Compact optical pick-up lead with a vertically inclined substrate integrated with laser source and light detector

What is claimed is:

1. An optical pick-up device comprising:

a light-emitting and receiving unit composed of a rectangular substrate, a light-emitting element and a light-receiving element, said light-emitting and light-receiving elements being provided on one side surface of the substrate;

an objective lens for focusing a light beam emitted from said light-emitting element at a point on an optical axis thereof; and

a light path-changing means for directing said light beam emitted from the light-emitting element to said objective lens and directing an incident light entering through said objective lens to said light-receiving element;

wherein said light-emitting and receiving unit is disposed such that said surface of the rectangular substrate is inclined relative to the optical axis of said objective lens.

2. The optical pick-up device according to claim 1, wherein said light path-changing means includes a first light path-changing member disposed underneath said objective lens along the optical axis thereof, and a second light path-changing member for changing a light path of the light beam emitted from said light-emitting element such that the optical axis thereof is deflected in the direction normal to an optical axis of the light beam passing between said objective lens and said first light path-changing member.

3. The optical pick-up device according to claim 2, wherein said second light path-changing member is located at a position along the light path between said light-emitting and receiving unit and the first light path-changing member such that the optical axis of the light beam passing between said light-emitting and receiving unit and said second light path-changing member makes a right angle (90 degrees) relative to the optical axis of the light beam passing between said first and second light path-changing members.

4. The optical pick-up device according to claim 1, wherein a longitudinal peripheral side of said rectangular substrate extends in the direction approximately normal to the optical axis of said objective lens.

5. The optical pick-up device according to claim 1, wherein said light-emitting and receiving unit is so disposed that a longitudinal side of said rectangular substrate extends in the direction approximately normal to the optical axis of said objective lens.

6. An optical pick-up device comprising:

a light-emitting and receiving unit composed of a rectangular substrate, a light-emitting element and a light-receiving element, said light-emitting and light-receiving elements being provided on one side surface of the substrate;

an objective lens for focusing a light beam emitted from said light-emitting element at a point on an optical axis thereof; and

a light path-changing means for directing said light beam emitted from the light-emitting element to said objective lens and directing an incident light entering through said objective lens to said light-receiving element;

wherein said light-emitting and receiving unit is so disposed that said surface of the rectangular substrate is inclined relative to the optical axis of said objective lens;

wherein said light path-changing means includes a first light path-changing member disposed underneath said objective lens along the optical axis thereof, and a second light path-changing member for changing a light path of the light beam emitted from said light-emitting element such that the optical axis thereof is deflected in the direction normal to an optical axis of the light beam passing between said objective lens and said first light path-changing member; and further

wherein said second light path-changing member includes a reflecting surface on which the light beam emitted from said light-emitting element and a light beam coming from said first light path-changing member are reflected, and said reflecting surface of the second light path-changing member is so disposed as to be inclined at such an angle that the light beam emitted from said light-emitting element is deflected in the direction normal to the optical axis of the light beam passing between said objective lens and said first light path-changing member.

7. An optical pick-up device comprising:

a light-emitting and receiving unit composed of a rectangular substrate, a light-emitting element and a light-receiving element, said light-emitting and light-receiving elements being provided on one side surface of the substrate;

an objective lens for focusing a light beam emitted from said light-emitting element at a point on an optical axis thereof; and

a light path-changing means for directing said light beam emitted from the light-emitting element to said objective lens and directing an incident light entering through said objective lens to said light-receiving element;

wherein said light-emitting and receiving unit is disposed such that said surface of the rectangular substrate is inclined relative to the optical axis of said objective lens; and

wherein said light path-changing means is provided with an optical means disposed underneath said objective lens along the optical axis thereof and having a reflecting surface to change the light path of the light beam emitted from said light-emitting element and introduce an incident light beam entering through said objective lens into said light-receiving element, and the optical axis of the light beam passing between said light-emitting and receiving unit and said reflecting surface makes an angle of less than 90 degrees relative to the optical axis of the light beam passing through said objective lens and said reflecting surface.

