JP2007179621A - Optical pickup - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical pickup improved in the fixing of a polarized beam splitter and optical characteristics. <P>SOLUTION: A longitudinal section triangular reference room 8 equipped with longitudinal and horizontal reference surfaces 8a and 8b facing the longitudinal and horizontal end surfaces 2b and 2c of one triangle prism 2A, and a pair of left and right triangular reference surfaces 8c and 8d facing both triangle side faces 2d and 2e of one triangle prism 2A are formed in a pickup main body 1, a communication room 9 communicated with the reference room 8 is formed in the pickup main body 1, a pair of left and right slope step surfaces 11 and 12 are formed between the inner surfaces 9c and 9d communicated with both triangular surfaces 8c and 8d of the reference room 8, one triangle prism 2A is inserted into the reference room 8, the other triangle prism 2B is inserted into the communication room 9, the slopes 2a of both triangle prisms 2A and 2B abut on each other, and adhesives are applied between the triangle side faces 2d of the other triangle prism 2B and the slope step surfaces 11 and 12 adjacent thereto. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to an optical pickup used in a disk device (DVD player, DVD recorder, etc.), and in particular, improves the fixing and optical characteristics of a polarizing beam splitter.

An example of the optical pickup is shown in FIG. This is because a polarizing beam splitter PBS is disposed in a pickup body 1 made of synthetic resin, and an objective lens OL, a collimating lens QWP, and a photodiode PD are disposed at both ends of the pickup body 1 with the polarizing beam splitter PBS interposed therebetween. The semiconductor laser LD is disposed on the side surface of the pickup body 1, and laser light is projected from the semiconductor laser LD onto the optical disc D via the polarization beam splitter PBS, the collimating lens QWP, and the objective lens OL, and the reflected light thereof. Is received by the photodiode PD via the polarization beam splitter PBS,
The information recorded on the optical disc D is read.

Conventionally, as shown in FIG. 9, the polarizing beam splitter PBS has two triangular surfaces each having an inclined surface 2a, a vertical end surface 2b and a horizontal end surface 2c facing the inclined surface 2a, and a pair of left and right triangular side surfaces 2d and 2e. The prisms 2A and 2B are formed by bonding the inclined surfaces 2a with an optical adhesive 3.

According to the above configuration, since the refractive indexes of light of the triangular prisms 2A and 2B and the optical adhesive 3 are different, there is a difficulty that the optical characteristics (AS aberration) of the projection light and the reflected light from the semiconductor laser LD are deteriorated. is there.

There exists what was described in patent document 1 as a technique which eliminates the said difficulty. This is shown in FIG.
As shown in FIG. 2, the inclined surface 2a of each triangular prism 2A, 2B is washed with an alkaline solution,
After removing the alkaline solution by washing with ultrapure water W, as shown in FIG.
Ultra-pure water is applied to the two, and the inclined surfaces 2a are brought into contact with each other so that the triangular prisms 2A and 2B are aligned. Subsequently, the triangular prisms 2A and 2B are heated (50 ° C. to 500 ° C.) to evaporate the ultrapure water on the inclined surface 2a, and as shown in FIG. An ultraviolet curable adhesive 6 is applied to the square chamfered shape portion 5 formed between both ends of the glass, and the adhesive 6 is cured by irradiating ultraviolet rays, thereby connecting the both triangular prisms 2A and 2B to the polarizing beam splitter. PBS is formed.
JP-A-8-278407

In the above conventional configuration, as shown in FIG.
F4 is generated toward both ends of the triangular prisms 2A and 2B, and the inclined surfaces 2a of the triangular prisms 2A and 2B are brought into close contact with each other by the tensile forces F1 to F4. Since the direction in which F4 acts is dispersed and different, and the magnitude of each of the tensile forces F1 to F4 may be different due to uneven application amount of the adhesive 6, the component force f along the inclined surface 2a And the triangular force 2B may cause the triangular prisms 2A and 2B to slide sideways in the opposite direction due to the component force f. If the side slip occurs, the intermolecular force between the inclined surfaces 2a decreases. As a result, a gap may be formed between the inclined surfaces 2a to form an air layer. Since the air layer and the triangular prisms 2A and 2B have different light refractive indexes, projection light and reflection from the semiconductor laser LD are generated. Optical properties of light AS aberration) it will be the worse.

In addition, since a means for fixing the polarization beam splitter PBS to the pickup body 1 is required separately, the fixing structure becomes complicated and the manufacturing cost is high.

An object of the present invention is to provide an optical pickup which improves the fixing and optical characteristics of a polarizing beam splitter in view of the above-described conventional drawbacks.

