WO2007132834A1

WO2007132834A1 - Composite optical device

Info

Publication number: WO2007132834A1
Application number: PCT/JP2007/059924
Authority: WO
Inventors: Toshiaki Takano; Jun Murata
Original assignee: Panasonic Corporation
Priority date: 2006-05-16
Filing date: 2007-05-15
Publication date: 2007-11-22

Abstract

Disclosed is a composite optical device, particularly a composite optical device wherein a second optical unit is joined to a first optical unit. This composite optical device is excellent in environmental resistance. Specifically disclosed is a composite optical device (10) comprising a first glass optical unit (11) and a second glass optical unit (14). The second optical unit (14) is joined to the first optical unit (11) on a lens surface (12) of the first optical unit (11), and has a lens surface (15) and a contact surface (16). The lens surface (12) and the lens surface (15) respectively have a first rough surface (12a) and a second rough surface (15a).

Description

Specification

Compound optical element

Technical field

The present invention relates to a composite optical element, and more particularly to a composite optical element in which a second optical part is bonded to a first optical part.

Background art

Conventionally, a composite optical element including two or more optical units is known. In many cases, a composite optical element is formed by bonding different materials (for example, glass and resin), and a diffractive surface may be formed on the bonded surface.

[0003] On the diffractive surface, a slit-like or groove-like lattice structure having a fine equidistant interval of several tens of force and several hundreds per minute interval (about 1 mm) is formed. For this reason, when a light beam is incident on a composite optical element having a diffractive surface, a diffracted light beam is generated in a direction determined by the pitch (interval) of the slits and grooves and the wavelength of the light. They can be collected and used as a lens. Therefore, in such a composite optical element, the refractive index increases as the wavelength increases, unlike lenses made of glass or resin, and the h-line (404.7 nm) to c-line (656.3 nm). It is possible to increase the diffraction efficiency to 90% or more in a wide wavelength region.

Patent Document 1: Japanese Patent Laid-Open No. 11-287904

Patent Document 2: JP-A-11 305126

Disclosure of the invention

Problems to be solved by the invention

[0004] By the way, in many composite optical elements, a second optical part made of a resin is bonded to a first optical part that also has glass power. In general, resin has poor environmental resistance compared to glass, that is, its characteristics change due to environmental changes such as temperature changes and humidity changes, so depending on the conditions of use of the composite optical element, There was a risk of deterioration of characteristics.

[0005] The present invention has been made in view of the power, and the object of the present invention is to withstand the environment. An object of the present invention is to provide a composite optical element having excellent properties.

Means for solving the problem

[0006] The composite optical element of the present invention has a first optical functional surface, which is made of glass, and a second optical portion made of glass that is bonded to the first optical part on the first optical functional surface. And. The second optical unit has a bonding surface where the second optical unit is bonded to the first optical unit, and a second optical functional surface existing on the opposite side of the bonding surface. At least a part of the first optical functional surface has a first uneven surface portion, and at least a part of the second optical functional surface has a second uneven surface portion. The “optical functional surface” is an incident / exit surface or a reflective surface.

The invention's effect

In the present invention, a composite optical element having excellent environmental resistance can be provided.

Brief Description of Drawings

FIG. 1 is a schematic cross-sectional view of a composite optical element according to Embodiment 1.

FIG. 2 is a cross-sectional process diagram illustrating a method of molding a composite optical element according to the first embodiment.

FIG. 3 is a schematic cross-sectional view of a composite optical element according to the second embodiment.

FIG. 4 is a schematic sectional view of a composite optical element according to the third embodiment.

FIG. 5 is a schematic cross-sectional view of a composite optical element according to Embodiment 4.

FIG. 6 is a schematic sectional view of a composite optical element according to the fifth embodiment.

FIG. 7 is a schematic cross-sectional view of a composite optical element according to Embodiment 6.

Explanation of symbols

[0009] 10, 20, 30, 40, 50, 60 Compound optical element

11, 31, 41, 51, 61 1st optical section

12, 32, 42, 52, 62 Lens surface (first optical functional surface)

12a, 32a, 42a, 52a, 62a First uneven surface

14, 34, 44, 54, 64 Second optical part

15, 35, 45, 55, 65 Lens surface (second optical function surface) 15a, 35a, 45a, 55a, 65a Second uneven surface

16, 36, 46, 56, 66 Joint surface

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The present invention is not limited to the following embodiment.

[Embodiment 1 of the Invention]

In Embodiment 1, a composite lens is taken as an example of a composite optical element, and its configuration and forming method are shown.

