CN1530942A - Method for determining angle of recording/reading of CD pickup - Google Patents

Abstract

The present invention is a method for determining an operating angle of an optical reading and writing head of an optical driver, which is used in a jitter checking device comprising a fixture for simulating and adjusting the tilt angle of the optical reading and writing head and a jittering instrument for measuring the jitter value of the optical reading and writing head at the different tilt angles. In this method, the measured points are reduced to five by means of the empirical formula, and as the basis for adjusting the operating tilt angle of the optical reading and writing head, the minimum jitter value and the optimum tilt angle of the optical reading and writing head can be calculated rapidly without the necessity of performing the zero adjustment of the radial and tangential tilt angles respectively.

Description

The method of CD-ROM drive optical read-write head working determining angle

Technical field

The invention relates to a kind of method of CD-ROM drive optical read-write head working determining angle, refer to that especially a kind of inclination angle that does not need radially to reach tangential direction makes zero respectively, can calculate the minimum Jitter value and the optimum angle of incidence of optical read-write head.

Background technology

The optical read-write head 1a of CD-ROM drive often because of the error in accessory size and the assembling, causes the light path (Optical Path) of this optical read-write head 1a to be not orthogonal to reference plane 2a, and forms an inclination angle [theta] (as shown in Figure 1) in manufacture process; Therefore, in known technology, the manufacturing plant of optical read-write head then needs respectively to measure the relation at its jitter value (Jitter value) and inclination angle at (radial) and tangent line (tangential) direction radially, and therefrom calculate this optical read-write head 1a radially with the optimum angle of incidence of tangential direction.

Further, Jitter value and ultimate value thereof all have clear and definite regulation in the standard criterion that CD-ROM and DVD (Digital Video Disc) industry are announced, the Jitter value mainly contains two phenomenons take place: the one, and from the mistiming (T that measures between between data and clock pulse ₁And T ₂), its computing method Jitter=T in cd-rom player ₁-T ₂, and in DVD player Jitter=(T ₁-T ₂)/T ₁(as shown in Figure 2), another is to measure pulsewidth (or the measurement of the recurrence interval of MO), and the measurement of this pulse width mainly is to be used for assessing the disc storage medium; Thus, from existing experimental formula, Jitter value and inclination angle have following relation: Jitter (x)=ax ²+ bx+c and Jitter (y)=ay ²+ by+c, wherein x represents inclination angle radially, and y represents the inclination angle of tangential direction, and a, b and c represent unknown constant; When calculating Jitter (x), the inclination angle of tangential direction need be made flyback action earlier, and the inclination angle of measuring radially for three times, and when calculating Jitter (y), then inclination angle radially need be made flyback action earlier, inferior repeatedly inclination angle of measuring tangential direction.

In view of the above, by Jitter (x)=ax ²+ bx+c and Jitter (y)=ay ²+ by+c two curvilinear equation formulas as can be known, measure 3 curvilinear equation formulas that can determine this direction at single direction (radially or tangential direction), and try to achieve this direction curve minimum point (as shown in Figures 3 and 4, the Jitter value that gets final product minimumly), and then obtain the optimum angle of incidence of this direction, therefore, then need measure six points at least if will finish radially calculating with the optimum angle of incidence of tangential direction, and when measuring the inclination angle of a certain direction, must earlier flyback action be made at the inclination angle of other direction.

In sum, see also shown in Figure 5ly, it is the method for known CD-ROM drive optical read-write head working determining angle, by among the figure as can be known this method need expend many times and unnecessary measurement action.

Therefore, the present invention proposes a kind of reasonable in design and effectively improve the method for above-mentioned defective.

Summary of the invention

Fundamental purpose of the present invention, provide a kind of method of CD-ROM drive optical read-write head working determining angle, it utilizes quadric experimental formula, order is measured quantity and is reduced to 5 points, and need not be made zero respectively in the inclination angle that radially reaches tangential direction, can calculate the minimum Jitter value and the optimum angle of incidence of this optical read-write head apace.

