Large-target-surface high-pixel projection lens

Abstract

The invention provides a large-target-surface high-pixel projection lens which is provided with a first lens with positive focal power, and the image side surface and the object side surface of the first lens are convex surfaces; the image side surface of the second lens is a convex surface, and the object side surface of the second lens is a concave surface; the object side surface of the third lens is a concave surface; the image side surface and the object side surface of the fourth lens are convex surfaces; the fifth lens has positive focal power, the image side surface is a convex surface, the object side surface is a concave surface, a diaphragm is positioned between the first lens and the second lens, and the third lens and the fourth lens are glued to form a glued lens group; and the central thickness CT2 of the second lens and the half-image height IH of the projection lens satisfy 0.3 < = CT2 / IH < = 0.9. The projection lens can meet large-target-surface, high-pixel and large-view-field-angle display illumination, and also can meet the use requirements of good imaging quality.

Description

Technical Field

[0001] The present invention relates to the technical field of projection optical imaging display, and in particular to a large-target-surface high-pixel projection lens. Background Art

[0002] As the growth of the home projection market slows down, people's entertainment needs are not limited to the home, and outdoor entertainment such as in-car entertainment has emerged. In recent years, smart cars have developed more and more rapidly, the smart car market has grown rapidly, and in-car projection has also ushered in new opportunities. Traditional car lights only have lighting functions, but smart cars need to have pixelated information interaction capabilities. Therefore, smart visual car lights such as MicroLED projection pixelated headlights can achieve the linkage between the lighting display system and the sensor system, thereby realizing the electrification, networking, and intelligence of the car. Therefore, pixelated projection is in an emerging development stage. As an important component, the demand for in-car projection lenses is also growing.

[0003] However, the on-board projection lenses currently used in automotive pixelated headlights have a small chip imaging circular target surface, and the projected pixel frame is not large enough, resulting in limited display pattern effects, a small field of view, and poor clarity of the resulting image, which can easily lead to difficulties in observing the light source projection effect in the initial R&D experimental stage and poor projection effect when applied to the entire vehicle headlights in the later stage. Therefore, how to achieve a large target surface, high pixel, and large field of view display of the on-board projection lens while taking into account good imaging quality has become one of the technical problems that urgently need to be solved. Summary of the invention

[0004] The invention provides a projection lens, which is used to solve the problems of the existing vehicle-mounted projection lens, such as small imaging circular target surface, small projectable pixel frame, small field angle and poor definition of projection imaging.

[0005] To achieve the above object, the present invention adopts the following technical solution: The present invention provides a large-image-surface high-pixel projection lens, comprising: The first lens has positive power, and both the image side and the object side are convex near the optical axis; The second lens has negative power, the image side surface is convex at the near optical axis, and the object side surface is concave at the near optical axis; The third lens has negative optical power and its object side surface is concave near the optical axis; The fourth lens has positive refractive power, and both the image side surface and the object side surface are convex near the optical axis; The fifth lens has positive power, the image side surface is convex near the optical axis, and the object side surface is concave near the optical axis; Among them, the first lens and the second lens are both aspherical lenses, and the aperture of the projection lens is located between the first lens and the second lens; the third lens and the fourth lens form a cemented lens; the projection lens satisfies the relationship: 0.3≤CT2 / IH≤0.9; wherein CT2 is the thickness of the second lens on the optical axis, and IH is the half image height of the projection lens.

[0006] In the projection lens provided by the present invention, the aspheric first lens with positive focal power is matched with the image side and object side which are both convex at the near optical axis, which is conducive to controlling the effective aperture of the first lens and achieving a large aperture and high illumination effect. The aspheric second lens with negative focal power is matched with the image side of the near optical axis as a convex surface and the object side as a concave surface, which is conducive to converging the light with a large field angle from the first lens and increasing the field angle of the projection lens. The third lens with negative focal power and the fourth lens with positive focal power are glued together. The combination of positive and negative focal powers can reduce the aberration of the projection lens and is conducive to achieving high-quality imaging and clear projection. The fifth lens with positive focal power is matched with the image side of the near optical axis as a convex surface and the object side of the concave surface, which is conducive to controlling the size of the projection image circle and achieving a large target surface projection effect. The aperture is set between the first lens L1 and the second lens L2. Reasonable control of the light passing through the aperture aperture is conducive to achieving a large aperture and high illumination effect. By limiting the ratio range of the thickness CT2 of the second lens L2 on the optical axis and the half image height IH of the projection lens, the center thickness of the second lens is controlled, which is conducive to achieving a large target surface projection effect.