8. An optical pick-up device comprising: a light-emitting and receiving unit composed of a rectangular substrate, a light-emitting element and a light-receiving element, said light-emitting and light-receiving elements being provided on one side surface of the substrate;

an objective lens for focusing a light beam emitted from said light-emitting element at a point on an optical axis thereof; and

a light path-changing means for directing said light beam emitted from the light-emitting element to said objective lens and directing an incident light entering through said objective lens to said light-receiving element;

wherein said light-emitting and receiving unit is disposed such that said surface of the rectangular substrate is inclined relative to the optical axis of said objective lens; and

wherein said light path-changing means is provided with a reflecting surface on which the light beam incident on said light path-changing means is reflected, said reflecting surface is inclined at an angle of less than 45 degrees relative to a plane normal to the optical axis of said objective lens.

9. An optical pick-up device comprising:

a light-emitting and receiving unit composed of a substrate, a light-emitting element and a light-receiving element, said light-emitting and light-receiving elements being provided on either one of opposite surfaces of the substrate;

an objective lens for focusing a light beam emitted from said light-emitting element at a point on an optical axis thereof; and

a light path-changing means for changing a light path of said light beam emitted from the light-emitting element and introducing an incident light entering through said objective lens into said light-receiving element;

wherein an optical axis of the light beam passing between said light-emitting and receiving unit and said light path-changing means makes an angle of less than 90 degrees relative to an optical axis of the light beam passing between said objective lens and said light path-changing means.

10. The optical pick-up device according to claim 9, wherein said light path-changing means includes a first light path-changing member disposed underneath said objective lens along the optical axis thereof, and a second light path-changing member for changing a light path of the light beam emitted from said light-emitting element such that the optical axis thereof is deflected in the direction normal to the optical axis of the light beam passing between said objective lens and said first light path-changing member.

11. The optical pick-up device according to claim 10, wherein said second light path-changing member is located at a position along a light path between said light-emitting and receiving unit and said first light path-changing member such that the optical axis of the light beam passing between said light-emitting and receiving unit and said second light path-changing member makes a right angle (90 degrees) relative to the optical axis of the light beam passing between said first and second light path-changing members.

12. The optical pick-up device according to claim 9, wherein a longitudinal peripheral side of said rectangular substrate extends in the direction approximately normal to the optical axis of said objective lens.

13. The optical pick-up device according to claim 9, wherein said light-emitting and receiving unit is so disposed that a longitudinal peripheral side of said rectangular substrate extends in the direction approximately normal to the optical axis of said objective lens.

14. An optical pick-up device comprising:

a light-emitting and receiving unit composed of a substrate, a light-emitting element and a light-receiving element, said light-emitting and light-receiving elements being provided on either one of opposite surfaces of the substrate;

an objective lens for focusing a light beam emitted from said light-emitting element at a point on an optical axis thereof; and

a light path-changing means for changing a light path of said light beam emitted from the light-emitting element and introducing an incident light entering through said objective lens into said light-receiving element;

wherein an optical axis of the light beam passing between said light-emitting and receiving unit and said light path-changing means makes an angle of less than 90 degrees relative to an optical axis of the light beam passing between said objective lens and said light path-changing means;

wherein said light path-changing means includes a first light path-changing member disposed underneath said objective lens along the optical axis thereof, and a second light path-changing member for changing a light path of the light beam emitted from said light-emitting element such that the optical axis thereof is deflected in the direction normal to the optical axis of the light beam passing between said objective lens and said first light path-changing member; and further

wherein said second light path-changing member includes a reflecting surface on which the light beam emitted from said light-emitting element and a light beam coming from said first light path-changing member are reflected, and said reflecting surface of the second light path-changing member is so disposed as to be inclined at an angle capable of deflecting the light beam emitted from said light-emitting element in the direction normal to the optical axis of the light beam passing between said objective lens and said first light path-changing member.

15. An optical pick-up device comprising:

a light-emitting and receiving unit composed of a substrate, a light-emitting element and a light-receiving element, said light-emitting and light-receiving elements being provided on either one of opposite surfaces of the substrate;

an objective lens for focusing a light beam emitted from said light-emitting element at a point on an optical axis thereof; and

a light path-changing means for changing a light path of said light beam emitted from the light-emitting element and introducing an incident light entering through said objective lens into said light-receiving element;

wherein an optical axis of the light beam passing between said light-emitting and receiving unit and said light path-changing means makes an angle of less than 90 degrees relative to an optical axis of the light beam passing between said objective lens and said light path-changing means;

wherein said light path-changing means includes a first light path-changing member disposed underneath said objective lens along the optical axis thereof, and a second light path-changing member for changing a light path of the light beam emitted from said light-emitting element such that the optical axis thereof is deflected in the direction normal to the optical axis of the light beam passing between said objective lens and said first light path-changing member; and further

wherein said second light path-changing member includes a reflecting surface on which the light beam emitted from said light-emitting element and a light beam coming from said first light path-changing member are reflected, and said reflecting surface of the second light path-changing member is so disposed as to be inclined at an angle capable of deflecting the light beam emitted from said light-emitting element in the direction normal to the optical axis of the light beam passing between said objective lens and said first light path-changing member.