In order to reach above-mentioned purpose, the present invention provides a kind of method of CD-ROM drive optical read-write head working determining angle, and it is applied to the shake pick-up unit of optical read-write head, and this device comprises anchor clamps, adjusts the inclination angle of this optical read-write head in order to emulation; And being arranged at flutter meter on these anchor clamps, this flutter meter can detect the jitter value of this optical read-write head in different angle; This method comprises the following steps: to utilize quadric experimental formula Z=ax ²+ by ²+ cx+dy+e, and cooperate this shake pick-up unit to measure; Measure 5 points arbitrarily, and obtain the inclination angle (x of five groups of optical pickups ₁, y ₁), (x ₂, y ₂), (x ₃, y ₃), (x ₄, y ₄) and (x ₅, y ₅); List these five groups of inclination angles and corresponding Jitter value (Z ₁, Z ₂, Z ₃, Z ₄And Z ₅) set of simultaneous equations; Separate this set of simultaneous equations, in the hope of a ₁, b ₁, c ₁, d ₁And e ₁Obtaining the surface equation formula is Z=a ₁x ²+ b ₁y ²+ c ₁X+d ₁Y+e ₁Calculate this surface equation formula, and try to achieve the minimum Jitter value and the optimum angle of incidence of this optical read-write head; And in data input one bar code of Jitter value that should minimum, so that as the foundation at the work inclination angle of adjusting optical read-write head.

Reach technology, means and the effect that predetermined purpose is taked in order further to set forth the present invention, see also following about detailed description of the present invention and accompanying drawing, purpose of the present invention, feature and characteristics, can get one thus gos deep into and concrete understanding, yet appended graphic only for reference and explanation usefulness is not to be used for the present invention is limited.

Description of drawings

Fig. 1 is the synoptic diagram that the light path of known optical read-write head is not orthogonal to reference plane;

Fig. 2 is the synoptic diagram of known generation jitter phenomenon;

Fig. 3 is the coordinate diagram of the quafric curve of known radial rake;

Fig. 4 is the coordinate diagram of the quafric curve at known tangential direction inclination angle;

Fig. 5 is the process flow diagram of the method for known CD-ROM drive optical read-write head working determining angle;

Fig. 6 is the synoptic diagram that the present invention is used for the shake pick-up unit of optical read-write head;

Fig. 7 is the process flow diagram of the method for CD-ROM drive optical read-write head working determining angle of the present invention;

Fig. 8 is quadric coordinate diagram that the present invention radially reaches tangential direction.

Embodiment

See also shown in Figure 6, it is used for the synoptic diagram of the shake pick-up unit 2 of optical read-write head for the present invention, include anchor clamps, being used for emulation adjusts the inclination angle (as the θ among Fig. 6) of this optical read-write head 1, an and flutter meter 21, it is arranged on these anchor clamps, and this flutter meter 21 is to detect the jitter value of this optical read-write head 1 in different angle; Seeing also shown in Figure 7ly, is the method for this CD-ROM drive optical read-write head working determining angle, and it comprises the following steps:

(1) provides a surface equation formula Z=ax ²+ by ²+ cx+dy+e, wherein x is a radial rake, and y is the tangential direction inclination angle, and Z is that (x y) be worth, and a, b, c, d and e is unknown constant to Jitter.

(2) adjust this anchor clamps angle five times arbitrarily, and obtain the inclination angle (x of five groups of optical pickups ₁, y ₁), (x ₂, y ₂), (x ₃, y ₃), (x ₄, y ₄) and (x ₅, y ₅); And utilize this flutter meter to measure Jitter value (Z respectively simultaneously with respect to these five groups of inclination angles ₁, Z ₂, Z ₃, Z ₄And Z ₅).

