TW202045976A - Optical imaging apparatus with adjustable focal length - Google Patents

Abstract

An optical imaging apparatus with an adjustable focal length comprises a plurality of optical lenses. The optical lenses are arranged in an optical axis to capture an image in an image capturing direction and project the image on a hypothesis imaging plane. The optical lenses are at least divided into at least one fixed lens set and at least one movable lens set; wherein the fixed lens set is disposed in a fixed manner and the movable lens set is adapted to move with respect to the fixed lens set, so as to adjust the focal length of the optical lenses.

Description

Optical imaging device

The present invention relates to the configuration of optical lens groups, in particular to an optical imaging device.

As shown in Fig. 1 and Fig. 2, the optical lens group of the photographing device is composed of a plurality of optical lenses arranged in sequence along an optical axis L to obtain a longer effective focal length (Effect Focal Length, EFL) in a limited space. ) To image on an imaging plane I. The imaging plane I is an imaginary plane for setting the image sensor 140'. The multiple optical lenses of the aforementioned optical lens group are usually fixed on a lens frame to form a single optical lens group 120'.

As shown in Figures 1 and 2, when the object distance changes, the aforementioned optical lens set 120' needs to be shifted back and forth to change the back focal length to focus on the object, so that objects with different object distances can be clearly imaged on Imaging surface I. Or, when the photographing device is unstable, the optical lens group 120' moves up and down, left and right to perform optical image stabilization (OIS). The optical lens group 120' composed of a plurality of optical lens groups is heavy, and requires a voice coil motor (VCM) or other actuating elements 130' to drive displacement. Portable electronic devices such as smart phones or tablet computers are usually thin and light with limited internal space. The large-sized actuating element 130' occupies space, which is not conducive to arranging the optical lens group 120' in a portable electronic device with limited space. At the same time, the actuating element 130' with a large driving force consumes a large driving current, and will consume a large amount of power.

In view of the above problems, the present invention proposes an optical imaging device to reduce the amount of driving force required for adjusting optical characteristics.

In at least one embodiment of the present invention, the optical imaging device includes a plurality of optical lenses. The multi-learning lens is arranged along an optical axis to capture images in an image capturing direction and image on an imaging surface.

The optical lenses are divided into at least one fixed lens group and at least one movable lens group; wherein, the fixed lens group is a fixed set, and the movable lens group is used for displacement relative to the fixed lens group.

In at least one embodiment, the movable lens group is used to move back and forth on the optical axis relative to the fixed lens group.

In at least one embodiment, the movable lens group is used for displacement relative to the fixed lens group on a plane perpendicular to the optical axis.

In at least one embodiment, the optical imaging device further includes an image sensor located on the imaging surface.

In at least one embodiment, the optical imaging device further includes a filter between the optical lenses and the image sensor.

In at least one embodiment, the optical imaging device further includes a fixing frame, and the image sensor and the filter are arranged on the fixing frame.

In at least one embodiment, the optical imaging device further includes an actuating element connected to the movable lens group, and the actuating element is used to drive the movable lens group to move relative to the fixed lens group.

In at least one embodiment, the optical imaging device further includes a second lens frame for carrying the movable lens group, and the actuating element is connected to the second lens frame.

In at least one embodiment, the optical imaging device further includes a first lens frame for carrying and fixing the lens group.

In at least one embodiment, the actuating element is a voice coil motor, a memory metal motor, a piezoelectric motor, or a combination of two or more thereof.

In at least one embodiment, the optical imaging device further includes an optical path changing element located in the imaging direction of the optical lenses, and the optical path changing element is used to change the light traveling parallel to an actual imaging direction to parallel to the imaging direction March.

In at least one embodiment, the light path changing element is a reflective sheet, and an included angle is formed between the reflective sheet and the imaging direction.

In at least one embodiment, the light path changing element is a beam, the beam has a light incident surface and a light exit surface, the light entrance surface faces the actual image capturing direction, the light exit surface faces the optical lenses, and the light entrance surface and the light exit surface There is an angle between the faces.