FIG. 1 is a schematic cross-sectional view of a composite optical element 10 according to the first embodiment.

The composite optical element 10 according to the present embodiment includes a first optical unit 11 and a second optical unit 14. The first optical unit 11 is an aspheric lens made of glass, and has two lens surfaces, that is, a lens surface (first optical functional surface) 12 and a lens surface 13. The second optical unit 14 also has a glass force and is bonded to the first optical unit 11 at the lens surface 12 of the first optical unit 11. Thus, since the composite optical element 10 according to the present embodiment includes the first optical unit 11 and the second optical unit 14 that also have glass power, the composite optical element that includes the optical unit made of resin. In contrast, it is possible to prevent deterioration of optical characteristics (light transmittance, light condensing rate, aberration, etc.) due to environmental changes such as temperature changes and humidity changes. In the following description, the second optical unit 14 is bonded to the composite optical element 10, and the side on which the surface is the “surface of the composite optical element 10” t

[0014] The composite optical element 10 according to the present embodiment is further shown. In the composite optical element 10, the second optical unit 12 is joined to the first optical unit 11 so that the optical axis thereof coincides with the optical axis of the first optical unit 11. The first optical part 11 also has the first glass force, the second optical part 14 is the second glass, and the glass transition temperature of the first glass is higher than the glass transition temperature of the second glass. . Therefore, even when the composite optical element 10 that works on the present embodiment is formed by bonding the second glass melted after forming the first optical part 11 to the first optical part 11 as described later, Changes in the shape of the first optical unit 11 during bonding can be minimized.

In the first optical unit 11, the lens surface 13 is smooth without steps or ridges. Meanwhile, Ren The first uneven surface portion 12a is present around the optical axis, and the first smooth surface portion 12b is present on the periphery of the first uneven surface portion 12a. Therefore, when the compound optical element 10 is viewed from the front side (when the compound optical element 10 is also viewed from the downward force in FIG. 1), the center of the lens surface 12 (around the optical axis) is a force that is uneven by the first uneven surface portion 12a. The periphery of the surface 12 is smooth by the first smooth surface portion 12b, and the first uneven surface portion 12a and the first smooth surface portion 12b are arranged concentrically around a point on the optical axis of the composite optical element 10. The first concavo-convex surface portion 12a is a diffractive portion. Specifically, the first concavo-convex surface portion 12a has a plurality of concavities and convexities having a sawtooth cross section. In addition, it is more preferable that the circumference of the optical axis is within the area of radius dZ3, which is preferably within the area of radius dZ4, centered on one point on the optical axis, where d is the radius of the lens surface. More preferably, it is within the region of radius dZ2.

In the second optical unit 14, the lens surface (second optical function surface) 15 exists on the opposite side of the cemented surface 16. On the lens surface 15, the second smooth surface portion 15b exists around the optical axis, and the second uneven surface portion 15a exists on the periphery of the second smooth surface portion 15b. Therefore, when the composite optical element 10 is viewed from the front side (when the composite optical element 10 is viewed from below in FIG. 1), the center of the lens surface 15 (around the optical axis) is smoother by the second smooth surface portion 15b. The periphery of the lens surface 15 is uneven by the second concave convex surface portion 15a. The second concavo-convex surface portion 15a is a turning portion like the first concavo-convex surface portion 12a. Specifically, the second concavo-convex surface portion 15a has a plurality of concavities and convexities having a sawtooth cross section. Therefore, the arrangement relationship between the second uneven surface portion 15a and the second smooth surface portion 15b on the lens surface 15 of the second optical portion 14 is the same as the first uneven surface portion 12a and the first smooth surface portion on the lens surface 12 of the first optical portion 11. The arrangement relationship with 12b is the opposite. In other words, when the composite optical element 10 according to the present embodiment is viewed from the front surface side, the first uneven surface portion 12a exists on the back surface side of the second smooth surface portion 15b, and the first uneven surface surface of the second uneven surface portion 15a has the first surface. A smooth surface portion 12b is present. Thereby, on the surface of the composite optical element 10, the optical power differs between the periphery of the optical axis and the periphery rather than the periphery of the optical axis.For example, light having a wavelength is incident on the second smooth surface portion 15b to be condensed, Wavelength (≠ λ

1 2

) Can be incident on the second uneven surface portion 15a and condensed.

FIGS. 2A to 2D are schematic cross-sectional views showing a molding process of the composite optical element 10 according to the present embodiment. In the molding method of the composite optical element 10 according to the present embodiment, the first optical part 11 is molded through the steps shown in FIGS. 2 (a) and 2 (b), and then the processes shown in FIGS. ) The second optical unit 14 is bonded to the first optical unit 11 through a process. Specific examples are shown below.