(3) list the set of simultaneous equations of these five groups of inclination angles and corresponding Jitter value respectively, and obtain a matrix equation formula, as follows:

$\left[\begin{array}{ccccc}{x_1}^2& {y_1}^2& x_1& y_1& 1\\ {x_2}^2& {y_2}^2& x_2& y_2& 1\\ {x_3}^2& {y_3}^2& x_3& y_3& 1\\ {x_4}^2& {y_4}^2& x_4& y_4& 1\\ {x_5}^2& {y_5}^2& x_5& y_5& 1\end{array}\right]\left[\begin{array}{c}a\\ b\\ c\\ d\\ e\end{array}\right]=\left[\begin{array}{c}{Z}_1\\ Z_2\\ Z_3\\ Z_4\\ Z_5\end{array}\right]$

(4) separate this matrix equation formula, try to achieve a ₁, b ₁, c ₁, d ₁And e ₁Be known constant.

(5) with this known constant a ₁, b ₁, c ₁, d ₁And e ₁In generation, returned this curvilinear equation formula Z=ax ²+ by ²(be a=a among the+cx+dy+e ₁, b=b ₁, c=c ₁, d=d ₁And e=e ₁), be Z=a and obtain this surface equation formula ₁x ²+ b ₁y ²+ c ₁X+d ₁Y+e ₁

(6) utilize this surface equation formula Z=a ₁x ²+ b ₁y ²+ c ₁X+d ₁Y+e ₁, obtaining its quadric minimum point, promptly minimum Jitter value, this minimum point are exactly the optimum angle of incidence (as shown in Figure 8) that radially reaches tangential direction.

(7) in should minimum Jitter value data input one bar code, with as the foundation of adjusting optical read-write head work inclination angle.

In sum, the present invention is a kind of quadric experimental formula of utilizing in fact, and order measurement quantity is reduced to 5 points, so that make the improving productivity 17% of optical read-write head, and make zero respectively in the inclination angle that does not need radially to reach tangential direction, can calculate the minimum Jitter value and the optimum angle of incidence of this optical read-write head apace; And utilize above-mentioned set of simultaneous equations and make Z ₁=Z ₂=Z ₃=Z ₄=Z ₅, and set the upper limit of Jitter value, and just can try to achieve the common factor of each light path surface equation formula, this common factor is exactly the zone that each light path system all can normally write, read.

The above, only be the detailed description of one of best specific embodiment of the present invention and graphic, and feature of the present invention is not limited thereto, be not in order to restriction the present invention, all scopes of the present invention should be as the criterion with following claims scope, all closing in the embodiment of the spirit variation similar of the present patent application claim with it, all should be contained in the category of the present invention, any those of ordinary skill in the art is in the field of the invention, can change easily or modify, these also all should be encompassed in the scope of claims.

Claims (1)

1, a kind of method of CD-ROM drive optical read-write head working determining angle is applied to the shake pick-up unit of optical read-write head, and described device includes anchor clamps, adjusts the inclination angle of described optical read-write head in order to emulation; And being arranged at flutter meter on the described anchor clamps, described flutter meter is to detect the jitter value (Jitter value) of described optical read-write head in different angle; It is characterized in that the method for described CD-ROM drive optical read-write head working determining angle comprises the following steps:

(1) utilizes quadric experimental formula: Z=ax ²+ by ²+ cx+dy+e, and cooperate described shake pick-up unit to measure;

(2) measure 5 points arbitrarily, and obtain the inclination angle (x of five groups of optical pickups ₁, y ₁), (x ₂, y ₂), (x ₃, y ₃), (x ₄, y ₄) and (x ₅, y ₅);

(3) list described five groups of inclination angles and corresponding Jitter value (Z ₁, Z ₂, Z ₃, Z ₄And Z ₅) set of simultaneous equations;

(4) separate described set of simultaneous equations, in the hope of a ₁, b ₁, c ₁, d ₁And e ₁

(5) with a ₁, b ₁, c ₁, d ₁And e ₁In generation, returned the experimental formula of step (1), and obtaining the surface equation formula is Z=a ₁x ²+ b ₁y ²+ c ₁X+d ₁Y+e ₁

(6) the surface equation formula of calculation procedure (5), and try to achieve the minimum Jitter value and the optimum angle of incidence of described optical read-write head; And

(7) in data input one bar code with described minimum Jitter value, so that the foundation at the work inclination angle of optical read-write head is adjusted in conduct.

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