[0007] Optionally, the projection lens satisfies the relationship: 0.3≤AT5 / IH≤0.8; wherein AT5 is the distance from the object side of the fifth lens to the imaging surface of the projection lens on the optical axis, and IH is the half image height of the projection lens. Satisfying the above relationship is conducive to increasing the projection distance of the projection side by reasonably controlling the distance between the projection side and the fifth lens.

[0008] Optionally, the projection lens satisfies the relationship: 0.35≤CT1 / FOV≤0.85; wherein CT1 is the thickness of the first lens on the optical axis, and FOV is the full field of view of the projection lens. Satisfying the above relationship is conducive to achieving a large field of view projection effect by reasonably controlling the center thickness of the first lens.

[0009] Optionally, the projection lens satisfies the relationship: 0.2≤|R21-R22| / |R21+R22|≤0.4; wherein R21 is the radius of curvature of the image side of the second lens at the optical axis, and R22 is the radius of curvature of the object side of the second lens at the optical axis. Satisfying the above relationship and reasonably allocating the curvatures of the two surfaces of the second lens is conducive to smooth incident light from the first lens, thereby achieving a larger frame and more pixel projection effect.

[0010] Optionally, the projection lens satisfies the relationship: 0.61≤|R51| / |F|≤0.81; wherein R51 is the radius of curvature of the image side of the fifth lens at the optical axis, and F is the effective focal length of the projection lens. Satisfying the above relationship and reasonably controlling the curvature of the fifth lens is conducive to correcting the incident light of a large target surface and achieving a large target surface projection effect.

[0011] Optionally, the projection lens satisfies the relationship: 0.04≤|F1+F2| / |F4+F5|≤0.12; wherein F1 is the focal length of the first lens, F2 is the focal length of the second lens, F4 is the focal length of the fourth lens, and F5 is the focal length of the fifth lens. Satisfying the above relationship and reasonably allocating the focal lengths of the first, second, fourth, and fifth lenses is beneficial to controlling the overall length of the projection lens.

[0012] Optionally, the projection lens satisfies the relationship: 1.5≤|F2+F3| / |F4|≤4; wherein F2 is the focal length of the second lens, F3 is the focal length of the third lens, and F4 is the focal length of the fourth lens. Satisfying the above relationship and reasonably allocating the negative and positive focal powers of the third and fourth lenses is conducive to reducing the aberration of the projection lens and improving the projection imaging quality.

[0013] Optionally, the first lens and the second lens are both made of plastic, and the third lens, the fourth lens and the fifth lens are all made of glass.

[0014] Beneficial effects of the present invention: The projection lens of the present invention corrects the off-axis field aberration through the first and second aspherical lenses, reduces the on-axis spherical aberration through the positive and negative bonding of the third and fourth lenses, and reasonably controls the size of the target surface through the fifth lens, and the combination together realizes the projection effect of large target surface, large field of view, high pixel and high imaging quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the structure of the projection lens provided in the first embodiment of the present application.

[0016] Figure 2A yes Figure 1 The longitudinal spherical aberration curve of the projection lens is shown.

[0017] Figure 2B yes Figure 1 Astigmatism curve of the projection lens shown.

[0018] Figure 2C yes Figure 1 Distortion curve diagram of the projection lens shown.

[0019] Figure 3 yes Figure 1 Relative illumination diagram of the projection lens shown.

[0020] Figure 4 It is a schematic diagram of the structure of a projection lens provided in the second embodiment of the present application.

[0021] Figure 5A yes Figure 4 The longitudinal spherical aberration curve of the projection lens is shown.

[0022] Figure 5B yes Figure 4 Astigmatism curve of the projection lens shown.

[0023] Figure 5C yes Figure 4 Distortion curve diagram of the projection lens shown.

[0024] Figure 6 yes Figure 4 Relative illumination diagram of the projection lens shown.

[0025] Figure 7 It is a schematic diagram of the structure of a projection lens provided in the third embodiment of the present application.

