A SAM projection lens and projection device

Abstract

This application relates to the field of SAM projection lens technology, and provides a SAM projection lens and projection device. The SAM projection lens includes a rear group, a middle group, and a front group arranged sequentially from the object side to the image side along the optical axis. The optical power distribution of the rear group and the front group is "negative-positive-negative". Each of the rear group, the middle group, and the front group includes a cemented lens. The SAM projection lens and projection device provided in this application have good image quality and high resolution.

Description

Technical Field

[0001] This application belongs to the field of SAM projection lens technology, and particularly relates to a SAM projection lens and projection device. Background Technology

[0002] SAM projection lenses can achieve clear image quality on tilted projection surfaces and are widely used in circuit board defect detection, head-up displays (HUDs), and other fields. However, existing SAM projection lenses achieve imaging by simultaneously tilting the object plane and the projection plane (image plane), requiring the aberrations of the projection plane to meet a certain linear distribution in the image space. This places strict requirements on aberration correction, which is challenging in fields with high resolution requirements. Summary of the Invention

[0003] In view of this, the present application provides a SAM projection lens and projection device, which aims to solve the problem that existing SAM projection lenses have strict requirements for aberration correction and are difficult to correct aberrations in fields with high resolution requirements.

[0004] A first aspect of this application provides a Sham projection lens, including a rear group, a middle group, and a front group arranged sequentially from the object side to the image side along the optical axis.

[0005] The optical power distribution of both the rear group and the front group is "negative-positive-negative";

[0006] The rear group, the middle group, and the front group all include cemented lenses.

[0007] In one embodiment, the rear group includes at least a first cemented lens, a second cemented lens, and three positive power lenses arranged in succession.

[0008] In one embodiment, in the first cemented lens and the second cemented lens, the refractive index difference between the positive power lens and the negative power lens is >0.2 and the Abbe number difference is >30;

[0009] And / or, of the three consecutive positive power lenses, the middle positive power lens is biconvex.

[0010] And / or, the intermediate positive power lens has a refractive index ≤1.65 and an Abbe number ≥60.

[0011] In one embodiment, the rear group includes a first negative power lens, a second negative power lens, a third positive power lens, a fourth positive power lens, a fifth positive power lens, a sixth negative power lens, a seventh positive power lens, and an eighth negative power lens.

[0012] The second negative power lens and the third positive power lens are bonded together to form the first cemented lens;

[0013] The total optical power of the second negative optical power lens, the third positive optical power lens, the fourth positive optical power lens, and the fifth positive optical power lens is positive;

[0014] The three positive power lenses arranged in succession include the third positive power lens, the fourth positive power lens, and the fifth positive power lens;

[0015] The total optical power of the sixth negative optical power lens, the seventh positive optical power lens, and the eighth negative optical power lens is negative;

[0016] The fifth positive power lens, the sixth negative power lens, and the seventh positive power lens are bonded together to form the second cemented lens.

[0017] In one embodiment, during the transmission of the light beam from the object side to the image side, the highest light beam height at the first negative power lens is the first height, the lowest light beam height at the fourth positive power lens is the second height, and the lowest light beam height at the eighth negative power lens is the third height.

[0018] Wherein, the second height is greater than the first height, and the second height is greater than the third height.

[0019] In one embodiment, the middle group includes a third cemented lens;

[0020] The total optical power of the third cemented lens is positive.

[0021] In the third cemented lens, the refractive index difference between the lens near the rear group and the lens near the front group is positive.

[0022] In one embodiment, the refractive index difference ranges from 0.1 to 0.15;

[0023] And / or, the third cemented lens includes a ninth negative power lens and a tenth positive power lens.

[0024] In one embodiment, the front group includes at least two consecutively arranged negative power lenses, as well as a fourth cemented lens and a fifth cemented lens.

[0025] In one embodiment, the two consecutively arranged negative power lenses have a refractive index ≤ 1.65 and an Abbe number ≥ 60;

[0026] And / or, the two consecutively arranged negative power lenses are, in order, biconcave and meniscus.

[0027] In one embodiment, the front group includes an eleventh negative power lens, a twelfth positive power lens, a thirteenth positive power lens, a fourteenth negative power lens, a fifteenth positive power lens, a sixteenth negative power lens, and a seventeenth negative power lens.

[0028] The eleventh negative power lens and the twelfth positive power lens are bonded together to form the fourth cemented lens;

[0029] The total optical power of the twelfth positive optical power lens, the thirteenth positive optical power lens, the fourteenth negative optical power lens, and the fifteenth positive optical power lens is positive;

[0030] The thirteenth positive power lens, the fourteenth negative power lens, and the fifteenth positive power lens are bonded together to form the fifth cemented lens;

[0031] The total optical power of the sixteenth negative optical power lens and the seventeenth negative optical power lens is negative.

