JPS6016013B2 - Signal recording method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a recording method that performs recording by scanning a recording medium with light.

Technical Background In a method for optical high-density recording, the drive signal voltage applied to a light intensity modulator is proportional to the modulated light intensity, and the modulated light intensity is sufficient for temporal changes in the drive signal voltage. Even if the drive signal voltage is constant, depending on the recording conditions, the recording amplitude of the recording pattern on the recording medium will not be constant for reasons described later.

This is true, for example, when recording a recording pattern obtained on a silver halide film using a reproduction light spot that can be ignored with respect to the recording wavelength, photoelectrically converting the transmitted light and obtaining density changes as electrical signals. Since the amplitude is not constant, the amplitude of the electrical signal changes, and the recording pattern on the recording medium is reproduced incorrectly, or in extreme cases, it becomes undetectable.
Purpose Therefore, the present invention is to correct in advance the deterioration of signal amplitude during reproduction that occurs when the recording amplitude of a recording pattern on a recording medium is constant or when the reproduction light spot is finite. This can be achieved by correcting the drive signal voltage when modulating the light intensity in relation to the recording wavelength.

- The details of the present invention will be explained below with reference to the drawings.

Figure 1 shows a recording method using laser light as one of the optical recording methods, where 1-1 is a laser light source, 1-21
1-3 is a laser beam irradiated by the laser light source with a constant unmodulated light intensity; 1-3 is a well-known KDP, A;
An optical modulator that uses electro-optic effects or electro-acoustic effects such as DP.

1-22 is a laser beam whose light intensity is modulated, 1-4 is a beam expander for expanding the diameter of 1-22 in the laser light beam, 1-23 is an expanded laser light beam, and 1-5 is a beam expander for expanding the diameter of light beam 1-22. A focused optical system is arranged to image the laser light east 1-23 and form a minute light spot, and 1-24 is a focused laser light east.

Reference numerals 1-25 denote a light spot formed by this focusing optical system, and 1-6 denotes a recording medium, which will be explained below by taking a silver halide film as an example.

1-7 is an arrow indicating the moving direction of the recording medium, 1-8 is an input terminal for recording signal voltage, 1-9 is a known PFM modulator used in VTRs, etc., and 1-10 is a PFM modulator. This is a power amplifier for the recorded signal voltage.

Therefore, the recording signal voltage input to input terminals 1-8 is P
Power amplifier 1 subjected to PFM modulation by FM modulator 1-9
-1 The power output for driving the optical modulator 1-3 is amplified, becomes a driving signal voltage, and is input to the optical modulator 1-3. A laser beam 1-21 from a laser light source 1-1 is intensity-modulated by an optical modulator 1-3 and becomes a laser beam 1-22. The diameter of the laser beam east 1-22 is expanded by a beam expander 1-4. As is well known, the function of the beam expander 1-4 is that in order to obtain a minute light spot, the wavelength of the laser beam and the diameter of the light beam entering the focusing optical system 1-5 are related. This is because if the focal length of the east optical system is constant, the larger the diameter of the incident light beam, the smaller the obtained light spot. The laser light beam 1-23 is imaged as a minute spot 1-25 on a recording medium 1-6 moving in the direction of arrows 1-7 by a focusing optical system 1-5, and recording is performed on the recording medium. . In the following explanation, the drive signal voltage of the optical modulators 1-3 and the light intensity of the laser beam which has been optically modulated by the drive signal are photoelectrically converted by a photoelectric converter such as a photomultiplier tube. It is assumed that the electrical signals are similar. In the above assumption,
As is well known, in an optical modulator that utilizes the electro-optic effect, the relationship between the drive signal voltage Ein and the optical intensity lout of the laser beam is expressed as loutQ Sin2Ein, and this nonlinearity can be avoided by correcting the drive signal voltage in advance or by modulating the laser beam. One possible method is to use the electric signal obtained by photoelectrically converting the laser beam generated by the laser beam and correct it by negative feedback.
It is clear that this assumption is not inappropriate for explaining the gist of the present invention. Next, a perspective view of FIG. 2-1 shows the exposure state of the recording medium 1-6 in such a case. In addition, in FIG. 2-1, the point shown as the minute light spot 1-25 in FIG. 1 is enlarged and drawn.
Also, for the sake of simplicity, it is assumed that the irradiance of the light within this light spot is uniform and lo.

At the current time t2, the recording body 1- of the light spot 1-25
6, the center of the light spot 1-25 is B, and the points that intersect with the outer periphery of the spots 1-25 on the line segment 1-7 passing through this point B and indicating the direction of movement are 2-1, respectively. Let them be A and C as shown. (Based on the diameter of the light spot.) Now the consignment body 1-
If the moving speed of 6 is v, and the time it takes the recording medium to move a distance equal to the diameter envelope 2 of the light spot 1-25 is ↑phantom,
At time t2, the drive signal voltage 2 is applied to the optical modulators 1-3.
Assume that the Emax is 2 so that the laser beam can pass through (
2-3), consider the case where the duration of Emax2 is 3, that is, the exposure time is t<2. Generally, the amount of exposure P applied to the recording medium 1-6 is expressed as P:lot, which is the sum of the irradiance lo and the exposure time t. Therefore, the point to the left of point A is lo: 0, so P=0, and point C is t
=7th, so P=? 21, point B skin = cow, so P: is 10.

