CN111796386A

CN111796386A - Optical imaging device

Info

Publication number: CN111796386A
Application number: CN202010598008.8A
Authority: CN
Inventors: 黄海若; 庄江源; 曾正德; 简上杰
Original assignee: Lijing Innovation Co ltd
Current assignee: Lijing Innovation Co ltd
Priority date: 2019-08-14
Filing date: 2020-06-28
Publication date: 2020-10-20
Also published as: CN111988507B; TWI769465B; TW202045976A; CN111988507A

Abstract

An optical imaging device comprises a plurality of optical lenses. The plurality of optical lenses are arranged along an optical axis, are used for imaging towards an imaging direction and are imaged on an imaging surface. The plurality of optical lens sections are divided into at least one fixed lens group and at least one movable lens group; the fixed lens group is fixedly arranged, and the movable lens group is used for moving relative to the fixed lens group so as to zoom the optical lens.

Description

Optical imaging device

Technical Field

The present invention relates to an arrangement of an optical lens group, and more particularly to an optical imaging apparatus.

Background

As shown in fig. 1 and 2, the optical lens assembly of the photographing apparatus is formed by sequentially arranging a plurality of optical lenses along an optical axis L to obtain a longer Effective Focal Length (EFL) in a limited space for imaging on an imaging plane I. The imaging plane I is an imaginary plane for disposing the image sensor 140'. The plurality of optical lenses of the optical lens group are usually fixed on a lens frame to form a single optical lens group 120'.

As shown in fig. 1 and 2, when the object distance is changed, the optical lens assembly 120' needs to be moved back and forth to change the back focal length (back focal length) for focusing the object, so that the objects with different object distances can be clearly imaged on the imaging plane I. Alternatively, when the photographing device is unstable, the optical lens group 120' is moved up, down, left, and right to perform optical anti-shake (OIS). The optical lens assembly 120 'composed of a plurality of optical lens groups is heavy, and requires a Voice Coil Motor (VCM) or other actuator 130' with a large size to drive the displacement. Portable electronic devices such as smart phones or tablet computers are generally thin and have limited internal space. The large size of the actuator 130 'occupies space, which is not favorable for disposing the optical lens assembly 120' in a portable electronic device with limited space. Meanwhile, the actuator 130' with large driving force consumes larger driving current, and consumes more power.

Disclosure of Invention

In view of the above problems, the present invention provides an optical imaging apparatus that reduces the magnitude 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 plurality of optical lenses are arranged along an optical axis, are used for imaging towards an imaging direction and are imaged 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 set is fixed, and the movable lens set is used for moving relative to the fixed lens set.

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

In at least one embodiment, the movable lens set is configured to be displaced relative to the fixed lens set on a plane perpendicular to the optical axis.

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

In at least one embodiment, the optical imaging device further includes a filter disposed 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 disposed on the fixing frame.

In at least one embodiment, the optical imaging apparatus further includes an actuating element coupled to the movable lens set, wherein the actuating element is used for driving the movable lens set to move relative to the fixed lens set.

In at least one embodiment, the optical imaging device further includes a second lens frame for carrying the movable lens set, 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 the fixed lens set.

In at least one embodiment, the actuator 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 image capturing direction of the optical lenses, and the optical path changing element is configured to change the light traveling parallel to an actual image capturing direction into light traveling parallel to the image capturing direction.

In at least one embodiment, the optical path changing element is a reflector, and an included angle is formed between the reflector and the image capturing direction.

In at least one embodiment, the light path changing element is a prism, the prism has a light incident surface and a light emitting surface, the light incident surface faces the actual image capturing direction, the light emitting surface faces the optical lenses, and an included angle is formed between the light incident surface and the light emitting surface.

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

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

The invention divides a plurality of optical lenses into a plurality of groups. When adjusting optical characteristics, such as focusing, zooming, and optical hand shock prevention, only the movable lens group of the plurality of optical lenses is moved. The weight of the movable lens group or the displacement stroke required for adjusting the optical characteristics is less than the weight of the whole optical lens group or the required displacement stroke. Therefore, the driving force required for moving the actuating element of the movable lens group is smaller than the driving force required for moving the whole optical lens group, so that the size of the actuating element can be effectively reduced, and the whole size and weight of the optical imaging device can be further reduced. Meanwhile, because the driving force required to be provided by the actuating element is reduced, the driving current required by the actuating element can be reduced, and the power consumption condition of the optical imaging device is improved.