16. An optical pick-up device comprising:

a light-emitting and receiving unit composed of a substrate, a light-emitting element and a light-receiving element, said light-emitting and light-receiving elements being provided on either one of opposite surfaces of the substrate;

an objective lens for focusing a light beam emitted from said light-emitting element at a point on an optical axis thereof; and

a light path-changing means for changing a light path of said light beam emitted from the light-emitting element and introducing an incident light entering through said objective lens into said light-receiving element;

wherein an optical axis of the light beam passing between said light-emitting and receiving unit and said light path-changing means makes an angle of less than 90 degrees relative to an optical axis of the light beam passing between said objective lens and said light path-changing means; and

wherein said light path-changing means is provided with an optical means disposed underneath said objective lens along the optical axis thereof and having a reflecting surface to change a light path of the light beam emitted from said light-emitting element and introduce an incident light beam entering through said objective lens into said light-receiving element, and an optical axis of the light beam passing between said light-emitting and receiving unit and said reflecting surface makes an angle of less than 90 degrees relative to an optical axis of the light beam passing through said objective lens and said reflecting surface.

17. An optical pick-up device comprising:

a light-emitting and receiving unit composed of a rectangular substrate, a light-emitting element and a light-receiving element, said light-emitting and light-receiving elements being arranged in line on either one of opposite surfaces of the substrate;

an objective lens for focusing a light beam emitted from said light-emitting element at a point on an optical axis thereof;

a supporting means for supporting said objective lens to move in the direction parallel with an optical axis of said objective lens and in the direction of a plane normal to the optical axis of said objective lens;

a light path-changing means for directing said light beam emitted from the light-emitting element toward said objective lens and directing an incident light entering through said objective lens toward said light-receiving element; and

a base to which said light-emitting and receiving unit, said supporting means and said light path-changing means are mounted and which is provided with a guidable support member engaging with a linear guide means;

wherein said light-emitting and receiving unit is disposed on said base such that one of a pair of opposed longitudinal peripheral sides of said rectangular substrate extends in the direction approximately normal to the optical axis of said objective lens, and a surface of said rectangular substrate is inclined relative to the optical axis of said objective lens.

18. The optical pick-up device according to claim 17, wherein said guidable support member is disposed on said base so as to extend in the direction approximately normal to the supporting direction of said objective lens by said supporting means.

19. The optical pick-up device according to claim 17, wherein said light path-changing means includes a first light path-changing member disposed underneath said objective lens along the optical axis thereof, and a second light path-changing member for changing a light path of the light beam emitted from said light-emitting element such that an optical axis thereof is deflected in the direction normal to an optical axis of the light beam passing between said objective lens and said first light path-changing member.

20. The optical pick-up device according to claim 19, wherein said supporting means is provided with a reference portion for movement, which is located at a position spaced apart from the optical axis of said objective lens in the direction normal to said linear guide means, and said objective lens is supported so as to be movable in the directions parallel with the optical axis of said objective lens and in the direction of a plane normal to the optical axis of said objective lens.

21. The optical pick-up device according to claim 19, wherein said second light path-changing member is located in the proximity of said guidable support member.

22. An optical pick-up device comprising:

a light-emitting and receiving unit composed of a substrate, a light-emitting element and a light-receiving element, said light-emitting and light-receiving elements being provided on either one of opposite surfaces of the substrate;

an objective lens for focusing a light beam emitted from said light-emitting element at a point on an optical axis thereof; and

a light path-changing means for changing a light path of said light beam emitted from the light-emitting element and introducing an incident light entering through said objective lens into said light-receiving element;

wherein an optical axis of the light beam passing between said light-emitting and receiving unit and said light path-changing means makes an angle of less than 90 degrees relative to an optical axis of the light beam passing between said objective lens and said light path-changing means; and

wherein said light path-changing means is provided with a reflecting surface on which the light beam incident on said light path-changing means is reflected and said reflecting surface is inclined at an angle of less than 45 degrees relative to a plane normal to the optical axis of said objective lens.

