TWI589934B - Optical lens - Google Patents

Description

optical lens

This invention relates to an optical lens, and more particularly to a diffractive optical lens having a diffractive optical structure.

In recent years, with the evolution of the electronics industry and the vigorous development of industrial technology, the design of various electronic devices has gradually developed toward a light and easy to carry, so that users can be used for mobile commerce, entertainment or leisure whenever and wherever. For example, a wide variety of image capturing devices are widely used in various fields, such as portable electronic devices such as smart phones and wearable electronic devices, which have the advantages of small size and convenient carrying, and the user can When you need it, you can take it out and upload it and store it, or upload it to the Internet through the mobile network. It not only has important commercial value, but also adds color to the daily life of the general public.

In view of this, the optical lens applied to the image capturing device is also shrinking in size, and not only the thickness of the lens is required to be thinner, but also the diameter of the lens is required to be smaller. Please refer to FIG. 1 , which is a partial cross-sectional view of a conventional optical lens. It can be seen from the cross-sectional view shown in Fig. 1 that the assembly process of the optical lens 9 is cumbersome, for example The plurality of lenses 91 constituting the optical lens 9 must be mounted and fixed in the barrel 93 by means of an additional structural member 92, and for example, a stray light baffle must be provided in the lens barrel 93. 94 prevents stray light from passing through the lens 91, which obviously makes the optical lens 9 less susceptible to miniaturization. In addition, since most of the lenses 91 are formed by a process of injection molding, warping deformation or residual stress generated during molding is easy, which also increases the difficulty of assembly.

In particular, in order to improve the reliability of the miniaturized optical lens 9, there are many assembly-related details that need to be taken into account, for example: (1) How to improve the lens 91 after being assembled to the lens barrel 93 Structural strength; (2) How to pre-modify or avoid the warping deformation or residual stress generated by the lens 91 during the molding process, so as to facilitate the assembly of the subsequent optical lens 9 and avoid the optical path variation caused by the refractive index being changed. Causing unnecessary or sudden aberrations, and (3) how to simplify the composition of the optical lens 9 (such as the stray optical stop 93 or the structural member 92 for fixing the lens 91 to the lens barrel 93) to reduce the optical lens 9 assembly process.

Furthermore, a diffractive lens has been proposed for use in the optical lens 9 to improve imaging quality, such as correcting aberrations or eliminating dispersion. Please refer to FIG. 2 and FIG. 3 . FIG. 2 is a schematic diagram showing the appearance of a conventional diffractive optical lens, and FIG. 3 is a cross-sectional view of the diffractive optical lens shown in FIG. 2 . As can be seen from Fig. 2 and Fig. 3, the appearance of the diffractive optical lens 8 is not much different from that of the general lens 91, but a diffraction is formed therein for modulating the beam passing through the diffractive optical lens 8. The grating 81 is used to further correct aberrations or eliminate dispersion.

However, the above-mentioned diffractive optical lens 8 is only a simple lens structure, that is, the overall structure is an effective optical application area, so if the diffractive optical lens 8 is to be applied For the miniaturized optical lens, the above assembly-related details still need to be taken into consideration. For example, the diffractive optical lens 8 must be mounted and fixed in the lens barrel of the optical lens by using an additional structural member.

In addition, conventional diffractive optical lenses are limited by their usable wavelength range and are therefore limited in application. However, due to the increasing interest in optical technology products such as depth cameras, time of flight cameras (TOF cameras), infrared surveillance systems (CCTVs), and thermal imagers, The market scale is promising, and the wavelengths used in these optical technology products are mostly in a specific wavelength range, so the diffraction optical lens and its application have gradually gained attention.

Based on the above description, how to improve the structure and process of the diffractive optical lens itself to increase its usable wavelength range and avoid warping or residual stress during the molding process, and to simplify the optical through such improvement The structure of the lens and the structural strength of the diffractive optical lens after being assembled to the lens barrel, thereby facilitating the assembly and overall performance improvement of the subsequent optical lens, have become an important issue.

An object of the present invention is to provide an optical lens having a diffractive optical structure and a derivation structure, and the diffractive optical structure and the derivation structure are formed on the substrate of the optical lens through an imprint process or a spray process to avoid the optical lens. Warpage or residual stress is generated during the molding process, and at the same time, the composition of the device to which the optical lens is applied is simplified, thereby facilitating subsequent assembly.

