CN100401393C - Apparatus and method for measuring distance and oblique angle between optical pick-up device and storage media - Google Patents

Abstract

The present invention relates to an apparatus and method for measuring a distance and an oblique angle between an optical pick-up device and a storage medium. The present invention comprises a supporting seat which is formed on a light gathering component (an object lens), a wedge which is inserted into the supporting seat and is provided with a reflecting surface, and a detecting component which is used for detecting the distance and the oblique angle. The wedge makes beams which are irradiated to regions except the region of the light gathering component reflected. Thereby, the present invention has the advantages of the present invention can simultaneously show the functions of a common focus servo device and an oblique servo device, and timely track the absolute distance and the oblique angle between the object lens and the medium.

Description

The Apparatus for () and method therefor at distance and pitch angle between mensuration light picker and medium

(1) technical field

The invention relates to the Apparatus for () and method therefor of measuring distance and inclination between medium (disk) and collector lens in the HIGH-DENSITY OPTICAL STORAGE media system, especially form supporting seat about going up at optically focused parts (object lens), on supporting seat, insert chock (wedge) with plane of refraction, the light that shines beyond the optically focused component area is reflected, and utilize that detection part detects above-mentioned distance and inclination a kind of measure between light picker and medium apart from and the Apparatus for () and method therefor at pitch angle.

(2) background technology

Even to this day, the digitizing (digital) of dependence data (data), high capacity etc., storage medium are changed to disc (disk) by tape (tape), simultaneously, by improving the density of storage data on disc, improve the memory capacity of disc.

Therefore, in order to improve the storage density of high density compact disc, the distance (being the signal trace spacing) between signal trace is diminished.

, in the manufacturing process of this CD, in the injection moulding and hardening process of plastics, just error can take place here, thus, even in central punch, the phenomenon of deviation also can the generative center hole occurs.

Simultaneously, CD is followed the tracks of and is promptly allowed to correctly store according to the spacing of certain specification, but because deviation appears in center pit, the phenomenon of eccentric and disc tilt (tilt) therefore can occur.

Therefore, in optical disc eccentricity, when CD was rotated, the central shaft of driver was difficult to the tracking center of CD in full accord.

Therefore, want to read needed tracking signal and be difficult to, in CD and DVD mode, in order when eccentric situation takes place, also can to make light beam catch up with needed tracking all the time, and use the tracking servo device.

That is, above-mentioned tracking servo device generates and the corresponding electric signal of beam trajectory state, and serve as basic with this signal, will move to radius (radial) direction object lens and light picker body, and the correction light-beam position, thus correctly follow the tracks of.

On the other hand, if when light beam can't carry out correlation tracking, above-mentioned optical disc eccentricity phenomenon not only can take place, and the disc tilt phenomenon can take place.If like this, hardware problem can take place as the error that is taken place in it when CD being installed in the CD-ROM drive rotating shaft.That is, tracking taking place does not have correctly according to the consistent mistake of vertical direction with assembling.The state of this disc tilt is called as disc tilt (tilt).

In general, when storing and reading, optical disc memory must maintain horizontality with CD, but because the machine error of light picker and rotating shaft and the tolerance when installing, CD just can tilt to tangent line (Tangential below the is referred to as tangent line) direction of radius (radial: be also referred to as the secondary radius) direction and information trace.

Fig. 1 is the component drawings of normal optical storing/reading device.It is made up of following each several part: information stores is gone into optical storage medium CD 101 or therefrom read information, and CD institute beam reflected is converted to the built-in light picker 102 of optical detector 102a of electric signal; Include the inclination mistake detection device 106 that the push-pull signal that utilizes tangential direction detects tilt error signal, generate the servo fault generating apparatus 103 of servo error signal RF in the electric signal of from light picker, exporting; The trail-and-error signal that above-mentioned servo fault generating apparatus is generated detects next trail-and-error (TE) detection device 104; Focusing mistake (FE) detection device 105 that the focus signal that above-mentioned servo fault generating apparatus is generated detects; The tangent line that above-mentioned servo fault generating apparatus is generated is recommended the tangent line that rub-out signal detects and is recommended wrong detection device (wrong detection device promptly tilts) 106.

