WO2019100671A1 - 投影镜头 - Google Patents

投影镜头 Download PDF

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Publication number
WO2019100671A1
WO2019100671A1 PCT/CN2018/087037 CN2018087037W WO2019100671A1 WO 2019100671 A1 WO2019100671 A1 WO 2019100671A1 CN 2018087037 W CN2018087037 W CN 2018087037W WO 2019100671 A1 WO2019100671 A1 WO 2019100671A1
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Prior art keywords
lens
projection lens
projection
image
imaging
Prior art date
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PCT/CN2018/087037
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English (en)
French (fr)
Inventor
黄林
王新权
Original Assignee
浙江舜宇光学有限公司
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from CN201721562706.2U external-priority patent/CN207780339U/zh
Priority claimed from CN201711166983.6A external-priority patent/CN107728295B/zh
Application filed by 浙江舜宇光学有限公司 filed Critical 浙江舜宇光学有限公司
Priority to US16/231,147 priority Critical patent/US10996433B2/en
Publication of WO2019100671A1 publication Critical patent/WO2019100671A1/zh

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    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B13/00—Optical objectives specially designed for the purposes specified below
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
    • G03B21/00—Projectors or projection-type viewers; Accessories therefor

Definitions

  • the present application relates to a projection lens, and more particularly, to a projection lens including two lenses.
  • Conventional projection lenses for imaging generally eliminate various aberrations and increase resolution by increasing the number of lenses.
  • increasing the number of lenses causes an increase in the total optical length of the projection lens, which is disadvantageous for miniaturization of the lens.
  • the general projection lens also has many problems such as large distortion and poor image quality.
  • the present application provides a projection lens that can be adapted for use in a portable electronic product that can at least solve or partially address at least one of the above disadvantages of the prior art.
  • the present application provides a projection lens that includes, in order from the source side to the imaging side along the optical axis, a first lens and a second lens.
  • the first lens may have a negative power
  • the image source side surface may be a concave surface
  • the imaging side surface may be a convex surface
  • the second lens may have a positive power
  • the image forming side surface may be a convex surface.
  • the object side numerical aperture NA of the projection lens can satisfy NA ⁇ 0.18.
  • the maximum half angle of view HFOV of the projection lens can satisfy HFOV ⁇ 15°.
  • the optical total length TTL of the projection lens can satisfy 3 mm ⁇ TTL ⁇ 3.7 mm.
  • the light transmittance of the projection lens may be greater than 85% in the light wave band of 800 nm to 1000 nm.
  • the effective focal length f2 of the second lens and the total effective focal length f of the projection lens may satisfy 0.7 ⁇ f2 / f ⁇ 1.2.
  • the radius of curvature R4 of the imaging side surface of the second lens and the total effective focal length f of the projection lens may satisfy -0.6 ⁇ R4 / f ⁇ -0.2.
  • the radius of curvature R2 of the image forming side surface of the first lens and the radius of curvature R1 of the image source side surface of the first lens may satisfy (R2-R1)/(R2+R1) ⁇ 0.5.
  • the effective half aperture DT22 of the imaging side surface of the second lens and the effective half aperture DT21 of the image source side surface of the second lens may satisfy 1.0 ⁇ DT22 / DT21 ⁇ 1.3.
  • the present application also provides a projection lens that sequentially includes, along the optical axis, from the source side to the imaging side: a first lens and a second lens.
  • the first lens may have a negative refractive power
  • the image source side surface may be a concave surface
  • the imaging side surface may be a convex surface
  • the second lens may have a positive power
  • the imaging side surface may be a convex surface
  • the projection lens The total optical length TTL can meet 3mm ⁇ TTL ⁇ 3.7mm.
  • the present application also provides a projection lens that sequentially includes, along the optical axis, from the source side to the imaging side: a first lens and a second lens.
  • the first lens may have a negative refractive power
  • the image source side surface may be a concave surface
  • the imaging side surface may be a convex surface
  • the second lens may have a positive power
  • the imaging side surface may be a convex surface
  • the projection lens The maximum half angle of view HFOV can satisfy HFOV ⁇ 15°.
  • the present application also provides a projection lens that sequentially includes, along the optical axis, from the source side to the imaging side: a first lens and a second lens.
  • the first lens may have negative optical power
  • the image source side surface may be concave
  • the imaging side surface may be convex
  • the second lens may have positive power
  • the imaging side surface may be convex
  • the light transmittance of the projection lens can be greater than 85%.
  • the present application also provides a projection lens that sequentially includes, along the optical axis, from the source side to the imaging side: a first lens and a second lens.
  • the first lens may have a negative power
  • the image source side surface may be a concave surface
  • the imaging side surface may be a convex surface
  • the second lens may have a positive power
  • the imaging side surface may be a convex surface
  • the second The radius of curvature R4 of the imaging side surface of the lens and the total effective focal length f of the projection lens may satisfy -0.6 ⁇ R4/f ⁇ -0.2.
  • the present application also provides a projection lens that sequentially includes, along the optical axis, from the source side to the imaging side: a first lens and a second lens.
  • the first lens may have a negative power
  • the image source side surface may be a concave surface
  • the imaging side surface may be a convex surface
  • the second lens may have a positive power
  • the imaging side surface may be a convex surface
  • the second The effective half aperture DT22 of the imaging side surface of the lens and the effective half aperture DT21 of the image source side surface of the second lens may satisfy 1.0 ⁇ DT22 / DT21 ⁇ 1.3.
  • a plurality of (for example, two) lenses are used, and the projection lens is miniaturized by appropriately distributing the power, the surface shape, the center thickness of each lens, and the on-axis spacing between the lenses. At least one beneficial effect such as large numerical aperture and high imaging quality.
  • FIG. 1 is a schematic structural view of a projection lens according to Embodiment 1 of the present application.
  • 2A to 2B respectively show distortion curves and magnification chromatic aberration curves of the projection lens of Embodiment 1;
  • FIG. 3 is a schematic structural view of a projection lens according to Embodiment 2 of the present application.
  • 4A to 4B respectively show distortion curves and magnification chromatic aberration curves of the projection lens of Embodiment 2;
  • FIG. 5 is a schematic structural diagram of a projection lens according to Embodiment 3 of the present application.
  • 6A to 6B respectively show distortion curves and magnification chromatic aberration curves of the projection lens of Embodiment 3;
  • FIG. 7 is a schematic structural diagram of a projection lens according to Embodiment 4 of the present application.
  • 8A to 8B respectively show distortion curves and magnification chromatic aberration curves of the projection lens of Embodiment 4;
  • FIG. 9 is a schematic structural diagram of a projection lens according to Embodiment 5 of the present application.
  • 10A to 10B show distortion curves and magnification chromatic aberration curves of the projection lens of Embodiment 5.
  • first, second, etc. are used to distinguish one feature from another, and do not represent any limitation of the feature.
