JP2002184020A - Hologram type optical pickup - Google Patents

Abstract

(57) Abstract: In a hologram type optical pickup, when fixing a hologram element to a cap, a gap for ventilation is surely formed between the cap and the hologram element in order to prevent dew condensation, and it is sufficient. Provided is a hologram type optical pickup fixed with adhesive strength. SOLUTION: A main unit including a light emitting unit, a light receiving unit, and a cap unit with a window covering the light emitting unit and the light receiving unit, a hologram element arranged on a top surface of the cap unit of the main unit, and the cap unit A hologram type optical pickup comprising an adhesive layer for adhering the hologram element to
The cross-sectional shape of the hologram element is narrow on the bottom side and wide on the opposing top side. There are 9 other items.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a CD, a CD-RO
The present invention relates to a hologram type optical pickup used for pickups such as M and MD, and a method of manufacturing the same.

[0002]

2. Description of the Related Art FIG. 14 is an external view of a conventional hologram type optical pickup. In the figure, a conventional hologram type optical pickup 50 includes a main body 51 and a hologram element 52. The main body 51 has a window 53 at the upper end.
A semiconductor cap 54 serving as a light source for reading a signal and a light receiving element 55 for reading a return light signal are built in a metal cap 53 having a, and a window 53 a is covered with a cap glass 56. Hologram element 5
Reference numeral 2 denotes a quartz glass substrate having a hologram pattern 57 for light deflection on its upper surface and a hologram pattern 57 on its bottom surface.
Grating patterns 58 for beam generation are respectively formed. Then, the hologram element 52 is fixed to the upper surface of the main body 51, that is, the outgoing / incident surface of the laser beam by the adhesive layer 59, and the hologram type optical pickup 50 is formed.

[0003] Such a hologram type optical pickup is manufactured in the process shown in FIG. That is, as shown in FIG. 13A, a temporary fixing ultraviolet curable resin 60 is applied to two or more places on the upper surface of the cap 51 with a syringe. Then, the hologram element 52 is mounted on the upper surface of the cap, and in this state, the return light from the optical disk passes through the hologram element and is detected by the light receiving element 55 inside the main body, and the position of the hologram element 52 is adjusted so that the light receiving state is optimized. Adjusted. Immediately after the completion of the position adjustment, ultraviolet rays are irradiated to temporarily fix the hologram element. Then, in order to fix the hologram element more firmly, two sides or 4
The main fixing ultraviolet resin 61 was applied to the sides and fixed.

[0004] The UV curable resin for temporary fixing and permanent fixing has a viscosity of about 400 p (poise) and a high fluidity.
At the time of temporary fixing, the resin applied immediately below the hologram element spreads to the interface between the cap and the hologram element during the position adjustment (60 in FIG. 13B), and the hologram element and the cap may be buried without gaps. Furthermore, if the permanent fixing ultraviolet resin is applied to four sides of the hologram element, the space between the hologram element and the cap can be completely sealed. As a result, it has been considered that the entry of moisture into the space can be suppressed.

However, in the hologram type optical pickup having such a configuration, it is impossible to completely suppress the invasion of moisture in an extremely high temperature environment. In such a sealed configuration, when moisture enters the space between the cap glass and the hologram element, dew condensation easily occurs. Once the dew condensation occurs, moisture is not released to the outside. When the water condensed, the laser beam shape was degraded and the optical signal intensity was reduced.

Therefore, in a hologram type optical pickup used in an environment where particularly severe performance against moisture is required, such as on-vehicle equipment, a gap is provided between the hologram element and the cap for ventilation. A proposed structure has been proposed. Japanese Patent Application Laid-Open No. 9-214065 discloses a hologram-type optical pickup in which a notch is provided on the side of the hologram element in contact with the upper surface of the cap.
FIG. 12 illustrates the manufacturing method. In this conventional example, a notch is provided in a bonding portion of the bottom surface of the hologram element with the ultraviolet curable resin for temporary fixing, so that excess resin is escaped. As shown in FIG. 12B, when the hologram element is adhered, excess resin remains in the cut portion of the hologram element and does not spread inside the hologram element. At this time, a gap is formed between the hologram element and the cap by the thickness of the adhesive layer, so that air permeability with the outside can be ensured.

