KR0177722B1 - Opticl pick-up device - Google Patents

Abstract

The present invention relates to an optical pickup device, 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, and improving productivity and utilization efficiency. It is to improve, it is provided with a plurality of hologram pickup module that can act as a photodiode and a laser diode at the same time.

Description

Optical pickup device

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 an optical pickup device of the present invention.

Figure 4 (a) (b) is another embodiment of the present invention.

* Explanation of symbols for main parts of the drawings

101: optical disk 102: objective lens

103: collimation lens 104: flat beam splitter

105,106: Hologram Pickup Module (HPM)

BACKGROUND OF THE INVENTION 1. Field of the Invention 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 a product and thereby increase productivity while having a compatibility between a CD and a DVD. will be.

Conventional optical pickup apparatus has three types of twin lens method, hologram lens method, and LCS (LCS) method. Looking at the general configuration thereof, a laser that emits a laser of 635 nm or 650 nm as shown in FIG. A diode 7, a diffraction plate 6 which diffracts the laser light emitted from the laser diode 7 and divides the light into multiple strands, and the light passing through the diffraction plate 6 and the prism block 5 are parallel to each other. Collimating lens (4) to make it, the LCS (3) acts as an aperture to tighten and widen the light passing through the collimating lens (4), and enters the optical disk (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 disc 1 is partially reflected while passing through the dozen prism blocks 5, and then in a form suitable for the photodiode 10. It consists of sensor lenses (8, 9) to adjust .

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 to the prism block (5) and collimating lens (4), The optical disk 1 is focused by passing through the LCS 3 and 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. An abnormality is formed in the photodiode 10 that converts the incident light after passing through the sensor lenses 8 and 9 into a current, and changes to 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), the diffraction plate (6) is required for this purpose 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 servo is out of focus, 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 has a problem in that the structure is complicated, and in particular, it is difficult to manufacture a component such as an LCS, and a lot of adjustment points are required during assembly.

In view of the foregoing, the present invention provides a hologram pickup module (hereinafter referred to as HPM) capable of simultaneously acting as a photodiode and a laser diode for an optical pickup apparatus having a compatibility between DVD and CD, thereby utilizing the optical pickup apparatus for DVD. The purpose is to enable increased efficiency and productivity.

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

First, as shown in FIG. 3, a 650 nm HPM 105 and a 780 nm HPM 106 which emit a laser and receive reflected light, and a polarizing beam that transmits the light emitted from the HPM A collimator (PBS) 104, a collimating lens 103 which transmits light emitted from the polarizing beam splitter 104 in parallel, and light passing through the collimating lens 103 are focused to focus on the disk 101. Consisting of the objective lens 102.

When the information of the DVD is read on the disk 101 in the above-described state, the optical disk 101 → objective lens 102 → collimation lens 103 → polarization beam splitter 104 → HPM 105 is configured. When reading the information of the CD, the system consists of an optical disk 101, an objective lens 102, a collimating lens 103, a polarizing beam splitter 104, and an HPM 106.

First, in the case of a DVD, the laser emitted from the HPM 105 passes through the polarization beam splitter 104, the collimating lens 103, and the objective lens 102 to focus about 0.8 μm on the optical disk 101. This focus is reflected again and passes through the objective lens 102, the collimating lens 103, and the polarizing beam splitter 104 to enter the photodiode embedded in the HPM 105.

At this time, the servo is operated by devices that are modularized in the HPM 105 itself. Since the servo is designed exclusively for DVD, no offset occurs, and the adjustment process only needs to adjust three beams.

In the case of the CD, when the 650 nm HPM 105 is turned off and the 780 nm HPM 106 is operated, the information on the disc is read through the same process as described above, and the offset is not generated and the adjustment is simple. .

And FIG. 4 is a further embodiment of the present invention in which a laser coupler (205, 206) is installed instead of the HPM (105, 106) as in (a) or the HPM (305) and the laser coupler (306) are selected as in (b). The same performance can be contributed even if installed.

The present invention as described above is an invention 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 (3)

First light emitting means for emitting a laser beam, beam converting means for reflecting the beam generated by the light emitting means in the direction of the optical disc, and a first lens for making the beam radiated through the beam converting means to be a parallel beam And a second lens for condensing light passing through the first lens to focus on the disk, and the light reflected from the optical disk passes through the first lens and the second lens and passes through the beam converting means to provide light. A light emitting means for converting a signal into an electrical signal, the second light emitting means for emitting a laser beam to read only a CD signal, and the beam generated by the light emitting means reflected to the optical disc through the beam converting means. The beam passes through the first lens and the second lens, and the light reflected from the optical disk passes through the first lens and the second lens in the reverse direction, and passes through the beam conversion means to the disk surface. The light of an optical pickup device, characterized in that consists of an optical switching means for converting a signal into an electrical signal according to the received light amount. The optical pickup apparatus of claim 1, wherein the first light emitting unit comprises a hologram pickup module that emits and receives a beam having a wavelength of light of 650 nm. The optical pickup apparatus of claim 2, wherein the first light emitting unit is configured by selecting a hologram pickup module or a coupler.