  • first lens discussed below may also be referred to as a second lens
  • second lens may also be referred to as a first lens, without departing from the teachings of the present application.
  • the thickness, size, and shape of the lens have been somewhat exaggerated for convenience of explanation.
  • the spherical or aspherical shape shown in the drawings is shown by way of example. That is, the shape of the spherical surface or the aspherical surface is not limited to the spherical or aspherical shape shown in the drawings.
  • the drawings are only examples and are not to scale.
  • a paraxial region refers to a region near the optical axis. If the surface of the lens is convex and the position of the convex surface is not defined, it indicates that the surface of the lens is convex at least in the paraxial region; if the surface of the lens is concave and the position of the concave surface is not defined, it indicates that the surface of the lens is at least in the paraxial region. Concave.
  • the surface closest to the image source side in each lens is referred to as an image source side surface, and the surface closest to the image side in each lens is referred to as an image side surface.
  • a projection lens according to an exemplary embodiment of the present application may include, for example, two lenses having power, that is, a first lens and a second lens.
  • the two lenses are sequentially arranged from the source side to the image side along the optical axis.
  • the first lens may have a negative power
  • the image side surface is a concave surface
  • the imaging side surface is a convex surface
  • the second lens has a positive power
  • the image forming side surface is a convex surface
  • the projection lens of the present application may satisfy the conditional formula HFOV ⁇ 15°, where HFOV is the maximum half angle of view of the projection lens. More specifically, HFOV can further satisfy 8 ° ⁇ HFOV ⁇ 12 °, for example, 8.5 ° ⁇ HFOV ⁇ 11.3 °. Satisfying the conditional HFOV ⁇ 15° is beneficial to control the reduction of the aberration of the off-axis field of view and improve the projection quality. At the same time, it is also beneficial to improve the uniformity of the imaging quality and the projection focus of the on-axis field of view and the off-axis field of view. deep.
  • the projection lens of the present application may satisfy the conditional expression 3 mm ⁇ TTL ⁇ 3.7 mm, where TTL is the total optical length of the projection lens.
  • the total optical length of the projection lens refers to the distance from the center of the imaging side surface of the second lens to the image source (e.g., the surface of the spatial light modulator for modulating the projection signal) on the optical axis.
  • the TTL can further satisfy 3.25 mm ⁇ TTL ⁇ 3.51 mm.
  • the conditional expression of 3 mm ⁇ TTL ⁇ 3.7 mm is satisfied, which is advantageous for miniaturization of the projection lens, thereby facilitating the projection lens to be more widely used in various portable electronic products.
  • the projection lens of the present application may satisfy the conditional expression 0.7 ⁇ f2/f ⁇ 1.2, where f2 is the effective focal length of the second lens and f is the total effective focal length of the projection lens. More specifically, f2 and f can further satisfy 0.80 ⁇ f2 / f ⁇ 1.16. Reasonable control of the power of the second lens facilitates the miniaturization of the lens and the quality of the projected image.
  • the projection lens has a large numerical aperture to increase the projection energy efficiency, resulting in a higher brightness projection image.
  • the projection lens of the present application has a light transmittance of greater than 85% in a light wave band of about 800 nm to about 1000 nm. Such a setting is advantageous for improving the transmittance of near-infrared light through the projection lens, thereby obtaining a higher-intensity near-infrared projection image.
  • the projection lens of the present application may satisfy the conditional expression -0.6 ⁇ R4 / f ⁇ - 0.2, where R4 is the radius of curvature of the imaging side surface of the second lens, and f is the total effective focal length of the projection lens. More specifically, R4 and f can further satisfy -0.54 ⁇ R4 / f ⁇ -0.30. Reasonable control of the ratio of R4 and f is beneficial to reduce the astigmatism of the projection lens and improve the quality of projection imaging.
  • the projection lens of the present application may satisfy the conditional expression (R2-R1) / (R2+R1) ⁇ 0.5, where R2 is the radius of curvature of the imaging side surface of the first lens, and R1 is the first lens The radius of curvature of the source side surface. More specifically, R2 and R1 may further satisfy 0 ⁇ (R2 - R1) / (R2 + R1) ⁇ 0.5, for example, 0.13 ⁇ (R2 - R1) / (R2 + R1) ⁇ 0.47. Satisfying the conditional expression (R2-R1)/(R2+R1) ⁇ 0.5 is advantageous for the fabrication of the first lens; at the same time, it is also possible to avoid an increase in tolerance sensitivity due to a too small radius of curvature.
  • the projection lens of the present application may satisfy the conditional expression 1.0 ⁇ DT22/DT21 ⁇ 1.3, wherein DT22 is the effective half aperture of the imaging side surface of the second lens, and DT21 is the image source side surface of the second lens. Effective half-caliber. More specifically, DT22 and DT21 can further satisfy 1.05 ⁇ DT22 / DT21 ⁇ 1.19. Satisfying the conditional expression 1.0 ⁇ DT22/DT21 ⁇ 1.3 is beneficial to avoid the degradation of the image quality caused by excessive bending of the light; at the same time, it is also advantageous to avoid problems such as difficulty in processing and manufacturing caused by high tolerance sensitivity.
  • the above projection lens may further include at least one aperture to enhance the imaging quality of the lens.
  • the aperture can be placed at any position as desired, for example, the aperture can be disposed between the second lens and the imaging side.
  • the above projection lens may further include other well-known optical projection elements such as prisms, field mirrors and the like.
  • the projection lens according to the above embodiment of the present application can employ, for example, two lenses, and the projection lens has the projection lens by rationally distributing the power of each lens, the surface shape, the center thickness of each lens, and the on-axis spacing between the lenses. At least one beneficial effect such as miniaturization, large numerical aperture, low sensitivity, and high image quality.
  • At least one of the mirror faces of each lens is an aspherical mirror.
  • the aspherical lens is characterized by a continuous change in curvature from the center of the lens to the periphery of the lens. Unlike a spherical lens having a constant curvature from the center of the lens to the periphery of the lens, the aspherical lens has better curvature radius characteristics, and has the advantages of improving distortion and improving astigmatic aberration. With an aspherical lens, the aberrations that occur during imaging can be eliminated as much as possible, improving image quality.
  • the various results and advantages described in this specification can be obtained without varying the number of lenses that make up the projection lens without departing from the technical solutions claimed herein.
  • the projection lens is not limited to including two lenses.
  • the projection lens can also include other numbers of lenses if desired.
  • FIG. 1 is a block diagram showing the structure of a projection lens according to Embodiment 1 of the present application.
  • a projection lens sequentially includes, along the optical axis, from the image source side to the imaging side: a first lens E1, a second lens E2, and a stop STO.
  • the first lens E1 has a negative refractive power
  • the image side surface S1 is a concave surface
  • the imaging side surface S2 is a convex surface.
  • the second lens E2 has a positive power
  • the image side surface S3 is a concave surface
  • the imaging side surface S4 is a convex surface.
