JP3094787B2 - Optical pickup, optical element and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical pickup for recording or reproducing information on or from an optical element or an optical disk, an optical element, and a method of manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, it has been desired to reduce the size of an optical disk device for recording and reproducing information using laser light, and attempts have been made to reduce the size and weight of an optical pickup by reducing the number of optical components. Have been done. Small optical pickup
The reduction in weight is advantageous not only for reducing the size of the entire apparatus, but also for improving the performance such as shortening the access time. In recent years, use of a hologram optical element has been cited as a means for reducing the size and weight of an optical pickup, and some of them have been put to practical use.

A conventional example of an optical pickup using a hologram optical element will be described below with reference to FIGS. 26 to 29. FIG. 26A is a plan view of a conventional optical pickup, and FIG. 26B is a side view of the conventional optical pickup.

First, from a semiconductor laser as a light emitting element,
The optical path on the outward path to the optical disk will be described. FIG.
In FIG. 6B, the laser light 3 horizontally emitted from the semiconductor laser chip 2 horizontally mounted on the sensor substrate 1 is similarly mounted on the sensor substrate 1 so that the reflection surface faces the semiconductor laser chip 2. The second surface 5 of the transparent light guide member 5 is formed by the trapezoidal reflection prism 4.
b, the diffused light 7 entering the light guide member 5 through the entrance window 6
become. A hologram 8 is formed on the first surface 5 a of the light guide member, and the diffused light 7 is emitted from the hologram 8 to the outside of the light guide member 5 to become a diffused light 9. The diffused light 9 enters the objective lens 10 and is converted into forward-path condensed light 13 that converges as a spot 12 on the information recording layer 11a of the optical disc 11.

Next, the return path from the optical disk to the light receiving sensor will be described. The reflected light 14 reflected by the information recording layer 11a of the optical disc 11 enters the objective lens 10 again, is converted into the return path focused light 15, and then enters the hologram 8.

[0007] The hologram 8 has two equal-area regions having different patterns, each of which is divided by a dividing line in the same direction as the track direction of the optical disk 11 as shown in FIG. (2n + 1) π such as 45 ° and 135 ° with respect to the polarization direction of the laser chip 2
The light is converted into a first diffracted light 16 and a second diffracted light 17 diffracted in different directions having an angle of / 4.

On the second surface 5b of the light guide member 5, a first return polarization splitting section 18 coated with a return polarization splitting film that transmits the P-polarized light components of the two diffracted lights 16 and 17 and reflects the S-polarized light component. And a second return polarization splitting section 19.

In FIG. 26 (a), the polarization state of the diffused light 7 incident on the hologram 8 is represented by a linearly polarized light 2 indicated by an arrow.
3, the diffraction directions of the two diffracted lights 16 and 17 are set to (2n + 1) π / 4 with respect to the polarization direction of the linearly polarized light 23. Reference numerals 16 and 17 denote the P-polarized light component and the S-polarized light component respectively about half those of the two return polarization splitters 18 and 19, and the first transmitted light 24 and the second transmitted light 25 from the two return polarization splitters 18 and 19. The light amounts are the first diffracted light 16 and the second diffracted light 17, respectively.
About half of The two transmitted lights 24 and 25 irradiate a first light receiving sensor 26 and a second light receiving sensor 27 formed on the sensor substrate 1, respectively. The first reflected light 28 and the second reflected light 29, which are approximately the other half of the two diffracted lights 16 and 17 reflected by the two returning polarization splitters 18 and 19, respectively, are the first returning reflection part 30 of the first surface 5a. And the third reflected light 32 and the fourth reflected light 3 reflected by the second return-path reflecting section 31 and traveling again to the second surface 5b.
It becomes 3. The third reflected light 32 and the fourth reflected light 33 are
After passing through the first transmission window 34 and the second transmission window 35 of the second surface 5b, respectively, it becomes the third transmission light 36 and the fourth transmission light 37, respectively.
And irradiates the fourth light receiving sensor 39. Both diffracted lights 16,
Numeral 17 is designed so that a focal point exists between the two return-path polarization separation units 18 and 19 and the third and fourth light receiving sensors 38 and 39, respectively.

The principle of detecting a magneto-optical signal will be described in detail with reference to FIG. In FIG. 28, 23 is the polarization direction of the linearly polarized light incident on the hologram 8 as described above. Since the hologram 8 does not affect the polarization plane, the optical disk 1
If no information is recorded on the first information recording surface 11a (if the information recording surface 11a is not magnetized), the two diffracted lights 16, 17 which are the reflected light of the spot 12 are also linearly polarized light 2
3 has the same polarization direction. The polarization directions of the two diffracted lights 16 and 17 in such a state are shown in FIG. 26 with respect to the two return polarization separation units 18 and 19 which transmit the P-polarized component almost 100% and reflect the S-polarized component almost 100%. Azimuth 45
The diffraction directions of the two diffracted lights 15 and 16 are set to 45 ° and 135 ° with respect to the polarization direction of the linearly polarized light 23 so that they are incident at ゜ and 135 °. The linearly polarized light 23 is the optical disk 11
When the light is reflected by the magnetized information pit, the direction of rotation changes within a range of ± θk depending on the polarity of the magnetization and the strength of the magnetization (Kerr effect).

Now, the state of rotation of θk from the state of linearly polarized light 23 is linearly polarized light 40, and the state of rotation of −θk is linearly polarized light 4
Let it be 1. Consider a case where a magneto-optical signal modulated from linearly polarized light 40 to linearly polarized light 41 is incident on the polarization splitting films of both polarization splitting sections 18 and 19.

When the polarization state of the return path focused light 15 is rotated by θk from the state of the linearly polarized light 23, the first diffracted light 16
Is modulated into linearly polarized light 40, and the polarization state of the second diffracted light 17 is modulated into linearly polarized light 41. Also return light 1
When the polarization state of the first diffracted light 16 is rotated by -θk from the state of the linearly polarized light 23, the polarization state of the first diffracted light 16 is changed to the linearly polarized light 4
First, the polarization state of the second diffracted light 17 is modulated into linearly polarized light 40. Accordingly, the P-polarized light component of the second diffracted light 17 is equal to the S-polarized light component of the first diffracted light 16, and the S-polarized light component of the second diffracted light 17 is equal to the P-polarized light component of the first diffracted light 16. Therefore, the RF reproduction signal is the first diffracted light 1
6, the sum signal of the signal of the S-polarized component of the second diffracted light 17, the sum signal of the signal of the S-polarized component of the first diffracted light 16, and the signal of the P-polarized component of the second diffracted light 17. In other words, the signal component is doubled by the following equation (1), and the noise of the same phase component is canceled, so that a signal with a high C / N ratio is obtained as a result.

Input / output of various signals to / from the sensor substrate 1 on which the semiconductor laser chip 2 and the light receiving sensor group are formed is performed via a lead frame 44.

Next, the first light receiving sensor 2 will be described with reference to FIG.
6, the shapes of the second light receiving sensor 27, the third light receiving sensor 38, and the fourth light receiving sensor 39, and the signal detection principle will be described.

The second light-receiving sensor 27 and the fourth light-receiving sensor 39 are three-divided sensors.
b, 27c and 39a, 39b, 39c. Here, the outputs from the first light receiving sensor 26 and the third light receiving sensor 38 are represented by I26 and I38, respectively, and the respective portions 27a, 27b, 27c and 39a, 3a, 3a and 3a of the second light receiving sensor 27 and the fourth light receiving sensor 39.
9b and 39c are output from I27a and I27, respectively.
b, I27c and I39a, I39b, I39c.

First, of various signals, an RF reproduction signal (R.
F. ) Will be described. As described above, the P of the diffracted light 16
Since it is obtained by the differential between the sum signal of the polarized light component and the S-polarized light component of the diffracted light 17 and the sum signal of the S-polarized light component of the diffracted light 16 and the P-polarized light component of the diffracted light 17, the circuit shown in the circuit diagram of FIG. As can be seen from the configuration, it is obtained by the following equation 1.

(Equation 1) F. = [I26- (I27a + I27b + I27
c)]-[I38- (I39a + I39b + I39
c)] Next, the focus error signal (FE) will be described. F. E. FIG. Is obtained by the following equation 2 as can be seen from the circuit configuration of the circuit diagram of FIG.

(Equation 2) E. FIG. = [(I27a + I27c) + I39b]-
[(I39a + I39c) + I27b] Now, the spot 12 of the objective lens 10 is accurately focused on the information recording layer 11a of the optical disc 11 and is on the second light receiving sensor 27 and the fourth light receiving sensor 39 in this focused state. The irradiation shape of the laser beam is 45a, 4
Assuming 6a, the irradiation intensity distribution of the laser beam and the positional relationship between the light receiving sensors are adjusted so as to obtain the following Expression 3.

(Equation 3) E. FIG. = 0 Next, when the distance between the optical disc 11 and the objective lens 10 is close from the in-focus state, the irradiation shapes of the laser beams on the second light receiving sensor 27 and the fourth light receiving sensor 39 are 45c and 46c, respectively. , F. E. FIG. Changes as in Equation 4.

(Equation 4) E. FIG. > 0 Conversely, when the distance between the optical disc 11 and the objective lens 10 is far from the in-focus state, the irradiation shape of the laser light on the second light receiving sensor 27 and the second light receiving sensor 39 becomes 45
b, 46b; E. FIG. Changes as in Equation 5.

(Equation 5) E. FIG. <0 The above focus error detection method is known as a spot size method.

Next, a tracking error signal (TE)
Will be described. 2 different patterns of hologram 8
Since the boundary between the two areas having the same area is in the same direction as the track direction, the track information included in the reflected light from the optical disk 11 is divided by the hologram 8 into the right and left track information divided by the center line of the spot 12 in the track direction. And the two track information are the first diffracted light 16
And the second diffracted light 17. Further, the hologram is designed so that the diffraction efficiency of the first diffracted light 16 and the second diffracted light 17 in each region of the hologram 8 for the first diffracted light 16 and the second diffracted light 17 is equal.
Therefore, T. E. FIG. Is obtained from the following Equation 6 as can be seen from the circuit configuration of the circuit diagram of FIG.

