JP3508749B2 - Integrated optical member and optical pickup device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an integrated optical member used for recording and reproduction of an optical disc, an optical pickup device using the integrated optical member, and an optical disc device using the optical pickup device.

[0002]

2. Description of the Related Art Conventional optical pickups have been devised so that many types of beam splitters are frequently used to separate the emission light source side from the detection optical system. However,
As a result of increasing market demand for miniaturization of optical pickups, attempts have been made to provide the light source and the detection optical system as an optical unit housed in the same package.

To realize this optical unit, an optical member having a diffraction grating is used. A detailed technical disclosure of this optical member is made in JP-A-10-154344. As a result of the realization of the optical member, the size of the optical pickup has been drastically reduced, and a small-sized optical disk device equipped with the small-sized optical pickup has become popular in the market.

[0004]

However, the progress of miniaturization and the widespread use of optical disk devices include the following new problems. For example, the light emission source, the detection element, and the optical member are naturally close to each other due to miniaturization. In addition, due to long-term use and expansion of recording applications, the light output of the light emitting light source increases and the operating temperature also rises. Further, as seen in the popularization of notebook PCs, the environmental temperature in which they are housed or used in smaller casings is further expanding.

Thus, when the operating temperature range is expanded,
The influence of the coefficient of thermal expansion of each component forming the optical unit will be exposed. For example, if the size or position of the optical member on which the diffraction grating is formed is affected, the causes of error and offset in servo control increase.

The present invention has been made in order to solve such a problem, and a signal detecting operation in which the fluctuation of the operating temperature does not affect the detection optical system and is hardly affected by the crosstalk. It is an object of the present invention to provide an integrated optical member capable of realizing the above, an optical pickup device using the integrated optical member, and an optical disc device using the focus error detection method and the tracking error detection method in combination with the optical pickup device. And

[0007]

The present invention has been made to solve the above problems, and guides the luminous flux of a light emitting element to an optical disc and separates a necessary luminous flux from the reflected light from the optical disc. An integrated optical member, wherein the integrated optical member has tracking control from the reflected light.
A diffraction grating that extracts the luminous flux necessary for control and focus control
And the diffraction grating is parallel to the radial direction of the optical disc.
The center area divided into three by the dividing line of the book and the optical disk tongue
A first bow-shaped region and a second bow separated in the genial direction
The central region is divided into
With a dividing line parallel to the first direction and further into the first substantially D-shaped region
It is divided into a second substantially D-shaped region, and the first substantially D-shaped region
The first bow on the side of the tangential direction of the linear region
A first region is formed in each of the shape region and the second arc region.
A separation grating and a second separation grating, further comprising the second
The first portion on the side of the tangential direction of the D-shaped region
Within the second arcuate region and the second arcuate region, respectively.
Characterized by having a third separating grid and a fourth separating grid
Integrated optical member and an optical pickup using this integrated optical member.
CUP device and this optical pickup device
An optical disk device is provided.

According to the present invention, the above-described structure makes it possible to realize a signal detection operation in which the detection optical system is not affected by fluctuations in operating temperature, and a signal detection operation that is less susceptible to crosstalk is realized. and an optical pickup device using the integrated optical member, and it is possible to provide an optical disk equipment using the optical pickup device.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Claims 1 to 3 of the present invention
The described invention guides the luminous flux of the light emitting element to the optical disc.
Along with the reflected light from the optical disc,
An integrated optical member for separating, wherein the integrated optical member is a front
Tracking control and focus control from the reflected light
A diffraction grating for extracting a light beam necessary for
Is divided into three by two dividing lines parallel to the radial direction of the optical disc
In the center area and the tangential direction of the optical disc
Divided into separate first and second arcuate regions,
The central area is divided in parallel with the tangential direction.
The first substantially D-shaped region and the second substantially D-shaped region in a line
And the tang of the first substantially D-shaped region.
In the first arcuate region laterally in the axial direction and in the first
Within the two arcuate regions are a first separating grid and a second separating grid, respectively.
The grid of the second substantially D-shaped region.
Inside and in front of the first arcuate region laterally
In the second arcuate region, there are respectively a third separating grid and a fourth separating grid.
Is an integrated optical member.

