A lens group, optical module and optical device

Abstract

Embodiments of the present application provide a lens group, an optical module and an optical device. The lens group comprises a first lens and a second lens along an optical axis in sequence, and the first lens and the second lens are both prisms, wherein the first lens satisfies: the second lens satisfies: wherein the first lens and the second lens are glued together, so that the lens group can focus light and realize off-axis transmission of light at the same time.

Description

Technical Field

[0001] This application relates to the field of optical lens technology, and more specifically, to a lens assembly, an optical module, and an optical device. Background Technology

[0002] With the continuous development of optical technology and the increasing diversification of application demands, traditional lens groups have gradually revealed some limitations in terms of function and performance. For example, in some application scenarios that require simultaneous light focusing and off-axis transmission, traditional lens groups often fail to meet the requirements. On the one hand, the structural design of traditional lens groups is relatively fixed, and the control over the direction of light deflection is not flexible enough, making it difficult to achieve precise off-axis transmission; on the other hand, their optical performance is somewhat insufficient when facing complex optical requirements, such as high-precision light focusing and light deflection in specific directions.

[0003] While some existing technologies can achieve off-axis light transmission, these designs are typically quite complex. This not only increases the manufacturing difficulty and cost of the lens group but may also lead to a larger optical system size, hindering the miniaturization and integration of optical devices. Furthermore, some designs, while achieving off-axis light transmission, negatively impact the focusing effect, failing to balance both focusing and off-axis transmission performance.

[0004] In view of this, a new technical solution is needed to solve the above-mentioned technical problems. Summary of the Invention

[0005] The purpose of this application is to provide a new technology solution for lens groups, optical modules, and optical devices.

[0006] According to a first aspect of the embodiments of this application, a lens group is provided. The lens group includes a first lens and a second lens sequentially along the optical axis, wherein both the first lens and the second lens are prisms, and the first lens satisfies the following:

[0007]

[0008] Where d1 is the thickness of the first lens at coordinates (x, y, z), D0 is the reference thickness of the first lens, A is a constant, n1 is the refractive index of the first lens at coordinates (x, y, z), n0 is the reference refractive index of the first lens, and B is a constant; the second lens satisfies:

[0009]

[0010] Where d2 is the thickness of the second lens at coordinates (x, y, z), D0 is the reference thickness of the second lens, A is a constant, n2 is the refractive index of the second lens at coordinates (x, y, z), n0 is the reference refractive index of the second lens, and B is a constant.

[0011] The first lens and the second lens are cemented together, so that the lens group can focus light while enabling off-axis light transmission.

[0012] Optionally, the lens group deflects the light rays in the direction of y, the deflection amount of the lens group is δ, and the optical path difference phase function of the lens group is:

[0013] .

[0014] Optionally, the focal length of the lens group is f = 1 / (4×A×B×δ); the off-axis amount y of the lens group off =λ / 2π×(2×n0×A-(8×D0×B×δ) / 3)×L, where L is the axial length of the lens group.

[0015] Optionally, the offset δ of the lens group ranges from 0.1 mm to 2 mm.

[0016] Optionally, the cemented surfaces of the first lens and the second lens are both vertical planes, and the lens group is provided with an incident light surface and an exit light surface, wherein the incident light surface is a first inclined plane, the exit light surface is a second inclined plane, and the first inclined plane and the second inclined plane are asymmetrically arranged.

[0017] Optionally, an optical adhesive is provided between the cemented surfaces of the first lens and the second lens, wherein the refractive index of the optical adhesive is between the refractive index of the first lens and the refractive index of the second lens.

[0018] Optionally, the constants A and B satisfy the relationship 1 ≤ A / B ≤ 5.

[0019] Optionally, the lens group focuses light on a spot diameter of less than 5 μm within the operating wavelength range.

[0020] According to a second aspect of the present application, an optical module is provided. The optical module includes a lens group as described in the first aspect.

[0021] According to a third aspect of this application, an optical device is provided. The optical device includes the optical module as described in the second aspect.