(Equation 6) E. FIG. = [(I27a + I27b + I27c) + (I
39a + I39b + I39c)]-(I26 + I38) When the spot 12 irradiates the center of the track, the amount of the return path focused light 15 incident on the two regions of the hologram is equal, so the amounts of the first diffracted light 16 and the second diffracted light 17 And the sum signal of the signal of the first light receiving sensor and the signal of the third light receiving sensor, and the sum signal of the signal of the second light receiving sensor and the signal of the fourth light receiving sensor, which are the light amounts of the two diffracted lights 16 and 17, are equal. T. E. FIG. Is as shown in the following Expression 7.

(Equation 7) E. FIG. = 0 When the spot 12 on the optical disk surface is eccentric in the direction of 90 ° from the center of the track with respect to the track, the amount of the return path focused light 15 incident on the hologram 8 is different between the two regions of the hologram 8. The sum signal of the first light receiving sensor signal and the third light receiving sensor signal, which is the light amount of the diffracted light 16, is equal to the sum signal of the second light receiving sensor signal and the fourth light receiving sensor signal, which is the light amount of the second diffracted light 17. Disappeared, T. E. FIG. Is represented by the following Expression 8 or Expression 9.

(Equation 8) E. FIG. > 0 (Equation 9) E. FIG. <0 This tracking error detection method is known as a push-pull method.

As described above, the hologram 8 is divided into two different patterns with the dividing line in the same direction as the track direction as a boundary.
A tracking error signal can be obtained by dividing the hologram 8 into two equal areas and designing the two areas of the hologram 8 so that the diffraction efficiencies for both the diffracted lights 16 and 17 are equal.

Further, Japanese Patent Application Laid-Open Nos. Hei 5-258382 and Hei 5-
When manufacturing the optical pickup of No. 258386, an optical guide member having an optical function element provided at each boundary is formed.
After forming the bonded assembly block, a slope is formed, a polarizing film is formed, and the film is cut with a predetermined width to form an optical pickup element .

[0027]

However, in the above-described conventional configuration, the C / N of the RF signal deteriorates due to the following problems.

A hologram is used for round-trip separation, but the 0th-order diffracted light is used on the outward path and the 1st-order light is used on the return path, and the pitch of the hologram is small due to the restriction of the incident angle to the polarization separation section. It is difficult to suppress the generation of -1st-order diffracted light due to the hologram, and the first-order diffraction efficiency of the S-polarized light component is lower than the first-order diffraction efficiency of the P-polarized light component. There is a limit in improving the efficiency, and the light amount loss in the hologram is large.

Since the RF signal is also detected by the divided light receiving sensor for detecting the focus error signal, a light amount loss occurs in the dead zone of the dividing section.

The enhancement effect of enlarging the apparent Kerr rotation angle cannot be obtained because a beam splitter having polarization selectivity is not used.

Further, the focus error signal and the tracking error signal are deteriorated due to the following problems.

The focus error signal is detected based on the spot size of the P-polarized light and the spot size of the S-polarized light on the light-receiving sensor. An offset occurs in the focus error signal.

Since the tracking error signal is detected by push-pull, it is easily affected by the depth of pits and grooves on the optical disk.

When a tracking error signal is detected by a three-beam method using a diffraction grating, crosstalk between a main beam and a side beam occurs due to a large spot size on a light receiving sensor.

When manufacturing the optical pickup disclosed in Japanese Patent Application Laid-Open Nos. 5-258382 and 5-258386, the number of elements that can be removed from one collective block in the longitudinal direction of the optical guide member is reduced. Is determined,
In addition, since the device has a slope, it is difficult to arrange the same device in the lateral direction, and the number of devices to be obtained is small and productivity is low.

[0036]

SUMMARY OF THE INVENTION The present invention has been devised in order to solve the problems of the prior art described above, and includes a light emitting element and an image forming means for forming light from the light emitting element on a disk. Imaging means, a polarization-selective beam splitter film,
An analyzer having a polarization splitting function, an analyzer incident light polarization conversion element for converting a polarization state of incident light to the analyzer into linearly polarized light of about 45 °, and a focus error detection element having a function as focus detection means. A light-emitting element that emits linearly polarized light and a light-receiving element including a plurality of light-receiving sensors installed on a sensor substrate, and return light from the disk board that has passed through the imaging means is transmitted to the light-emitting element by the polarization beam splitter film. After the light is separated from the light from the optical disk, the return light from the separated disk is incident on the focus error detection element and the analyzer incident light polarization conversion element. The light passing through the analyzer incident light polarization conversion element is made incident on the analyzer, and the P-polarized component light and S
After being separated into polarized light components, each component light is received by a light receiving sensor, and an RF signal is detected by differential amplification. On the other hand, the light incident on the focus error detecting element is converted into light for focus detection and received by a light receiving sensor.

A constituent body having an optical thin film provided on a substrate is formed, a plurality of the constituent bodies are prepared, and the optical thin films are joined so as to be sandwiched between bases to form a collective constituent body. Cut at an angle to the joint surface.

[0038]

According to the present invention, the polarization state of the return light from the disk is converted into linearly polarized light of about 45 ° by the action of the analyzer and the polarization conversion element, and the polarized light enters the polarization separation means .
You. The linearly polarized light of about 45 ° has a P-polarized light component and an S-polarized light component of about 50% each by the polarization separation means, and is split into 50% of the light by a light-receiving sensor that receives each component . Both <br/> photosensors removing in-phase noise component other than the magneto-optical signal by differentially amplifying. Further, since the light receiving sensor for detecting the RF signal detects only the RF signal, the two light receiving sensors do not need to be divided, so that the light amount loss due to the dead zone is eliminated, and the light from the light emitting element and the return light from the disk are separated. Therefore, an RF reproduction signal having a high C / N ratio can be obtained by increasing the apparent Kerr rotation angle by using a beam splitter film having polarization selectivity . Furthermore, since the return error light is guided to the focus error detection element having a function as the focus detection means without separating the P-polarized component and the S-polarized component from the disc disk and the focus error signal is detected , birefringence and Even if the light amount ratio between the P-polarized light and the S-polarized light of the return light from the disk disk changes due to a car rotation or the like, no offset occurs in the focus error signal. Also, when a tracking error signal is detected by the three-beam method, the spot size on the sensor can be reduced, and the occurrence of crosstalk between the main beam and the side beam can be suppressed.

Further, by joining a plurality of components to form an aggregate component and cutting it at an angle to the joining surface, the number of steps can be reduced and productivity can be improved.

[0040]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to the drawings. FIG. 1A is a front view of an optical pickup according to a first embodiment of the present invention, and FIG. 1B is a side view of FIG. 1A according to the first embodiment of the present invention.

In FIG. 1B, a laser beam horizontally emitted from a semiconductor laser chip 103 horizontally mounted on a substrate 101 via a submount 102 is a trapezoidal prism similarly mounted on the substrate 101. 10
The light is reflected by 4 and the optical path is bent to become diffused light. This diffused light is divided into 0th-order diffracted light (main beam) and ± 1st-order diffracted light (side beam) by a transmission type diffraction grating 106 formed on the second surface 105b of the light guide member 105.

The main beam and the side beams pass through the first polarization beam splitter film 108 having the first polarization selectivity formed on the first inclined surface 107a of the light guide member, and pass through the first surface 105a of the light guide member. , Objective lens 10
9 and is focused on the information recording surface 111 of the optical disk 110 by the condensing action of the objective lens. At this time, the image spots 112 and 114 of the two side beams are formed on the information recording surface 111 at symmetrical positions with respect to the image spot 113 of the main beam. On the information recording surface 111, information recording or reproducing signals, tracking, and focusing, so-called servo signals, are read out by the imaging spots 113, 112, and 114 of the main beam and the side beams. The return light of the main beam and the side beam reflected by the information recording surface 111 of the optical disk board 110 passes through the objective lens 109 and the first surface 105a of the light guide member 105 again, and is formed again on the first slope 107a of the light guide member. The light enters the first polarized beam splitter film 108.

The first polarizing beam splitter film 108 has a constant transmittance for light having a vibration component parallel to the plane of incidence (hereinafter simply referred to as a P-polarized component), and has a vertical vibration component (hereinafter simply referred to as a P-polarized component). About 1 for the S-polarized component)
It has a reflectance of 00%.

The reflected light from the first polarizing beam splitter film 108 is applied to a second polarizing beam splitter film 117 (second polarization selectivity) formed on a second inclined surface 107b of the light guide member 105 parallel to the first inclined surface 107a. Incident on the beam splitter film having the same).

Here, the second polarization beam splitter film 11
A description will be given of the reflected light 122 among the light fluxes incident on the light-receiving element 7.

The reflected light 122 is transmitted to the first
First polarizing beam splitter film 108 on slope 107a
Then, the light enters a parallel light conversion element 125 formed on the same plane as the light, is converted into a parallel light 123, and then passes through a half-wave plate 126 laminated on the second inclined surface 107b. The transmitted light has its polarization plane rotated by 45 ° by the half-wave plate 126 and the third slope 1 parallel to the first slope 107 a of the light guide member 105.
07c, the S-polarized light component is converted into an S-polarized light beam 115 by the polarization separation film 124, and the second surface 105b of the light guide member 105b.
Sensor substrate 116 formed on substrate 101
Reach The transmitted light 128 of the P-polarized light component is transmitted by the fourth light guide member parallel to the first slope 107 a of the light guide member 105.
The light guide member second surface 105 is reflected as a P-polarized light beam 119 by the reflection film 118 formed on the inclined surface 107d.
b and the sensor substrate 11 formed on the substrate 101
Reach 6.

The principle of detecting a magneto-optical signal will be described in more detail with reference to FIGS. Obtain high quality RF playback signal, C / N
In order to increase the power, a structure provided with an enhancement structure for apparently amplifying the Kerr rotation angle θk is being sought. In this embodiment, a first polarization beam splitter film 108 having an enhanced structure is provided on the first slope 107a, and a second polarization beam splitter film 117 is provided on a second slope 107b parallel to the first slope.

In FIG. 2, an arrow 150 indicates the polarization direction of the linearly polarized light before being incident on the information recording surface 111 of the optical disk 110 of FIG. Information recording surface 1 of optical disk board 110
If the information is recorded on the optical disk 11, the polarization state of the reflected light from the optical disc 110 is rotated by ± θk in accordance with the magnetization direction of the recording information surface 111. θk is called a Kerr rotation angle.