In a preferred embodiment, an optical lens includes: a substrate having an optical application area and a derivative application area, and the derivative application area is located at a periphery of the optical application area; at least one derivative structure, Provided in the derivative application region; and a diffractive optical structure disposed in the optical application region and having at least one microstructure pattern for the light beam to pass therethrough to form a structure light and/or to improve at least one Optical defects.

In a preferred embodiment, the at least one optical defect comprises an aberration or a dispersion.

In a preferred embodiment, one of the optical lenses has a maximum thickness of less than 0.4 mm.

In a preferred embodiment, the refractive index of the diffractive optical structure, the at least one derivative structure, and at least two of the substrates differ by less than 5%.

In a preferred embodiment, the diffractive optical structure is formed on the substrate by an imprint process or a spray process.

In a preferred embodiment, the at least one derivative structure is formed on the substrate by an imprint process or a spray process.

In a preferred embodiment, the at least one derivative structure is assembled with a barrel, and the at least one derivative structure is used to lift the optical lens when the at least one derivative structure is assembled with the lens barrel. One of the structural strength and/or the reduction of stray light is diffused or incident in the direction of the optical application zone.

In a preferred embodiment, the at least one derivative structure comprises a stray light absorbing structure.

In a preferred embodiment, the at least one derivative structure includes an imitation Moth-Eye-like Structure or a type of photonic crystal structure.

In a preferred embodiment, the absorbance of the stray light absorbing structure is greater than 80%.

In a preferred embodiment, the at least one derivative structure includes a plurality of derivative structures, and the plurality of derivative structures are symmetrically arranged with the optical axis of the optical lens as an axis of symmetry.

In a preferred embodiment, the at least one derivative structure is used to provide a pointing indicator when the optical lens is mounted.

In a preferred embodiment, the optical lens system is applied to a shift axis optical system, and the at least one derivative structure includes a plurality of derivative structures; wherein the plurality of derivative structures are arranged asymmetrically.

In a preferred embodiment, the at least one derivation structure includes a plurality of protrusions, and the plurality of protrusions are centered on an optical center of the optical lens and periodically formed on the derivation application area.

In a preferred embodiment, one of the surfaces of the substrate is a flat surface or a curved surface, and the optical application area and the derivative application area are provided on the surface.

In a preferred embodiment, the substrate has a circular shape or a rectangular shape.

In a preferred embodiment, the substrate is a prism or a polygonal block.

In a preferred embodiment, the substrate has at least one perforation, and the at least one perforation has at least one microstructure around it to break the edge diffraction interference generated by the beam after being incident on the periphery of the at least one perforation ( Edge diffraction).

In a preferred embodiment, the optical lens is coated with at least one of an anti-reflection coating and a high reflection coating.

In a preferred embodiment, one of the antireflective films has a transmittance of greater than 95%.

1A‧‧‧ optical lens

1B‧‧‧ optical lens

1C‧‧‧ optical lens

1D‧‧‧ optical lens

1E‧‧‧ optical lens

1F‧‧‧ optical lens

9‧‧‧Optical lens

11‧‧‧Substrate

11D‧‧‧Substrate

11F‧‧‧Substrate

12‧‧‧Derivative structure

12*‧‧‧Derivative structure

12D‧‧‧ derivative structure

12E‧‧‧Derivative structure

13‧‧‧Diffractive optical structure

13*‧‧‧Diffractive optical structure

14‧‧‧Anti-reflective film

15‧‧‧High reflective film

16‧‧‧Microstructure

91‧‧‧ lens

92‧‧‧Structural parts

93‧‧‧Mirror tube

94‧‧‧Stray light file

111‧‧‧Optical application area

112‧‧‧Derivative Zone

113‧‧‧Perforation

131‧‧‧Microstructure pattern

Figure 1 is a cross-sectional view showing a portion of a conventional optical lens.

Figure 2 is a schematic view showing the appearance of a conventional diffractive optical lens.

Figure 3 is a schematic cross-sectional view of the diffractive optical lens of Figure 2.

4 is a schematic view showing the appearance of an optical lens of the present invention in a first preferred embodiment.

Figure 5 is a top conceptual view of the substrate of the optical lens of Figure 4.

Fig. 6 is a schematic cross-sectional view showing the optical lens shown in Fig. 4.

Figure 7 is a side view conceptual view of an optical lens of the second preferred embodiment of the optical lens of the present invention.

Figure 8 is a side view conceptual view of an optical lens of a third preferred embodiment of the optical lens of the present invention.

Figure 9 is a side view conceptual view of an optical lens of a fourth preferred embodiment of the optical lens of the present invention.