  • the light transmittance of the projection lens is greater than 85%.
  • Light from the image source sequentially passes through the respective surfaces S1 to S4 and is finally imaged on an imaging surface such as a projection screen (not shown).
  • Table 1 shows the surface type, radius of curvature, thickness, material, and conical coefficient of each lens of the projection lens of Example 1, in which the unit of curvature radius and thickness are both millimeters (mm).
  • each aspherical lens can be defined by using, but not limited to, the following aspherical formula:
  • x is the distance of the aspherical surface at height h from the optical axis, and the distance from the aspherical vertex is high;
  • k is the conic coefficient (given in Table 1);
  • Ai is the correction coefficient of the a-th order of the aspherical surface.
  • Table 2 gives the high order term coefficients A 4 , A 6 , A 8 , A 10 and A 12 which can be used for the respective aspherical mirror faces S1 - S4 in the embodiment 1.
  • Table 3 gives the total effective focal length f of the projection lens in Embodiment 1, the effective focal lengths f1 and f2 of each lens, the optical total length TTL of the projection lens, the maximum half angle of view HFOV of the projection lens, and the object-side numerical aperture of the projection lens. NA.
  • the projection lens in Embodiment 1 satisfies:
  • F2/f 0.92, where f2 is the effective focal length of the second lens E2, and f is the total effective focal length of the projection lens;
  • R4/f -0.44, where R4 is the radius of curvature of the imaging side surface S4 of the second lens E2, and f is the total effective focal length of the projection lens;
  • R2-R1)/(R2+R1) 0.28, where R2 is the radius of curvature of the image side surface S2 of the first lens E1, and R1 is the radius of curvature of the image source side surface S1 of the first lens E1;
  • DT22/DT21 1.08, where DT22 is the effective half aperture of the imaging side surface S4 of the second lens E2, and DT21 is the effective half aperture of the image source side surface S3 of the second lens E2.
  • 2A shows a distortion curve of the projection lens of Embodiment 1, which shows distortion magnitude values in the case of different viewing angles.
  • 2B shows a magnification chromatic aberration curve of the projection lens of Embodiment 1, which indicates a deviation of different image heights on the imaging plane after the light passes through the lens.
  • the projection lens given in Embodiment 1 can achieve good image quality.
  • FIG. 3 is a schematic structural view of a projection lens according to Embodiment 2 of the present application.
  • a projection lens sequentially includes, along the optical axis, from the image source side to the imaging side: a first lens E1, a second lens E2, and a stop STO.
  • the first lens E1 has a negative refractive power
  • the image side surface S1 is a concave surface
  • the imaging side surface S2 is a convex surface.
  • the second lens E2 has a positive power
  • the image side surface S3 is a convex surface
  • the image forming side surface S4 is a convex surface.
  • the light transmittance of the projection lens is greater than 85%.
  • Light from the image source sequentially passes through the respective surfaces S1 to S4 and is finally imaged on an imaging surface such as a projection screen (not shown).
  • Table 4 shows the surface type, the radius of curvature, the thickness, the material, and the conical coefficient of each lens of the projection lens of Example 2, wherein the unit of the radius of curvature and the thickness are each mm (mm).
  • the image source side surface S1 and the image forming side surface S2 of the first lens E1 and the image source side surface S3 and the image forming side surface S4 of the second lens E2 are both aspherical.
  • Table 5 shows the high order coefficient which can be used for each aspherical mirror in Embodiment 2, wherein each aspherical surface type can be defined by the formula (1) given in the above Embodiment 1.
  • Table 6 gives the effective focal lengths f1 and f2 of each lens in Embodiment 2, the total effective focal length f of the projection lens, the optical total length TTL of the projection lens, the maximum half angle of view HFOV of the projection lens, and the object-side numerical aperture of the projection lens. NA.
  • 4A shows a distortion curve of the projection lens of Embodiment 2, which shows distortion magnitude values in the case of different viewing angles.
  • 4B shows a magnification chromatic aberration curve of the projection lens of Embodiment 2, which shows deviations of different image heights on the imaging plane after the light passes through the lens. 4A to 4B, the projection lens given in Embodiment 2 can achieve good image quality.
  • FIG. 5 is a schematic structural view of a projection lens according to Embodiment 3 of the present application.
  • a projection lens sequentially includes, along the optical axis, from the image source side to the imaging side: a first lens E1, a second lens E2, and a stop STO.
  • the first lens E1 has a negative refractive power
  • the image side surface S1 is a concave surface
  • the imaging side surface S2 is a convex surface.
  • the second lens E2 has a positive power
  • the image side surface S3 is a concave surface
  • the imaging side surface S4 is a convex surface.
  • the light transmittance of the projection lens is greater than 85%.
  • Light from the image source sequentially passes through the respective surfaces S1 to S4 and is finally imaged on an imaging surface such as a projection screen (not shown).
  • Table 7 shows the surface type, the radius of curvature, the thickness, the material, and the conical coefficient of each lens of the projection lens of Example 3, wherein the units of the radius of curvature and the thickness are each mm (mm).
  • the image source side surface S1 and the image forming side surface S2 of the first lens E1 and the image source side surface S3 and the image forming side surface S4 of the second lens E2 are both aspherical.
  • Table 8 shows the high order term coefficients which can be used for the respective aspherical mirrors in Embodiment 3, wherein each aspherical surface type can be defined by the formula (1) given in the above Embodiment 1.
  • Table 9 gives the effective focal lengths f1 and f2 of each lens in Embodiment 3, the total effective focal length f of the projection lens, the optical total length TTL of the projection lens, the maximum half angle of view HFOV of the projection lens, and the object-side numerical aperture of the projection lens. NA.
  • Fig. 6A shows a distortion curve of the projection lens of Embodiment 3, which shows distortion magnitude values in the case of different viewing angles.
  • Fig. 6B shows a magnification chromatic aberration curve of the projection lens of Embodiment 3, which shows deviations of different image heights on the imaging plane after the light passes through the lens. 6A to 6B, the projection lens given in Embodiment 3 can achieve good image quality.
  • FIG. 7 is a block diagram showing the structure of a projection lens according to Embodiment 4 of the present application.
  • a projection lens sequentially includes, along the optical axis, from the image source side to the imaging side: a first lens E1, a second lens E2, and a stop STO.
  • the first lens E1 has a negative refractive power
  • the image side surface S1 is a concave surface
  • the imaging side surface S2 is a convex surface.
  • the second lens E2 has a positive power
  • the image side surface S3 is a concave surface
  • the imaging side surface S4 is a convex surface.
  • the light transmittance of the projection lens is greater than 85%.
  • Light from the image source sequentially passes through the respective surfaces S1 to S4 and is finally imaged on an imaging surface such as a projection screen (not shown).
  • Table 10 shows the surface type, the radius of curvature, the thickness, the material, and the conical coefficient of each lens of the projection lens of Example 4, wherein the unit of the radius of curvature and the thickness are each mm (mm).