The invention is described in detail below with reference to the drawings and specific examples, but the invention is not limited thereto.

Drawings

Fig. 1 is a schematic top view of a conventional imaging device.

FIG. 2 is a schematic diagram illustrating an optical lens set moving for focusing in the prior art.

Fig. 3 is a schematic top view of an optical imaging apparatus according to a first embodiment of the present invention.

Fig. 4 is a schematic cross-sectional view of an optical imaging apparatus according to a first embodiment of the present invention.

FIG. 5 is a schematic diagram of an optical imaging apparatus for focusing according to a first embodiment of the present invention.

Fig. 6 is a schematic cross-sectional view of an optical imaging apparatus according to a second embodiment of the present invention.

FIG. 7 is a cross-sectional view of another optical imaging apparatus according to a second embodiment of the present invention.

Fig. 8 and 9 are schematic diagrams illustrating an arrangement of a fixed lens set and a movable lens set according to the first and second embodiments of the invention.

FIG. 10 is a diagram illustrating an arrangement of a fixed lens group and a movable lens group according to a third embodiment of the invention.

FIG. 11 is a diagram illustrating an arrangement of a fixed lens group and a movable lens group according to a fourth embodiment of the invention.

Fig. 12 and 13 are schematic diagrams illustrating an arrangement of a fixed lens group and a movable lens group according to a fifth embodiment of the invention.

Wherein, the reference numbers:

100 optical imaging device

110 fixed lens group

112 first lens frame

120 movable lens group

120' optical lens group

122 second lens frame

130, 130' actuating element

140, 140' image sensor

150 light filter

160 fixing frame

170 optical path changing element

172 incident light surface

174 light-emitting surface

180: base

300 casing

310 window

C imaging direction

C' actual image capturing direction

I image plane

L is the optical axis

P1 first position

P2 second position

Δ P initial displacement stroke

Detailed Description

The invention will be described in detail with reference to the following drawings, which are provided for illustration purposes and the like:

referring to fig. 3 and fig. 4, an optical imaging device 100 for imaging towards an imaging direction C and imaging on an imaging plane I according to a first embodiment of the disclosure is shown; the image plane I is an imaginary plane.

Referring to fig. 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 for being disposed in an electronic device; the electronic device may be, but is not limited to, a smart phone, a tablet computer, a notebook computer, a monitor, or a standalone camera.

As shown in fig. 3 and 4, the optical lenses are disposed along an optical axis L to capture an image in an image capturing direction C and form an image on an image plane I. The plurality of optical lenses are divided into one or more fixed lens groups 110 and one or more movable lens groups 120; the first embodiment is described by taking a set of fixed lens groups 110 and a set of movable lens groups 120 as an example, but the number of the fixed lens groups 110 and the movable lens groups 120 may be arbitrarily changed.

As shown in fig. 3 and 4, the fixed lens group 110 is fixed, and the movable lens group 120 is configured to move 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 image plane I, and the back focal length from the optical lenses to the image plane I can be changed to focus on objects with different object distances and clearly image on the image plane I; however, the present invention does not exclude the positions of the fixed lens group 110 and the movable lens group 120 from being interchanged; that is, the arrangement order of the fixed lens group 110 and the movable lens group 120 on the optical axis L is not limited and can be changed arbitrarily.

As shown in fig. 3 and 4, the movable lens group 120 is movable back and forth on the optical axis L or up and down and left and right on a plane perpendicular to the optical axis L with respect to the fixed lens group 110. The direction in which the movable lens group 120 is displaced with respect to the fixed lens group 110 depends on the function to be performed. When the focusing function is performed, the movable lens assembly 120 is moved back and forth on the optical axis L relative to the fixed lens assembly 110. When the optical anti-shake function is performed, the movable lens assembly 120 is vertically displaced relative to the fixed lens assembly 110 in a direction perpendicular to the optical axis L. Of course, the two aforementioned functions may be performed simultaneously, so that the movable lens group 120 performs three-axis movement.