In order to control servomechanism, also must comprise following each several part: the Servocontrol device 108 (comprising: focusing, tracking, incline controller) that generates and export control signal by the signal that utilizes above-mentioned wrong detection device to detect; Control above-mentioned light picker according to the drive signal that above-mentioned Servocontrol device is exported, and the drive unit 109 (comprising: focusing, tracking, reclining drive device) of control servomechanism.

Fig. 2 is a display light storing/reading device pick-up pie graph.

As shown in the figure, it is made of following each several part: the laser diode (LD) 201 that produces LASER Light Source; The LASER Light Source that above-mentioned laser diode 201 is produced is converted to the collimation lens (CL) (collimator lens) 202 of directional light; The typing prism 203 that the directional light at any angle that is shone by above-mentioned collimation lens 202 is regulated; The directional light that is shone by above-mentioned typing prism 203 is carried out the polarisation optical splitter PBS (polarization beam splitter) 204 that polarisation is handled; The laser that carries out the polarisation processing is converted to λ/4 photographic plates (QWP) 205 of former polarisation laser; The light of incident is carried out the object lens 206 and the medium of optically focused--CD 207.

Along with optical storage technology to the densification trend development, light picker in aforesaid optical storage/fetch equipment all uses than the object lens that had bigger digital ring (numerical aperture:NA) in the past, or utilizes near field of light (near field) to develop.

Development along with this trend, focal length (workingdistance) between object lens and medium (CD 207) can shorten surely, simultaneously, the position of medium when confirming to drive, or light picker when operation because tilt etc., can make between object lens and accessory (mount) and medium (media) to clash.

Especially nearest, along with the variation (CD/DVD/BD etc.) of medium kind, because its mistake of inserting each other, thereby in rotation (swing) process of carrying out, just can clash in order to ensure servo (Servo) for the first time.

In order to prevent the generation of this phenomenon, when designing, must make the maximization of its operating distance, perhaps in order when clashing, to make the minimization of loss of object lens, and safety equipment are installed.But because can't The real time measure go out absolute distance between medium and object lens, therefore this method is invalid basically.

Simultaneously, though can utilize the indirect method (error signal) of adding an inclination (tilt) sensor to measure the inclination (tilt) of medium,, it exists the shortcoming that can only determine direction.

Simultaneously, when using high digital ring NA or near field of light technology such as (near fileld),, also need a kind ofly can measure the method that (monitoring) goes out distance and pitch angle between medium and object lens easily in order to protect light picker and to improve characteristics of signals.

(3) summary of the invention

Therefore, in order to address the above problem, the present invention just arises at the historic moment.The invention provides a kind of can The real time measure medium (CD) and collector lens (object lens) between the Apparatus for () and method therefor at distance and pitch angle between the mensuration light picker at absolute distance and pitch angle and medium.

Specifically,, on object lens, form a supporting seat, on supporting seat, insert and have the chock of plane of refraction, and have the parts that detect that can detect light that chock reflects with common focus servo device and oblique servo device function according to the present invention.

To achieve these goals, the distance and the equipment at pitch angle are made of following each several part between mensuration light picker of the present invention and medium: the optically focused parts that light is assembled; The supporting seat that contacts with above-mentioned optically focused parts and constitute; The refractive component of a pair of at least that on described supporting seat, forms with a refraction angle φ, in the heart distance is r in described optically focused parts center and the refractive component; Detect the light that described refractive component reflects, and the light that forms with the number corresponding with it detects parts; Above-mentioned optically focused parts, light detect parts when measuring distance and pitch angle between light picker and medium, obtain respectively earlier from the center of described refractive component to described detect the parts Detection Point apart from X1, X2 after, in the relational expression between X1, X2 substitution r and the φ, described relational expression is:

Mathematical expression 1

$\frac{\mathrm{SIN}(90+2\mathrm{\&theta;}-\mathrm{\&phi;})}{2\mathrm{COS\&theta;SIN}(\mathrm{\&phi;}-\mathrm{\&theta;})}\mathrm{<figure-callout\; id="1"\; label="X"\; filenames="C20041001055800162.png"\; state="\{\{state\}\}">X</figure-callout>}1=d+r\tan \mathrm{\&theta;}$

