JP2505761Y2 - Optical disk inspection device calibration reference plate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention provides an optical disc inspection apparatus for measuring various physical properties of an optical disc, such as laser light reflectance and transmittance, and plate thickness. The present invention relates to improvement of a reference plate used for system calibration.

More specifically, the present invention relates to a configuration of a reference plate that is easy to set a value as a reference for calibration for a plurality of standard sample pieces.

[Conventional technology]

Generally, in the optical disc inspection apparatus, the measurement system is calibrated before measuring various characteristics of the optical disc. There are various methods for this calibration, but using a standard sample with a known value allows you to calibrate the entire measurement system including the detector and electrical circuit at once. It's convenient.

[Problems to be solved by the device]

However, in such a calibration method, in order to obtain a calibration curve by interpolating from several measurement points, several kinds of standard samples are prepared, and these standard samples are sequentially placed above the optical head (laser light irradiation position). ) Must be set correctly and it is not easy to exchange the standard sample. A method of using an already-measured optical disc as a standard sample is also conceivable, but when a stationary optical disc is irradiated with laser light,
The heat of the laser beam melts or oxidizes the metal film, which changes the reflectance or the transmittance. For this reason, the optical disk is rotated, but there are few optical disks whose reflectance and the like are uniform over the entire surface, and it is difficult to obtain an accurate reference value.
Further, the pricing for the standard sample is usually performed using parallel laser light. This is because it is difficult to accurately measure the power of the emitted light and the power of the reflected light by using the converged laser light. Therefore, if there is reflection on the surface of the standard sample, accurate pricing cannot be performed.

The present invention eliminates the drawbacks of the conventional device as described above, and allows a plurality of standard samples to be set accurately on the upper part of the optical head one after another, and the reflectance and the like can be improved even when the temperature rises due to laser light irradiation. Never change,
Moreover, it is an object of the present invention to realize a reference plate for calibrating an optical disk inspecting device, which can perform accurate pricing for a standard sample, with a simple structure.

[Means for solving the problem]

The optical disc inspection apparatus calibration reference plate of the present invention has a reflective film or a transmissive film made of a dielectric multilayer film formed on one surface of a glass substrate having the same plate thickness as an ordinary optical disk and antireflection on the other surface. A plurality of standard sample pieces each having a film formed thereon and set to a predetermined reference value, and a clamp portion that is commonly clamped by a clamp mechanism of an optical disc are arranged on the same circumference. And a substrate unit for holding the plurality of standard sample pieces such that the position of the reflection film surface and the height from the clamp surface match the recording film surface of an ordinary optical disk clamped by the clamp mechanism. It was done.

[Action]

In this way, by arranging a plurality of standard sample pieces on the same circumference of the substrate part and providing a clamp part similar to an optical disk on this substrate part, a plurality of standard sample pieces can be mounted on a special jig or the like. It can be clamped by the same clamping mechanism as the optical disc without using it, and any standard sample piece can be set on the upper part of the optical head simply by rotating the substrate part. Moreover, since the area of each standard sample piece is small, the uniformity is excellent.
Further, when a plurality of standard sample pieces are held so that the positions of the reflective film surface or the transmissive film surface and the height from the clamp surface coincide with the recording film surface of an ordinary optical disc clamped by the clamp mechanism, Since the sample piece is always held at the same height as the optical disc, the calibration can be performed under the condition closer to the actual measurement state. Furthermore, if the reflective film or the transmissive film of the standard sample piece is formed of a dielectric multilayer film, it is possible to realize a standard sample piece that is resistant to heat and whose reflectance or the like does not change even when irradiated with laser light. it can. In addition, if an antireflection film is formed on the laser light incident surface of the standard sample piece, the reflected light from the substrate surface may enter the light receiving element even when parallel light is used for pricing. Instead, accurate pricing can be performed according to the reflectance of the reflective film.

〔Example〕

Hereinafter, a reference plate for calibrating an optical disc inspection apparatus according to the present invention will be described with reference to the drawings.

FIG. 1 is a plan view showing an embodiment of a calibration reference plate for an optical disk inspection apparatus according to the present invention, and FIG. 2 is a sectional view thereof. In the figure, S0 to S11 are standard sample pieces each set to a predetermined reference value, 1 is a substrate portion that holds the standard sample pieces S0 to S11 on the same circumference, and 2 is provided at the center of the substrate portion 1. The clamp portion 21 is a clamp surface that comes into contact with a turntable that rotates the optical disc in the clamp portion 2. The standard sample pieces S0 to S11 have a glass substrate 31 having a plate thickness t equal to that of an ordinary optical disc, a reflective film or a transmissive film 32 made of a dielectric multilayer film formed on one surface of the glass substrate 31, and a glass substrate 31 on the other surface. The antireflection film 33 is formed.
The substrate portion 1 is a recording film when the standard sample pieces S0 to S11 are placed with the reflective film surface or the transmissive film surface 32 side facing up, and the height of the film surface from the clamp surface 21 is a clamp in an ordinary optical disc. Holds to match the height of the surface. For example, if the optical disc is of a type in which the substrate portion is directly clamped, the height of the recording film surface is equal to the plate thickness, so the standard sample pieces S0 to S11 are clamped at the bottom surface as shown in the figure. Held to match surface 21. If the optical disk has a clamping hub, the heights of the standard sample pieces S0 to S11 are also determined in consideration of the thickness of the hub.