Figure 10 is a top conceptual view of an optical lens of a fifth preferred embodiment of the optical lens of the present invention.

Figure 11 is a top conceptual view of an optical lens of a sixth preferred embodiment of the optical lens of the present invention.

Please refer to FIG. 4 to FIG. 6. FIG. 4 is a schematic view showing the appearance of an optical lens according to a first preferred embodiment of the present invention, and FIG. 5 is a top view conceptual view of the substrate of the optical lens shown in FIG. 4 is a schematic cross-sectional view of the optical lens shown. The optical lens 1A includes a substrate 11, a derivative structure 12, and a diffractive optical structure 13. The substrate 11 can be made of glass material, plastic material or semiconductor component, but not limited thereto, and one side surface includes optical An application area (effective optical area) 111 and a derivative application area 112, and the derivative application area 112 is located at the periphery of the optical application area 111; wherein the derivative structure 12 is disposed in the derivative application area 112, and the diffraction optical structure 13 is disposed in the optical application The region 111 has a microstructure pattern 131 for forming a structure light through which a light beam passes, or for improving optical defects such as correction of aberration or dispersion. Furthermore, the optical performance in the usable wavelength range of the optical lens 1A can be enhanced by designing the microstructure pattern 131 of the diffractive optical structure 13.

In addition, although the substrate 11 shown in FIG. 4 to FIG. 6 has a circular plate shape, the surface including the optical application area 111 and the derivative application area 112 is a plane, and the optical operation area 111 has a circular shape, but this is not For example, the surface including the optical application area 111 and the derivative application area 112 may also be a curved surface, or the substrate 11 may be designed into any shape according to actual application requirements, such as a rectangular plate shape, a triangular pyramid shape or Irregular shape, can also be designed according to the actual application needs to make the optical application area 111 It is rectangular, elliptical or irregular.

Furthermore, in the preferred embodiment, the derivative structure 12 is assembled with a barrel (not shown), so that the optical lens 1A can be mounted and fixed in the lens barrel. The housing structure of any of the devices to which the optical lens 1A is applied, such as the lens barrel of the optical lens, and the derivation structure 12 contributes to the structural strength of the optical lens 1A when the optical lens 1A is mounted and fixed in the lens barrel. And can reduce the stray light diffusion or incident in the direction of the optical application area 111.

Preferably, but not limited thereto, the derivatization structure 12 further comprises a stray light absorbing structure having an absorption ratio greater than 80%, such as a Moth-Eye-like structure and/or a photonic crystal. The structure is mainly for absorbing unnecessary stray light; wherein, when the derivation structure 12 includes both a moth-like structure and a photonic crystal-like structure, the moth-eye structure and the photonic crystal-like structure may be partially connected to each other. Overlap or fully overlap.

Moreover, in the preferred embodiment, at least one of the diffractive optical structure 13 and the derivative structure 12 is formed on the substrate 11 through an imprint process or a spray process, and the diffractive optical structure 13 and the derivative are derived. The structure 12 can be formed on the substrate 11 separately depending on the actual application requirements, or can be simultaneously formed on the substrate 11 in a single imprint process or a spray process. In particular, since the diffractive optical structure 13 and the derivation structure 12 are formed on the substrate 11 through an imprint process or a spray process, the overall thickness of the optical lens 1A can be effectively thinned, and the optical body of the present invention The lens 1A is not formed by a process of injection molding, so that warping deformation or residual stress is not easily generated during molding.

Preferably, but not limited thereto, the imprint process and the spray process are respectively a nanoimprint process and a nano spray process, and the optical lens 1A is the most The large thickness is less than 0.4 mm (mm); wherein the refractive index of the diffractive optical structure 13, the derivative structure 12, and the substrate 11 should be less than 5%, to avoid unnecessary generation of the light beam passing through the optical lens 1A. Multiple reflections or refractions, thereby reducing design complexity and avoiding stray light.

In addition, how to improve the aberration or the structural light passing through and outputting the microstructured pattern 131 of the diffractive optical structure 13 according to the user's needs, and how to design the diffraction pattern 131 of the optical structure 13 to improve the aberration or Optical defects such as dispersion, and how to perform structural analysis on the structural structure 12 to perform structural design, thereby improving the structural strength of the optical lens 1A when it is mounted and fixed in the lens barrel, are known to those skilled in the art. I understand that it will not be repeated here.