That is, the exposure amount at each point on the line segment AC is
2. It is given by the product of the time taken for the light spot 1-25 to pass through that point and L, and this situation is shown in FIG. 2-2. In addition, the machine axis in Figure 2-2 is the same as the extension line of line segment AC, and the unit is length, and A'B
Each point of 'C'... is shown in Figure 211 A, B, C...
This indicates the position corresponding to . Next, after time t has elapsed, the drive signal voltage becomes Emjn2 at time et al., the laser beam is cut off, and the exposure is stopped. Then, point ○ on the recording body is at time t, and point A on the recording body is at time t. It has reached the same level as the position where it was, and point E, which is further away from point D, is at the same level as the position where point C was at the time.

It is clear that the amount of exposure received by each point between points D and E follows the course of exposure opposite to that of each point between points A and C, and therefore, as shown in FIG. The change in the exposure state during E' is symmetrical to that during A'0.
Here, line segment AC=d2=A'C', line segment CD=V et al.2-
, line segment DE = also = D'〇, line segment AD = VT foundation = A'〇, line segment A'8 = Vt220. Alternatively, even if the completion is performed at infinite speed, at that point there will be a portion where the exposure amount changes by one point in the direction of movement of the recording medium with respect to the center of the light spot.

Next, FIG. 3 shows a recording state using a drive signal voltage consisting of a continuous pulse train with a constant repetition period.

In the following description, it is assumed that recording is performed in a region where the recording density D of the recording medium, that is, the silver halide film, is linearly proportional to the product of the irradiance of the light spot and the exposure time, that is, the amount of exposure. FIG. 3-1 shows the temporal change of the drive signal voltage E3 input to the optical modulator, which has a repetition period T, and has a waveform with a symmetrical light irradiation time tp, and the drive signal It is assumed that the maximum value of is Emax and the minimum value is Emin3.

Figure 3-2 shows the temporal change in the radiant intensity of the laser beam that has passed through the optical modulator and is modulated, assuming that the drive signal voltage and the modulated laser beam radiant intensity are proportional as described above. Since each corresponds to Emax3, lmax group min3
is shown as lmin3. Figure 3-3 shows the amount of exposure given to the recording medium by the laser light.
The horizontal axis of the coordinates corresponds to Yokoto in Figures 3-1 and 3-2, that is, time, and is indicated by a distance 1 connected by the relational expression 1=vt. In the figure, the exposure corresponding to the maximum value of the exposure amount is given as 1,=vtp1, where the distance given to the recording medium is 1, and the moving speed is v. (Here, d3 is the diameter of the light spot, and it is assumed that there is a relationship of = tp2.) Based on the above-mentioned assumption of exposure amount and density, how the density recorded on the recording medium varies over distance. As shown in FIG. 3-4, the relationship is similar to that in FIG. 3-3. Next, when the pulse width tp is different from tp4, tp42, tp43 (however, it is a symmetrical rectangular wave and the period is L, , L2, T wax) (T4
,>T delivery>T43) will be explained with reference to FIG. Note that the relationship between the horizontal axes in FIG. 4 is the same as that in FIG. 3, and since the drive signal voltage and the light radiation intensity are similar, the diagram showing the radiation intensity is omitted. In Figure 4-1, 4-・a is tp mountain》 etc., 4-・b is tp42=ki,
4-IC fitting 43<> and the like are shown respectively. In the case of 4-la, as is clear from the explanation of FIG. 3, the exposure amount changes as shown in FIG. 4-2, 4-2a, and the resulting density change on the recording medium is as shown in FIG. It becomes 3a. In the case of 1st p42i, the exposure amount is 4th -
As shown in Fig. 2-4-2b, the flat portion disappears, but the maximum value of the exposure amount is the same value Pmax4 as in Fig. 4-2-2a,
The density change on the recording medium obtained by this is shown in Figure 4-3.
It is clear that the result is as shown in -3b. tp43《
In such cases, the rise and fall of the exposure amount is uniquely determined by the moving speed v of the recording medium, the diameter d3 of the light spot, and the amount of change in the exposure amount (Pmax4-Pmin4). 2 As shown in Fig. 4-2c, at the time when the drive signal voltage corresponds to Emax4, the exposure amount power Pm
Before reaching ax4, Pm is similarly influenced by the falling point of time corresponding to the next drive signal voltage Emin4.
Before reaching in4, it will be affected by the rising point of time corresponding to the next drive signal voltage Emax4, and as a result, the exposure amount will be reduced compared to the case of FIGS. 4-2a and 4-2b. That will happen. In this case, the density change on the recording medium is as shown in Fig. 4-3c, Pmax4 and Pm
It is clear that a recording density corresponding to in4 cannot be obtained. The above explanation is for the case where the drive signal voltage is constant, but from a different perspective, how to make the amount of change in recording density on the recording medium constant even if the pulse repetition period T changes? Consider what kind of drive signal voltage should be applied.

Figure 5-1 shows that when the recording wavelength on the recording medium is 0, the distance of the sum of the distance with high density and the distance with low density is M, L52, L5.
3. An ideal recording pattern of density change is shown when the distances between high and low density are equal. However, even if the rise and fall of the drive signal voltage were infinitely fast, it would be impossible to obtain the recording pattern shown in Figure 5-1 because the diameter of the light spot is finite. The following is an example of the case where the maximum and minimum values of the density obtained in the recording pattern that can be realized when the diameter is equal to 5-1b as shown in the figure are constant regardless of the recording wavelength. Shown in Figures 5-2. Here, in Fig. 5-2c, due to the above-mentioned restriction on the diameter of the light spot and the condition of constant density, the positional gradient of the density is steep, and in the case of sphere: gable, compared to Fig. 5-2b At that time, the slope will be 1.5 times. Figure 5-3 shows the temporal change in the drive signal voltage necessary to provide such exposure, since Figure 5-2 corresponds to the temporal change in exposure amount. , 5-3b correspond to 4-la and 4-lb, respectively. In addition, in FIG. 5-3, the relationship with FIG. 5-1c is connected by 1 spot = vtp spot, and the same is true for tp52 and t technique. In 5-3c, the drive signal voltage is increased in order to make the temporal change in exposure amount, that is, the slope, more rapid than in the first two, as described above.