In at least one embodiment, the optical imaging device has more than two fixed lens groups, and the effective focal lengths of each fixed lens group are different.

In at least one embodiment, the optical imaging device has more than two movable lens groups, and the effective focal lengths of the movable lens groups are different.

The present invention divides multiple optical lenses into multiple groups. When adjusting optical characteristics, such as focusing, zooming, and optical anti-shake, only the movable lens group among the plurality of optical lenses is moved. The weight of the movable lens group or the displacement stroke required to adjust the optical characteristics is smaller than the weight of the entire optical lens group or the required displacement stroke. Therefore, the driving force required to provide the actuating element for moving the movable lens group is less than the driving force required to move the entire optical lens group, which can effectively reduce the size of the actuating element, thereby reducing the overall size and weight of the optical imaging device . At the same time, because the driving force that the actuating element needs to provide is reduced, the driving current required by the actuating element can also be reduced, which improves the power consumption of the optical imaging device.

Please refer to FIG. 3 and FIG. 4, which are an optical imaging device 100 disclosed in the first embodiment of the present invention, which is used to capture images in an imaging direction C and to form images on an imaging surface I; the aforementioned imaging surface I is An imaginary plane.

Referring to FIGS. 3 and 4, the optical imaging device 100 includes a plurality of optical lenses, an actuating element 130, an image sensor 140 and a filter 150. The optical imaging device 100 is used to be installed in an electronic device; the electronic device can be, but is not limited to, a smart phone, a tablet computer, a notebook computer, a display, or a stand-alone camera.

As shown in FIG. 3 and FIG. 4, a plurality of optical lenses are arranged along an optical axis L to capture images toward the image capturing direction C, and the images are formed on the imaging surface I. The multiple optical lenses are divided into one or more fixed lens groups 110 and one or more movable lens groups 120; the first embodiment takes a fixed lens group 110 and a movable lens group 120 as an example, but the fixed The number of lens groups 110 and the number of movable lens groups 120 can be changed arbitrarily.

As shown in FIG. 3 and FIG. 4, the fixed lens group 110 is a fixed arrangement, and the movable lens group 120 is used for displacement relative to the fixed lens group 110. In the first embodiment, the movable lens group 120 is disposed between the fixed lens group 110 and the imaging surface I, and the back focal length of the multiple optical lenses to the imaging surface I can be changed to perform different object distances. Focusing, clear imaging on the imaging plane I; but the present invention does not exclude the position exchange of the fixed lens group 110 and the movable lens group 120; that is, the arrangement order of the fixed lens group 110 and the movable lens group 120 on the optical axis L is not Unrestricted, but can be changed at will.

As shown in FIGS. 3 and 4, relative to the fixed lens group 110, the movable lens group 120 can be displaced forwards and backwards on the optical axis L, or can be displaced up, down, left, and right on a plane perpendicular to the optical axis L. The direction in which the movable lens group 120 is displaced relative to the fixed lens group 110 depends on the function to be performed. When performing the focusing function, the movable lens group 120 is displaced back and forth on the optical axis L relative to the fixed lens group 110. When the optical anti-shake function is performed, the movable lens group 120 is displaced up, down, left, and right relative to the fixed lens group 110 on a plane perpendicular to the optical axis L. Of course, the aforementioned two functions can be performed at the same time, so that the movable lens group 120 performs three-axis movement.

As shown in FIG. 3, the image sensor 140 and the filter 150 constitute an image sensor module. The image sensor 140 is located on the imaging surface I, so that the imaging of multiple optical lenses can fall on the image sensor 140. The image sensor 140 performs image capture and encodes to generate an image signal. The filter 150 is located between the optical lenses and the image sensor 140 to adjust the wavelength distribution of the light entering the image sensor 140.

