JPH1074331A - Reflective type photoelectric sensor and optical disk discriminating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve focus detecting accuracy and to shorten the detecting time by detecting the face wobbling and inclination of an optical disk, and simultaneously and discriminating the type of the optical disk by one reflective type photoelectric sensor. SOLUTION: A light-emitting element 1, with which a light beam B is projected on the outer peripheral surface of the rotating optical disk A, and a position- detecting element (two-dimensional PSD) 2, with which it is possible to execute the two-dimensional position-detection as a light-receiving element for receiving a reflected light spot of the light beam B reflected on the outer peripheral surface, are provided within the main body. Further, the quantity of face wobbling and the quantity of inclination of the optical disk A are obtained in accordance with the detection signal of the two-dimensional PSD 2 by the same reflected light spot by a signal processing circuit 30 for processing a detection signal of the two-dimensional PSD 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates generally to a reflection type photoelectric sensor for projecting light to a detection object and receiving the reflected light, and more particularly, to a reflection type photoelectric sensor which is built in an optical disk apparatus and has a light on an outer peripheral surface of the optical disk. The present invention relates to a reflection type photoelectric sensor that detects a shake of an optical disk by irradiating a beam. Light D
The present invention relates to an optical disc discriminating apparatus for discriminating the type of an optical disc such as a VD, a CD, and a PD.

[0002]

2. Description of the Related Art As shown in FIG. 7, a conventional reflection type photoelectric sensor comprises a light emitting element 50 as a light emitting source and a light receiving element 51 for receiving the reflected light, and a light beam 52 from the light emitting element 50. Is projected on an optical disk 53, the reflected light 54 is received by a light receiving element 51, and the fluctuation of the optical disk 53 is detected by a change in the amount of received light.

FIG. 8A shows a conventional reflection type photoelectric sensor 5.
FIG. 8B is a vertical cross-sectional view showing an example of FIG. 5, and FIG. The reflection type photoelectric sensor 55 is
6, a light receiving element 57 and a light emitting element 58 are provided,
The light beam 59 from the light emitting element 58 is condensed by a condensing lens 60 provided on the upper surface of the main body 56 and the optical disk 53
, And the reflected light 61 reflected by the optical disk 53 is condensed again by the condenser lens 60 to form an image on the light receiving element 57. In the figure, 62 and 63 are electrodes for supplying power to the light emitting element, and 64 is an output terminal for extracting a detection signal of the light receiving element. Further, the light emitting element 58
The light-receiving element 57 and the light-emitting element 58 are shielded by a light-shielding plate 65 so that the light beam 59 is not directly received in the main body 56. Thus, in the reflection-type photoelectric sensor 55, when the optical disk 53 is tilted, the amount of light incident on the light receiving element 57 changes, so that the tilt of the optical disk 53 is detected.

The optical disk 53 is driven to rotate about the center of the disk by the optical disk device, and the outer edge of the disk may be shaken during rotation, so that accurate reading may not be performed during pickup. FIG.
FIG. 9A is a diagram showing a state in which the optical disk 53 is inclined with respect to the rotation plane. As shown in FIG. 9B, the vertical swinging of the optical disk 53 is called surface wobble. .

However, since both the surface deflection and the inclination are detected by a decrease in the amount of light received by a single light receiving element, the reflection type photoelectric sensor shown in FIG. Even if they were present, they could not be detected separately. In discriminating an optical disk, C
D or LD could not be distinguished from DVD.

FIG. 10 is a view showing a reflection type photoelectric sensor for detecting surface deflection of an optical disk. In this reflection type photoelectric sensor, a light projecting section 72a for irradiating a slit-like light beam 72 long in the X-axis direction and , A one-dimensional position detecting element (one-dimensional PSD) 70 having a position detecting direction in the Y-axis direction is arranged. With such an arrangement, the optical disk 5
When 3 moves up and down, the slit-like reflected light 71 moves back and forth in the Y-axis direction. Accordingly, the reflected light beam 73 moves in the Y-axis direction in accordance with the surface deflection of the optical disk 53, and the surface deflection of the optical disk 53 can be detected based on where the reflected light 71 is detected.
Then, even if the tilt occurs, the position of the reflected light 71 in the Y-axis direction does not change, so that only the surface shake can be detected without being affected by the tilt.