[0026] Fig. 8A yes Figure 7 The longitudinal spherical aberration curve of the projection lens is shown.

[0027] Figure 8B yes Figure 7 Astigmatism curve of the projection lens shown.

[0028] Figure 8C yes Figure 7 Distortion curve diagram of the projection lens shown.

[0029] Fig. 9 yes Figure 7 Relative illumination diagram of the projection lens shown.

[0030] Fig.10 4 is a schematic diagram of the structure of a projection lens provided in the fourth embodiment of the present application.

[0031] Fig.11A yes Fig.10 The longitudinal spherical aberration curve of the projection lens is shown.

[0032] Fig. 11B yes Fig.10 Astigmatism curve of the projection lens shown.

[0033] Fig. 11C yes Fig.10 Distortion curve diagram of the projection lens shown.

[0034] Fig.12 yes Fig.10 Relative illumination diagram of the projection lens shown. DETAILED DESCRIPTION

[0035] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture. If the specific posture changes, the directional indication will also change accordingly.

[0037] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features limited to "first" and "second" may explicitly or implicitly include at least one of the features. In addition, if "and / or" or "and / or" appears in the full text, its meaning includes three parallel solutions. Taking "A and / or B" as an example, it includes solution A, solution B, or solutions that satisfy both A and B. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0038] The technical solution of the present invention will be further described below in conjunction with embodiments and drawings.

[0039] See also Figure 1 The present invention discloses a large-surface high-pixel projection lens, comprising: a first lens L1, a second lens L2, a third lens L3, a fourth lens L4 and a fifth lens L5, which are arranged in sequence from the image plane to the object plane along the optical axis. The first lens L1 has positive focal power, the second lens L2 has negative focal power, the third lens L3 has negative focal power, the fourth lens L4 has positive focal power, and the fifth lens L5 has positive focal power.

[0040] Further, the image side surface S1 and the object side surface S2 of the first lens L1 are both convex at the near optical axis; the image side surface S3 of the second lens L2 is convex at the near optical axis, and the object side surface S4 is concave at the near optical axis; the object side surface S6 of the third lens L3 is concave at the near optical axis; the image side surface S7 and the object side surface S8 of the fourth lens L4 are both convex at the near optical axis; the image side surface S9 of the fifth lens L5 is convex at the near optical axis, and the object side surface S10 is concave at the near optical axis. The first lens L1 and the second lens L2 are both aspherical lenses, and the aperture of the projection lens is located between the first lens L1 and the second lens L2. The third lens L3 and the fourth lens L4 form a cemented lens. The projection lens satisfies the relationship: 0.3≤CT2 / IH≤0.9; wherein CT2 is the thickness of the second lens L2 on the optical axis, and IH is the half image height of the projection lens.

[0041] By reasonably configuring the surface shape and optical focal length of each lens between the first lens L1 to the fifth lens L5, the refraction of light can be controlled to make it smoothly projected after incident, and at the same time, the convergence and diffusion of light can be reasonably matched, so that the projection lens can realize various pattern projection displays. The first lens L1 and the second lens L2 are designed as aspherical mirrors. The aspherical surface can well correct the high-order aberration of the off-axis field of view, so that the projection lens can achieve a high-pixel projection effect. The aperture is set between the first lens L1 and the second lens L2, and the light passing through the aperture aperture is reasonably controlled, so that the projection lens can achieve a large aperture and high illumination effect. The third lens L3 and the fourth lens L4 form a cemented lens. The bonding of positive and negative optical focal lengths is conducive to reducing the spherical aberration on the axis, so that the imaging quality of the projection lens is improved. By limiting the ratio range of the thickness CT2 of the second lens L2 on the optical axis and the half-image height IH of the projection lens, the center thickness of the second lens is controlled, which is conducive to achieving a large target surface projection effect.

[0042] In some embodiments, the projection lens satisfies the relationship: 0.3≤AT5 / IH≤0.8; wherein AT5 is the distance on the optical axis from the object side surface S10 of the fifth lens L5 to the imaging surface S11 of the projection lens, and IH is the half image height of the projection lens. By limiting the ratio range of the distance AT5 on the optical axis from the object side surface S10 of the fifth lens L5 to the imaging surface S11 of the projection lens and the half image height IH of the projection lens, the distance between the projection side and the fifth lens L5 is controlled, which is conducive to increasing the projection distance of the projection side.

