JP2003131113A - Reference position adjusting device, optical device and optical device - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To always accurately determine the reference position of a light shield or an optical component. SOLUTION: The light-emitting means is provided with a light-emitting means, a light-receiving means opposed to the light-emitting means, and a level detecting means for detecting an output level of the light-receiving means. A reference position adjusting device that adjusts a reference position of the light shield from an output level change of the light receiving unit by shielding light from the light receiving unit from light from the light receiving unit. The output level of the light receiving means when not shielded by movement is detected by the level detecting means to be a non-light-shielding level, and light from the light emitting means is partially transmitted to the light receiving means by movement of the light shielding body. So as to shield
The position of the light shield when the output level is at a predetermined ratio with respect to the non-light shield level is set as a reference position.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reference position adjusting device,
The present invention relates to an optical device and an optical device, and more specifically, to a reference position adjusting device, an optical device, and an optical device that can always accurately adjust the reference position of a light shield or an optical component.

[0002]

2. Description of the Related Art FIG. 5 shows a shield 1 and a photosensor P fixed to an object (not shown) which can reciprocate in a predetermined direction a. On the upper wall portion of the package 2 having a U-shaped cross section of the photo sensor P, a light-emitting body 3a (for example, LED ... Light Emitti)
ng Diode) is attached, and the light receiving body 3b (for example, a photodiode) is attached to the lower wall surface facing this. If the shield 1 is to the left of the light emitter 3a and the light receiver 3b in FIG. 5A, the light from the light emitter 3a is projected onto the light receiver 3b without being shielded at all. That is, it is the position of in FIG.

When the tip of the shield 1 is on the line connecting the center of the light emitter 3a and the center of the light receiver 3b, the light from the light emitter 3a is half shielded from the light receiver 3b. This is the position of in FIG. Next, when the tip of the shield 1 moves further to the right in FIG. 5A than the light emitter 3a and the light receiver 3b, the light from the light emitter 3a is completely shielded from the light receiver 3b. This is the position of in FIG.

As shown in FIG. 7, the output (light sensor output) of the photoreceptor 3b is SL3 at the position and SL2 at the position. It is 0 at the position. Therefore,
It can be seen that if the reference position of the object, that is, the shield 1 is set, it may be set when the output of the light receiving body 3b becomes SL2.

However, due to disturbance, for example, the light-emitting body 3
As shown in FIG. 8, the output characteristic changes from b to c due to a large temperature change of a or the light receiving body 3b (or a surrounding temperature change).
, Or c to b. As a result, even with the same level SL2, the tip of the shield 1 is certainly located at the half-shielded position with respect to the characteristic c, but deviated from the characteristic b by Δl (ell) at the output SL _2. Position. That is, the position is not exactly half-shielded. With this, the reference position of the object cannot always be accurately determined. In particular, in the case of an optical device such as an optical device, when a reference position of one optical component is accurately determined in relation to another component, a great accuracy is required, which may be a fatal defect.

Japanese Unexamined Patent Application Publication No. 10-312575 discloses a means composed of a shield plate and an aspherical concave lens as aberration correction means. The shield plate has a numerical aperture NA = 0. 0 suitable for reading information from a CD with a light beam having a wavelength of 785 nm.
A circular transparent portion corresponding to 45 is provided. However, this part is fixed and not movable.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and a reference position adjusting device capable of always accurately determining a reference position of a light shield or an optical component that can reciprocate in a predetermined direction. An object of the present invention is to provide an optical device and an optical device.

[0008]

The above-mentioned problems are provided with a light emitting means, a light receiving means facing the light emitting means, and a level detecting means for detecting the output level of the light receiving means, and are capable of reciprocating in a predetermined direction. In the reference position adjusting device, which adjusts the reference position of the light shield from the change in the output level of the light receiving means by blocking the light from the light emitting means to the light receiving means by moving the light shield, The output level of the light receiving means when the light from the light emitting means is not shielded by the movement of the light shield is detected by the level detecting means to be a non-light shielding level, and the light from the light emitting means is moved by the movement of the light shield. Is partially shielded from the light receiving means, and the position of the light shield when the output level reaches a predetermined ratio with respect to the non-light shield level is set as a reference position. Reference position adjusting apparatus characterized by the the so is solved by.