In other words, if Figure 5-3'Koshi, Te, Imako 2 = 53 in total (snake = cloud tp53), the slope of 5-2c is 5-2a, 5-
Compared to the case of 2b, it is 3/2 times, (for this reason, the forehead slope at 5-2c = Pmax5MPmin5tp
53 father relationship max5-Pmin5)), therefore, the drive signal voltage E and the illusion p52 are 3'2(Emax5-Emin
It is clear that 5) is necessary.

As described above, in order to keep the recording density on the recording medium constant regardless of the cycle of the drive signal voltage, it is possible to achieve this by correcting the drive signal voltage in relation to its repetition cycle. judge.

However, although the above explanation deals with a steady state, that is, a case where the periods of the drive signal voltages are different, it does not take into account changes in the temporal period, that is, transient states. The first gist of the present invention is, of course, to perform the above-mentioned correction, but also to form a desired recording pattern on a recording medium when the period changes over time, that is, in a transient state, as described below. A more detailed explanation will be given below with reference to FIG. 6.

FIG. 6 shows a "desirable recording pattern" on a recording medium based on a recording pattern of an arbitrary recording wavelength.

Here, the "desirable recording pattern" means that the recording density is the maximum value Dmax61 and the minimum value Dmin61 with respect to the recording length, that is, in FIG.
, and changes from Dmin61 to Dma
This means that the density change at the end reaching x61 or vice versa is infinitely steep. In some cases,
The term "desired recording pattern" may also mean a recording pattern that is intentionally created, for example, a recording in which the density change at the edge is not infinitely steep but has a constant slope.

However, in these cases as well, the "desirable recording pattern" defined in this explanation is changed to a "less desirable recording pattern," so it is important for the present invention that the following explanation is based on the "desirable recording pattern." It does not impose any restrictions on the subject matter. Figure 6-2 is tentatively shown in Figure 6-2.
1 Scanning the recording pattern made as shown in the figure using a reproduction light spot having a finite Sekiguchi and uniform irradiance,
This figure shows an outline of the reproduced output voltage from a photoelectric converter obtained when a change in concentration is photoelectrically converted.

(The machine axis t is a time axis that is related to the scanning speed Vs during reproduction by 1=Vst, and if we consider that Vs is equal to the moving speed V of the recording medium in Fig. 3, Figs. 3 and 4 , the time axes of FIGS. 5 and 6 are the same.) Here, in FIG. 6-2, it is assumed that the reproduction output voltage is corrected to be linear with respect to the concentration, and that the time t side t62.・・・・・・
t6 and o correspond to the time when the center of the reproduction light spot passes through the position where the density change occurred on the recording medium, and the diameter of the reproduction light spot is equal to the recording length 163 on the recording medium. ing. In Fig. 6-1, the reproduction output voltage for the part where the recording length of the high density part is 16, 162, the length of one library, is flat at Emax61 or Emjn61 as shown in Fig. 6-2. have.

Further, the reproduction output voltages corresponding to recording lengths of 163 and 168 do not have a flat portion, but have a peak reaching Emax61 or Emin61. However, 164,165,1
The reproduction output voltage corresponding to Europe, 167 cannot reach Emax61 or Emin61, as can be inferred from the 4-lc, 4-2c, and 4-3c during recording, and the fluctuation of the reproduction output voltage decreases. The thing is clear.

On the other hand, in the case of a recording pattern as shown in Figure 6-1, for example, if this recording pattern corresponds to an FM modulation signal such as that known in VTRs, the modulation signal, that is, the original information, is converted into a change in frequency. 16 on the record,
, 162, . . . , 169 are related to the original information, and therefore, in FIG. 6-2, the recording lengths t6. It is considered that the original information is related to the reproduced output voltage at each time point k and o.

In addition, in the NR21 method or PE method used when recording digital data on a magnetic tape, magnetic cassette recorder, etc., the digital data, that is, the original information is the maximum and minimum density value Dmax61,D in Figure 6-1.
min61, 16. on the recording body.・・・・・・１
Recorded length of spots and density change position No. 6-3 Diagram 62,
In Figure 6-2, these are respectively Em
ax61, Emin61, time, etc. It is thought that it is related to the reproduction output voltage at the skin.

The above-mentioned time points t6,...t6,.

The importance of the reproduction output voltage, the oscillation value of the reproduction output pressure, etc. is F
Needless to say, this applies not only to the recording of M-modulated signals or digital data signals, but also to the recording of all kinds of information. In the case of digital recording, in order to identify 0 and 1 in a digital signal, there are medium densities that are allowed for each of 0 and 1, and therefore, the density does not necessarily have to be maximum or minimum. 6th
Considering the above-mentioned points in Figure 3, in order to make wide use of the recordable density range of the recording medium, in this case silver halide film, the maximum value of the recording density should be set close to the maximum value of the possible range, with a maximum of 4. An example of a desirable recording pattern that is possible under the constraints of keeping the value constant regardless of the recording length and recording with a light spot having a finite diameter will be shown below.