FIG. 3 is a cross-sectional view showing an example of forming standard sample pieces S0 to S11. As shown in the drawing, the reflective film and the transmissive film 32 are formed of a dielectric multilayer film, and the reflectance or the transmittance is controlled according to the number of layers, and a predetermined value is set. As the material of the dielectric multilayer film, for example, titanium oxide (TiO ₂ ) and silicon oxide (SiO ₂ ) are used. In addition, in the substrate portion 1, the sample piece is not provided at the position where the reflectance is 0% and the position where the transmittance is 100%, which is transparent. The antireflection film 33 is formed on the surface (lower surface) of the substrate 1 on which the laser light is incident.

In the reference plate configured as described above, only the substrate unit 1 is attached to the clamp mechanism of the optical disc inspection apparatus using the clamp unit 2, and any standard sample piece is used without using a special jig or the like. S0 to S11 can be set on top of the optical head. In addition, each standard sample piece S0 ~ S11
The area is small, so it has excellent uniformity. Furthermore, since the dielectric multilayer film forming the reflective film or the transmissive film 32 is resistant to heat, even if the temperature of the film rises due to the irradiation of laser light, it may melt or the reflectance may change. Absent. The glass substrate 31 is also stable to high temperatures. Further, since the antireflection film 33 is formed on the surface on which the laser light is incident, there is no reflected light generated on the substrate surface, and accurate pricing can be performed.

FIG. 4 is a block diagram showing a state in which the reference plate of the present invention is attached to an optical disc inspection apparatus. The figure exemplifies the calibration operation in the reflectance measurement of the optical disk. In the figure, the same parts as those in FIGS. 1 and 2 are designated by the same reference numerals. Reference numeral 4 is a clamp mechanism for the optical disk in the optical disk inspection apparatus, 41 is its turntable, and 5 is an optical head. The optical head 5 converges the laser light emitted from the laser light source 51, the optical isolator 52, and the laser light source 51, which emits a constant amount of laser light, and the standard sample piece S0.
~ S11 objective lens 53 for focusing on the reflective film surface, photosensor 54 for detecting reflected light from standard sample pieces S0-S11 via optical isolator 52, amplifier 55 for amplifying the output of photosensor 54, etc. It is composed by.

During such a calibration operation, by simply rotating the substrate unit 1, any standard sample piece S0 to S11 can be moved to the optical head 5
Can be set on top of. Therefore, by plotting the relationship between the values of the standard sample pieces S0 to S11 and the measurement output So at this time and interpolating between these measurement points, the electrical system of the optical system such as the objective lens 53, the photosensor 54, the amplifier 55, etc. A calibration curve for the entire measurement system including the circuit system can be obtained at one time. Further, since the height of the reflection film surface of each of the standard sample pieces S0 to S11 is formed to be equal to the height of the recording film surface of a normal optical disc, the distance between the optical head 5 and the reflection film 32 is the same as that when the optical disc is measured. Therefore, the calibration operation can be performed under the conditions close to those at the time of actual measurement, such as the state of the focus servo.

In the above description, the calibration operation at the time of measuring the reflectance of the optical disk is illustrated, but even when the measurement items are changed, the mounting method of the reference plate does not change, and the desired standard sample pieces S0 to S11 are set. Can be set easily. Further, as the optical head 5, a type of irradiating the laser beam from the lower side of the optical disk is exemplified, but conversely, there is also a type of irradiating the laser beam from the upper side of the optical disk. In such a case, since the position of the recording curtain surface of the optical disc is on the lower side of the disc, the position and height of the reflective film surface or the transmissive film surface of the reference plate are also changed accordingly.

[Effect of device]

As described above, in the optical disc inspection apparatus calibration standard plate of the present invention, a reflective film or a transmissive film made of a dielectric multilayer film is formed on one surface of a glass substrate having the same plate thickness as a normal optical disc. A plurality of standard sample pieces each having an antireflection film formed on the other surface and set to a predetermined reference value, and a clamp portion commonly clamped by a clamp mechanism of an optical disk are provided. A substrate unit arranged on the circumference and holding the plurality of standard sample pieces such that the position of the reflection film surface thereof and the height from the clamp surface coincide with the recording film surface of an ordinary optical disk clamped by the clamp mechanism. Since it is equipped with, it is possible to clamp multiple standard sample pieces by a clamp mechanism common to the optical disc without using a special jig. Can, only by rotating the substrate section,
Arbitrary standard sample pieces can be set accurately on top of the optical head one after another, and the reflectance does not change even when the temperature rises due to laser light irradiation. Therefore, it is possible to realize a reference plate for calibrating an optical disc inspection device capable of performing accurate pricing with a simple configuration.

[Brief description of drawings]

1 and 2 are a structural view and a sectional view showing an embodiment of a reference plate for calibrating an optical disk inspecting apparatus of the present invention, and FIG. 3 is a sectional view showing an example of forming standard sample pieces S0 to S11. FIG. 1 is a block diagram showing an example of a state in which the reference plate of the present invention is attached to an optical disk inspection device. S0 to S11: standard sample piece, 1 ... substrate part, 2 ... clamp part, 31 ... glass substrate, 32 ... reflective film or transmissive film,
33 ... Antireflection film, 4 ... Clamping mechanism, 5 ... Optical head.

Claims (1)

(57) [Scope of utility model registration request] 1. A glass substrate having a plate thickness equal to that of an ordinary optical disk is provided with a reflection film or a transmission film made of a dielectric multilayer film on one surface and an antireflection film is formed on the other surface of the glass substrate to a predetermined standard. A plurality of standard sample pieces that have been assigned a value and a clamping part that is commonly clamped by the optical disc clamping mechanism are arranged on the same circumference, and the plurality of standard sample pieces are A reference plate for calibrating an optical disk inspecting device, comprising: a substrate portion for holding the position of the reflection film surface and the height from the clamp surface so as to match the recording film surface of an ordinary optical disk clamped by the clamp mechanism. .