Now, let us assume that the state rotated by θk from the state of the linearly polarized light 150 is linearly polarized light 151, and the state rotated by −θk is 152. The reflected light passes through the first surface 105a of the light guide member, and then enters the first polarization beam splitter film 108 formed on the first slope 107a. The first polarizing beam splitter film 108 has a constant transmittance for P-polarized light and a reflectance of almost 100% for S-polarized light. Therefore, the linear polarization direction in FIG. Polarized light 151
Becomes 153 when rotated by θk ′, and the linearly polarized light 152 rotated by −θk becomes 154 when rotated by −θk ′, and the Kerr rotation angle θk becomes apparently large. Second slope 1
07b formed on the second polarizing beam splitter 11
The same occurs for the reflected light 122 reflecting the light 7 and the linearly polarized light 153 is rotated in the direction of the linearly polarized light θk ′.
Is 155 when rotated by θk ″, and the linearly polarized light 154 rotated by −θk ′ becomes 156 when rotated by −θk ″, and the Kerr rotation angle θk further increases in appearance. As a result, the light reflected by the parallel light conversion element 125 and incident on the half-wave plate 126 is
As a result, the polarization direction in FIG. 2 rotates 45 ° as shown in FIG. 3 and reaches the sensor substrate 116 via the above-described optical path.

FIG. 4 is a diagram illustrating the shape of a light receiving sensor of an optical pickup and a signal processing circuit according to a first embodiment of the present invention. The first light receiving sensor 170 receives the P-polarized light beam 119 and the P-polarized light component is as shown in FIG. 3 as a P-polarized light component signal 161, and the second light-receiving sensor 171 receives the S-polarized light beam 115 and receives the S-polarized light component. S in FIG.
It looks like a polarization signal 162. This S-polarized signal 162 and P
The polarization signal 161 is 180 degrees out of phase. By performing differential amplification of both signals, the signal component is doubled, and an RF reproduction signal in which noise of the same phase component is canceled can be obtained.

Therefore, if the RF reproduction signal (RF) is a photocurrent I170 detected by the first light receiving sensor 170 and a photocurrent I171 detected by the second light receiving sensor 171, it is detected by the following equation (10).

(Equation 10) F = I170-I171 Next, a description will be given of the internally transmitted light of the light beam incident on the second polarizing beam splitter 117. The transmitted light 120 enters the focus error detection element 121 on the fourth slope 107d. In this embodiment, an astigmatism generating element is formed as the focus error detecting element 121. The astigmatism generating element may be a hologram or a lens.

The detection of a focus error signal by the astigmatism method and the state of astigmatism in the present embodiment will be described with reference to FIGS.

FIGS. 5 (a), 5 (b) and 5 (c) show the optical disk 11 when the optical disk 110 is in the in-focus position.
When 0 approaches the focal point, the optical disk 110
FIG. 3 is an external view of an astigmatism light beam when is moved away from a focus position. 5D, 5E, and 5F, respectively.
Focus error detecting element 12 in the cases of (a), (b) and (c)
The third light receiving sensor 172a, 1
The spot shapes on 72b, 172c, and 172d are shown.

The focus error detecting element 121 is the optical disk 1
When 10 is at the in-focus position, a first focal point 177 is generated upstream of the third light receiving sensor 172 and a second focal point 178 is generated downstream of the third light receiving sensor 172, and FIG.
As shown in (e) and (f), taking the x-axis direction and the y-axis direction, a line image in the y-axis direction is formed at the position of the first focal point 177, and a line image on the x-axis is formed at the position of the second focal point 178. Will be tied.
When the optical disc 110 is at the in-focus position, the focus error detecting element 121 is designed at a position where the respective imaging diameters in the x-axis and y-axis directions generated by the astigmatism become equal to form a circular spot shape.

The focus error signal is obtained by converting the photocurrents from the third light receiving sensors 172a, 172b, 172c, 172d into I172a, I172b, I172c, I1 respectively.
If it is 72d, it can be expressed by the following equation 11 as can be seen from the circuit diagram of FIG.

(Equation 11) E. FIG. = (I172a + I172b)-(I172c
+ I172d) When the optical disk board 110 is in the in-focus position, FIG.
As can be seen from (a) and (d), since the respective image forming diameters in the x-axis and y-axis directions are equal to form a circular spot shape, the total amount of received light at 172a and 170b and 172c and 17
Since the total amount of received light at 0d is equal, the focus error signal is given by the following equation (12).

(Equation 12) E. FIG. = 0 When the optical disc 110 approaches the focus position, FIG.
As shown in (b), the first focus 177 and the second focus 178 generated by the focus error detection element 121 are
The third light receiving sensor 172a, 17
The spot shapes on 2b, 172c and 172d are shown in FIG.
As shown in (e), the light beam becomes an elliptical light beam having a long axis in the y-axis direction, and the amount of light received by the focus detection sensors 172a and 172b is larger than the amount of light received by the focus light receiving sensors 172c and 172d. Becomes

(Equation 13) E> 0 When the optical disc 110 is separated from the in-focus position, FIG.
As shown in (c), the first focus 177 and the second focus 178 generated by the focus error detection element 121 are
The third light receiving sensor 172a, 172
The spot shapes on b, 172c and 172d are shown in FIG.
As shown in (1), the light beam becomes an elliptical light beam having a major axis in the x-axis direction, and the amount of light received by the focus detection sensors 172c and 172d is larger than the amount of light received by the focus light receiving sensors 172a and 172b.

(Equation 14) A focus error signal having E <0 or more is known as an astigmatism method. Further, a tracking detection method will be described with reference to FIGS.

FIG. 6 is a diagram showing the positional relationship between an image spot on an optical disk and an information track 180. FIG.
As shown in (b), the image spots 181 and 183 of the two side beams are the image spots 182 of the main beam.
Are positioned symmetrically with respect to the track direction with respect to the information track 180, and are slightly shifted in directions opposite to each other with respect to the information track 180. Now the side beam spot 18 in FIG.
Numerals 1 and 183 reach the sensor substrate 116 similarly to the optical path of the astigmatism method and enter the fourth light receiving sensors 176a and 176b of FIG. At this time, the photocurrents generated on the fourth light receiving sensor are denoted by I176a and I176, respectively.
b. Now, the information track 180 is focused on the imaging spot 18
When it is shifted to the left with respect to 2 as shown in FIG.
Since the imaging spot 183 is located almost on the information track, the intensity of the reflected light decreases. On the other hand, the imaging spot 181 deviates from the information track, and the reflected light increases. On the other hand, when the information track 180 is shifted to the right with respect to the imaging spot as shown in FIG. 6C, the opposite phenomenon occurs, the amount of reflected light of the imaging spot 181 decreases, and the The amount of reflected light at 183 increases.

Therefore, as can be seen from the circuit diagram of FIG. 4, if a circuit as shown in the following Expression 14 is constructed, a tracking error signal (TE) can be obtained.

(Equation 15) E. FIG. = I176a-I176b Next, a tracking detection method by the push-pull method will be described.

In the push-pull method, information on the track deviation of the image spot formed by the objective lens 110 is stored in the optical disk board 11.
+1 generated at the guide track and recording pit on the 0 surface
The tracking error signal is obtained by capturing the balance between the light amounts of the first-order diffracted light 184 and the minus first-order diffracted light 185.

The reflected light from the image forming spot 182 in FIG. 6 is formed on the sensor substrate 116 in the same manner as in the optical path of the astigmatism method. In the imaging spot 182 on the third light receiving sensor 172 in FIG. 4, the + 1st-order diffracted light 184 is received by the third light receiving sensor 172d, and the generated photocurrent is I172d, -172.
If the first-order diffracted light 185 is received by the third light receiving sensor 172c and the generated photocurrent is I172c, the tracking error signal (TE) becomes the third light receiving sensor 172c and 172c.
It is obtained from the output of d by the following equation (16).

(Equation 16) E. FIG. = I172c-I172d Next, an example of a method for manufacturing the present element will be described with reference to FIGS.

According to the present manufacturing method, the optical pickup according to the present invention is used as a minimum constituent block, and this is taken as a two-dimensional plane X′-Y ′.
An aggregate structure further including a plurality of plane blocks including a plurality of planes is formed by the first to third light guide members 105, 130, and 131, each optical function element formed on the plane, and a half-wave plate 126. It is characterized by being formed from aggregate blocks.

FIG. 7A shows first to third light guide members 105, 130, 131 and 1 forming a first assembly block.
/ 2 shows a side view before the wave plate 126 Ru bonded.

The fifth surface 107e of the first light guide member 105
The fifth joining reference marker 220e and the light guide member 10
5, the first polarization beam splitter film 108, the parallel light conversion element 125, and the first bonding reference marker 220a are formed on the first surface 107a of the second light guide member 130.
A second polarizing beam splitter 109 and a second joining reference marker 220b are formed on the first joining guide marker 105 and the second joining guide marker 220b using the first joining reference marker 220a and the second joining reference marker 220b. Paste
Position is bonded decided the combined Ri. Third light guide member 13
Reference numeral 1 denotes the side of the bonding surface with the half-wave plate 126, that is, the third surface 1
07c, the polarization separation film 124 and the third bonding reference marker 2
After forming 20c, the half-wave plate 126 is attached and the third joining reference marker 220c and the first joining reference marker 2 are attached .
The bonding position is determined by 20a and joined. Further, the focus error detecting element 121 and the reflection film 1 are formed on the fourth surface 107d.
18. The first set block is created by forming the cutting marker 221 and the fourth joining reference marker 220d.

FIG. 7B is a plan view of the first assembly block.
FIG. 7C shows a side view thereof.

Each element in the first set block is shown in FIG.
As shown in (b) and (c), a plurality are formed on the same plane.

A method of preparing a plurality of the first collective blocks and bonding them together to form a collective structure will be described.

FIG. 8A shows a fifth joining reference marker 22 formed on the fifth surface 107e of the first light guide member 105.
The fourth surface 107d of the other set blocks Ru bonded to the 0e
By the fourth joining reference marker 220d formed above
It is an exterior view showing a bonded Ruyosu.

These are pasted to n set blocks.
Aggregate structure as shown in FIG. 8 (b) in Rukoto combined can be formed.