[0043] In some embodiments, the projection lens satisfies the relationship: 0.35≤CT1 / FOV≤0.85; wherein CT1 is the thickness of the first lens L1 on the optical axis, and FOV is the full field of view of the projection lens. By limiting the ratio range of the thickness CT1 of the first lens L1 on the optical axis and the full field of view FOV of the projection lens, controlling the center thickness of the first lens L1 is conducive to achieving a large field of view projection effect.

[0044] In some embodiments, the projection lens satisfies the relationship: 0.2≤|R21-R22| / |R21+R22|≤0.4; wherein R21 is the radius of curvature of the image side surface S3 of the second lens L2 at the optical axis, and R22 is the radius of curvature of the object side surface S4 of the second lens L2 at the optical axis. By reasonably allocating the radius of curvature of the image side surface S3 and the object side surface S4 of the second lens L2 at the optical axis, it is beneficial to converge the light of the first lens L1 to smoothly enter, and achieve a larger frame and high-pixel projection effect.

[0045] In some embodiments, the projection lens satisfies the relationship: 0.61≤|R51| / |F|≤0.81; wherein R51 is the radius of curvature of the image side surface S9 of the fifth lens L5 at the optical axis, and F is the effective focal length of the projection lens. By limiting the absolute value of the radius of curvature of the image side surface S9 of the fifth lens L5 at the optical axis and the effective focal length F of the projection lens, the curvature of the image side surface S9 of the fifth lens L5 at the optical axis is controlled, which is beneficial to correct the incident light of a large target surface and achieve a large target surface projection effect.

[0046] In some embodiments, the projection lens satisfies the relationship: 0.04≤|F1+F2| / |F4+F5|≤0.12; wherein F1 is the focal length of the first lens L1, F2 is the focal length of the second lens L2, F4 is the focal length of the fourth lens L4, and F5 is the focal length of the fifth lens L5. By reasonably allocating the focal lengths of the first lens L1, the second lens L2, the fourth lens L4, and the fifth lens L5, it is helpful to control the overall length of the projection lens.

[0047] In some embodiments, the projection lens satisfies the relationship: 1.5≤|F2+F3| / |F4|≤4; wherein F2 is the focal length of the second lens L2, F3 is the focal length of the third lens L3, and F4 is the focal length of the fourth lens L4. Reasonable allocation of the negative focal power of the second lens L2, the negative focal power of the third lens L3, and the positive focal power of the fourth lens L4 is conducive to reducing the aberration of the projection lens and improving the projection imaging quality.

[0048] In some embodiments, the first lens L1 and the second lens L2 are made of plastic, and the third lens L3, the fourth lens L4 and the fifth lens L5 are made of glass. Plastic aspheric lenses are conducive to correcting high-order aberrations in the off-axis field of view, so that pixels in a large off-axis field of view can also be projected clearly, achieving a high-pixel effect, and the cost of plastic lenses is also relatively low. The heat generation near the light source is more serious and the temperature is higher. The high temperature resistance of the glass lens can improve the high temperature resistance reliability of the projection lens.

[0049] The projection lens of the present application will be described in detail below with reference to specific parameters. First embodiment

[0050] In this embodiment, a projection lens is provided, such as Figure 1-3 As shown, the projection lens includes, from the image side to the object side along the optical axis, a first lens L1 with positive optical power, a second lens L2 with negative optical power, a third lens L3 with negative optical power, a fourth lens L4 with positive optical power, and a fifth lens L5 with positive optical power. Among them, the image side surface S1 of the first lens L1 is convex at the near optical axis, the object side surface S2 of the first lens L1 is convex at the near optical axis, the image side surface S3 of the second lens L2 is convex at the near optical axis, the object side surface S4 of the second lens L2 is concave at the near optical axis, the image side surface S5 of the third lens L3 is concave at the near optical axis, the object side surface S6 of the third lens L3 is concave at the near optical axis, the image side surface S7 of the fourth lens L4 is convex at the near optical axis, the object side surface S8 of the fourth lens L4 is convex at the near optical axis, the image side surface S9 of the fifth lens L5 is convex at the near optical axis, and the object side surface S10 of the fifth lens L5 is concave at the near optical axis. The third lens L3 and the fourth lens L4 are cemented to each other to form a cemented lens. The aperture of the projection lens is an aperture aperture, and the aperture aperture is located between the first lens L1 and the second lens L2. The first lens and the second lens are both made of plastic, that is, the first lens L1 and the second lens L2 are both plastic lenses; the third lens, the fourth lens and the fifth lens are all made of glass, that is, the third lens L3, the fourth lens L4 and the fifth lens L5 are all glass lenses. Therefore, by reasonably matching the plastic aspheric lens with good off-axis aberration correction effect and the high-temperature resistant glass lens, it is possible to achieve high-pixel and high-definition projection and perform in-vehicle projection entertainment safely and reliably.