FIG. 11 is a view showing a reflection type photoelectric sensor for detecting the inclination of the optical disk 53. In this reflection type photoelectric sensor, a light projecting section 82a for irradiating a slit-shaped light beam 82 long in the Y-axis direction is provided. , A one-dimensional position detecting element (one-dimensional PSD) 80 having a position detecting direction in the X-axis direction is arranged. With this arrangement, when the optical disk 53 is tilted about the Y-axis direction, the reflected light 81 is shifted in the X-axis direction accordingly. Therefore, the position in the X-axis direction for receiving the reflected light 81 changes with the inclination of the optical disk 53, and the inclination of the optical disk can be detected accordingly. Then, even if the surface shake occurs simultaneously, the position of the reflected light spot 81 does not change, so that only the inclination can be detected without being affected by the surface shake.

[0008]

However, in such a conventional reflection type photoelectric sensor, a one-dimensional PSD is required.
Alternatively, the two-dimensional PSD is used, and the inclination and the surface runout are detected separately or simultaneously, and only one position is measured for the surface runout or the tilt, respectively, so that the detection accuracy is poor.

For discrimination of an optical disc, a DVD (digital video disc) in a conventional optical disc apparatus is used.
And CD, LD (compact disk, laser disk)
The function of discriminating the type of an optical disc having a single-sided reproduction capability is realized by driving and focusing on an optical pickup unit, but the load on the optical pickup unit increases and the device becomes complicated. Further, it is necessary to drive the optical pickup unit at the time of the type determination operation, so that there is a problem that it takes time.

The present invention has been made in view of the above-mentioned drawbacks of the conventional example, and has as its object the purpose of determining the type of an optical disk by using a single reflection-type photoelectric sensor and determining the surface deflection and tilt of the optical disk. As well as
An object of the present invention is to increase detection accuracy and reduce detection time. Another object of the present invention is to provide an optical disc discriminating apparatus capable of discriminating at least three types of optical discs.

[0011]

According to a first aspect of the present invention, there is provided a reflective photoelectric sensor, comprising: a light emitting element for emitting a light beam toward an optical disk; a direction for detecting an inclination generated on the optical disk by rotation; A light-receiving position detecting means for outputting a change in a light-receiving position of a light beam in a direction orthogonal to the optical disk; and an optical disc by receiving the light beam emitted from the light emitting element and reflected by an optical disc recording layer of the optical disc by the light-receiving position detecting means. And a light discriminating means for discriminating the type of the optical disc, wherein the light emitting element and the light receiving position detecting means are arranged in a direction perpendicular to the direction of detecting the tilt of the optical disc.
The position of the recording layer of the optical disk differs depending on the type of the CD, LD, DVD, or the like.

According to a second aspect of the present invention, in the reflective photoelectric sensor according to the first aspect, a plurality of the light emitting elements are arranged along a direction in which the tilt of the optical disk is detected.

According to a third aspect of the present invention, there is provided a disk discriminating apparatus comprising: a light emitting element for emitting a light beam having a specific wavelength toward an optical disk; a light receiving means for receiving a light beam emitted from the light emitting element and reflected by the optical disk; Disc discriminating means for discriminating the position of the optical disc recording layer from the light receiving position of the light beam received by the light receiving means, disc discriminating means for discriminating the light reflection characteristics of the optical disc from the amount of light received by the light beam received by the light receiving means, It is characterized by having.

[0014]

In the reflection type photoelectric sensor according to the first aspect, when a CD or LD is mounted on an optical disk device or when a DVD is mounted, a light beam is applied to a recording layer of the optical disk by a light emitting element. The light receiving position of the reflected light differs depending on the position of the optical disk recording layer, and the light receiving position detecting means detects the light receiving position. Therefore, a CD or LD and a DVD are determined according to the light receiving position.

Further, since the light emitting element and the light receiving element are arranged in a direction orthogonal to the direction of detecting the tilt of the optical disk,
When the optical disk moves in parallel, the light receiving position of the light receiving element moves in a direction orthogonal to the direction of detecting the inclination of the optical disk, and the output in the direction orthogonal to the direction of detecting the inclination of the light receiving element changes. On the other hand, even when the optical disc is tilted in the tilt detection direction, the light receiving position of the light receiving element does not move in the tilt detection direction of the optical disc, and the output of the light receiving element in the tilt detection direction does not change.