According to the present invention, it is possible to provide an integrated optical member in which the detection optical system is not affected by fluctuations in the operating temperature with the above-described configuration, and a signal detection operation that is less susceptible to crosstalk is performed. It is possible to provide an integrated optical member that can be realized, an optical pickup device, and an optical disk device using the same.

[0011]

[0012]

[0013]

[0014]

[0015]

[0016]

Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 1 is a perspective view showing the entire optical pickup. In FIG. 1, the whole is generically called an optical pickup 1 and has the following main components. The composite element 2 emits a light beam 3. The light beam 3 is bent by the mirror 4 and is condensed by the objective lens 5 to be focused on the information recording layer of the optical disc 6. The light reflected from the information recording layer follows the reverse order and is detected by the composite element 2.

On the other hand, the information recording layer of the optical disk 6 is formed with information tracks in a concentric shape (more strictly, a spiral shape). Therefore, the light beam 3 emitted from the composite element 2 is arranged in the tangential (tangential line of the track) direction of the optical disk 6. The actuator 7 supports the objective lens 5 so that it can be displaced minutely. Optical disc 6
In order to focus the light beam 3 on the information recording layer of (focusing) and in the minute track direction (tracking)
This is because The composite element 2, the mirror 4, the objective lens 5, and the actuator 7 described above are mounted on the carriage 8. Therefore, movement exceeding the tracking range is handled by moving the entire carriage 8 in the radial direction of the optical disc 6.

Next, the composite element 2 will be described. FIG. 2 is a perspective view showing the entire composite element. In FIG. 2, the composite element 2 has a configuration including a light source 10, an integrated optical member 20, a light receiver 60, and a coupling member 80. These components will be described in order.

First, the light source 10 comprises a general-purpose semiconductor laser 11 fixed to a base member 12. Since an extremely general-purpose semiconductor laser 11 can be used, the most expensive essential parts can be procured at the lowest cost, and the inexpensive optical pickup device can be provided.

Although not described in detail, the general-purpose semiconductor laser 11 naturally contains the laser element 13 therein and has a virtual light emitting point 19 used for geometrical optical simulation. Light emitting point 1 of laser element 13
The laser light emitted from 9 is emitted from the emission port 16 of the general-purpose semiconductor laser 11. Reference numeral 18 is a lead of the general-purpose semiconductor laser 11, and reference numeral 65 is a flexible cable for connecting to the light receiver 60.

Next, the entire integrated optical member 20, which is the optical member which is the subject of the present invention, will be described. FIG. 3 is an exploded perspective view of the integrated optical member 20. In FIG. 3, the integrated optical member 20 is composed of first to fourth light guide members. As the material of each light guide member, a highly transparent resin material or optical glass is used.

The first light guide member 21 is formed in a parallel plate shape. The first light guide member 21 has a first surface on the side facing the exit 16.
The diffraction grating 22 is formed. This is because the diffracted 0th order light and ± 1st order light are used to generate a main beam and a sub beam (hereinafter collectively referred to as three beams) used for tracking control.
At this time, the pitch of the first diffraction grating 22 and the depth of the grating are
The optimum value is set according to the wavelength of the light beam and the light power of each of the three beams. A light absorbing film 23 prevents unnecessary light such as irregular reflection and stray light from entering the integrated optical member 20.

The second light guide member 25 is formed in a substantially triangular prism shape having a cross section of a substantially right triangle. Slope 2 of a substantially right triangle
A second diffraction grating 27 (outgoing path light extraction means) is formed in a required area of the optical disc 6. The formation process of the second diffraction grating 27 is the same as that of the first diffraction grating 22 described above. Since the light beam that has entered the second light guide member 25 from the first light guide member 21 is diffused light, it is reflected by the second diffraction grating 27 and is focused on the light power detection means 66 (see FIG. 5 described later). This is because it is converted into convergent light. Furthermore, the setting conditions for the grating pitch and the grating depth of the second diffraction grating 27 are the same as those for the first diffraction grating 22 described above. In addition, especially the second diffraction grating 27
Is set so that the + 1st order light becomes the main component of the reflected diffracted light. A large amount of light is converged by the optical power detection means 66,
This is because the optical power to be detected is increased and the detection of the optical power is accurate.