[0051] Table 1 below shows the optical parameters of the projection lens and components in the projection lens provided in this embodiment.

[0052] Among them, f is the effective focal length of the projection lens, FNO is the aperture number of the projection lens, and FOV is the maximum field of view of the projection lens. The components from the projection imaging side of the projection lens to the object side of the projection light source are arranged in order from top to bottom according to Table 1. The STO aperture represents the aperture aperture, and the Y radius is the radius of curvature of the corresponding surface of the lens at the optical axis. The first value of the lens in the "Thickness" parameter column is the thickness of the lens on the optical axis, and the second value is the distance from the object side of the lens to the next optical element on the optical axis. The units of the values ​​of the Y radius, thickness, and focal length (effective focal length) in the table are all millimeters (mm).

[0053] Table 1

[0054] Table 2 below shows the high-order coefficients A4, A6, A8, A10, and A12 of the aspherical surface.

[0055] In this embodiment, the image-side surface and the object-side surface of the first lens L1 and the second lens L2 are both aspherical surfaces, wherein the aspherical lens can satisfy: Among them, Z is the vector height of the aspherical surface, r is the radial coordinate of the aspherical surface, c is the vertex spherical curvature of the aspherical surface, K is the quadratic surface coefficient, A, B, C, D, E, and F are the second-order, fourth-order, sixth-order, eighth-order, tenth-order, and twelfth-order surface coefficients respectively.

[0056] Table 2

[0057] Reference Figure 2A , shows the longitudinal spherical aberration curve of the projection lens provided in this embodiment at wavelengths of 656.27nm, 587.56nm, and 486.13nm. The abscissa represents the focus offset in mm, and the ordinate represents the normalized field of view. It can be seen that the spherical aberration value of the projection lens in this embodiment is better, indicating that the imaging quality of the projection lens in this embodiment is better.

[0058] Reference Figure 2B , shows the astigmatism diagram of the projection lens provided in this embodiment at a wavelength of 587.56nm. The horizontal axis represents the focus offset in mm, and the vertical axis represents the image height in mm. The astigmatism curve represents the curvature T of the meridian imaging surface and the curvature S of the sagittal imaging surface. It can be seen that the astigmatism of the projection lens in this embodiment is well compensated.

[0059] Reference Figure 2C , shows the distortion curve of the projection lens provided in this embodiment at a wavelength of 587.56nm. The horizontal axis represents the distortion, in %, and the vertical axis represents the image height, in mm. It can be seen that at a wavelength of 587.56nm, the distortion of the projection lens in this embodiment is well corrected. Figure 2A-2C It can be seen from the three figures that the projection lens in this embodiment has small aberration, good imaging quality and excellent imaging quality.

[0060] Figure 3 The relative illumination curve of the projection lens provided in this embodiment is shown, which indicates the relative illumination values ​​corresponding to different half-image heights on the imaging plane, with the horizontal axis indicating the half-image height (unit: mm) and the vertical axis indicating the relative illumination value (unit: %). It can be seen from the figure that the relative illumination value of the optical lens is still greater than 86% at the maximum half-image height, indicating that the relative illumination of the optical lens is high and no edge vignetting will be formed. Second embodiment