Further, by applying the permanent fixing ultraviolet curable resin to the cut portion, there is an effect that a problem of resin flowing out of the cap can be eliminated as compared with an element having no cut portion. However, actually, it is not easy to form a cut portion in the hologram element. Particularly, it is difficult to form the cut portion in a commonly used glass hologram element.

Therefore, a conventional example in which a gap is formed without processing a hologram element is disclosed in Japanese Patent Laid-Open No. 10-335747.
No. 6,086,045. FIG. 11 is a diagram illustrating a conventional example. In the conventional example shown in FIG.
As a means for providing a gap between the hologram element 18 and the hologram element 18, a method of forming a projection 15b on the contact surface of the cap 15 with the hologram element 18 has been proposed. In this method, complicated processing is not required for the hologram element, but it is necessary to accurately form projections on the metal cap. However, the height of the projections could not be accurately formed due to poor processing accuracy in metal processing.

[0009]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and in a hologram type optical pickup, when a hologram element is fixed to a cap, a gap between the cap and the hologram element is prevented to prevent dew condensation. It is an object of the present invention to provide a hologram type optical pickup in which a gap for ventilation is surely formed and fixed with sufficient adhesive strength.

[0010]

The object of the present invention is achieved by the following means. That is, the hologram type optical pickup according to claim 1 is provided on a main body including a light emitting part, a light receiving part, and a cap with a window covering the light emitting part and the light receiving part, and is disposed on an upper surface of the cap part of the main body. In a hologram type optical pickup provided with a hologram element and an adhesive layer for adhering the hologram element to the cap portion, the main feature is that the cross-sectional shape of the hologram element is narrow on the bottom side and wide on the opposing top side. Features.

According to a second aspect of the present invention, there is provided the hologram type optical pickup according to the first aspect, wherein the hologram element has an inverted trapezoidal cross section.

According to a third aspect of the present invention, in the hologram type optical pickup according to the first aspect, the hologram element has an inverted convex cross section.

According to a fourth aspect of the present invention, there is provided a hologram type optical pickup, comprising: a main body having a light emitting section, a light receiving section, a cap with a window covering the light emitting section and the light receiving section, and an upper surface of the cap section of the main body. The main feature of the hologram type optical pickup provided with the hologram element to be provided and an adhesive layer for adhering the hologram element to the cap portion is that a groove is formed on the bottom surface of the hologram element.

A hologram type optical pickup according to a fifth aspect of the present invention is the hologram type optical pickup according to the fourth aspect, wherein the hologram element has two or more grooves.

According to a sixth aspect of the present invention, in the hologram type optical pickup according to the fourth or fifth aspect, at least one of the grooves is disposed inside the cap window.

A hologram type optical pickup according to a seventh aspect of the present invention is provided with a main body including a light emitting section, a light receiving section, a cap with a window covering the light emitting section and the light receiving section, and an upper surface of the cap section of the main body. The main feature of the hologram type optical pickup provided with the hologram element to be provided and an adhesive layer for adhering the hologram element to the cap portion is that a concave portion is formed on the bottom side of the hologram element.

According to an eighth aspect of the present invention, in the hologram type optical pickup according to the seventh aspect, the hologram element has two or more concave portions.

A hologram type optical pickup according to a ninth aspect of the present invention is provided with a main body including a light emitting section, a light receiving section, a cap section covering the light emitting section and the light receiving section, and an upper surface of the cap section of the main body section. In a hologram type optical pickup comprising a hologram element and an adhesive layer for adhering the hologram element to the cap portion, it is principal that the hologram element has a projection formed on the side of the adhesion surface with the upper surface of the cap portion. Characteristics.

A hologram type optical pickup according to a tenth aspect is the hologram type optical pickup according to the ninth aspect, wherein the hologram element has two or more convex portions.

[0020]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a first embodiment of the present invention. The hologram element 1 of the first embodiment has a hologram pattern 2 formed on the upper surface and a grating pattern 3 formed on the bottom surface. At least two surfaces of the hologram element are inclined surfaces 4, and the cross-sectional shape is an inverted trapezoidal shape. . In the temporary fixing of the hologram element, if the ultraviolet curing resin for temporary fixing is spot-applied just below the end of the inclined surface of the hologram element, and if the bottom of the hologram element is arranged so that a part of the ultraviolet curing resin is in contact with the hologram element, an extra The adhesive does not spread inside the hologram element. Therefore, a gap is formed between the cap and the hologram element by the thickness of the adhesive layer. In addition, if the UV curable resin for permanent fixing is applied to the angled side of the hologram element, it is possible to secure and secure high adhesiveness while preventing the hologram element from flowing into the side surface of the cap.

