JP2024004464A - lens assembly - Google Patents

Abstract

To provide a lens assembly.SOLUTION: A lens assembly includes a first lens, a second lens, a third lens, and a cover glass. The first lens has a positive refractive power and has a convex surface facing an image side. The second lens is a meniscus lens having a refractive power. The third lens has a positive refractive power and has a convex surface facing the image side. The first lens, the second lens, the third lens, and the cover glass are arranged along a first optical axis from the image side to an object side.SELECTED DRAWING: Figure 1

Description

TECHNICAL FIELD The present invention relates to a lens assembly, and particularly to a lens assembly applied to an electronic viewfinder.

The field of view of today's electronic viewfinders is mostly less than 30 degrees, which no longer meets modern requirements. The present invention proposes a lens assembly with a new structure that can enlarge the field of view, increase resolution, and effectively correct aberrations and chromatic aberrations. When applied to an electronic viewfinder, the field of view of the electronic viewfinder can be expanded to about 45 degrees.

The present invention aims to solve the above-mentioned problems by providing a lens assembly that enlarges the field of view, increases resolution, and also has good optical performance.

A lens assembly according to an exemplary embodiment of the invention has a first lens, a second lens, a third lens, and a cover glass. The first lens has a positive refractive power and a convex surface facing the image side. The second lens is a meniscus lens with refractive power. The third lens has positive refractive power and a convex surface facing the image side. The first lens, second lens, third lens, and cover glass are arranged in order from the image side to the object side along the first optical axis. The lens assembly satisfies at least one of the following conditions: 0.6<f/TTL<0.8; 0.85<(f+BFL)/TTL<1.2; 0.36<(f-BFL)/TTL<0.55; 1.6<(TTL+ BFL)/f<1.95; 0.5<(TTL-BFL)/f<1.15; where f is the effective focal length of the lens assembly and TTL is the first The distance from the image side of the lens to the light emitting surface, BFL, is the distance from the object side of the lens closest to the object side to the image side of the cover glass along the first optical axis.

In another exemplary embodiment, the lens assembly further includes a fourth lens having negative refractive power and having a concave surface facing the object side.

In yet another exemplary embodiment, the first lens is a biconvex lens and further has another convex surface facing the object side. The second lens has a negative refractive power, a concave surface facing the image side, and a convex surface facing the object side. The third lens is a biconvex lens, and further has another convex surface facing the object side. The fourth lens is installed between the third lens and the cover glass, is a biconcave lens, and further has another concave surface facing the image side.

In another exemplary embodiment, the first lens is a biconvex lens and further has another convex surface facing the object side. The second lens further has a convex surface facing the image side and a concave surface facing the object side. The third lens is a meniscus lens and further has a concave surface facing the object side. The fourth lens is installed between the third lens and the cover glass, is a meniscus lens, and further has a convex surface facing the image side.

In yet another exemplary embodiment, a fourth lens is placed between the third lens and the cover glass. The third lens and fourth lens are cemented. The first lens is not a cemented lens but a single lens. The second lens is not a cemented lens but a single lens. A spacing is provided between the first lens and the second lens.

In another exemplary embodiment, the fourth lens further has an image side facing toward the image side, the image side having no inflection point. The concave surface of the fourth lens does not have an inflection point.

In yet another exemplary embodiment, the lens assembly further includes a group of lenses, an image sensor element, and a display source. The fourth lens is installed between the third lens and the cover glass. The first lens and the second lens can be moved synchronously along the first optical axis to focus. The lens group is arranged along the second optical axis, and the first optical axis and the second optical axis are not coaxial. The image sensor elements are arranged along the second optical axis, and the first optical axis and the second optical axis are not coaxial. A display source is placed between the cover glass and the object side. The display source is coincide with the light emitting surface. The cover glass and the display source are arranged in order from the image side to the object side along the first optical axis.