First, as shown in FIG. 2 (a), a first glass preform 1 and a molding apparatus are prepared.

The first glass preform 1 preferably has a shape very similar to the shape of the first optical part 11. The molding apparatus includes an upper mold 81 and a lower mold 82, and the upper mold 81 and the lower mold 82 have molding surfaces 81a and 82a that become lens surfaces 12 and 13, respectively. The molding surface 81a is formed smoothly. Concavities and convexities corresponding to the first uneven surface portion 12a are formed in the center of the molding surface 82a, and the periphery of the molding surface 82a is smoothly formed so as to correspond to the first smooth surface portion 12b. Then, after setting the lower mold 82 with the molding surface 82a facing upward, the first glass preform 1 is set on the molding surface 82a, and the molding surface 81a is directed downward on the first glass preform 1. Set type 81.

Next, the first glass preform 1 is heated to near the glass softening temperature and pressed as shown in FIG. 2 (b) to form the molding surfaces 81a, 81a of the upper mold 81 and the lower mold 82. Transfer 82a onto the surface of the first glass preform 1 respectively. When pressing, the upper mold 81 and the lower mold 82 are pressed against each other by pressing the upper mold 81 against the surface of the first glass preform 1 and pressing the lower mold 82 against the surface of the first glass preform 1 respectively. 1It may be pressed against the surface of glass preform 1. Then, it is cooled. As a result, the first optical unit 11 can be molded. In this way, the first optical part 11 is molded using the press molding method. Unlike the molding of the first optical part using the polishing method or the grinding method, the first optical part 11 is molded by one molding. In addition, even if the lens surfaces 12 and 13 are aspherical surfaces, they can be molded relatively easily by processing the molding surfaces 81a and 82a. Therefore, the first optical unit 11 can be manufactured with a high manufacturing yield.

Next, as shown in FIG. 2 (c), a second glass preform 4 and a molding apparatus are prepared. The second glass preform 4 is made of glass having a glass transition temperature lower than that of the first glass preform 1. The molding apparatus includes an upper mold 81 and a lower mold 91, and the lower mold 91 has a molding surface 9la. The center of the molding surface 91a is smoothly formed so as to correspond to the second smooth surface portion 15b, and irregularities are formed on the periphery of the molding surface 91a so as to correspond to the second uneven surface portion 15a. Then, after setting the lower die 91 with the molding surface 91a facing upward, the second glass preform 4 Is set on the molding surface 91a, and the first optical part 11 and the upper die 91 are set on the second glass preform 4 in this order. When setting the first optical unit 11, if the first optical unit 11 is set so that the center of the lens surface 12 of the first optical unit 11 overlaps the center of the molding surface 91a of the lower die 91, the second optical unit 14 The composite optical element 10 can be molded by aligning the optical axis of the first optical unit 11 with the optical axis of the first optical unit 11.

Then, the second glass preform is heated to near the glass softening temperature and pressed as shown in FIG. 2 (d). At this time, since the glass transition temperature of the second glass preform is lower than the glass transition temperature of the first glass preform, the softness of the first optical unit 11 is reduced when the second glass preform is soft. Can be prevented. Further, since the second glass preform flows in accordance with the shape of the lens surface 12 and enters the concave portion at the peripheral edge of the molding surface 9 la, the peripheral shape is suitably transferred to the surface of the second glass preform 4. In this way, the composite optical element 10 that can be applied to the present embodiment can be molded.

[0022] As described above, in the composite optical element 10 according to the present embodiment, since both the first optical unit 11 and the second optical unit 14 have glass power, the composite optical unit having an optical unit made of resin is used. Excellent optical characteristics compared to optical elements. In addition, since the glass transition temperature of the first glass is higher than the glass transition temperature of the second glass, the second optical unit 14 can be bonded without any change in the shape of the first optical unit 11. Furthermore, in the composite optical element 10 according to the present embodiment, the optical power is different between the surface and the periphery of the composite optical element 10, so that the light can be fluorescent with different wavelengths.

