JPS6038744A - Photodetecting element for detection of optical information - Google Patents

Abstract

PURPOSE:To reduce the effect of the thickness of substrate of a photodetecting element by shaping an edge into wedge shape which functions as a knife edge of a track detecting photodetecting element which masks a part of a reflected luminous flux given from an optical information recording medium and detects a focal point. CONSTITUTION:For a photodetecting element 8, a photodetecting surface 12 is formed on a substrate 11 and the substrate 11 has about 1-2mm. thickness. As a result, a part of the reflected luminous flux fed from a disk is masked by the edge face of the element 8. When the remaining luminous flux is made incident on a focus detecting photodetecting element 9, the luminous flux is partially reflected by the end face of the element 8 and turned into the flare light 13. Then a part of the luminous flux to be received by a focus detecting photodetecting element B is received by a photodetecting element A. Here an edge functioning as a knife edge of the element 8 is formed into a wedge shape. At the same time, the end face of the substrate 11 is painted in black or changed into a coarse surface. Thus it is possible to reduce the light 13 and prevents the drop of the detection signal level.

Description

Detailed Description of the Invention (εl′) The present invention is based on the original 11 eyes (1), and the light receiving element for the reconnaissance weapon (1), in particular, the focal point of the light emitting group (1) is enlarged. Lu JY) 1 for Mizuko receiving light
, j (+1: American technology) The original pickup for optically taking the 1;'i width recorded on the original disk stop to the trunk in operation. In order to track correctly and take off the thfk, and at the same time maintain the focus on the trunk, set the tracking and focus state to 1, and set the optical pickup position i; Iru Jin is well known.

The Naifetsu method is known as one of these bz [dust extraction methods 1'].

FIG. 1 shows an optical pink-up optical system υ that performs focus projection and trunk projection using the conventional re-knife edge method.

The original RL from the light u1 of a semi-dedicated laser, etc. is reflected by the Kaguri/Glenn 2 as an F-Ti source TL, the beam sinter 3, the 1/4 wavelength plate 4, and the objective lens 5. The disk value 6101 is set to a bond value of about 16 μm.

The reflected light beam from the disk surface 6 is converted into (1) and S source beam by the objective lens 5, and is converted directly into the incident light by the quarter-wave plate 4.
Waiting for a biased C plane, u negative 1 eye L, υ, Beef N Splinter 3, Blood 9, Thread C lens 7, it becomes a condensed light. A part of this prefecture is 0 to 1% i (as shown in Figure 1), the luminous flux 10 occupies approximately half, and the track detection m is divided into 2 degrees C and D parallel to the track T direction. Light receiving element 8
The remaining light beam is incident on this track projection light receiving element 8.
The light enters the light receiving element 9 for lighting detection, which is divided into two parts A and B parallel to the edge of the light.

Figure 2 shows the focus projection of this optical pickup.
shows. The ring edge of the light-receiving element 8 is formed by a knife-engineering mechanism, and as shown in FIG. [?1
) becomes large, the Akita element's output is A (II) as shown in (b) of the same figure, and conversely, the output of the ηh group that approaches as shown in (C) of the same figure is A). By comparing the outputs of the pixel elements B and A, the thermal state can be determined.

On the other hand, track projection #1 (light receiving element 8 is shown in FIG. 3(a)
If the suhonto is correctly placed on the trunk as shown in K, the outputs of production elements C and D will be equal, but as shown in Fig. 1gJ (b
) If a deviation noise occurs from the trunk as in f7), the output of one force of C or D becomes large during the ELK on the other side.

The focal point of each of these small stones is 1μm+1,
The track projection hO11 μm is traced.

In this optical system, the light receiving element 8 for projecting a track also serves as a knife, and a problem arises when the disk 6 moves away from the objective lens 5.

That is, there is no problem if the light-receiving element 8 is thin enough to be used as a decoration, but if the light-receiving surface 12 is integrally formed on the plate 11 having a thick layer, as shown in Figures 2 and 4, There is.

In this way), when using a photodetector with 5 − υ, the 5th
As shown in the figure, a part of the original light is reflected by the end face of the light receiving element and becomes flare light 13, and part of the luminous flux υ that should originally be received by the focusing light receiver 350B is received by A. becomes.

In particular, the photodetector for trunk detection No. 8.
It is known that by setting the TL to receive light at 60% or more, the ht II of the track projection and focal point remization will increase, and in the original arrangement i'i like Jin, the beam When P receives and approaches element 8, that is, when P is far away, rBJ 1 mouth becomes 92 □
.

Moreover, if there is a gap in the K-element (the detection limit is when the beam waist P occurs in the light-receiving W element 8), the detection limit is narrowed accordingly.

lit button, the substrate 11 has a thickness of 1 to 2 mm, and the light receiving surface 1
2 tJ: 14/, the thickness of the scissors is 10 μm, and the influence of the thickness of the substrate ζ゛15 is large.

(Confession of the Invention 9 This invention eliminates the influence on the thickness of the substrate of the light receiving element,
f,, we are trying to find a light 1otν of a kite with a large launch axis, where i<t.

(The light emitting element of the present invention has a light letter arrangement εI+ 1). As shown in 61st Prisoner (a) and (b), Su15 Toko Lo
The f'+ia edge t which is placed inside is formed into a rust shape.

As a result, the edges of the nice edge portion and the edges of the light receiving surface itself become thinner due to the casing. In addition, by applying black wide coating treatment or making the surface rough, the flare light 1
It can be reduced by 3.

(Effect of "Emission") Since this invention has the above υ configuration, the trunk IIE
Even if the light-receiving element 8 is used as a knife edge, the focus detection axis circumference can be expanded depending on its thickness. Sk, straw, the 7th and 1st projection f-i
When the light-receiving element 8 is 1!j' as shown by ``r'', the focal projection anus S is formed by the thick υ distance wax as shown in the point gland O in the figure.
A parrot that is shaped like a wedge, as in "Maru ga kono yuyu" [! Like, fr-, out ν11v! is when the knife is sharp enough;
Sea urchin position [2 Uru.

1, in Figure 7, the projection (r'+ level is awa surname °C
However, if flare is caused by the young edge of the light receiving element 8V,
-The level of g-11 is decreasing every month. This light II
With +J, it is possible to prevent one generation below the 4-f level.

[Brief explanation of drawings]

Figure 1 shows the optical arrangement of the light ft' + ψ1 (v! output storage) by the Naifetsu method, Figures 2 and 3 show the
liA5? , clearly, Figure 4 is a perspective view of a conventional light receiving element,
Figure 5 is a diagram illustrating the toy that occurs at the edge #t46
The figure shows fli! of the light receiving element of this invention. I m1 figure and perspective view j. Figure 7 shows focus detection number 1d Figure 1: Laser 2: Conflict lens 3: Beam splitter 4: 1/4λ plate 6: Plasma disk surface 8
Light-receiving element for focusing and outputting 9: Light-receiving element for focusing and outputting 11: i/i; plate 12: Red-receiving surface 13:7 Layer light patent applicant Introduction 11. Rico - Patent attorney representing applicant VLij,'A LiJ(
1 other person)

Claims (1)

[Claims] Former 11'' news! [4] A knife is provided to receive a part of the reflected light beam from the recorder, and the dividing line in line with the track is turned into an image. 'F tij trunk saving lJ,i
It is said that the 91111 green shrine was carved into a wedge shape, which is a light-receiving water child and acts as a knife.
``Light information with ry'Q 8j #lJ receiver binary; child