JPS6171430A - Optical information processor - Google Patents

Abstract

PURPOSE:To offer an optical information processor with small size, light weight without requiring light axis alignment by forming a light intensity detecting means onto a substrate formed on an optical wave guide so as to detect the leaked light from the optical wave guide. CONSTITUTION:A leaked light detecting element 13 is provided on an optical wave guide layer 21 on the upper face of the board 12. All the light propagated to the optical wave guide layer 21 is not irradiated by a coupling lens 23, but the light passing through the position of the lens 23 and leaked to a photodetector section 30 exists and the leaked photodetecting element 13 detects the intensity of the leaked light. Since the variation in the intensity of the light propagated in the layer 21 appears as the intensity variance of the leaked light, the light intensity propagated to the optical wave guide layer 21 is detected indirectly by detecting the intensity of the leaked light. The intensity signal detected is fed back to a drive circuit of a semiconductor laser 11 to make the output light of the semiconductor laser 11 stable.

Description

[Detailed Description of the Invention] Background of the Invention (1) Technical Field of the Invention The present invention focuses laser light from a semiconductor laser or the like, irradiates it onto the information recording section of an optical disk, and uses the intensity change of the reflected light to The present invention relates to an optical information processing device, typified by an optical pickup device that reads information from an optical disc.

(2) Description of the Prior Art In recent years, as high-density optical discs and memories have been put into practical use, there are expectations for the development of high-performance, compact and lightweight optical pickup devices.

The main parts of a conventional optical pickup device consist of an optical system and a drive system.The optical system basically focuses a laser beam onto the information recording area of an optical disk using a focusing lens, and collects the reflected light from the optical disk. It has the function of converting light into an electrical signal using a photodiode, and changes in the amount of reflected light due to information recorded on the optical disk are extracted as electrical signals.

The optical system includes an isolator optical system that separates light irradiated onto the optical disc and light reflected from the optical disc, a beam focusing optical system that focuses the light irradiated onto the optical disc into a spot with a diameter of about 11III, and and an error detection optical system for detecting focusing errors and tracking errors. These optical systems are constructed by appropriately combining elements such as a semiconductor laser as a light source, various lenses, prisms, diffraction gratings, mirrors, quarter-wave plates, and photodiodes.

The drive system includes a focusing drive system, a tracking drive system, and a radial feed drive system.

The focusing drive system is a mechanism for maintaining an appropriate distance between the focusing lens and the optical disk surface so that the light beam focused by the focusing lens forms a correct spot on the optical disk surface. The most common type is one in which the adjustment is made by moving the focusing lens in the direction of its tip axis.

The tracking drive system is a mechanism for tracking the laser spot so that it does not deviate from the track of the optical disk. These mechanisms include one that adjusts by moving the focusing lens in a direction perpendicular to the optical axis, one that adjusts by moving the entire optical pickup head in the radial direction of the optical disk,
A device that adjusts the angle of incident light to a focusing lens using a movable mirror (pivoting mirror) is generally used.

The radial feed drive system is a mechanism for feeding the optical pickup head in the radial direction of the optical disk, and generally uses a linear motor for this purpose.

Such conventional optical pickup devices have the following drawbacks.

The optical system is complex and alignment of the optical axis is troublesome, and
The optical axis tends to shift when shooting.

There are many parts, and assembly takes time, resulting in poor productivity.

Since the optical components are expensive, the overall cost is also high.

Since the optical components are large, the optical pickup device is also large, and a mechanism for holding the optical components is also required, which increases the overall weight.

Summary of the Invention (1) Purpose of the Invention An object of the present invention is to provide an optical information processing device that is small and lightweight and does not require optical axis alignment.

(2> Structure, operation, and effect of the invention The optical information processing device according to the present invention includes an optical waveguide formed on a substrate, a light source of a laser beam introduced into the leading waveguide, and a laser beam formed on the optical waveguide that propagates through the optical waveguide. A lens means for emitting light obliquely upward and condensing it two-dimensionally, a means for receiving light reflected from an obliquely upward direction, and a means for detecting the intensity of the light propagating through the leading waveguide. It is characterized by

In this invention, since lenses, prisms, diffraction gratings, mirrors, quarter-wave plates, and the like are not used as optical components, the device can be made smaller and lighter.