Such a composite optical element 10 can be mounted on an optical device such as an imaging device, an illumination device, and an optical disc recording / reproducing device. The imaging device is a device for photographing a subject, for example, a digital still camera or a digital video camera. The illumination device is a device for irradiating light on an object to be illuminated, for example, a projector. In addition, optical disc recording / playback devices include digital versatile discs (hereinafter referred to as DVDs), compact discs (hereinafter referred to as CDs), and Blu-ray discs (registered trademarks, hereinafter referred to as BDs (registered trademarks)). It is a device that records and reproduces. In general, DVD, CD, and BD (registered trademark) have different wavelengths of light sources for recording and playback, optical disc thickness, etc., so DVD, CD, and BD (registered trademark) can be Record playback In order to make this possible, it is necessary to devise an optical system. However, if the composite optical device 10 that is effective in this embodiment is used, an optical disk recording / reproducing apparatus compatible with multiple types of information recording media can be realized. can do.

[Embodiment 2 of the Invention]

FIG. 3 is a schematic sectional view of the composite optical element 20 according to the second embodiment. In the composite optical element 20 that works in the present embodiment, unlike the composite optical element in the first embodiment, the first uneven surface portion 12a exists on the periphery of the lens surface 12 of the first optical portion 11, and the second uneven surface Surface 15a exists around the optical axis!

[Embodiment 3 of the Invention]

FIG. 4 is a schematic cross-sectional view of the composite optical element 30 according to the third embodiment. In the composite optical element 30 according to the present embodiment, unlike the composite optical element 10 in the first embodiment, each of the first optical part 31 and the second optical part 34 has a flat plate shape, and the first uneven surface part 32. Each of a and the second uneven surface portion 35a is formed with a plurality of uneven portions having a stepped cross section.

Specifically, in the first optical unit 31, the first uneven surface portion 32a is present around the optical axis, and the first smooth surface portion 32b is present at the periphery of the first uneven surface portion 32a. On the other hand, the second optical unit 34 has a lens surface 35 on the side opposite to the cemented surface 36. In the lens surface 35, the second smooth surface portion 35b exists around the optical axis, and the second uneven surface portion 35a exists on the periphery of the second smooth surface portion 35b. As in the first embodiment, on the lens surface 32, the first uneven surface portion 32a and the first smooth surface portion 32b are arranged concentrically around one point on the optical axis of the composite optical element 30, and the lens surface In 35, the second uneven surface portion 35a and the second smooth surface portion 35b are arranged concentrically around a point on the optical axis of the composite optical element 30.

When a parallel light beam is incident from the surface side of such a composite optical element 30, the phase of the light beam incident on the second smooth surface portion 35b is converted in the first uneven surface portion 32a. On the other hand, the light beam incident on the second uneven surface portion 35a is incident on the first smooth surface portion 3 lb after the phase is converted in the second uneven surface portion 35a.

<< Embodiment 4 of the Invention >>

FIG. 5 is a schematic sectional view of the composite optical element 40 according to the fourth embodiment. The composite optical element 40 according to the present embodiment has a configuration very similar to the composite optical element 30 of the third embodiment. However, the first uneven surface portion 42a of the first optical portion 41 and the second uneven surface portion 45a of the second optical portion 44 are lens array portions. Specifically, a plurality of concave lenses are arranged on each of the first uneven surface portion 42a and the second uneven surface portion 45a. Here, the first uneven surface portion 42a exists around the optical axis. In addition, a lens surface 45 exists on the opposite side of the second optical unit 44 from the joint surface 46, and the lens surface 45 has a second smooth surface portion 45b around the optical axis. The second uneven surface portion 45a is present at the periphery of 45b.

[0029] When a parallel light beam is incident from the surface side of such a composite optical element 40, the light beam incident on the second smooth surface portion 45b is emitted with the phase converted at the first uneven surface portion 42a. On the other hand, the light beam incident on the second uneven surface portion 45a is incident on the first smooth surface portion 42b after the phase is converted in the second uneven surface portion 45a.

[0030] It should be noted that a plurality of convex lenses may be arranged on each of the first uneven surface portion 42a and the second uneven surface portion 45a.

[Embodiment 5 of the Invention]

FIG. 6 is a schematic cross-sectional view of a composite optical element 50 according to the fifth embodiment. The composite optical element 50 according to the present embodiment has a configuration similar to that of the composite optical element 10 of the first embodiment, but the first uneven surface portion 52a of the first optical unit 51 and the first optical unit 54 of the second optical unit 54. 2 The uneven surface portion 55a is a phase step portion. Specifically, each of the first uneven surface portion 52a and the second uneven surface portion 55a is formed with a plurality of phase step surfaces having a stepped cross section. Here, the first uneven surface portion 52 a exists around the optical axis of the lens surface 52 of the first optical portion 51. In addition, a lens surface 55 exists on the opposite side of the second optical unit 54 from the cemented surface 56. The lens surface 55 has a second smooth surface portion 55b around the optical axis. The second uneven surface portion 55a exists on the periphery of the surface portion 55b.