[0022] One technical advantage of this application is:

[0023] The lens group provided in this application embodiment, through a specific structural design, utilizes the optical characteristics of the first lens and the second lens and their bonding method to effectively focus light and achieve off-axis transmission of light.

[0024] Other features and advantages of this specification will become clear from the following detailed description of exemplary embodiments with reference to the accompanying drawings. Attached Figure Description

[0025] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments of this specification and, together with their description, serve to explain the principles of this specification.

[0026] Figure 1 The diagram shown is an optical architecture diagram of the lens group provided in an embodiment of this application.

[0027] Explanation of reference numerals in the attached figures:

[0028] 1. First lens; 10. Incident surface; 11. First cemented surface; 12. First surface; 13. Third surface;

[0029] 2. Second lens; 20. Light-emitting surface; 21. Second cemented surface; 22. Third surface; 23. Fourth surface. Detailed Implementation

[0030] Various exemplary embodiments of this application will now be described in detail with reference to the accompanying drawings. It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of this application.

[0031] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the scope of this application and its application or use.

[0032] Technologies and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such technologies and equipment should be considered part of the specification.

[0033] In all the examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0034] It should be noted that similar labels and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be discussed further in subsequent figures.

[0035] This application provides a novel lens group that, through a specific structural design, utilizes the optical properties of the first and second lenses and their bonding method to effectively focus light and achieve off-axis light transmission.

[0036] Reference Figure 1 The optical axis includes a first lens 1 and a second lens 2, both of which are prisms. The first lens 1 satisfies the following condition:

[0037]

[0038] Where d1 is the thickness of the first lens 1 in coordinates (x, y, z), D0 is the reference thickness of the first lens 1, A is a constant, n1 is the refractive index of the first lens 1 in coordinates (x, y, z), n0 is the reference refractive index of the first lens 1, and B is a constant.

[0039] The second lens 2 satisfies:

[0040]

[0041] Where d2 is the thickness of the second lens 2 at coordinates (x, y, z), D0 is the reference thickness of the second lens 2, A is a constant, n2 is the refractive index of the second lens 2 at coordinates (x, y, z), n0 is the reference refractive index of the second lens 2, and B is a constant.

[0042] The first lens 1 and the second lens 2 are glued together, so that the lens group can focus light while enabling off-axis light transmission.

[0043] In the lens group involved in this application, for the lens itself, the optical path difference phase function can be defined as the product of the refractive index function and the thickness function, and the specific expression is as follows:

[0044]

[0045] The optical path difference equation, also known as the phase function, plays a decisive role in the direction of light rays. If the phase function contains... If the phase function contains a term, then the lens group can achieve focusing. If the first term is applied, the lens group can achieve off-axis light rays.

[0046] Based on this principle, this application defines a phase function for a novel lens, wherein the refractive index and thickness equations of the novel lens are defined as follows:

[0047] (1)

[0048] Where d is the thickness of the lens at coordinates (x, y, z), D0 is the reference thickness of the lens, A is a constant, n is the refractive index of the lens at coordinates (x, y, z), n0 is the reference refractive index of the lens, and B is a constant.

[0049] Specifically, this thickness function describes the thickness of the lens at three-dimensional spatial coordinates (x, y, z). This thickness equation shows that the lens thickness is not uniformly distributed, but changes with the coordinate y.

[0050] Where D0 represents the reference thickness of the lens, that is, the thickness of the lens when y=0, which is a basic reference value for the thickness function.

[0051] A is a constant that determines the rate at which the thickness changes with the y-coordinate. The larger the absolute value of A, the faster the lens thickness changes with the y-coordinate; when A is positive, the thickness increases with increasing y; when A is negative, the thickness decreases with increasing y.

[0052] In the field of novel lens technology involved in this application, those skilled in the art can selectively define the sign of the constant A according to the actual optical application requirements.

[0053] Specifically, when a practical optical system requires the lens thickness to increase with the y-coordinate, technicians can define the constant A as a positive value. For example, in some specific optical imaging systems, to achieve a particular light-gathering effect, the lens thickness needs to exhibit an increasing distribution in the y-direction. In this case, setting A to a positive value, the thickness function d(x, y, z) = D0 + A × y can accurately describe this thickness variation, ensuring that the lens has an appropriate thickness at different y-coordinate positions, thereby meeting the requirements of light propagation and imaging.