Points to note in Figure 6-3 are times t64, t66, and k7.
, 8, the slope of the density change at each position on the recording medium corresponding to 8 must be 4/3 times as large as that in FIG. 612.

FIG. 6-4 shows the drive signal voltage E of the optical modulator that is desirable for obtaining a recording pattern having the density change shown in FIG. 6-3.

Particular attention should be paid here to the rising time t6, . . . of the drive signal voltage corresponding to the time k4. and the same rise time point t6,2 in the time point t muscle, and the time point t skin shown in Figure 6-4 is delayed by time t6,3 from time point t64, and time point t6,2 is 762 times ahead of time point 9. be. Now consider the case in which a light spot with a diameter d6 equal to one recording length moves along the machine axis in the direction of the arrow on the coordinate axis in FIG. 613, and recording is performed. When the density changes at the positions corresponding to time points et al. in Fig. 6-3, the distance between the density rising position * and the position where the density becomes constant *3 is equal to the diameter of the light spot, and therefore the light spot moves the coordinate axis and when the center of the light spot is located at position x62, the 6-4
As shown in the figure, the drive signal voltage is changed from Emin62 to Emax.
By changing it to 62, it is at the position shown in the figure 6-3. From then on, recording up to &3 is performed.

The same applies to recording near position x64. However, at x65, which corresponds to time 4, the concentration gradient needs to be 4/3 times that at position &2, pine 4, etc., as described above, so the center of the light spot is at position 5, that is, time t64.
The drive signal voltage is changed from Emax62 to Emin63.
If this is changed, the density slope will certainly be 4/needle sound, but the position at which the density change starts will be *5', and the recording pattern as shown in FIG. 6-3 will not be obtained. The way to prevent such a recording pattern is to increase the drive signal voltage to Emax62.
The time required for the light spot to move from position Ume 5' to Matsu 5'' to change to Emin63 = raw 5
VS can be achieved by delaying the distance by 5.

That is, time points H, . This is the point at which the drive signal voltage is changed in order to perform the desired recording shown in Figure 6-3. Furthermore, the method for obtaining the density gradient at position b66 can be considered in the same manner as described above.
Fig. 6-5 shows a recording pattern based on the corrected drive signal voltage shown in Fig. 6-4, and Fig. 6-6 shows a recording pattern based on the uncorrected drive signal voltage, showing that the correction is effective. There is. Furthermore, the recording pattern in the section of position 6 and x in Fig. 6-5 is further shown in Figs. 6-7 and 6-8.
This will be explained using figures. In Figures 6-7 and 6-8, the axis and vertical axis are enlarged twice, and the position at the time of entry is 6th.
This is the same as in Figures 1-1 to 6-6. From Emax63 of the drive signal voltage at time k3 in FIG. 6-7, Em
The change to in63 can be used as is to obtain the concentration gradient at the hawk tower 8 in Figure 6-8, but if the next drive signal voltage change point is set to [69], the obtained concentration gradient is The result is as shown by the dotted line 61 in FIG. 6-8.
In such a state, the recording density is set to vary around the line 62, but the position where the dotted line 61 passes through the line 62 is *7', which causes an error. If the change point of the drive signal voltage is advanced from point t to point k,2, this error can be corrected as shown by the solid line 63 in Fig. 6-8. overlap, resulting in a flat portion as shown in Figure 6-8, which does not reach Dmin61, but this is not a particularly problematic amount. To summarize the above explanation, if the recording length ls on the recording medium is ls>d with respect to the optical spot d used for recording, the drive signal voltage does not need to be corrected. In particular, when the recording wavelength ls changes transiently, it is necessary to change the amount of change in the drive signal voltage and the time point at which the drive signal voltage is changed (hereinafter referred to as the correction time point). Particularly in the latter case, the correction time point is determined based on the state of the drive signal voltage past the correction time, that is, the duration of Emax or Emin, and the state of the drive signal voltage that will occur next, that is, Emax or Emin.
It will be determined by the duration of the period. FIG. 7 shows a configuration diagram as a specific embodiment of the present invention.

In the following description, the recording conditions, such as the moving speed of the recording medium, the diameter of the light spot, and the like, are all the same as those used in the description of FIG. 6, such as that the recording medium is a silver halide film. 7
151 is an input terminal for the recording signal to be corrected, 7-2 is a NOR circuit, 7-3 is a triangular wave generator consisting of a known integrating circuit, etc. 7-4 is a sampling circuit with a known circuit configuration. 7-5 is a sampling pulse generator, for example, a trigger-type blocking oscillator, etc. 7-6 is an inverting multiplier, which is a normal multiplier in which the input and output maintain a linear relationship and are in antiphase. The device 7-7 is a NOR circuit,
7-8 is a triangular wave generator similar to 7-3, 7-9 is 7-4
7-10 is a sampling pulse generator similar to 7-5.

7-11 is a discriminator, for example, a normal clipper using a diode, etc. 7-12, 7-14 are normal intensifiers, 7-13 are intensifiers, such as a Schmidt circuit, 7
-15, 7-16, 7-17, 7-18 are known variable delay lines, which are circuits whose delay time changes with control voltage;
7-19 is an inverting multiplier similar to inverting multiplier 7-6, and 7-20 is an inverting multiplier whose input is output only when a gate signal is present, such as one using a diode bridge. This is the circuit.

