JP3068299U - Optical mirror and optical pickup device - Google Patents

Abstract

(57) [Problem] To provide an optical mirror in which at least one of the inner angles is cut into a square shape having a size other than a right angle so that the front and back surfaces can be easily determined without performing a C-plane cut or the like. Is to do. A beam splitter (1) has a parallelogram-shaped surface, so that the shape when viewed from the back side and the shape when viewed from the front side are reversed left and right. Therefore,
The operator can easily determine the front and back surfaces of the beam splitter 1 from the difference in shape. In addition, it is possible to prevent a worker from mishandling the front and back surfaces of the beam splitter 1 when assembling the optical pickup device.

Description

[Detailed description of the invention] [Technical field to which the invention belongs]

 The present invention relates to an optical mirror having one surface coated with an optical film that enhances the reflectance or transmittance of light of a specific wavelength, and an optical pickup device using the optical mirror.

[Prior art]

 Conventionally, there has been an optical pickup device as a mechanism for reading data recorded on an optical recording medium such as a CD or a DVD. A conventional general optical pickup device irradiates an optical recording medium 35 with light (laser light) having a specific wavelength output from a semiconductor laser 31 bent at approximately 90 degrees by a beam splitter 32 as shown in FIG. Met. Various techniques for mounting the beam splitter 32 in the optical pickup device are proposed in Japanese Utility Model Laid-Open Nos. 2-135924, 5-27825, 8-10851, and the like. Reference numeral 33 shown in FIG. 7 is an objective lens for narrowing a laser beam applied to the optical recording medium 35, and reference numeral 34 is a photodetector for detecting reflected light from the optical recording medium 35. The photodetector 34 is disposed on the back of the beam splitter 32 (on the opposite side of the optical recording medium 35), and detects the light reflected from the optical recording medium 35 to convert the data recorded on the optical recording medium 35. read.

[Problems to be solved by the invention]

 By the way, in order to efficiently irradiate the laser beam output from the semiconductor laser 31 to the optical recording medium 35, the beam splitter 32 is provided with a reflective film on its surface to increase the reflectance of the laser beam having the wavelength output from the semiconductor laser 31. Coated. Therefore, the beam splitter 32 has front and rear surfaces, and the front and rear surfaces of the beam splitter 32 must be assembled without mistake when assembling the optical pickup device. However, the conventional beam splitter 32, which is cut into a rectangular shape as shown in FIG. 8 (A), requires an operator who assembles the optical pickup device to visually judge the surface on which the reflective film is coated. There is a problem that the front and back surfaces of the splitter 32 are easily mistaken. Therefore, as shown in FIG. 8B, by making a C-plane cut 32a on the side of the beam splitter 32 coated with the reflective film, the operator can easily determine the front and back surfaces of the beam splitter 32. However, since a step of applying a C-plane cut is required in the manufacturing process of the beam splitter 32, the production efficiency of the beam splitter 32 is reduced and the production cost is increased. was there. The beam splitter 32 is cut out in a state where a plurality of glass plates of an appropriate size are stacked. However, the processing for performing the C-plane cutting cannot be performed in a state where a plurality of glass plates are stacked. The process of performing the C-plane cut itself was a time-consuming process. In addition, a beam splitter has been proposed in which the corners are notched in place of the C-plane cut so that the front and back sides can be easily determined (Japanese Patent Application Laid-Open No. 5-273403). There is a problem that the production efficiency is lowered due to the necessity of the process, and the production cost is increased. The purpose of this invention is to provide an optical mirror that can easily determine the front and back surfaces without cutting the C-plane by cutting at least one of the inner angles into a square shape that is not a right angle. Is to do. Another object of the present invention is to provide an optical pickup device in which the front and back surfaces of the optical mirror can be prevented from being erroneously assembled by applying the optical mirror.

[Means for Solving the Problems]

 The optical mirror of the present invention has the following configuration in order to solve the above problem. (1) In an optical mirror having a square surface and an optical film on one surface on which an optical film for increasing the reflectance or transmittance of light of a specific wavelength is deposited, at least one of the inner angles is not a right angle. (2) The surface shape is a parallelogram. The optical pickup device of the present invention has the following configuration. (3) a light source for outputting a laser beam of a specific wavelength, an optical path for guiding the laser beam output from the light source to an optical recording medium such as a CD or a DVD, and reflection from the optical recording medium irradiated with the laser beam An optical pickup device comprising: a light detection unit that detects light; and the optical mirror according to claim 1 or 2 is arranged in the optical path. (4) The optical mirror is mounted by being inserted into a mounting portion having a recess having substantially the same shape as the outer shape. In the optical mirror having the above configuration, since the shape is not a rectangle or a square, the shape when viewed from the side on which the optical film is deposited is different from the shape when viewed from the opposite side. Therefore, the front and back surfaces of the optical mirror (the surface on which the optical film is deposited) can be easily determined from the difference in shape. In addition, since the shape of the mounting portion of the optical mirror in the optical pickup device is substantially the same as that of the optical mirror, the optical mirror cannot be mounted on the mounting portion if the front and back surfaces of the optical mirror are wrong. Absent.). Therefore, it is possible to prevent a waste of the assembling work of assembling the optical mirror with the front and back surfaces wrongly.