  • the image source side surface S1 and the image forming side surface S2 of the first lens E1 and the image source side surface S3 and the image forming side surface S4 of the second lens E2 are both aspherical.
  • Table 11 shows the high order coefficient which can be used for each aspherical mirror in Embodiment 4, wherein each aspherical surface type can be defined by the formula (1) given in the above Embodiment 1.
  • Table 12 gives the effective focal lengths f1 and f2 of each lens in Embodiment 4, the total effective focal length f of the projection lens, the optical total length TTL of the projection lens, the maximum half angle of view HFOV of the projection lens, and the object-side numerical aperture of the projection lens. NA.
  • Fig. 8A shows a distortion curve of the projection lens of Embodiment 4, which shows distortion magnitude values in the case of different viewing angles.
  • Fig. 8B shows a magnification chromatic aberration curve of the projection lens of Embodiment 4, which shows deviations of different image heights on the imaging plane after the light passes through the lens. 8A to 8B, the projection lens given in Embodiment 4 can achieve good image quality.
  • FIG. 9 is a block diagram showing the structure of a projection lens according to Embodiment 5 of the present application.
  • a projection lens sequentially includes, along the optical axis, from the image source side to the imaging side: a first lens E1, a second lens E2, and a stop STO.
  • the first lens E1 has a negative refractive power
  • the image side surface S1 is a concave surface
  • the imaging side surface S2 is a convex surface.
  • the second lens E2 has a positive power
  • the image side surface S3 is a concave surface
  • the imaging side surface S4 is a convex surface.
  • the light transmittance of the projection lens is greater than 85%.
  • Light from the image source sequentially passes through the respective surfaces S1 to S4 and is finally imaged on an imaging surface such as a projection screen (not shown).
  • Table 13 shows the surface type, radius of curvature, thickness, material, and conical coefficient of each lens of the projection lens of Example 5, in which the unit of the radius of curvature and the thickness are each mm (mm).
  • the image source side surface S1 and the image forming side surface S2 of the first lens E1 and the image source side surface S3 and the image forming side surface S4 of the second lens E2 are both aspherical.
  • Table 14 shows the high order coefficient which can be used for each aspherical mirror surface in Embodiment 5, wherein each aspherical surface type can be defined by the formula (1) given in the above Embodiment 1.
  • Table 15 gives the effective focal lengths f1 and f2 of each lens in Embodiment 5, the total effective focal length f of the projection lens, the optical total length TTL of the projection lens, the maximum half angle of view HFOV of the projection lens, and the object-side numerical aperture of the projection lens. NA.
  • Fig. 10A shows a distortion curve of the projection lens of Embodiment 5, which shows distortion magnitude values in the case of different viewing angles.