7-21 is an inverter, 7-22 is a NAND circuit, 7-23 is a set-reset flip-flop, 7-24 is an inverter, 7-25 is a NAND circuit, 7-26 is a delay line with a fixed delay time, 7-22 is a set-reset type flip-flop, 7-24 is an inverter, 7-25 is a NAND circuit, 7-26 is a delay line with a fixed delay time, 27 is a set-reset type flip-flop, 7-28 is a NOR circuit, 7
-29, 7-30, 7-31, 7-32 are each NAND
It is a circuit.

7-33, 7-34, 7-35, 7-36 are inverters, 7-37 and 7-38 are NOR circuits, 7-39 is a set-reset type flip-flop, and 7-40 is a NOR circuit.
7-41 is a variable multiplication rate multiplier, which is a known circuit that controls the multiplication rate by utilizing the fact that gm changes depending on the emitter current of a transistor, and 7-42 is a fixed delay multiplier. The timed delay line 7-43 is a pulse generator similar to the 7-5 sampling pulse generator.

7-44 is a delay line with a fixed delay time, 7
-45 is a sampling circuit similar to 7-4, 7-46 is a shaping circuit such as a Schmitt trigger circuit, 7-47
is an inverter, 7-48 are NOR circuits, 7-49 are NA
ND circuit, 7-5 river inverter, 7-51 is a sampling circuit similar to sampling circuit 7-4, 7-52 is a NOR circuit, 7-53 is a NAND circuit, 7-54
is a delay line with a fixed delay time, 7-55 is a sampling/V-less generator similar to the sampling pulse 7-5 generator, and 7-56 is an output terminal for deriving the corrected recording signal voltage. It is.

Next, the operation of each part will be explained with reference to the waveform diagram in FIG.

An example of the recording signal voltage (hereinafter abbreviated as signal) applied to the input terminal 7-1 to be corrected is shown in FIG. ．． o,
,t,.

2... etc. for time o, ~t,.

2=Lo2~t skin=t, o9~t,. Omata t,.

3~t,.

4=tIQ~tlo9, Lo4~et al.

5 = et al.

5~Lo5=Lo6~et al.

7 = et al.

7~ra.

8 and it is o, ~ t side ni 2 (tl.

3~tl.

4), h.

3-t similar to 4/3 (tl.

4-ch.

5).

One of the signals is that the NOR circuit 7-2 and the sampling pulse generator 7-5 generate a sampling pulse 1 (shown in Fig. 8-2) of 7,0 in the pulse at the falling edge of the signal. -2, therefore, the output of the NOR circuit 7-2 is applied at the falling point 7.2 as shown in Figure 8-3. . The resulting waveform is input to the triangular wave generator 7-3 and the sampling circuit 7-4. Figure 8-4 shows the integrated voltage waveform (integrated voltage 1) generated by the triangular wave generation circuit 7-3, and the sampling operation is reliable in the flat part of the time corresponding to d and o at the peak of the triangular waveform. For example, in an integral operation such as charging a capacitor with a constant current and obtaining a triangular waveform depending on the terminal voltage, 7.
0 can be achieved by a circuit that causes a discharge current equal to the charging current to flow out from the capacitor. The integrated voltage 1 is obtained by a sampling circuit 7 using known means.
14, the sampling pulse 8-2 from the sampling pulse generator 7-5 is sampled, and the voltage at the peak flat portion of the integrated voltage 1 is held by a hold capacitor (not shown). On the other hand, the sampling pulse 2 having a width of approximately equal to lo, which is generated at the rising edge of the signal applied to the sampling pulse generator 7-1 through the inverting multiplier 7-6, is generated by the 8-5th pulse generator 7-6. The output waveform is generated as shown in the figure, and an output waveform as shown in FIG. 816 can be obtained by the triangular wave generator 7-8 in the same manner as described above. Since a hold capacitor (not shown) is commonly provided to the outputs of the sampling circuits 7-4 and 7-9, the terminal voltages of the hold capacitors are E-skin, . o2... will change to willow. Here E,
= E side = E, Q, and E,. 5=E,.

8.E.

4=E, 5=E,.

6=E,.

? It is. As mentioned above, correction is required depending on the moving speed of the recording medium and the time between the signal change points, that is, during the pulse and the diameter of the optical spot used for recording. Since it is determined that the pulse is in the middle, the sampling voltage shown in FIG. E, corresponding to the time of 4.

3 is that.

The discriminator 7-11 has a sampling voltage. It has a function of outputting only when the value is less than 3, and its output is shown in Fig. 8-8.

(The output shown in Fig. 8-8 is referred to as a correction voltage.) The correction voltage is input to each intensifier 7-12, 7-13, 7-14,
7-12 and 7-14 are linear multipliers that maintain a linear relationship between normal input and output, and the respective outputs are corrected to voltages 1 and 3. Multipliers 7-13 output ON-OFF signals. . For example, with something like a Schmitt circuit, this output can be converted to a correction voltage of 2
(Illustrated in Figures 8-9). 7-15, 7-16, 7-
17 and 7-18 are variable delay lines, respectively, and 7-15 and 7-17 are variable delay lines depending on the combination with the outputs of the gate circuits 7 and 20, and 7-15 and 7-17 are delayed as the control voltage increases. Time decreases, also 7-16, 7-1
7, the control voltage is in reverse phase due to the inverting multiplier 7-19,
Therefore, on the contrary, the delay time increases.

