JPH03152724A - Access method for optical card - Google Patents

Abstract

PURPOSE:To attain accurate and high speed access by providing an absolute position detector to an optical pickup, expressing the relative position relation between the absolute position detector and an optical card in a linear equation by self-study, and driving a linear motor along with the linear equation. CONSTITUTION:An optical pickup 1 is connected to a linear motor 2, a sensor contact 4 is moved while being in contact onto an absolute position sensor 3 when the optical system is driven by a linear motor 2. When an optical card is loaded to a reader and writer, the relative position relation between the absolute position detector 3 and the optical card is studied to calculate a linear equation representing the relation between the track position of the optical card and the output of the absolute position detector 3. In the case of succeeding access, an object track number is substituted in the linear equation to calculate the output of the absolute position detector at an object track position reversely, then the object position is decided to be driven by the linear motor and the optical pickup is drive up to a object position at high speed. Then high speed and accurate access is realized.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an access method for an optical card having a large capacity information storage function.

BACKGROUND OF THE INVENTION In recent years, reflecting the age of cards, optical cards have been actively developed as cards following magnetic cards and XC cards.

Optical guard is 2oo to increase information recording density.

The book is made up of 3000 track lines, and it is required to access the target track in a short time.

Conventional access methods can be roughly divided into two types: one is to drive the optical pickup without feedback using a motor capable of absolute position control, such as a pulse motor, and the other is to access the optical pickup. In this method, the pickup is driven by a high-speed motor such as a linear motor, the drop in light intensity is detected when the laser beam crosses the track line, and the amount of movement is detected by counting the number of times the light intensity decrease occurs to access the pickup.

Problems to be Solved by the Invention However, in the former example of the above conventional methods, there is a limit to the driving speed of the optical pickup (smoke), and that limit speed is 17% compared to the limit speed of a near motor, etc. In the latter example, the number of times the light intensity decreases when the laser beam crosses the track line is counted, so there is a fingerprint 1i 1 on the optical card. If there is a foreign object such as a lump, there is a problem in that the measurement is erroneous and accurate movement distance cannot be obtained.

Means for Solving the Problems In order to solve the above problems, the present invention provides an absolute position detector in the optical pickup and expresses the relative positional relationship between the absolute position detector and the optical card by a linear equation through self-learning. However, by driving a linear motor using this linear equation, accurate and high-speed access is possible.

Effect of the Invention With the above-described configuration, the present invention learns the relative positional relationship between the absolute position detector and the optical card when the optical card is loaded into the read/write device, and learns the relationship between the track position of the optical card and the output of the absolute position detector. Calculate the linear equation representing . For subsequent access, by substituting the target track number into the above linear equation, the output of the absolute position detector at the target track position can be calculated backwards, so the target position to be driven by the sunar motor can be determined, allowing high speed It is possible to drive the optical pickup to the target position. As a result, fast and accurate access can be achieved.

Embodiment FIG. 3 shows an external view of an optical card. is the data recording section,
B is a portion in which track numbers are recorded in advance. Further, C is the data read/write direction.

FIG. 2 shows a sketch of an access mechanism according to an embodiment of the present invention. The optical pickup 1 is connected to the linear motor 2, and the sensor contact 4 is also connected at the same time. Therefore, when the optical system is driven by the linear motor 2, the sensor contact 4 moves while contacting the absolute position sensor 3. Since the absolute position sensor 3 uses a type of linear variable resistor, it is possible to obtain a position information voltage proportional to the amount of movement of the optical system.

FIG. 1 shows a block diagram of an access control circuit according to an embodiment of the present invention. 60 microcomputer side, D/
When target position data is sent to the D/mu converter, the D/mu converter outputs a target position potential 12. Differential amplifier 8
is the position potential 11 of the absolute position sensor 3 and the target position potential 1
Output the difference between 2. The servo circuit 9 performs phase compensation of the differential output, and the power amplifier 10 drives the linear motor 2 at high speed. As described above, this embodiment has a negative feedback control circuit, and even if the linear motor 2 is driven at high speed, it can be stopped at the target position with high accuracy. Note 1
3 is a read signal, 14 is a preamplifier, and 16 is a 1 track number demodulator.

The actual access procedure will be explained below.

The inspection of the relative positional relationship between the optical card 6 and the absolute position sensor 3 that is executed when the optical card 6 is loaded into the read/write device is called learning, and this learning will be explained using FIG. 4. First, the microcomputer 6 outputs the target potential v1 from the D/mu converter. Then, the near motor 2 drives the optical pickup 1 to a position where the position potential becomes vl. After the movement is completed, the optical card 6 is driven and the track number N1 at that position is read. Next, the target potential v2 is output from the D/mucompert.

Then, the linear motor 2 drives the optical pickup 1 to the position where the position potential becomes vl, and the track number N2 is read in the same way.

Thereafter, the microcomputer 6 determines a linear equation of vDm=t×NTR+b. Here, vDmu is the target potential to be output from the D/mu converter, and NTR is the track number.

a is the slope, b is the vDM intercept, IL=(V2 L )/(12Ml ), 1)==v
1-aN1 Also, it can be found as =V2-aN2.

Once the linear equation is determined, subsequent accesses can be performed based on this linear equation. The method will be explained below. If the track number to be accessed is NR, then the target potential vR to be output from the D/mu converter becomes VR==lLXNR+b by substituting NR into the linear equation.

Since a and b are known, vR can be found. If you output that value from the D/mu converter, the optical pickup 1
is driven to the location of track number NR, so access has been achieved. Since learning is performed each time the optical card 6 is loaded into the read/write device, it is possible to absorb manufacturing errors of the optical card 6, physical positional deviation during loading, and deterioration in accuracy of the mechanical system due to changes over time.

Effects of the Invention As described above, the present invention enables the optical pickup to be driven to the target position at high speed, and also absorbs physical positional deviations of the optical card, so it is possible to drive the optical pickup to the target position at high speed. Access can be achieved.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an access control circuit according to an embodiment of the present invention, FIGS. 2(a) and 2(b) are top and perspective views of essential parts, FIG. 3 is a top view of an optical card, and FIG. The figure is an explanatory diagram of a learning operation in an embodiment of the present invention. 1... Optical pickup, 2... Linear %-tameter, 3... Absolute position sensor, 6...
・Light card.

Claims (1)

[Claims] An optical pickup of the optical card read/write device is provided with an absolute position detector, and a linear motor connected to the optical pickup is driven while applying negative feedback with the output of the absolute position detector, and the optical card and the absolute position detector are connected to each other. A method for accessing an optical card, characterized in that the relative positional relationship between the two is expressed by a linear equation through self-learning, and the linear motor is driven based on this linear equation.