  • Fig. 10B shows a magnification chromatic aberration curve of the projection lens of Embodiment 5, which shows deviations of different image heights on the imaging plane after the light passes through the lens. 10A to 10B, the projection lens given in Embodiment 5 can achieve good image quality.
  • Embodiments 1 to 5 respectively satisfy the relationship shown in Table 16.

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Abstract

一种投影镜头，镜头沿光轴由像源侧至成像侧依序包括：第一透镜(E1)和第二透镜(E2)。其中，第一透镜(E1)具有负光焦度，其像源侧表面(S1)为凹面，成像侧表面(S2)为凸面；第二透镜(E2)具有正光焦度，其成像侧表面(S4)为凸面。

Description

投影镜头
相关申请的交叉引用
本申请要求于2017年11月21日提交于中国国家知识产权局(SIPO)的、专利申请号为201711166983.6的中国专利申请以及于2017年11月21日提交至SIPO的、专利申请号为201721562706.2的中国专利申请的优先权和权益，以上中国专利申请通过引用整体并入本文。
技术领域
本申请涉及一种投影镜头，更具体地，本申请涉及一种包括两片透镜的投影镜头。
背景技术
随着科技的快速发展，交互设备逐步兴起，投影镜头的应用范围也越来越广。如今，芯片技术与智能算法发展迅速，利用光学投影镜头向空间物体投射图像并接收该图像信号，即可计算出具有位置深度信息的三维图像。具有深度信息的三维图像可进一步用于生物识别等多种深度应用开发中。
用于成像的传统投影镜头，通常通过采用增加透镜数量的方式来消除各种像差并提高分辨率。但是，增加透镜数量会导致投影镜头的光学总长度增加，从而不利于实现镜头的小型化。另外，一般的投影镜头还会存在畸变量大、成像质量差等诸多问题。
发明内容
本申请提供了可适用于便携式电子产品的、可至少解决或部分解决现有技术中的上述至少一个缺点的投影镜头。
一方面，本申请提供了这样一种投影镜头，该镜头沿光轴由像源侧至成像侧依序包括：第一透镜和第二透镜。其中，第一透镜可具有负光焦度，其像源侧表面可为凹面，成像侧表面可为凸面；第二透镜 可具有正光焦度，其成像侧表面可为凸面。
在一个实施方式中，投影镜头的物方数值孔径NA可满足NA≥0.18。
在一个实施方式中，投影镜头的最大半视场角HFOV可满足HFOV＜15°。
在一个实施方式中，投影镜头的光学总长度TTL可满足3mm＜TTL＜3.7mm。
在一个实施方式中，在800nm至1000nm的光波波段中，投影镜头的光线透过率可大于85％。
在一个实施方式中，第二透镜的有效焦距f2与投影镜头的总有效焦距f可满足0.7＜f2/f＜1.2。
在一个实施方式中，第二透镜的成像侧表面的曲率半径R4与投影镜头的总有效焦距f可满足-0.6＜R4/f＜-0.2。
在一个实施方式中，第一透镜的成像侧表面的曲率半径R2与第一透镜的像源侧表面的曲率半径R1可满足(R2-R1)/(R2+R1)＜0.5。
在一个实施方式中，第二透镜的成像侧表面的有效半口径DT22与第二透镜的像源侧表面的有效半口径DT21可满足1.0＜DT22/DT21＜1.3。
另一方面，本申请还提供了这样一种投影镜头，该镜头沿光轴由像源侧至成像侧依序包括：第一透镜和第二透镜。其中，第一透镜可具有负光焦度，其像源侧表面可为凹面，成像侧表面可为凸面；第二透镜可具有正光焦度，其成像侧表面可为凸面；以及其中，投影镜头的光学总长度TTL可满足3mm＜TTL＜3.7mm。
又一方面，本申请还提供了这样一种投影镜头，该镜头沿光轴由像源侧至成像侧依序包括：第一透镜和第二透镜。其中，第一透镜可具有负光焦度，其像源侧表面可为凹面，成像侧表面可为凸面；第二透镜可具有正光焦度，其成像侧表面可为凸面；以及其中，投影镜头的最大半视场角HFOV可满足HFOV＜15°。
又一方面，本申请还提供了这样一种投影镜头，该镜头沿光轴由像源侧至成像侧依序包括：第一透镜和第二透镜。其中，第一透镜可 具有负光焦度，其像源侧表面可为凹面，成像侧表面可为凸面；第二透镜可具有正光焦度，其成像侧表面可为凸面；以及其中，在800nm至1000nm的光波波段中，投影镜头的光线透过率可大于85％。
又一方面，本申请还提供了这样一种投影镜头，该镜头沿光轴由像源侧至成像侧依序包括：第一透镜和第二透镜。其中，第一透镜可具有负光焦度，其像源侧表面可为凹面，成像侧表面可为凸面；第二透镜可具有正光焦度，其成像侧表面可为凸面；以及其中，第二透镜的成像侧表面的曲率半径R4与投影镜头的总有效焦距f可满足-0.6＜R4/f＜-0.2。
又一方面，本申请还提供了这样一种投影镜头，该镜头沿光轴由像源侧至成像侧依序包括：第一透镜和第二透镜。其中，第一透镜可具有负光焦度，其像源侧表面可为凹面，成像侧表面可为凸面；第二透镜可具有正光焦度，其成像侧表面可为凸面；以及其中，第二透镜的成像侧表面的有效半口径DT22与第二透镜的像源侧表面的有效半口径DT21可满足1.0＜DT22/DT21＜1.3。
本申请采用了多片(例如，两片)透镜，通过合理分配各透镜的光焦度、面型、各透镜的中心厚度以及各透镜之间的轴上间距等，使得上述投影镜头具有小型化、大数值孔径、高成像品质等至少一个有益效果。
附图说明
结合附图，通过以下非限制性实施方式的详细描述，本申请的其他特征、目的和优点将变得更加明显。在附图中：
图1示出了根据本申请实施例1的投影镜头的结构示意图；
图2A至图2B分别示出了实施例1的投影镜头的畸变曲线以及倍率色差曲线；
图3示出了根据本申请实施例2的投影镜头的结构示意图；
图4A至图4B分别示出了实施例2的投影镜头的畸变曲线以及倍率色差曲线；
图5示出了根据本申请实施例3的投影镜头的结构示意图；
图6A至图6B分别示出了实施例3的投影镜头的畸变曲线以及倍率色差曲线；
图7示出了根据本申请实施例4的投影镜头的结构示意图；
图8A至图8B分别示出了实施例4的投影镜头的畸变曲线以及倍率色差曲线；
图9示出了根据本申请实施例5的投影镜头的结构示意图；
图10A至图10B示出了实施例5的投影镜头的畸变曲线以及倍率色差曲线。
具体实施方式
为了更好地理解本申请，将参考附图对本申请的各个方面做出更详细的说明。应理解，这些详细说明只是对本申请的示例性实施方式的描述，而非以任何方式限制本申请的范围。在说明书全文中，相同的附图标号指代相同的元件。表述“和/或”包括相关联的所列项目中的一个或多个的任何和全部组合。
应注意，在本说明书中，第一、第二等的表述仅用于将一个特征与另一个特征区分开来，而不表示对特征的任何限制。因此，在不背离本申请的教导的情况下，下文中讨论的第一透镜也可被称作第二透镜，第二透镜也可被称作第一透镜。
在附图中，为了便于说明，已稍微夸大了透镜的厚度、尺寸和形状。具体来讲，附图中所示的球面或非球面的形状通过示例的方式示出。即，球面或非球面的形状不限于附图中示出的球面或非球面的形状。附图仅为示例而并非严格按比例绘制。
