KR0137084Y1 - An optical pickup device for dvd - Google Patents

Abstract

The present invention relates to an optical pickup device for DVD, and in particular, to provide an optical pickup device for DVD that is simple in structure and compatible with CD, so that information can be read through selective optical pickup, preventing product defects, productivity and use In order to improve efficiency, the optical pickup device is provided with a hologram pickup module so as to be compatible with DVD and CD.

Description

Optical pickup device for DVD

1 is a block diagram of a conventional optical pickup device.

2 is a signal control diagram of the present invention.

3 is a block diagram of the optical pickup device of the present invention.

4 is another embodiment of the present invention.

* Explanation of symbols for main parts of the drawings

101: optical disk 102: objective lens

103: collimating lens 104: beam splitter

105: laser diode 106: hologram pickup module (HPM)

107,108: sensor lens 109: diffraction plate

110: photodiode

The present invention relates to an optical pickup device for a DVD (Digital Video Disk), and more particularly, to an optical pickup device that can simplify the structure of the product and thereby increase productivity while having a compatibility between a CD and a DVD. will be.

Conventional optical pickup devices include three types of twin lens method, holographic lens method, and LCS (LCS) method. The general structure of these optical diodes emits 635 nm or 650 nm laser as shown in FIG. (7), a diffraction plate (6) diffracting and dividing the bundle of light emitted from the laser diode (7) into multiple strands, and the light passing through the diffraction plate (6) and the prism block (5) in parallel A collimating lens (4) for making, an LCS (3) acting as an aperture to tighten and widen the light passing through the collimating lens (4), and incident to the optical disc (1) through the LCS (3) The objective lens 2 for condensing the diameter of the light to 1 μm or less, and the light reflected from the optical disk 1 is partially reflected while passing through the prism block 5 and then adjusted to a shape suitable for the photodiode 10. It consists of sensor lenses (8, 9).

Referring to the conventional operation configured as described above, first, the laser emitted from the laser diode (7) is passed through the diffraction plate (6) and separated into 0th order and ± 1st order light, so that the prism block (5), collimating lens (4), LCS (3), the optical lens 1 is focused through the objective lens 2 in order. Then, the reflected light reaches the objective lens 2, the LCS (3), the collimating lens (4) and the prism block (5), and some light passes through the prism block (5) and some is reflected. The photodiode 10 converts light incident through the sensor lenses 8 and 9 into a current again and changes into a current according to its intensity.

An important function of such a system is that the position of the optical disc 1 and the objective lens 2 should be operated at a position two-dimensionally appropriate (within ± 0.5 μm on one side and within ± 0.05 μm on one side). One side is called a focus servo and the sensor lenses 8 and 9 are required for this purpose.

And the higher degree is the track servo (Track servo), for which the diffraction plate (6) is required and the configuration and adjustment of the photodiode (10) is difficult.

In other words, the diffraction plate 6 splits the light into three pieces so that they are properly placed on the track on the optical disc 1. The CD or DVD has a different pitch and can only be used on either side. Therefore, one side uses only one light.

In this way, when the focus and the track are servoed, the information recorded on the optical disc 1 is converted into RF (Ratio Frequence) through the system and entered into the DVD.

However, such a prior art configuration is difficult to manufacture the first part. In particular, there are many difficulties in manufacturing the LCS 3, and in the twin lens method, a problem arises in driving characteristics since it must be driven simultaneously to control two lenses.

In addition, in terms of performance, an offset (offsec) occurs due to the use of the one-beam (1-Beam) method for the track servo, resulting in a decrease in overall performance.

In view of this point, the present invention is equipped with a hologram pickup module (hereinafter referred to as HPM) for converting CD information into an electrical signal so that the DVD and CD can be compatible with each other. The goal is to increase productivity.

The present invention will be described in detail below with reference to the accompanying drawings.

First, as shown in FIG. 3, the laser diode 105 for 635 nm or 650 nm, which emits a laser and receives the reflected light, and the light emitted from the laser diode 105 are diffracted into several strands. The main beam is divided into a diffraction plate 109, a beam splitter 104 which reflects or transmits and divides the light divided by the diffraction plate 109, and emits 780 nm laser beam toward the beam splitter 104. HPM 106 for receiving light, collimating lens 103 for transmitting light emitted from beam splitter 104 in parallel, and light passing through collimating lens 103 to focus and focus on disk 101. The objective lens 102, the photodiode 110 for converting the light emitted from the laser diode 105 and reflected back to the current, and the light coming into the photodiode 110 to make the appropriate shape With sensor lens (107,108) Configured.

When reading the information of the DVD on the disk 101 in this configuration, the optical disk 101 → the objective lens 102 → the collimation lens 103 → the beam splitter 104 → the sensor lenses 107 and 108 → the photodiode 110. When the CD information is read, the system is composed of an optical disc 101, an objective lens 102, a collimating lens 103, a beam splitter 104, and an HPM 106.

First, in the case of a DVD, the laser emitted from the laser diode 105 passes through the diffraction plate 109, the beam splitter 104, the collimation lens 103, and the objective lens 102, and then passes through the optical disk 101. Focus on the order of μm. This focal point is reflected again and passes through the objective lens 102, the collimating lens 103, the beam splitter 104, and the sensor lenses 107 and 108 to be received by the photodiode 109.

At this time, since the three-beam method using the diffraction plate is used, the offset does not occur in the tresovo.

In the case of the CD, when the laser diode 105 is turned off and the 780nm HPM 106 is operated, the information is read while focusing on the disc with a focus of about 1.6 μm, and the focus is reflected again. Incident on the photodiode embedded in the HPM 106, no offset occurs and the adjustment is simple.

In addition, FIG. 4 may contribute the same performance by installing a laser coupler 206 instead of the HPM 106 as another embodiment of the present invention.

The present invention as described above is designed to improve the efficiency of use of the product by allowing the compatibility with the CD with the development of a simple structure and easy to manufacture parts DVD.

Claims (2)

A first light emitting means mounted on the semiconductor substrate to emit a laser beam, diffraction means for tracking control by dividing the beam emitted by the light emitting means into a plurality of beams, and a beam generated by the diffraction means in the direction of the optical disc A beam converting means for reflecting the light, a first lens for making the beam radiated through the beam converting means to be a parallel beam, and a second lens for focusing the light passing through the first lens to focus on the disk And converted into a large and small signal of current according to the received amount of light received through the first lens and the second lens, passed through the beam conversion means, and passed through the plurality of third lenses for focus control. Second light emitting means for diffracting a laser beam to read only CD information, and a beam of the second light emitting means comprises the beam converting means and the first len And an optoelectronic means for converting the light reflected on the disk surface into the magnitude of the current according to the amount of light received after sequentially passing through the second lens. The optical pickup apparatus of claim 1, wherein the first light emitting means comprises a hologram pickup module that emits a beam to read only CD information and converts a light signal into an electrical signal.