JPH01276441A - Optical head - Google Patents

Abstract

PURPOSE:To continuously reproduce two diskes almost without an interrupting time by providing optical systems for upper side and lower side disk, which irradiates the upper and lower disks with an optical beam, in the middle of the two optical disks, which are arranged upward and downward with being revolvable. CONSTITUTION:An optical head 10 moves in an arrow (a) direction in the middle of upper and lower disks 2A and 2 and reproduces the lower side disk 2 and upper side disk 2A. The optical beam outgoing from a light source 11 is divided into two beams by a beam splitter (BS)12. The optical beam to transmit through the BS12 is reflected by a mirror 13, transmitted through a BS14 and condensed by an objective lens 5 and a spot is formed on the signal surface of the lower side disk 2. The reflected light of the beam goes to a reverse direction. Then, the light is reflected by the BS14 and incoming to an optical detector 16 and signal detection is executed. On the other hand, the optical beam to be reflected by the BS12 is transmitted through a BS17 and condensed by an objective lens 18 and an optical spot is formed on the signal surface of the upper side disk 2A. The reflected light of the beam is reflected by the BS17 and incoming to an optical detector 19 and signal detection is executed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an optical head in an optical disk device that optically reproduces information or records and reproduces information.

・[Conventional technology] FIG. 2 shows an example of the configuration of a conventional optical head 1. As shown in FIG.

In the figure, 2 indicates an optical disc (hereinafter referred to as a disc) placed inside the optical disc device.

As shown by the arrow, a light beam parallel to the disk 2 emitted from the light source 3 is reflected downward at right angles by the mirror 4, transmitted through the beam splitter 5, and condensed by the objective lens 6, and is directed to the signal surface of the disk 2. A light spot is formed on the disc 2, and the returned light is reflected in the right angle direction by the beam splitter 5 and enters the photodetector 7, where signal detection is performed.

As shown in the figure, the conventional optical head 1 has only one objective lens and is configured to emit a signal detection light beam in only one direction.

[Problem to be solved by the invention] There is a strong demand for multifunctionality in optical disc devices, but
With the conventional optical head 1 described above, special playback or the like in which two disks are played simultaneously cannot be realized. Furthermore, an automatic disk exchange mechanism is required for continuous playback of two disks, and some interruption time is unavoidable.

The present invention was made in view of the above circumstances, and it is possible to simultaneously reproduce the contents of two discs, and
To obtain an optical head capable of continuously reproducing two discs without replacing the discs and almost without interruption.

[Means for Solving the Problems] An optical head of the present invention that solves the above problems has two optical disks rotatably arranged parallel to each other and spaced apart vertically inside an optical disk device. It is characterized by comprising a lower disk optical system that is provided in the middle and that irradiates a light beam toward the lower optical disk, and an upper disk optical system that irradiates a light beam toward the upper optical disk. .

[Function] According to the optical head having the above configuration, it is possible to irradiate the upper and lower two discs with a light beam for reading signals independently, and it is possible to play back the two discs at the same time. Become. Therefore, special playback that outputs the contents of two discs from one output device, or two
Individual playback that outputs to two output devices independently, or plays two discs without changing discs, and
It becomes possible to play continuously without any interruption.

[Example code] An embodiment of the present invention will be described below with reference to FIG.

In the figure, the optical head 10 is located between two optical disks 2 and 2A that are rotatably arranged inside an optical disk device with a vertical interval between them, in a feeding direction parallel to the disk surface (in the direction of arrow (A)). It is movably installed. This optical head 10 has one light source 11, and a separating prism 12 for separating the light beam from the light source 11 into a light beam directed to the lower disk 2 and a light beam directed to the upper disk 2A. have. And this separation prism 12
An optical system for the lower disk 2 that utilizes the light beam transmitted through the lower disk 2, that is, an optical system 20 for the lower disk consisting of a mirror 13, a beam splitter 14, an objective lens 15, and a photodetector 16, and the separation prism. An optical system 21 for the upper disk 2A that utilizes the light beam reflected upward at a right angle by the upper disk 12, that is, an optical system 21 for the upper disk consisting of a beam splitter 17, an objective lens 18, and a photodetector 19.
It is equipped with two optical systems. Note that the configuration shown in FIG. 1 is shown in a simplified manner, and does not take into account focusing error detection, tracking error detection, and the like.