As shown in fig. 3, the image sensor 140 and the filter 150 form an image sensing module. The image sensor 140 is located on the image plane I, so that the images of the optical lenses can fall on the image sensor 140. The image sensor 140 performs image capturing and encodes to generate an image signal. The filter 150 is disposed between the optical lenses and the image sensor 140, and is used for adjusting the wavelength distribution of light entering the image sensor 140.

As shown in fig. 3 and 4, the actuating element 130 is directly or indirectly connected to the movable lens set 120, so that the movable lens set 120 and the actuating element 130 form an adjustment module. The actuating element 130 is used to drive the movable lens set 120 to move relative to the fixed lens set 110 for performing a focusing function or an optical anti-shake function. The actuator 130 may be, but is not limited to, a Voice Coil Motor (VCM), a Memory metal Motor (SMA), a piezoelectric Motor (Piezo), or a combination of two or more thereof. The actuator 130 may be a Voice Coil Motor (VCM), a Memory metal Motor (SMA), a piezoelectric Motor (Piezo), or a combination of two or more thereof. Meanwhile, for example, the voice coil motor is provided, and the number of coils in the voice coil motor can be configured as required, so that the movable lens group 120 can perform single-axis movement on the optical axis L for focusing, and perform two-axis linear movement perpendicular to the optical axis L for optical hand-shake prevention, or perform three-axis linear movement simultaneously for focusing and optical hand-shake prevention. In addition to linear movement in three axes, the movable lens group 120 may be tilted or rotated appropriately to correct the optical axis L by the arrangement of the movable lens group 120 with a difference in drive stroke between the opposite sides.

As shown in fig. 4, the fixed lens assembly 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 assembly 110, the adjusting module and the image sensor module can be sequentially assembled and connected. The base 180 may be a separate substrate, such as a printed circuit board, so that the optical imaging device 100 forms a single module for being mounted on an electronic device. The base 180 may also be part of the housing 300 of the electronic device.

Referring to FIG. 4, the optical imaging device 100 further includes 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 set 110, and the image sensor 140 and the optical filter 150 are fixed on the fixing frame 160, so that the fixed lens set 110, the optical filter 150 and the image sensor 140 are indirectly fixed on the base 180. The second lens frame 122 carries the movable lens set 120, and the actuator 130 is connected to the second lens frame 122 and fixed to the base 180, such that the movable lens set 120 is indirectly connected to the actuator 130. The fixing structure is only exemplary, and the invention is not limited to the fixing structure for disposing the optical lenses, the actuating element 130 and the image sensor 140. In some embodiments, the optical imaging apparatus 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 disposed in one lens barrel, the movable lens group 120 and the actuating element 130 are disposed in another lens barrel, and the two lens barrels are connected to each other.

As shown in fig. 4 and 5, the number of optical lenses of the fixed lens group 110 and the movable lens group 120 is generally as small as possible, so that the movable lens group 120 can have a smaller weight, and a smaller driving force can drive the movable lens group 120 to move, so that the size of the actuator 130 can be effectively reduced. Generally, the sizes of the optical lenses in the optical lens group with long focal length are sequentially reduced, so that the optical lens at the imaging end has a smaller weight; at this time, the optical lens close to the image plane I may be selected as the movable lens group 120, such that the movable lens group 120 is located between the fixed lens group 110 and the image plane I, and the weight of the movable lens group 120 is smaller than that of the fixed lens group 110, and the selection of the movable lens group 120 is only one solution, and is not used to limit the selection of the movable lens group 120 in the present invention.

As shown in fig. 5, when the optical lens group is focused, for example, the shooting distance is changed from Infinity (Infinity) to a close distance, the back focal length from the optical lens group to the imaging plane I needs to be changed to complete focusing and make the imaged image clear. In the optical imaging apparatus 100 according to one or more embodiments of the present invention, the back focal length can be changed for focusing by moving the movable lens group 120 without moving the entire optical lens group. Since the number of optical lenses and the occupied space of the movable lens group 120 are smaller than that of the entire optical lens group, the actuator 130 can be reduced in weight or size, and the driving current required for the actuator 130 can be reduced.