Mathematical expression 2

$\frac{\mathrm{SIN}(90-2\mathrm{\&theta;}-\mathrm{\&phi;})}{2\mathrm{COS\&theta;SIN}(\mathrm{\&phi;}-\mathrm{\&theta;})}X2=d-r\tan \mathrm{\&theta;}$

Wherein d be the optically focused parts center of light picker to the distance at medium reflecting surface center, according to the above-mentioned relation formula, obtain optically focused parts center to medium reflecting surface center apart from d and tiltangle.。

For example, above-mentioned refractive component can be the chock shape that plane of refraction tilts, and the number of refractive component can be in order to detect the inclination of radius and tangential direction (radial and tangential), and is provided with respectively more than one, forms a pair of.

According to the present invention, incide the point that light detects parts from the light that refractive component reflected, can be different according to the inclination of medium.

Simultaneously, according to the embodiment of the invention, the formation that refractive component and light detect parts also can be the ring-like form with certain angle.

Comprise following each step according to the method for measuring distance and tilting of the present invention: from light source output beam step; The light of light source output shines in the refractive component with a refraction angle (φ), detects the light step that parts detect institute's refraction/reflection; Obtain respectively from the refractive component center to detecting distance (X1, X2) step the parts Detection Point; With step in the relational expression between the refraction angle (φ) of distance (r) and refractive component between above-mentioned numerical value substitution optically focused parts of obtaining and refractive component, described relational expression is:

Mathematical expression 1

$\frac{\mathrm{SIN}(90+2\mathrm{\&theta;}-\mathrm{\&phi;})}{2\mathrm{COS\&theta;SIN}(\mathrm{\&phi;}-\mathrm{\&theta;})}\mathrm{<figure-callout\; id="1"\; label="X"\; filenames="C20041001055800162.png"\; state="\{\{state\}\}">X</figure-callout>}1=d+r\tan \mathrm{\&theta;}$

Mathematical expression 2

$\frac{\mathrm{SIN}(90-2\mathrm{\&theta;}-\mathrm{\&phi;})}{2\mathrm{COS\&theta;SIN}(\mathrm{\&phi;}-\mathrm{\&theta;})}X2=d-r\tan \mathrm{\&theta;}$

Wherein d is the distance of the optically focused parts center of light picker to medium reflecting surface center; According to the above-mentioned relation formula, obtain the step apart from d and tiltangle of optically focused parts center to medium reflecting surface center.

With reference to accompanying drawing,, just can know other characteristic of the present invention and purpose by embodiment is elaborated.

Effect of the present invention:

As mentioned above, the Apparatus for () and method therefor according to distance and pitch angle between mensuration light picker of the present invention and medium has following effect: the function that can embody common focus servo device and oblique servo device simultaneously.

Different with original servosystem, can the real-time tracing object lens and medium between absolute distance and angle of inclination.

Therefore, as the function of following the trail of absolute distance and angle of inclination, specifically it has and misplugs fashionable at medium (media), can prevent with object lens between conflict, when using multilayer medium (Multilayermedia), can confirm layer (layer), when using holographic photography medium (holography media), be applicable to the effect of multipleization at angle (angle).

For further specifying above-mentioned purpose of the present invention, design feature and effect, the present invention is described in detail below with reference to accompanying drawing.

(4) description of drawings

Fig. 1 is the component drawings of normal optical storing/reading device.

Fig. 2 is a display light storing/reading device pick-up pie graph.

Fig. 3 is the pie graph according to mensuration absolute distance of the present invention and pitch angle module.

Fig. 4 is a planimetric map of measuring absolute distance and pitch angle module structure drafting.

Fig. 5 shows according to embodiments of the invention figure.

Fig. 6 shows according to another embodiment of the present invention figure.

Fig. 7 is a process flow diagram of obtaining between medium and object lens distance and pitch angle according to of the present invention.

(5) embodiment

Embodiment to the Apparatus for () and method therefor at distance and pitch angle between mensuration light picker of the present invention and medium is elaborated below with reference to accompanying drawings.

Fig. 3 is the pie graph according to mensuration absolute distance of the present invention and pitch angle module.