As shown in FIGS. 3 and 4, the actuating element 130 is directly or indirectly connected to the movable lens group 120, so that the movable lens group 120 is combined with the actuating element 130 to form an adjustment module. The actuating element 130 is used to drive the movable lens group 120 to move relative to the fixed lens group 110 to perform a focusing function or an optical anti-shake function. The actuating element 130 may be, but is not limited to, a voice coil motor (VCM), a shape memory alloy (SMA), a piezoelectric motor (Piezo), or a combination of two or more of them. The actuating element 130 may be a voice coil motor (VCM), a shape memory alloy (SMA), a piezoelectric motor (Piezo), or a combination of two or more of them. At the same time, taking the voice coil motor as an example, the number of coils in the voice coil motor can be configured according to requirements, so that the movable lens group 120 can move in a single axis on the optical axis L for focusing, and perform a two-axis linear movement perpendicular to the optical axis L to achieve Optical anti-shake, or simultaneous three-axis linear movement to achieve focus and optical anti-shake. In addition to the three-axis linear movement, the movable lens group 120 can also be appropriately tilted or rotated to correct the optical axis L through the configuration of the driving stroke difference between the opposite sides of the movable lens group 120.

As shown in FIG. 4, the fixed lens group 110, the actuating element 130, the filter 150 and the image sensor 140 are directly or indirectly fixed to a base 180, so that the fixed lens group 110, the adjustment module and the image sensor Modules can be assembled and connected in sequence. The base 180 can be an independent substrate, such as a printed circuit board, so that the optical imaging device 100 forms a single module to facilitate installation in an electronic device. The base 180 may also be a part of the housing 300 of the electronic device.

Referring again to FIG. 4, the optical imaging device 100 may further include a first lens frame 112, a second lens frame 122 and a fixing frame 160. The first lens frame 112 and the fixing frame 160 are disposed on the base 180, the first lens frame 112 carries the fixed lens group 110, and the image sensor 140 and the filter 150 are fixed to the fixing frame 160 so that the lens group 110, The filter 150 and the image sensor 140 are indirectly fixed to the base 180. The second lens frame 122 carries the movable lens group 120, and the actuating element 130 is connected to the second lens frame 122 and fixed to the base 180, so that the movable lens group 120 is indirectly connected to the actuating element 130. The aforementioned fixing structure is only an example, and the present invention does not limit the arrangement of the optical lenses, the actuating element 130 and the image sensor 140 in the aforementioned fixing structure. In some embodiments, the optical imaging device 100 may include a lens barrel, and the fixed lens group 110, the movable lens group 120, and the actuating element 130 are disposed in the lens barrel. In some embodiments, the fixed lens group 110 is arranged in one lens barrel, the movable lens group 120 and the actuating element 130 are arranged in another lens barrel, and the two lens barrels are connected to each other.

As shown in FIGS. 4 and 5, generally, the number of optical lenses in the fixed lens group 110 and the movable lens group 120 is to make the movable lens group 120 have a smaller weight as much as possible, so that a smaller driving force is required. The movable lens group 120 can be driven to move, so that the size of the actuating element 130 can be effectively reduced. Generally, the size of the multiple optical lenses in the long focal length optical lens group will be sequentially reduced, so that the optical lens at the imaging end will have a smaller weight; in this case, the optical lens close to the imaging surface I can be selected as the movable lens group 120 , So that the movable lens group 120 is located between the fixed lens group 110 and the imaging surface I, and the weight of the movable lens group 120 is smaller than that of the fixed lens group 110. The selection of this movable lens group 120 is only a solution and is not intended to limit the present invention Selection of the middle movable lens group 120.

As shown in Figure 5, when the optical lens group wants to focus, for example, when the shooting distance is changed from infinity to a short distance, the back focal length of the optical lens group to the imaging surface I needs to be changed to complete focusing and let The imaged image is clear. In the optical imaging device 100 in one or more embodiments of the present invention, it is only necessary to move the movable lens group 120 to change the back focal length for focusing without moving the entire optical lens group. Since the number of optical lenses and the space occupied by the movable lens group 120 are smaller than that of the entire optical lens group, the actuating element 130 can be reduced in weight or size, and the driving current required by the actuating element 130 can also be reduced.