在本文中，近轴区域是指光轴附近的区域。若透镜表面为凸面且未界定该凸面位置时，则表示该透镜表面至少于近轴区域为凸面；若透镜表面为凹面且未界定该凹面位置时，则表示该透镜表面至少于近轴区域为凹面。每个透镜中最靠近像源侧的表面称为像源侧表面，每个透镜中最靠近成像侧的表面称为成像侧表面。
还应理解的是，用语“包括”、“包括有”、“具有”、“包含”和/或“包含有”，当在本说明书中使用时表示存在所陈述的特征、元件和 /或部件，但不排除存在或附加有一个或多个其它特征、元件、部件和/或它们的组合。此外，当诸如“...中的至少一个”的表述出现在所列特征的列表之后时，修饰整个所列特征，而不是修饰列表中的单独元件。此外，当描述本申请的实施方式时，使用“可”表示“本申请的一个或多个实施方式”。并且，用语“示例性的”旨在指代示例或举例说明。
除非另外限定，否则本文中使用的所有用语(包括技术用语和科学用语)均具有与本申请所属领域普通技术人员的通常理解相同的含义。还应理解的是，用语(例如在常用词典中定义的用语)应被解释为具有与它们在相关技术的上下文中的含义一致的含义，并且将不被以理想化或过度正式意义解释，除非本文中明确如此限定。
需要说明的是，在不冲突的情况下，本申请中的实施例及实施例中的特征可以相互组合。下面将参考附图并结合实施例来详细说明本申请。
以下对本申请的特征、原理和其他方面进行详细描述。
根据本申请示例性实施方式的投影镜头可包括例如两片具有光焦度的透镜，即，第一透镜和第二透镜。这两片透镜沿着光轴由像源侧至成像侧依序排列。
在示例性实施方式中，第一透镜可具有负光焦度，其像源侧表面为凹面，成像侧表面为凸面；第二透镜具有正光焦度，其成像侧表面为凸面。
在示例性实施方式中，本申请的投影镜头可满足条件式HFOV＜15°，其中，HFOV为投影镜头的最大半视场角。更具体地，HFOV进一步可满足8°＜HFOV＜12°，例如，8.5°≤HFOV≤11.3°。满足条件式HFOV＜15°有利于控制减小轴外视场区域的像差并提升投影品质；同时，还有利于提升轴上视场区域与轴外视场区域成像质量的均匀性和投影焦深。
在示例性实施方式中，本申请的投影镜头可满足条件式3mm＜TTL＜3.7mm，其中，TTL为投影镜头的光学总长度。投影镜头的光学总长度是指从第二透镜的成像侧表面的中心至像源(例如，用于调 制投影信号的空间光调制器的表面)在光轴上的距离。更具体地，TTL进一步可满足3.25mm≤TTL≤3.51mm。满足条件式3mm＜TTL＜3.7mm，有利于实现投影镜头的小型化，从而有利于该投影镜头更广泛地搭载于各类便携式电子产品。
在示例性实施方式中，本申请的投影镜头可满足条件式0.7＜f2/f＜1.2，其中，f2为第二透镜的有效焦距，f为投影镜头的总有效焦距。更具体地，f2和f进一步可满足0.80≤f2/f≤1.16。合理控制第二透镜的光焦度，有利于平衡镜头的小型化和投影成像质量。
在示例性实施方式中，本申请的投影镜头可满足条件式NA≥0.18，其中，NA为投影镜头的物方数值孔径。更具体地，NA进一步可满足NA＝0.20。投影镜头具有较大的数值孔径，可提高投影能量效率，从而获得更高亮度的投影图像。
在示例性实施方式中，本申请的投影镜头在约800nm至约1000nm的光波波段中，光线透过率大于85％。这样的设置有利于提高近红外光线透过投影镜头的透过率，从而获得更高亮度的近红外投影图像。
在示例性实施方式中，本申请的投影镜头可满足条件式-0.6＜R4/f＜-0.2，其中，R4为第二透镜的成像侧表面的曲率半径，f为投影镜头的总有效焦距。更具体地，R4和f进一步可满足-0.54≤R4/f≤-0.40。合理控制R4和f的比值，有利于减小投影镜头的象散，提升投影成像质量。
在示例性实施方式中，本申请的投影镜头可满足条件式(R2-R1)/(R2+R1)＜0.5，其中，R2为第一透镜的成像侧表面的曲率半径，R1为第一透镜的像源侧表面的曲率半径。更具体地，R2和R1进一步可满足0＜(R2-R1)/(R2+R1)＜0.5，例如，0.13≤(R2-R1)/(R2+R1)≤0.47。满足条件式(R2-R1)/(R2+R1)＜0.5，有利于第一透镜的加工制造；同时，还可以避免由于曲率半径过小而引致的公差敏感度增加。
在示例性实施方式中，本申请的投影镜头可满足条件式1.0＜DT22/DT21＜1.3，其中，DT22为第二透镜的成像侧表面的有效半口径，DT21为第二透镜的像源侧表面的有效半口径。更具体地，DT22和DT21进一步可满足1.05≤DT22/DT21≤1.19。满足条件式1.0＜ DT22/DT21＜1.3，有利于避免由于光线过度弯折而造成的成像质量的下降；同时，还有利于避免公差敏感性较高而引致的不易加工制造等问题。
在示例性实施方式中，上述投影镜头还可包括至少一个光阑，以提升镜头的成像质量。光阑可根据需要设置在任意位置处，例如，光阑可设置在第二透镜与成像侧之间。
可选地，上述投影镜头还可包括其他公知的光学投影元件，例如，棱镜、场镜等。
根据本申请的上述实施方式的投影镜头可采用例如两片透镜，通过合理分配各透镜的光焦度、面型、各透镜的中心厚度以及各透镜之间的轴上间距等，使得投影镜头具有小型化、大数值孔径、低敏感性、高成像品质等至少一个有益效果。
在本申请的实施方式中，各透镜的镜面中的至少一个为非球面镜面。非球面透镜的特点是：从透镜中心到透镜周边，曲率是连续变化的。与从透镜中心到透镜周边具有恒定曲率的球面透镜不同，非球面透镜具有更佳的曲率半径特性，具有改善歪曲像差及改善像散像差的优点。采用非球面透镜后，能够尽可能地消除在成像的时候出现的像差，从而改善成像质量。
然而，本领域的技术人员应当理解，在未背离本申请要求保护的技术方案的情况下，可改变构成投影镜头的透镜数量，来获得本说明书中描述的各个结果和优点。例如，虽然在实施方式中以两片透镜为例进行了描述，但是该投影镜头不限于包括两片透镜。如果需要，该投影镜头还可包括其它数量的透镜。
下面参照附图进一步描述可适用于上述实施方式的投影镜头的具体实施例。
实施例1
以下参照图1至图2B描述根据本申请实施例1的投影镜头。图1示出了根据本申请实施例1的投影镜头的结构示意图。
如图1所示，根据本申请示例性实施方式的投影镜头沿光轴由像 源侧至成像侧依序包括：第一透镜E1、第二透镜E2和光阑STO。
第一透镜E1具有负光焦度，其像源侧表面S1为凹面，成像侧表面S2为凸面。第二透镜E2具有正光焦度，其像源侧表面S3为凹面，成像侧表面S4为凸面。在约800nm至约1000nm光波波段中，该投影镜头的光线透过率大于85％。来自像源的光依序穿过各表面S1至S4并最终成像在例如投影屏幕的成像面上(未示出)。
表1示出了实施例1的投影镜头的各透镜的表面类型、曲率半径、厚度、材料及圆锥系数，其中，曲率半径和厚度的单位均为毫米(mm)。
Figure PCTCN2018087037-appb-000001
表1
由表1可知，第一透镜E1的像源侧表面S1和成像侧表面S2以及第二透镜E2的像源侧表面S3和成像侧表面S4均为非球面。在本实施例中，各非球面透镜的面型x可利用但不限于以下非球面公式进行限定：
Figure PCTCN2018087037-appb-000002
其中，x为非球面沿光轴方向在高度为h的位置时，距非球面顶点的距离矢高；c为非球面的近轴曲率，c＝1/R(即，近轴曲率c为上表1中曲率半径R的倒数)；k为圆锥系数(在表1中已给出)；Ai是非球面第i-th阶的修正系数。下表2给出了可用于实施例1中各非球面镜面S1-S4的高次项系数A 4、A 6、A 8、A 10和A 12。