The prior art is illustrated in fig. 2 and compared with fig. 5, which is an example of the present invention. The Effective Focal Length (EFL) of the movable lens group 120 is substantially smaller than that of the entire optical lens group. When the same focusing effect is achieved, the displacement stroke (the amount of change in the back focal length) required for moving the movable lens group 120 from the first position P1 to the second position P2 is less than the initial displacement stroke Δ P required for moving the entire optical lens group for focusing.

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

Referring to fig. 2 and 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, the initial displacement Δ P required to move the entire optical lens group for focusing is 0.619 mm. If the effective focal length of the optical lens group is still 26.6mm, but it is divided into the fixed lens group 110 with an effective focal length of 13.311mm and the movable lens group 120 with an effective focal length of-8.213 mm as shown in fig. 5, the movable lens group 120 only needs to be moved during focusing, and the displacement distance 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.

Referring to fig. 6 and fig. 7, an optical imaging device 100 according to a second embodiment of the disclosure is shown. 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 located in the image capturing direction C of the optical lenses for changing the light rays traveling parallel to an actual image capturing direction C' to travel parallel to the image capturing direction C. That is, the optical imaging device 100 may be configured as a periscope structure, so that the optical axes L of the optical lenses do not need to be configured along the thickness direction of the electronic device, which is beneficial for application in a light and thin electronic device.

As shown in fig. 6, in one embodiment, the optical path changing element 170 is a reflective sheet, and the reflective sheet forms an angle with the image capturing direction C. The angle between the image capturing 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 passing through the window 310 of the electronic device housing 300 can pass through the reflective sheet, change the traveling direction, pass through the fixed lens group 110 and the movable lens group 120, and form an image on the image sensor 140.

In one embodiment, as shown in FIG. 7, the optical path altering component 170 is a prism. The prism has a light incident surface 172 and a light emitting surface 174. The light incident surface 172 faces the actual image capturing direction C ', the light emitting surface 174 faces the optical lenses, and an included angle is formed between the light incident surface 172 and the light emitting surface 174 to change the light traveling along the actual image capturing direction C' to the image capturing direction C.

Referring to fig. 8 and 9, in the first and second embodiments, the relative positions of the fixed lens group 110 and the movable lens group 120 may be varied. The optical path changing element 170 shown in the figure may be omitted when the image capturing direction C and the actual image capturing direction C' are the same.

As shown in fig. 8, the movable lens group 120 may be located between the fixed lens group 110 and the image plane I, that is, the movable lens group 120 is located between the fixed lens group 110 and the image sensor 140. Therefore, the optical lens group close to the image sensor 140 is moved to change the back focal length during focusing.

As shown in fig. 9, the fixed lens group 110 may be located between the movable lens group 120 and the image plane I, that is, the fixed lens group 110 is located between the movable lens group 120 and the image sensor 140. Therefore, the front focal length is changed by moving the optical lens group away from the image sensor 140 during focusing.

Fig. 10 shows an optical imaging device 100 according to a third embodiment of the present invention. The optical imaging device 100 includes two fixed lens sets 110 and a movable lens set 120. The optical path changing element 170 shown in the figure may be omitted when the image capturing direction C and the actual image capturing 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 at the middle of the plurality of optical lenses moves, so that the movable lens group 120 can zoom. The two fixed lens groups 110 do not need to have the same optical lens composition, nor the same effective focal length.

Fig. 11 shows an optical imaging device 100 according to a fourth embodiment of the present invention. The optical imaging device 100 includes a fixed lens set 110 and a movable lens set 120. The optical path changing element 170 shown in the figure may be omitted when the image capturing direction C and the actual image capturing direction C' are the same. The fixed lens group 110 is located between the two movable lens groups 120. When focusing is performed, the optical lens group located at the front section and the rear section of the plurality of optical lenses is moved, and the front focal length and the rear focal length are changed. The 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.