As shown in the figure, the present invention includes following each several part: optically focused parts-object lens 301 that light is assembled; The supporting seat (Hard aperture) 302 that contacts with above-mentioned optically focused parts and constitute; Refractive component-the chock (wedge) 303 of a pair of at least that on above-mentioned supporting seat, forms with certain refraction angle; Detect the light that above-mentioned refractive component reflects, and the light that forms with the number corresponding with it detects parts (line detector array) 304.

Above-mentioned refractive component can be chock 303 shapes that plane of refraction tilts, and the number of refractive component can be in order to detect the inclination of radial direction (radial) and tangential direction (tangential), and the formation a pair of is set respectively more than one.According to the present invention, incide the point that light detects parts from the light that refractive component reflected, can be different according to the inclination of medium.

Below formation and the ruuning situation of Fig. 3 are launched explanation.

Formation of the present invention is applicable to the object lens position of light picker.As long as hold the degree that original focusing/oblique servo (focal/tilt servo) leaves desired position, in general independently to install and compare with existing servomechanism, it can embody two kinds of functions simultaneously, and can its absolute figure of real-time tracing.

As shown in Figure 3 and Figure 4, utilize the light shine the accessory (mount) beyond the object lens effective aperture, chock 303 is installed in the accessory (mount), and make light have special angle to shine out.

When the light of incident arrives medium (medium) reflecting surface, as shown in Figure 5, the light that reflects according to the pitch angle of medium has nothing in common with each other, position numerical value according to reflected light arrival both sides 1 dimension optical sensors (linedetector sensor) just can calculate absolute distance and pitch angle between medium and object lens.

In general, in order to know the inclination of light/tangent line (Radial/Tangential) direction, and chock (wedge) and 1 dimension sensor have been installed in 4 positions, but, as shown in Figure 6, form chock, and correspondingly constitute light and detect sensor with ring-like shape.

As above institute's simple declaration is such, and Fig. 4 is a planimetric map of measuring absolute distance and pitch angle module structure drafting.

Its basic comprising is identical with above-mentioned Fig. 3, and the object lens 401 that light is assembled because Fig. 4 shows now is the state that medium 405 not have inclination, detect detected chock 403 refraction points of parts optical sensor 404 and medium incident, reflection spot is identical.

Fig. 5 shows according to specific embodiments of the invention figure.

Here, r refers in object lens center and the chock distance in the heart.Because medium are in heeling condition, (X1 X2) has nothing in common with each other so detect the point that parts (line detector array) are measured at each chock center.What simultaneously, θ represented is the pitch angle of medium.

Below with reference to last figure, to describing according to ruuning situation of the present invention.

The formation of the equipment at absolute distance and pitch angle as shown in Figure 3 and Figure 4 between mensuration light picker proposed by the invention and CD.

Entire equipment is installed in the object lens part of light picker as shown in Figure 2.As shown in Figure 4, accessory outside the object lens effective aperture (mount) part 4 zones (R/T direction) are penetrated with a hole 402, and insert a chock (wedge) 403 with same tilt degree.

At this moment, shine the outer direction of object lens fully by the caused refracted ray in dip plane.The plane of incidence of light is vertical, and has certain angle in the back.

Be mapped to the position that medium reflecting surface back reflection returns in illumination optical sensor 404 is installed, at this moment, the light that optical sensor 404 can detect each position respectively and reflected.(for example: CCD array)

As mentioned above, the formation of the equipment at absolute distance and pitch angle will describe all light paths as shown in Figure 2 below between foundation mensuration light picker of the present invention and CD.

The light beam with S-pol (vertically) source polarisation that produces from LD201 passes through collimation lens (collimator) 202 lens and typing prism 203, is calibrated (collimate).

This light beam is reflected by PBS204, light path is changed 90 °, through QWP205, become the source polarisation, key light (main beam) by object lens 401 optically focused to medium 405 storage/reflectings surface, at this moment, chock (wedge) 403 retainings that the catoptrical part with diameter bigger than object lens effective aperture is installed in object lens accessory (mount) and are delivered to the reflecting surface of medium 405 outside.The light that is reflected arrives the ad-hoc location of optical sensor 404, and is detected.