Please refer to FIG. 7, which is a side view conceptual view of an optical lens according to a second preferred embodiment of the present invention. The optical lens 1B of the preferred embodiment is substantially similar to that described in the foregoing first preferred embodiment, and will not be further described herein. The difference between the preferred embodiment and the first preferred embodiment is that the optical lens 1B is further coated with an anti-reflection coating 14 and a high reflection coating 15 and is resistant. The reflective film 14 is located between the diffractive optical structure 13 and the high-reflection film 15; wherein the transmittance of the anti-reflection film 14 is greater than 95%, and the diffractive optical structure 13, the anti-reflection film 14, and the high-reflection film 15 are mutually They may overlap completely or at least partially, such that when a plurality of optical lenses including the optical lens 1B are assembled together, the overall stray light and ghosting can be eliminated or reduced. However, the above is only one embodiment, and the transmittance of the anti-reflection film 14 is not limited to the above, and those skilled in the art can uniformly change the design of the diffractive optical structure 13, the anti-reflection film 14 and the high according to the actual application requirements. The positional relationship of the reflective film 15.

Please refer to FIG. 8, which is a side view conceptual view of an optical lens according to a third preferred embodiment of the present invention. The optical lens 1C of the preferred embodiment is substantially similar to that described in the foregoing first preferred embodiment, and will not be further described herein. The difference between the preferred embodiment and the first preferred embodiment is that the other side surface of the substrate 11 also includes an optical application area on which the other diffractive optical structure 13* is disposed, and another a derivative structure on which the derivative structure 12* is disposed; wherein the microstructure patterns on the two diffractive optical structures 13, 13* respectively located on both sides of the substrate 11 may be the same or different, depending on actual application requirements. And was designed.

Please refer to FIG. 9, which is a side view conceptual view of an optical lens according to a fourth preferred embodiment of the present invention. The optical lens 1D of the preferred embodiment is substantially similar to that described in the foregoing first preferred embodiment, and will not be further described herein. The difference between the preferred embodiment and the first preferred embodiment is that the substrate 11D is a prism, and a surface of the crucible has a diffraction optical structure 13 disposed thereon. The optical application area and the derivative application area on which the derivative structure 12D is disposed. Of course, the above is only one embodiment, the substrate 11D is not limited to 稜鏡, and the substrate may be any polygonal block.

Please refer to FIG. 10 , which is a top view conceptual view of an optical lens according to a fifth preferred embodiment of the present invention. The optical lens 1E of the preferred embodiment is substantially similar to that described in the foregoing first preferred embodiment, and will not be further described herein. The difference between the preferred embodiment and the first preferred embodiment is that a plurality of derivative structures 12E are formed on the derivation area 112 of the substrate 11, and the derivation structures 12 are optical axes of the optical lens 1E. 16 is symmetrically arranged as a symmetry axis; and in the preferred embodiment, the derivative structures 12E are a plurality of convex portions, and are formed with the optical center of the optical lens 1E as a center and periodically (equally spaced) In Yan The student uses the area 112.

However, the above is only an embodiment, and is not limited thereto; for example, in a specific case, such as the optical lens 1E is applied to a shift axis optical system, the derivative structures 12E can be changed in design. Arranged symmetrically to further adjust the optical path of at least a portion of the light beam incident on the optical lens 1E.

Furthermore, it is additionally noted that the derivative structures of the various embodiments described above are also capable of providing a pointing indication when the optical lens is mounted. In particular, in some cases, the diffractive optical structure is directional, so that the directionality of the diffractive optical structure can be used to form a mark on a specific portion of the derivative structure, or the directionality of the optical structure can be diffracted. The arrangement of a plurality of derivative structures is designed to guide the optical lens to be correctly mounted, thereby simplifying the process and man-hour of mounting the optical lens.

Please refer to FIG. 11 , which is a top view conceptual view of an optical lens according to a sixth preferred embodiment of the present invention. The optical lens 1F of the preferred embodiment is substantially similar to that described in the foregoing first preferred embodiment. For example, the substrate 11F still has an optical application for the diffraction optical structure (not shown) disposed thereon. The area 111 and the derivative operation area 112 on which the derivative structure (not shown) is disposed are not described herein. The difference between the preferred embodiment and the first preferred embodiment is that the substrate 11F further has a plurality of through holes 113, and at least one of the through holes 113 is provided with a plurality of microstructures 16 to destroy the light beam incident thereon. The edge generated by at least one of the perforations 113 is edge diffraction.