In particular, since the laser beam is emitted diagonally upward from the leading waveguide and the reflected light from diagonally upward is received, it is possible to omit the isolator optical system required in the optical system of conventional optical pickup devices. can. For optical axis alignment, it is only necessary to position the light receiving means. leading wave path,
If the lens means and the light receiving means are formed on the same substrate,
There is no need to align the optical axis during assembly.

A semiconductor laser is generally used as a light source for laser light introduced into an optical waveguide on a substrate. Semiconductor lasers are prone to fluctuations in output light due to temperature changes, etc., and when the output light fluctuates, there is a possibility that an optical information processing device may malfunction.

In this invention, since a means and stage for detecting the intensity of light propagating through the optical waveguide is provided, the light intensity detection signal from this detecting means is fed back to the drive circuit of the light source, so that the output light of the light source, especially the semiconductor laser The intensity can be stabilized, and accurate operation of the optical information processing device can be expected.

By forming the light intensity detection means on the substrate on which the leading waveguide is formed and detecting leakage light from the leading waveguide, further integration and miniaturization of the device can be achieved. If the intensity of the light propagating in the leading wavepath changes, the intensity of the leaked light also changes, so it is possible to monitor the intensity of the light propagating in the leading wavepath even through the leaked light.

DESCRIPTION OF THE EMBODIMENTS (1) Outline of the structure of the optical pickup head FIG. 1 shows the structure of the optical pickup head. Base (10
) on which a semiconductor laser (11) and a substrate (12) are arranged and fixed. The semiconductor laser (11) has electrodes (18) (19)' formed on the base (10).
It is driven by a drive current given to.

For example, a 3i crystal is used for the substrate (12), and S! 02 buff? After the layers have been formed, an optical waveguide layer (21) is formed by sputtering a glass such as Corning 7059. Rade light emitted from the semiconductor laser (11) enters and propagates into this leading wave FFA (21).

On the leading wave [(21) is a collimating lens (2
2), coupling lens (23), leakage light detection element (13), leakage light) heavy area groove (15), and light receiving part (
30) are provided in this order. The collimating lens (22) converts the spread laser beam emitted from the semiconductor laser (11) into parallel light.The coupling lens (23) converts the spread laser beam emitted from the semiconductor laser (11) into parallel light. The laser beam is emitted obliquely upward and focused two-dimensionally.The emitted laser beam is focused into a spot (1/
! The point forming the diameter (approximately E diameter) is indicated by P. When reading information recorded on an optical disc, the laser spot P is positioned on the information recording surface of the optical disc.
This optical pickup head (9) is arranged.

The light receiving section (30) is for receiving the reflected light from the information recording surface of the optical disc, and is arranged at a position where it can receive the light reflected diagonally downward from the position of the laser spot P at the upper 1 ri. It's been done.

The light receiving section (30) includes four independent light receiving elements (31) to
It consists of (34). The light receiving elements (31) <32) are arranged adjacent to the center, and these light receiving elements (31)
Other light receiving elements (33) and (34) are provided before and after (32). These light receiving elements (31) to (34)
For example, four independent amorphous silicon layers (a-si
>It is constructed by creating a photovoltaic element. The output signals of the light receiving elements (31) to (34) are guided from the electrodes at both ends to the electrodes (35) by the wiring pattern formed on the optical waveguide layer (21), and then to the base (10) by wire bonding. ) above are respectively guided to 1fffl (36).

Since information recorded on an optical disc appears as a change in the intensity of reflected light, all of these light receiving elements (31) to (
34) or the sum signal of the output signals of the light receiving element (31) and (
The sum signal of 32) becomes the recorded information read signal.

Other materials for photovoltaic elements include Cd and Tc.

CdS or the like can be used, and these may be formed on the optical waveguide layer (21) by vapor deposition, sputtering, or the like to form a photoconductive cell.