The correction voltage 2 of the multiplier 7-13 is the flip-flop 7-2.
3 and inverters 7-24 to flip-flops 7-27, and flip-flops 7-23
It is set at the falling edge of the illustrated signal, and the flip-flop 7-27 is set at the rising edge by the inverter 7-24. On the other hand, the output of the NOR circuit 7-40 generated at the rising and falling points of the corrected signal obtained as described later is inputted to 7-22 and 7-25, and therefore the flip-flop 7-23 is connected to the correction voltage 2. The point in time when L occurs. After being set at 5, the flip-flop 7-27 is reset by the output from the NOR circuit 7-40 (10a shown in FIG. Output (Fig. 8-13 1)
0b), the Q output of flip-flops 7-23 is as shown in FIGS. 8-10, and the Q output of flip-flops 7-27 is as shown in FIGS. 8-11.

Since the delay line 7-26 has a delay time 11 approximately equal to times 10 and 10', the input to the NOR circuit 7-28 is from time 8-11 as shown in FIG. Time L2 delayed by 11 from 8, 11 from 24 from time 24 to be described later
A signal having a pulse duration of up to 22 times late is applied.

The Q output of each flip-flop 7-23, 7-24 is NO.
It is mixed by the R circuit 7-28 and inputted to the gate circuit 7-20', and outputs the correction voltage 3 from the multiplier 7-14 only during the time when the pulse exists. This output is inputted to each variable delay line 7-15, 7-17 and to each variable delay line 7-16, 7-18 via an inverting multiplier 7-19. The variable delay lines 7-15 and 7-17 are the 8th-1st
The delay time is controlled only for the first pulse input to the variable delay lines 7-15 and 7-17 from the time when the pulses shown in Figures 0 and 8-11 are generated, that is, from the time when the correction voltage is generated. The output is delayed by a fixed delay time, while the variable delay lines 7-16 and 7-17 are output in the opposite direction. Figure 8-12 shows the output of variable delay line 7-15, Figure 8-13 shows the output of variable delay line 7.
-18 outputs, respectively, from the point in time when the correction voltage 3 is not generated. 2.

2' or the time between T blood and T plate' correspond to constant delay times 7 and 2, respectively, and the pulse 10a (hereinafter referred to as a correction pulse) is delayed due to the correction voltage 3.

4', and the time t side' has advanced to time t,24.

The reason why two sets of variable delay lines are provided here is that it is necessary to consider whether to advance or delay the correction pulse at both the rising and falling points of the signal, and also because the fixed delay time is the signal pulse width time that requires correction, ie at time o3. The choice is approximately equal to or less than 4.

The pulse generator 7-43 generates a pulse at both the rising and falling points of the output pulse of the NOR circuit 7-28, and the delay time is variable between the delay lines 7-15...
The signal passing through the delay line 7-44, which has a delay time approximately equal to 2, is sampled by the sampling circuit 7-45, and the signal is sampled by the sampling circuit 7-45. The sample voltages at 5, 2 and 2 and the correction pulses at 23 and 24 determine whether the change in the signal occurs at the rising or falling point.

This output is formed by a forming circuit 7-46, for example, a Schmitt circuit, and then passes through NAND circuits 7-30, 7-32 and inverters 7-47 to each NAND circuit 7-29, 7-3.
1 is input. Each NAND circuit 7-29...
7-32 and each variable delay line 7-15...
- From the combination 7-18, if the correction signal corresponds to the rising edge of the signal, each NAND circuit 7-30, 7-32
operates and corresponds to the falling point, each NAND circuit 7-29, 7-31 operates, and in this example, the outputs of NAND circuits 7-30 and NAND circuits 7-32 are respectively Shown in Figures 8-12 and 8-13. Each NAND
The outputs of circuits 7-29 and 7-30 are connected to inverters 7-3, respectively.
9 and 7-34, are mixed by a NOR circuit 7-37, and input to the set terminal of a flip-flop 7-39.

On the other hand, the outputs of the NAND circuits 7-31 and 7-32 are applied to the NOR circuit 7-38 via inverters 7-35 and 7-36, and this output is also applied to the flip-flop 7-39 of the same machine.
input to the reset terminal. Figure 8-14 shows the flip
The waveform of the Q output of flop 7-39 is illustrated. NOR circuits 7-48 make use of pulses at each rising and falling point of the signal, and the pulses are passed through NAND circuits 7-49 and NOR circuits 7-52 to sampling IJ pulse generators 7-55.
As a result, the sampling operation to be described later is performed satisfactorily, and a sampling pulse having a width sufficiently narrow compared to the correction pulse width is inputted to the sampling pulse input terminal of the sampling circuit 7-51. The output of the inverter 7-50 connected to the output of the NOR circuit 7-28 causes the
The output of the NOR circuit 7-49 is blocked at the time when the correction pulse is generated, and at this time, the output of the NOR circuit 7-40
The output of the sampling circuit 7-51 is inputted via the NAND circuit 7-53 and the NOR circuit 7-52, and thus the waveform shown in FIG. 8-15 is outputted to the output of the sampling circuit 7-51.
Note that the delay line 7-54 has a delay time approximately equal to the sampling pulse width, so that the sampling pulse generated at the time t side holds the voltage corresponding to the E side, and at time t, 24. The output of the 7-51 sampling circuit is shown in No. 8-15 as it is newly sampled and held depending on the next sampling pulse to be generated. The output of the 7-51 sampling circuit is input to the 7-41 variable amplifier and is input to the 8th-41 variable amplifier.
15, the gain changes depending on the signal shown in the figure, i.e., if the signal is low, the gain changes so that the gain increases, and during the time when no correction is required, the amplification is constant, so that the 7-56 output terminals have the 8-16 The corrected recording signal voltage shown in the figure is obtained.