[0054] Conversely, when a real-world optical scenario requires the lens thickness to decrease as the y-coordinate increases, technicians can define the constant A as a negative value.

[0055] This flexible definition of the sign of the constant A fully demonstrates the flexibility and adaptability of the novel lens design proposed in this application. It enables the lens to be customized according to different optical requirements and widely used in various complex optical systems, effectively solving the problem of the lack of flexibility in thickness distribution design of traditional lenses.

[0056] The refractive index function describes the refractive index of a lens at three-dimensional coordinates (x, y, z). The refractive index is a measure of the speed of light propagation within a lens, determining the direction and path of light ray propagation. This function indicates that the refractive index distribution of the lens is related to coordinates x and y and is not uniform.

[0057] n0 represents the reference refractive index of the lens, which is the fundamental value of the refractive index function and is equivalent to the refractive index of the lens when x=0 and y=0.

[0058] B is a constant that controls the degree to which the refractive index varies with the x and y coordinates. The magnitude of B affects the curvature of the refractive index distribution, which in turn affects the propagation characteristics of light in the lens.

[0059] This part determines the distribution of the refractive index in space, thus having different effects on the specific behavior of light.

[0060] In the field of novel lens technology focused on in this application, given the diverse requirements of different optical application scenarios for light propagation characteristics, those skilled in the art can selectively define the sign of the constant B based on the actual optical application requirements.

[0061] From the perspective of optical principles, the constant B is related to the refractive index function n(x, y, z) = n0 + B × (y 2 The constant B plays a crucial role, directly affecting the refractive index's variation with coordinates x and y. When practical optical systems require light to converge or diverge in a specific manner, the appropriate choice of the sign of the constant B becomes particularly important.

[0062] This application embodiment achieves off-axis optical path simultaneously with focusing and imaging by combining two novel lenses. Specifically, two novel lenses (first lens 1 and second lens 2) are cemented together, achieving off-axis optical path while focusing and imaging.

[0063] Specifically, the first lens 1 satisfies:

[0064] (2)

[0065] The second lens 2 satisfies:

[0066] (3)

[0067] In optical systems, the primary function of a lens is to refract light, thereby changing the direction of light propagation and achieving functions such as focusing and imaging. While a single lens has a relatively limited function, combining two lenses, especially cementing them together, allows for the integration of their optical characteristics, enabling more complex and flexible light control.

[0068] In this embodiment, the thickness function of both the first lens 1 and the second lens 2 is d(x, y, z) = D0 + A × y. This indicates that the thickness of the lens in the y-direction is not uniform, but varies with the y-coordinate. The constant D0 is the reference thickness of the lens; when y = 0, the lens thickness is D0. This thickness distribution design can affect the propagation path of light in the lens, providing a structural basis for achieving off-axis optical paths.

[0069] The refractive index function of the first lens 1 is n1(x, y, z) = n0 + B × ( The reference refractive index n0 is the refractive index of the lens at the origin. The constant B controls the degree to which the refractive index changes with the x and y coordinates. When B is positive, the refractive index increases accordingly with changes in the x and y coordinates. This refractive index distribution helps light converge in a specific direction, achieving the focusing function.

[0070] The refractive index function of the second lens 2 is n2(x, y, z) = n0 - B × ( Unlike the first lens 1, when B is positive, the refractive index decreases with changes in the x and y coordinates. The different refractive index distributions of the two lenses work together to comprehensively adjust the direction of light propagation after cementation.

[0071] When the first lens 1 and the second lens 2 are cemented together, light passes through them sequentially. The refractive index distribution of the first lens 1 causes the light to converge in a certain direction, achieving a preliminary focusing effect; simultaneously, its thickness distribution also affects the propagation of the light, causing it to deviate off-axis to a certain extent. The refractive index distribution of the second lens 2 complements that of the first lens 1, further adjusting the degree of light convergence to ensure accurate focusing and imaging; its thickness distribution also plays a synergistic role in deviating the light from the axis. Through the combined action of the two lenses, both focusing and off-axis optical path are achieved, meeting the needs of specific optical applications.