[0061] In this embodiment, reference Figure 4-6The projection lens of this embodiment includes, from the image side to the object side along the optical axis, a first lens L1 with positive focal power, a second lens L2 with negative focal power, a third lens L3 with negative focal power, a fourth lens L4 with positive focal power, and a fifth lens L5 with positive focal power. Among them, the image side surface S1 of the first lens L1 is convex at the near optical axis, the object side surface S2 of the first lens L1 is convex at the near optical axis, the image side surface S3 of the second lens L2 is convex at the near optical axis, the object side surface S4 of the second lens L2 is concave at the near optical axis, the image side surface S5 of the third lens L3 is convex at the near optical axis, the object side surface S6 of the third lens L3 is concave at the near optical axis, the image side surface S7 of the fourth lens L4 is convex at the near optical axis, the object side surface S8 of the fourth lens L4 is convex at the near optical axis, the image side surface S9 of the fifth lens L5 is convex at the near optical axis, and the object side surface S10 of the fifth lens L5 is concave at the near optical axis. The third lens L3 and the fourth lens L4 are cemented to each other to form a cemented lens. The aperture of the projection lens is an aperture aperture, and the aperture aperture is located between the first lens L1 and the second lens L2.

[0062] The lens parameters of the projection lens in this embodiment are shown in Table 3 and Table 4, wherein the definitions of the names and parameters of the components can be obtained from the first embodiment and are not described in detail here.

[0063] Table 3:

[0064] Table 4:

[0065] In addition, by Figures 5A-5C It can be seen that the projection lens in this embodiment has small aberration, good imaging quality and excellent imaging quality.

[0066] Figure 6 This indicates that the relative illumination of the projection lens in this embodiment is high. Third embodiment

[0067] In the third specific embodiment of the present application, refer to Figure 7-9The projection lens of the third embodiment includes, from the image side to the object side along the optical axis, a first lens L1 with positive focal power, a second lens L2 with negative focal power, a third lens L3 with negative focal power, a fourth lens L4 with positive focal power, and a fifth lens L5 with positive focal power. Among them, the image side surface S1 of the first lens L1 is convex at the near optical axis, the object side surface S2 of the first lens L1 is convex at the near optical axis, the image side surface S3 of the second lens L2 is convex at the near optical axis, the object side surface S4 of the second lens L2 is concave at the near optical axis, the image side surface S5 of the third lens L3 is concave at the near optical axis, the object side surface S6 of the third lens L3 is concave at the near optical axis, the image side surface S7 of the fourth lens L4 is convex at the near optical axis, the object side surface S8 of the fourth lens L4 is convex at the near optical axis, the image side surface S9 of the fifth lens L5 is convex at the near optical axis, and the object side surface S10 of the fifth lens L5 is concave at the near optical axis. The third lens L3 and the fourth lens L4 are cemented to each other to form a cemented lens. The aperture of the projection lens is an aperture aperture, and the aperture aperture is located between the first lens L1 and the second lens L2.

[0068] The lens parameters of the projection lens in the third embodiment are given in Table 5 and Table 6, wherein the definitions of the component names and parameters can be obtained from the first embodiment and are not described in detail here.

[0069] Table 5:

[0070] Table 6:

[0071] In addition, it can be seen from FIG. 8 that the projection lens in this embodiment has a smaller aberration, a better imaging quality, and an excellent imaging quality.

[0072] Fig. 9 This indicates that the relative illumination of the optical lens is high. Fourth embodiment

[0073] In the fourth specific embodiment of the present application, refer to Figure 10-12The projection lens of the fourth embodiment includes, from the image side to the object side along the optical axis, a first lens L1 with positive focal power, a second lens L2 with negative focal power, a third lens L3 with negative focal power, a fourth lens L4 with positive focal power, and a fifth lens L5 with positive focal power. Among them, the image side surface S1 of the first lens L1 is convex at the near optical axis, the object side surface S2 of the first lens L1 is convex at the near optical axis, the image side surface S3 of the second lens L2 is convex at the near optical axis, the object side surface S4 of the second lens L2 is concave at the near optical axis, the image side surface S5 of the third lens L3 is concave at the near optical axis, the object side surface S6 of the third lens L3 is concave at the near optical axis, the image side surface S7 of the fourth lens L4 is convex at the near optical axis, the object side surface S8 of the fourth lens L4 is convex at the near optical axis, the image side surface S9 of the fifth lens L5 is convex at the near optical axis, and the object side surface S10 of the fifth lens L5 is concave at the near optical axis. The third lens L3 and the fourth lens L4 are cemented to each other to form a cemented lens. The aperture of the projection lens is an aperture aperture, and the aperture aperture is located between the first lens L1 and the second lens L2.