In this way, the light receiving part (30) can be formed by accurately setting its position by mask processing such as the CVD method, so there is no need to align the optical axis during assembly, and the simple structure makes production easier. Sexuality also improves.

Not all of the light propagating through the optical waveguide layer (21) is emitted (air coupled) by the coupling lens (23), but instead passes through the position of the lens (23) and reaches the light receiving section. There is also light leaking toward (30).

The leakage light detection element (13) detects the intensity of this leakage light. Fluctuations in the intensity of light propagating through the leading waveguide layer (21) also appear as fluctuations in the intensity of leaked light, so by detecting the intensity of leaked light, the intensity of light propagating through the optical waveguide layer (21) can be indirectly detected. be done. This detected intensity signal is fed back to the drive circuit (as shown) of the semiconductor laser (11), and the output light of the semiconductor laser (11) is stabilized.

As the detection element (13), the above-mentioned a 3 i, C
dTe, CdS, etc. are used and are formed on the leading wave layer (21) by CVD, vapor deposition, sputtering, or the like. The detection signal of the detection element 13) is transmitted to the electrode (11) on the base (10) by wire bonding via the wiring pattern and electrode (16) formed on the optical waveguide layer (21).
It is taken out.

All of the leaked light from the leading wave layer (21) reaches the detection element (1).
3) is not necessarily consumed. Since the light receiving section (30) is formed on the optical waveguide G (21) as described above,
If there is leaked light that passes through the detection element (13), there is a risk that it will be detected. This may cause the optical pickup head to malfunction.

The leakage light blocking groove (15) is provided between the detection element (13) and the light receiving section (30), and is designed to prevent light passing through the position of the detection element (13) and heading towards the light receiving section (30). Its role is to prevent light propagation by reflecting and attenuating the light on the walls of the groove. This groove (15) may be formed directly on the leading wave layer (21) of the base ff1 (12) by ion beam processing, electron beam processing, laser processing, or the like. Groove (15)
The length of is greater than the width of the propagating light. Also groove (15)
The depth may be approximately the thickness of the optical waveguide layer (21).

In FIG. 1, the leading wave [7 (21) is the light receiving section (30
), but the sensing element (13) and the groove (15
), and the optical waveguide layer may not be formed at the location where the light receiving section (30) is provided. In such a case, the leakage light blocking groove (1
5) is better. M=, P on Si substrate (12〉)
The light receiving elements (31) to (34) may be constructed by creating an N junction (photodiode).

Since the optical waveguide layer (21) may be made of a material having a higher refractive index than the substrate, it can be realized using various materials depending on the substrate.

By forming the substrate (12) with a material that has an electro-optic effect such as LiNbO3, it becomes possible to electrically control focusing and tracking as described later. A leading wave layer can be formed by thermal diffusion.Furthermore, a photodetector element and a light receiving section can be formed using a-3i on the upper surface of 1iNb03.

(2) Combined semiconductor laser with a semiconductor laser and an optical waveguide layer (
11) and the leading wave IM (21) on the substrate (12) are butt edges in this embodiment.
Combined using the combination method.

“As shown enlarged in Figure 2, the substrate (12)
The coupling end face of the semiconductor laser (11) is optically polished, and the heights of the active layer (14) and the leading wave layer (21) of the semiconductor laser (11) are adjusted so that the end faces of these two layers (14) and (21) face each other. Then, the semiconductor laser (11) is fixed on the electrode pad (18). Laser light emitted from the semiconductor laser (11) spreads within the optical waveguide layer 21). Semiconductor laser (
11) The optical field distributions in the active layer (14) and the leading wave layer (21) have very similar shapes, so high efficiency coupling is possible and no special coupling means is required. It has the advantage of The base (10) is a semiconductor laser (11)
It also serves as a heat sink.

(3) Collimating lens and coupling
Collimating lenses formed on the lens optical waveguide layer include Fresnel lenses, Bragg grating lenses, Luneburg lenses, and geodesic lenses.