[0072] According to an embodiment of this application, the lens group deflects the light in the direction of y, the deflection amount of the lens group is δ, and the optical path difference phase function of the lens group is:

[0073] (4)

[0074] In this embodiment, based on the above formulas (2) and (3) and combined with the limitations of the lens group on the direction and amount of light deflection, the optical path difference phase function of the lens group satisfies the above formula (4).

[0075] From the above formula (4), it can be seen that, in addition to the constant term, the phase function of the optical path difference of the lens group also has a relationship with (x). 2 +y 2The terms related to y fully demonstrate that this lens group, while achieving the function of focusing light, can also cause the image plane to deflect off-axis.

[0076] In optics, the optical path difference phase function is a crucial function describing the wavefront change of light after passing through an optical element, directly determining the propagation characteristics of light. For lens groups, each term in the optical path difference phase function has a specific physical meaning.

[0077] In formula (4), (x) 2 +y 2 The relevant terms are: -2×A×B×δ×(x) 2 +y 2 This term, similar in form to the term related to the square of the coordinates in the phase transformation formula of a thin lens, causes light rays to focus or diverge. In this lens group, the presence of this term causes the light rays to undergo phase modulation to varying degrees depending on their position (x, y) during propagation, thus achieving the focusing function. Specifically, this term causes the light rays to converge towards a specific point, similar to the focusing effect of a traditional lens, ensuring that the light rays can form a sharp image at the expected location.

[0078] The terms related to y in formula (4) are: These terms affect the propagation of light in the y-direction. They cause additional phase changes in the light rays in the y-direction, resulting in an off-axis deflection of the image plane in that direction. In other words, light rays that should normally image along the principal optical axis will, due to these y-related terms, cause the image plane to deviate from the principal optical axis, achieving an off-axis effect. This off-axis effect can be precisely controlled by adjusting the lens group parameters (such as A, B, δ, etc.) to meet the needs of different optical applications.

[0079] This application provides the optical path difference phase function of the lens group, which is related to (x) 2 +y 2 The combined effect of the y-related terms enables this lens group to simultaneously achieve the focusing of light rays and the off-axis deflection of the image plane.

[0080] According to an embodiment of this application, the focal length of the lens group is f = 1 / (4×A×B×δ); the off-axis amount y of the lens group off =λ / 2π×(2×n0×A-(8×D0×B×δ) / 3)×L, where L is the axial length of the lens group.

[0081] In optical systems, focal length is a parameter that measures the ability of a lens group to converge light. The optical path difference phase function OPD(x, y, z) describes the wavefront change of light after passing through the lens group, and this wavefront change directly determines the propagation path and focusing characteristics of the light. For this lens group, the optical path difference phase function is related to (x...y...z)... 2 +y 2 Related terms -2×A×B×δ×(x) 2 +y 2 It plays a crucial role in determining the focal length.

[0082] Under paraxial optics conditions, the phase transformation formula for a thin lens is Φ(x, y) = -2π / f*((x, y) 2 +y 2 ) / 2f), where f is the focal length.

[0083] After converting the optical path difference phase function of the lens group into the phase transformation function Φ(x, y, z) = 2π / f*OPD(x, y, z), a comparison reveals that the optical path difference phase function of the lens group is related to (x... 2 +y 2 The related terms have a similar function to the coordinate square term in the phase transformation formula for thin lenses. After approximation and formula derivation, ignoring the influence of higher-order terms, the relationship between the focal length f and parameters A, B, and δ is obtained as f = 1 / (4 × A × B × δ1). This shows that by adjusting the values ​​of parameters A, B, and δ, the focal length of the lens group can be precisely controlled, thereby meeting the requirements of different optical applications for the degree of light convergence.

[0084] The linear term related to y in the optical path difference phase function These are key factors causing the image plane to deviate from the principal optical axis. These linear terms cause additional phase changes in the y-direction during light propagation, thereby altering the direction of light propagation and causing the image plane to deviate from the principal optical axis.