Note that the 7-40 delay line is for correcting a time delay corresponding to the pulse width of the sampling pulse. In the above explanation, we took silver halide film as an example of a recording medium, and assumed that its characteristics are that the density has a linear relationship with the exposure amount, but generally speaking, this assumption holds true only when the recording medium is This is a case where the recorded density change amount is limited to a very small part of the recordable density range.

Next, if the above linear relationship is not satisfied and in the extreme case the exposure amount is less than a certain threshold, the density Dmin12
, correction in the case where there is a binary change with Dmax12 above the threshold value will be explained.

(Hereinafter, the corrections shown in figures 7 and 8 will be referred to as the first corrections 11 and 12.
The illustrated correction is referred to as a second correction. ) Figure 9-1 shows the first
An example of the corrected recording signal voltage is shown, and FIG. 912 shows the amount of exposure given to the recording medium. Note that FIG. 9-1 corresponds to FIG. 6-4, FIG. 9-2 corresponds to FIG. 6-3, and the relationships of the machine axes, etc. in FIG. 9 are the same as in FIG. 6.
Now, the recording medium, in this example, a silver halide film, has a dark value at P, 2, shown in Figure 9-2 of the exposure amount, and for an exposure amount greater than P, the density changes to Dmax121, P, 2. , hereinafter, Dmin121, the recording pattern obtained in this case is as shown in FIG. 9-3. 9th
As is clear from FIG. 3, it is clear that errors of 1, 2, 1, 2, etc. occur, unlike the recording pattern of FIG. 6-1. Fig. 10 shows the case where the second correction in such a case is added to the recording signal voltage after the first correction, and Fig. 10-1 shows the desired recording pattern (same as Fig. 6-1). Fig. 10-2 shows the amount of exposure to the recording medium due to the first corrected recording signal voltage (same figure as Fig. 9-2), and Fig. 10-3 shows the amount of exposure. A recording pattern (FIG. 9-3 and the same figure) on a recording medium when the threshold value is P skin is shown.

The error lengths in Figure 10-3 are 1, 2,, 1, 22
It is shown in The second correction in this case can be considered as follows.

In other words, the time point at which the recording signal voltage is changed is determined by the error length 1 on the recording pattern being 1 in relation to the moving speed v of the recording medium.
Is it possible to correct this by advancing or delaying the time by /v?
3,=Completion ".7,32=Akira respectively, delayed, advanced...
. . . It is sufficient to perform the delay and the second correction.

For reference, the recording signal voltage without the second correction is shown in FIG. 10-4. Also, the time is right. 3, 7, and 32 are determined if the slope and the threshold value of the exposure amount at the time of the change in the exposure amount are given. Fig. 10-16 shows the temporal change in exposure amount due to the second corrected recording signal voltage (shown in Fig. 10-14), and Fig. 10-7 shows the case where there is a threshold P skin of the exposure amount. It is clear that the second correction is effective.

In this case, since there is a relation value to the exposure amount, 10-6
The disturbance in FIG. 136 is not a problem. Next, the second correction method is specifically shown in FIG.

In FIG. 11, functional blocks that overlap those in FIG. 7 are designated by the same numbers as in FIG. Here, 1 1-1 is a variable delay line, and 1 1-2 is a stretch line, which has the function of maintaining the voltage at the end of the correction voltage of the input signal (shown in Figure 8-8) for a certain period of time, for example. ,A/
This method uses a D converter to store voltage data at the above point in a shift register or the like, outputs this data to a D/A converter, holds it, and resets it after a certain period of time. Reference numeral 11-3 is an output terminal for the recording signal voltage subjected to the first and second corrections. The output of the seventh illustrated flip-flop 7-39Q is illustrated in FIG. 12-1 for convenience in the following explanation. The output of NOR circuit 7-37 is variable delay line 1
1-1, and is delayed by a set delay time 7, 4, 4, 42 in relation to the moving speed of the threshold value recording of the exposure amount and the diameter of the light spot. Here, 7, 4, (7, 4, = 27 skin) is the delay time during the time when the correction voltage is not generated, and the exposure amount during the time when the correction voltage is generated as shown in Figure 10-12. Since the forehead inclination changes, the delay time is changed in relation to the correction voltage and becomes T, 42. However, if A, 42 is 7, 42 = D, the interval between each pulse will change. The value is corrected by the amount. Variable delay line 1 1
The output of -1 is input to the set input of flip-flop 7-39, while the output of NOR circuit 7-38 (shown in figure 12-3) is input to the reset terminal of flip-flop 7-39.
A signal as shown in FIG. 12-4 is obtained at the Q output of -39.

On the other hand, the output of the sampling circuit 7-51 passes through the stretcher 11-2 and becomes the waveform shown in Figure 12-5. Here, the output of the stretcher 11-2 is corrected by the output of the sampling circuit 7-51. The signal ends at time t24, but due to the action of stretcher 1 1-2, time t
,5,. Variable increase rate intensifier 7-
The output of 41 is the output of stretcher 11-2 (12th-
5), the oscillation is controlled in the same way as explained in FIG. 3
is output to. In the above detailed description of the present invention, it is assumed that the light intensity distribution of the light spot is uniform, but the gist of the present invention can also be applied to cases where the light intensity distribution is Gaussian distribution, for example. Needless to say, the present invention can be similarly applied to a rectangular spot instead of a circular spot.