When a parallel light beam is incident from the surface side of such a composite optical element 50, the light beam incident on the second smooth surface portion 55b that is the same as the composite optical element 30 of the third embodiment has a phase at the first uneven surface portion 52a. The phase of the light beam incident on the second uneven surface portion 55a is converted in the second uneven surface portion 55a.

[Embodiment 6 of the Invention]

FIG. 7 is a schematic cross-sectional view of a composite optical element 60 according to the sixth embodiment. In this embodiment The composite optical element 60 has a configuration very similar to that of the composite optical element 10 of the first embodiment, but the first uneven surface portion 62a of the first optical unit 61 and the second uneven surface portion 65 of the second optical unit 64. a is an antireflection part. Specifically, the first concavo-convex surface portion 62a and the second concavo-convex surface portion 65a are formed with a plurality of cone-shaped projections, and the cone-shaped projections are arranged at a pitch less than the wavelength of the light to be reflected. Has been. Here, the first uneven surface portion 62a exists around the optical axis of the lens surface 62 of the first optical portion 61. A lens surface 65 exists on the opposite side of the cemented surface 66 of the second optical unit 64. In the lens surface 65, a second smooth surface portion 65b exists around the optical axis. The second uneven surface portion 65a is present at the periphery of the surface portion 65b.

When a parallel light beam is incident from the surface side of such a composite optical element 60, the light beam incident on the second smooth surface portion 65b is prevented from being reflected on the first uneven surface portion 62a, and is incident on the second uneven surface portion 65a. The reflected light beam is prevented from being reflected at the second uneven surface portion 65a.

<< Other Embodiments >>

Embodiments 1 to 6 may have the following configuration.

[0036] Although a composite lens has been described as an example of a composite optical element, the composite optical element may be a composite mirror without being limited to a composite lens. When the composite optical element is a composite mirror, the optical functional surface may be a reflective surface.

[0037] The force that the lens surface of the first optical unit is aspherical may be a flat surface as in Embodiments 3 and 4, or may be a spherical surface, a cylindrical surface, an elliptical surface, and a toric surface. Good.

[0038] The first optical part is not limited to one formed by a press molding method, and may be one formed by etching or one formed by injection molding.

[0039] Although the lens surface of the first optical unit and the lens surface of the second optical unit are each formed with one type of uneven surface portion, multiple types of uneven surface portions may be formed.

[0040] The third optical unit may be bonded to the lens surface of the second optical unit. It is preferable that a third uneven surface portion is formed on the lens surface of the third optical portion (the portion on the side opposite to the cemented surface)! /.

[0041] Although the second optical unit is bonded to one of the two lens surfaces of the first optical unit, the fourth optical unit may be bonded to the other lens surface. . In this case, the fourth concavo-convex surface portion is formed on the lens surface of the fourth optical portion (the portion opposite to the cemented surface). I prefer to do that!

[0042] In Embodiments 3 to 6, as in Embodiment 2 above, the first uneven surface portion is present at the periphery of the optical axis of the lens surface of the first optical portion, and the second uneven surface portion is the first uneven surface portion. 2 It exists around the optical axis of the lens surface of the optical part.

[0043] Although the second uneven surface portion is also a diffractive portion if the first uneven surface portion is a diffractive portion, for example, the first uneven surface portion may be a diffractive portion and the second uneven surface portion may be a lens array portion.

Industrial applicability

As described above, the present invention can be mounted on an optical disc recording / reproducing apparatus, and in addition, an image pickup apparatus (digital still camera, digital video camera, etc.) and a display apparatus (projector, etc.) It can be installed.

Claims

The scope of the claims

[1] a first optical part having a first optical functional surface and made of glass;

A second optical part made of glass and bonded to the first optical part on the first optical functional surface;

The second optical unit has a bonding surface where the second optical unit is bonded to the first optical unit, and a second optical functional surface existing on the opposite side of the bonding surface,

A first uneven surface portion is present on at least a portion of the first optical functional surface, and a second uneven surface portion is present on at least a portion of the second optical functional surface. Optical element.

[2] The first optical unit is made of a first glass,

The second optical part is made of a second glass,

2. The composite optical element according to claim 1, wherein the glass softening temperature of the first glass is higher than the glass softening temperature of the second glass.

[3] Each of the first and second concavo-convex surface portions is at least one of a diffractive portion, a lens array portion having a plurality of concave or convex lens surface forces, a phase step portion, and a light reflection preventing portion. The composite optical element according to claim 1, wherein: