JPH0132167Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for measuring the mounting position of a magnetic head used, for example, in a VTR (video tape recorder).

As is well known, the magnetic head used in a VTR has various characteristics such as the mounting position relative to the head support, such as the upper cylinder, the degree of protrusion relative to the outer peripheral surface of the upper cylinder, and the height relative to the end surface of the upper cylinder.
Very strictly regulated. Conventionally, measuring the mounting position of the magnetic head and determining whether the error in the mounting position is within an allowable range has been extremely complicated, requiring skilled techniques or a long measuring time, which has resulted in a long time. The problem was that it was inefficient.

The present invention was developed based on the above-mentioned circumstances, and its purpose is to be able to extremely easily and precisely measure the error in the actual mounting position of the magnetic head relative to the reference mounting position. The object of the present invention is to provide a measuring device that can instantly read the information.

An example in which the present invention is applied to a device for measuring the protrusion of a magnetic head for a VTR is shown in Figs. 1 and 2.
This will be explained based on the diagram.

First, an overview of the measuring device that is this example will be explained in the first section.
This will be explained in the figure. This measuring device images the mounting state of the magnetic head of a rotary head (the figure is a cross-sectional view) indicated by reference numeral 1 using an imaging device indicated by reference numeral 2,
This imaging result is displayed on a screen 4 of a screen display device (for example, a CRT display) indicated by reference numeral 3, and a first vertical line 5 and a second vertical line 6, which are movable left and right, are displayed on this screen 4, respectively. I am trying to display it. Then, align the first vertical line 5 with the position corresponding to the correct mounting position (reference position) of the magnetic head on the screen 4, and align the second vertical line 6 with the position of the actual magnetic head shown on the screen 4. When the magnetic head is moved to match the mounting position, the mounting error of the magnetic head is automatically calculated from the difference between the two vertical lines 5 and 6, and is numerically displayed as a distance on the display device 7.

Each part of this embodiment will be explained in detail below.
The rotary head 1 has an upper cylinder 8 as a head support, as shown in the bottom view in FIG.
The upper cylinder 8 has two magnetic heads 9 attached to the lower surface thereof. in this case,
The magnetic heads 9, 9 have their head surfaces 9a, 9
a faces the outer circumferential surface 8a of the upper cylinder 8, and are attached so as to be in a mutually symmetrical positional relationship with respect to the axis of the upper cylinder 8. Further, in this case, the magnetic heads 9, 9 have their respective head surfaces 9
A, 9b are attached so that the degree of protrusion from the outer circumferential surface 8a can be adjusted. The rotary head 1 is fixed to a jig (not shown) in the positional relationship shown in FIG. The imaging device 2 is
The lens 1 fixed to the jig is used to image the vicinity of the head surface 9a of the one magnetic head 9.
0, 11, a half mirror 12, and a light source 13, an image pickup tube 14, and an image pickup tube control circuit 15 that performs scanning control of the image pickup tube 14. In this imaging device 2, light emitted from a light source 13 is reflected by a half mirror 12 and reaches the vicinity of the head surface 9a of the magnetic head 9. After being reflected here, the light passes through the lens 10, the half mirror 12, and the lens 11 in sequence and enters the image pickup tube 14, where it is formed as an enlarged image. In addition, the image pickup tube control circuit 15
When the input end 15a is supplied with a horizontal synchronization signal and a vertical synchronization signal, the output end 15b sends a scanning signal to the image pickup tube 14, and at the same time, the output of the image pickup tube 14 is inputted to the input end 15c. An imaging signal is generated by superimposing both the synchronization signals on the output terminal 15.
It is configured to be transmitted from d.