[0032] In one embodiment, during the transmission of the light beam from the object side to the image side, the lowest light beam height at the eleventh negative power lens is the fourth height, the highest light beam height at the thirteenth positive power lens is the fifth height, and the lowest light beam height at the seventeenth negative power lens is the sixth height.

[0033] Wherein, the fourth height is less than the sixth height, and the fourth height is less than the fifth height.

[0034] In one embodiment, all lenses in the Sham projection lens are spherical lenses.

[0035] In one embodiment, the Sham projection lens further includes a display chip, a quarter-wave plate, a polarizing beam splitter, and a polarizer arranged sequentially on the object side.

[0036] A second aspect of this application provides a head-up display device, including the Sham projection lens provided in the first aspect.

[0037] In one embodiment, the projection device is a head-up display device or a circuit board defect detection device.

[0038] In the Sham projection lens provided by the first aspect of this application, the optical power distribution of the rear and front groups is "negative-positive-negative", which can realize the high and low differences of local beams, thereby correcting field curvature; the rear, middle and front groups all include cemented lenses to realize distributed correction of chromatic aberration. By splitting the large optical power, higher-order aberrations are reduced, and by combining positive and negative optical power surfaces to achieve positive and negative cancellation, aperture aberrations, including spherical aberration, coma and astigmatism, are corrected, so that the entire lens has small aberrations and good imaging quality, and is suitable for fields with high resolution requirements.

[0039] The projection device provided in the second aspect of the embodiments of this application has good image quality and high resolution by adopting the Sham projection lens provided in the first aspect. Attached Figure Description

[0040] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0041] Figure 1 This is a schematic diagram of the first structure of the Sham projection lens provided in the embodiments of this application;

[0042] Figure 2 This is a schematic diagram of the structure of the rear group provided in the embodiments of this application;

[0043] Figure 3 This is a schematic diagram of the height of light rays propagating in a Sham projection lens provided in an embodiment of this application;

[0044] Figure 4 This is a schematic diagram of the structure of the middle group provided in the embodiments of this application;

[0045] Figure 5 This is a schematic diagram of the front assembly provided in an embodiment of this application;

[0046] Figure 6 This is a schematic diagram of a second structure of the Sham projection lens provided in the embodiments of this application;

[0047] Figure 7 This is a schematic diagram of the Sham projection lens and its projection surface provided in an embodiment of this application;

[0048] Figure 8 This is a schematic diagram of the third structure of the Sham projection lens provided in the embodiments of this application;

[0049] Figure 9 This is a schematic diagram of the modulation transfer function at the display chip provided in the embodiments of this application;

[0050] Icon labels:

[0051] 100 - Projection lens;

[0052] 101 - Display chip;

[0053] 102 - Protective Glass;

[0054] 103-1 / 4 wave plate;

[0055] 104-polarizing beam splitter;

[0056] 105-Polarizer;

[0057] 110 - Rear group, 111 - First negative power lens, 112 - Second negative power lens, 113 - Third positive power lens, 114 - Fourth positive power lens, 115 - Fifth positive power lens, 116 - Sixth negative power lens, 117 - Seventh positive power lens, 118 - Eighth negative power lens;

[0058] 120 - Middle group, 121 - Ninth negative power lens, 122 - Tenth positive power lens, 123 - Aperture stop;

[0059] 130 - Front group, 131 - Eleventh negative power lens, 132 - Twelfth positive power lens, 133 - Thirteenth positive power lens, 134 - Fourteenth negative power lens, 135 - Fifteenth positive power lens, 136 - Sixteenth negative power lens, 137 - Seventeenth negative power lens. Detailed Implementation

[0060] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present application.

[0061] The term "comprising," and any variations thereof, in the specification, claims, and accompanying drawings of this application are intended to cover a non-exclusive inclusion. For example, a process, method, system, product, or apparatus that comprises a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to such processes, methods, products, or apparatus. Furthermore, the terms "first," "second," and "third," etc., are used to distinguish different objects, not to describe a specific order.

[0062] like Figure 1 As shown, this embodiment provides a Sham projection lens 100, which includes a rear group 110, a middle group 120 and a front group 130 arranged sequentially from the object side to the image side along the optical axis.

[0063] The optical power distribution of both the rear group 110 and the front group 130 is "negative-positive-negative";

[0064] The rear group 110, the middle group 120, and the front group 130 all include cemented lenses.

[0065] In application, the rear group 110 and the front group 130 are arranged in a roughly symmetrical "negative-positive-negative" configuration in terms of optical power to achieve local differences in beam height, thereby correcting field curvature. The Sham projection lens 100 requires a small amount of positive and negative cancellation to correct aberrations, aiming to achieve a more consistent image quality in a linearly tilted image space. Therefore, field curvature correction is difficult to achieve through large differences in ray height on the positive and negative optical power surfaces, as this would introduce significant aperture aberrations that are difficult to compensate for using other lens groups. In this embodiment, field curvature correction is primarily achieved through local correction and the introduction of field lenses; local correction refers to breaking down the field curvature into smaller parts and correcting it in different areas of the lens. Since the height difference of rays in the beam cannot be too large, the amount of field curvature correction each time is limited, requiring repeated use of local correction and field lens introduction methods in multiple areas of the Sham projection lens 100.