Next, the operation will be explained.

The optical head 10 moves in the optical head feeding direction parallel to the disks 2, 2A (in the direction of arrow (A)) between the upper and lower disks 2, 2A to reproduce the lower disk 2 and the upper disk 2A. I do. That is, a part of the light beam emitted from the light source 11 passes through the separating prism 12, is reflected downward at right angles by the mirror 13, passes through the beam splitter 14, is condensed by the objective lens 15, and is directed downward. A light spot is formed on the signal surface of the disk 2, and the return light reflected from the disk signal surface is reflected by the beam splitter 14 in the right direction in the figure at right angles and enters the photodetector 16. Signal detection is performed.

On the other hand, a part of the light beam from the light source 11 is reflected upward at right angles by the separating prism 12, and the beam splitter 1
7 and is focused by the objective lens 18 to form a light spot on the signal surface of the upper disk 2A, and the return light reflected from the disk signal surface is reflected by the beam splitter 17 in the right direction in the figure at right angles. The light enters the photodetector 19, and signal detection is performed by the photodetector 19.

The signals of each disk 2.2A detected by the two photodetectors 16.19 are sent to a signal processing circuit and output to an output device. The output device is, for example, a speaker when the disc is an audio disc, and a display when the disc is a video disc.

Various methods can be considered for outputting on the output device.8 For example, the contents of two discs 2.2A may be played back on the same output device, such as special playback such as picture-in-picture, or , individual playback, etc., in which the contents of two discs are individually and simultaneously output to two output devices, can be considered. Furthermore, continuous playback of two discs is also conceivable. In this case, continuous playback is possible with two discs in place, and there is no need to replace the discs, so continuous playback without a disc replacement device is realized.
In addition, continuous playback is possible with almost no interruptions, such as when playing back within a single disc.

Note that for the optical components that make up the lower disk optical system and the upper disk optical system, it is necessary to provide at least separate objective lenses, but other optical components such as beam splitters and photodetectors may or may not be used together. It's not possible. Conversely, it is also possible to provide two separate optical systems, including the light source, from the light source to the objective lens and photodetector.

In addition, the structure of the optical disk device side requires at least two
It is sufficient that the optical disks are rotatably arranged parallel to each other and vertically spaced apart from each other.

In this case, the two disks are not limited to being arranged concentrically with each other, but the centers may be shifted by, for example, the radius of the disks.

In this case, it is also possible to further increase the interruption time during continuous playback of two discs to vLm.

Furthermore, the optical head of the present invention is not limited to playback of audio discs or video discs, but can also be applied to playback of optical discs as optical memories.

[Effects of the Invention] As explained above, according to the present invention, there is provided an optical system for a lower disc that irradiates a light beam toward a lower optical disc;
Since it is equipped with an optical system for the upper disc that irradiates a light beam toward the upper optical disc, it is possible to play two optical discs in parallel, and the contents of the two discs can be played from one output device. It is possible to perform special playback with output, individual playback with simultaneous output to two output devices individually, or continuous playback of two discs without changing discs and, in most cases, with no interruptions. be done.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an optical head showing an embodiment of the present invention, and FIG. 2 is a block diagram of a conventional optical head. 2.2A...Optical disk, 11...Light source, 12...
・Separation prism, 13...Mirror, 14.17...
- Beam splitter, 15.18... Objective lens, 16.19... Photodetector, 20... Optical system for lower disk, 21... Optical system for upper disk.

Claims (1)

[Claims] A lower disk drive is installed between two optical disks that are rotatably arranged parallel to each other and spaced apart vertically inside an optical disk device, and irradiates a light beam toward the lower optical disk. An optical head comprising: an optical system; and an upper disk optical system that irradiates a light beam toward an upper optical disk.