The first polarizing beam splitter film 1 in FIG.
08, the angle of incidence of the central ray axis on θ, θ
Assuming that the direction inclined by θ with respect to 107b, 107c and 107d is X ′ and the X ′ axis and the Y ′ axis are as shown in FIG. 8, the plane including the X′-Y ′ plane is the light in FIG. Guide member 10
5, a block which is parallel to the first surface 105a or the second surface 105b and is determined by the length L, width W, and thickness d of the light guide member 105 in FIG. Many optical pickups can be aligned on the XY plane. That X'-Y 'by θ inclined with respect to plane the minimum configuration block 200 in Rukoto bonded by bonding the reference markers formed on each side a plurality of cluster block can be formed in a large number.

Therefore, the joined aggregate is represented by X′-Y ′
Plane block containing the smallest building blocks 200 large number of if cut out in a direction parallel to the plane can be cut out in the same shape. At the time of cutting, cutting is performed by the cutting marker 221 formed on the fourth surface 107d of the n-th set block forming the set component.

FIG. 9A is a plan view of a cut-out plane block. The cut-out flat block is mirror-finished so that the thickness of the flat block becomes the thickness d of the minimum constituent block 200. FIG. 9B is a side view of the mirror-finished plane block. Reference plane 20
The transmission diffraction grating 106 is formed on the surface 1a, and a first antireflection film 127a and a second antireflection film 127b are formed on the reference surface 201a and the other surface 201b, respectively.
FIG. 9C is a side view of a plane block on which the transmission diffraction grating 106 and the first and second antireflection films 127a and 127b are formed.

If the plane block is cut out in the X 'and Y' directions, the minimum configuration block 200 can be obtained. For the cutting positioning in the X ′ direction, the cutting position is determined based on the intersection line 230 between the first surface 201b and the first inclined surface 107a in FIG. 9A.

At the time of cutting in the Y 'direction, the position is determined by the cutting marker 221 formed on the fourth surface 107d of the n-th set block forming the set component, and cut is performed.

FIG. 10 shows the cut minimum configuration block 200 determined by the X ′ and Y ′ cutting positioning.

Hereinafter, a second embodiment of the present invention will be described with reference to the drawings. FIG. 14A is a front view of an optical pickup according to a second embodiment of the present invention, and FIG. 14B is a side view of the optical pickup according to the second embodiment of the present invention.

The optical pickup according to the second embodiment of the present invention comprises a substrate 301, a submount 302, a semiconductor laser chip 303, a prism 304, a light guide member 305 having a plurality of parallel inclined surfaces, a diffraction grating 306, an objective lens 309, 1st polarization beam splitter film 308, 2nd polarization beam splitter film 317, parallel light conversion element 32
5, 1/2 wavelength plate 326, polarization separation film 324, reflection film 3
18, a sensor substrate 316, a first light receiving sensor 370,
It comprises a second light receiving sensor 371 and the like, and is arranged in the same manner as in the first embodiment of the present invention.

In the second embodiment of the present invention, the method for detecting a magneto-optical signal guides the return light from the optical disk to the same path as in the first embodiment of the present invention, and converts the P-polarized light component into the same as in the first embodiment of the present invention. The first light-receiving sensor 370 receives the S-polarized light component by the second light-receiving sensor 371 and detects the difference between the first light-receiving sensor 370 and the second light-receiving sensor 371.

Next, a focus error signal detecting method and a tracking error signal detecting method according to the second embodiment of the present invention will be described. In the second embodiment of the present invention, the divided hologram 321 is formed as a focus error detecting element having a function as a focus detecting means. Optical disk board 3
The light reflected from the first polarization beam splitter film 308 and transmitted through the second polarization beam splitter film 317 among the return light beams from 10 is divided into at least two portions formed on the fourth inclined surface 307d of the light guide member 305. The light enters the hologram 321.

As shown in FIG. 12, the divided hologram 321 is a reflection hologram having regions 321a and 321b having at least two different patterns with a straight line intersecting the optical axis of incident light as a boundary.

One area 321 of divided hologram 321
The light incident on b is converted into diffracted light reaching the fourth light receiving sensor 376 divided into at least two parts, and the tracking error signal is detected by the three-beam method as in the first embodiment of the present invention.

The other area 3 of the divided hologram 321
The light incident on 21a is converted into diffracted light which forms an image on at least the dividing line of the third light receiving sensor 372 as shown in FIG.

If the outputs from the third light receiving sensors 372a and 372b are I372a and I372b, respectively, as can be seen from the circuit diagram of FIG.
E. FIG. ) Can be expressed by Equation 17 below.

(Equation 17) E. FIG. = I372a-I372b The distance between the disk and the objective lens, the spot shape on the third light receiving sensor 372, and the focus error signal will be described with reference to FIG.

FIG. 13A shows a spot shape on the third light receiving sensor 372 when the spot of the objective lens 309 is accurately focused on the information recording layer 311 of the optical disc 310. Since the spot on the third light receiving sensor 372 is on the dividing line and forms an image, the focus error signal is represented by the following equation (18).

(Equation 18) E. FIG. = 0 FIG. 13B shows an optical disc 310 and an objective lens 309.
9 shows a spot shape on the third light receiving sensor 372 when the distance between the third light receiving sensor 372 and the focusing distance is close. Since the diffracted light in the area 321a of the divided hologram 321 forms an image downstream of the third light receiving sensor 372, the spot on the third light receiving sensor 372 becomes semicircular and the third light receiving sensor 3
72 on 372a. Therefore, the focus error signal is represented by the following equation (19).

(Equation 19) E. FIG. > 0 FIG. 13C shows a spot shape on the third light receiving sensor 372 when the distance between the optical disc 310 and the objective lens 309 is far from the focused state. Since the diffracted light in the area 321a of the divided hologram 321 forms an image upstream of the third light receiving sensor, the spot on the third light receiving sensor 372 becomes semicircular and 372b of the third light receiving sensor 372
Come on. Therefore, the focus error signal is given by the following equation 2.
It becomes 0.

(Equation 20) E. FIG. <0> In the above method, the focus error signal is known as a knife edge method.

In the second embodiment of the present invention, the focus error signal is detected by the knife edge method by forming the return light from the disk disk on the split sensor by using the divided hologram 321. The return light may be designed so as to form an image upstream of the light receiving sensor with a divided hologram or a reflective film, and a knife edge may be provided at the image forming position to detect the light by the knife edge method.

In the second embodiment of the present invention, the divided hologram 321 is used as the focus error detecting element having the function as the focus detecting means.
Instead, an image may be formed using a lens or the like, and the focus error signal may be detected by the knife edge method.

The tracking error signal of the second embodiment of the present invention is detected by the three-beam method using the diffraction grating 306 and the side beam generated by the diffraction grating 306. Less without using 306
Both may be detected by the push-pull method by the fourth light receiving sensor 376 divided into two.

Hereinafter, a third embodiment of the present invention will be described with reference to the drawings. 11 (a) is a front view of the optical pickup in the third embodiment of the present invention, FIG. 11 (b) is a side view of a third embodiment of the present invention.

The optical pickup according to the third embodiment of the present invention comprises a substrate 401, a submount 402, a semiconductor laser chip 403, a prism 404, a light guide member 405 having a plurality of parallel inclined surfaces, a diffraction grating 406, an objective lens 409, First polarization beam splitter film 408, second polarization beam splitter film 417, parallel light conversion element 42
5, 1/2 wavelength plate 426, polarization separation film 424, reflection film 4
18, the sensor substrate 461 , the first light receiving sensor 470,
It comprises a second light receiving sensor 471 and the like, and is arranged in the same manner as in the first embodiment of the present invention.

In the third embodiment of the present invention, the magneto-optical signal guides the return light from the optical disk to the same path as that of the first embodiment of the present invention, and converts the P-polarized light component to the first light as in the first embodiment of the present invention.
The light receiving sensor 470 converts the S-polarized light component into the second light receiving sensor 4.
The light is received at 71 and detected by the differential between the first light receiving sensor 470 and the second light receiving sensor 471.

Next, a description will be given of a focus error signal detection method and a tracking error signal detection method according to a third embodiment of the present invention. In this embodiment, at least two focus error detecting elements having a function as focus detecting means are provided.
The divided hologram 421 was formed. Outgoing light from the optical disc 410 is reflected by the first polarizing beam splitter film 408 and is reflected by the second polarizing beam splitter film 4.
The light transmitted through the light guide member 17 is the fourth slope 40 of the light guide member 405.
The light enters the divided hologram 421 formed in 7d.

As shown in FIG. 15, the divided hologram 421 has regions 421a having at least two different patterns with a straight line intersecting the optical axis of incident light as a boundary.
421b is a reflection type hologram, and light incident on the divided hologram 421 is reflected by the divided hologram 421 .
As shown in FIG. 16 , the light is converted into two diffracted lights that form an image on the dividing line of the third light receiving sensor 472 divided into at least four.

The third light receiving sensor 472 472a, 47
2b, 472c, and 472d are output from I472
a, I472b, I472c, and I472d as shown in FIG.
As can be seen from the circuit diagram of FIG. 6, the focus error signal (FE) can be expressed by the following equation (21).

(Equation 21) E. FIG. = (I472a-I472b)-(I472c
-I472d) The distance between the disk board 410 and the objective lens 409, the spot shape on the third light receiving sensor 472, and the focus error signal will be described with reference to FIG.

FIG. 16A shows a spot shape on the third light receiving sensor 472 when the spot of the objective lens 409 is accurately focused on the information recording layer 411 of the optical disc 410. Since both spots on the third light receiving sensor 472 on the third light receiving sensor 472 of both the diffracted lights generated by the division hologram 421 are on the division line and form an image, the focus error signal is represented by Expression 22 below.

(Equation 22) E. FIG. = 0 FIG. 16B shows an optical disc 410 and an objective lens 409.
9 shows a spot shape on the third light receiving sensor 472 when the distance between the third light receiving sensor 472 and the focusing distance is close. Both diffracted lights of the division hologram 421 are transmitted to the third light receiving sensor 47.
The spots on the third light receiving sensor 472 are both semicircular in order to form an image downstream of the second light receiving sensor 472.
472a and 472d. Therefore, the focus error signal is represented by the following Expression 23.