Further, when the optical disc is tilted in the tilt detecting direction, the light receiving position of the light receiving element moves in the tilt detecting direction of the optical disc, and the output in the tilt detecting direction of the light receiving element changes. On the other hand, even if the optical disk moves in parallel, the light receiving position of the light receiving element does not move in the direction orthogonal to the direction of detecting the inclination of the optical disk, and the output in the direction orthogonal to the direction of detecting the inclination of the light receiving element does not change.

Therefore, in the reflection type photoelectric sensor according to the present invention, the position of the optical disk is detected at the position of the optical disk recording layer. Can be determined.

Further, the tilt of the optical disk and the parallel movement of the optical disk in the tilt detection direction can be detected simultaneously and separately by one light receiving element and at least one light emitting element. Therefore, the reflection type photoelectric sensor capable of detecting the parallel movement and the tilt of the optical disk can be made compact, and the cost can be reduced.

Further, according to the second aspect of the present invention, since the plurality of light emitting elements are arranged along the direction of detecting the tilt of the optical disk, the accuracy of detecting the tilt of the optical disk can be improved.

In the optical disc discriminating apparatus according to the third aspect, the difference in the position of the recording layer of the optical disc can be discriminated from the light receiving position of the light beam reflected by the optical disc and received by the light receiving means. It is possible to discriminate between optical disks having different optical disk recording layer positions, for example, a DVD and a CD or PD.

Further, since the light reflection characteristics of the optical disk can be determined from the amount of light beam reflected by the optical disk and received by the light receiving means, optical disks having different light reflection characteristics, such as a CD and a PD, can be used. Can be determined. In addition, since the light reflection characteristics of each optical disc differ depending on the wavelength of the light beam, the accuracy of discriminating the type of optical disc can be increased by using a light emitting element having an appropriate emission wavelength according to the type of optical disc to be discriminated. .

Therefore, in the optical disc discriminating means according to claim 3, at least three kinds of optical discs can be discriminated by combining the two kinds of disc discriminating means. In addition, discrimination of various types of optical discs becomes possible.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION

(First Embodiment) As shown in FIG. 1, a reflection type photoelectric sensor according to the present embodiment is built in an optical disk apparatus, and a spot-shaped light beam is formed near an outer peripheral surface of a rotating optical disk A. B and a two-dimensional position detecting element 2 (Position Sensitive Device, hereinafter 2) capable of detecting a two-dimensional position as a light receiving element for receiving a reflected light spot of the light beam B reflected on the outer peripheral surface. Dimensional PSD
) Is provided.

Further, a signal processing circuit 30 for processing a detection signal of a two-dimensional PSD 2 which will be described later is provided with a light receiving position for obtaining the amount of surface shake and inclination of the optical disk A based on the detection signal of the two-dimensional PSD 2 by the same reflected light spot. It has a detecting means.

The two-dimensional PSD 2 has a rectangular light receiving surface 2a, and is provided with four electrodes x1, x2, y1, and y2 for taking out detection signals at the centers of four sides forming the outer periphery of the light receiving surface 2a. The electrodes x1 and x2 are arranged in the radial direction (X direction) of the optical disk A so as to face each other. Similarly, the electrodes y1 and y2 are arranged in the edge tangent direction (Y direction) of the optical disk A.
, And the electrodes x1, x2, y1, and y2 are connected to the signal processing circuit 30, respectively.

