JPS61144734A - Optical disk device - Google Patents

Abstract

PURPOSE:To obtain an inexpensive, high-reliability optical disk device by reproducing signals of plural tracks recorded on a medium physically by a light emitting element array and a photodetecting element. CONSTITUTION:The photodetecting element 1 is arranged at the focus of an optical lens 2. An optical disk 3 rotates on a rotating shaft 5 and is provided with tracks concentrically with the shaft, and information is recorded on the tracks by utilizing variation of optical properties of the material of the disk. An opaque disk 7 having holes 8 bored with laser light is also usable. The light emitting element array 4 consists of light emitting elements in series at equal intervals and the respective light emitting element emit light at right angles to the disk 3(7); the light is passed through a transparent part of the disk 3 or a hole 8 of the disk 7, converged through the optical lens 3, and converted by the photodetecting element 1 into an electric signal. Consequently, one light emitting element in the light emitting element 4 illuminates and the signal on the track corresponding to the track is reproduced as the electric signal.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a recording/reproducing device using light, and particularly to a small-sized,
The present invention relates to a system suitable for low-cost optical disc devices.

[Background of the invention]

Typical optical disc devices use a laser as a light source and also require the use of servos for tracking and focusing, making it difficult to reduce costs and making them vulnerable to mechanical shock. Ta.

Therefore, it has been desired to develop a recording and reproducing method for optical disks that does not require a complicated mechanism.

As a concept close to the present invention, Japanese Patent Application Laid-Open No. 58-97142
No. 1, but it did not take into account the case where the distance between the busy medium and the detection device, such as non-contact optical disks, is large.

[Purpose of the invention]

An object of the present invention is to provide a novel optical disc playback method that eliminates the drawbacks of the prior art described above. Allocate concentric tracks to each element array.

Information is reproduced depending on whether the light emitted from the light emitting element passes through the disk or not. 5.) Rack selection is performed by causing the light emitting element assigned to that track to emit light. The light emitted from the light emitting element is collected by a light receiving sensor by a condensing lens and detected.

[Embodiments of the invention]

FIG. 1 shows a reproduction optical system of an optical disc device.

A light receiving element 1 is placed at the focal point of an optical lens 2.

The optical disc 3 rotates around a rotating shaft 5.

As shown in FIG. 2, an optical disk is provided with concentric tracks around an axis, and information is recorded along the tracks by changing the optical properties of the material of the disk.

FIG. 2 shows a hole 8 made in an opaque disk 7 using a laser.

In the light emitting element array 4, light emitting elements using semiconductor lasers or the like are arranged in series at equal intervals, and each light emitting element emits light perpendicularly to the disk. Light emitted from the light emitting elements indicated by black dots in the array 4 reaches the optical disk through an optical path indicated by a line. Since the optical disk is rotating, light can pass through it if the disk on the optical path is transparent. Also, if it is opaque, it cannot be passed through.

The light that has passed through the disk is focused by an optical lens 2 and converted into an electrical signal by a light receiving element 1.

In this way, by causing one light emitting element in the light emitting element array to emit light, it is possible to reproduce the signal on the track corresponding to that element as an electrical signal.

Another idea is to use the light receiving element 1 as a light emitting element and the light emitting element array 4 as a light receiving element array. However, in this case, the holes made in the tracks on the disk create a draft, so signals recorded on other tracks may be mixed in, resulting in 87.
N gets worse.

The structure of the light emitting element array is shown in FIG. A light emitting element array has light emitting elements and circuits for operating them provided on the same substrate. By turning on a specific transistor in the driver 11 using the address switch 9 and causing current to flow through the light emitting element 12, the specific light emitting element can be caused to emit light.

The light emitting element must emit light of a wavelength that can be detected by the light receiving element. Further, it is necessary to focus the light using the microlens 6 so that the light does not leak into adjacent tracks.

FIG. 4 shows an example of an optical disc device. The light emitted from the light emitting element array 15 is transmitted to the optical disk 15 which rotates around the axis.
After passing through the optical lens 16, the direction is changed by a mirror attached at an angle of 45° to the Dinuk surface.
After the light is focused, the light is converted into an electrical signal by the light receiving element 17.

Since the optical lens only needs to focus light parallel to the disk surface, a two-dimensional lens as shown in the figure can be used.

By using such lenses and mirrors, the device can be made smaller and thinner.

If the distance between the light emitting elements and the track width are 20 μm, and the track diameter of the optical disk is 4 crn to 5 cfn, and information is recorded with or without a hole with a diameter of 2 μm, one travku will produce approximately 7.
．． With 8 bytes and 500 tracks, a capacity of approximately 3.9 Mbytes can be recorded. Furthermore, even when the track width is small, tracking can be performed by controlling the position of the light emitting element array.

[Effect of the invention]

A feature of the present invention is that it does not have any moving parts other than the disk rotation system. This makes it possible to reduce costs and improve reliability. Also, no complicated servo system is required.

Since track selection is performed by selecting only one of the light emitting elements, data can be accessed much faster than in a system in which a track is selected by mechanically moving the head. As described in 5 above, it is possible to process a large amount of data within a short time.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of a reproducing optical system of an optical disc device according to an embodiment of the present invention, FIG. 2 is a structural diagram of a light emitting element array, and FIG. 5 is an illustration of a miniaturized optical disc device using mirrors and two-dimensional lenses. Structural diagram, FIG. 4 is a structural diagram of an optical disc. DESCRIPTION OF SYMBOLS 1... Light receiving element, 2... Condensing lens, 5... Optical disk, 4... Light emitting element play, 5... Disk rotation axis, 6... Microlens, 7... Optical disk,
8... Hole, 9... Address switch, 10... Power supply, 11... Driver, 12... Light emitting element, 15...
... Optical disk, 14... Mirror, 15... Light emitting element, 16... Two-dimensional lens, 17... Light receiving element. f-・, f) Agent Akiyoshi Takahashi - Figure 7 Figure 2 (cL)

Claims (1)

[Claims] 1. An optical disc device characterized in that signals of a plurality of tracks physically recorded on a medium are reproduced by a light emitting element array and a light receiving element.