(Equation 23) E. FIG. > 0 FIG. 16 (c) shows the optical disc 410 and the objective lens 409.
7 shows a spot shape on the third light receiving sensor 472 when the distance between the third light receiving sensor 472 and the focused state is far from the focused state. Both diffracted lights of the division hologram 421 are transmitted to the third light receiving sensor 472.
The spots on the third light receiving sensor 372 are both semicircular in order to form an image upstream of the third light receiving sensor 472.
It is above 72b and 472c. Therefore, the focus error signal is represented by the following equation (24).

(Equation 24) E. FIG. <0> In the above method, the focus error signal is known as the Foucault method.

In the third embodiment of the present invention, the focus error signal is detected by the Foucault method by forming the return light from the disk board 410 on the split sensor using the divided hologram 421. The return light may be designed so as to form an image upstream of the light receiving sensor with a divided hologram or a reflective film, and a prism may be provided at the image forming position to detect the light by the Foucault method.

In the third embodiment of the present invention, the divided hologram 421 is used as the focus error detecting element having the function as the focus detecting means.
Instead, an image may be formed using a lens or the like, and the focus error signal may be detected by the Foucault method.

In the third embodiment of the present invention, the tracking error signal is obtained by the three-beam method or the push-pull method as in the first embodiment of the present invention by using the return light from the optical disk 410 that has entered the divided hologram 421. To detect.

In the case of the three-beam method, the return light of the side beam generated by the diffraction grating 406 from the optical disk is received by the fourth light receiving sensor 476 divided into at least four by the divided hologram.

In the case of the push-pull method, the division line of the division hologram is taken in such a direction as to divide the return light from the optical disk in the track direction of the disk, so that the output of the third light receiving sensor 472 gives the following equation (25). A tracking error signal (TE) can be detected.

(Equation 25) E. FIG. = (I472a + I472b)-(I472c)
+ I472d) Hereinafter, a fourth embodiment of the present invention will be described with reference to the drawings. FIG. 17A is a front view of an optical pickup according to a fourth embodiment of the present invention, and FIG. 17B is a side view of the fourth embodiment of the present invention.

The laser light from the semiconductor laser chip 503 mounted on the substrate 501 via the submount 502 is applied to the prism 5 mounted on the substrate 501.
The light is reflected by the light and becomes diffused light. The diffused light is transmitted through the diffraction grating 506 formed on the second surface 505b of the light guide member 505.
Divides the beam into a main beam and two side beams.

The main beam and the side beams pass through the polarizing beam splitter film 508 formed on the first inclined surface 507a of the light guide member 505, exit from the first surface 505a of the light guide member 505, and exit the light guide member. 5
09 and the recording information surface 511 of the optical disc 510
Is imaged.

The return light from the optical disk 510 passes through the objective lens 509 and the first surface 505a of the light guide member 505, and then enters the polarization beam splitter film 508 again.

The reflected light from the polarization beam splitter film 508 out of the return light from the optical disc 510 is reflected on the second slope 507 parallel to the first slope 507 a of the light guide member 505.
b, is reflected by the reflection film 517 formed on the first slope 507b, is diffracted by the reflection type hologram 525 serving as a focus error detecting element formed on the first slope 507a of the light guide member 505, and is then laminated on the second slope 507b. The half-wave plate 526 is transmitted. The transmitted light has its polarization plane rotated by 45 °, and the S-polarized light component is reflected by the polarization separation film 524 formed on the third slope 507 c parallel to the first slope 507 a of the light guide member 505, and the sensor substrate 516 on the substrate 501. The main beam reaching the upper side is received by the second light receiving sensor 571, the side beam is received by the third light receiving sensor 576, the P-polarized light component is transmitted through the polarization separating film 524, and the first slope 5 of the light guide member 505 is formed.
The main beam is reflected by the reflective film 518 formed on the fourth inclined surface 507d parallel to the light receiving surface 507d, reaches the sensor substrate 516, the main beam is the first light receiving sensor 570, and the side beam is the third beam.
The light is received by the light receiving sensor 576.

The diffracted light of the reflection hologram 525 is designed so that a focal point exists between the polarization separation film 524 and the first light receiving sensor 570.

Next, each signal detection principle will be described with reference to FIG. Figure 18 is Ru Oh <br/> explanatory views of a sensor and signal processing circuit of the optical pickup according to the fourth embodiment of the present invention.

The first light receiving sensor 570 and the second light receiving sensor 571 are each a divided sensor divided into at least three, and the third light receiving sensor 576 is a divided sensor divided into at least two. First light receiving sensor 57
0, second light receiving sensor 571, third light receiving sensor 576
Each of the divided areas is divided into 57 areas as shown in FIG.
0a, 570b, 570c, 571a, 571b, 57
1c, 576a and 576b, and the output of each area is I5
70a, I570b, I570c, I571a, I57
1b, I571c, I576a, and I576b.

Since the RF reproduction signal (RF) receives the P-polarized light component and the S-polarized light component by the first light receiving sensor 570 and the second light receiving sensor 571, respectively, like the first embodiment of the present invention, Light receiving sensor 570 and second light receiving sensor 571
Is obtained by the following equation (26).

(Equation 26) F. = (I570a + I570b + I570c)-
(I571a + I571b + I571c) As in the first embodiment of the present invention, the tracking error signal (TE) is also such that each side beam is the third light receiving sensor 5 respectively.
Since the light is received by 576a and 576b of 76, as can be seen from the circuit diagram of FIG.

(Equation 27) E. FIG. = I576a-I576b In the fourth embodiment of the present invention, the tracking error signal is detected by the three-beam method, but may be detected by the push-pull method as in the first embodiment of the present invention. In the case of the push-pull method, the tracking error signal is obtained from the output of each area of the first light receiving sensor 570 and the second light receiving sensor 571 by the following Expression 28 as can be seen from the circuit diagram of FIG.

(Equation 28) E. FIG. = (I570a-I570c)-(I571a
-I571c) Next, the focus error signal (FE) will be described. F. E. FIG. Is obtained by the following equation 29 as can be seen from the circuit configuration of the circuit diagram of FIG.

(Equation 29) E. FIG. = [(I570a + I570c) -I570
b]-[(I571a + I571c) -I571b] Now, the spot of the objective lens 509 is accurately focused on the information recording layer 511 of the optical disc 510, and the first light receiving sensor 570 and the second light receiving sensor in this focused state The irradiation shape of the laser beam on
a, 515a, the irradiation intensity distribution of the laser beam, the positional relationship of the light receiving sensor, and the like are adjusted so as to obtain the following Expression 30.

(Equation 30) E. FIG. = 0 Next, when the distance between the optical disc 510 and the objective lens 509 is close from the in-focus state, the first light receiving sensor 5
70 and the second light receiving sensor 571 have laser beam irradiation shapes of 519b and 515b, respectively. E. FIG. Changes as in the following Expression 31.

(Equation 31) E. FIG. > 0 Conversely, when the distance between the optical disc 510 and the objective lens 509 is far from the in-focus state, the first light receiving sensor 57
The irradiation shape of the laser beam on the second light receiving sensor 571 is 519c and 515c. E. FIG. Changes as in the following Expression 32.

(Equation 32) E. FIG. <0 The above focus error detection method is known as a spot size method.

[0129] In the fourth embodiment of the present invention the anti-a focus error detecting element which functions as a focus detecting means
Although the projection hologram 525 was used, the reflection hologram 5 was used.
Instead of 25 , a focus error signal may be detected by a spot size method using a lens or the like.

Hereinafter, a fifth embodiment of the present invention will be described with reference to the drawings. FIG. 19A is a front view of an optical pickup according to a fifth embodiment of the present invention, and FIG. 19B is a side view of the fifth embodiment of the present invention.

The laser beam from the semiconductor laser chip 603 mounted on the substrate 601 via the submount 602 is applied to the prism 6 mounted on the substrate 601.
The light is reflected by the light and becomes diffused light. The diffused light is transmitted through the diffraction grating 606 formed on the second surface 605b of the light guide member 605.
Divides the beam into a main beam and two side beams.

The main beam and the side beam are divided into a first polarization beam splitter film 608a formed on the first slope 607a of the light guide member 605 and a second polarization beam splitter film formed on the second slope 607b parallel to the first slope. 608b and the first surface 605 of the light guide member 605.
The light guide member is emitted from a, is condensed by the objective lens 609, and forms an image on the recording information surface 611 of the optical disk 610.

The return light from the optical disk 610 passes through the objective lens 609 and the first surface 605a of the light guide member 605, and then returns to the second polarizing beam splitter film 608b.
Incident on.

The reflected light from the second polarization beam splitter film 608b of the return light from the optical disk 610 is reflected by the reflection film 617 formed on the third inclined surface 607c of the light guide member 605 parallel to the first inclined surface 607a. Then, the light is incident on a parallel light conversion element 625 such as a hologram or a lens formed on the second slope 607b of the light guide member 605, converted into parallel light, and then stacked on the third slope 607c.
The light passes through the wave plate 626. The transmitted light of the half-wave plate 626 rotates the polarization plane by 45 ° by the half-wave plate 626, and the fourth slope 6 parallel to the first slope 605a of the light guide member 605.
The S-polarized light component is reflected by the polarization splitting film 624 formed on the substrate 07d, reaches the sensor substrate 616 on the substrate 601 and is received by the second light receiving sensor 671, and the P-polarized light component is transmitted through the polarization splitting film 624, First of the guide member 605
The light is reflected by the reflective film 618 formed on the fifth slope 607e parallel to the slope 607a, reaches the sensor substrate 601 and is received by the first light receiving sensor 670.

Accordingly, since the P-polarized light component and the S-polarized light component of the magneto-optical signal (R.F.) are received by the first light receiving sensor 670 and the second light receiving sensor 671, respectively, the same as in the first embodiment of the present invention. First light receiving sensor 670 and second light receiving sensor 6
Since it is obtained by the differential of 71, it is detected by the following Expression 33.

(Equation 33) F. = I670-I671 On the other hand, of the return light from the optical disc 610, the transmitted light from the second polarizing beam splitter film 608b is incident again on the first polarizing beam splitter film 608a. The reflected light from the first polarization beam splitter film 608a is incident on a reflection film formed on the second inclined surface 607b, a focus error detection element 621 formed of a hologram, a lens, or the like, which functions as focus detection means, and thereafter, the substrate 601 is formed. The upper sensor substrate 616 is reached.

