KR19980077500A - CD / DVD combined pickup unit with collimator lens removed - Google Patents

Abstract

The present invention relates to an apparatus for simultaneously reading a DVD (Digital Video Disc) and a CD (Compact-Disc) in an optical pickup apparatus, wherein the data of the CD disc or the DVD disc are stored by removing the collimator lens. By adjusting the focus of the actuator on the information surface, the drive system to adjust the focus of the actuator is simplified, and the number of parts is greatly reduced by not using the collimator lens, thereby reducing material costs, mass production, and stabilizing the system.

Description

CD / DVD combined pickup unit with collimator lens removed

The present invention relates to a device for simultaneously reading a DVD (Digital Video Disc) and a CD (Compact-Disc) in the optical pickup device, in particular the focus (FOCUS) of the actuator to which the objective lens is connected by removing the collimator lens By adjusting the distance, it is possible to detect data on a CD disk or a DVD disk without using a collimator lens.

Conventional optical pickup apparatus for both DVD and CD includes a laser diode (1) for emitting a laser beam, a diffraction grating (2) for receiving a beam emitted from the laser diode (1), and an output from the diffraction grating (2). A beam splitter 3 for receiving a beam and outputting the beam to the collimator lens 4, a collimator lens 4 receiving the beam output from the beam splitter 3, and an output from the collimator lens 4 The optical path modifier 5 receiving the beam, the objective lens 6 receiving the beam output from the optical path modifier 5 and focusing on the data of the disk, and the objective lens 6 reads and reflects the data in the disk. An optical path changer 5 receiving light, a beam splitter 3 receiving light output from the optical path changer 5, a cylindrical lens 7 receiving light output from the beam splitter 3, a cylindrical lens It consists of a photodetector 8 which receives the light output from (7).

Such a conventional apparatus has a laser diode (1) is emitted from the diffraction grating (2) when firing the laser beam, and when the laser diode (1) emits a laser beam, the beam splitter (3) changes direction and passes through the collimator lens (4) in the optical path changer (5) The beam is switched to the objective lens 6 to focus the data on the disk in the objective lens 6, and the light reflected from the disk is input back to the optical path modifier 5 and output to the collimator lens 4, and then collied. When the meta lens 4 receives light from the beam splitter 3 and outputs it to the cylindrical lens 7, when the light input from the cylindrical lens 7 is output to the photo detector 8, the photo detector 8 By analyzing the amount of light received, it is possible to know whether it is accurately positioned at a desired track position and whether the focus state is correct.

In addition, if the track position and the focus are not accurate, a constant current is applied to the tracking and focusing coils in the magnetic circuit part (not shown) to adjust the driving direction in the tracking direction or the focusing direction as much as the error value, so that the correct track is always accurate. The position and percussion state are maintained. At this time, if the disc is a DVD or a CD, the CD disc is operated. When the objective lens 6 is used for the CD, the magnetic lens is operated when the objective lens 6 is used for the DVD. A certain amount of current is applied to the tracking coil of the circuit section so that the objective lens 6 switches from DVD to CD, and the above operation is performed even when the DVD disc is used.

However, the conventional optical pickup device for both DVD and CD as described above has a problem in that the drive system of the actuator in the optical pickup device is complicated by using two objective lenses, and the system is unstable due to the large number of parts using the collimator lens. .

Disclosure of the Invention An object of the present invention is to solve the above-mentioned conventional problems, and in particular, by removing the collimator lens and outputting parallel light as divergent light from the optical path changer to the objective lens so that the disc or the disc of the DVD The present invention provides a CD / DVD combined pickup device that removes a collimator lens that reads data from a CD disc or a DVD disc by using an objective lens by adjusting the focus of the actuator on the information surface in which the data is stored. .

In order to achieve the above object, the present invention removes the collimator lens combined CD / DVD pickup device, the optical path changer is maintained a predetermined distance so that the divergent light output from the beam splitter can be input from the objective lens; It is characterized in that it comprises an actuator for reading the information surface of the CD / DVD by receiving the divergent light output from the optical path changer to adjust the position of the objective lens by a predetermined length.

The CD / DVD combined pickup device which removes the collimator lens of the present invention has a simple driving system for adjusting the focus of the actuator and greatly reduces the number of parts by not using the collimator lens, thereby reducing material cost, mass production, and stabilizing the system. There is.

1 is a block diagram showing the configuration of a conventional DVD and CD combined optical pickup device;

Figure 2 is a block diagram showing the configuration of a CD / DVD combined pickup device with a collimator lens removed according to an embodiment of the present invention.

* Description of the symbols for the main parts of the drawings *

1: laser diode 2: diffraction grating

3: beam splitter 4: collimator lens

5: optical path changer 6: objective lens

7: Cylindrical lens 8: Photodetector

10: objective lens 20: optical path changer

Hereinafter, with reference to the accompanying drawings, the configuration and operation of the embodiment according to the technical idea of the CD / DVD combined pickup device to remove the collimator lens of the present invention in detail as follows.

Example

First, the output terminal of the laser diode 1 and the input terminal of the diffraction grating 2 are connected, and the output terminal of the diffraction grating 2 and the input terminal of the beam splitter 3 are connected, and the output terminal of the beam splitter 3 and the optical path changer are connected. The input terminal of 20 is connected, and the output terminal of the optical path changer and the input terminal of the objective lens 10 are connected.

In addition, the objective lens 10 reads data from the information surface in the disk, receives the reflected light, and connects it to the input terminal of the optical path changer 20 again, and the output terminal of the optical path changer 20 and the input end of the beam splitter 3. An embodiment of the present invention is constructed by connecting the output end of the beam splitter 3 and the input end of the cylindrical lens 7 and the output end of the cylindrical lens 7 and the input end of the photodetector 8.

Therefore, when the beam which is the divergent light emitted from the laser diode 1 is input to the beam splitter 3 through the diffraction grating 2, the beam splitter 3 is diverted by a predetermined length so that the divergent light converges in the objective lens 10. When outputted to the optical path changer 20 and output to the objective lens 10, the beam input from the objective lens 10 is focused on the information surface in the disk to read data, and the reflected light is returned to the optical path modifier 20 again. If the output is output to the beam splitter 3 from the optical path changer 20 and input to the photodetector 8 through the cylindrical lens 7 from the beam splitter 3 according to the amount of light input from the photodetector 8 The disc of the DVD can be found and the actuator of the objective lens 10 can be focused to read out the data on the disc.

As described above, the CD / DVD combined optical pickup device from which the collimator lens of the present invention has been removed has a simple driving system for adjusting the focus of the actuator, and the number of parts is greatly reduced because the collimator lens is not used. The savings and the system is more stable.

Claims (1)

An optical path changer maintaining a predetermined distance to receive divergent light output from the beam splitter from the objective lens; CD / DVD combined light without collimator lens, characterized in that it comprises an actuator that receives the divergent light output from the optical path changer and adjusts the position of the objective lens by a predetermined length to read the information surface of the CD / DVD. Pickup device.