Such an inverted trapezoidal shape can be easily realized in a glass hologram element by cutting out with an angled blade when cutting out with a dicing saw.

FIG. 2 shows a second embodiment of the present invention. The hologram element 1 of the second embodiment has a hologram pattern 2 formed on the top surface and a grating pattern 3 formed on the bottom surface, and a step 5 is formed on at least two surfaces of the hologram element. As shown in the figure, the cross-sectional shape of the hologram element is inverted convex, so that even if the UV curable resin for temporary fixing is applied in a spot-like manner to the conventional position, the extra resin can spread around the glass and spread. Absent. Therefore, a gap is formed between the cap and the hologram element by the thickness of the adhesive layer. In addition, if the permanent curing ultraviolet curable resin is applied to the step portion 5 of the inverted convex hologram element, high adhesiveness can be ensured while preventing the resin from flowing into the side surface of the cap.

In the case of a glass hologram element, such an inverted trapezoidal shape is formed by first forming a groove with a wide blade at the time of cutting with a dicing saw, and then cutting the center of the groove with a narrow blade. It can be easily realized by cutting out the element.

FIG. 3 shows a third embodiment of the present invention. The hologram element 1 of the third embodiment has a hologram pattern 2 formed on the top surface and a grating pattern 3 formed on the bottom surface.
A book groove is formed. As shown in the figure, if two parallel grooves are formed on the cap bonding surface side of the hologram element, and an ultraviolet curing resin for temporary fixing is applied in a spot manner outside the two grooves and bonded, extra Since the resin is absorbed by the groove formed on the bottom of the hologram element, it does not spread inward. Therefore, a gap is formed between the cap and the hologram element by the thickness of the adhesive layer.

To make it easier to understand, FIG.
FIG. 7B is a cross-sectional view of the bottom surface of the hologram element according to the third embodiment, and FIG.

Further, by applying an ultraviolet-curing resin for permanent fixing along the sides parallel to the grooves of the hologram element, it is possible to secure the hologram element and the cap with high adhesiveness while securing the air permeability. Will be possible.

Such a shape can be easily realized with a dicing saw in a glass hologram element. When the grating pattern is formed by dry etching, it can be formed in the same step.

FIG. 5 shows a fourth embodiment of the present invention. As shown in the figure, in the hologram element of Example 4, four grooves 6 are formed in a grid pattern on the cap bonding surface side of the hologram element, and an ultraviolet curable resin for temporary fixing is spot-like on the outside of the grooves. If the adhesive is applied to the hologram element, the excess resin is absorbed by the groove formed on the bottom surface of the hologram element and does not spread inward. Therefore, a gap is formed between the cap and the hologram element by the thickness of the adhesive layer.

FIG. 6A shows a bottom surface of the hologram element.
(B) and (c) are cross-sectional views of the groove. In addition, by applying ultraviolet curing resin for permanent fixing along two sides parallel to the groove of the hologram element, it is possible to secure and secure high adhesiveness while securing air permeability between the hologram element and the cap. Become.

FIG. 7 shows a conceptual diagram of the state of adhesion of the hologram element when grooves are used. FIG. 7A is a sectional view,
(B) is a top view. As shown in the figure, the temporary fixing ultraviolet-curing resin 8 applied on the cap 7 is absorbed by the groove 6 on the bottom surface of the hologram element, and does not enter the interior any more, so that the gap 9 is secured.

FIG. 8 shows a fifth embodiment of the present invention. As shown in the figure, when the hologram element is fixed, if the groove formed on the bottom surface of the hologram element is arranged inside the cap window 7a, air permeability between the hologram element and the cap is ensured through the groove. I can do it.

FIG. 9 shows a sixth embodiment of the present invention. As shown in the drawing, the hologram element of Example 6 has at least two recesses 10, that is, recesses formed on the cap bonding surface side of the hologram element, and a temporary fixing ultraviolet curable resin is spot-shaped in the vicinity of the recess 10. By applying and bonding, excess resin is absorbed by the hologram element recess and does not spread inside. Therefore, a gap is formed between the cap and the hologram element by the thickness of the adhesive layer. In addition, by applying the UV curable resin for permanent fixing along two opposing sides of the hologram element, it is possible to secure and secure high adhesiveness while securing air permeability between the hologram element and the cap.