The prior art uses FIG. 2 as an example, and FIG. 5 is an example of the present invention for comparison. The effective focal length (Effect Focal Length, EFL) of the movable lens group 120 is actually smaller than the effective focal length of the entire optical lens group. When the same focusing effect is achieved, the displacement stroke (the amount of change in back focal length) required to move the movable lens group 120 from the first position P1 to the second position P2 will be less than the initial displacement required to move the entire optical lens group for focusing Stroke ΔP.

In a small-sized portable electronic device, such as a mobile phone with a camera function or a portable photographing device, the imaging device usually has 5 to 8 optical lenses, and the effective focal length of these optical lenses is 20 to 35 mm. According to the optical imaging device 100 proposed in the present invention, the number of the movable lens group 120 can be configured to be composed of 3 to 4 optical lenses, and the effective focal length of the movable lens group 120 is configured to be less than 20 to 35 mm; in this case, the movable lens group is moved 120 for focusing, the displacement stroke required to move can be reduced.

Referring to Figure 2 and Figure 5, for example, when the effective focal length of the optical lens group is 26.6mm, and the object distance is changed from infinity to 1.2m, moving the entire optical lens group for focusing requires the initial The displacement stroke ΔP is 0.619mm. If the effective focal length of the optical lens group is still 26.6mm, but as shown in Figure 5, it is divided into a fixed lens group 110 with an effective focal length of 13.311mm and a movable lens group 120 with an effective focal length of -8.213mm, only movement is required to focus. The movable lens group 120, and the displacement stroke required for the movable lens group 120 to move from the first position P1 to the second position P2 can be reduced to 0.2 mm.

Please refer to FIG. 6 and FIG. 7, which show an optical imaging device 100 disclosed in the second embodiment of the present invention. The difference between the second embodiment and the first embodiment is that the optical imaging device 100 of the second embodiment further includes an optical path changing element 170, which is located in the imaging direction C of the optical lenses, and is used to parallel the actual imaging The light traveling in the direction C'changes to travel parallel to the imaging direction C. That is, the optical imaging device 100 may be configured as a periscope structure, so that the optical axis L of the optical lenses does not need to be arranged along the thickness direction of the electronic device, which is beneficial to the application in thin and light electronic devices.

As shown in FIG. 6, in a specific embodiment, the light path changing element 170 is a reflective sheet, and an included angle is formed between the reflective sheet and the imaging direction C. The angle between the imaging direction C and the reflective sheet and the angle between the actual image capturing direction C'and the reflective sheet are set to be the same, so that the light traveling through the window 310 of the electronic device housing 300 can change the traveling direction after passing through the reflective sheet The fixed lens group 110 and the movable lens group 120 are used to form an image on the image sensor 140.

As shown in FIG. 7, in a specific embodiment, the optical path changing element 170 is a beam. The beam has a light incident surface 172 and a light exit surface 174. The light incident surface 172 faces the actual imaging direction C', the light output surface 174 faces the multiple optical lenses, and there is an included angle between the light incident surface 172 and the light output surface 174 to change the light traveling along the actual imaging direction C'to Take the image direction C.

Referring to FIGS. 8 and 9, in the first embodiment and the second embodiment, the relative positions of the fixed lens group 110 and the movable lens group 120 can be changed in various ways. The optical path changing element 170 shown in the figure can be omitted when the imaging direction C and the actual imaging direction C'are the same.

As shown in FIG. 8, the movable lens group 120 can be located between the fixed lens group 110 and the imaging surface I, that is, the movable lens group 120 is located between the fixed lens group 110 and the image sensor 140. Therefore, when focusing, the optical lens group close to the image sensor 140 is moved to change the back focal length.