The collimating lens (22
) is a Fresnel lens with an optical waveguide of 1iM (21
) It is formed from a grating or a refractive index distribution in which [1] becomes smaller as it moves away from the optical axis (chirped).

The Bragg grating lens consists of a leading wave layer (21
) consists of a grating or refractive index distribution whose angle with the optical axis increases as the distance from the optical axis increases.

A Luneburg lens is a high refractive index thin film formed on an optical waveguide layer (21) in a circular shape when viewed from above, with a thickness distribution that is thickest at the center and gradually becomes thinner toward the periphery.

The geodesic lens is obtained by forming a curved depression on the surface of the substrate (12) before forming the leading wave 1 (21), and forming the leading wave layer (21) along this depression.

The coupling lens (23) shown in FIG. 1 is a two-dimensional focusing grating coupler, and has a light output function and a two-dimensional focusing ability in one lens. This is composed of arc-shaped gratings (irregularities) whose period (interval) becomes smaller in the direction of travel.

FIG. 3 shows another example of the coupling lens (23). The coupling lens (23) consists of a Fresnel type grating lens (28) (same as the upper jδ Fresnel lens) and a chirped type grating lens (28) (same as the upper jδ Fresnel lens).
It consists of a grating coupler (29). A Fresnel lens has the function of converting light spreading from a single point into parallel light, and the function of focusing parallel light. The grating lens (28) converts parallel light into a leading wave, and the layer (21)
It is used for focusing within. The grating coupler (29) is composed of linear gratings whose period (interval) decreases in the direction of light propagation, and emits the light propagating within the leading wave layer (21) and aligns it in a straight line. It has the function of concentrating light. Optical waveguide layer (21)
Since the light propagating through is focused in the width direction by the grating lens (28), if the focus of the grating lens (28) and the focus of the grating coupler (29) are at the same point P, the optical waveguide layer The light emitted from (21) is condensed to one point at point P.

In addition, in Figures 1 and 3, the grating (
For simplicity, the unevenness is depicted as a line with no width.

(4) Feedback control of leakage light detection element and semiconductor laser The leakage light detection element (13) shown in FIG. 1 is formed to be longer than the width of the leakage light propagation path so as to cross this path. , element (1
The width of '3) may be further increased. FIG. 4 shows another example of the leakage light detection element (13), which is formed in a shape that surrounds the coupling lens (23) when viewed from above.
23) can also be detected.

FIG. 5 shows an aspect of manufacturing the leakage light detection element.

FIG. 5 (△) shows that the cable (13) is simply placed on the optical waveguide layer (21).
) was formed. The field distribution of light propagating through the leading wave layer (21) also extends to the element (13).
) gives a light intensity detection signal of 1.

In FIG. 5 ('B>), a grating in a direction perpendicular to the propagation direction of light is formed on a part of the surface of the leading wave layer (21), and on this grating, the element (1
3) is formed by a method such as vapor deposition. Due to the presence of the grating, leakage light propagating through the optical waveguide layer (21) is radiated in the direction of incidence on the element (13), and a considerable amount of light energy is utilized by the element (13).

In FIG. 5(C), the upper surface of the leading wave layer (21) is made into a rough surface, and the element (13) is formed on this rough surface. Also in this case, most of the leaked light propagating through the optical waveguide layer (21) is disrupted by the rough surface and enters the element (13).

In FIG. 5 (D>), a depression is formed in the leading wave F (21) by etching or the like, and an element (13) is formed in this depression.Most of the leaked light propagating through the leading wave layer (21) enters the element (13) from the inclined surface of the recess, and a portion of the propagating light also enters the element at the bottom of the recess.In Fig. 5(E), the hemispherical recess is polished. It is formed by etc.

In FIG. 5(F), the element (13) is attached to the substrate (12) in contact with the end surface of the waveguide layer (21) (the waveguide layer shown by a solid line) or in the middle (the waveguide layer shown by a chain line). embedded within. For example, forming a hole in the substrate (12),
A device (13) is deposited in this hole. A groove (15) may be used as this hole.