Further, the slope 26 is coated with a round-trip separation film 28 on the entire surface including the second diffraction grating 27. The round-trip path separation film 28 transmits almost 100% of the light beam (outward path) incident from the first light guide member 21, and conversely reflects the light beam from the optical disk 6 and returns to the second light guide member 25 ( It has the function of reflecting almost 100% of the return path.

A side surface 31 which is the other surface of the second light guide member 25.
The side surface reflection film 32 is formed in a predetermined area. This is because the diffracted light reflected by the second diffraction grating 27 is reflected again to form an image on the optical power detection means 66. In the process of forming the integrated optical member 20, the entire side surface 31 including the side surface reflection film 32 is coated with the light absorption film. This is for absorbing unnecessary internal reflection, preventing stray light from entering, and protecting the reflective film coating from the influence of corrosion due to the atmosphere.

The third light guide member 35 is formed in a substantially trapezoidal column shape having a substantially trapezoidal cross section. Each surface is the first slope 36
And a second inclined surface 37, a transmission surface 38, and an emission surface 39.
The first slope 36 and the second slope 37 are parallel planes facing each other, and a third diffraction grating 40 is formed in a predetermined region of the first slope 36. The conditions for forming the third diffraction grating 40 and setting conditions for the grating pitch and the grating depth are the same as those for the first diffraction grating 22 described above.

The third light guide member 35 is the second light guide member 2 described above.
When the light beam is bonded to No. 5, the return light reflected by the round-trip separation film 28 is incident on the third diffraction grating 40. Further, the third diffraction grating 40 makes the reflected diffraction light of the + 1st-order light and becomes the second light guide member 25.
However, it is reflected by the auxiliary reflection film 30 of the slope 26, which will be described later, and is emitted from the emission surface 39 to detect the optical power detection means 66.
Head to. At this time, the slope 26 of the second light guide member 25 corresponding to the area where the reflected diffracted light is reflected by the round-trip separation film 28.
It is effective to form the auxiliary reflection film 30 (that is, between the corresponding region of the slope 26 and the round trip separation film 28). In this way, the reflection ability of the round-trip path separation film 28 with respect to the reflected diffracted light can be improved, and the level fluctuation of the signal detection of the optical power detection means 66 can be suppressed.

The fourth light guide member 45 is formed in a substantially triangular prism shape having a cross section of a right triangle. Each surface is an inclined surface 46, a first surface 47 and a second surface 48. The first surface 47 and the second surface 48 intersect at a right angle and serve as a reference surface of the integrated optical member 20. A light absorption film is formed on the entire surface of the slope 46.

FIG. 4 is an overall perspective view of the light receiver 60. The OE element 63 is housed in the package 61 having the entrance 62. The signal terminal of the OE element 63 is connected to the lead terminal 64 and guided to the outside of the package 61. Furthermore, connect a flexible cable 65 to the lead terminal 64,
Used for inspection and mounting.

FIG. 5 is a pattern diagram of the OE element 63 viewed from the entrance 62. In FIG. 5, reference numeral 66 is an OE element pattern corresponding to the optical power detecting means. Further, 67 is a pattern of OE elements corresponding to the light receiving means, and is composed of 10 OE element patterns in total. In addition, the area indicated by the dot pattern on the OE element pattern is the third diffraction grating 40.
Represents the state in which diffracted light is incident.