23. An optical pick-up device comprising:

a light-emitting and receiving unit composed of a rectangular substrate, a light-emitting element and a light-receiving element, said light-emitting and light-receiving elements being arranged in line on either one of opposite surfaces of the substrate;

an objective lens for focusing a light beam emitted from said light-emitting element at a point on an optical axis thereof;

a supporting means for supporting said objective lens to move in the direction parallel with an optical axis of said objective lens and in the direction of a plane normal to the optical axis of said objective lens;

a light path-changing means for directing said light beam emitted from the light-emitting element toward said objective lens and directing an incident light entering through said objective lens toward said light-receiving element; and

a base to which said light-emitting and receiving unit, said supporting means and said light path-changing means are mounted and which is provided with a guidable support member engaging with a linear guide means, wherein said light-emitting and receiving unit is so disposed on said base that one of a pair of opposed longitudinal peripheral sides of said rectangular substrate extends in the direction approximately normal to the optical axis of said objective lens, and a surface of said rectangular substrate is inclined relative to the optical axis of said objective lens;

wherein said light path-changing means includes a first light path-changing member disposed underneath said objective lens along the optical axis thereof, and a second light path-changing member for changing a light path of the light beam emitted from said light-emitting element such that an optical axis thereof is deflected in the direction normal to an optical axis of the light beam passing between said objective lens and said first light path-changing member; and

wherein said second light path-changing member is located at a position along a light path between said light-emitting and receiving unit and said first light path-changing member such that an optical axis of the light beam passing between said light-emitting and receiving unit and said second light path-changing member makes a right angle (90 degrees) relative to an optical axis of the light beam passing between said first and second light path-changing members.

Description Submit all comments and votes

TECHNICAL FIELD

This invention relates to an optical pick-up device, and more particularly to an optical pick-up device using a light-emitting and receiving unit which includes a light-emitting element and a light-receiving element both formed integrally on a common substrate.

BACKGROUND ART

It is hitherto known that an optical recording medium such as an optical disc is used as a recording medium for a recording and/or reproducing apparatus. In the recording and/or reproducing apparatus of such a type, an optical pick-up device is provided to write and/or read out information signals on the optical recording medium. The optical pick-up device includes a light-emitting element such as a semiconductor laser for emitting a light beam and a light receiving element such as a photodetector. The optical pick-up device has a function for carrying out recording of information signals on the optical recording medium by radiating the light beam thereon, or reproducing of the information signals on the optical recording medium by detecting a returning light reflected on the optical recording medium by the light receiving element.

The optical pick-up device is provided with an objective lens which serves for focusing and radiating a light beam emitted from the light-emitting element on a signal recording surface of the optical recording medium.

Further, the optical pick-up device is provided with an objective lens-driving device for controllably driving the objective lens both in the focusing direction parallel with an optical axis of the objective lens and in the tracking direction normal to the optical axis of the objective lens whereby the signal recording surface of the rotatably operated optical recording medium is allowed to be located at the position in a depth of focus of the light beam radiated through the objective lens and the light beam radiated through the objective lens is permitted to exactly follow recording tracks of the rotatably operated optical recording medium.

Meanwhile, with respect to the recording and/or reproducing apparatus of the type in which an optical recording medium is used, there has been a demand for realizing compactness and thinness of the apparatus. Actually, recording and/or reproducing apparatuses currently used have such a small size as approximately similar to an outer diameter of the optical recording medium to be loaded thereon. In addition, since the optical recording medium is capable of recording information signals with a high density, there has been proposed and employed the recording and/or reproducing apparatus on which the optical recording medium having a size as small as 64 mm or less can be loaded. However, there is still a further demand for compactness and thinness of the recording and/or reproducing apparatus.

In order to realize the compactness and thin thickness of the recording and/or reproducing apparatus, it is necessary to achieve a compactness and a thinness of an optical pick-up device which serves as a means for recording and/or reproducing information signals on the optical recording medium.