面号 A4 A6 A8 A10 A12
S1 -3.1511E-01 -4.7845E-01 1.1704E+00 -3.5529E+00 3.1022E+00
S2 -1.9839E-01 2.7878E-02 -1.0343E-01 7.7254E-02 -7.2984E-03
S3 -4.5669E-03 8.2476E-02 -8.0116E-02 5.1704E-02 -1.8540E-02
S4 1.6442E-02 1.4075E-02 2.1974E-02 -1.2275E-02 -7.8684E-04
表2
表3给出实施例1中投影镜头的总有效焦距f、各透镜的有效焦距f1和f2、投影镜头的光学总长度TTL、投影镜头的最大半视场角HFOV以及投影镜头的物方数值孔径NA。
参数 f(mm) f1(mm) f2(mm) TTL(mm) HFOV(°) NA
数值 3.19 -16.01 2.93 3.50 8.9 0.20
表3
实施例1中的投影镜头满足：
f2/f＝0.92，其中，f2为第二透镜E2的有效焦距，f为投影镜头的总有效焦距；
R4/f＝-0.44，其中，R4为第二透镜E2的成像侧表面S4的曲率半径，f为投影镜头的总有效焦距；
(R2-R1)/(R2+R1)＝0.28，其中，R2为第一透镜E1的成像侧表面S2的曲率半径，R1为第一透镜E1的像源侧表面S1的曲率半径；
DT22/DT21＝1.08，其中，DT22为第二透镜E2的成像侧表面S4的有效半口径，DT21为第二透镜E2的像源侧表面S3的有效半口径。
图2A示出了实施例1的投影镜头的畸变曲线，其表示不同视角情况下的畸变大小值。图2B示出了实施例1的投影镜头的倍率色差曲线，其表示光线经由镜头后在成像面上的不同的像高的偏差。根据图2A至图2B可知，实施例1所给出的投影镜头能够实现良好的成像品质。
实施例2
以下参照图3至图4B描述根据本申请实施例2的投影镜头。在本实施例及以下实施例中，为简洁起见，将省略部分与实施例1相似的描述。图3示出了根据本申请实施例2的投影镜头的结构示意图。
如图3所示，根据本申请示例性实施方式的投影镜头沿光轴由像 源侧至成像侧依序包括：第一透镜E1、第二透镜E2和光阑STO。
第一透镜E1具有负光焦度，其像源侧表面S1为凹面，成像侧表面S2为凸面。第二透镜E2具有正光焦度，其像源侧表面S3为凸面，成像侧表面S4为凸面。在约800nm至约1000nm光波波段中，该投影镜头的光线透过率大于85％。来自像源的光依序穿过各表面S1至S4并最终成像在例如投影屏幕的成像面上(未示出)。
表4示出了实施例2的投影镜头的各透镜的表面类型、曲率半径、厚度、材料及圆锥系数，其中，曲率半径和厚度的单位均为毫米(mm)。
Figure PCTCN2018087037-appb-000003
表4
由表4可知，在实施例2中，第一透镜E1的像源侧表面S1和成像侧表面S2以及第二透镜E2的像源侧表面S3和成像侧表面S4均为非球面。表5示出了可用于实施例2中各非球面镜面的高次项系数，其中，各非球面面型可由上述实施例1中给出的公式(1)限定。
面号 A4
S1 0.0000E+00
S2 -2.6235E-03
S3 0.0000E+00
S4 0.0000E+00
表5
表6给出实施例2中各透镜的有效焦距f1和f2、投影镜头的总有效焦距f、投影镜头的光学总长度TTL、投影镜头的最大半视场角HFOV以及投影镜头的物方数值孔径NA。
参数 f(mm) f1(mm) f2(mm) TTL(mm) HFOV(°) NA
数值 2.99 -4.23 2.40 3.50 11.3 0.20
表6
图4A示出了实施例2的投影镜头的畸变曲线，其表示不同视角情况下的畸变大小值。图4B示出了实施例2的投影镜头的倍率色差曲线，其表示光线经由镜头后在成像面上的不同的像高的偏差。根据图4A至图4B可知，实施例2所给出的投影镜头能够实现良好的成像品质。
实施例3
以下参照图5至图6B描述了根据本申请实施例3的投影镜头。图5示出了根据本申请实施例3的投影镜头的结构示意图。
如图5所示，根据本申请示例性实施方式的投影镜头沿光轴由像源侧至成像侧依序包括：第一透镜E1、第二透镜E2和光阑STO。
第一透镜E1具有负光焦度，其像源侧表面S1为凹面，成像侧表面S2为凸面。第二透镜E2具有正光焦度，其像源侧表面S3为凹面，成像侧表面S4为凸面。在约800nm至约1000nm光波波段中，该投影镜头的光线透过率大于85％。来自像源的光依序穿过各表面S1至S4并最终成像在例如投影屏幕的成像面上(未示出)。
表7示出了实施例3的投影镜头的各透镜的表面类型、曲率半径、厚度、材料及圆锥系数，其中，曲率半径和厚度的单位均为毫米(mm)。
Figure PCTCN2018087037-appb-000004
表7
由表7可知，在实施例3中，第一透镜E1的像源侧表面S1和成像侧表面S2以及第二透镜E2的像源侧表面S3和成像侧表面S4均为 非球面。表8示出了可用于实施例3中各非球面镜面的高次项系数，其中，各非球面面型可由上述实施例1中给出的公式(1)限定。
面号 A4 A6
S1 -2.2671E-01 8.6171E-02
S2 -3.5722E-02 7.4530E-02
S3 5.5129E-02 -2.4410E-02
S4 1.4254E-02 4.9197E-03
表8
表9给出实施例3中各透镜的有效焦距f1和f2、投影镜头的总有效焦距f、投影镜头的光学总长度TTL、投影镜头的最大半视场角HFOV以及投影镜头的物方数值孔径NA。
参数 f(mm) f1(mm) f2(mm) TTL(mm) HFOV(°) NA
数值 3.35 -13.03 3.15 3.51 8.5 0.20
表9
图6A示出了实施例3的投影镜头的畸变曲线，其表示不同视角情况下的畸变大小值。图6B示出了实施例3的投影镜头的倍率色差曲线，其表示光线经由镜头后在成像面上的不同的像高的偏差。根据图6A至图6B可知，实施例3所给出的投影镜头能够实现良好的成像品质。
实施例4
以下参照图7至图8B描述了根据本申请实施例4的投影镜头。图7示出了根据本申请实施例4的投影镜头的结构示意图。
如图7所示，根据本申请示例性实施方式的投影镜头沿光轴由像源侧至成像侧依序包括：第一透镜E1、第二透镜E2和光阑STO。
第一透镜E1具有负光焦度，其像源侧表面S1为凹面，成像侧表面S2为凸面。第二透镜E2具有正光焦度，其像源侧表面S3为凹面，成像侧表面S4为凸面。在约800nm至约1000nm光波波段中，该投影镜头的光线透过率大于85％。来自像源的光依序穿过各表面S1至S4并最终成像在例如投影屏幕的成像面上(未示出)。
表10示出了实施例4的投影镜头的各透镜的表面类型、曲率半径、厚度、材料及圆锥系数，其中，曲率半径和厚度的单位均为毫米(mm)。
Figure PCTCN2018087037-appb-000005
表10
由表10可知，在实施例4中，第一透镜E1的像源侧表面S1和成像侧表面S2以及第二透镜E2的像源侧表面S3和成像侧表面S4均为非球面。表11示出了可用于实施例4中各非球面镜面的高次项系数，其中，各非球面面型可由上述实施例1中给出的公式(1)限定。
面号 A4 A6 A8 A10
S1 7.4576E-01 8.2269E-01 -5.6806E-01 -1.4221E-01
S2 3.4599E-01 8.2827E-01 -3.3316E-01 1.1853E+00