Alternatively, the light emission means, the light reception means facing the light emission means, and the level detection means for detecting the output level of the light reception means are provided, and the light emission is caused by the movement of the optical component reciprocable in a predetermined direction. In the optical device having a reference position adjusting device adapted to adjust the reference position of the optical component from the change in the output level of the light receiving means by blocking the light from the means to the light receiving means, the light from the light emitting means Is detected by the level detecting means to detect the output level of the light receiving means when the light is not shielded by the movement of the optical parts, and the light is emitted from the light emitting means by the movement of the optical parts. The position of the optical component when the output level reaches a predetermined ratio with respect to the non-shielding level is set as a reference position by partially shielding the means. Optical device is characterized in that so as to be solved by the.

Alternatively, in the optical device including at least a laser light source, spherical aberration correction means, an objective lens for condensing light emitted from the laser light source, and a light receiving detector for detecting return light, the spherical aberration The correcting means includes a reference position adjusting device, and the reference position adjusting device includes a light emitting means, a light receiving means facing the light emitting means, and a level detecting means for detecting the light receiving level of the light receiving means, and the predetermined direction. The reference position of the spherical aberration correcting means is adjusted from the change in the output level of the light receiving means by blocking the light from the light emitting means to the light receiving means by the movement of the spherical aberration correcting means reciprocally movable. And the output level of the light receiving means when the light from the light emitting means is not blocked by the movement of the spherical aberration correcting means by the level detecting means. The light output from the light emitting means is partially shielded by the light receiving means by the movement of the spherical aberration correcting means, and the output level is set to a predetermined ratio with respect to the non-light shielding level. The optical device is characterized in that the position of the spherical aberration correcting means when it becomes a reference position is set as a reference position.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an optical device according to an embodiment of the present invention will be described with reference to FIGS. Figure 1
1 shows an optical device which is a main part thereof, that is, a spherical aberration corrector 10 according to the present embodiment, it is composed of a holder 11 for holding a convex lens 12 and a holder 13 for holding a concave lens 14. The holder 11 of the convex lens 12 is fixed to the OP base of the present apparatus although not shown. The holder 13 of the concave lens 14 is fixed to a holder driving rack 15, which fixes a light-shielding body 16 that can reciprocate in a predetermined direction according to the present invention, and the tip portion thereof has a rotating shaft of a stepping motor 17. Is engaged with the lead screw 19.

The holder driving rack 15 reciprocates in the direction indicated by the arrow d due to the rotation of the stepping motor 17 and the engagement with the lead screw 19. The holder driving rack 15 is accurately moved in the direction d. Therefore, the guide shaft 20 is provided. The light shield 16 is the photo sensor 3
A light-shielding main body 16a that can freely move in and out of 0 is formed, and the tip portion thereof is located inside the U-shaped package 31 of the photosensor 36. Both ends of the lead screw 19 are rotatably supported by the angle 18. The angle 18 is fixed to an OP base (not shown).

On one wall of the package 31, the luminous body 3 is provided.
3 is attached, and the light receiving body 34 is attached to the other wall. Further, on the lower surface of the package 31, there is integrally formed a pin portion 32 (a screw is formed on the lower end portion) which is inserted into a long hole formed in an OP base (not shown). It is configured to be fixed to the base. The photodetector 34 is connected to a level detector Q that detects its output.

FIG. 2 is a block diagram of the entire optical device including the spherical aberration corrector 10 of FIG. 1. In FIG. 2, the laser beam emitted from the laser light source 41 is collimated by a collimator 42, This is guided to the beam splitter 43, horizontally shifts as it is as shown in the figure, and then passes through an expander lens 44 as a main part of the spherical aberration corrector 10 according to the present invention and passes through a λ / 4 plate 45.
Finally, it is focused by the objective lens 46 and focused on the recording surface of the disk 47.

The expander lens 44 as the spherical aberration corrector 10 according to the embodiment of the present invention comprises a convex lens 12 and a concave lens 14 as shown in FIG. 1, and the concave lens 14 is formed by a stepping motor 17 shown in FIG. It can be moved to the left and right in FIG.

The light reflected from the disk 47 is bent 90 degrees by the objective lens 46, the λ / 4 plate 45, the expander lens 44, and then the beam splitter 43, and the condensing lens 48.
To the light receiving detector 49. The light-receiving detector 49 has a known structure, and its output is guided to the control device 50 to perform conventionally known various calculations and various controls. In the embodiment of the present invention, particularly spherical aberration correction calculation is performed. A motor is provided to move the concave lens 14 for the necessary spherical aberration correction by providing a circuit, and a pulsed drive output for this purpose is provided. That is, it is moved by a predetermined amount depending on the number of pulses.

The configuration of the embodiment of the present invention is as described above. Next, this function, particularly the adjusting method of the photosensor 30 will be described.