For the purpose of achieving the compactness and thinness of the optical pick-up device, known optical pick-up device has, for example, such a structure that the light beam to be radiated on the optical recording medium is first emitted in the direction normal to an optical axis of an objective lens and then deflected by a light path-changing means such as a light-turning mirror to thereby introduce the light beam into the objective lens.

Thus, by emitting the light beam in the direction normal to the optical axis of the objective lens, it becomes possible to reduce a height between the light-emitting element and the objective lens whereby compactness of the optical pick-up device is achievable. Further, another proposal has been made to realize the compactness of the optical pick-up device, in which the light-emitting element for emitting the light beam and a light-receiving element for detecting the returning light reflected on the optical recording medium are disposed on a common substrate to form an integrated light-emitting and receiving unit. The use of such a light-emitting and receiving unit can save or reduce an accommodation space required for providing individual light-emitting and light-receiving elements whereby compactness of the optical pick-up device can be achieved.

Incidentally, in the previously proposed optical pick-up device, the light-emitting and receiving unit is uprightly elected on a base, on which an objective lens-driving device is also mounted, such that the light beam emitted from the light-emitting element proceeds in the direction normal to the optical axis of the objective lens. However, the upright arrangement of the light-emitting and receiving unit on the base makes it difficult to obtain the optical pick-up device having a thin thickness, because reduction of the thickness is prohibited by the height of the light-emitting and receiving unit uprightly disposed on the base.

DISCLOSURE OF THE INVENTION

Therefore, an object of the present invention is to provide an optical pick-up device having a further compact size and thinned thickness whereby compactness and thinness of an recording and/or reproducing apparatus employing an optical recording medium can be achieved.

In one aspect of the present invention, the optical pick-up device comprises a light-emitting and receiving unit composed of a light-emitting element and a light-receiving element both provided on one side surface of a rectangular substrate, an objective lens for focusing a light beam emitted from the light-emitting element at a point existing along an optical axis thereof, and a light path-changing means for directing the light beam emitted from the light-emitting element toward the objective lens and introducing an incident light entering through the objective lens into the light-receiving element. The light-emitting and receiving unit is so disposed that the one side surface of the rectangular substrate is inclined relative to the optical axis of the objective lens.

In the optical pick-up device of the present invention, the light path-changing means may include a first light path-changing member disposed underneath the objective lens along the optical axis thereof, and a second light path-changing member for deflecting the light beam emitted from the light-emitting element such that the optical axis of the deflected light beam extends in the direction normal to the optical axis of the light beam passing between the objective lens and the first light path-changing member.

In another aspect of the present invention, the optical pick-up device further comprises a supporting mechanism for supporting the objective lens such that the objective lens is movable in the directions both parallel with and normal to the optical axis of the objective lens, and a base to which the light-emitting and receiving unit, the supporting mechanism and the light path-changing means are mounted and which is formed with a guidable support member engaging with a linear guide means. The light-emitting and receiving unit of the optical pick-up device is so disposed on the base that one of a pair of opposed longitudinal sides of the rectangular substrate extends in the direction approximately normal to the optical axis of the objective lens, and a surface of the rectangular substrate is inclined relative to the optical axis of the objective lens.

The supporting mechanism is provided with a reference portion for movement of the objective lens, which is located at a position spaced from the objective lens in the direction normal to the linear guide means. The objective lens is supported so as to be movable in the directions parallel with and normal to the optical axis of the objective lens.

In the optical pick-up device according to the present invention, the light-emitting element and the light-receiving element are disposed on either one of opposite surfaces of the rectangular substrate. The light-emitting and receiving unit is so arranged that the flat surface of the rectangular substrate is inclined relative to the optical axis of the objective lens whereby the optical pick-up device having a thin thickness can be realized without being limited by a height of the substrate of the light-emitting and receiving unit.

Further, in the optical pick-up device according to the present invention, in addition to the special arrangement in which the flat surface of the substrate of the light-emitting and receiving unit is inclined relative to the optical axis of the objective lens, there is provided the light path-changing means for directing the light beam emitted from the light-emitting element of the light-emitting and receiving unit toward the objective lens and introducing the incident light beam entering through the objective lens toward the light-receiving element of the light-emitting and receiving unit. The light path-changing means further includes the first light path-changing member disposed underneath the objective lens along the optical axis thereof, and the second light path-changing member for deflecting the light beam emitted from the light-emitting element such that the optical axis of the deflected light beam extends in the direction normal to the optical axis of the light beam passing between the objective lens and the first light path-changing member. As a result, a distance between the light-emitting and receiving unit and the objective lens is reduced whereby compactness of the optical pick-up device can be achieved in addition to thinness thereof.