In combination with the description of the above preferred embodiments, the optical lens of the present invention has the following advantages: (1) since the diffractive optical structure and the derivative structure are formed on the substrate through an imprint process or a spray process, the optical lens can be used. The overall thickness is effectively thinned; (2) the microstructure pattern on the diffractive optical structure can be designed to enhance Optical performance in the available wavelength range of the optical lens; (3) Since the optical lens of the present invention is not formed by the process of injection molding, warping deformation or residual stress is not easily generated during the molding process, thereby facilitating subsequent assembly. And avoiding unnecessary or sudden aberrations caused by the change of the refractive index caused by the optical path variation; (4) since the optical lens itself has a derivative structure capable of absorbing stray light or reducing stray light diffusion, if it is applied to In the optical lens, it can replace the stray light baffle in the conventional optical lens, thereby simplifying the structure of the optical lens to facilitate miniaturization of the optical lens and reducing the assembly process of the optical lens; (5) The optical lens itself has a derivative structure which can be assembled with the lens barrel of the applied device, so that it can replace the mechanical member additionally provided for fixing the optical lens in the conventional device, thereby simplifying the composition of the optical lens. In order to miniaturize the optical lens and reduce the assembly process of the optical lens; at the same time, through the relevant mechanical division of the derivative structure And the structural design can improve the structural strength of the optical lens when it is mounted and fixed; and (6) the derivation structure of the optical lens can also provide a pointing indication when the optical lens is mounted, thereby simplifying the process of mounting the optical lens and Working hours.

The above are only the preferred embodiments of the present invention, and are not intended to limit the scope of the present invention. Therefore, any equivalent changes or modifications made without departing from the spirit of the present invention should be included in the present invention. Within the scope of the patent application.

1A‧‧‧ optical lens

11‧‧‧Substrate

12‧‧‧Derivative structure

13‧‧‧Diffractive optical structure

Claims (18)

An optical lens comprising: a substrate having a measurement surface having an optical application area and a derivative application area, wherein the derivative application area is located at a periphery of the optical application area; at least one derivative structure is disposed on the derivative An application area and including a stray light absorbing structure; wherein the stray light absorbing structure comprises a Moth-Eye-like structure or a photonic crystal structure; and a diffractive optical structure In the optical application area, and having at least one microstructure pattern for the light beam to pass therethrough to form a structure light and/or to improve at least one optical defect. The optical lens of claim 1, wherein the at least one optical defect comprises an aberration or a dispersion. The optical lens of claim 1, wherein one of the optical lenses has a maximum thickness of less than 0.4 mm. The optical lens of claim 1, wherein the refractive optical structure, the at least one derivative structure, and at least two of the substrates have a refractive index difference of less than 5%. The optical lens of claim 1, wherein the diffractive optical structure is formed on the substrate by an imprint process or a spray process. The optical lens of claim 1, wherein the at least one derivative structure is formed on the substrate by an imprint process or a spray process. The optical lens of claim 1, wherein the at least one derivative structure is assembled with a barrel, and the at least one derivative structure is assembled when the at least one derivative structure is assembled with the lens barrel. It is used to enhance the structural strength of one of the optical lenses and/or reduce the stray light diffusion or incident in the direction of the optical application area. The optical lens of claim 1, wherein the absorption coefficient of the stray light absorbing structure is greater than 80%. The optical lens of claim 1, wherein the at least one derivative structure comprises a plurality of derivative structures, and the plurality of derivative structures are symmetrically arranged with the optical axis of the optical lens as an axis of symmetry. The optical lens of claim 1, wherein the at least one derivative structure is for providing a pointing indicator when the optical lens is mounted. The optical lens of claim 1, wherein the optical lens is applied to a shift axis optical system, and the at least one derivative structure comprises a plurality of derivative structures; wherein the plurality of derivative structures are arranged asymmetrically. The optical lens of claim 1, wherein the at least one derivative The structure includes a plurality of convex portions, and the plurality of convex portions are formed on the derivative application region with the optical center of one of the optical lenses as a center and equally spaced. The optical lens of claim 1, wherein one surface of the substrate is a plane or a curved surface, and the optical application area and the derivative application area are provided on the surface. The optical lens of claim 1, wherein the substrate has a circular shape or a rectangular shape. The optical lens of claim 1, wherein the substrate is a prism or a polygonal block. The optical lens of claim 1, wherein the substrate has at least one perforation, and the at least one perforation has at least one microstructure around it to break the light beam generated after being incident on the periphery of the at least one perforation. The edge is diffracted by edge diffraction. The optical lens of claim 1, wherein the optical lens is coated with at least one of an anti-reflection coating and a high reflection coating. The optical lens of claim 17, wherein one of the antireflection films has a transmittance of greater than 95%.