[0085] Derivation based on the formula for ray propagation offset: According to the formula for ray propagation offset:

[0086] L, This is the partial derivative of the phase transformation function with respect to y. Taking the partial derivative of the phase transformation function of the lens group, considering the partial derivative at y=0 in the paraxial case, and combining it with the linear term related to y in the optical path difference phase function, after calculation and simplification, the off-axis quantity y is obtained. offThe expression for the off-axis distance is given. This formula shows that the off-axis distance is related not only to the optical parameters of the lens group (n0, A, D0, B, δ), but also to the axial length L of the lens group and the wavelength λ of the light. By properly adjusting these parameters, the off-axis distance of the image plane can be precisely controlled to meet the needs of specific optical applications, such as achieving precise image plane position control in some optical systems that require off-axis imaging.

[0087] According to an embodiment of this application, the offset δ of the lens group ranges from 0.1 mm to 2 mm. Preferably, the offset δ ranges from 0.5 mm to 1 mm, for example, the offset δ can be 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, and 1 mm.

[0088] From an optical principle perspective, the offset δ is closely related to the optical path difference phase function of the lens group. The optical path difference phase function determines the wavefront change of light after passing through the lens group, thus affecting the propagation direction and imaging characteristics of the light. When light passes through the lens group, the offset δ introduces a specific phase change.

[0089] If the value of δ is too small, for example, much smaller than 0.1 mm, the phase change caused by δ will be very weak. This makes the lens group's ability to control light insufficient, making it difficult to effectively achieve an off-axis effect on the image plane.

[0090] Conversely, if δ is too large, exceeding 2mm, it may cause excessively drastic changes in the optical path difference phase function. This could lead to undesirable diffraction effects and increased aberrations during light propagation, affecting image quality and potentially even preventing proper focusing of the light, thus compromising the basic function of the lens group.

[0091] Therefore, limiting the offset δ to the range of 0.1mm to 2mm is to ensure that the lens group can effectively achieve off-axis image plane while avoiding various optical problems caused by improper δ value, and to ensure that the lens group has good optical performance.

[0092] According to the embodiments of this application, refer to Figure 1 The cemented surfaces of the first lens and the second lens are both vertical planes. The lens group is provided with an incident light surface 10 and an exit light surface 20. The incident light surface 10 is a first inclined surface, and the exit light surface 20 is a second inclined surface. The first inclined surface and the second inclined surface are asymmetrically arranged.

[0093] In this embodiment, the cemented surfaces of the first and second lenses are vertical planes. This regular planar structure provides a stable basic interface for the propagation of light inside the prism. When light enters the lens group, the vertical cemented surfaces can guide the light through initial reflection or refraction as designed, allowing the light to propagate in a more regular manner inside the prism, reducing disordered scattering of light, and helping to achieve precise control over the light propagation path.

[0094] In this embodiment, the light-incident surface 10 is a first inclined plane, and the light-exiting surface 20 is a second inclined plane, and the two are asymmetrically arranged. This asymmetrical inclined plane allows for more flexible light control of the lens group. Different tilt angles and asymmetrical layouts can change the incident and exit angles of light as it enters and leaves the lens group, thereby allowing for diverse adjustments to the direction of light propagation according to actual needs. For example, in some optical systems that require light output at a specific angle, the angle and positional relationship between these two inclined planes can be adjusted to allow the light to exit at an ideal angle, meeting the optical design requirements of the system.

[0095] For example, the tilt slope of the light-incident surface 10 of the lens group is greater than the tilt slope of the light-outceasing surface 20 of the lens group.

[0096] The incident light surface 10 of the lens group has a greater tilt slope than the exit light surface 20. This differentiated slope design supports the control of the light propagation path. The larger tilt slope of the incident light surface 10 allows the light entering the lens group to be refracted with a more significant angle change, thereby rapidly altering the initial propagation direction of the light and laying the foundation for subsequent light propagation within the lens group. The relatively smaller tilt slope of the exit light surface 20, on the other hand, allows for fine-tuning of the internally adjusted light, ensuring that the light exits the lens group at an angle that meets specific requirements.

