JPS6192444A - Optical pickup - Google Patents

Abstract

PURPOSE:To improve the S/N of a signal current output of a photodetector without special constitution such as shield by connecting a photodetector and a current-voltage converting element into one integrated circuit and minimizing the connection length of the signal current output of the photodetector and the current-voltage converting element converting the current output into voltage. CONSTITUTION:The signal current output of the photodetector 4 is subjected to voltage conversion directly in an integration circuit 5 by means of the current-voltage converting element by constituting the integrated circuit of the photodetector 4 and the current-voltage converting element. Thus, the effect of noise on the signal current output of the photodetector 4 is minimized and no special structure such as shield of the signal current output of the photodetector 4 is not required. Further, even when the photodetector is used as a dynamic element in the optical reproducing device or the like, the limitation of the operation by a shield wire is not required and smooth operation is realized.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a photodetector element that converts light modulated by an information track of an optical disk into an electrical signal, and a current detector that converts the signal current output of the photodetector element into a voltage. - It relates to an optical pickup composed of a voltage conversion element.

Conventional configuration and points in between and points Conventionally, as shown in Fig. 1, an optical pickup includes a photodetector element 1 that converts light modulated by an information track of an optical disk into an electrical signal, and a signal from the photodetector element. It is equipped with a current-voltage conversion element 2 that converts current output into voltage, and the current flow path between them is a long lead wire 3.
etc. are used to connect the parts that make up the photodetecting element 1 and the current-voltage converting element 2 independently to each other. :
*The rtl parts were not the same or close to each other. Therefore, the photodetection element 1 and the current-to-lightning noise ratio were not good. For this reason, in order to improve the signal-to-noise ratio, a shielded wire or the like has been used to protect the signal current between the photodetector element 1 and the current-voltage converter element 2 from noise. However, when the photodetecting element 1 is included in a dynamic element such as an optical reproducing device, /
- When it comes to cold wire, the wire itself becomes thick and hard, and it suffers from the disadvantages that it becomes difficult to operate, and that it has to be shielded, which is a long-lasting construction.

OBJECTS OF THE INVENTION It is an object of the present invention to provide an optical pickup capable of improving the signal-to-noise ratio of the signal current output of a photodetecting element without using a special configuration called a rolled.

Structure of the Invention The optical pickup of the present invention combines a photodetection element and a current-voltage conversion element into one integrated circuit, and combines a signal current output of the photodetection element with a current-voltage conversion element that converts the signal current output into a voltage. This feature has the advantage of minimizing the connection length of the photodetector, improving the signal-to-noise ratio of the signal current output of the photodetector, and allowing for miniaturization.

DESCRIPTION OF EMBODIMENTS FIG. 2 shows an optical pickup in an embodiment of the present invention. In FIG. 2, 4 is a photodetecting element;
Reference numeral 5 denotes a current-voltage conversion element including the photodetection element 4 and its integrated circuit. In this way, the photodetection element and the current-voltage conversion element are integrated. By configuring an integrated circuit of the photodetection element 4 and the current-voltage conversion element including the photodetection element 4 in this way, the current output of the photodetection element 4 is directly transmitted to the current-voltage conversion element in the integrated circuit 5. Since the voltage is converted by , the influence of noise on the signal current output of the photodetecting element 4 can be suppressed, and a special structure in which the signal current output of the photodetecting element 4 is 7-derivated is not required or required. In addition, in the case of an optical reproducing device in which a photodetecting element is included as a dynamic element, the restriction of ω operation due to the 7-fold line is not added, and smooth operation is realized. . Furthermore, the pickup in the optical reproducing device employs an optical system using a polarizing beam splitter and a nof mirror, and the photodetector element receives only a weak amount of light. On the other hand, there are certain limits to the sensitivity and conversion ability of the photodetector itself. Therefore, integrating the photodetection element and the current-voltage conversion element into an integrated structure as in this example greatly improves the signal-to-noise ratio, and reduces the number of leads to the connected electronic circuit. Great improvements can be made in improving performance and reducing costs without installing any wires at all.

In this example, the integrated structure of the photodetection element and the current-voltage conversion element was explained, but the same structure can also be applied to the integrated structure of the photodetection element, including the servo control circuit necessary for the optical reproducing device. Needless to say, it is effective.

Effects of the Invention The present invention aims at monolithic integration by configuring a photodetection element and a current-voltage conversion element on the same element, and the integration greatly reduces the signal-to-noise ratio of the signal current output of the photodetection element. It is possible to improve the signal current output without requiring any special structure such as rolling the lead wires to the electronic circuit to which it is coupled, improving performance, reducing cost, and miniaturizing the circuit. What are the benefits that can be realized?

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a conventional optical pickup, and FIG. 2 is a block diagram showing an example of an optical pickup of a non-explosion [moon]. 4...Photodetection element; 5...An integrated circuit including a photodetection element and a current-voltage conversion element. Figure 1 Figure 2

Claims (1)

[Claims] A photodetection element that converts light focused on an optical disk and modulated by an information track recorded on the disk into an electrical signal, and a current-voltage conversion element that converts the output current of the photodetection element into a voltage. An optical pickup characterized by combining the following through integration.