As shown in FIG. 4A, in the manufacturing factory, a reference disk is prepared for pickup adjustment,
On the other hand, the optical device shown in FIG. 2 irradiates the information surface of the disc with a laser beam to guide the reflected light passing through the objective lens 46 to the light receiving detector 49. The stepping motor 17 is rotated to correct spherical aberration by a predetermined calculation in the control device 50. At this time, the adjustment may be performed while observing the waveform of the signal with a time interval analyzer (TIA). That is, the concave lens 14 of the expander lens 44 moves to the right or left in FIG. 2, and stops the stepping motor 17 when the optical adjustment is performed and the spherical aberration is corrected. The stepping motor 17 has a lock mechanism so that the concave lens 14 does not move at all during the following adjustment of the photosensor 30.

The photo sensor 30 (having the characteristic e in FIG. 3) is provided on an OP base (not shown) so that its position can be adjusted. At the tip of the shield body 16a passing through the package 31, the inside of the package 31 is provided. The light-emitting body 34 and the light-receiving body 33 of FIG. At this position, the light from the light emitter 34 is reflected by the light receiver 33.
Is completely shielded against and is therefore in the''position shown in FIG. That is, the optical sensor output is zero.

Next, referring to FIG. 1, the shield plate body 16 is relatively moved.
The package 31 is moved so that a is leftward at a position largely separated from the light emitter 34 and the light receiver 33. As a result, all light rays from the light emitter 34 are received by the light receiver 33.
Projected on. Therefore, in FIG. 3, the output level of the photodetector 33 is maximum L ₂ . That is, the position of '.

The package 31 is moved to the left so that the shield body 16a is located relatively to the right in FIG. At this time, although move while observing the output of the photoreceptor 33, the output level L ₂ 3 2
When the output L ₂ ′ becomes one-half, the package 31 is stopped there and the pin 32 is fixed to the OP base by, for example, a screw. This is the photosensor adjustment position in FIG.

Next, a case where a general user uses it will be described. As shown in FIG. 4B, a commercially available disc is set in the optical device and the origin is set, that is, the shield body 16a.
The reference position of is determined, but this is because when the output level of the photodetector 33 deviates from L ₂ 'as described above,
The stepping motor 17 is driven as much as L ₂ 'according to its size. As a result, the origin is set, the control device 50 then calculates the spherical aberration correction, drives the stepping motor 17, and stops when the spherical aberration is corrected. In this way, the calculation of how much to move from the origin is performed. After that, desired disk reading is performed.

According to the present embodiment, the photo sensor 30
3, even if the output characteristics of FIG. 3 change with d, e, f and disturbance, for example, the temperature change of the photoreceptor 34, the maximum outputs L ₁ , L ₂ , and L _{3 at '} are read, and the output of half of the read value is output. Since L ₃ ', L ₂ ', and L ₁ ', which are the reference positions, are set as reference positions when the photoreceptor outputs, it is possible to accurately take the position of' (1 / 2max) as clearly shown in FIG. it can.

In the above description, since the light beam of the light-emitting body 33 is actually projected with a certain spread, it is not linear as shown in the drawing, but rather a slightly concave or convex curve. However, in the above embodiment, if there is considerable directivity, the above setting does not cause a large error. When a laser beam emitting body is used as the light emitting body 33, its luminous flux becomes an elliptical shape, but if this is adjusted to a square shape by a known means, it is almost ideally a straight line between'and '. Can be Therefore, it is possible to more accurately set the origin or set the reference position.

Although the embodiment of the present invention has been described above, the present invention is not limited to this, and various modifications can be made based on the technical idea of the present invention.

For example, in the above embodiments, the optical device is used, but the present invention may be applied to other recording / reproducing devices.

In the above embodiments, the spherical aberration corrector is described as an optical component, but the present invention is not limited to this, and another optical component, for example, any one of the optical components shown in FIG. The present invention may be applied when the relative position needs to be precisely defined.

Although the concave lens 14 of the expander lens is moved in the above embodiments, the convex lens 12 may be moved instead.
The positional relationship between the concave lens 14 and the convex lens 12 may be reversed.

Further, in the above embodiment, the origin or the reference position is set to a position which is 1/2 of the maximum of the sensor output, but it may be replaced with another ratio, for example, 1/3.

[0030]

As described above, according to the reference position adjusting device, the optical device and the optical device of the present invention, the reference position of a certain light shield or optical component can always be accurately determined. The performance of the device using the parts can be significantly improved over the conventional one.