In order to achieve the above object, the invention according to claim 1 is characterized in that the inclined surfaces of two triangular prisms each having an inclined surface, a vertical end surface and a horizontal end surface opposed to the inclined surface, and a pair of right and left triangular side surfaces are provided. A polarizing beam splitter formed by connecting with an adhesive is disposed in the pickup body, and a laser beam is projected onto the disk through the polarizing beam splitter, and the reflected light is received through the polarizing beam splitter. In the optical pickup adapted to read the information recorded on the disc, the vertical reference facing the vertical end surface and the horizontal end surface of the one triangular prism is eliminated by eliminating the adhesive that connects the inclined surfaces of the triangular prisms. The pick-up main body has a triangular reference chamber having a vertical cross section having a plane and a horizontal reference plane and a pair of left and right triangular reference planes facing both triangular side faces. And a communication chamber communicating with the reference chamber is formed in the pickup body, and a pair of left and right step surfaces are formed between both triangular reference surfaces of the reference chamber and the inner surface of the communication chamber. A plurality of guide rails for guiding both triangular prisms toward the reference chamber are integrally projected on the inner surface of the chamber at a predetermined interval, and one triangular prism is placed along the plurality of guide rails in the reference chamber. The other triangular prism is inserted into the communication chamber, the inclined surfaces of both triangular prisms are brought into contact with each other, and each triangular side surface of the other triangular prism is bonded to each adjacent step surface. It is characterized by applying an agent.

The invention according to claim 2 is a polarization formed by opposing the inclined surfaces of two triangular prisms each having an inclined surface, a vertical end surface facing the inclined surface, a horizontal end surface, and a pair of left and right triangular side surfaces. A beam splitter is arranged in the pickup body, and laser light is projected onto the disk via the polarization beam splitter, and the reflected light is received via the polarization beam splitter, so that the information recorded on the disk is received. In the optical pickup configured to read, a longitudinal reference surface having a longitudinal reference surface facing the longitudinal end surface and the lateral end surface of the one triangular prism and a lateral reference surface and a pair of left and right triangular reference surfaces facing both triangular side surfaces are triangular. A reference chamber is formed in the pickup body, and a communication chamber communicating with the reference chamber is formed in the pickup body. A pair of left and right step surfaces are formed between the triangular reference surfaces of the chamber and the inner surface of the communication chamber. One triangular prism is inserted into the reference chamber and the other triangular prism is inserted into the communication chamber. The inclined surfaces of both triangular prisms are brought into contact with each other, and an adhesive is applied between each triangular side surface of the other triangular prism and each step surface adjacent thereto.

According to a third aspect of the present invention, in the second aspect of the present invention, a plurality of guide rails for feeding the triangular prisms toward the reference chamber are integrally projected on the inner surface of the communication chamber at a predetermined interval. It is characterized by being installed.

The invention according to claim 1 corresponds to one embodiment (see FIGS. 1 to 7), and according to this, one triangular prism inserted into the reference chamber and the other inserted into the communication chamber. Tensile force generated by shrinkage caused by curing of the adhesive by applying an adhesive between each triangular side surface of the other triangular prism and each step surface adjacent to each other, with the inclined surfaces of the triangular prism abutting each other. The two triangular prisms are connected to each other, and the tensile force is concentrated toward one triangular prism via the other triangular prism, so the intermolecular force between the inclined surfaces of both triangular prisms Works strongly, and the inclined surfaces are firmly adhered to each other, so that both the triangular prisms can be reliably integrated, so that the projection light and the reflected light that pass through the polarizing beam splitter composed of the both triangular prisms can be obtained. It is possible to improve the optical properties (AS).

Further, by simply fixing the other triangular prism to the pickup main body with an adhesive, the other triangular prism is also fixed to the pickup main body. The connection between the two triangular prisms and the fixing to the pickup main body 2 Two operations can be performed simultaneously by one adhesive application operation, so that the work efficiency is high and the production cost can be reduced.

Further, the other triangular prism can be smoothly fed to one triangular prism in the reference chamber along each guide rail integrally projecting on the inner surface of the communication chamber, and the inclined surfaces of both triangular prisms can be precisely opposed to each other. it can.

