TWI233102B - Evaluation method and device for optical recording medium - Google Patents

Abstract

The object of the present invention is to provide a method and device for precisely evaluating the playing durability of the optical recording medium. The solution for the evaluation of the optical recording medium according to the present invention is: recording on the optical recording medium; then, conducting repetitive playing with the playing power in at least three different power levels; measuring the maximum playing times using each playing power with the playing characteristics within an allowable range; using the least square method with the obtained measurement to calculate the linear approximation formula of the relations between the normal exponential log and the playing power; then, substituting the arbitrary playing power into the approximation formula to obtain the playing times; thus, estimating the maximum playing times with the playing characteristics within an allowable range during repetitive playing using the arbitrary playing power.

Description

1233102 V. Description of the invention (1) ~-"Technical field to which the invention belongs" The present invention relates to a method and device for repeated playback durability of optical recording media such as phase change optical recording media. [Knowledgeable technology] In recent years, optical recording media that can record high-density data and erase and rewrite recorded data have attracted much attention. In rewritable optical recording media, those that are phase-change type are recorded by changing the state of the recording layer by the irradiation of the laser beam, and detecting the state of the recording layer accompanying this state change. The reflectance changes to play. The phase-change type optical recording medium has attracted attention because the optical system of the driving device is simpler than that of the optical magnetic recording medium.

When recording material in a phase-change optical recording medium, a high-power (recording power) laser beam is irradiated to raise the temperature of the recording layer to a temperature above the melting point. When the recording power is added, the recording layer is rapidly cooled after melting, and a recording mark of non-t quality is formed. On the other hand, when erasing a recording mark, it is irradiated with a laser beam having a relatively low j rate (erasing power), so that the recording layer is heated to a temperature of 4 or more without reaching a melting point. With the recording mark added with the erasing power, ^ will slowly cool after heating above the crystallization temperature, and return to crystalline. In this way, the phase-change optical recording medium can be rewritable by adjusting a single thunder degree. $ 'Short light In order to achieve recording, and to improve the recording layer surface point (S ρ 〇 t) diameter of the recording layer with high density, the opposite side of the optical system is set, and the laser wave λ / NA is set. Former advancers have recorded the number of openings in the objective lens, which is longer and smaller than the opening wavelength. When the number of lasers for recording and playback is Ν Α,

\\ 326 \ 2d- \ 9l.〇9 \ 91113744.ptd Page 4 1233102 V. Description of the invention (2) [Problems to be solved by the invention] The playback beam originally had a low-power crystalline state, but it was repeated. The result of crystallization is to increase the optical system of the objective lens, which is a large number recorded at high density, that is, the foregoing; when the I / NA is small, it is high, so even if the number of repeated playbacks is large, the durability is decline. In order to improve the performance of such a broadcast, the optical design of the media, or the effect, it is necessary to evaluate the durability of repeated playbacks. For the purpose of ensuring a certain media's 100,000 playbacks, for example, to confirm the recording and playback characteristics. Furthermore, if the playback power is low, it is best to obtain the most suitable playback power within the range that CNR (carrier to noise ratability) can be ensured. In this way, in the past, the optical time and effort have been evaluated. The purpose of the present invention is to The solution is to improve the durability of the recording media. [Methods to solve the problem] The laser beam will not cause the recording ^ to jitter if it is not played back. According to the inventors, ^ media δ has recorded ^ number, borrow If the playback light beam with a short wavelength is irradiated from the opening, the energy density in the laser beam spot will become less jitter or increase, that is, the playback will decrease, and the thermal design of the recording layer must be improved. The playback durability is actually evaluated. Regarding, there is no appropriate accelerated test, so-repeated playback by humans requires actual progress without problems. Due to laser News and reduce the impact of the 1 billion), therefore, necessary to put the player durable power higher. However, at this time, a large number of iterations must be played. The playback durability of recording media needs to be able to accurately evaluate optical methods and devices in a short time.