The focus error signal is detected by the astigmatism method, the knife edge method, or the Foucault method, as in the first embodiment, the second embodiment, and the third embodiment of the present invention.

Also, the tracking error signal is detected by the three-beam method using the side beam generated by the diffraction grating as in the first embodiment of the present invention, or by the push-pull method without using the diffraction grating.

Hereinafter, a sixth embodiment of the present invention will be described with reference to the drawings. FIG. 20A shows a sixth embodiment of the present invention .
Top view of an optical pickup in 施例, FIG. 20 (b) front view of the present invention the sixth embodiment, FIG. 20 (c) is a side view of the present invention the sixth embodiment.

The laser light from the semiconductor laser chip 703 mounted on the substrate 701 via the submount 702 is applied to the prism 7 mounted on the substrate 701.
The light is reflected by the light and becomes diffused light. The diffused light passes through the diffraction grating 706 formed on the second surface 705b of the light guide member 705.
Divides the beam into a main beam and two side beams.

The main beam and the side beams pass through the polarizing beam splitter film 708 formed on the first inclined surface 707a of the light guide member 705, exit the light guide member from the first surface 705a of the light guide member 705, and exit the objective lens. 7
09 and the information recording surface 711 of the optical disc 710
Is imaged.

The return light from the optical disk 710 passes through the objective lens 709 and the first surface 705a of the light guide member 705, and then enters the polarization beam splitter film 708 again.

The reflected light from the polarization beam splitter film 708 out of the return light from the optical disk 710 is reflected on the second inclined surface 707 parallel to the first inclined surface 707 a of the light guide member 705.
b is incident on the hologram 721 formed on b and is converted into backward-path diffracted light.

At this time, the return path diffracted light is diffracted in the direction of (2n + 1) π / 4 with respect to the polarization direction of the light from the semiconductor laser chip 703 when n is an integer, and The P-polarized light component is transmitted by the polarization separation film 724 formed on the slope 707a, reaches the sensor substrate 716 on the substrate 701, the main beam is received by the first light receiving sensor 770, and the side beam is received by the third light receiving sensor 776. The polarized light component is reflected by the polarized light separating film 724, reflected by the reflecting film 718 formed on the second inclined surface 707b of the light guide member 705, reaches the sensor substrate 716, the main beam is the second light receiving sensor 771, and the side beam is the third light. The light is received by the light receiving sensor 776.

When the diffraction direction of the diffracted light converted by the hologram 721 is n as an integer, the polarization direction of the light from the semiconductor laser chip 703 is (2n + 1) π
Since the light is set to the direction of / 4, the light incident on the polarization separation film 724 has about half the P-polarized component and the S-polarized component with respect to the polarization separation film 724, and the transmitted light and the reflected light from the polarization separation film 724. The light quantity of each light becomes about half of the diffracted light.

The diffracted light of the hologram 721 is designed so that a focal point exists between the polarization separation film 724 and the second light receiving sensor 771.

Next, the principle of detecting each signal will be described with reference to FIG. FIG. 21 is an explanatory diagram of a sensor and a signal processing circuit of an optical pickup according to a sixth embodiment of the present invention.

The first light receiving sensor 770 and the second light receiving sensor 771 are each a divided sensor divided into at least three, and the third light receiving sensor is a divided sensor divided into at least two. The divided areas of the first light receiving sensor 770, the second light receiving sensor 771, and the third light receiving sensor 776 are respectively denoted by 770a and 770a as shown in FIG.
770b, 770c, 771a, 771b, 771c,
776a and 776b and the output of each area is I770
a, I770b, I770c, I771a, I771
b, I771c, I776a, and I776b.

The magneto-optical signal (RF) has a P-polarized light component and S
Since the polarized light components are received by the first light receiving sensor 770 and the second light receiving sensor 771, respectively, they are obtained by the differential between the first light receiving sensor 770 and the second light receiving sensor 771 as in the first embodiment of the present invention.

The principle of detecting a magneto-optical signal will be described in more detail with reference to FIGS. In FIG. 22, an arrow 750 indicates the polarization direction of the linearly polarized light before being incident on the information recording surface 711 of the optical disk 710 in FIG. Optical disk board 71
If information is recorded on the 0 information recording surface 711, the polarization state of the reflected light from the optical disc 710 is linearly polarized light 75.
The state is 1 or linearly polarized light 752. When the reflected light from the optical disc 710 in this state enters the polarization beam splitter film 708 formed on the first slope 707a of the light guide member 705, the polarization beam splitter film 70
The polarization state of the reflected light reflected at 8 becomes linear polarization 753 or linear polarization 754, and the apparent Kerr rotation angle increases. Further, when n is an integer in the hologram, the light is diffracted in the direction of (2n + 1) π / 4 with respect to the polarization direction of the light from the semiconductor laser chip 703, so that the polarization separation film is used.
The polarization state of the light incident on 724 is such that the polarization direction in FIG. 22 is rotated by 45 ° as shown in FIG. The P-polarized light component received by the first light receiving sensor 770 is the signal 7 in FIG.
The S-polarized light component received by the second light receiving sensor 771 as shown at 61 is as shown by a signal 762 in FIG. Both signals 761
Since the phase of the signal 762 is shifted by 180 °, the signal component is doubled by the differential amplification, and an RF signal in which the noise of the same phase component is canceled can be obtained.

Accordingly, the RF signal (RF) is detected by the following equation (34). (Equation 34) F. = (I770a + I770b + I770c)-
(I771a + I771b + I771c) As for the tracking error signal (TE), both side beams generated by the diffraction grating 706 are received by the 776a and 776b of the third light receiving sensor 776, respectively, as in the first embodiment of the present invention. As can be seen from the circuit diagram of FIG.

(Equation 35) E. FIG. = I776a-I776b In the sixth embodiment of the present invention, the tracking error signal is detected by the three-beam method, but may be detected by the push-pull method as in the first embodiment of the present invention. In the case of the push-pull method, the tracking error signal is obtained from the output of each area of the first light receiving sensor 770 and the second light receiving sensor 771 according to the following Expression 36 as can be seen from the circuit diagram of FIG.

(Equation 36) E. FIG. = (I770a-I770c)-(I771a
-I771c) Next, the focus error signal (FE) will be described. F. E. FIG. Is obtained by the following Expression 37 as can be seen from the circuit configuration of the circuit diagram of FIG.

(Equation 37) E. FIG. =-[(I770a + I770c) -I770
b] + [(I771a + I771c) −I771b] Now, the spot 713 of the objective lens 709 is accurately focused on the information recording surface 711 of the optical disc 710, and the first light receiving sensor 770 and the second
Assuming that the irradiation shape of the laser light on the light receiving sensor 771 is 719a and 715a, respectively, the irradiation intensity distribution of the laser light and the positional relationship of the light receiving sensor are adjusted so as to obtain the following Expression 38.

(Equation 38) E. FIG. = 0 Next, when the distance between the optical disk 710 and the objective lens 709 is close from the in-focus state, the first light receiving sensor 7
70 and the second light receiving sensor 771 have the irradiation shapes of the laser beams 719b and 715b, respectively. E. FIG. Changes as in the following Expression 39.

(Equation 39) E. FIG. > 0 Conversely, when the distance between the optical disc 710 and the objective lens 709 is far from the focused state, the first light receiving sensor 77
The irradiation shapes of the laser light on the light receiving sensor 771 and the second light receiving sensor 771 are 719c and 715c. E. FIG. Changes as in the following Expression 40.

(Equation 40) E. FIG. <0 The above focus error detection method is known as a spot size method.

In the sixth embodiment of the present invention, the hologram 7
Although 21 is used, a focus error signal may be detected by a spot size method using a lens or the like instead of the hologram 721.

Hereinafter, a seventh embodiment of the present invention will be described with reference to the drawings. 24A is a top view of an optical pickup according to a seventh embodiment of the present invention, FIG. 24B is a front view of the seventh embodiment of the present invention, and FIG. 24C is a seventh embodiment of the present invention. FIG.

The laser light from the semiconductor laser chip 803 mounted on the substrate 801 via the submount 802 is applied to the prism 8 mounted on the substrate 801.
The light is reflected by the light and becomes diffused light. The diffused light is transmitted through the diffraction grating 806 formed on the second surface 805b of the light guide member 805.
Divides the beam into a main beam and two side beams.

The main beam and the side beams pass through the first polarizing beam splitter film 808 formed on the first slope 807 a of the light guide member 805, and
The light guide member is emitted from the first surface 805 a of the optical disk 810, and condensed by the objective lens 809.
Image 11 is formed.

The return light from the optical disk 810 passes through the objective lens 809 and the first surface 805a of the light guide member 805, and then enters the first polarization beam splitter film 808 again.

The reflected light from the first polarization beam splitter film 808 of the return light from the optical disc 810 is reflected on the second slope 8 parallel to the first slope 807 a of the light guide member 805.
07b formed on the second polarizing beam splitter 81
7 is incident.

The light reflected from the second polarizing beam splitter 817 will be described. The reflected light from the second polarization beam splitter 817 is reflected on the first slope 8 of the light guide member 805.
The light enters the hologram 825 formed on the optical path 07a and is converted into the backward-path diffracted light.

At this time, the return-path diffracted light is diffracted in the direction of (2n + 1) π / 4 with respect to the polarization direction of the light from the semiconductor laser chip 803 when n is an integer. Polarization separation film 8 formed with slope 807b
The S-polarized light component is reflected by 24, reaches the sensor substrate 816 on the substrate 801, the main beam is received by the second light-receiving sensor 871, the side beam is received by the third light-receiving sensor 876, and the P-polarized light component passes through the polarization splitting film 824. And a third slope 8 parallel to the first slope 807a of the light guide member 805.
Sen is reflected by the reflection film 818 formed on 07c
The main beam reaching the substrate 816 is received by the first light receiving sensor 871 and the side beam is received by the third light receiving sensor 876.

When the diffraction direction of the diffracted light converted by the hologram 825 is n as an integer, the polarization direction of the light from the semiconductor laser chip 803 is (2n + 1) π /
4, the light incident on the polarization splitting film 824 has about half the P-polarized component and the S-polarized component for the polarized light splitting film 824, and the transmitted light and the reflected light from the polarization splitting film 824. Are about half of the diffracted light.