Fig. 12 and 13 show an optical imaging device 100 according to a fifth embodiment of the present invention. The optical imaging device 100 includes a plurality of fixed lens sets 110 and a plurality of movable lens sets 120. The optical path changing element 170 shown in the figure may be omitted when the image capturing direction C and the actual image capturing direction C' are the same. The arrangement of the fixed lens group 110 and the movable lens group 120 is shown for illustrative purposes only, and other arrangements are possible. When focusing is performed, only the movable lens group 120 needs to be moved, and all the optical lenses do not need to be moved at the same time. In addition, in the plurality of movable lens sets 120, only the movable lens set 120 located between the two fixed lens sets 110 may be moved according to the actual image capturing requirement, so as to achieve the zooming effect, and it is not necessary that the plurality of movable lens sets 120 move simultaneously for focusing or zooming. The plurality of movable lens groups 120 do not need to have the same optical lens composition, nor 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, may be changed arbitrarily, and is not limited to the number and the arrangement order shown in fig. 8 to 13. In particular, different optical adjustment effects can be achieved by moving the movable lens group 120 at different positions; for example, changing the front focal length (front focal length) or the rear focal length can focus on objects with different object distances, and changing the relative position of the movable lens group 120 between the two fixed lens groups 110 can zoom.

The invention divides a plurality of optical lenses into a plurality of groups. When the optical characteristics are adjusted, only the movable lens group 120 among the plurality of optical lenses is moved. The weight of the movable lens group 120 or the required displacement stroke for adjusting the optical characteristics is less than the weight of the entire optical lens group or the required displacement stroke. Therefore, the driving force required for moving the actuating element 130 of the movable lens group 120 is smaller than the driving force required for moving the entire optical lens group, so that the size of the actuating element 130 can be effectively reduced, and the overall size and weight of the optical imaging apparatus 100 can be reduced. Meanwhile, the driving force required to be provided by the actuator 130 is reduced, so that the driving current required by the actuator 130 can also be reduced, and the power consumption of the optical imaging apparatus 100 is improved.

The present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof, and it should be understood that various changes and modifications can be effected therein by one skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.

Claims

1. An optical imaging apparatus, comprising:

a plurality of optical lenses, which are arranged along an optical axis, are used for imaging towards an imaging direction and are imaged 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 set is fixed, and the at least one movable lens set is used for moving relative to the at least one fixed lens set.

2. The optical imaging apparatus as claimed in claim 1, wherein the at least one movable lens set is configured to be displaced back and forth on the optical axis relative to the at least one fixed lens set.

3. The optical imaging apparatus of claim 1, wherein the at least one movable lens set is configured to be displaced relative to the at least one fixed lens set in a plane perpendicular to the optical axis.

4. The optical imaging device according to claim 1, further comprising an image sensor located on the imaging surface.

5. The optical imaging device according to claim 4, further comprising a filter disposed between the optical lenses and the image sensor.

6. The optical imaging apparatus of claim 5, further comprising a holder, wherein the image sensor and the filter are disposed on the holder.

7. The optical imaging apparatus as claimed in claim 1, further comprising an actuator coupled to the movable lens set for driving the movable lens set to move relative to the fixed lens set.

8. The optical imaging device as claimed in claim 7, further comprising a second lens frame for carrying the movable lens set, wherein the actuator is connected to the second lens frame.

9. The optical imaging device as claimed in claim 1, further comprising a first lens frame for carrying the fixed lens group.

10. The optical imaging apparatus of claim 7, wherein the actuator is a voice coil motor, a memory metal motor, a piezoelectric motor, or a combination of two or more thereof.

11. The optical imaging apparatus as claimed in claim 1, further comprising a light path changing element disposed in the image capturing direction of the optical lenses for changing light traveling parallel to an actual image capturing direction to travel parallel to the image capturing direction.

12. The optical imaging apparatus as claimed in claim 11, wherein the optical path changing element is a reflector plate, and an included angle is formed between the reflector plate and the image capturing direction.

13. The optical imaging apparatus as claimed in claim 11, wherein the optical path changing element is a prism having an incident surface and an exit surface, the incident surface faces the actual image capturing direction, the exit surface faces the optical lenses, and an included angle is formed between the incident surface and the exit surface.

14. The optical imaging device of claim 1, wherein the optical imaging device has more than two fixed lens groups, and the effective focal lengths of the fixed lens groups are different.

15. The optical imaging device of claim 1, wherein the optical imaging device has more than two movable lens sets, and the effective focal lengths of the movable lens sets are different.