The invention according to claim 2 corresponds to the basic form, and according to this, the inclined surfaces of one triangular prism inserted into the reference chamber and the other triangular prism inserted into the communication chamber are brought into contact with each other. Applying an adhesive between each triangular side of the other triangular prism and each adjacent stepped surface, and connecting both triangular prisms by the tensile force generated by the shrinkage caused by the hardening of the adhesive Since the tensile force is concentrated toward one triangular prism via the other triangular prism, the intermolecular force between the inclined surfaces of both triangular prisms works strongly, and the inclined surfaces are The triangular prisms can be securely integrated with each other, and the optical characteristics (AS) of projection light and reflected light passing through the polarizing beam splitter made up of the triangular prisms can be thereby improved. It can be good.

Further, by simply fixing the other triangular prism to the pickup main body with an adhesive, the other triangular prism is also fixed to the pickup main body. The connection between the two triangular prisms and the fixing to the pickup main body 2 Two operations can be performed simultaneously by one adhesive application operation, so that the work efficiency is high and the production cost can be reduced.

According to the third aspect of the present invention, the other triangular prism is smoothly fed to one triangular prism in the reference chamber along each guide rail integrally projecting on the inner surface of the communication chamber, and the inclination of both triangular prisms The faces can be made to face each other precisely.

FIGS. 1-5 shows the principal part of the optical pick-up which is one Embodiment of this invention,
A reference chamber 8 for housing one triangular prism 2A and a communication chamber 9 for housing the other triangular prism 2B are formed in the pickup body 1 in a state where they are in communication with each other. Components other than those described above are denoted by the same reference numerals as those shown in FIGS. 8 to 11 and description thereof is omitted.

As shown in FIGS. 4 and 5, the reference chamber 8 includes a vertical reference surface 8a and a horizontal reference surface 8b facing the vertical end surface 2b and the horizontal end surface 2c of one triangular prism 2A, and both triangular side surfaces 2d and 2e. It has a pair of left and right triangular reference surfaces 8c and 8d facing each other, and its width a1, length b1 and height c
1 is the width a, length b and height c of one triangular prism 2A (and the other triangular prism 2B).
Are set to be the same as or slightly larger than each other, and are formed in a triangular cross section (see FIG. 1).
Reference numeral 10 denotes a light passage hole.

As shown in FIGS. 1 to 4, the communication chamber 9 has four inner surfaces 9 a to 9 d surrounding the reference chamber 8.
And has a rectangular opening 9A concentric with the reference chamber 8, and the width a2 and length b2 of the opening 9A are set slightly larger than the width a1 and length b1 of the reference chamber 8. Thus, the inclined step surfaces 11 and 12 are formed between the left and right inner surfaces 9c and 9d of the communication chamber 9 and the triangular reference surfaces 8c and 8d of the reference chamber 8 along the triangular reference surfaces 8c and 8d. A flat stepped surface 13 is formed between the front and rear inner surfaces 9a, 9b of the communication chamber 9 and the vertical reference surface 8a and the horizontal reference surface 8b of the reference chamber 8 along the reference surfaces 8a, 8b. , 14 are formed.

As shown in FIGS. 1 to 4, a plurality of guide rails 15 for feeding the triangular prisms 2 </ b> A and 2 </ b> B toward the reference chamber 8 are provided from the opening 9 </ b> A to the inner surfaces 9 a to 9 d of the communication chamber 9. ~
14 projecting integrally with a predetermined interval up to 14, and the prism facing surface 15a of each guide rail 15 thereof.
Is formed so as to be flush with the outer peripheral edges of the reference surfaces 8a to 8d of the reference chamber 8.
The triangular prisms 2A and 2B can be smoothly fed toward the reference chamber 8 along the inclined surface 2a so that the inclined surfaces 2a of the triangular prisms 2A and 2B can be precisely opposed to each other (see FIG. 1).

The procedure for fixing the polarization beam splitter PBS will be described. As shown in FIG. 6A, one side of the pickup main body 1 is tilted so that the inclined step surfaces 11 and 12 are positioned substantially horizontally. The triangular prism 2A is inserted into the reference chamber 8 through the communication chamber 9,
By inserting the other triangular prism 2B into the communication chamber 9 and feeding it along the guide rail 15, the inclined surfaces 2a of the triangular prisms 2A and 2B are brought into contact with each other, as shown in FIG. 6 (b). The ultraviolet curable adhesive 6 is applied between the triangular side surfaces 2d and 2e of the other triangular prism 2B and the inclined stepped surfaces 11 and 12 adjacent thereto by the adhesive injector 16 and irradiated with ultraviolet rays. The adhesive 6 is cured.