S3 9.0238E-02 -1.1208E-01 8.6073E-02 -2.3359E-02
S4 1.0819E-02 -5.1419E-03 3.8858E-04 9.7104E-04
表11
表12给出实施例4中各透镜的有效焦距f1和f2、投影镜头的总有效焦距f、投影镜头的光学总长度TTL、投影镜头的最大半视场角HFOV以及投影镜头的物方数值孔径NA。
参数 f(mm) f1(mm) f2(mm) TTL(mm) HFOV(°) NA
数值 2.65 -22.18 3.08 3.25 10.8 0.20
表12
图8A示出了实施例4的投影镜头的畸变曲线，其表示不同视角情况下的畸变大小值。图8B示出了实施例4的投影镜头的倍率色差曲线，其表示光线经由镜头后在成像面上的不同的像高的偏差。根据图8A至图8B可知，实施例4所给出的投影镜头能够实现良好的成像 品质。
实施例5
以下参照图9至图10B描述了根据本申请实施例5的投影镜头。图9示出了根据本申请实施例5的投影镜头的结构示意图。
如图9所示，根据本申请示例性实施方式的投影镜头沿光轴由像源侧至成像侧依序包括：第一透镜E1、第二透镜E2和光阑STO。
第一透镜E1具有负光焦度，其像源侧表面S1为凹面，成像侧表面S2为凸面。第二透镜E2具有正光焦度，其像源侧表面S3为凹面，成像侧表面S4为凸面。在约800nm至约1000nm光波波段中，该投影镜头的光线透过率大于85％。来自像源的光依序穿过各表面S1至S4并最终成像在例如投影屏幕的成像面上(未示出)。
表13示出了实施例5的投影镜头的各透镜的表面类型、曲率半径、厚度、材料及圆锥系数，其中，曲率半径和厚度的单位均为毫米(mm)。
Figure PCTCN2018087037-appb-000006
表13
由表13可知，在实施例5中，第一透镜E1的像源侧表面S1和成像侧表面S2以及第二透镜E2的像源侧表面S3和成像侧表面S4均为非球面。表14示出了可用于实施例5中各非球面镜面的高次项系数，其中，各非球面面型可由上述实施例1中给出的公式(1)限定。
面号 A4 A6 A8 A10 A12 A14 A16
S1 1.0312E+00 -1.4399E+00 9.9617E+00 -5.1343E+01 1.5539E+02 -2.5274E+02 1.5977E+02
S2 8.2510E-01 -4.9940E-01 9.6016E+00 -5.6121E+01 1.8908E+02 -3.1914E+02 2.0013E+02
S3 4.3806E-02 -5.7311E-02 9.6542E-02 -7.9879E-02 4.1774E-02 -1.2636E-02 1.6612E-03
S4 -1.6735E-02 -1.5435E-02 1.6578E-02 -2.5667E-02 2.2051E-02 -1.0380E-02 2.0921E-03
表14
表15给出实施例5中各透镜的有效焦距f1和f2、投影镜头的总有效焦距f、投影镜头的光学总长度TTL、投影镜头的最大半视场角HFOV以及投影镜头的物方数值孔径NA。
参数 f(mm) f1(mm) f2(mm) TTL(mm) HFOV(°) NA
数值 3.17 -5.79 3.03 3.45 9.1 0.20
表15
图10A示出了实施例5的投影镜头的畸变曲线，其表示不同视角情况下的畸变大小值。图10B示出了实施例5的投影镜头的倍率色差曲线，其表示光线经由镜头后在成像面上的不同的像高的偏差。根据图10A至图10B可知，实施例5所给出的投影镜头能够实现良好的成像品质。
综上，实施例1至实施例5分别满足表16中所示的关系。
Figure PCTCN2018087037-appb-000007
表16
以上描述仅为本申请的较佳实施例以及对所运用技术原理的说明。本领域技术人员应当理解，本申请中所涉及的发明范围，并不限于上述技术特征的特定组合而成的技术方案，同时也应涵盖在不脱离所述发明构思的情况下，由上述技术特征或其等同特征进行任意组合而形成的其它技术方案。例如上述特征与本申请中公开的(但不限于)具有类似功能的技术特征进行互相替换而形成的技术方案。

Claims (17)

  1. 投影镜头，沿光轴由像源侧至成像侧依序包括：第一透镜和第二透镜，其特征在于，
    所述第一透镜具有负光焦度，其像源侧表面为凹面，成像侧表面为凸面；
    所述第二透镜具有正光焦度，其成像侧表面为凸面。
  2. 根据权利要求1所述的投影镜头，其特征在于，所述投影镜头的物方数值孔径NA满足NA≥0.18。
  3. 根据权利要求1所述的投影镜头，其特征在于，所述投影镜头的最大半视场角HFOV满足HFOV＜15°。
  4. 根据权利要求2所述的投影镜头，其特征在于，所述投影镜头的光学总长度TTL满足3mm＜TTL＜3.7mm。
  5. 根据权利要求1所述的投影镜头，其特征在于，在800nm至1000nm的光波波段中，所述投影镜头的光线透过率大于85％。
  6. 根据权利要求1至5中任一项所述的投影镜头，其特征在于，所述第二透镜的有效焦距f2与所述投影镜头的总有效焦距f满足0.7＜f2/f＜1.2。
  7. 根据权利要求1至5中任一项所述的投影镜头，其特征在于，所述第二透镜的成像侧表面的曲率半径R4与所述投影镜头的总有效焦距f满足-0.6＜R4/f＜-0.2。
  8. 根据权利要求1至5中任一项所述的投影镜头，其特征在于，所述第一透镜的成像侧表面的曲率半径R2与所述第一透镜的像源侧 表面的曲率半径R1满足(R2-R1)/(R2+R1)＜0.5。
  9. 根据权利要求1至5中任一项所述的投影镜头，其特征在于，所述第二透镜的成像侧表面的有效半口径DT22与所述第二透镜的像源侧表面的有效半口径DT21满足1.0＜DT22/DT21＜1.3。
  10. 投影镜头，沿光轴由像源侧至成像侧依序包括：第一透镜和第二透镜，其特征在于，
    所述第一透镜具有负光焦度，其像源侧表面为凹面，成像侧表面为凸面；
    所述第二透镜具有正光焦度，其成像侧表面为凸面；
    其中，所述投影镜头的光学总长度TTL满足3mm＜TTL＜3.7mm。
  11. 根据权利要求10所述的投影镜头，其特征在于，所述投影镜头的最大半视场角HFOV满足HFOV＜15°。
  12. 根据权利要求11所述的投影镜头，其特征在于，所述投影镜头的物方数值孔径NA满足NA≥0.18。
  13. 根据权利要求10所述的投影镜头，其特征在于，在800nm至1000nm的光波波段中，所述投影镜头的光线透过率大于85％。
  14. 根据权利要求10至13中任一项所述的投影镜头，其特征在于，所述第一透镜的成像侧表面的曲率半径R2与所述第一透镜的像源侧表面的曲率半径R1满足(R2-R1)/(R2+R1)＜0.5。
  15. 根据权利要求10至13中任一项所述的投影镜头，其特征在于，所述第二透镜的成像侧表面的有效半口径DT22与所述第二透镜的像源侧表面的有效半口径DT21满足1.0＜DT22/DT21＜1.3。
  16. 根据权利要求10至13中任一项所述的投影镜头，其特征在于，所述第二透镜的成像侧表面的曲率半径R4与所述投影镜头的总有效焦距f满足-0.6＜R4/f＜-0.2。
  17. 根据权利要求10至13中任一项所述的投影镜头，其特征在于，所述第二透镜的有效焦距f2与所述投影镜头的总有效焦距f满足0.7＜f2/f＜1.2。
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