Each of the light-receiving means 67 has light-receiving means 67E, 67C, 67G in order in the optical tangential direction as an optical pickup, and a light-receiving means 67B at the center.
67A, subsequently eight OE element patterns of the light receiving means 67F, 67D, 67H are formed, and two OE element patterns of the light receiving means 67a, 67b are formed by shifting in the radial direction of the central portion. In the four OE element patterns in the central part, the disc reflected light of the main beam is reflected by the grating A41 and the grating B4.
It is diffracted by 2 and enters. The four OE element patterns in the central portion are named in reverse order, and signal processing or electrical wiring described later is performed. The disk reflected light of the sub-beams is diffracted by the grating C43 and the grating D44 and enters the light receiving means 67E, 67C and 67G. Similarly, the light receiving means 67F, 67D, 67
In H, the disk reflected light of another sub-beam is diffracted by the grating C43 and the grating D44 and enters.

The optical power detecting means 66 has a reproducing / reflecting light reflected by the side surface reflection film 32 provided on the second light guide member 25.
The outward light in an area that does not contribute to recording forms an image. Light receiving means 6
On + 1st order, the + first-order reflected diffracted light reflected by the third diffraction grating 40 of the above-mentioned return light is imaged. These OE elements 6
3 generates a detection current according to the amount of received light, and it is taken out as an electric signal with an amplifier (not shown) connected in the subsequent stage.

The relationship between the third diffraction grating 40 and the ten OE element patterns of the light receiving means 67 (A to H, a, b) will be described with reference to FIG. The third diffraction grating 40 is provided with four types of grating regions. First, the third diffraction grating 40 is divided into three by two dividing lines that are parallel to the radial (radial) direction (X axis) of the optical disc 6, and is divided into an arched shape in the tangential (track tangent: Y axis) direction. One of the separated areas
One is a grid A41 and the other one is a grid B42.
The area of the lattice A41 is equal to the area of the lattice B42,
The area of the entire area of the diffraction grating 40 is approximately ¼ (thus, the total area of the grating A41 and the area of the grating B42 is approximately ½ of the entire area of the third diffraction grating 40).

The area where the reflected diffracted light of the grating A41 forms an image is the light receiving means 67A provided in the central portion of the light receiving means 67.
And an image is formed on the light receiving means 67B. Further, the area where the reflected and diffracted light of the grating B42 is imaged is imaged on the light receiving means 67a and the light receiving means 67b provided at the lower center of the light receiving means 67. That is, it becomes the main beam for focus detection. As shown in FIG. 5, the light-receiving means 67A and the light-receiving means 67B in the central portion are the light-receiving means 67a and the light-receiving means 6 in the lower center.
7b is the reverse order. Further, in the figure, light receiving means 67A, B,
The blank areas provided on the left and right of a and b are the first diffraction grating 22.
The sub-beam generated in (2) becomes an area where an image is formed by the grating A41 and the grating B42. That is, the three beams generated by the first diffraction grating 22 are reflected by the disk surface and return light 3
Only the diffracted light of the main beam out of the diffracted return light 3 beams which has become a beam and is incident on the third diffraction grating 40 is received by the light receiving means 6.
7A, B, a, and b are imaged.

Now, when the OE-converted detected current is represented by the symbol I, IA, IB, and I are detected by the respective light receiving means.
a and Ib are obtained. Therefore, the detection current can be logically configured as follows for focus detection. That is, as the focus error (hereinafter abbreviated as FE) detection logic, FE = {(IA + Ia)-(IB + Ib)} ... (Equation 1) Further, the light receiving means 67A and the light receiving means 67a are turned off.
It is also possible to connect on the E element 63. As a result, the sum of both light receiving means can be newly expressed as IA. Similarly, when the light receiving means 67B and the light receiving means 67b are connected, the sum of both light receiving means can be newly expressed as IB. Therefore, FE = IA-IB ... (Equation 2) is obtained by substituting it into Equation 1 and arranging it.

The use of the FE detection logic according to Expression 2 brings about the following effects. Originally, the grating A41 and the grating B42 are arcuate regions facing each other in the tangential direction of the third diffraction grating 40. Therefore, the integrated optical member 20
Suppose that thermal expansion occurs due to the heat generated by the laser element 13, since the grating A41 and the grating B42 are arranged apart from the center of the third diffraction grating 40, the thermal expansion causes the largest positional change. Cheap. However, the light receiving means 67A, B, a, and b for receiving the diffracted light from the grating A41 and the grating B42 are arranged in reverse order to take the sum, and the difference of the reverse forward sums (crossing differential) is detected by the FE detection logic. Therefore, the drift or offset of the detection signal caused by the position change described above is canceled by the mathematical expression 2.

