JPS58169351A - Optical information reading device - Google Patents

Abstract

PURPOSE:To make a device small-sized and inexpensive, by using parts serving also as a reflecting operation and a polarizing operation. CONSTITUTION:Light emitted from a light source 1 passes through polarizing prisms 2, 2', and is polarized and simultaneously is reflected by optical parts 3 having a reflecting film 5 consisting of multilayered film coating of magnesium fluoride, zirconium oxide, etc., provided on the surface of a glass plate 4 placed at 45 deg. to the axis X, and is focused onto a disk 8 by an objective lens 6. Reflected light travels backward, is reflected by the polarizing prisms 2, 2', is made incident to a photodetector 7, and information is read. Since the parts serving also as a reflecting operation and a polarizing operation are used, the device can be made small-sized and inexpensive.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an information reading device that optically reads information from an information recording medium such as a video disc or a digital audio disc.

Conventionally, optical information reading devices, such as optical video
As an optical information reading device for an information reproducing device such as a disc player, there is generally one shown in FIG.

That is, the light beam emitted from the light source 1 is polarized by the grism 2.2.
′), a phase change is given by the wave mourning plate 10 in the latter stage,
Next, the elementary rays reflected at (,'-11) are focused by the objective lens 6 onto an information recording surface of 1 m 1 K on the disk S.

The light emitted from the objective lens 6 is modulated by information recorded on the disk s, and then reflected to become reflected light. This reflected light then rises and passes through the objective lens @ and is reflected <9-1
After being reflected by fI-1, the phase is further changed by wave plate 10, reflected by polarizing prism 2', received by light-receiving element IK, and then converted into an electrical signal, and the signal from the disk. is played. The polarizing prism 2.2' serves as a so-called beam splitter that selectively reflects or transmits incident light depending on the polarization direction of the incident light.

However, in such an electro-optical information reading device, the phase change to change the polarization direction of incident light or reflected light is performed by the polarization action of the wave plate 100, and the reflection action to change the optical path is performed by the reflector 11. I was going. This rounding,
This was expensive because it took up a lot of space to install the optical system components, and even though the entire device had to be replaced with a separate adjustment mechanism, each had its own adjustment mechanism.

The present invention has been made in view of the above-mentioned points, and its purpose is to combine the polarizing action of a corrugated plate and the reflecting action of a reflecting mirror into a single system. We provide an optical information line ML device that can be used to reduce the size and cost of the device by reducing the installation space for optical components and requiring only one adjustment component. be.

The following is a description of some typical embodiments of the IJ110 with reference to the drawings. I will clarify.

First, in the first embodiment shown in FIGS. 2 and 3, 1 is a light source, 1.2' is a polarizing prism disposed in the optical path and serves as an optical means for the irises 1, and 3 is an optical means for the irises 1. A second optical means is placed after the polarizing prism 2 as a means at a specific angle (A depending on the material) with respect to the optical axis The reflective film 5 is formed by a multilayer coating (see FIG. 3), and the multilayer coating is formed by vapor-depositing magnesium fluoride, zirconium oxide, or the like.

is arranged in the optical path between the polarizing prism 2 as the first optical means and the objective lens 6. T is a light receiving element, and Hatake is D111::.

The first embodiment of the present invention has the above-mentioned structure), and the light #
The irradiation light of one glass (for example, a H-laser) is transmitted through a polarizing prism 2゜2' as a first optical means, and then a glass plate placed at, for example, 4S' with respect to the optical axis X. Board 401! ! For example, magnesium fluoride is used as a reflective film S formed by LiK.