In another exemplary embodiment, the lens assembly further includes a display source located between the cover glass and the object side. The fourth lens is installed between the second lens and the third lens. The first lens is a meniscus lens and further has a concave surface facing the object side. The second lens has a positive refractive power, a convex surface facing the image side, and a concave surface facing the object side. The fourth lens is a meniscus lens, and further has a convex surface facing the image side. The third lens is a biconvex lens, and further has another convex surface facing the object side. The first lens is not a cemented lens but a single lens. The second lens is not a cemented lens but a single lens. A spacing is provided between the first lens and the second lens. The convex surface of the third lens has no inflection point. The other convex surface of the third lens does not have an inflection point. The first lens and the second lens can be moved along the first optical axis to focus. The display source overlaps the light emitting surface. The cover glass and the display source are arranged in order from the image side to the object side along the first optical axis. The first lens, second lens, third lens, and fourth lens can be moved synchronously along the first optical axis to focus.

A detailed description is given in the following embodiments with reference to the accompanying drawings.

The lens assembly of the present invention expands the field of view, increases resolution, and also has good optical performance.

In order to make the above-mentioned objects, features, and advantages of the present invention more understandable, they will be described in further detail with reference to the following embodiments and accompanying drawings.
FIG. 3 is a lens layout diagram of the lens assembly according to the first embodiment of the present invention. According to a first embodiment of the invention, a longitudinal aberration diagram, a field curvature diagram, a distortion diagram, a lateral color diagram of a lens assembly, and FIG. 3 is a modulation transfer function diagram. FIG. 6 is a lens layout diagram of a lens assembly according to a second embodiment of the present invention. FIG. 7 is a longitudinal aberration diagram, a field curvature diagram, a distortion diagram, a lateral color diagram, and a modulation transition function diagram of a lens assembly according to a second embodiment of the present invention. FIG. 7 is a lens layout diagram of a lens assembly according to a third embodiment of the present invention. FIG. 7 is a longitudinal aberration diagram, a field curvature diagram, a distortion diagram, a lateral color diagram, and a modulation transition function diagram of a lens assembly according to a third embodiment of the present invention. FIG. 7 is a lens layout diagram of a lens assembly according to a fourth embodiment of the present invention.

The following description describes the best mode of carrying out the invention. This description is made for the purpose of illustrating the general principles of the invention and should not be considered in a limiting sense. The scope of the invention is best determined by reference to the claims appended hereto.

The present invention provides a lens assembly having a first lens, a second lens, a third lens, and a cover glass. The first lens has a positive refractive power and a convex surface facing the image side. The second lens is a meniscus lens with refractive power. The third lens has positive refractive power and a convex surface facing the image side. The first lens, second lens, third lens, and cover glass are arranged in order from the image side to the object side along the first optical axis. The lens assembly satisfies at least one of the following conditions: 0.6<f/TTL<0.8; 0.85<(f+BFL)/TTL<1.2; 0.36<(f-BFL)/TTL<0.55; 1.6<(TTL+ BFL)/f<1.95; 0.5<(TTL-BFL)/f<1.15; where f is the effective focal length of the lens assembly and TTL is the distance from the image side of the first lens along the first optical axis. , the distance between the light emitting surfaces, and BFL are the distances from the object side of the lens closest to the object side to the image side of the cover glass along the first optical axis.

Referring to Table 1, Table 2, Table 4, Table 5, Table 7, and Table 8, Table 1, Table 4, and Table 7 are according to the first, second, and third embodiments of the present invention, respectively. Optical specifications Table 2, Table 5, and Table 8 show the aspheric coefficients of each aspheric lens in Table 1, Table 4, and Table 7, respectively.

1, 3, and 5 are lens layout diagrams of lens assemblies according to first, second, and third embodiments of the present invention, respectively.

The first lenses L11, L21, and L31 are biconvex lenses having positive refractive power and are formed of a glass material, the image side surfaces S12, S22, and S32 are convex surfaces, and the object side surfaces S13, S23, and S33 are convex surfaces. , is a convex surface, and the image side surfaces S12, S22, S32 and the object side surfaces S13, S23, S33 are both aspherical surfaces.

The second lenses L12, L22, and L32 are meniscus lenses having negative refractive power, and are formed of a glass material. , is an aspherical surface.