At this moment, as shown in Figure 5, if the object lens center is r to the chock radius centered, the chock sensor is respectively X1 and X2 to the distance that optical sensor detects the position, and the object lens center is d to the distance at medium reflecting surface center, and the distance between object lens gabarit and medium reflecting surface is respectively d1, d2, the refraction angle of chock (wedge) is φ, and the angle vertical with the optical axis of medium (tilt angle) is θ, just can be with following digital the expression.

[mathematical expression 1]

$\frac{\mathrm{SIN}(90+2\mathrm{\&theta;}-\mathrm{\&phi;})}{2\mathrm{COS\&theta;SIN}(\mathrm{\&phi;}-\mathrm{\&theta;})}\mathrm{<figure-callout\; id="1"\; label="X"\; filenames="C20041001055800162.png"\; state="\{\{state\}\}">X</figure-callout>}1=d+r\tan \mathrm{\&theta;}$

[mathematical expression 2]

$\frac{\mathrm{SIN}(90-2\mathrm{\&theta;}-\mathrm{\&phi;})}{2\mathrm{COS\&theta;SIN}(\mathrm{\&phi;}-\mathrm{\&theta;})}X2=d-r\tan \mathrm{\&theta;}$

In the above-mentioned relation formula, X1, X2 are the numerical value of measuring, and r and φ are known numerical value, therefore just can the needed object lens of real-time tracing and medium between absolute distance d and pitch angle (tilt angle) (θ).

If utilize this numerical value, not only can carry out focus servo (focal servo) and oblique servo (tilt servo), and can prevent by mispluging into caused conflict, if multilayer medium (multipayer media) can be confirmed layer (layer), and be applicable to measuring multipleization of volume storage (volumetric storage) technology-holographic photography (angle of holographic media).

Fig. 6 shows according to another embodiment of the present invention figure.

That is, form the chock 602 of ring-like form, and can constitute corresponding with it optical sensor 604 with certain angle in accessory 602 back of object lens 601.

Fig. 7 is a process flow diagram of obtaining between medium and object lens distance and pitch angle according to of the present invention.

S701 is from light source LD output light.

Whether S702, S707 judge whether this light incides in the refractive component-chock with certain angle, detect refraction/reflection light-sensor and detect, if do not detect, just focus on and the tracking servo process according to original servo mode.

S703, if this light incides in the refractive component-chock with certain angle, the detector array that can detect the light that medium reflect is arranged (line detector array), just receive light.

S704, at this moment, obtain respectively distance between the Detection Point that detects parts that refractive component center to above-mentioned detector array arranges (X1, X2).

S705, S706, in the relational expression between the refraction angle (φ) of distance (r) and refractive component between above-mentioned numerical value substitution optically focused parts of obtaining and refractive component, according to the above-mentioned relation formula, obtain distance (d) and pitch angle (θ) between optically focused parts and medium (CD), flow process finishes.

As mentioned above, the invention relates to Apparatus for () and method therefor: go up at optically focused parts (object lens) and form supporting seat with following function, on supporting seat, insert chock (wedge) with plane of refraction, the light that shines beyond the optically focused component area is reflected, and utilize detection part to detect above-mentioned distance and inclination.

Utilize this method, under the situation of having known between medium and object lens distance and pitch angle, not only can carry out basic servosignal (servo signal), and if multilayer medium (multipayer media) can carry out the selection (layer selection) of layer, if measure under the situation of volume recording-media (volumetric recording media), be applicable to multipleization of angle (angle) of holographic photography (holographic recording) technology.

By above-mentioned description, the related work personnel can carry out various change and modification fully in the scope that does not depart from this invention technological thought.

Promptly, under the situation of having known between medium and object lens distance and pitch angle, not only can carry out basic servosignal (servo signal), and if multilayer medium (multipayer media) can carry out the selection (layer selection) of layer, if measure under the situation of volume recording-media (volumetric recording media), be applicable to multipleization of angle (angle) of holographic photography (holographicrecording) technology.

Those of ordinary skill in the art will be appreciated that, above embodiment is used for illustrating the present invention, and be not to be used as limitation of the invention, as long as in connotation scope of the present invention, all will drop in the scope of claims of the present invention variation, the modification of the above embodiment.