Further, the remaining divided area, which is the central divided area, is further divided into two (that is, four divided areas) by a dividing line parallel to the tangential (track tangent line: Y axis) direction of the optical disk 6, and each of them is divided into four areas. Lattice C43 and Lattice D
44. That is, the regions of the lattice C43 and the lattice D44 are formed in a substantially D shape. In other words, the dividing line of the third diffraction grating 40 is formed in an H shape. The area of the grating C43 and the area of the grating D44 are equal, and the third diffraction grating 40
Approximately 1/4 of the total area of the
41 to the area of the grating D44 are respectively the third diffraction grating 40
Corresponding to approximately 1/4) of the entire area.

By constructing the areas of the lattices A41 to D44 as described above, the respective lattices (A41 to A41)
When the power of the light beam incident on D44) is integrated with respect to the area of each grating, each grating receives almost the same amount of optical power.

Similarly, the diffracted light of the three backward beams diffracted by the grating C43 is focused on the light receiving means 67C, the light receiving means 67E, and the light receiving means 67G provided on one side of the light receiving means 67. Similarly, the diffracted light of the three backward beams diffracted by the grating D44 forms an image on the light receiving means 67D, the light receiving means 67F, and the light receiving means 67H provided on the other side of the light receiving means 67. These six types of light receiving areas are detected as three beams for tracking control.

Similar to the FE detection logic described above, it is possible to logically configure the detection current by the six types of lattice areas. That is, as a tracking error (hereinafter abbreviated as TE) detection logic, TE = IC-ID-k {(IE + IG)-(IF + IH)} (Equation 3) (where k is a constant determined according to the operation setting) ) Is obtained.

The use of the TE detection logic according to Expression 3 has the following effects. First, the light receiving means 67C,
Since 67D detects the main beam, the first and second terms of Equation 3 are normal TE detections.

Next, the third term expressed in the brackets of Equation 3 is
This means to obtain the sum of the respective sub-beam detection currents obtained from the grating C43 and the grating D44 of the third diffraction grating 40 and perform the differential operation. Therefore, similarly to the above-mentioned FE detection logic, the drift or offset of the detection signal caused by the above-mentioned position change is canceled by the mathematical expression 3.

Particularly, since the grating A41 and the grating B42 are divided into arcuate regions, the light receiving means 67A of the two-divided light receiving means.
And light receiving means 67B and light receiving means 67a and light receiving means 67
The incident shape with respect to the sensor area of b can be distributed without waste. Similarly, since the grating C43 and the grating D44 are divided into D-shaped regions, it is possible to distribute the incident shape of the independent light receiving means 67C to the sensor area of the light receiving means 67H without waste. In addition,
Since the area from the grating A41 to the grating D44 is configured to divide the entire region of the third diffraction grating 40 into four equal parts, the third diffraction grating 40 can be easily formed.

Further, by adopting the above-mentioned region division structure of the diffraction grating, (IA + IB) + (Ia + Ib) ≈ (IC + ID) (Equation 4) RF signal detection and FE and TE signals Light power can be supplied in a well-balanced manner for detection.

The details of the operation setting in this embodiment will be described. The constant k is expressed as k = (IC + ID) / (IE + IF + IG + IH) (Equation 5), and usually the amplification factor when OE converting each light receiving means is adjusted so that k≈1.0. . Here, as described above, in the three beams formed by the first diffraction grating 22, the optical power of the main beam of the 0th-order light is 10
The ratio is such that the optical power of the sub-beams of the ± first-order light is 1.

Therefore, in order to satisfy the condition of k.apprxeq.1.0 by substituting the ratio of the optical powers into the respective light receiving means of the above formula 5, the light receiving means 67E, 67B are compared with the amplification degree of the light receiving means 67A, 67B. The amplification of 67F, 67G, and 67H is about 5
Setting it to double will solve the problem.