[0074] The lens parameters of the projection lens in the fourth embodiment are given in Table 7 and Table 8, wherein the definitions of the component names and parameters can be obtained from the first embodiment and are not described in detail here.

[0075] Table 7:

[0076] Table 8:

[0077] In addition, it can be seen from FIG. 11 that the projection lens in this embodiment has a smaller aberration, a better imaging quality, and an excellent imaging quality. Fig.12 This indicates that the relative illumination of the optical lens is high.

[0078] Please also refer to Table 9, which shows the values ​​of CT2 / IH, AT5 / IH, CT1 / FOV, |R21-R22| / |R21+R22|, |R51 / F|, |F1+F2| / |F4+F5|, and |F2+F3| / F4 in the first to fourth embodiments of the present invention.

[0079] Table 9:

[0080] It can be seen from Table 9 that the projection lenses in the first to fourth embodiments all meet the following conditions: 0.3≤CT2 / IH≤0.9, 0.3≤AT5 / IH≤0.8, 0.35≤CT1 / FOV≤0.85, 0.2≤|R21-R22| / |R21+R22|≤0.4, 0.61≤|R51| / |F|≤0.81, 0.04≤|F1+F2| / |F4+F5|≤0.12, 1.5≤|F2+F3| / |F4|≤4.

Claims

1. A large-image-area high-pixel projection lens, characterized in that: Including the following arranged along the optical axis from the image plane to the object plane: The first lens has positive power, and both the image side and the object side are convex near the optical axis; The second lens has negative power, the image side surface is convex at the near optical axis, and the object side surface is concave at the near optical axis; The third lens has negative optical power and its object side surface is concave near the optical axis; The fourth lens has positive refractive power, and both the image side surface and the object side surface are convex near the optical axis; The fifth lens has positive power, the image side surface is convex near the optical axis, and the object side surface is concave near the optical axis; Among them, the first lens and the second lens are both aspherical lenses, and the aperture of the projection lens is located between the first lens and the second lens; the third lens and the fourth lens form a cemented lens; the projection lens satisfies the relationship: 0.3≤CT2 / IH≤0.9; wherein CT2 is the thickness of the second lens on the optical axis, and IH is the half image height of the projection lens.

2. The large-image-area high-pixel projection lens according to claim 1, characterized in that: The projection lens satisfies the relationship: 0.3≤AT5 / IH≤0.8; Wherein, AT5 is the distance from the object side surface of the fifth lens to the imaging surface of the projection lens on the optical axis, and IH is the half image height of the projection lens.

3. The large-image-area high-pixel projection lens according to claim 1, characterized in that: The projection lens satisfies the relationship: 0.35≤CT1 / FOV≤0.85; Wherein, CT1 is the thickness of the first lens on the optical axis, and FOV is the full field of view of the projection lens.

4. The large-image-area high-pixel projection lens according to claim 1, characterized in that: The projection lens satisfies the relationship: 0.2≤|R21-R22| / |R21+R22|≤0.4; Wherein, R21 is the curvature radius of the image side surface of the second lens at the optical axis, and R22 is the curvature radius of the object side surface of the second lens at the optical axis.

5. The large-image-area high-pixel projection lens according to claim 1, characterized in that: The projection lens satisfies the relationship: 0.61≤|R51| / |F|≤0.81; Wherein, R51 is the radius of curvature of the image side surface of the fifth lens at the optical axis, and F is the effective focal length of the projection lens.

6. The large-image-area high-pixel projection lens according to claim 1, characterized in that: The projection lens satisfies the relationship: 0.04≤|F1+F2| / |F4+F5|≤0.12; Wherein, F1 is the focal length of the first lens, F2 is the focal length of the second lens, F4 is the focal length of the fourth lens, and F5 is the focal length of the fifth lens.

7. The large-image-area high-pixel projection lens according to claim 1, characterized in that: The projection lens satisfies the relationship: 1.5≤|F2+F3| / |F4|≤4; Among them, F2 is the focal length of the second lens, F3 is the focal length of the third lens, and F4 is the focal length of the fourth lens.

8. The large-image-area high-pixel projection lens according to claim 1, characterized in that: The first lens and the second lens are both made of plastic, and the third lens, the fourth lens and the fifth lens are all made of glass.

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