Further and additional objects and advantages of the present invention will become more apparent from the following description concerning the preferred embodiments with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing an optical pick-up device according to a first embodiment of the present invention.

FIG. 2 is an exploded perspective view of the optical pickup device shown in FIG. 1.

FIG. 3 is a top plan view of the optical pick-up device shown in FIG. 1.

FIG. 4 is a sectional view showing a light-emitting and receiving unit employed in the optical pick-up device according to the present invention.

FIG. 5 is a perspective view showing an outer appearance of the light-emitting and receiving unit.

FIG. 6 is a sectional view showing a condition in which the light-emitting and receiving unit is mounted on a base.

FIG. 7 is a side view showing a relation of arrangement between the light-emitting and receiving unit and an objective lens.

FIG. 8 is a side view showing a relation of arrangement between first and second light-turning mirrors and the objective lens.

FIG. 9 is a perspective view showing a relation of arrangement between the light-emitting and receiving unit, the first and second light-turning mirrors and the objective lens.

FIG. 10 is an exploded perspective view showing an optical pick-up device according to a second embodiment of the present invention.

FIG. 11 is a perspective view showing a relation of arrangement between a light-emitting and receiving unit, a light-turning mirror and an objective lens according to the second embodiment of the present invention.

BEST MODE OF CARRYING OUT THE INVENTION

The optical pick-up device according to the present invention is described hereinafter by referring to the accompanying drawings.

The optical pick-up device of the present invention is so designed as to be incorporated into a disc recording and/or reproducing apparatus in which an optical disc is used as a recording medium. As shown in FIGS. 1 and 2, the optical pick-up device includes a base 2 guidably supported on a linear guide shaft 1 provided in the recording and/or reproducing apparatus and an objective-lens driving device 3 mounted on the base 2. The base 2 is movable in the radial direction of the optical disc D loaded in the recording and/or reproducing apparatus an entire radial distance thereof.

The objective-lens driving device 3 used in the optical pick-up device of the present invention is now explained below. As shown in FIGS. 1 and 2, the objective-lens driving device 3 is composed of a lens holder 5 to which an objective lens 4 is securely mounted, a coil bobbin 8, a plurality of resilient support members 7 which supports the lens holder 5 on a front side thereof, a stationary member 8 to which a rear base portion of each of the resilient support members 7 is fixedly coupled, and a support plate 9 on which the stationary member 8 is securely supported.

The lens holder 5 is provided at a free end thereof with an opening 10 into which the objective lens 4 is securely fitted. Further, the lens holder 5 is provided at the other end thereof with another opening 11 into which the coil bobbin 8 is securely fitted.

The objective lens 4 mounted to the lens holder 5 is made of glass or a light-permeable synthetic resin which is shaped into a single-eye lens having non-spherical side surfaces.

Meanwhile, the lens holder 5 is formed of a molded synthetic resin and integrated with four resilient support members 7 which resiliently supports the lens holder 5 so as to permit the lens holder 5 to move in the directions both parallel and normal to an optical axis of the objective lens 4. Each of these resilient support members 7 may be produced by stamping a flexible and electrically conductive sheet metal material such as phosphor bronze, stainless steel, etc., into an elongated strip plate. The four resilient support members 7 are so arranged that each pair of resilient support members is disposed in parallel with each other on both sides of the lens holder 5. Each of the resilient support members 7 has a front side portion fixed to respective opposite sides of a body portion of the lens holder 5 to which the objective lens 4 and the coil bobbin 6 are mounted and in which a center of gravity thereof exists, and the base portion secured to the stationary member 8 mounted on the support plate 9.

That is, the lens holder 5 and the stationary member 8 are integrally connected with each other through the four resilient support members 7 which are disposed in parallel with each other and coupled at the front side portion thereof with the lens holder 5 and at the rear base portion thereof with the stationary member 8 by using an out-sert molding method.