In FIG. 9, a circular concave portion is depicted.
Even if the shape is not circular, the effect is not changed at all if it is concave. Such a shape can be formed in the same step when a grating pattern is formed by dry etching in a glass hologram element.

FIG. 10 shows a seventh embodiment of the present invention. 10A is a perspective view, FIG. 10B is a bottom view, and FIG. 10C is a cross-sectional view. As shown in the figure, the hologram element of Example 7 has at least two protrusions 11 formed on the cap bonding surface side of the hologram element, and a temporary fixing ultraviolet curable resin is spot-applied immediately below the protrusions. If bonded, a gap of the height of the protrusion is formed between the cap and the hologram element, so that the extra resin does not spread inside the hologram element.

In a glass hologram element, such a shape is formed on the bottom of the hologram element by means of plasma CVD or the like.
This is realized by forming a film by depositing O, SiN, or the like and then etching it so as to remain in a predetermined region, or forming a film by depositing a metal by a vacuum deposition method and etching it so as to remain in a predetermined region. You can do it. Further, the projections can be formed by dry or wet etching. The thickness of the projection is preferably about 0.1 μm to 10 μm.

[0036]

The hologram type optical pickup according to any one of the first to third aspects is characterized in that the hologram element has an inverted trapezoidal shape or an inverted convex shape in cross section. By adopting such a shape, it is possible to reduce the amount of contact with the ultraviolet curable resin as compared with the conventional shape, and as a result, excessive resin does not fill the gap between the hologram element and the cap, so that the airflow is improved. Thus, a hologram optical pickup with high reliability and high reliability can be supplied.

In the hologram type optical pickup according to any one of the fourth to sixth aspects, the hologram element is provided on the side of the hologram element bonded to the cap.
It is characterized in that at least two grooves are formed to prevent excessive adhesive from spreading inside. This configuration has the effect of more actively releasing excess adhesive. If an ultraviolet curable resin for temporary fixing is applied to the outside of the groove of the hologram element, excess resin is absorbed by the groove, and as a result, the excess resin does not fill the gap between the hologram element and the cap, and the air permeability is improved. And a more reliable hologram-type optical pickup can be provided. Furthermore, if the hologram element is arranged so that at least one groove is inside the window of the cap, the space of the cap and the outside air can be ventilated through the groove.

According to the hologram type optical pickup of the present invention, at least two recesses are formed on the side of the hologram element to be bonded to the cap to prevent excessive adhesive from spreading inside. It is characterized by. This configuration has the effect of more actively releasing excess adhesive. If an ultraviolet curable resin for temporary fixing is applied to the vicinity of the concave portion of the hologram element, the excess resin is absorbed by the concave portion. As a result, the excess resin does not fill the gap between the hologram element and the cap, and the air permeability is improved. It is possible to supply a hologram type optical pickup which can be secured and has higher reliability.

In the hologram type optical pickup according to the ninth and tenth aspects of the present invention, at least two convex portions are formed on the surface of the hologram element to be bonded to the cap to prevent excessive adhesive from spreading inside. It is characterized by: This configuration has the effect that the provision of the convex portion on the hologram element side eliminates the spread of the ultraviolet ray curable resin for temporary fixing to the inside, and the gap can be reliably formed. If an ultraviolet curable resin for temporary fixing is applied directly below the convex portion of the hologram element, a gap is reliably formed between the cap and the hologram element at the convex portion, so that excess resin may spread inside the hologram element. Absent.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a first embodiment of a hologram element according to the present invention.

FIG. 2 is a perspective view showing a second embodiment of the hologram element according to the present invention.

FIG. 3 is a perspective view showing a third embodiment of the hologram element according to the present invention.

4 (a) is a bottom view of the embodiment of FIG. 3, and FIG. 4 (b) is a sectional view taken along line AA.

FIG. 5 is a perspective view showing a hologram element according to a fourth embodiment of the present invention.

6 (a) is a bottom view of the hologram element of FIG. 5, FIG. 6 (b) is a sectional view taken along line AA, and FIG. 6 (c) is a sectional view taken along line BB.