The magneto-optical signal (RF) is detected by the first light receiving sensor 870 and the second light receiving sensor 870 according to the same detection principle as in the sixth embodiment of the present invention.
Since it is obtained by the differential of the light receiving sensor 871, if the output I870 of the first light receiving sensor 870 and the output of the second light receiving sensor 871 are I871, it is detected by the following equation 41.

(Equation 41) F. = I870-I871 Next, the transmitted light of the second polarizing beam splitter 817 will be described.

The transmitted light of the second polarization beam splitter 817 is incident on a focus error detection element 821 formed on the third inclined surface 807c of the light guide member 805 and having a function as focus detection means.

The main beam of the light incident on the focus error detecting element 821 is converted into light for focus detection and received by the third light receiving sensor 872 divided into at least two. The focus error detecting element 821 is the first embodiment of the present invention,
Similarly to the second and third embodiments, any of a hologram or a lens for astigmatism, knife edge method or Foucault method may be used, and the focus error signal is obtained by the output of the third light receiving sensor. It is detected by the knife edge method or Foucault method.

The inner side beam of the light that has entered the focus error detecting element 821 is received by at least the fourth light receiving sensor 876, and the tracking error signal is received by the fourth light receiving sensor in the same manner as in the first embodiment of the present invention. The output of the sensor 876 is detected by a three-beam method.

In the seventh embodiment of the present invention, the tracking error signal is detected by the three-beam method using the diffraction grating, but may be detected by the push-pull method as in the first embodiment of the present invention.

Hereinafter, an eighth embodiment of the present invention will be described. FIG. 25A shows the first and second light guide members 901 and 9.
03 is a side view before the Ru bonded.

The first surface 901a of the first light guide member 901
A first joining reference marker 907a on the surface, and a beam splitter film 90 on a second surface 901b of the light guide member 901.
5 and a second joining reference marker 907b, a third joining reference marker 907c on the first surface 903a of the second light guide member, and a focus detection error detecting element 906 on the second surface of the second light guide member 903. 4 junction reference marker 907d
Is formed, and the second joining reference marker 907b and the second
3 to obtain a bonding surface 902 determines the bonding position by joining the fiducial markers 907c, to form a first set block.
Similarly, an n number of aggregate blocks are formed, and the first joint reference marker 907a and the fourth aggregate block
The assembly blocks are joined by the joining reference marker to obtain a joining surface 904, and an assembly component is formed. As in the first embodiment,
After forming the first collective block and its collective component, a planar block was formed and formed into the minimum component block 900.

FIG. 25B is a side view of a collective structure in which the minimum configuration block 900 produced by the manufacturing method of Embodiment 1 is used as a read-only optical pickup, and FIG. It is a side view of a pickup.

[0176]

According to the present invention, a light emitting element, an image forming means for forming an image of light from the light emitting element on a disk, a beam splitter film having polarization selectivity, an analyzer having a polarization separation function, and an analyzer are provided. An analyzer that converts the polarization state of the incident light into linearly polarized light of about 45 °, an incident light polarization conversion element, a focus error detection element having a function as focus detection means, and emits linearly polarized light installed on the sensor substrate. A light-receiving element including a light-emitting element and a plurality of light-receiving sensors, and the separated disk after separating return light from the disk disk that has passed through the imaging unit with light from the light-emitting element by the polarizing beam splitter film. The return light from the board is incident on the focus error detection element and the analyzer incident light polarization conversion element. The light that has passed through the analyzer incident light polarization conversion element is made incident on the analyzer and separated into P-polarized light and S-polarized light, and then the light of each component is received by a light-receiving sensor.
Detect signal. On the other hand, the light incident on the focus error detecting element is converted into light for focus detection and is received by a light receiving sensor, so that the polarization of the return light from the disk board which enters the polarization separating means by the action of the analyzer incident light polarization converting element. The state is linear polarized light of about 45 °, and the P-polarized light component and the S-polarized light component become light of about 50% each. In addition, the in-phase noise components other than the magneto-optical signal are removed, and the light-receiving sensor for detecting the RF signal detects only the RF signal. By increasing the apparent Kerr rotation angle by using a polarization-selective beam splitter film to separate the light from the disk and the return light from the disk. C / N high ratio R
An F reproduction signal can be obtained. In addition, to separate the P-polarized component and the S-polarized component into the focus error detecting element having the function as the focus detecting means, to guide the return light from the disk to the return light from the disk, and to detect the focus error signal. Even if the light amount ratio between the P-polarized light and the S-polarized light of the return light from the optical head changes, no offset occurs in the focus error signal. Also, when a tracking error signal is detected by the three-beam method, the spot size on the sensor can be reduced, and the occurrence of crosstalk between the main beam and the side beam can be suppressed.

A structure having an optical thin film provided on a substrate is formed, a plurality of the structures are prepared, and the optical thin films are bonded so as to be sandwiched between bases to form a collective structure. By cutting at an angle to the joining surface, the number of steps can be reduced and the productivity can be improved.

[Brief description of the drawings]

FIG. 1 is a diagram showing an optical pickup according to a first embodiment of the present invention.

FIG. 2 is a first explanatory diagram of an enhancement effect of the optical pickup according to the first embodiment of the present invention.

FIG. 3 is a first explanatory view of a principle of detecting a magneto-optical signal of the optical pickup according to the first embodiment of the present invention;

FIG. 4 is an explanatory diagram of a light receiving sensor shape and a signal processing circuit of the optical pickup according to the first embodiment of the present invention.

FIG. 5 is a diagram illustrating the principle of detecting a focus error signal by an astigmatism method of the optical pickup according to the first embodiment of the present invention.

FIG. 6 is a diagram showing a method for manufacturing an optical pickup according to one embodiment of the present invention.

FIG. 7 is a diagram showing a method of manufacturing an optical pickup according to one embodiment of the present invention.

FIG. 8 is a diagram showing a method of manufacturing an optical pickup according to one embodiment of the present invention.

FIG. 9 is a diagram showing a method of manufacturing an optical pickup according to one embodiment of the present invention.

FIG. 10 is a diagram showing a method of manufacturing an optical pickup according to one embodiment of the present invention.

FIG. 11 is a diagram showing an optical pickup according to a third embodiment of the present invention.

FIG. 12 is an explanatory diagram of a hologram as a focus error detecting element of an optical pickup according to a second embodiment of the present invention.

FIG. 13 is a diagram illustrating the principle of detecting a focus error signal by a knife edge method of an optical pickup according to a second embodiment of the present invention.

FIG. 14 illustrates an optical pickup according to a second embodiment of the present invention.

FIG. 15 is an explanatory diagram of a hologram pattern as a focus error detecting element of an optical pickup according to a third embodiment of the present invention.

FIG. 16 is a diagram illustrating the principle of detecting a focus error signal by the Foucault method of an optical pickup according to a third embodiment of the present invention.

FIG. 17 is a diagram showing an optical pickup according to a fourth embodiment of the present invention.

FIG. 18 is an explanatory diagram of a sensor and a signal processing circuit of an optical pickup according to a fourth embodiment of the present invention.

FIG. 19 is a diagram showing an optical pickup according to a fifth embodiment of the present invention.

FIG. 20 is a diagram showing an optical pickup according to a sixth embodiment of the present invention.

FIG. 21 is an explanatory diagram of a light-receiving sensor shape and a signal processing circuit of an optical pickup according to a sixth embodiment of the present invention.

FIG. 22 is a second explanatory diagram of the enhancement effect of the optical pickup according to the sixth embodiment of the present invention.

FIG. 23 is a second explanatory view of the principle of detecting a magneto-optical signal of the optical pickup according to the sixth embodiment of the present invention.

FIG. 24 is a diagram showing an optical pickup according to a seventh embodiment of the present invention.

FIG. 25 is an illustration of a manufacturing method according to an eighth embodiment of the present invention.

FIG. 26 is a diagram showing a conventional optical pickup.

FIG. 27 is an explanatory diagram of a hologram pattern of a conventional optical pickup.

FIG. 28 is a diagram showing a principle of detecting a magneto-optical signal of a conventional optical pickup.