[Embodiment of the invention]

 FIG. 1 is a diagram showing an appearance of a beam splitter according to an embodiment of the present invention. The beam splitter 1 of this embodiment has a parallelogram shape as shown in the figure. However, each interior angle is not a right angle (not a rectangle or square). The beam splitter 1 has a reflective film 2 (optical film) deposited on a surface indicated by hatching in FIG. FIG. 2A is a plan view as seen from the surface side (front surface side) where the reflective film is deposited, and FIG. 2B is the surface side (back surface side) where the reflective film is not deposited. It is a top view when seen from. As shown in FIG. 2, the shape of the beam splitter 1 when viewed from the front side (the side on which the reflective film 2 is deposited) and the shape when viewed from the back side appear to be left and right inverted shapes. . Therefore, since the operator can easily determine the front and back surfaces of the beam splitter 1 from the difference in shape, the operator may mistakenly handle the front and back surfaces of the beam splitter 1 when assembling the optical pickup device. Can be suppressed. In addition, in the case of the beam splitter 1 having the above-described shape, a plurality of glass plates 5 can be cut out linearly as shown by a broken line in FIG. Nor. Further, since the C-plane cut for judging the front and back surfaces is not performed unlike the related art, the production cost does not increase. In the above embodiment, the shape of the beam splitter 1 is a parallelogram. However, as shown in FIG. 4, a right and left asymmetric trapezoid may be used. In the above description, the embodiment of the present invention has been described by taking as an example the beam splitter 1 in which a reflective film is deposited on one surface. However, the present invention is applied to an optical mirror in which a transmissive film is deposited instead of a reflective film. Even when applied, the same effect is achieved. FIG. 5 is a diagram showing a configuration of an optical pickup device to which the above-described beam splitter is applied. In the figure, 11 is a semiconductor laser, 12 is a mounting portion for mounting the beam splitter 1, 13 is an objective lens for narrowing the laser beam output from the semiconductor laser 11, and 14 is reflection from an optical recording medium 15 such as a CD or DVD. It is a photo detector that detects light. The optical pickup device of this embodiment also has a configuration in which the laser beam output from the semiconductor laser 11 is bent by approximately 90 degrees by the beam splitter 1, squeezed by the objective lens 13, and irradiated onto the optical recording medium 15. Light reflected from the optical recording medium 15 passes through the beam splitter 1 and is detected by the photodetector 14. The output of the photodetector 14 is input to a controller (not shown), and the controller performs processing such as reproducing data recorded on the optical recording medium 15 based on the output of the photodetector 14. The mounting portion 12 applied to the optical pickup device of this embodiment has a parallelogram-shaped concave portion 12a substantially the same as the outer shape of the beam splitter 1, as shown in FIG. For this reason, as shown in FIG. 6B, if the beam splitter 1 is correctly oriented with respect to the mounting portion 12, the beam splitter 1 can be inserted into the concave portion 12a, but the beam splitter 1 is oriented in the opposite direction. If there is, as shown in FIG. 6C, the corner of the beam splitter 1 hits the concave portion 12a, and the beam splitter 1 cannot be inserted into the concave portion 12a. That is, the beam splitter 1 cannot be physically mounted even if the front and rear surfaces are mounted in the wrong direction. Therefore, it is possible to reliably prevent the beam splitter 1 from being mounted in the wrong direction in the assembly process of the optical pickup device. In this manner, in the optical pickup device of this embodiment, the beam splitter 1 is not mounted in the opposite direction during assembly (it cannot be physically mounted), so that the assembling work can be performed efficiently. In addition, waste in assembly work can be suppressed, and production costs can be reduced.

[Effect of the invention]

 As described above, according to the present invention, the surface on which the optical film is deposited can be easily determined from the shape without performing the C-plane cut, so that the production cost can be suppressed. Also, since the shape is a parallelogram, it can be cut out linearly from a glass plate of an appropriate size, so that the production efficiency does not decrease. Further, in the optical pickup device to which the optical mirror according to the present invention is applied, the optical mirror is not mounted in the opposite direction.

[Brief description of the drawings]

FIG. 1 is a diagram showing an appearance of a beam splitter according to an embodiment of the present invention.

FIG. 2 is a plan view of a beam splitter according to an embodiment of the present invention.

FIG. 3 is a diagram showing a beam splitter cutting method according to an embodiment of the present invention.

FIG. 4 is a plan view of a beam splitter according to another embodiment of the present invention.

FIG. 5 is a diagram showing a configuration of an optical pickup device according to an embodiment of the present invention.

FIG. 6 is a diagram showing a mounting portion applied to the optical pickup device according to the embodiment of the present invention.

FIG. 7 is a diagram showing a configuration of a conventional optical pickup device.

FIG. 8 is a diagram showing an appearance of a conventional beam splitter.

[Explanation of symbols]

 1-beam splitter 2-reflection film 11-semiconductor laser 12-mounting part 12a-recess 13-objective lens 14-photodetector 15-optical recording medium

Claims (4)

[Utility model registration claims] 1. An optical mirror having a quadrangular surface and an optical film on one surface on which an optical film for enhancing the reflectance or transmittance of light of a specific wavelength is deposited, wherein at least one of the inner angles is not a right angle. mirror. 2. The optical mirror according to claim 1, wherein the surface shape is a parallelogram. 3. A light source for outputting a laser beam having a specific wavelength, an optical path for guiding the laser beam output from the light source to an optical recording medium such as a CD or a DVD, and the optical recording medium irradiated with the laser beam. An optical pickup device comprising: a light detecting unit that detects reflected light of the optical mirror. An optical pickup device, wherein the optical mirror according to claim 1 or 2 is arranged in the optical path. 4. The optical pickup device according to claim 3, wherein the optical mirror is mounted on a mounting portion having a recess having substantially the same shape as the outer shape of the optical mirror.