The signal processing circuit 30, as shown in FIG.
At the time of the detection operation, the detection signal current is taken out from each of the electrodes x1, x2, y1, and y2, and amplified and subjected to I / V (current / voltage) conversion by the light receiving amplifiers 31 to 34, thereby obtaining the voltage signal Vx1,
Vx2, Vy1, Vy2, and adders 36, 38,
The shift amount δx of the light receiving position in the X direction and the shift amount δy of the Y direction in the light receiving position are obtained by the subtracters 35 and 37 and the dividers 39 and 40, and signals indicating these δx and δy are converted into the inclination detecting unit 42 and the surface shake detecting unit. Output to 41. The inclination detector 42 calculates the inclination of the optical disc A from δx, and the surface deviation detector 41 calculates δ
The surface deflection of the optical disk A is calculated from y, and each calculation result is output to the pickup unit of the disk reading device. The optical disc apparatus further includes a disc discriminating unit 43 that detects a difference in the position of the recording layer of the optical disc A when the optical disc A is set in the optical disc device and discriminates the type of the optical disc A. The pickup section moves the pickup in accordance with an output signal from the signal processing circuit 30 to maintain parallelism with the optical disc A and a constant distance.

An arithmetic expression for signal processing is, for example, δx = k ·
(Vx1−Vx2) / (Vx1 + Vx2), δy = k ·
(Vy1−Vy2) / (Vy1 + Vy2). Here, k is a proportionality constant.

As shown in FIG. 3A, a DVD has a reflective layer 12 having a recording layer on both sides and a resin layer 11.
Formed within. The CD and LD are shown in FIG.
As shown in FIG. 2, a reflective layer 14 having a recording layer on one side is formed on one side of a resin layer 13. That is, DVD
In the case of CD and LD, the thickness from the surface of the resin layer on the light projection side to the reflection layer is different, and the light receiving position of the reflected light beam C is shifted in the Y-axis direction.

When the optical disc A is set in the optical disc device, the disc discriminating means 43 takes out a detection signal from the electrodes y1 and y2, and is set in advance to a light receiving position between the light receiving position of DVD and the light receiving position of CD and LD. By comparing with the set value, it is determined whether the disc is a CD, LD or DVD, and the result is outputted to the optical disc device.

This makes it possible to provide a function of determining the type of the optical disk A in the same manner as the measurement of the surface runout without adding a special member to the optical disk device.
Since the load on the optical pickup unit can be reduced and the type of the optical disc A can be determined without driving the optical pickup unit, the time from setting the optical disc A to performing the type determination and starting reading is reduced. Can be shortened.

The light emitting element 1 and the two-dimensional PSD 2 both face the same surface of the optical disk A, and are arranged side by side in the disk radial direction. When the optical disk A is not shaken, the optical disk A is located at the center of the light receiving surface 2a of the two-dimensional PSD 2. It is adjusted so that the reflected light spot from the lens enters. Thus, as shown in FIG. 1A, when the optical disk A is tilted with respect to the rotating surface, the light receiving position of the reflected light spot is shifted in the radial direction of the disk, and as shown in FIG. When the disk is moved up and down in parallel with the disk, the disk is shifted in the tangential direction. Normally, both shifts are combined shifts.

In the above configuration, when the optical disc A is set in the optical disc apparatus and reading is started, first, the reflection type photoelectric sensor starts operation, and the light emitting element 1 emits the light beam B to the optical disc A. The reflected light spot from the optical disc A enters the center of the light receiving surface 2a of the two-dimensional PSD 2. And the disk discriminating means are the electrodes y1, y
2 to extract the detection signal from the DVD, and
By comparing with a set value set at a light receiving position between the light receiving positions of D and LD, it is determined whether it is a CD, an LD or a DVD, and the result is output to an optical disk device.

Then, the optical disk A starts rotating, and the light receiving position of the reflected light spot shifts in the radial direction of the disk when the optical disk A is tilted with respect to the rotating surface, and moves up and down in parallel with the rotating surface. Deviates in the tangential direction of the disc. Normally, both shifts are shifted in the direction in which they are combined.

Subsequently, the signal processing circuit 30 controls each electrode x
1, x2, y1, and y2, detection signals are taken out, amplified and I / V-converted by a light-receiving amplifier, and voltage signals Vx1,
Vx2, Vy1, and Vy2, and the light-receiving position detecting means sets the surface-movement detecting unit 41 and the inclination detecting unit 42 based on the deviation amount δx in the X direction and the deviation amount δy in the Y direction of the light-receiving position. The amount of inclination is obtained and output to the pickup unit of the disk reading device.

The pickup section moves the pickup in accordance with the output signal from the signal processing circuit 30 to perform a reading operation while keeping the distance from the optical disk A constant and maintaining the parallelism.