As shown in FIG. 9, the fixed lens group 110 may be located between the movable lens group 120 and the imaging surface I, that is, the fixed lens group 110 is located between the movable lens group 120 and the image sensor 140. Therefore, when focusing, the optical lens group away from the image sensor 140 is moved to change the front focal length.

Please refer to FIG. 10, which is an optical imaging device 100 disclosed in the third embodiment of the present invention. The optical imaging device 100 includes two fixed lens groups 110 and a movable lens group 120. The optical path changing element 170 shown in the figure can be omitted when the imaging direction C and the actual imaging direction C'are the same. The movable lens group 120 is located between the two fixed lens groups 110. When the movable lens group 120 moves, the optical lens group located in the middle section of the plurality of optical lenses moves. Therefore, the movable lens group 120 at this time can perform zooming. The aforementioned two fixed lens sets 110 do not need to have the same optical lens composition, nor do they need to have the same effective focal length.

As shown in FIG. 11, it is an optical imaging device 100 disclosed in the fourth embodiment of the present invention. The optical imaging device 100 includes a fixed lens group 110 and two movable lens groups 120. The optical path changing element 170 shown in the figure can be omitted when the imaging direction C and the actual imaging direction C'are the same. The fixed lens group 110 is located between the two movable lens groups 120. When focusing, the optical lens groups located in the front and back sections of the multiple optical lenses are moved while changing the front focal length and the back focal length. The aforementioned two movable lens groups 120 do not need to have the same optical lens composition, nor do they need to have the same effective focal length.

As shown in FIG. 12 and FIG. 13, it is an optical imaging device 100 disclosed in the fifth embodiment of the present invention. The optical imaging device 100 includes a plurality of fixed lens groups 110 and a plurality of movable lens groups 120. The optical path changing element 170 shown in the figure can be omitted when the imaging direction C and the actual imaging direction C'are the same. The arrangement of the fixed lens group 110 and the movable lens group 120 shown in the figure is only an example, and other arrangements are also possible. When focusing, only the movable lens group 120 needs to be moved, and it is not necessary to move all the optical lenses at the same time. In addition, among the multiple movable lens groups 120, it is also possible to move only the movable lens group 120 located between the two fixed lens groups 110 according to actual imaging requirements, so as to achieve the zoom effect, it is not necessarily the multiple movable lens groups 120. Move at the same time to focus or zoom. The aforementioned multiple movable lens groups 120 do not need to have the same optical lens composition, nor do they need to have the same effective focal length.

In one or more embodiments of the present invention, the number of the fixed lens group 110 and the movable lens group 120, or the arrangement order on the optical axis L can be changed arbitrarily, and is not limited to the number shown in FIGS. 8 to 13 And the order of arrangement. In particular, moving the movable lens group 120 at different positions can achieve different optical adjustment effects; for example, changing the front focal length or the back focal length can focus on objects with different object distances, while changing the movable lens The relative position between the group 120 and the two fixed lens groups 110 can be zoomed.

The present invention divides multiple optical lenses into multiple groups. When adjusting the optical characteristics, only the movable lens group 120 among the plurality of optical lenses is moved. The weight of the movable lens group 120 or the displacement stroke required to adjust the optical characteristics is smaller than the weight of the entire optical lens group or the required displacement stroke. Therefore, the driving force required to provide the actuating element 130 for moving the movable lens group 120 is less than the driving force required to move the entire optical lens group, which can effectively reduce the size of the actuating element 130, thereby reducing the size of the optical imaging device 100 Overall size and weight. At the same time, the driving force required by the actuating element 130 is reduced, so that the driving current required by the actuating element 130 can also be reduced, and the power consumption of the optical imaging device 100 is improved.