However, in particular, the area to be detected by the sub-beam is easily affected by crosstalk, and TE
The signal may reduce the SN ratio or increase the servo offset. Therefore, it is desirable to adjust the amplification factor of 5 times without increasing it as much as possible.

Therefore, in order to satisfy these conditions, 3
A modified example of the gratings A41 to D44 utilizing the characteristics of the beam will be described. FIG. 6 is a diagram for explaining the relationship between the modified example of the lattice and the OE element. In FIG. 6, reference numeral 70 denotes a third diffraction grating, which corresponds to the third diffraction grating 40 shown in FIGS. 3 and 5. Therefore, 67 is the same as the light receiving means 67 in FIG. Lattice A71, Lattice B72, Lattice C7
3 and the grid D74 are respectively the grid A4 in FIG.
1 to each of the grids D44. The same applies to the directions of the dividing lines from the grid A71 to the grid 74 (radial direction X, tangential direction Y).

The difference is that a separation grating A75 corresponding to the grating C73 is provided in the area of the grating A71. Similarly, the separation grid B76 corresponding to the grid C73 is replaced with the grid B72.
, The separation grating C77 corresponding to the grating D74 is provided in the area of the grating A71, and the separation grating D78 corresponding to the grating D74 is provided in the area of the grating B72. Then, the grid C73, the separation grid A75, and the separation grid B
76 diffracts in the same direction (in other words, the same OE element position), and the grating D74, the separation grating C77, and the separation grating D78 diffract in the same direction (similarly, the same OE element position). A separation grating D78 is formed from each separation grating A75. The separation gratings A75 to D78 have the same area and the same diffracted light power conditions.

The operation is verified by applying the above conditions to each detection signal. As described above, the grid C73 and the separation grid A
75 and the separating grating B76 diffract in the same direction,
Light diffracted by the grating C73 of the main beam enters the light receiving means 67C. At the same time, the diffracted light from the main beam separation grating A75 and the separation grating B76 enters the light receiving means 67C. Similarly, the diffracted lights of the sub-beams of the ± first-order lights are incident on the light receiving means 67E and 67G, respectively. Similarly, since the grating D74, the separation grating C77, and the separation grating D78 are diffracted in the same direction, the light diffracted by the grating D74 of the main beam enters the light receiving means 67D. At the same time, the light diffracted by the separation grating C77 and the separation grating D78 of the main beam enters the light receiving means 67D. Similarly, the diffracted lights of the sub-beams of the ± first-order lights are incident on the light receiving means 67F and 67H, respectively.

Considering the above incident conditions, equations 1 and 2
The FE signal at 1 does not affect the FE detection function because the areas where the separation gratings are provided are equal. The TE signal in Expression 3 does not affect the TE detection function because the areas where the separation grating is provided are the same in the first term, the second term, and the third term of the bracket.

Next, Formula 4 will be verified. Since each of the separation grating A75 to the separation grating D78 corresponds to the peripheral area of the third diffraction grating 70, the influence on the main beam of the 0th-order light is small, and the condition of Expression 4 is maintained with little influence. In Eq. 5, similarly, the molecule remains almost unaffected. On the other hand, since the optical power of the ± 1st-order light sub-beams is incident on the peripheral region of the third diffraction grating 70, in addition to the optical powers of the grating C73 and the grating D74,
The optical powers of the separation grating A75 and the separation grating D78 are added. And the denominator increases. As a result, the light receiving means 6
The amplification of 7E, 67F, 67G, and 67H can be set much lower than 5 times. Therefore, it is possible to realize a signal detection operation that is unlikely to be affected by crosstalk.

The overall operation of the composite element 2 configured as above will be described with reference to FIG. FIG. 7 is an operation explanatory diagram of the composite element 2. First, a required connection is made to the lead 18, so that the laser element 13 emits the diffused light 1 from the light emitting point 19.
01 is emitted. Then, it passes through the cover glass 17 and enters the first light guide member 21.