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V. Description of the invention (3) This object is achieved according to the present invention described in (1) to (6) below. 1) An evaluation method of an optical recording medium, which is a method of evaluating the durability of the playback of the recording medium. The playback power of the recording medium ^ ^ ^ ^ 3 ^ ^ ^ ^ ^ ^ ^ + each has a playback power of i 隹; ^; ^ Rotate and play, determine the case of using repeated playback.] After rewinding—the maximum playback times within the broadcast range. Fanplay characteristics are allowed. 1] Take a hole and place a number of people. According to the measured value, Shows the relationship between the common logarithm of the number of playbacks and the playback power:-The number of people, presumed to be the maximum number of playbacks within the time of the above-mentioned requesting service = sex in the valley, noon. Broadcast-乂: An evaluation method of optical recording media. In order to evaluate the optical ... playback durability, it is an optical recording medium. The media determines the maximum number of playbacks within the target range when using repeated playbacks. The templet is allowed to find the common display value of the number of playbacks. The value of the test value is the least square method. 'Substitute any number of times of play into the aforementioned approximation. Under-produced = To perform any of the aforementioned play: broadcast the enemy (as described above); the maximum value of c power. The aforementioned playback characteristic is an evaluation method of a time-stabilized kinematics 1 recording ... recording medium, wherein: a kind of optical recording medium 4 body motion // error rate. The body-worn durability evaluation device is a mechanism for evaluating optical recording media, and so on; the three types include the following: the optical power of the optical recording media is recorded at different power levels. Into ~ * 4

91113744.ptd Page 6 1233102 V. Description of the invention (4) Repeated playback, the mechanism that determines the maximum number of playbacks within the allowable range when each repeated playback is used; according to the obtained ^, the property is obtained by the least square method A mechanism for displaying a common approximation of the common logarithm of the number of playbacks ^, and the number of times of playback in the approximate expression of any pair and power rate, presumed to be repeated playback of the power before the ^ y J rate is substituted At the time, the playback characteristic is 4 == the mechanism of the maximum value of arbitrary playback. (5) The number of broadcasts born in the "Dry Wall" (5)-an evaluation mechanism of optical recording media, recording with at least 3 different workmen ° recorded media limbs, and measuring the use of each rate Separate advancement :: The mechanism of the maximum number of playbacks within the allowable range: 2 characteristics. The least squares method is used to obtain the display of the measured value of the number of playback times. In the repeated playback of the number of times between powers, the playback 5 is the mechanism that performs the maximum value of the aforementioned arbitrary playback. (6) The playback power in Guxuwei (6) is as described in (4) or (5) above. The evaluation device for the aforementioned playback characteristics is # M # / \ Recording media evaluation device, where [Implementation Mode of the Invention] Beizhucuo Block rate. The evaluation device of the present invention includes a recording mechanism; the optical recording medium is recorded and played at least 3 times. 'Actually measured playback power at each level is used to perform broadcasts within the allowable range. # a. In the case of playback, the mechanism of the maximum number of playbacks of the playback characteristics; and according to the actual measured 91113744.ptd page 7 1233102 V. Description of the invention (5) value, using the least square method to find the common logarithm of the number of playbacks A linear approximation of the relationship with playback power. In the evaluation method of the present invention, first, an optical recording medium is recorded. Then, repeat playback is performed at the playback power of at least 3 different power levels, and the actual measured playback performance is in the case of using each repeated playback. The maximum number of plays in the midday range. Next, the approximate expression of -times is obtained according to the obtained real least squares method to show the relationship between the number of times of playback = use; and the power of playback. This approximation is generally

Y--AlogX + B and B are represented by the evaluation object. X is the number of playbacks, and γ is the constant for the playback power of the media. In the evaluation device of the present invention, there is still a mechanism that can obtain any playback: = like, Y ′ in the formula to obtain the number of playbacks corresponding to the aforementioned arbitrary playback power ⑴. According to this, γ Ruolige's entry in this approximation formula is calculated as follows: the second play should be at the play time of the arbitrary play power described above. The inventors have found that in this way, the arbitrary play power is used repeatedly Condition: The maximum value of the number of playbacks within the above range is almost the same. There is still one in the evaluation device that allows the present invention. An approximate expression, the use of arbitrary playback power, '卩 f, gives the allowable range of the previous time. The maximum number of playback times within t. In this way, if the aforementioned _ times of arbitrary playback power can be obtained, the φ #, similarity 'can be used in the π output playback characteristics within the allowable range

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1233102 V. Description of the invention (6) Maximum play times.