Thus, the rear base portion of each of the resilient support members 7 is secured to the stationary member 8 mounted on the support plate 9 while the elongated strip-like front side portion of each of the resilient support members 7 is secured to the opposite sides of the lens holder 5 so that the lens holder 5 is supported in such a manner as being flexibly movable in both the directions parallel with the optical axis of the objective lens 4 mounted to the lens holder 5 (in the focusing direction indicated by an arrow F in FIG. 1) and normal to the optical axis of the objective lens 4 (in the tracking direction indicated by an arrow T in FIG. 1).

Further, each of the resilient support members 7 is formed integrally with an inner folded arm portion 12 extending from the front distal end toward the rear base portion thereof in parallel with the elongated strip-like front side portion thereof. The inner folded arm portions are embedded into the opposite sides of the lens holder 5 and have connecting end portions 13 which serve for electrical connection with terminals of the coil bobbin 6 received in the opening 11 of the lens holder 5, as described hereinafter. The connecting end portions 13 are projected into a recess 11a formed on a portion of an inner wall which defines the opening 11, as shown in FIG. 2.

Meanwhile, an end portion of the rear base portion of each resilient support member 7 is so disposed as to project from a rear side surface of the stationary member 8 backwardly to provide an input terminal 14 at which a focusing drive signal and a tracking drive signal from a servo circuit (not shown) are entered. These input terminals 14 are connected with a flexible printed circuit board 15 derived from the servo circuit.

The coil bobbin 6 mounted to the lens holder 5 is formed of a molded synthetic resin which is an electrically insulating material. As shown in FIG. 2, the coil bobbin 6 is of a rectangular cylindrical shape having a rectangular through-hole 16 at a central portion thereof and has an outer size capable of being received in the opening 11 formed through the lens holder 5. The coil bobbin 6 is provided at upper and lower ends thereof with upper and lower flanges 17 and 18, respectively. A focusing coil 19 is wound on a portion between the upper and lower flanges of the coil bobbin 6. Specifically, the focusing coil 19 is wound on an outer circumferential surface of the portion extending between the upper and lower flanges 17 and 18 along the direction of the optical axis of the objective lens 4 so that the winding of the focusing coil 19 is of a cylindrical shape. The focusing coil 19 is provided at a side portion thereof with a pair of coiled portions 20a and 20b each having a flat rectangular shape and connected together to constitute a tracking coil 20. The coiled portions 20a and 20b of the tracking coil 20 are formed from a continuously wound thin wire.

In a rear side portion of the coil bobbin 6 opposed to the portion where the tracking coil 20 is provided, a pair of terminal pins 21 are projected from each of the upper and lower flanges 17 and 18. Leading and trailing ends of each of the focusing and tracking coils 19 and 20 are wound on the respective terminal pins 21.

The coil bobbin 8 as constructed above are inserted and received into the opening 11 of the lens holder 5 such that the respective terminal pins 21 are located in the recess 11a. In this condition, the coil bobbin 6 may be fixed to the lens holder 5 by using an adhesive, if desired. Further, the respective terminal pins 21 of the coil bobbin 6 is electrically connected to the connecting end portions 13 of the resilient support members 7 which support the lens holder 5, by soldering or using a conductive adhesive. By connecting the respective terminal pins 21 with the connecting end portions of the resilient support members 7, the focusing and tracking coils 19 and 20 are electrically coupled with the servo circuit through the plural conductive resilient support members 7 and the flexible printed circuit board 15 connected thereto.

The support plate 9, on which the stationary member 8 supporting the lens holder 5 through a plurality of resilient support members 7 is mounted and which constitutes a magnetic circuit section of the objective-lens driving device 3, is formed of a magnetic material having a high rigidity, such as metal. The support plate 9 is provided at a rear portion thereof with a mounting block 22 on which the stationary member 8 is mounted, and at a front portion thereof with a pair of opposed yokes 23 and 24 uprightly extending from a the front portion of the support plate 9. A magnet 25 is secured onto an inner surface of the one yoke 23 such that a magnetic gap is formed between the magnet 25 and the other yoke 24.

As shown in FIG. 1, the stationary member 8 is mounted on the mounting portion 22 provided on the support plate 9, to dispose the lens holder 5 on the support plate 9 whereby a complete objective-lens driving device 3 is assembled.