In the first light guide member 21, unnecessary ambient light or light spread over a predetermined diffusion angle is absorbed by the light absorption film 23, and the diffused light 10 is diffused by the first diffraction grating 22.
1 is converted into three-beam outward light 102.

The outward light 102 is transmitted from the first light guide member 21 to the second light guide member 21.
It is incident on the light guide member 25. The outward light 102 traveling in the second light guide member 25 reaches the slope 26. Most of the outgoing light 102 is transmitted through the round trip separation film 28,
It is incident on the light guide member 35. Further, the light is transmitted through the transparent surface 38 of the third light guide member 35, and the optical disc 6 is reflected by the mirror 4.
The path is changed toward, and the light is converged by the objective lens 5 and enters the optical disc 6.

Outgoing light 1 which is diffused light reaching the slope 26
Outgoing light 102 in a region of 02 that does not contribute to reproduction / recording
Is incident on the second diffraction grating 27. Then, it becomes the monitor reflected diffracted light 103 of the convergent light, and advances to the side surface reflection film 32,
The light is reflected again and penetrates through the second light guide member 25 and the third light guide member 35 to be emitted from the emission surface 39. The monitor reflected diffracted light 103 forms an image on the optical power detection means 66 of the light receiver 60. In this way, since the forward light 102 in a region which is a part of the forward light 102 and does not contribute to the reproduction / recording is used for the detection of the optical power, the optical power which is accurately proportional to the optical power of the laser element 13 is detected. In addition, it is possible to provide an extremely excellent front monitor system that does not affect the original reproduction and recording by the light amount.

Next, the backward-path light 104 reflected from the recording layer of the optical disk 6 enters the transmitting surface 38 of the third light guide member 35 through the objective lens 5 and the mirror 4 in the reverse order. Return light 10
4 is reflected by the round-trip separation film 28 and travels to the third diffraction grating 40 of the third light guide member 35. Third diffraction grating 40
Then, the return reflection diffracted light 105 whose main component is the + 1st order diffracted light
Becomes The backward reflection diffracted light 105 is reflected again by the auxiliary reflection film 30 of the second light guide member 25, and is emitted from the exit surface 39 to the light receiver 6
Eject toward 0. Moreover, each lattice A41
From the light receiving means 67A to the return light diffracted light 105 reflected from the grating area of the grating D44 from the respective light receiving means 67A.
Form an image on H. In this way, focus control and tracking control can be performed by combining the detection signals of the light receiving means 67A to the light receiving means 67H.

[0060]

As described in detail above, according to the optical pickup device of the present invention, the general-purpose light emitting element can be used to make the optical pickup device compact and inexpensive, and to assemble it with high precision. Thus, it is possible to provide an optical pickup device capable of accurately and efficiently detecting the optical power of the light emitting element.

Further, even if the integrated optical member undergoes thermal expansion under the influence of heat generated by the laser element, the light receiving means are arranged in reverse order to take the sum, and the difference of the reverse forward sums (crossing differential). Since the above is the FE detection logic, the drift or offset of the FE detection signal caused by the position change due to the thermal expansion is canceled by the mathematical expression 2.
Similarly, the drift or offset of the TE detection signal caused by the position change due to the above-described thermal expansion is canceled by the mathematical expression 3.

Particularly, since the grating A and the grating B are divided into arcuate regions and the grating C and the grating D are divided into D-shaped regions, the incident shape for each sensor area of the light receiving means is distributed without waste. You can also do it.

In addition, since the areas of the gratings A to D are divided into four equal parts in the entire area of the third diffraction grating, the diffraction grating can be easily formed. further,
Separation grating A and separation grating B corresponding to grating C are provided in the areas of grating A and grating B, and separation grating C and separation grating D corresponding to grating D are provided in the areas of grating A and grating B, respectively. is there.

In this way, the integrated optical member capable of realizing the signal detecting operation which is hardly influenced by the crosstalk without being influenced by the fluctuation of the operating temperature, and the integrated optical member is used. optical pickup device, as well as to provide an optical disk equipment using the optical pickup device.