100: Optical imaging device 110: Fixed lens group 112: The first lens frame 120: movable lens group 120’: Optical lens group 122: second lens frame 130, 130’: Actuating element 140,140’: Image sensor 150: filter 160: fixed frame 170: Optical path changing element 172: Glossy Surface 174: Glossy Surface 180: Pedestal 300: shell 310: Window C: Take the image direction C’: Actual imaging direction I: imaging surface L: Optical axis P1: first position P2: second position ΔP: initial displacement stroke

Fig. 1 is a schematic top view of a photographing device in the prior art. FIG. 2 is a schematic diagram of the shift of the optical lens group for focusing in the prior art. 3 is a schematic top view of the optical imaging device in the first embodiment of the present invention. 4 is a schematic cross-sectional view of the optical imaging device in the first embodiment of the present invention. FIG. 5 is a schematic diagram of focusing by the optical imaging device in the first embodiment of the present invention. 6 is a schematic cross-sectional view of the optical imaging device in the second embodiment of the present invention. 7 is a schematic cross-sectional view of another optical imaging device in the second embodiment of the present invention. 8 and 9 are schematic diagrams of the arrangement of the fixed lens group and the movable lens group in the first and second embodiments of the present invention. 10 is a schematic diagram of the arrangement of the fixed lens group and the movable lens group in the third embodiment of the present invention. 11 is a schematic diagram of the arrangement of the fixed lens group and the movable lens group in the fourth embodiment of the present invention. 12 and 13 are schematic diagrams of the arrangement of the fixed lens group and the movable lens group in the fifth embodiment of the present invention.

100: Optical imaging device

110: Fixed lens group

120: movable lens group

130: Actuating element

140: image sensor

150: filter

C: Take the image direction

I: imaging surface

L: Optical axis

Claims (15)

An optical imaging device comprising: A plurality of optical lenses are arranged along an optical axis to capture images in an imaging direction and image on an imaging surface; the optical lenses are divided into at least one fixed lens group and at least one movable lens group; Wherein, the at least one fixed lens group is fixedly arranged, and the at least one movable lens group is used for displacement relative to the at least one fixed lens group. The optical imaging device according to claim 1, wherein the at least one movable lens group is configured to move back and forth on the optical axis relative to the at least one fixed lens group. The optical imaging device according to claim 1, wherein the at least one movable lens group is used to shift relative to the at least one fixed lens group on a plane perpendicular to the optical axis. The optical imaging device according to claim 1, further comprising an image sensor located on the imaging surface. The optical imaging device according to claim 4, further comprising a filter between the optical lenses and the image sensor. The optical imaging device according to claim 5, further comprising a fixing frame, and the image sensor and the filter are arranged on the fixing frame. The optical imaging device according to claim 1, further comprising an actuating element connected to the movable lens group, and the actuating element is used to drive the movable lens group to move relative to the fixed lens group. The optical imaging device according to claim 7, further comprising a second lens frame for carrying the movable lens group, and the actuating element is connected to the second lens frame. The optical imaging device according to claim 1, further comprising a first lens frame for carrying the fixed lens group. The optical imaging device according to claim 7, wherein the actuating element is a voice coil motor, a memory metal motor, a piezoelectric motor, or a combination of two or more thereof. The optical imaging device according to claim 1, further comprising an optical path changing element located in the imaging direction of the optical lenses, and the optical path changing element is used to change the light rays traveling parallel to an actual imaging direction to parallel to Travel in this acquisition direction. The optical imaging device according to claim 11, wherein the optical path changing element is a reflective sheet, and an included angle is formed between the reflective sheet and the imaging direction. The optical imaging device according to claim 11, wherein the light path changing element is a beam, the beam has a light incident surface and a light exit surface, the light entrance surface faces the actual image capturing direction, and the light exit surface faces The optical lenses have an included angle between the light incident surface and the light exit surface. The optical imaging device according to claim 1, wherein the optical imaging device has more than two sets of the fixed lens group, and the effective focal length of each fixed lens group is different. The optical imaging device according to claim 1, wherein the optical imaging device has two or more sets of the movable lens group, and the effective focal length of each movable lens group is different.

Images