FIG. 29 is an explanatory diagram of a light receiving sensor shape and a signal processing circuit of a conventional optical pickup.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Sensor board | substrate 2 Semiconductor laser chip 4 Reflection prism 5 Optical guide member 6 Incident window 8 Hologram 10 Objective lens 11 Optical disk board 18 1st return polarization separation part 19 2nd return polarization separation part 26 1st light receiving sensor 27 2nd light receiving sensor 30 First return path reflection section 31 Second return path reflection section 34 First transmission window 35 Second transmission window 38 Third light receiving sensor 39 Fourth light receiving sensor 44 Lead frame 101 Substrate 102 Submount 103 Semiconductor laser chip 104 Reflecting prism 105 Light guide member 106 Diffraction Grating 108 First Polarization Beam Splitter Film 109 Objective Lens 110 Optical Disk Board 116 Sensor Substrate 117 Second Polarization Beam Splitter Film 118 Reflection Film 121 Focus Error Detection Element 124 Polarization Separation Film 125 Parallel Light Conversion Element 126 1 / Wave plate 130 Second light guide member 131 Third light guide member 170 First light receiving sensor 171 Second light receiving sensor 172 Third light receiving sensor 176 Fourth light receiving sensor 180 Information track 200 Minimum configuration block 201a Plane block reference surface 201b The other of 201a Surface 220a first joining reference marker 220b second joining reference marker 220c third joining reference marker 220d fourth joining reference marker 222 cutting marker 230 intersection line of the first surface of 105 and plane block reference surface 301 substrate 302 submount 303 semiconductor Laser chip 304 Reflecting prism 305 Optical guide member 306 Diffraction grating 308 First polarization beam splitter film 309 Objective lens 310 Optical disc 316 Sensor substrate 317 Second polarization beam splitter Target film 318 Reflection film 321 Split hologram 324 Polarization separation film 325 Parallel light conversion element 326 1/2 wavelength plate 370 First light receiving sensor 371 Second light receiving sensor 372 Third light receiving sensor 376 Fourth light receiving sensor 401 Substrate 402 Submount 403 Semiconductor Laser chip 404 Reflecting prism 405 Light guide member 406 Diffraction grating 408 First polarizing beam splitter film 409 Objective lens 410 Optical disc board 416 Sensor substrate 417 Second polarizing beam splitter film 418 Reflecting film 421 Split hologram 424 Polarization separating film 425 Parallel light conversion element 426 1/2 wavelength plate 470 First light receiving sensor 471 Second light receiving sensor 472 Third light receiving sensor 476 Fourth light receiving sensor 501 Substrate 502 Submount 503 Semiconductor laser Top 504 Reflection prism 505 Light guide member 506 Diffraction grating 508 Polarization beam splitter film 509 Objective lens 510 Optical disk board 516 Sensor substrate 517 Reflection film 518 Reflection film 521 Hologram 524 Polarization separation film 526 1/2 wavelength plate 570 First light receiving sensor 571 Second light receiving sensor 576 Third light receiving sensor 601 Substrate 602 Submount 603 Semiconductor laser chip 604 Reflecting prism 605 Light guide member 606 Diffraction grating 608a First polarization beam splitter film 608b Second polarization beam splitter film 609 Objective lens 610 Optical disk disk 616 Sensor Substrate 617 Reflecting film 618 Reflecting film 621 Focus error detecting element 624 Polarization separating film 670 First light receiving sensor 671 Second light receiving sensor 672 Third light receiving Sensor 676 Fourth light receiving sensor 701 Substrate 702 Submount 703 Semiconductor laser chip 704 Reflecting prism 705 Light guide member 706 Diffraction grating 708 Polarization beam splitter film 709 Objective lens 710 Optical disk 716 Sensor substrate 718 Reflection film 721 Hologram 724 Polarization separation film 770 First 1 light receiving sensor 771 second light receiving sensor 776 third light receiving sensor 801 substrate 802 submount 803 semiconductor laser chip 804 reflecting prism 805 light guide member 806 diffraction grating 808 first polarization beam splitter film 809 objective lens 810 optical disk 816 sensor substrate 817 Two-polarization beam splitter film 818 Reflection film 821 Focus error detection element 824 Polarization separation film 825 Hologram 870 First Light sensor 871 Second light receiving sensor 872 Third light receiving sensor 876 Fourth receiving sensor 900 Minimum configuration block 901 First light guide member 901a First surface of first light guide member 901b Second surface of first light guide member 902 First Joint surface 903 Second light guide member 903a First surface of second light guide member 903b Second surface of second light guide member 904 Second joint surface 905 Beam splitter 906 Focus error detecting element 907a First joint reference marker 907b Second Joining standard marker 907c Third joining standard marker 907d Fourth joining standard marker

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁷ Identification code FI G11B 11/105 551 G11B 11/105 551N 551S (72) Inventor Kazuhiko Higo 1006 Odakadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd. (72) Inventor Toshihiro Koga 1006 Kadoma, Kadoma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. (72) Inventor Shinobu Uesuru 1006, Kadoma, Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd. (56) References JP-A-3-102647 (JP, A) JP-A-4-289541 (JP, A) JP-A-5-314569 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) ) G11B 7/135 G11B 7/22 G11B 11/105

Claims (39)

(57) [Claims] 1. A light emitting element, a light receiving element, a light condensing means for condensing light on an information recording surface of an optical disc, and an optical functional element
A light guide member formed by stacking
An optical pickup having the light guide member, the polarization selectivity of certain beam splitter (hereinafter polarization beam splitter), an analyzer having a polarization separating function, the polarization state of the incident light to the analyzer about and a analyzer incident light polarization conversion element for converting the 45 ° linearly polarized light, guides the condensing means light from the light emitting element is transmitted through the polarization beam splitter,
After reflecting the light from the condensing unit with the polarization beam splitter and guiding the light to the analyzer incident light polarization conversion element,
And configured to direct to the analyzer, substantially parallel to form the said polarization beam splitter and said analyzer incident light polarization conversion element
The optical pick-up which is characterized in that form. 2. The optical pickup according to claim 1, wherein an optical rotation element is used as the analyzer incident light polarization conversion element. 3. The optical pickup according to claim 2, wherein a half-wave plate is used as the optical rotation element. 4. The optical pickup according to claim 1, wherein a hologram is used as the analyzer incident light polarization conversion element. 5. The optical pickup according to claim 4, wherein said hologram is of a reflection type. 6. The optical pickup according to claim 1, wherein a lens is used as the analyzer incident light polarization conversion element. 7. The optical pickup according to claim 6, wherein said lens is of a reflection type. 8. The optical pickup according to claim 1, wherein a polarization separation film is used as said analyzer. 9. The optical pickup according to claim 2, wherein the light from the polarization beam splitter is converted into parallel light by a parallel light conversion element, and then the light is incident on the optical rotator. 10. The optical pickup according to claim 9, wherein the parallel light conversion element and the polarization separation film are substantially parallel to the polarization beam splitter. 11. The optical pickup according to claim 1, wherein the light from the polarization beam splitter is guided to a light receiving sensor by a focus error detecting element arranged in parallel with the polarization beam splitter. 12. The optical pickup according to claim 11, wherein a hologram is used as the focus error detection element, and a focus error signal is detected by an astigmatism method. 13. The optical pickup according to claim 12, wherein the hologram used as said focus error detecting element is of a reflection type. 14. An optical pickup according to claim 11, wherein a lens is used as said focus error detecting element, and a focus error signal is detected by an astigmatism method. 15. The optical pickup according to claim 14, wherein the lens used as said focus error detecting element is of a reflection type. 16. An optical pickup according to claim 11, wherein a hologram is used as said focus error detecting element, and a focus error signal is detected by a knife edge method. 17. The optical pickup according to claim 16, wherein the hologram used as the focus error detecting element is of a reflection type. 18. The optical pickup according to claim 11, wherein a lens is used as a focus error detecting element, and a focus error signal is detected by a knife edge method. 19. The optical pickup according to claim 18, wherein the lens used as said focus error detecting element is of a reflection type. 20. At least two focus error detecting elements
12. The optical pickup according to claim 11, wherein a focus error signal is detected by a Foucault method using a hologram having regions having two different patterns. 21. The optical pickup according to claim 20, wherein the hologram used as the focus error detecting element is a reflection type. 22. The optical pickup according to claim 11, wherein a lens is used as a focus error detecting element, and a focus error signal is detected by a Foucault method. 23. The optical pickup according to claim 22, wherein a lens used as said focus error detecting element is of a reflection type. 24. A lens as a focus error detecting element having two lenses
14. The method according to claim 14, wherein the P method is used.
24. The optical pickup according to any one of 8, 19, 22 and 23. 25. The optical pickup according to claim 1, further comprising a diffraction grating, wherein a tracking error signal is detected by a three-beam method. 26. The optical pickup according to claim 1, wherein a tracking error signal is detected by a push-pull method. 27. The light guide member has a polarization selectivity.
Beam splitter and analyzer with polarization separation function
And the polarization state of the light incident on the analyzer as a straight line of about 45 °.
And a analyzer incident light polarization conversion element for converting the polarization, the backward light from the focusing means is the polarization beam splitter
And the analyzer to the incident light polarization conversion element and the analyzer.
Before the car rotation angle is apparently increased
2. The light receiving element according to claim 1, wherein the light is received by the light receiving element.
Optical pickup. 28. The light guide member comprises at least two light guide members.
Polarization-selective beam splitter
And an analyzer having a polarization separation function, and an input to the analyzer.
An analyzer that converts the polarization state of emitted light into linearly polarized light of about 45 °
An incident light polarization conversion element, and the return light from the light condensing means is a polarization beam splitter.
The analyzer at least two times and the analyzer incident light polarization conversion element
To the analyzer and the Kerr rotation angle.
It is characterized by receiving light by the light receiving element after increasing the height
The optical pickup according to claim 1, wherein 29. An optical thin film and a reference marker on a plurality of substrates
Forming a chromatography to form a junction block formed by joining another substrate onto the optical thin film, switching the junction block inclined surface against <br/> the bonding surface a plane including the reference marker <br/> A method for manufacturing an optical element, comprising: 30. An optical thin film and a reference marker on a plurality of substrates
To form the over laminating transparent members to form a further junction block formed by joining another substrate onto the optical thin film, the reference
A surface including a marker, which is inclined with respect to the bonding surface
A method of manufacturing an optical element , comprising cutting the joining block at a surface . 31. The reference marker is provided on one side of the substrate.
29. The method according to claim 29, wherein the surface is formed on a surface.
30. The method for manufacturing an optical element according to item 30, wherein 32. The fiducial marker is in contact with the optical thin film.
Formed on the same side surface and on the bonding surface side of the other substrate
31. The device according to claim 29, wherein the device is formed.
A method for producing the optical element described in the above. 33. A beam splitter film having a first polarization selectivity and a parallel light conversion element are separately formed on a substrate, a first transparent member is laminated on the substrate, and a second transparent member is formed on the transparent member. Forming a polarization-selective beam splitter film, laminating an optical rotator on the first transparent member, forming a polarization separation film on the optical rotator, and forming a second transparent member on the optical rotator. Laminated, a focus error detecting element and a reflection film are formed on the second transparent member, and a bonding block in which another substrate is bonded on the second transparent member is formed. A method for manufacturing an optical pickup, characterized in that the optical pickup is cut at an angle. 34. The optical thin film and the reference marker structure is formed which is provided on a substrate, the structure is more prepared, wherein the optical thin film and the reference marker as sandwiched between the substrates together reference marker And forming a collective structure by joining them together, and cutting the collective structure so as to be inclined with respect to the joining surface. 35. The method for manufacturing an optical element according to claim 34, wherein the components having the same length in the longitudinal direction perpendicular to the laminating direction are used. 36. The method of manufacturing an optical element according to claim 34, wherein the assembly is formed so that end faces of the components are not aligned on the same plane to form the aggregate component. 37. The reference marker is provided on one side of the substrate.
Claim that it has formed on the surface of claim 34, feature 3
7. The method for producing an optical element according to item 6. 38. The fiducial marker comprises: an optical thin film;
Formed on the same side surface and on the bonding surface side of the other substrate
37. The device according to claim 34, wherein the device is formed.
Manufacturing method of the above-mentioned optical element. 39. A first beam splitter film is formed on a substrate, a first transparent member is laminated on the substrate, a focus detection element and a reflection film are formed on the transparent member, A method for manufacturing an optical pickup, comprising: forming a bonding block in which another substrate is bonded on a transparent member; and cutting the bonding block at an angle to the bonding surface.