[Brief description of drawings]

FIG. 1 is a perspective view showing the entire optical pickup.

FIG. 2 is a perspective view showing the entire composite element.

FIG. 3 is an exploded perspective view of an integrated optical member.

FIG. 4 is an overall perspective view of a light receiver

FIG. 5 is a pattern diagram of the OE element viewed from the entrance.

FIG. 6 is a diagram for explaining the relationship between a modified example of the grating and the OE element.

FIG. 7 is an operation explanatory diagram of the composite element.

[Explanation of symbols]

1 Optical pickup 2 composite elements 3 light beams 4 mirror 5 Objective lens 6 optical disks 7 Actuator 8 carriage 10 light sources 11 General-purpose semiconductor laser 12 Base member 13 Laser device 16 Exit 17 cover glass 18 leads 19 light emitting point 20 Integrated optical member 21 First Light Guide Member 22 First diffraction grating 23 Light absorbing film 25 Second light guide member 26 slope 27 Second diffraction grating 28 Round trip separation membrane 29 Optical path effective area 30 Auxiliary reflective film 31 side 32 Side reflective film 35 Third Light Guide Member 36 First slope 37 Second slope 38 Transparent surface 39 Exit surface 40, 70 Third diffraction grating 41, 71 Lattice A 42, 72 lattice B 43, 73 Lattice C 44,74 Lattice D 45 Fourth Light Guide Member 46 slope 47 First side 48 Second side 60 light receiver 61 packages 62 entrance 63 OE element 64 lead terminals 65 flexible cable 66 Optical power detection means 67A to 67H light receiving means 75 Separation grid A 76 Separation grid B 77 Separation grid C 78 Separation grid D 101 diffuse light 102 outgoing light 103 Monitor reflected diffracted light 104 Return light 105 Return reflection diffracted light

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Fumikawa Furukawa 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Eizo Ono 1006 Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd. In-house (72) Inventor Jiro Sanma 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Toshihiro Koga 1006 Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd. (56 ) Reference JP-A-11-283271 (JP, A) JP-A-11-283272 (JP, A) JP-A-9-237434 (JP, A) JP-A-9-198706 (JP, A) JP-A 2-166630 (JP, A) JP-A-4-40634 (JP, A) JP-A-4-318331 (JP, A) JP-A-9-259454 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G11B ^7/ 09-7/22

Claims (3)

(57) [Claims] 1. An integrated optical member for guiding a luminous flux of a light emitting element to an optical disc and separating a necessary luminous flux from reflected light from the optical disc, wherein the integrated optical member is
Tracking control and focus control from the reflected light
It has a diffraction grating for extracting a necessary luminous flux, and the diffraction grating is
Divide into 3 by 2 dividing lines parallel to the radial direction of the optical disc
Center area and the tangential direction of the optical disc.
Divided into a first arcuate region and a second arcuate region that are separated
The central area is a dividing line parallel to the tangential direction.
Then, in the first substantially D-shaped region and in the second substantially D-shaped region
The tangier of the first substantially D-shaped region is divided.
In the first arcuate region laterally in the vertical direction and in the second region.
A first separating grid and a second separating grid in each of the arcuate regions of
A grid, further comprising the tongue of the second substantially D-shaped region
In the first arcuate region laterally in the direction of the mental direction and in the
Within the second arcuate region there are respectively a third separating grid and a fourth separating grid.
An integrated optical member comprising a separation grating. 2. A light emitting device and the integrated optical member according to claim 1.
A light receiving means for receiving light and converting it into an electric signal;
The light emitting element, the integrated optical member, and the light receiving means are mutually connected.
Optical pickup device having coupling means for holding the position
And the light receiving means includes a first substantially D-shaped region and a first substantially D-shaped region.
And receive the diffracted light from the second separation grating and the second separation grating.
Three light receiving means, a second substantially D-shaped region and a third separating case
Child and the fourth diffracted light of the fourth separation grating
An optical pickup device comprising optical means. 3. An optical pickup device according to claim 2 is used.
An optical disk device characterized by being used.