As described above, since the surface runout and tilt at one location of the optical disc A are simultaneously detected by one set of light receiving and emitting elements, the apparatus can be downsized and the cost can be reduced.

(Second Embodiment) In this embodiment,
In the first embodiment, as shown in FIG.
Two light emitting elements 1 are arranged side by side in the direction (X-axis direction) orthogonal to the traveling direction of the projection beam A, and the two-dimensional PSD 20 is used to receive a plurality of reflected light spots C1 and C2 from the light emitting elements 1a and 1b. The light receiving surface 20a is widened in a direction perpendicular to the traveling direction of the light beams B1 and B2, and the light receiving position detecting means detects the amount of surface deflection by a detection signal from the two-dimensional PSD 20 that receives a plurality of reflected lights C1 and C2 at the same time. And the amount of inclination are detected.

When the optical disc A is inclined with respect to the rotating surface, the light receiving positions of the reflected lights C1 and C2 are similarly shifted in the radial direction of the disc as shown in FIG. 4B. At this time, the output signals Vx1 and Vx2 extracted from the two-dimensional PSD 2 are combined with the respective reflected lights C1 and C2 by superimposing photocurrents generated by receiving the respective reflected lights C1 and C2.
The values are proportional to the sum of the shift amounts of the two output signals Vx1 and Vx2.
Of the center of gravity δx = f (Vx1, Vx2), and the amount of inclination is detected with high accuracy.

It is needless to say that the light receiving element is not limited to the two-dimensional PSD, but may be changed within the scope of the present invention. For example, a multi-segment element such as a 4-segment PD may be used. Further, the displacement amount δx = f (Vx1, Vx
f in x2) may be changeable by an external operation.

(Third Embodiment) FIG. 5 is a block diagram showing an optical disc discriminating apparatus 90 according to the present invention. The optical disc discriminating device 90 has a function of discriminating the type of the optical disc based on the position of the recording layer of the optical disc (first disc discriminating means 43), and the amount of reflected light (e.g. Reflectance)
A function of determining the type of the optical disk from the amount of reflected light (second disk determining means 92), and a disk type determining unit 93 for determining the type of the optical disk by integrating the determination results of both disk type determining means. . Further, similarly to the reflection-type photoelectric sensor of the first embodiment, the optical sensor also has a function of detecting surface runout and tilt of the optical disk.

As the light emitting element 1, an element having a narrow emission wavelength range, that is, a monochromatic light emitting element is used. Or,
The filter emits monochromatic light.

The first disc discriminating means 43 discriminates the optical disc according to the position of the recording layer, as in the first embodiment. That is, the electrode y of the two-dimensional PSD2
1, the detection signal current output from y2
At 1 and 32, amplification and I / V (current / voltage) conversion are performed to convert the signals into voltage signals Vy1 and Vy2, and the adder 36, subtractor 35 and divider 40 determine the shift amount δy of the light receiving position in the Y direction. Then, the signal indicating this δy is converted to
Output to The first disc discriminating means 43 calculates the position of the recording layer of the optical disc A from δy.

Therefore, according to the first disc discriminating means 43, an optical disc whose recording layer is located at the center of the disc, such as a DVD, a CD-ROM (read-only CD), a CD-R It is possible to distinguish an optical disc whose recording surface such as a writable write-once CD or a PD (Phase Change Dual) is located on the surface of the disc. The first disc discriminating means 43 outputs the discrimination result to the disc type discriminating section 93.

The second disk discriminating means 92 has a two-dimensional P
The reflected light amount from the optical disk recording layer is compared with a comparative value set in advance using the measurement result of the reflected light received amount by SD2. That is, the electrodes x1, x2, y of the two-dimensional PSD2
1, the detection signal current output from y2
Amplification and I / V (current / voltage) at 3, 34, 31, 32
Conversion is performed to generate voltage signals Vx1, Vx2, Vy1, and Vy.
After the conversion to 2, the adders 38, 36, and 91 add up the total received light amount, and output a signal indicating the total received light amount to the second disk discriminating means 92. The second disc discriminating means 92 discriminates the type of the optical disc A from the total amount of received light, and outputs the result to the disc type discriminating unit 93.