Next, 16 is a clock generation circuit that generates a clock signal CLK. Further, 17 is a synchronization signal generation circuit, and this synchronization signal generation circuit 17 divides the frequency of the clock signal and CLK to generate a horizontal synchronization signal Sh.
is generated and frequency-divided to generate the vertical line synchronization signal Sv.
The synchronizing signals Sh and Sv are supplied to the image pickup tube control circuit 15, while the vertical line generating circuit 18, the horizontal line generating circuit 21, and the counting circuit, which will be described later, generate both the synchronizing signals Sh and Sv and the clock signal CLK. 25 respectively. Note that the horizontal synchronization signal Sh is an integral multiple of the clock signal CLK, for example 1000.
It has twice the period. The vertical line generation circuit 18 generates signals S _l1 and S l2 for displaying the first vertical line 5 and the second vertical line 6 on the screen 4, respectively, and at the same _timing as these signals S _l1 and S _l2 . Signal S _l1 ′,
This is a circuit that generates S _l2 ′ respectively, and also 19, 2
0 are first and second adjusters provided to adjust the display position of the first vertical line 5 and the display position of the second vertical line 6, respectively. In this case, the vertical line generating circuit 18 has a counter that is cleared by the horizontal synchronizing signal Sh and counts the clock signal CLK, and the count value of this counter is the output value of the first regulator 19. signal when it matches
S _l1 , S _l1 ′ are generated, and when the count value of the counter matches the output value of the second regulator 20, signals S _l2 ,
It is configured to generate S _l2 ′. The horizontal line generation circuit 21 is a circuit that generates a signal _Sl3 for displaying a horizontal line 22 on the screen 4. This horizontal line generation circuit 21 has a counter that is cleared by the vertical synchronizing signal Sv and counts the horizontal synchronizing signal Sh, and the counted value of this counter is a predetermined value (for example, from the top to the bottom of the screen 4). When the horizontal line 22 is displayed at the half-stroke position, a signal S _l3 is generated. 23
is a video synthesis circuit, and this video synthesis circuit 23
is the output end 15d of the above-mentioned image pickup tube control circuit 15.
The video signal output from the vertical line generating circuit 18
The signals S _l1 and S _l2 generated by the horizontal line generating circuit 21 are combined with the signal S _l3 outputted by the horizontal line generation circuit 21, and the image is projected on the screen 4 by the composite signal output from the image combining circuit 23. It's summery. Reference numeral 24 is a distance calculation circuit, and in this distance calculation circuit 24, a counting circuit 25 is connected to the vertical lines 5 and 6.
This is a counter that calculates the distance corresponding to the distance between the two clock signals as a count value of the clock signal CLK. This counting circuit 25
is cleared by the preceding signal of the signals S _l1 ′ and S _l2 ′ within each period of the horizontal synchronization signal Sh and is placed in a countable state, and then is counted by the subsequent signal. The clock signal CLK is counted until the clock signal CLK is inhibited. In this case, the counting circuit 25 receives a signal for generating the first vertical line 5.
If S _l1 ' precedes, the clock signal CLK is added and counted to generate the second vertical line 6.
If S _l2 ' precedes, the clock signal CLK is subtracted and counted. Next, the magnification setter 26 receives the clock signal
This is a setting device for setting the distance actually corresponding to one cycle of CLK, and this magnification setting device 26 outputs a value in units of (μm/count), for example. The arithmetic circuit 27 calculates the distance corresponding to the vertical lines 5 and 6 by multiplying the count value output by the counting circuit 25 and the value output by the magnification setter 26, and displays this calculated distance on the display device 7. Send to. The display device 7 displays the above-mentioned distance numerically.

Next, the operation and operation of this embodiment having the above configuration will be explained. First, prior to measurement, the operator fixes a gauge at the location where the rotary head 1 is to be fixed, and displays this gauge on the screen 4. Next, the operator operates the adjuster 19 to align the vertical line 5 with the first scale corresponding to the reference position of the head surface 9a engraved on this gauge, and also operates the adjuster 20 to align the vertical line 5 with the first scale corresponding to the reference position of the head surface 9a. 6 to coincide with a second scale engraved on the same gauge (the distance between the scale and this scale is known). Here, the operator adjusts the magnification setter 26 so that the distance displayed on the display device 7 matches the distance between the two scales. When the above adjustments are completed, the gauge is removed and the rotary head 1 to be measured is fixed instead.
In this case, the image of the head 9 in the same rotating head 1 will look like the shaded area on the screen 4 in FIG. 1, for example. Here, the operator operates the adjuster 20 to align the second vertical line 6 with the position of the head surface 9a indicated by the image of the head 9. Note that the first vertical line 5 is designed in advance to indicate the correct protruding position of the head 9, that is, the reference position. In this way, the display device 7 numerically displays the distance between the standard protruding position and the actual protruding position of the magnetic head, that is, the installation error regarding the degree of protrusion.
If the degree of protrusion is greater than a standard value (for example, zero), that is, if the vertical line 6 is on the right side of the vertical line 5 on the screen 4, the counting circuit 25 adds and counts as described above. Errors are displayed as positive values. On the other hand, if the degree of protrusion is smaller than the standard value, that is, if the vertical line 6 is on the left side of the vertical line 5, the counting circuit 25 performs subtraction and the mounting error is displayed as a negative value.

As mentioned above, when measuring the deviation of the mounting position of the magnetic head 9 from the reference position using this measuring device, first align the first vertical line 5 with the correct position of the magnetic head 9 in advance. Thereafter, the head surface 9a of the magnetic head 9 to be measured is aligned with the second vertical line 6.
Measurements can be made by simply matching the Furthermore, since the measurement results can be directly read as numerical values, it is possible to immediately determine whether the deviation in the mounting position is within the allowable error range. moreover,
Since the first and second vertical lines 5 and 6 are moved, even if a positional shift occurs in the image pickup tube 14 of the video signal 2, measurement can always be performed accurately.