Furthermore, although the recording signal voltage has been described using a rectangular waveform as an example, it can also be applied to recording a sine waveform. Furthermore, although a silver salt film was used as an example of the recording medium, it is clear that this can also be applied to other recording bodies such as photosensitive resins (photoresists). Furthermore, the gist of the present invention is, for example, when reproducing a recorded pattern recorded at a constant density, due to the different recording lengths of the recorded pattern after photoelectric conversion, which occurs due to photoelectric exchange with a reproduction light spot having a finite size. On the other hand, it can also be applied to a means of correcting points where the output oscillation differs and obtain an output with approximately constant oscillation, and is also suitable when the amount of change in density, for example, of a recording pattern is predetermined. This makes it possible to apply a driving signal voltage of 200 to an optical modulator, and the effects of the present invention are tremendous.

[Brief explanation of the drawing]

Figure 1 shows the principle of optical recording. Figure 2 is an explanatory diagram of the amount of exposure on a recording medium due to a light spot with a finite size, Figure 2-1 is an enlarged perspective view of the main part in Figure 1, and Figure 2-2 is An explanatory diagram showing the exposure amount at each point on the recording medium, and FIGS. 2-3 are explanatory diagrams of the drive signal voltage applied to the modulator. FIG. 3 is a diagram for explaining recording on a recording medium, FIG. 3-1 is an explanatory diagram showing the drive signal voltage applied to the modulator, FIG. 3-2 is an explanatory diagram showing the beam radiation intensity, 3-3 is an explanatory diagram showing the exposure amount at each point on the recording medium, and FIG. 3-4 is an explanatory diagram showing the recording density of the recording medium. Figure 4 shows how the recording pattern changes depending on the recording wavelength, Figure 4-1 is an explanatory diagram showing the drive signal applied to the modulator, and Figure 4-2 is an explanatory diagram showing the amount of exposure to the recording medium. , FIG. 4-3 is an explanatory diagram showing the recording density of the recording medium. FIG. 5 provides an explanation of the first correction method according to the present invention, FIG. 5-1 is an explanatory diagram showing the ideal recording density on the recording medium, and FIG. FIG. 5-3 is an explanatory diagram showing a drive signal voltage waveform for obtaining the recording pattern shown in FIG. 5-2. FIG. 6 shows the first embodiment according to the present invention.
6-1 is a pattern density waveform diagram on a recording medium, FIG. 6-12, FIG. 6-6, 6-3 and 6-5 are the density waveforms on the recording medium, and 6-4 is the density waveform shown in FIG. 6-3. The drive signal voltage waveform diagram for obtaining
Enlarged view of the main part of the figure. FIG. 7 is a block diagram showing a signal recording method according to the present invention. 811-16 are waveform diagrams at each point shown in FIG. 7 for explaining the operation of FIG. 7. 9th
The figure is an explanatory diagram when there is no linear relationship between the exposure amount of the recording medium and the recording density. Figure 9-1 is a drive signal voltage waveform diagram;
FIG. 12 is an explanatory diagram showing the exposure amount, and FIG. 9-3 is a waveform diagram showing the recording density on the recording medium. FIG. 10 is an explanatory diagram illustrating a preferable recording signal in the case of FIG. 2,
Figure 10-1 is a density waveform diagram on the recording medium, Figure 10-2
The figure is an exposure amount waveform diagram, Figure 10-3 is a density waveform diagram on the recording medium, Figure 10-4 is a drive signal voltage waveform diagram after the first correction, and Figure 10-5 is a diagram of the drive signal voltage waveform after the first correction. The second corrected drive signal voltage waveform diagram, Figure 10-6 is the exposure amount waveform diagram, Figure 10-6 is the drive signal voltage waveform diagram after the second correction.
FIG. 7 is a concentration waveform diagram. FIG. 11 is a block diagram showing a signal recording method for applying the second correction;
-1 to 6 are signal waveform diagrams at each part shown in FIG. 11. Here, 7-15, 7-16, 7-17, 7-1
8, 11-1 are variable delay lines, 7-44, 7-4
2, 7-54 are delay lines, 7-3, 7-8 are triangular wave generators, 7-4, 7-9, 7-45, 7-51 are sampling circuits, 7-5, 7-10, 7 155 is a sampling pulse generator, 7-23, 7-27, 7-39 are flip-flops, and 7-41 is a variable multiplication rate intensifier. Younger brother Ryōzu Yuzo-no drawing Younger brother 2-2 drawing 2-yo drawing 3-cho drawing 3-2 maiwo-3 design...-4 drawing 4-no drawing 4-2 drawing 43 drawing Takashi Evening S-Z Figure Turnip S-Sho Figure 6-R Figure 6-2 / 6-S Figure 6-4 Figure 6-S Figure 6-6 Hanman7 Figure 5 -8 Figure 7 Figure 8-' Figure 8-2 Figure 8-3 Figure 84 Figure 8-S Figure 8-5 Figure 8 Figure 8-)S Figure 876 Figure 8- Figure 7 Figure 8-8. Sixth? Figure 8-'oFigure 8-Figure 8-'2Figure 8-B Figure Hair?Figure Hisashi Aoi2 Figure Younger BrotherS3 Figure Younger Brother Shio's Plan-2 Figure NozuzuAtsushio A collection of J illustrations of plans - Collecting 6 illustrations - No. 2 plans for the plan... 3rd plan for the plan... 3rd plan for the plan

Claims (1)

[Claims] 1. In a recording method in which recording is performed by scanning a recording medium with a light spot modulated by a recording signal, when the value of the recording length becomes smaller than a predetermined value due to the diameter of the light spot in the running direction of the light spot, the above-mentioned A signal recording method characterized in that the recording signal is corrected so that the amount of light irradiated by the recording signal is increased.