Furthermore, in the evaluation device of the present invention, there is still a mechanism, that is, if X in the foregoing approximate formula is substituted with an arbitrary number of playback times, the aforementioned playback power (Y) corresponding to the arbitrary playback times can be obtained. In this way, if X in the approximate expression is substituted with an arbitrary number of times of playback, the aforementioned playback power (γ) corresponding to the number of times of random playback can be obtained. The present invention uses the approximate formula of the present invention within an arbitrary range, and displays the number of times that the present invention reflects the most within the present invention. The temperature control in the playback device, the recording track using laser light, and the present invention are quasi-different. However, the evaluation of playback performance by people and others is arbitrary, and it is best to install the evaluation of the large broadcast. The number of times that the invention is limited). If you want to play the power, if you try it out, you can find the power in the range of the playback frequency in the most inverse device. The number of playbacks to be considered in the installation. The former also includes the calculation of the pre-ratio (the playback power obtained by playing this 10,000-style test) is almost the same as the above-mentioned case of playback, and there is still a mechanism to obtain the number of the previous one. In the case of repeated playback, the maximum playback power can be estimated. The previous approximation formula can be used to 'calculate the playback characteristics within the allowable range' under arbitrary playback in the recording and playback of optical recording media such as optical disc players. When the temperature rises, the number "2" means that the recordable record is recorded on the recordable track, and the recordable record is recorded (usually a track of type 5 writing. At least 3 power levels are used when the approximate formula is used. (Referred to as test playback power) If there is no special limit, if the power is too low, the test playback power

91113744.ptd Page 9 1233102 V. Description of the invention (7) The maximum number of playbacks within the allowable range of the playback characteristics will become too much, and the effect of shortening the evaluation time of the present invention will be impaired as a result. On the other hand, if the test power is too high, the maximum number of playbacks within the range of f when the playback power is tested will be too small, and the estimation error will easily be large. Therefore, in each case of at least 3 types of test playback power, the maximum number of playbacks within the Guxu range should be between 100 and 100, and it is best to control it between 100 and 5,000. Within 0 times.

Furthermore, the more the number of test playback power, the higher the accuracy of the estimation, but the more the number of test playback power, the more time it will take, and the effect of the present invention shortening the evaluation time is impaired. Therefore, the test playback power is preferably less than five. In the present invention, there are no special restrictions on the playback characteristics of the evaluation index. Generally, the aforementioned playback characteristics are best selected for Clock jitter or Data error rate. The clock jitter is measured by a time interval analyzer, and the "signal jitter (σ)" is obtained. The detection window width is expressed as Tw, which can be different by the formula σ / Tw (%). In the general optical § recorded system, if the clock jitter is below 13%, the signal quality can be said to be no problem. In the present invention, whether or not the playback characteristic is within the allowable range is an evaluation criterion. Therefore, in general, as long as the jitter of the clock is within the allowable range under the optical recording system of ancient parity, it can be used as the evaluation standard. However, it is still effective to use the present invention to estimate the maximum number of playbacks and the maximum playback power when the clock jitter is not substantially increased as the evaluation criterion. At this time, the so-called clock jitter has no substance.