[0097] In terms of imaging, this slope difference helps improve image quality. The larger tilt slope of the incident surface 10 effectively collects and guides light, reducing light loss and scattering, allowing more light to enter the lens group and participate in the imaging process. Simultaneously, the smaller tilt slope of the exit surface 20 allows for precise control of the light exit angle, helping the light to converge more accurately on the imaging surface and reducing aberrations such as spherical aberration and coma. This slope design results in clearer, sharper images, improving image resolution and contrast, and providing a reliable guarantee for high-precision optical imaging applications.

[0098] For example, refer to Figure 1 The first lens 1 is a first hexahedral prism. The first hexahedral prism includes an incident light surface 10 as a lens group and a first bonding surface 11 bonded to the second lens 2 along the optical axis. The incident light surface 10 is an inclined plane that is inclined toward the first bonding surface 11, and the first bonding surface 11 is a vertical plane.

[0099] The first hexahedral prism includes a first reflecting surface and a second reflecting surface along a direction perpendicular to the optical axis (perpendicular to the plane of the paper) to reflect light, thereby changing the propagation path of the light.

[0100] The first hexahedral prism includes a first surface 12 and a second surface 13 arranged opposite each other along a direction perpendicular to the optical axis (vertical direction). These two surfaces, as components of the prism structure, together with the other faces of the prism, form a complete hexahedral structure and synergistically influence the propagation characteristics of light within the prism.

[0101] For example, refer to Figure 1 The second lens 2 is a second hexahedral prism. The second hexahedral prism includes a second cemented surface 21, which is combined with the first lens 1 group, and a light-emitting surface 20, which is a lens group, along the optical axis. The light-emitting surface 20 is an inclined plane that is inclined toward the cemented surface, and the second cemented surface 21 is a vertical plane.

[0102] The second hexahedral prism includes a third and a fourth reflecting surface along the direction perpendicular to the optical axis (perpendicular to the plane of the paper) to reflect light, thereby changing the propagation path of the light.

[0103] The second hexahedral prism includes a third surface 22 and a fourth surface 23 arranged opposite each other along a direction perpendicular to the optical axis (vertical direction). These two surfaces, as components of the prism structure, together with the other faces of the prism, form a complete hexahedral structure and synergistically influence the propagation characteristics of light within the prism.

[0104] According to an embodiment of this application, an optical adhesive is provided between the cemented surface of the first lens and the cemented surface of the second lens, and the refractive index of the optical adhesive is between the refractive index of the first lens 1 and the refractive index of the second lens 2.

[0105] In this embodiment, when light enters the optical adhesive from the first lens 1 and then from the optical adhesive into the second lens 2, the refractive index of the optical adhesive is between that of the two lenses. This results in a smoother change in the refraction angle at the interface, following the law of continuous refraction. This reduces light scattering and reflection caused by abrupt changes in refractive index, allowing light to propagate more smoothly within the lens group and improving light transmission efficiency. Furthermore, by using an optical adhesive with a refractive index between the two lenses for bonding, reflection at the interface is reduced, thereby suppressing the generation of stray light. This results in clearer and more accurate imaging, effectively improving the resolution and signal-to-noise ratio of the image, and meeting the requirements of high-precision optical imaging.

[0106] According to the embodiments of this application, the constants A and B satisfy the relationship 1≤A / B≤5. Such a parameter ratio helps to optimize the optical path difference phase function, making the lens group more precise in focusing and controlling off-axis light, and improving the optical efficiency of the lens group.

[0107] In this embodiment, a reasonable A / B ratio (1≤A / B≤5) can make the optical path difference phase function of the lens group reach an ideal distribution state, ensuring that the light converges and deflects according to the expected path during propagation, thereby ensuring that the lens group has stable and good focusing imaging and off-axis optical path effect, and meeting the basic requirements of the optical system for light control.

[0108] According to an embodiment of this application, the lens group can focus light with a spot diameter of less than 5μm within the working wavelength range, thereby achieving high-precision light focusing.