The third lenses L13, L23, and L33 have positive refractive power and are made of a glass material, and the image side surfaces S16, S26, and S36 are convex surfaces.

The fourth lenses L14, L24, and L34 have negative refractive power and are made of a glass material, and the object side surfaces S18, S29, and S39 are concave surfaces.

In addition, lens assemblies 1, 2, and 3 satisfy at least one of the following conditions:

0.6<f/TTL<0.8;(1)

0.85<(f+BFL)/TTL<1.2;(2)

0.36<(f-BFL)/TTL<0.55;(3)

1.6<(TTL+BFL)/f<1.95;(4)

0.5<(TTL-BFL)/f<1.15;(5)

In the formula, TTL is the light emitting surface LS1, from the image side surface S12, S22, S32 of the first lens L11, L21, L31 along the first optical axis OA1, OA2, OA3 in the first to third embodiments. This is the interval between LS2 and LS3. f is the effective focal length of the lens assemblies 1, 2, and 3 in the first to third embodiments. In the first to third embodiments, BFL is from the object side S18, S29, S39 (closest to the object side) of the fourth lenses L14, L24, L34 along the first optical axes OA1, OA2, OA3, This is the interval between the image side surfaces S19, S210, and S310 of the cover glasses CG1, CG2, and CG3. With the lens assemblies 1, 2, and 3 satisfying at least one of the above conditions (1) to (5), the field of view is effectively increased, the resolution is effectively increased, and aberrations are effectively corrected. and chromatic aberrations are effectively corrected.

A detailed description of the lens assembly according to the first embodiment of the invention is as follows. Referring to FIG. 1, the lens assembly 1 includes an aperture ST1, a first lens L11, a second lens L12, a third lens L13, a fourth lens L14, and a display element DE1, all of which have a first optical axis OA1. are arranged in order from the image side to the object side. The first lens L11 and the second lens L12 can move synchronously and focus along the first optical axis OA1. When the first lens L11 and the second lens L12 move synchronously along the first optical axis OA1 and focus, the image of the third lens L13 is projected from the object side S15 of the second lens L12. The spacing of the side surfaces S16 ranges from 0.4 mm to 2 mm, and the effective focal length of the lens assembly 1 ranges from 12.359 mm to 12.173 mm. The display element DE1 has a cover glass CG1 and a display source DS1, both of which are arranged in order from the image side to the object side along the first optical axis OA1. The display source DS1 overlaps the light emitting surface LS1. In use, the human eye is positioned at the aperture ST1 and can see the image of the display source DS1.

According to the above, the image side surface S14 of the second lens L12 is a concave surface, and the object side surface S15 is a convex surface. The third lens L13 is a biconvex lens, the object side surface S17 is a convex surface, and the image side surface S16 and the object side surface S17 are both spherical surfaces. The fourth lens L14 is a biconcave lens, the image side surface S17 is a concave surface, and both the image side surface S17 and the object side surface S18 are spherical surfaces. The third lens L13 is fixed to the fourth lens L14 with cement. Both the image side surface S19 and the object side surface S110 of the cover glass CG1 are flat.

With the aforementioned lens, aperture ST1, and a design that satisfies at least one of conditions (1) to (5), the lens assembly 1 has an effectively enlarged field of view, an effectively increased resolution, and an effectively modified and effectively corrected chromatic aberrations.

Table 1 shows the optical specifications of the lens assembly 1 of FIG.

In Table 1, the concavity z of the aspheric surface of each aspheric lens is calculated by the following formula:
z=ch ² /{1+[1-(k+1)c ² h ² ] ^1/2 }+Ah ⁴ +Bh ⁶ +Ch ⁸ +Dh ¹⁰
where c is the curvature, h is the vertical distance from the lens surface to the optical axis, k is the conic constant, and A, B, C, and D are the aspheric coefficients.

In the first embodiment, the conical coefficient k and aspherical coefficients A, B, C, and D of each aspherical lens are shown in Table 2.