According to the results confirmed by the inventors of the present invention, the wavelength dependence of the reflectance (spectral wavelength characteristic of the reflectance) in the recording layer of each optical disc shows its own characteristic as described later. It has been found that the type of the optical disk can be determined using these characteristics.

The disc type discriminating section 93 is based on outputs from the first and second disc discriminating means 43 and 92.
More specifically, the type of the optical disc is finally determined comprehensively based on the amount of light reflected by the recording layer (reflectance) and the position of the recording layer.

FIG. 11 shows a DVD-ROM, CD-ROM, CD
FIG. 10 is a graph showing the result of measuring the reflectance (relative reflectance) of light reflected on the recording surface of these optical discs by selecting R and PD, and showing the [spectral wavelength characteristic], where the vertical axis indicates the relative reflection of the recording layer. And the horizontal axis indicates the wavelength of the projected light. As can be seen from FIG. 11, DVD-ROM, CD-R
Optical disks such as OM, CD-R, and PD have different spectral wavelength characteristics from each other. Therefore, by detecting the difference between these spectral wavelength characteristics, the type of the optical disk can be identified. In particular, even if the position of the optical disk recording layer is the same, the type can be identified by the difference in the spectral wavelength characteristics, and the resolution of the type determination of the optical disk is increased. Also, if light of a specific wavelength is used, the type of optical disc can be determined from the difference in reflectance without investigating spectral wavelength characteristics over a wide wavelength range. In particular, the discrimination can be made with high accuracy by using light having a wavelength at which the difference in reflectance between the optical discs to be discriminated is the largest. The second disk discriminating means 92 is based on such a principle.

As the type of optical disk, DVD-RO
Considering the case of discriminating M, CD-ROM, CD-R, and PD, the DVD-ROM and the other optical disc can be discriminated by the first disc discriminating means 43.
Light in a wavelength range in which the reflectance of the ROM, CD-R, and PD varies most may be used. As can be seen from FIG. 11, such a wavelength range is about 550 to 550.
Light of 750 nm is preferably used. In particular, it is most preferable to use light of about 660 nm, which is the center of this wavelength range and has been confirmed experimentally.

The difference in the amount of reflected light from each optical disk (large, medium,
Table 1 shows small) and the positions of the recording layers (far and near).

[0050]

[Table 1]

Accordingly, the optical disk discriminating apparatus 90 of the present invention
In this case, the light of about 660 nm is emitted from the light emitting element, and the second disk discriminating means 92 divides the amount of reflected light into large, medium, and small compared with the threshold value, thereby achieving C
D-ROM, CD-R, and PD can be distinguished.
Since the VD-ROM can be distinguished from other optical discs, the disc type discriminating section 93 uses a DVD-ROM, a CD-R
OM, CD-R and PD can be distinguished.

From FIG. 11, DVD-ROM, CD-R
Approximately 550 to 750 nm is selected as the light wavelength for discriminating between OM, CD-R, and PD, but it goes without saying that other wavelengths of light may be used depending on the accuracy of detecting the amount of reflected light. For example, a wavelength of about 850 to 1100 nm (excluding the vicinity of the wavelength where the spectral wavelength characteristics intersect) can be used.

It goes without saying that if the type and number of optical discs to be determined are different, the light wavelength to be used also changes. For example, if it is not necessary to determine whether the disc is a CD-R or a CD-ROM, the discrimination between FIG.
Light of 0-1300 nm can also be used.

In this embodiment, DVD-ROM, CD-ROM, CD-R, and PD are assumed as types of optical disks, but data can be obtained by measuring spectral reflection characteristics of other types of optical disks. Thereby, more types of optical discs can be identified. In particular, DV
It is also possible to discriminate between a D-ROM and a DVD-R (write-once DVD).

When the reflectance of the recording layer of some of the optical disks to be determined is close to the light wavelength, light of a light wavelength whose reflectance is more than a certain distance is also used. May be. In other words, by using two or more light emitting elements having different emission wavelengths for discrimination of optical discs, it is possible to discriminate more accurately and more types of optical discs. In this case, the light receiving section may separate and receive light of different wavelengths using a color filter or the like.