[0109] In this lens group structure, the materials constituting the first lens 1 and the second lens 2 are low-dispersion optical glass with an Abbe number greater than 60. The low-dispersion characteristics can reduce chromatic aberration when light passes through the lens group, thereby improving image quality or the accuracy of optical signal transmission.

[0110] In this lens group structure, the materials of the first lens 1 and the second lens 2 have high light transmittance, with a light transmittance of more than 95% in the visible light band. High light transmittance can reduce the absorption loss of light in the lens group and improve the utilization rate of light energy.

[0111] According to a second aspect of the present application, an optical module is provided. The optical module includes a lens group as described in the first aspect.

[0112] According to an embodiment of this application, an optical module including the above-mentioned lens group is provided, which can achieve both focusing of light and off-axis transmission of light.

[0113] According to a third aspect of this application, an optical device is provided. The optical device includes the optical module as described in the second aspect.

[0114] For example, the optical device can be a laser marking device, which is used to focus and control the laser beam off-axis to achieve high-precision marking operations and improve the quality and efficiency of marking.

[0115] For example, the optical device can be an optical projection device. This optical projection device has the function of achieving light focusing and off-axis effects, that is, it can converge light according to preset requirements and deviate the imaging light path from the principal optical axis to meet the relevant application requirements of optical projection.

[0116] For example, the optical device can be an optical interferometry device, which improves the accuracy and resolution of interferometry by controlling the optical path difference and off-axis characteristics of light rays.

[0117] The above embodiments mainly describe the differences between the various embodiments. As long as the different optimization features between the various embodiments are not contradictory, they can be combined to form a better embodiment. For the sake of brevity, they will not be elaborated here.

[0118] While specific embodiments of this application have been described in detail by way of examples, those skilled in the art should understand that the above examples are for illustrative purposes only and are not intended to limit the scope of this application. Those skilled in the art should understand that modifications can be made to the above embodiments without departing from the scope and spirit of this application. The scope of this application is defined by the appended claims.

Claims

1. A lens assembly, characterized in that, The optical axis includes a first lens (1) and a second lens (2) in sequence. Both the first lens (1) and the second lens (2) are prisms. The first lens (1) satisfies the following condition: Wherein, d1 is the thickness of the first lens (1) in coordinates (x, y, z), D0 is the reference thickness of the first lens (1), A is a constant, n1 is the refractive index of the first lens (1) in coordinates (x, y, z), n0 is the reference refractive index of the first lens (1), and B is a constant. The second lens (2) satisfies: Where d2 is the thickness of the second lens (2) at coordinates (x, y, z), D0 is the reference thickness of the second lens (2), A is a constant, n2 is the refractive index of the second lens (2) at coordinates (x, y, z), n0 is the reference refractive index of the second lens (2), and B is a constant; The vertical planes of the first lens (1) and the second lens (2) are glued together, so that the lens group can focus light while realizing off-axis light transmission; The lens group deflects the light rays in the direction of y, the deflection amount of the lens group is δ, and the optical path difference phase function of the lens group is: 。 2. The lens assembly according to claim 1, characterized in that, The focal length of the lens group is f = 1 / (4×A×B×δ); the off-axis displacement of the lens group is yoff = λ / 2π×(2×n0×A). (8×D0×B×δ) / 3)×L, where L is the axial length of the lens group.

3. The lens assembly according to claim 1, characterized in that, The offset δ of the lens group ranges from 0.1 mm to 2 mm.

4. The lens assembly according to claim 1, characterized in that, An optical adhesive is provided between the cemented surfaces of the first lens and the second lens, and the refractive index of the optical adhesive is between the refractive index of the first lens (1) and the refractive index of the second lens (2).

5. The lens assembly according to any one of claims 1-4, characterized in that, The constants A and B satisfy the relationship 1≤A / B≤5.

6. The lens assembly according to any one of claims 1-4, characterized in that, Within the operating wavelength range, the lens group focuses light onto a spot with a diameter of less than 5 μm.

7. An optical module, characterized in that, The optical module includes a lens group as described in any one of claims 1-6.

8. An optical device, characterized in that, The optical device includes the optical module as described in claim 7.

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