Table 3 shows parameters and condition values of conditions (1) to (5) according to the first embodiment of the present invention. As can be seen from Table 3, the lens assembly 1 of the first embodiment satisfies conditions (1) to (5).

In addition, the lens assembly 1 of the first embodiment can satisfy the optical performance requirements shown in FIG. From FIG. 2, the longitudinal aberration of the lens assembly 1 of the first embodiment is in the range of -0.14 mm to 0.04 mm, and the image plane of the lens assembly 1 of the first embodiment in the tangential direction and the sagittal direction. The curvature is in the range of -0.1 mm to 0.2 mm, the distortion of the lens assembly 1 of the first embodiment is in the range of -3% to 3%, and the lateral color of the lens assembly 1 of the first embodiment is in the range of -3% to 3%. is in the range of −1 μm to 10 μm, and the tangential and sagittal modulation transfer functions of the lens assembly 1 of the first embodiment are found to be in the range of 0.70 to 1.0. It can be seen that the longitudinal aberration, field curvature, distortion and lateral color of the lens assembly 1 of the first embodiment can be effectively corrected and the image resolution can meet the requirements. Therefore, the lens assembly 1 of the first embodiment can achieve good optical performance.

Referring to FIG. 3, the lens assembly 2 includes an aperture ST2, a first lens L21, a second lens L22, a third lens L23, a fourth lens L24, and a display element DE2, all of which have a first optical axis OA2. are arranged in order from the image side to the object side. The first lens L21 and the second lens L22 can move synchronously and focus along the first optical axis OA2. When the first lens L21 and the second lens L22 move synchronously along the first optical axis OA2 and focus, the image of the third lens L23 is projected from the object side S25 of the second lens L22. The spacing of the side surfaces S26 ranges from 0.06 mm to 1.636 mm, and the effective focal length of the lens assembly 2 ranges from 12.298 mm to 12.286 mm. The display element DE2 has a cover glass CG2 and a display source DS2, both of which are arranged in order from the image side to the object side along the first optical axis OA2. The display source DS2 overlaps the light emitting surface LS2. In use, the human eye is positioned at the aperture ST2 and can see the image of the display source DS2.

According to the above, the image side surface S24 of the second lens L22 is a concave surface, and the object side surface S25 is a convex surface. The third lens L23 is a biconvex lens, the object side surface S27 is a convex surface, and the image side surface S26 and the object side surface S27 are both spherical surfaces. The fourth lens L24 is a biconcave lens, the image side surface S28 is a concave surface, and the image side surface S28 and the object side surface S29 are both aspherical surfaces. Both the image side surface S210 and the object side surface S211 of the cover glass CG2 are flat.

With the aforementioned lens, aperture ST2, and a design that satisfies at least one of conditions (1) to (5), the lens assembly 2 can provide an effectively enlarged field of view, an effectively increased resolution, and an effectively modified and effectively corrected chromatic aberrations.

Table 4 shows the optical specifications of the lens assembly 2 of FIG.

In Table 4, the definition of the concavity z of the aspheric surface of each aspheric lens is the same as in Table 1, so it will not be described again here.

In the second embodiment, the conical coefficient k and aspherical coefficients A, B, C, and D of each aspherical lens are shown in Table 5.

Table 6 shows parameters and condition values of conditions (1) to (5) according to the second embodiment of the present invention. As can be seen from Table 6, the lens assembly 2 of the second embodiment satisfies conditions (1) to (5).

Besides, as seen in FIG. 4, the optical performance of the lens assembly 2 of the second embodiment can meet the requirements. As can be seen from FIG. 4, the longitudinal aberration of the lens assembly 2 of the second embodiment is in the range of -0.09 mm to 0.01 mm, and the longitudinal aberration of the lens assembly 2 of the second embodiment is in the tangential direction and the sagittal direction. The field curvature of the lens assembly 2 of the second embodiment is in the range of -0.1 mm to 0.4 mm, and the distortion of the lens assembly 2 of the second embodiment is in the range of -3% to 4%. The lateral color of is in the range 0 μm to 6 μm, and the tangential and sagittal modulation transfer functions of the lens assembly 2 of the second embodiment are in the range 0.75 to 1.0. It can be seen that the longitudinal aberration, field curvature, distortion and lateral color of the lens assembly 2 of the second embodiment are effectively corrected, and the image resolution can meet the requirements. Therefore, the lens assembly 2 of the second embodiment can achieve good optical performance.