In FIG. 5(G), an element (15) is formed on the end face of the optical waveguide layer (21), which is the wall surface of a hole (16) formed at the end or in the middle of the optical waveguide layer (21). .

In FIG. 5(H), a large depression (16) is formed over the entire depth of the optical waveguide layer (21), and
1) is cut by an inclined surface over its entire depth direction.

An element (13) is formed on this inclined surface.

In FIG. 5 (F), (G), and (H), since the element (13) is formed on the end face of the optical waveguide layer (21), almost all of the leaked light propagating through the leading wave 1 (21>) is input to the cord (13) and used. Therefore, high efficiency and large electromotive force can be obtained. In these figures, the hole or depression (16) and the leakage light blocking groove (15) are shown. May be shared.

FIG. 5(1) shows yet another example.

Here, the hole (16) is deeper than the thickness of the leading wave layer (21).
) or a leakage light blocking groove (15) is formed, and this hole (
16) or 1 (Is) is provided with a photodiode chip (13) as a sensing element. The light emitted from the optical waveguide layer (21) passes through this photodiode (1-
3) is received.

The semiconductor laser (11) may be controlled by known feedback control based on the output signal of the leakage light detection element (13) as described above. In other words, the light reception signal of the element (13) is transmitted at fixed time intervals (digital system t1) or continuously (
Analog control) Compare with the previous value or with a certain reference value,
If it is kept constant, the drive current of the semiconductor laser (11) is kept at the same value. When the received light intensity decreases, the drive current is increased so that the deviation becomes 0, and when the received light intensity increases, the drive current is decreased. Such a control procedure is shown in a flow chart in FIG. Through this feedback control, the semiconductor relay If(
11) can be stabilized.

(5) Leakage light blocking groove Leakage light blocking groove shown in Figures 1 and 3 (15)
is formed in a straight line substantially perpendicular to the light propagation direction. This groove (15) has a simple structure and can be easily produced.

FIG. 7 shows another example of the leakage light blocking groove. The leakage light 'f4 cutoff groove 5) shown in FIG. It is formed in a form further tilted from the direction perpendicular to the light propagation direction. Although this groove (15) is formed in a bent shape with the apex at the position of the optical axis, it may also be formed so as to cross the light propagation path in a straight line and diagonally. Using this type of groove can prevent back talk noise caused by reflected light returning to the semiconductor laser (11).

The groove (15) shown in Figure 7(B)
The wall on the lens side has a corrugated finish. Leakage light is scattered by this wall surface. Other shapes of unevenness may be formed on this wall surface.

(6) Detection of Focusing Error Bits (indentations) representing digital information by length and position are formed along the track on the information recording surface of the optical disc. FIG. 8 shows the positional relationship between the optical disk (81) and the optical pickup head (9) by cutting the optical disk (81) along its circumferential direction.

The laser beam emitted from the coupling lens (23) is transmitted to the information recording surface of the optical disk (81) (bits (in Fig. 8)).
82) and is received by the light receiving section (30). FIG. 9 shows the range in which the light receiving section (30) is irradiated with the reflected light from the optical disk (81).

In FIG. 8, the optical disc (81) and the bit (82) shown by solid lines have an optimal distance between the optical disc (81) and the optical pickup head (9), and the optical disc (81) of the emitted light is This shows how upward focusing is performed correctly. The irradiation area of the reflected light in the light receiving section (30) at this time is indicated by Q.

This irradiation area Q is the central light receiving element (31) (32)
The other light receiving elements (33) (34)
No reflected light is received.

Optical disc (81) when the distance between the optical disc (81) and the pickup head (9) becomes relatively large or small and proper focusing cannot be performed
The position of is shown in dashed lines in FIG. Optical disc (8
1) and the pickup head (9) becomes relatively small (displacement of -Δd), the illuminated region 9A (represented by Ql) of the reflected light is shifted to the light receiving element ( 33
) to the side. Since the light receiving element (33) is connected to the negative side of the differential amplifier (71) and the light receiving element (34) is connected to the positive side, in this case, the output of the differential amplifier (71) has a negative value. This value represents the magnitude of the displacement -Δd.