Claims (8)

1. equipment of measuring between light picker and medium distance and pitch angle is characterized in that comprising:

The optically focused parts that light is focused on;

The supporting seat that contacts with described optically focused parts and constitute;

The refractive component of a pair of at least that on described supporting seat, forms with a refraction angle φ, in the heart distance is r in described optically focused parts center and the refractive component;

Detect the light that described refractive component reflects, and the light that forms with the number corresponding with it detects parts;

Above-mentioned optically focused parts, light detect parts when measuring distance and pitch angle between light picker and medium, obtain respectively earlier from the center of described refractive component to described detect the parts Detection Point apart from X1, X2 after, in the relational expression between X1, X2 substitution r and the φ, described relational expression is:

Mathematical expression 1

$\frac{\mathrm{SIN}(90+2\mathrm{\&theta;}-\mathrm{\&phi;})}{2\mathrm{COS\&theta;SIN}(\mathrm{\&phi;}-\mathrm{\&theta;})}X1=d+r\tan \mathrm{\&theta;}$

Mathematical expression 2

$\frac{\mathrm{SIN}(90-2\mathrm{\&theta;}-\mathrm{\&phi;})}{2\mathrm{COS\&theta;SIN}(\mathrm{\&phi;}-\mathrm{\&theta;})}X2=d-r\tan \mathrm{\&theta;}$

Wherein d be the optically focused parts center of light picker to the distance at medium reflecting surface center, according to the above-mentioned relation formula, obtain optically focused parts center to medium reflecting surface center apart from d and tiltangle.

2. the equipment at distance and pitch angle between mensuration light picker as claimed in claim 1 and medium is characterized in that:

Described refractive component is the chock shape that plane of refraction tilts.

3. the equipment at distance and pitch angle between mensuration light picker as claimed in claim 2 and medium is characterized in that:

The number of described refractive component can be in order to detect the pitch angle of radial direction and tangential direction, and is provided with respectively more than one, forms a pair of.

4. the equipment at distance and pitch angle between mensuration light picker as claimed in claim 1 and medium is characterized in that:

Incided the point that light detects parts by the light that described refractive component reflected, can be different according to the pitch angle of medium.

5. the equipment at distance and pitch angle between mensuration light picker as claimed in claim 1 and medium is characterized in that:

It is that detector array is arranged that described light detects parts.

6. the equipment at distance and pitch angle between mensuration light picker as claimed in claim 1 and medium is characterized in that:

The formation that described refractive component and light detect parts is the ring-like form with certain angle.

7. a method of measuring between light picker and medium distance and pitch angle is characterized in that comprising the steps:

Step from the light source output beam;

The light of light source output shines in the refractive component with certain refraction angle φ, detects the step that parts detect the light of institute's refraction/reflection;

Obtain respectively from the refractive component center to the step that detects the parts Detection Point apart from X1, X2;

With between the above-mentioned numerical value X1 that obtains, X2 substitution optically focused parts center and refractive component center apart from the step in the relational expression between r and the described refraction angle φ, described relational expression is:

Mathematical expression 1

$\frac{\mathrm{SIN}(90+2\mathrm{\&theta;}-\mathrm{\&phi;})}{2\mathrm{COS\&theta;SIN}(\mathrm{\&phi;}-\mathrm{\&theta;})}X1=d+r\tan \mathrm{\&theta;}$

Mathematical expression 2

$\frac{\mathrm{SIN}(90-2\mathrm{\&theta;}-\mathrm{\&phi;})}{2\mathrm{COS\&theta;SIN}(\mathrm{\&phi;}-\mathrm{\&theta;})}X2=d-r\tan \mathrm{\&theta;}$

Wherein d is the distance of the optically focused parts center of light picker to medium reflecting surface center;

According to the above-mentioned relation formula, obtain the step apart from d and tiltangle of optically focused parts center to medium reflecting surface center.

8. the method at distance and pitch angle between mensuration light picker as claimed in claim 7 and medium is characterized in that also comprising:

After the step of light source output beam, judge whether light incides the refractive component step with certain angle.

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