Referring to FIG. 5, the lens assembly 3 includes an aperture ST3, a first lens L31, a second lens L32, a third lens L33, a fourth lens L34, and a display element DE3, all of which have a first optical axis OA3. are arranged in order from the image side to the object side. The first lens L31 and the second lens L32 can move synchronously and focus along the first optical axis OA3. When the first lens L31 and the second lens L32 move synchronously along the first optical axis OA3 and focus, the image of the third lens L33 is captured from the object side S35 of the second lens L32. The spacing of the side surfaces S36 ranges from 0.06 mm to 1.7 mm, and the effective focal length of the lens assembly 3 ranges from 12.198 mm to 12.677 mm. The display element DE3 has a cover glass CG3 and a display source DS3, both of which are arranged in order from the image side to the object side along the first optical axis OA3. Display source DS3 overlaps light emitting surface LS3. In use, the human eye is located at the aperture ST3 and can see the image of the display source DS3.

According to the above, the image side surface S34 of the second lens L32 is a convex surface, and the object side surface S35 is a concave surface. The third lens L33 is a meniscus lens, the object side surface S37 is a concave surface, and the image side surface S36 and the object side surface S37 are both aspherical surfaces. The fourth lens L34 is a meniscus lens, the image side surface S38 is a convex surface, and both the image side surface S38 and the object side surface S39 are aspherical surfaces. Both the image side surface S310 and the object side surface S311 of the cover glass CG3 are flat.

With the aforementioned lens, aperture ST3, and a design that satisfies at least one of conditions (1) to (5), the lens assembly 3 has an effectively enlarged field of view, an effectively increased resolution, and an effectively modified and effectively corrected chromatic aberrations.

Table 7 shows the optical specifications of the lens assembly 3 of FIG.

In Table 7, the definition of the degree of concavity z of the aspheric surface of each aspheric lens is the same as in Table 1, so it will not be described again here.

In the third embodiment, the conical coefficient k and aspherical coefficients A, B, C, and D of each aspherical lens are shown in Table 8.

Table 9 shows parameters and condition values of conditions (1) to (5) according to the third embodiment of the present invention. As can be seen from Table 9, the lens assembly 3 of the third embodiment satisfies conditions (1) to (5).

Besides, as shown in FIG. 6, the optical performance of the lens assembly 3 of the third embodiment can meet the requirements. As can be seen from FIG. 6, the longitudinal aberration of the lens assembly 3 of the third embodiment is in the range of -0.02 mm to 0.05 mm, and the longitudinal aberration of the lens assembly 3 of the third embodiment is in the tangential direction and the sagittal direction. The field curvature of the lens assembly 3 of the third embodiment is in the range of -0.2 mm to 0.5 mm, and the distortion of the lens assembly 3 of the third embodiment is in the range of -3% to 4%. The lateral color of is in the range -2 μm to 5 μm, and the tangential and sagittal modulation transfer functions of the lens assembly 3 of the third embodiment are in the range 0.56 to 1.0. It can be seen that the longitudinal aberration, field curvature, distortion and lateral color of the lens assembly 3 of the third embodiment are effectively corrected, and the image resolution can meet the requirements. Therefore, the lens assembly 3 of the third embodiment can achieve good optical performance.

Referring to FIG. 7, the lens assembly 4 includes an aperture ST4, a first lens L41, a second lens L42, a fourth lens L44, a third lens L43, an optical filter OF4, and a display element DE4. They are arranged in order from the image side to the object side along one optical axis OA4. The first lens L41, the second lens L42, the fourth lens L44, and the third lens L43 can move synchronously and focus along the first optical axis OA4. When the first lens L41, second lens L42, fourth lens L44, and third lens L43 move synchronously and focus along the first optical axis OA4, the object of the third lens L43 The distance from the side surface S49 to the image side surface S410 of the optical filter OF4 is in the range of 2.89 mm to 3.97 mm. The display element DE4 has a cover glass CG4 and a display source DS4, both of which are arranged in order from the image side to the object side along the first optical axis OA4. Display source DS4 overlaps light emitting surface LS4. In use, the human eye is positioned at the aperture ST4 and can see the image of the display source DS4.