That is, in a case where the rotary heads 1 to be measured are limited to those of the same type, it is conceivable to keep the first vertical line 5 fixed. However,
If the first vertical line 5 is fixed, the image pickup device 2 may change over time, or a shock may be applied to the image pickup tube 14 due to a handling error, which may cause the orientation and position of the image pickup tube 14 to be distorted. If this occurs, for example, if the position of the image pickup tube 14 shifts in the left-right direction in FIG. 1, an error will occur in the measurement results by the amount of the shift. Of course, the imaging tube 14 of the imaging device 2
If there is a deviation in the mounting position, the mounting position of the imaging device 2 may be readjusted so that the first vertical line 5 is located at the normal position. In order to do so, the fixing system of the imaging device 2 must be loosened, the first vertical line 5 must be adjusted to the proper position, and the fixing system must be tightened again, which requires a great deal of effort. Moreover, if the screw is retightened after adjustment, an error may occur due to the retightening, and adjustment of the imaging device 2 requires a high degree of skill.

In this regard, according to the measuring device of the present invention, not only the second vertical line 6 but also the second vertical line 5 is movable, so that there is no problem in the mounting position of the imaging device 2, especially the imaging tube 14. Even if this occurs, if the second vertical line 5 is aligned with the normal position, such deviation will not have any effect on the measurement results. Therefore, measurements can always be made accurately. Also,
It is only necessary to align the first vertical line 5 with the regular position, and the effort required for adjusting the measuring device 2 can be saved.

In addition, in the above embodiment, the head surface 9a
Although the degree of protrusion of the magnetic head 9 is measured, the present invention can also be applied to the case of measuring the height of the magnetic head 9 with respect to the end surface 8b of the upper cylinder.

Further, in the above embodiment, the horizontal synchronization signal Sh and the vertical synchronization signal Sv are generated based on the clock signal CLK from the clock generation circuit 16, and
Error measurement is performed by counting this clock signal CLK by a counting circuit 25. In this way, everything is controlled based on the clock signal CLK from the only clock generation circuit 16, so if there is a fluctuation in the period of the clock signal CLK counted by the counting circuit 25, the horizontal synchronization signal Sh and the vertical synchronization The period of the signal Sv also changes at the same rate, and therefore it is possible to reliably prevent erroneous measurements due to fluctuations in the signal period. However, the purpose of the present invention can be sufficiently achieved even with a configuration in which the clock signal that forms the basis of the horizontal and vertical signals and the clock signal sent to the counting circuit 25 are generated by separate clock generation circuits. Therefore, an apparatus having such a configuration is also included within the scope of the present invention.

As explained above, according to the magnetic head position measuring device of the present invention, the deviation of the mounting position of the magnetic head from the reference position can be measured in a very short time and with simple work. Further, since the measurement results can be directly read as numerical values, it can be immediately determined whether the deviation in the mounting position is within the allowable error range. Furthermore, since the first and second vertical lines are moved respectively, the mounting position of the magnetic head can always be accurately measured, regardless of whether there is any deviation in the mounting position of the imaging device. I can do it. Further, even if the image pickup device is mounted incorrectly, there is no need to readjust the leakage to the correct position, and the effort can be saved.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the magnetic head position measuring device according to the present invention, and FIG. 2 is a bottom view of the rotating head. 2... Imaging device, 3... Screen display device, 4...
Screen, 5...First vertical line, 6...Second vertical line, 7...Display device, 8...Upper cylinder (head support), 9...Magnetic head, 16...Clock generation circuit, 17...Synchronization signal generation circuit, 18...
Vertical line generation circuit (reference line generation circuit), 19...first adjuster, 20...second adjuster, 24...distance calculation circuit.

Claims (1)

[Claims for Utility Model Registration] (a) A clock generation circuit that generates a clock signal; (b) A horizontal synchronization signal based on the clock signal;
(c) an imaging device that uses these horizontal synchronization signals and vertical synchronization signals as control signals; and (d) the number of clock signals using each of the horizontal synchronization signals as a starting point. When the number of clock signals reaches a number corresponding to the output of the first regulator whose output is variable, a first reference line signal for displaying the reference position of the magnetic head is generated, and the number of the clock signals is variable whose output is variable. a reference line generation circuit that generates a second reference line signal for displaying the actual mounting position of the magnetic head when the number corresponds to the output of the second regulator; (e) an output of the imaging device; (f) the number of clock signals between the first and second reference line signals, and the number of clock signals between the first and second reference line signals; a distance calculation circuit that calculates and outputs the actual distance corresponding to the first and second reference line signals from the actual distance corresponding to one cycle of the signal; (g) the output of this distance calculation circuit; 1. A magnetic head mounting position measuring device comprising a display device for displaying numerical values.