When the distance between the optical disc (81) and the pickup head (9) becomes relatively large (displacement of +Δd), the reflected light irradiation area (represented by Q2) becomes light-receiving. Move closer to Sakuko (34). The output of the differential amplifier (71) shows a positive value, and this value does not represent the displacement m+Δd.

In this way, it is possible to determine whether the focusing of the light beam emitted from the pickup head (9) is appropriate, and if a focusing error has occurred, the direction and magnitude of the error are determined by the output of the differential amplifier (71). Detected from. If there is no focusing error, a differential amplifier (
The output of 71) is zero.

(7) Tracking error detection Figure 10 shows the bits (
82) and the light-receiving elements (31) and (32) of the light-receiving section (30) are shown arranged on the same plane, so to speak.
) (32).

The differential amplifier (72) is illustrated for the purpose of clarifying the electrical connection relationship with the light receiving elements (31) and (32). Figure 10 (A) shows that the center of the laser beam spot P is located exactly on the center of the track (bit (82)) in the width direction. Figure 10 (B) (
C) shows that the spot P is slightly shifted to the left and right of the track (bit (82)), causing a tracking error. In either case, it is assumed that proper focusing is achieved.

The laser spot P hits the information recording surface of the optical disk (81), and the intensity of the reflected light is modulated by the presence of the bit (82). This is because the spot size is slightly larger than the width of the bit (82).
) and light reflected from parts other than the bit (82), and the depth of the bit (82) is 1/4λ.
(λ is the wavelength of the laser beam), a phase difference of π occurs between the two types of reflected light, which cancel each other out and reduce the light intensity. There is an explanation that light scattering occurs at the edges of 82), which reduces the intensity of the reflected light received. In any case, due to the presence of the bit (82), the light receiving section (
The intensity of the light received at 30) becomes smaller.

The light receiving elements (31) and (32) are divided into left and right parts with the optical axis as a border. Center of laser spot P and bit (8
2), the amounts of light received by the light receiving elements (31) and (32) are equal, and the output of the differential amplifier (72) is zero.

As shown in FIG. 10(B), when the laser spot P shifts to the left side of the bit (82), the light receiving element (31
), the amount of light received by the differential amplifier (72
) produces a positive output. Conversely, as shown in FIG. 10(C), when the laser spot P shifts to the right side of the pit (82), a negative output is generated in the differential amplifier (72).

In this way, the output of the differential amplifier (72) determines whether the beam spot P is accurately along the track of the optical disk (81), whether a tracking error has occurred, and whether it has shifted to the left or right. An error is detected.

(8) Focusing and tracking drive mechanism FIGS. 11 to 13 show a focusing drive mechanism and a tracking drive mechanism.

A support member (1oi) is erected at one end of the support plate (100). Both lower ends of this support member (1oi) are notched (symbol (102)).

A movable member (103) is located above the other end of the support plate (100).
is located. One end of the four leaf springs (121) (122) that can be elastically bent in the vertical direction is attached to the support member (1
01) is fixed to both sides of the upper end and the lower notch (102), and the other end is fixed to both sides of the upper end and lower end of the movable member (103), respectively. Therefore, the movable member (103) is moved by these leaf springs (121) (122
), the support member (10
1) is supported.

The stage (110) with the optical pickup head (9) has an upper rectangular frame (112) and two legs (114) extending downward from both ends of the rectangular frame (112).
(115) and a groove extending downward from the center of the rectangular frame (112) 1=central leg (113). An optical pickup head (9) is mounted and fixed on a rectangular frame (112). One end of four leaf springs (131) that can be elastically bent in the lateral direction is on both sides of the movable member (103),
It is fixed at the bottom, and the other end is attached to the central leg (1io) of the stage (1io).
113) on both sides and at the bottom. stage(
110) is supported via these leaf springs (131) so that it can move laterally (corresponding to the left-right direction in FIG. 10). Therefore, the stage (110) is
It can be moved vertically (focusing) and horizontally (tracking).