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V. Description of the invention (8) 3) The clock jitter after repeated playback is within ± 0.3% of the initial clock jitter, and it is preferable that the clock jitter does not increase at all from the initial clock jitter. When implementing the evaluation method of the present invention, it is preferable to evaluate the recordable track located on the inner periphery, especially the recordable track on the innermost periphery. For the memorable inner part, repeated execution, compared to the outer memorable part, 执 ^ = The field interval of the field beam is shorter, so the temperature at which the record can be performed is not easy. Perform more rigorous evaluations. 7) The medium with a phase-change recording layer that forms an amorphous recording mark is linear. Ϊ (Recrystallized) # crystalline ^ Recording mark, the crystallization speed of the recording layer must be determined. The faster the linear speed is, the faster the daily date must be. In the case of CAV (Constant Angular e) or 1CAV (Modified CAV), etc., the optical recording system is linear during playback and has a faster perimeter. The crystallization speed of the recording layer is especially effective for the outermost recordable recording. Set the linear speed. Therefore, the track can be recorded at the innermost periphery where the linear velocity is relatively slow. For the linear velocity, the recording layer will crystallize too fast. As a result, it becomes easier to crystallize when the laser beam for playback is irradiated. Therefore, at this time, it is also possible to perform a more rigorous evaluation on the inner peripheral portion, especially the innermost inner recordable track, using the evaluation method of the present invention. Tian You 1 In the recording and playback device of an optical recording medium such as an optical disc drive, the pulse rate increases during recording and playback. Therefore, in consideration of this temperature rise, it is preferable to perform temperature control when evaluating the playback characteristics according to the present invention. The present invention is particularly effective in evaluating the playback durability of a phase-change optical recording medium. It is also applicable to other optical recording media that perform thermal mode (h a t m 0 d e) recording, such as magneto-optical recording media. Moreover, with the present invention

Page 11 嶋 \\ 326 \ 2d- \ 91-09 \ 91113744.ptd 1233102 V. Description of the invention (9) ---- To estimate the above-mentioned maximum number of playbacks and the maximum playback power are not due to media failure (such as The composition of the phase-change recording layer or the thermal design of the medium varies. [Example] A recording disc sample was produced in the following order. First, a support substrate composed of a dish-shaped polymerized carbonic acid with a diameter of 120 mm and a thickness of 1.2 mm was formed by injection molding to form a group (Group) at the same time. The depth of the aforementioned group is set to the optical path length λ / 6 (wavelength λ = 405 nm). The recording track pitch of the convex group recording method is set to 0.3 m. On the group-forming surface of the support substrate, a reflective layer made of A ^ Pc ^ Cu with a thickness of 100 nm was formed by spattering & On this reflective layer, a dielectric layer consisting of αία was formed by a plating method with a thickness of 25 nm, and a composition (atomic ratio) was formed by a plating method.

Ag. 51 nG. 5 Sb76 Te18Ge5 recording layer with a thickness of 2 nm. On this recording layer, a dielectric layer having a thickness of 135 nm was formed by ZnS (80 mol%)-SiO2 (20 mol%) by a plating method. On this recording layer, a light-transmitting layer having a thickness of 100 was formed by spin-coating and curing a UV-curable resin. After the recording layer of the above sample was evaluated with a degaussing machine (Bulk Eraser) after initializing (crystallization), the above sample was placed on an optical recording medium under the following conditions 〃 Laser wavelength: 405nm Number of openings: 0.8 5 Recording line Speed: 6. 5 m / s 1233102

5 Recorded signal: (1_7) RLL (shortest mark length 0 · 173 // m) Enter 4 for recording and playback and measure jitter. This jitter is the time when the guanidine will be hungry and scientific. : Jitter is used as the initial jitter. The playback power at this time is the value shown in Table 丨 Test. Then use this test playback power to repeatedly play and measure the jitter, and find out the maximum number of times that the jitter will not increase. The maximum number of playbacks measured by this number of people is shown in Table 1. In addition, the relationship between the number of plays and the jitter during these measurements is shown in Fig. 1. The pr shown in Figure 1 is the experimental playback power. [Table 1] Table 1 j-type test playback power (mW) measured maximum playback times 0. 40 1650 0. 42 207 0. 43 23 _ Second, the playback power shown in Table 1 and the measured maximum when using this playback power The number of times of play can be obtained by the least square method. Y = -0. 01671〇gX + 0 · 4537 In this approximation formula, X is the maximum value of the number of playbacks when the jitter is not assumed to increase with the playback power γ. Or it can be said that γ is the maximum value of the playback power when jitter is not repeated for X times. The relationship between the number of playbacks X and the playback power γ is shown in Figure 2. Fig. 2 also shows the measurement results shown in Table 1. From the above approximation formula, the maximum value of the playback power that does not increase the jitter is assumed to be Y when X = 10,000, that is, when it is repeatedly played 10,000 times.