FIG. 7 is a conceptual diagram of a bonded state of the hologram element of FIG. 5,
FIG. 1A is a sectional view, and FIG. 1B is a top view.

8 (a) is a sectional view and FIG. 8 (b) is a top view of a hologram element according to a fifth embodiment of the present invention.

FIG. 9 is a perspective view showing a hologram element according to a sixth embodiment of the present invention.

10 (a) is a perspective view, FIG. 10 (b) is a bottom view, and FIG. 10 (c) is a seventh embodiment of the hologram element according to the present invention.
FIG. 2 is a sectional view taken along line AA.

11 (a) is a top view, FIG. 11 (b) is a front sectional view, and FIG. 11 (c) is a side sectional view.

FIGS. 12A to 12C are explanatory views of a method for manufacturing a conventional holographic optical pickup.

13 (a) to 13 (c) are explanatory views of a manufacturing process of a conventional hologram type optical pickup.

FIG. 14 is an external view of a conventional hologram type optical pickup.

[Explanation of symbols]

 (Reference numerals in FIGS. 1 to 10) 1 hologram element 2 hologram pattern 3 grating pattern 4 inclined surface 5 stepped portion 6 groove 7 cap 7a window 8 ultraviolet curing resin 9 gap 10 concave portion 11 convex portion (hereinafter, reference numeral in FIG. 11) 10 Hologram type optical pickup 11 Stem 12 Laser chip 13 Light emitting unit 14 Photodiode 15 Cap 15a Window 15b Projection 16 Window glass 18 Hologram element 19 UV curable resin 20 Lead 21 Gap 23 Space between optical component and cap (hereinafter, reference numeral in FIG. 12) Reference Signs List 3 hologram element 3a top surface of hologram element 3b bottom surface of hologram element 4 metal cap 4a window 7 cap glass 9 hologram pattern 10 grating pattern 12 hologram element notch 20 ultraviolet curing resin for temporary fixing One fixing ultraviolet curing resin (hereinafter, reference numerals in FIGS. 13 and 14) 50 hologram type optical pickup 51 main body 52 hologram element 53 metal cap 53a window 54 semiconductor laser 55 photodiode 56 cap glass 57 hologram pattern 58 grating pattern 59 Adhesive layer 60 UV curable resin for temporary fixing 61 UV curable resin for fixing

Claims (10)

[Claims] A hologram element disposed on an upper surface of the cap portion of the main body portion; a hologram element disposed on a top surface of the cap portion of the main body portion; A hologram type optical pickup comprising an adhesive layer for adhering the hologram element to a portion,
A hologram-type optical pickup, wherein a cross-sectional shape of the hologram element is narrow on a bottom side and wide on an opposing top side. 2. The hologram type optical pickup according to claim 1, wherein the hologram element has an inverted trapezoidal cross section. 3. The hologram type optical pickup according to claim 1, wherein the hologram element has an inverted convex cross section. 4. A main body comprising a light emitting part, a light receiving part, and a cap with a window covering the light emitting part and the light receiving part, a hologram element arranged on an upper surface of the cap part of the main body, and the cap A hologram type optical pickup comprising an adhesive layer for adhering the hologram element to a portion,
A hologram optical pickup, wherein a groove is formed on the bottom surface of the hologram element. 5. The hologram type optical pickup according to claim 4, wherein said hologram element has two or more grooves. 6. The hologram type optical pickup according to claim 4, wherein at least one of said grooves is arranged inside a cap window. 7. A main body including a light emitting unit, a light receiving unit, and a cap with a window covering the light emitting unit and the light receiving unit, a hologram element disposed on an upper surface of the cap of the main body, and the cap. A hologram type optical pickup comprising an adhesive layer for adhering the hologram element to a portion,
A hologram-type optical pickup, wherein a concave portion is formed on a bottom surface of the hologram element. 8. The hologram type optical pickup according to claim 7, wherein the hologram element has two or more concave portions. 9. A main body comprising a light emitting section, a light receiving section, and a cap with a window covering the light emitting section and the light receiving section, a hologram element arranged on an upper surface of the cap section of the main body, and the cap A hologram type optical pickup comprising an adhesive layer for adhering the hologram element to a portion,
A hologram-type optical pickup, wherein a projection is formed at the bottom of the hologram element. 10. The hologram type optical pickup according to claim 9, wherein the hologram element has two or more projections.