Support plate (100), support member (101), movable part i
4 (103) and the stage (1io) are made of non-magnetic material, such as plastic.

Yokes (104) (105) are fixed to the inner surfaces of the support member (101) and the movable member' (103). The yoke (104) includes a vertical portion (104a) fixed to the support member (101), another vertical portion (104b) located at a distance from this, and both of these portions (104a) (104b). and a horizontal section joining them at their lower ends.

The yoke (105) also has exactly the same shape as the yoke (104), with two vertical parts (10
5a) Tail with (105b).

The vertical part of these yokes (1o4) (1os) (
104a ) (1'05a) are each fixed with a permanent magnet (106) whose inner surface is, for example, an S pole. And yoke (104) (1
05) the other vertical part (ioab) (iosb)
A stage (,110) is placed between the permanent magnet (1oe) and the permanent magnet (1oe).
The legs (114) and (115) of the two are inserted into each other without touching them.

A focusing drive coil (123) is wound horizontally around both legs (114) (115>) of the stage (110).
(115) is wound with a tracking drive coil (133) having a portion facing the permanent magnet (106) in the vertical direction with J5.
' The focusing mechanism is best shown in FIG. The magnetic flux H generated from the permanent magnet (106) is connected to the yoke (104)' (105
) towards the vertical parts (104b) (105b), respectively. When a driving current is applied to the coil (123) arranged horizontally across this magnetic field, for example in the direction toward the plane of the paper in FIG. 12, an upward force F[ is generated. This force Ff moves the stage (11,0) upward. The amount of movement of the stage (110) is equal to the amount of movement of the stage (110).
3) It can be adjusted by the magnitude of the current applied. Therefore, focusing control can be performed by switching the direction of this drive current according to the output signal of the differential amplifier (71) mentioned above, adjusting the magnitude of the current, or turning the current on and off. can.

The tracking drive arrangement is best illustrated in FIG. When a driving current is applied to the lζ portion of the coil (133), which is disposed vertically across the magnetic field H, for example, in the direction toward the plane of the paper in FIG. 13 (downward in FIG. 11), in FIG. An upward force (lateral force in FIG. 11) Ft is generated, and the stage (110) moves in the same direction. Tracking control can be performed by turning on or off the current flowing through the coil (133) according to the output signal of the differential amplifier (72) mentioned above, and by adjusting the direction of the current and, if necessary, its magnitude. can.

Focusing and tracking can also be controlled using electro-optic effects.

For example, the optical waveguide (21) (and the substrate (12)
) is a material with electro-optic effect (for example, LiNb03
) or a grating lens (28
) (41)-(43) and Grating Cabra (
29) Form a thin film of a material with an electro-optic effect (for example, ZnO or A/N) at the locations of (51) to (53) (see Figures 3 and 14), and then coat both sides of these lenses and coverrs. Provide electrodes. By changing the voltage applied to the electrodes, the focal lengths of these lenses and foggers can be adjusted, thereby performing focusing control and tracking control. Instead of the grating lens, an electrode array consisting of a large number of electrodes is formed on the leading wave layer, and a refractive index distribution is formed in the optical waveguide by applying a stepped voltage to this electrode array. Focusing and tracking control can also be performed using such a gradient index lens. Tracking can also be controlled by deflecting the light beam propagating through the guide waveguide (21) using the electro-optic effect. Deflection of the light beam can be achieved, for example, by using interaction between light and SAW (surface acoustic waves).

(9) Other embodiments FIG. 14 shows a 3-beam optical pickup head (
90). In this figure, the same parts as shown in FIG. 1 are given the same reference numerals.

Here, the coupling lens (23) separates the laser light that has propagated through the optical waveguide layer (21) into three parts diagonally upward and emits them, and sends these light beams to three different points. Dimensional focusing. The coupling lens (23) consists of three Fresnel type grating lenses (Fresnel lenses) arranged in a line across the propagation path of the laser light converted into parallel light by the collimating lens (22〉). 41)～
(43) and these grating lenses (41〉
~(43)
) gratings/cobras (51) to (53).