Meanwhile, the assembling of the lens holder 5 on the support plate 9 is performed such that the focusing and tracking coils 19 and 20 of the coil bobbin 6 mounted on the lens holder 5 are inserted into the magnetic gap formed between the magnet 25 and the other yoke 24. At this time, the stationary member 8, which is coupled with the rear base portion of each of the resilient support members 7 supporting the lens holder 5, is secured to the mounting portion 22 of the support plate 9 by using an adhesive or the like.

The base 2, to which the above-constructed objective-lens driving device 3 is mounted, is made of die-cast aluminum or a molded synthetic resin and provided on one side thereof with a pair of guide blocks 31 and 32 formed integrally therewith and serving as a support for supporting the base 2 on the linear guide shaft 1. The guide blocks 31 and 32 are formed with through holes 33 having center axes exactly aligned with each other.

As shown in FIG. 1, the objective-lens driving device 3 is mounted on the base 2 such that the objective lens 4 thereof is located on the side where a pair of the guide blocks 31 and 32 are provided, and the plural resilient support members 7 supporting the lens holder 5 extend in the direction perpendicular to the axial direction of the linear guide shaft 1 which extends through the guide blocks 31 and 32. The objective-lens driving device 8 is fixed onto the base 2 by fastening bolts 34 which are screwed through a portion of the support plate 9 into the base 2. On the side opposed to the side where the guide blocks 31 and 32 are formed, the objective-lens driving device 3 is provided with a plate spring 36 which cooperates with the support plate 9 constituting a portion of the objective-lens device 3 so as to interpose therebetween a slide guide member 35 formed within the recording and/or reproducing apparatus. The plate spring 36 is of an approximate L-shape and has one end portion opposed to the rear portion of the support plate 9 and extending in the direction of the axis of the linear guide shaft 1 which extends through the guide blocks 31 and 32. The plate spring 36 is fixed to the base 2 by one of the fastening bolts 34 which serve for securing the support plate 9 to the base 2.

Incidentally, the plate spring 36 is formed at the middle thereof with an arcuate swelled portion 36a at which the plate spring comes into pressure contact with a point of the slide guide member 35.

The base 2, on which the objective-lens driving device 3 is mounted, is disposed within the recording and/or reproducing apparatus such that the linear guide shaft 1 is inserted into and engaged with the through-holes 33 of the guide blocks 31 and 32 and one side portion of the slide guide member 35 is interposed between the plate spring 36 and the support plate 9. The base 2 is so operated as to move in the radial direction of the optical disc D while being guided along the linear guide shaft 1 by means of a drive motor (not shown) and a gear drive mechanism (also not shown) for transmitting a driving force of the drive motor.

Provided on the base 2 is a light-emitting and receiving unit 41 which is composed integrally of a light-emitting element for emitting a light beam to be radiated to a signal-recording or carrying surface of the optical disc D through the objective lens 4, and a light-receiving element for receiving a returning light reflected on the signal-recording or carrying surface of the optical disc D.

As shown in FIGS. 3 and 4, the light-emitting and receiving unit 41 includes a light-emitting and receiving composite element 40 which is composed of a semiconductor laser 42 constituting the light-emitting element for emitting a light beam to be radiated to the signal-recording or carrying surface of the optical disc D, and first and second photodetectors 43 and 44 constituting the light-receiving element for receiving the returning light reflected on the signal-recording or carrying surface of the optical disc D. The semiconductor laser 42 and the photodetectors 43 and 44 are integrated on a common semiconductor substrate 45. On one side surface 45a of the semiconductor substrate 45 of the composite element 40, the first and second photodetectors 43 and 44 are disposed in parallel with each other. Further, on the surface 45a of the semiconductor substrate 45, the semiconductor laser 42 is also disposed in parallel with the first and second photodetectors 43 and 44.

Each of the first and second photodetectors 43 and 44 is divided into a plurality of light-receiving areas. These photodetectors 43 and 44 can transmit an output signal such as a focusing error signal, a tracking error signal and a reproducing signal indicative of information recorded on the optical disc D on the basis of addition or subtraction of outputs obtained by detecting the returning light reflected on the optical disc D by the respective areas of the photodetectors 43 and 44.

The semiconductor laser 42 is mounted on the surface 45a of the semiconductor substrate 45 such that a light-emitting surface 42a thereof for emitting a light beam L.sub.1 extends in the direction perpendicular to the surface 45a of the semiconductor substrate 45 and is directed toward the side where th