[0056]

According to the present invention, the type of the optical disk can be determined by detecting a change in the distance of the recording layer of the optical disk without adding a special member.

Further, a position detecting element or a multi-segment element is used as a light receiving element, and both are arranged in the optical axis direction or a direction orthogonal to the optical axis. The shake amount and the tilt amount can be detected simultaneously.

Further, by increasing the measurement range in the direction orthogonal to the optical axis and amplifying and detecting the amount of displacement of the center of gravity of the reflected light on the light receiving element, the accuracy of detecting the amount of tilt of the optical disk can be improved. it can.

Furthermore, since the above configuration can be combined with one reflection-type photoelectric sensor without adding a new member, an excellent effect that a high-performance reflection-type photoelectric sensor can be provided can be provided. is there.

Further, according to the optical disc discriminating apparatus of the present invention, various kinds of optical discs can be discriminated accurately based on the position of the recording layer of the optical disc and the reflectance characteristics thereof.

[Brief description of the drawings]

FIGS. 1A and 1B show a reflection-type photoelectric sensor according to a first embodiment of the present invention, in which FIG. 1A is a diagram showing a state of detecting a tilt of a disk, and FIG. FIG.

FIG. 2 is a block diagram illustrating a signal processing circuit.

FIG. 3A is a diagram illustrating a state of discriminating a DVD, and FIG. 3B is a diagram illustrating a state of discriminating a CD and an LD.

FIG. 4A is a diagram illustrating a reflection-type photoelectric sensor according to a second embodiment, and FIG. 4B is a diagram illustrating a state in which the tilt of a disk is detected.

FIG. 5 is a block diagram showing an optical disc discriminating apparatus according to a third embodiment of the present invention.

FIG. 6 shows a case where the type of an optical disk is used as a parameter.
FIG. 3 is a diagram illustrating spectral wavelength characteristics of reflectance of a recording layer.

FIG. 7 is a view showing a conventional reflection type photoelectric sensor.

FIG. 8A is a longitudinal sectional view showing an example of a conventional reflection-type photoelectric sensor, and FIG. 8B is a transverse sectional view of the same.

9A is a diagram illustrating a state in which the optical disk is inclined with respect to the rotation surface, and FIG. 9B is a diagram illustrating a state in which the optical disk is out of plane.

FIG. 10 is a diagram showing a conventional reflection-type photoelectric sensor for detecting surface runout of an optical disk.

FIG. 11 is a diagram showing a conventional reflection type photoelectric sensor for detecting the inclination of an optical disk.

[Explanation of symbols]

 1, 1a, 1b Light emitting element 2, 20 Two-dimensional PSD 41 Surface runout detector 42 Tilt detector 43 (First) disk discriminating means 90 Optical disc discriminating device 92 Second disc discriminating means 93 Disc type discriminating part A Optical disc B, B1, B2 Projection beam C, C1, C2 Reflection beam

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical display location G11B 19/12 501 G11B 19/12 501J

Claims (3)

[Claims] A light emitting element for emitting a light beam toward an optical disk, and a light receiving element for outputting a change in a light receiving position of the light beam in a direction in which a tilt generated in the optical disk due to rotation is to be detected and a direction orthogonal to the direction. Position detecting means, and disc discriminating means for discriminating the type of the optical disc by receiving the light beam emitted from the light emitting element and reflected by the optical disc recording layer of the optical disc by the light receiving position detecting means, The reflection type photoelectric sensor, wherein the light receiving position detecting means is arranged in a direction orthogonal to a direction in which the inclination of the optical disk is detected. 2. The reflection-type photoelectric sensor according to claim 1, wherein a plurality of the light emitting elements are arranged along a direction in which the inclination of the optical disk is detected. 3. A light emitting element for emitting a light beam of a specific wavelength toward an optical disc; a light receiving means for receiving a light beam emitted from the light emitting element and reflected by the optical disc; and a light receiving means for receiving the light beam received by the light receiving means. A disc discriminating unit for discriminating a position of the optical disc recording layer from a light receiving position; and a disc discriminating unit for discriminating a light reflection characteristic of the optical disc based on an amount of a light beam received by the light receiving unit. Optical disc identification device.