[Brief description of drawings]

FIG. 1 is a perspective view of a spherical aberration corrector according to an embodiment of the present invention.

FIG. 2 is a schematic block diagram of an optical device using the spherical aberration corrector.

FIG. 3 is a chart showing optical sensor output-shielding plate position output characteristics showing the same effect.

FIG. 4 shows a flow of operations for performing spherical aberration correction using the reference position adjusting device according to the embodiment of the present invention, where A is performed on a reference disc in a factory and B is performed on a general disc. It is a flowchart which shows the case.

5A and 5B show a structure of a conventional photosensor, in which A is a longitudinal sectional view and B is a lateral sectional view.

FIG. 6 is a chart showing the same effect.

FIG. 7 is a chart showing the same optical sensor output-shielding plate position and characteristics.

FIG. 8 is a chart showing fluctuation due to disturbance.

[Explanation of symbols]

10 ... Spherical aberration corrector, 16a ... Shading main body, 17
...... Stepping motor, 30 ...... Photo sensor, 31
...... Package, 33 …… Light emitter, 34 …… Receptor

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 2H043 AD03 AD17 AD23                 2H044 AJ06 DC01                 5D117 AA02 CC07 DD10 KK13                 5D119 AA11 AA22 AA36 AA38 BA01                       EB02 EC01 JA09                 5D789 AA11 AA22 AA36 AA38 BA01                       EB02 EC01 JA09

Claims (8)

[Claims] 1. A light emitting means, a light receiving means facing the light emitting means, and a level detecting means for detecting an output level of the light receiving means. In the reference position adjusting device, which adjusts the reference position of the light shield from the change in the output level of the light receiver by shielding the light from the light receiver to the light receiver, The output level of the light receiving means when the light is not shielded by the movement of the light is detected by the level detecting means as a non-light shielding level, and the light from the light emitting means is partially transmitted to the light receiving means by moving the light shielding body. To shield
A reference position adjusting device, wherein a position of the light shield when the output level reaches a predetermined ratio with respect to the non-light shielding level is set as a reference position. 2. A light emitting means, a light receiving means facing the light emitting means, and a level detecting means for detecting an output level of the light receiving means, wherein the light emission is caused by the movement of an optical component reciprocally movable in a predetermined direction. In the optical device having a reference position adjusting device adapted to adjust the reference position of the optical component from the change in the output level of the light receiving means by blocking the light from the means to the light receiving means, the light from the light emitting means Is detected by the level detecting means to detect the output level of the light receiving means when the light is not shielded by the movement of the optical parts, and the light is emitted from the light emitting means by the movement of the optical parts. The position of the optical component when the output level reaches a predetermined ratio with respect to the non-shielding level is set as a reference position by partially shielding the means. An optical device characterized by the above. 3. The optical device according to claim 2, wherein the optical component is spherical aberration correcting means. 4. The spherical aberration correction means includes an expander lens including a concave lens and a convex lens, and a shield means fixed to either one of the concave lens and the convex lens for shielding light from the light emitting means. The optical device according to claim 3, wherein the one is reciprocally movable in a predetermined direction. 5. The optical device according to claim 4, wherein one of the concave lens and the convex lens is driven by a motor. 6. An optical device comprising at least a laser light source, spherical aberration correction means, an objective lens for condensing light emitted from the laser light source, and a light receiving detector for detecting return light, wherein the spherical aberration The correcting means includes a reference position adjusting device, and the reference position adjusting device includes a light emitting means,
The light receiving means facing the light emitting means and the level detecting means for detecting the light receiving level of the light receiving means are provided, and the light from the light emitting means is moved by the movement of the spherical aberration correcting means capable of reciprocating in a predetermined direction. When the reference position of the spherical aberration correcting means is adjusted based on the change in the output level of the light receiving means by blocking the light receiving means, and the light from the light emitting means is not blocked by the movement of the spherical aberration correcting means. The output level of the light receiving means is detected by the level detecting means to make it a non-light-shielding level, and the light from the light emitting means is partially blocked by the light receiving means by the movement of the spherical aberration correcting means. The position of the spherical aberration corrector when the output level becomes a predetermined ratio with respect to the non-shielding level is set as a reference position. Manabu apparatus. 7. The spherical aberration correction means includes an expander lens composed of a concave lens and a convex lens, and a shield means fixed to either one of the concave lens and the convex lens for shielding the light from the light emitting means. The optical device according to claim 6, wherein the one is reciprocally movable in a predetermined direction. 8. The optical device according to claim 7, wherein either one of the concave lens and the convex lens is driven by a motor.