is about ±25ns,
Considering circuit variations and other margins, the variation in delay time ±Ions cannot be ignored.

Therefore, one F
A temperature detection element 4 such as a thermistor is provided on the photodetector substrate, and a variable delay circuit I is controlled by a delay amount control circuit 20 in response to a temperature detection signal from the temperature detection element 4.
By controlling the delay time ΔT2 of O, changes in the delay time ΔT due to temperature are offset.

Here, as a specific example of the variable delay circuit 10, a delay circuit 11 such as a multi-output delay line that outputs signals delayed by different delay times from a plurality of output terminals.
and one of the plurality of delayed outputs from this delay circuit 11.
A selector 12 is used which selects and outputs one of the two temperatures, and the delay amount control circuit 20 controls switching of the selector 12 according to the detected temperature. Further, as a specific example of the delay amount control circuit 20, the temperature detection element 4
An analog/digital (A/D) converter 21 that converts the temperature detection analog signal from the A/D converter 21 into a digital signal, and an appropriate delay time selection according to the temperature data from the A/D converter 21. A ROM (read only memory) table 22 that outputs selector switching data is used, and this can be realized by reusing, for example, a part of the CPU system provided in the optical disk device. The ROM table 22 outputs selector switching data so that the optimum delay time is selected for the human temperature data based on the relationship (measured data) between the temperature of the head amplifier, etc. and the delay time. .

In this way, in order to match the data writing position when writing recorded data in an optical disk recording device to the reference channel clock phase according to the clock information recorded in advance on the disk surface, analog Changes in the amount of delay such as signal delay time are adjusted using a variable delay circuit, which allows accurate writing of recorded data under a wide range of temperature conditions and improves the error rate when reading data from the reproduced signal. can.

It should be noted that the present invention is not limited to the above-mentioned embodiments. For example, the variable delay circuit and the delay amount control circuit are not limited to the illustrated example, and a circuit that changes the delay time itself may be used.

〔Effect of the invention〕

According to the optical recording device according to the present invention, the temperature near the head amplifier is detected using a temperature detection element such as a thermistor provided on the photodetector board, and the amount of delay of recorded data is controlled according to the detected temperature. By doing so, it is possible to suppress changes in the signal delay amount of the head amplifier due to temperature, and to ensure that the actual recording of data is performed at the reference clock position according to the clock information written in advance on the recording medium, regardless of temperature changes. This makes it possible to perform proper recording over a wide temperature range.

[Brief explanation of drawings]

FIG. 1 is a block circuit diagram showing a schematic circuit configuration of a head amplifier device of an optical disc playback device according to an embodiment of the present invention, FIG. 2 is a time chart for explaining the operation of the embodiment, and FIG. FIG. 3 is a diagram for explaining the delay when actually recording and forming data bits. 1...Photodetection elements 2A to 2D...Current-voltage conversion amplifier 4.
...Temperature detection element (thermistor) 10...
・Variable delay circuit 20...Delay amount control circuit

Claims (1)

[Scope of Claims] Optical recording in which clock information is reproduced from an optical recording medium in which clock information is written in advance by a photodetection element, and recorded data synchronized with the reproduced clock signal is recorded on the optical recording medium. In the apparatus, a temperature detection element provided on a photodetector substrate on which a photodetection element is arranged; a variable delay circuit for delaying the recorded data; 1. An optical recording device comprising: a delay amount control circuit that controls a delay amount of a delay circuit.