Each of these grating cabras (51) (52
) (53) respectively point to points Pi, P2, and P.
Focus on 3. The diameter of these laser spots P1 to P3 is about 1 ttm, and the interval is about 20III7. Laser spot 1-P1 in the center is for reading information on the optical disc and detecting focusing errors, and laser spots P2 and P3 on both sides are for tracking.
This is for error detection. These spots P1 to P3 are focused on the information recording surface of the optical disc on the same plane, and are arranged substantially in a straight line.

The light receiving section (30) is arranged at a position where it can receive light reflected diagonally downward from the positions of the laser spots P1 to P3. The light receiving section (30) consists of five independent light receiving elements (91) to (95). Central photodetector (91
) is for reading information, and the anti-ql from spot P1
Receive light.

The light receiving elements (92) and (93) located before and after it are used for focusing error detection. Light receiving elements (94) and (95) on both sides of the light receiving element (91) are for tracking error detection, and receive reflected light from spots P2 and P3, respectively. The output signals of the light receiving elements (92) (93) are input to the above-mentioned focusing error detection differential amplifier (71), and the output signals of the light receiving elements (94) (95
) output from the tracking error detection differential amplifier (7
2) Enter.

Information recorded on an optical disc appears as changes in the intensity of reflected light. The reflected light of spot P1 is reflected by the light receiving element (31)
The output signal becomes a reading signal for recorded information. The sum signal of the light receiving elements (31) to (33>) may be used as the read signal.

In this embodiment as well, the light receiving elements (91) to (95) are formed on or within the substrate (12) using a-8i, CdTe, CdS, etc. or by PN junction. Furthermore, a leakage light detection element (13) and a leakage light blocking groove (15) are formed between the coupling lens (23) and the light receiving section (30).

[Brief explanation of drawings]

FIG. 1 is a perspective view of an optical pickup head. FIG. 2 is a perspective view showing an optical coupling portion between a semiconductor laser and a light wave layer. FIG. 3 is a perspective view showing another embodiment of the coupling lens. FIG. 4 is a plan view showing another example of the leakage light detection element. FIG. 5 is a cross-sectional view showing various examples of leakage light detection elements. FIG. 6 is a flow chart showing an example of semiconductor laser control based on the intensity detection signal. FIG. 7 is a perspective view showing another example of the leakage light blocking groove. FIG. 8 is a sectional view showing the positional relationship between the optical disk and the optical pickup head. FIG. 9 is a diagram showing the principle of detecting a focusing error that appears on the light receiving section. FIG. 10 is a diagram showing the principle of tracking error detection. Figures 11 to 13 show the focusing and tracking drive mechanism, with Figure 11 being a perspective view and Figure 1 being a perspective view;
2 is a sectional view taken along the line X--X in FIG. 11, and FIG. 13 is a plan view with the optical pickup head removed. , FIG. 14 is a perspective view showing another example of the optical pickup head. (9) (90)... Optical pickup head, (11
)...Semiconductor laser, (12)...Substrate, (13)
... leakage light detection element, (21) ... optical waveguide layer, (2
2)...Collimating lens, (23)...
Coupling lens, (30)... Light receiving section, (31
) to (34) (91) to (95)...light receiving elements. 4 people other than above 5 BBH (A) (B) (C) Fig. 5 (D) (E) (F) Fig. 5 (G) (H) (I) Fig. 6 1

Claims (2)

[Claims] (1) An optical waveguide formed on a substrate, a light source for laser light introduced into the optical waveguide, and a light source contracted on the optical waveguide to emit the light propagating through the optical waveguide obliquely upward and focus it two-dimensionally. An optical information processing device comprising: a lens means; a means for receiving light reflected obliquely from above; and a means for detecting the intensity of light propagating through an optical waveguide. (2) The light intensity detection means is formed on the substrate and detects leakage light from the optical waveguide.
The optical information processing device according to item 1).