\\ 326 \ 2d- \ 91-09 \ 91113744.pid Page 13 1233102 V. Description of the invention (11) At the same time, X = 1 0 0, 0 0 0 [Table 2] Y is obtained. This special result is shown in Table 2. Table 2 assumes the maximum number of playbacks to estimate the maximum playback power "in ΉΠ 10,000 0.39 100,000 ______ 0. 37 Secondly, for the above samples, the playback power shown in Table 3 was actually performed 10, 0 0 0 times and 1 0 0, 0 0 0 times repeated playback, and the jitter after repeated playback was measured. The results are shown in Table 3. [Table 3] Table 3 Playback power (mW) 1 0, 0 0 0 playback jitter (%) 1 0 0, 0 0 0 times the jitter of i (%) 0. 34 7. 9 7 · 9 0. 36 7. 9 7. 9 0. 37-8. 0 0. 38 7. 9 8. 6 0. 39 7. 9 — 0. 40 8. 7 The effect of the present invention can be understood by comparing Table 2 and Table 3. As shown in Table 2, when repeated playback is performed 10,000 times, it is estimated The maximum value of playback power that does not increase jitter is 0.39mW. On the other hand, as shown in Table 3, when repeated playback is performed 10,000 times at a playback power of 0.39mW, the jitter does not increase. Large, but when the playback power is slightly increased to 0.4 mW, the jitter of repeated playback is

91113744.ptd Page 14 1233102 V. Description of the invention (12) That is a substantial increase. In addition, the same is true when the number of repeated playbacks is 100, 000, and the estimated value according to the present invention is approximately the same as the actual measured value. [Effect of the invention] According to the present invention, the playback durability of the optical recording medium can be accurately evaluated in a short time. By using the evaluation method and device of the present invention, it is possible to know its maximum playback power within a short period of time within the range where the necessary playback durability can be ensured. Therefore, according to the present invention, it is easy to design an optical recording system capable of obtaining excellent playback durability and high CNR.

91113744.ptd Page 15 1233102 Brief description of the figure Figure 1 is a graph showing the relationship between the number of playbacks and jitter. Fig. 2 is a graph showing the relationship between the maximum value of the number of playback times X and the playback power Y when it is assumed that the playback power Y is used for repeated playback.

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Claims (1)

1233102 Sixth, the release of the request for close push in the c, the release of the close push for method C broadcast L patent application 1 · An evaluation method of an optical recording medium is a method for evaluating the durability of the optical recording medium. It records the optical recording medium "= repeated playback at each of the playback powers of at least 3 different power levels. In the case of using separate repeated playback, the maximum number of playbacks within the range of ☆, according to the measured value obtained, the relationship between the common logarithm of the number of playbacks and the playback power is displayed in the least two out. The playback obtained by substituting arbitrary playback power into the above approximate formula = is the maximum number of playbacks within the allowable range of playback during the repeated playback of the aforementioned arbitrary playback power. The broadcast evaluation party * 'is for evaluating optical recording media and even J3 playback power of different power levels is measured. In the case of using repeated playback, determine the maximum number of playbacks within the broadcast range. According to the obtained maximum = similarity, between the number and the playback power. The relationship of one time will be Rong I. Li ik any number of times of play into the foregoing is almost the same as the above-mentioned arbitrary play times Lu Wu consumption within the playback power It is most like the item i or 2 of the scope of the patent application, where the aforementioned playback characteristics are a device for evaluating the durability of an optical recording medium, which includes the playback power obtained in the formula 0, and the playback characteristics are large during repeated playback. Evaluation of optical recording media ^ Jitter or data error rate ^ Set 'to evaluate optical recording media