The first lens L41 is a meniscus lens having positive refractive power and is formed of a glass material, the image side surface S42 is a convex surface, the object side surface S43 is a concave surface, and the image side surface S42 and , object side surface S43 are both aspherical surfaces.

The second lens L42 is a meniscus lens having positive refractive power and is formed of a glass material, the image side surface S44 is a convex surface, the object side surface S45 is a concave surface, and the image side surface S44 and the object side surface are convex. Both side surfaces S45 are aspherical.

The fourth lens L44 is a meniscus lens having negative refractive power and is formed of a glass material, the image side surface S46 is a convex surface, the object side surface S47 is a concave surface, and the image side surface S46 and , object side surface S47 are both aspherical surfaces.

The third lens L43 is a biconvex lens having positive refractive power and is formed of a glass material, the image side surface S48 is a convex surface, the object side surface S49 is a convex surface, and the image side surface S48 and the object side surface are convex. Both side surfaces S49 are aspherical.

Both the image side surface S410 and the object side surface S411 of the optical filter OF4 are flat.

Both the image side surface S412 and the object side surface S413 of the cover glass CG4 are flat.

With the aforementioned lens, aperture ST4, and a design that satisfies at least one of conditions (1) to (5), the lens assembly 4 can provide an effectively enlarged field of view, an effectively increased resolution, and an effectively modified and effectively corrected chromatic aberrations.

Table 10 shows the optical specifications of lens assembly 4 of FIG.

In Table 10, the concavity z of the aspherical surface of each aspherical lens is calculated by the following formula:
z=ch ² /{1+[1-(k+1)c ² h ² ] ^1/2 }+Ah ⁴ +Bh ⁶ +Ch ⁸ +Dh ¹⁰ +Eh ¹² +Fh ¹⁴
where c is the curvature, h is the vertical distance from the lens surface to the optical axis, k is the conic coefficient, and A, B, C, D, E, and F are the aspheric coefficients.

In the fourth embodiment, the conical coefficient k and aspherical coefficients A, B, C, D, E, and F of each aspherical lens are shown in Table 11.

Table 12 shows parameters and condition values of conditions (1) to (5) according to the fourth embodiment of the present invention. As can be seen from Table 12, the lens assembly 4 of the fourth embodiment satisfies conditions (1) to (5).

In the embodiments described above, the lens assembly has four lenses, but it can be appreciated that further lens groups may be added and the lens groups may be arranged along the second optical axis and arranged along the first optical axis. It is also within the scope of the present invention that the optical axis and the second optical axis are not coaxial.

In the above embodiments, the lens assembly may include an additional image sensor element, and the image sensor element is arranged along a second optical axis, and the first optical axis and the second optical axis are not coaxial. It is also within the scope of the present invention that there is no such thing.

Although preferred embodiments of the present invention have been disclosed as described above, these are by no means limited to the present invention, and anyone skilled in the art will be able to make various modifications without departing from the spirit of the present invention. can be added.

1, 2, 3...Lens assembly ST1, ST2, ST3...Aperture L11, L21, L31...First lens L12, L22, L32...Second lens L13, L23, L33...Third lens L14, L24, L34...Fourth Lenses DE1, DE2, DE3...Display elements CG1, CG2, CG3...Cover glasses DS1, DS2, DS3...Display sources LS1, LS2, LS3...Light emitting surfaces OA1, OA2, OA3...Optical axes S11, S21, S31...Aperture surface S12 , S22, S32...first lens image side surface S13, S23, S33...first lens object side surface S14, S24, S34...second lens image side surface S15, S25, S35...second lens object side surface S16, S26, S36...th Three lens image side surfaces S17, S27, S37... Third lens object side surface S17, S28, S38... Fourth lens image side surface S18, S29, S39... Fourth lens object side surface S19, S210, S310... Image side surface S110 of cover glass, S211, S311...object side of cover glass