A multilayer coating made of zirconium oxide or the like causes a phase change, causing the light to be polarized and reflected at the same time. This reflected light is then focused by the objective lens 6, and is irradiated onto the signal (pit) recorded on the disk 8 and modulated. In this way, the reflected light modulated by the disk 8 is
The light passes through the objective lens again, undergoes a phase change, and is polarized and reflected at the same time by the second optical means S. Then, the reflected light from the reflective film 5 is reflected by the joint surface of the polarizing prisms 2 and 2' serving as the first optical means, and is received by the light receiving element T. This is polarizing prism 2. This is because the junction surface of z' is formed by a polarizing film, and the incident light is selectively reflected or transmitted depending on its polarization direction. Here, since the phase change in the reflective film SK is set to 1/4 wave of the irradiated light, the polarization direction of the reflected light is perpendicular to the polarization direction of the light sealed by the light source 11CM). The reflected optical path is separated from the optical path of the illuminating light. After that, when the light is received by the light-receiving element T, the signal from the disk 8 is converted into an electrical signal, and the information is read.
4IgK shows a second embodiment of the present invention, in which the tit second optical means 3 is formed by using a natural quartz crystal or calculus with respect to the optical crystal axis. The 0-reflection ff1ri', which is formed by providing a reflective surface 5' on the cut-out refracting plate 4' directly within a predetermined O, is formed using a multilayer film coating or a total light reflection surface. The birefringent plate 4' exerts a polarizing effect, and the reflective element S made of a multilayer coating performs a reflective effect.

Furthermore, what is shown in FIG. 1S is a third embodiment of the present invention, and in this embodiment, polarized light is applied to the slope 4# of the polarizing prism 4" to form the second optical fishing hook R3. It is formed by providing a reflective film S consisting of a multi-knit coating having a function. Also in this embodiment, the polarizing frim 4'' serving as the second optical means 3 performs the polarizing action and the reflecting action at the same time.

What is shown in FIG. 6 is a fourth embodiment of the present invention, and in this embodiment, a sloped portion 4 is formed at an angle of approximately 45° with respect to the optical axis XK and is joined to the sloped portion 2m of the polarizing prism 2. #
The second optical means 3 is formed by providing a reflection film S made of a multilayer coating on the front side surface portion 4#B on the other side. In this embodiment, the light from the light source 1 is transmitted through a polarizing prism! , 4
The light passes through the trapezoidal polarizing prism 4'' on the sloped surface 4''B provided on the other side of the trapezoidal polarizing prism 4'' and causes a phase change by the reflective film 5, changing the polarization direction and at the same time being reflected, the optical path is changed. After being changed, the light is focused by an objective lens 6, irradiated onto a disk 8, and modulated on the information recording surface of the disk. After the reflected light from the disk 8 passes through the objective lens 6 again, it is polarized (by nine reflective films provided on each of the trapezoidal polarizing prisms 2) and reflected parallel to the optical axis XK. This reflected light is passed through a polarizing prism 2.
The light is reflected by the bonding surface of #4 and received by the light receiving element T.

As described above, the present invention can exhibit both the polarization effect of a conventional wavelength plate and the reflection effect of a reflective reflector using a single component. As a result, the installation space for optical components can be reduced, and all! Only one part is required, etc.
The device can be made smaller and the cost can be reduced.

[Brief explanation of drawings]

FIG. 1 is an explanatory cross-sectional view showing a conventional optical recording and reproducing device, FIG. 2 is a wR view showing a first embodiment of the present invention, and FIG. The sectional view shown in FIG. 4 is #! of the present invention. Figure S is a cross-sectional view showing the third embodiment of the present invention, and Figure 6 is a cross-sectional view showing the fourth embodiment of the present invention.
FIG. 9 is a cross-sectional view showing an embodiment. 1... Light source, 2.2'...141 optical means, 3
...Song 2 optical means, 4...Glass plate, 4'...
・Birefringence plate, 4#...Polarizing prism, 4''...Polarizing prism, 5...Reflecting film. 3rd @ Figure 4

Claims (3)

[Claims] (1) III optical means that selectively reflects or transmits wrinkled rays depending on the polarization direction of the irradiated light; and a second optical means that reflects at least the rays that have passed through the first optical means. In an optical information reading device including an optical means,
An elementary optical information reading device characterized in that the second optical means has a reflecting effect and a polarizing effect on the light emitted from the light source. (2) The optical information capture function according to claim 1, wherein the second optical means includes a multilayer coating. (3) The multilayer coating is characterized by having a fluoride layer, a fluoride layer, and a dil oxide layer. Destruction. 4) The optical system according to claim 1, wherein the first optical means has a birefringent plate cut at a predetermined angle with respect to the optical crystal axis and a reflective metal. information reading device/