According to the above configuration, as shown in FIG.
Is concentrated toward the one triangular prism 2A via the other triangular prism 2B, the intermolecular force between the inclined surfaces 2a of the both triangular prisms 2A and 2B acts strongly, and the inclined surfaces 2a are The two triangular prisms 2A and 2B can be securely integrated with each other, and thereby the polarizing beam splitter PB composed of the both triangular prisms 2A and 2B.
The optical characteristics (AS) of projection light and reflected light passing through S can be improved.

Further, only by fixing the other triangular prism 2B to the pickup main body 1 with the adhesive 6, the one triangular prism 2A is also fixed to the pickup main body 1, and the connection between the two triangular prisms 2A and 2B is made. And the two operations of fixing to the pickup body 1 can be performed simultaneously by one application operation of the adhesive 6, so that the work efficiency is high and the production cost can be reduced.

It is a longitudinal cross-sectional view of the principal part of the optical pick-up which is one Embodiment of this invention. It is an AA arrow line view of FIG. It is a BB arrow line view of FIG. It is a disassembled perspective view of the principal part. It is CC arrow line view of FIG. (A) is a longitudinal cross-sectional view which shows the front | former stage of the fixing procedure of a polarization beam splitter, (b) is a longitudinal cross-sectional view which shows the back | latter stage of the procedure. It is a schematic explanatory drawing which shows the fixed state of the polarization beam splitter. It is a schematic longitudinal cross-sectional view of an optical pick-up. It is a side view which shows an example of the prior art. (A)-(c) is a perspective view which shows the other example of the past. It is a schematic explanatory drawing which shows the effect | action of the tensile force concerning the polarization beam splitter.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Pickup main body 2A One triangular prism 2B The other triangular prism 2a Inclined surface 2b Vertical end surface 2c Horizontal end surface 2d, 2e Triangular side surface 6 Adhesive 8 Reference room 8a Vertical reference surface 8b Horizontal reference surface 8c, 8d Triangular reference surface 9 Communication chamber 9a to 9d Inner surface of the communication chamber 11, 12 Inclined step surface 15 Guide rail PBS Polarizing beam splitter

Claims (3)

A polarizing beam splitter formed by connecting the inclined surfaces of two triangular prisms having an inclined surface, a vertical end surface and a horizontal end surface facing the inclined surface, and a pair of left and right triangular side surfaces with an adhesive is provided in the pickup body. An optical pickup arranged to read information recorded on the disk by projecting laser light onto the disk through the polarization beam splitter and receiving the reflected light through the polarization beam splitter. In
A pair of left and right triangular reference surfaces opposed to the vertical reference surface and the horizontal reference surface and both triangular side surfaces facing the vertical and horizontal end surfaces of the one triangular prism without the adhesive connecting the inclined surfaces of the triangular prisms. And a vertical section triangular reference chamber provided with is formed in the pickup body,
A communication chamber communicating with the reference chamber is formed in the pickup body, a pair of left and right step surfaces are formed between both triangular reference surfaces of the reference chamber and the inner surface of the communication chamber, and on the inner surface of the communication chamber, A plurality of guide rails for guiding both triangular prisms toward the reference chamber are integrally projected at a predetermined interval, and one triangular prism is inserted into the reference chamber along the plurality of guide rails, Insert the other triangular prism into the communication chamber, bring the inclined surfaces of both triangular prisms into contact with each other, and apply adhesive between each triangular side surface of the other triangular prism and each step surface adjacent thereto. Features an optical pickup. A polarizing beam splitter formed by opposing the inclined surfaces of two triangular prisms each having an inclined surface, a vertical end surface and a horizontal end surface facing the inclined surface, and a pair of left and right triangular side surfaces is disposed in the pickup body. In the optical pickup configured to read the information recorded on the disk by projecting laser light onto the disk via the polarization beam splitter and receiving the reflected light via the polarization beam splitter, A vertical reference surface having a vertical reference surface and a horizontal reference surface facing the vertical end surface and the horizontal end surface of one triangular prism and a pair of left and right triangular reference surfaces facing both triangular side surfaces is formed in the pickup body. In addition, a communication chamber communicating with the reference chamber is formed in the pickup body, and communicates with both triangular reference surfaces of the reference chamber. A pair of left and right step surfaces are formed between the inner surface of the triangular prism, and one triangular prism is inserted into the reference chamber, the other triangular prism is inserted into the communication chamber, and the inclined surfaces of both triangular prisms meet. An optical pick-up characterized in that an adhesive is applied between each triangular side surface of the other triangular prism and each step surface adjacent thereto. 3. The optical pickup according to claim 2, wherein a plurality of guide rails for feeding both the triangular prisms toward the reference chamber are integrally projected on the inner surface of the communication chamber at a predetermined interval.

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