Claims (8)

A lens assembly,
a first lens having positive refractive power and having a convex surface facing the image side;
a second lens having refractive power and being a meniscus lens;
a third lens having positive refractive power and having a convex surface facing the image side, and
has a cover glass,
The first lens, the second lens, the third lens, and the cover glass are arranged in order from the image side to the object side along the first optical axis, and the lens assembly is arranged under the following conditions. Satisfies at least one of:
0.6<f/TTL<0.8;
0.85<(f+BFL)/TTL<1.2;
0.36<(f-BFL)/TTL<0.55;
1.6<(TTL+BFL)/f<1.95;
0.5<(TTL-BFL)/f<1.15;
In the formula, f is the effective focal length of the lens assembly, TTL is the distance from the image side of the first lens to the light emitting surface along the first optical axis, and BFL is the distance between the first lens and the light emitting surface. A lens assembly characterized in that the distance is from the object side of the lens closest to the object side to the image side of the cover glass along the optical axis. The lens assembly according to claim 1, further comprising a fourth lens, the fourth lens having a negative refractive power and a concave surface facing the object side. The first lens is a biconvex lens, and further has another convex surface facing the object side,
The second lens has negative refractive power and has a concave surface facing the image side and a convex surface facing the object side,
The third lens is a biconvex lens, and further has another convex surface facing the object side, and
2. The fourth lens is disposed between the third lens and the cover glass, is a biconcave lens, and further has another concave surface facing the image side. Lens assembly as described in . The first lens is a biconvex lens, and further has another convex surface facing the object side,
The second lens further has a convex surface facing the image side and a concave surface facing the object side,
The third lens is a meniscus lens, and further has a concave surface facing the object side,
3. The fourth lens is installed between the third lens and the cover glass, is a meniscus lens, and further has a convex surface facing the image side. lens assembly. the fourth lens is installed between the third lens and the cover glass,
the third lens and the fourth lens are fixed with cement;
The first lens is not a cemented lens but a single lens,
The second lens is not a cemented lens but a single lens, and
3. The lens assembly of claim 2, wherein a gap is provided between the first lens and the second lens. further comprising a display source installed between the cover glass and the object side;
the fourth lens is installed between the second lens and the third lens,
The first lens is a meniscus lens, and further has a concave surface facing the object side,
The second lens has a positive refractive power, a convex surface facing the image side, and a concave surface facing the object side,
The fourth lens is a meniscus lens, and further has a convex surface facing the image side,
The third lens is a biconvex lens, and further has another convex surface facing the object side,
The first lens is not a cemented lens but a single lens,
The second lens is not a cemented lens but a single lens,
a gap is provided between the first lens and the second lens;
the convex surface of the third lens does not have an inflection point;
Another convex surface of the third lens does not have an inflection point,
The first lens and the second lens can move along the first optical axis to focus,
the display source overlaps the light emitting surface;
The cover glass and the display source are arranged in order from the image side to the object side along the first optical axis,
The first lens, the second lens, the third lens, and the fourth lens can move synchronously along the first optical axis to focus. The lens assembly according to item 2. The fourth lens further has an image side surface facing the image side, the image side surface does not have an inflection point, and
Lens assembly according to any one of claims 2 to 6, characterized in that the concave surface of the fourth lens has no inflection point. Furthermore, it has a lens group, an image sensor element, and a display source,
the fourth lens is installed between the third lens and the cover glass,
The first lens and the second lens can move synchronously and focus along the first optical axis,
The lens group is arranged along a second optical axis, and the first optical axis and the second optical axis are not coaxial,
the image sensor elements are arranged along the second optical axis, and the first optical axis and the second optical axis are not coaxial;
The display source is installed between the cover glass and the object side,
the display source overlaps the light emitting surface;
7. The cover glass and the display source are arranged in order from the image side to the object side along the first optical axis. Lens assembly as described in .