[0066] In application, the entire Sham projection lens 100 is equipped with multiple cemented lenses distributed throughout the rear group 110, middle group 120, and front group 130 to achieve distributed chromatic aberration correction, thus correcting chromatic aberration at its nascent stage. When aberrations propagate between lenses, they generate advanced derivative aberrations on top of intrinsic aberrations. Generally, the optimal location for aberration correction is near the origin, where primary aberrations are abundant and advanced aberrations are few, making correction easier and less likely to leave residues. In this embodiment, by inserting a cemented lens every few lenses, chromatic aberration can be suppressed to the greatest extent possible across the entire Sham projection lens 100, with virtually no advanced chromatic aberration generated.

[0067] In applications, high-power splitting can reduce higher-order aberrations. By combining positive and negative power surfaces to achieve positive-negative cancellation, aperture aberrations, including spherical aberration, coma, and astigmatism, can be corrected. The Sham projection lens 100, with its symmetrical "negative-positive-negative" power layout, uses a symmetrical structure to reduce transverse aberrations, such as coma. Because the architecture of the Sham projection lens 100 is similar to that of a telephoto lens, it is asymmetrical overall. By constructing a symmetrical power distribution locally and adjusting the lens shape, aberration correction requirements can be met. At lens surfaces with higher light intensity, aperture aberrations are larger. By splitting the lens (using several positive lenses consecutively), the angle of light incidence can be reduced, thereby reducing the generation of higher-order aberrations. At other locations, adjacent positive and negative power surfaces are used to cancel out aberrations, leaving the desired higher-order aberrations, thus achieving aberration balance throughout the Sham projection lens 100.

[0068] like Figure 1 As shown, in one embodiment, the rear group 110 includes at least a first cemented lens, a second cemented lens, and three positive power lenses arranged in succession.

[0069] In application, the "positive" power region of the rear group 110 approximates a symmetrical structure, with cemented lenses on the left and right sides. The materials of the positive and negative power lenses of the cemented lenses need to meet the chromatic aberration correction requirements, thus effectively correcting the chromatic aberration of the system. In terms of power layout, three consecutive positive power lenses are sandwiched between the cemented lenses on both sides. The positive power lenses on the left and right sides can be regarded as either products of positive lens splitting or as part of the cemented lenses. This shared relationship allows a single positive power lens to perform two functions simultaneously, resulting in high utilization and effectively reducing the size and cost of the entire SAM projection lens 100.

[0070] In one embodiment, in the first cemented lens and the second cemented lens, the refractive index difference between the positive power lens and the negative power lens is >0.2 and the Abbe number difference is >30;

[0071] And / or, in a series of three positive power lenses, the middle positive power lens is biconvex;

[0072] And / or, the refractive index of the intermediate positive power lens is ≤1.65 and the Abbe number is ≥60.

[0073] In applications, the three positive power lenses arranged in succession are symmetrically positioned. The positive power lens in the middle is biconvex and is used to bear the maximum optical power. At the same time, this lens is made of a material with low refractive index (≤1.65) and high Abbe number (≥60) to minimize chromatic aberration.

[0074] like Figure 2 As shown, in one embodiment, the rear group 110 includes a first negative power lens 111, a second negative power lens 112, a third positive power lens 113, a fourth positive power lens 114, a fifth positive power lens 115, a sixth negative power lens 116, a seventh positive power lens 117, and an eighth negative power lens 118.

[0075] Among them, the second negative power lens 112 and the third positive power lens 113 are bonded together to form the first cemented lens;

[0076] The total optical power of the second negative optical power lens 112, the third positive optical power lens 113, the fourth positive optical power lens 114, and the fifth positive optical power lens 115 is positive;

[0077] The three positive power lenses arranged in succession include a third positive power lens 113, a fourth positive power lens 114, and a fifth positive power lens 115;

[0078] The total optical power of the sixth negative optical power lens 116, the seventh positive optical power lens 117, and the eighth negative optical power lens 118 is negative;

[0079] The fifth positive power lens 115, the sixth negative power lens 116, and the seventh positive power lens 117 are bonded together to form the second cemented lens.

[0080] In application, the optical power distribution of the rear group 110 is "negative-positive-negative"; the first "negative" optical power is achieved by the first negative optical power lens 111; the "positive" optical power is achieved by the first cemented lens formed by bonding the second negative optical power lens 112 and the third positive optical power lens 113, as well as the fourth positive optical power lens 114 and the fifth positive optical power lens 115; the second "negative" optical power is achieved by the sixth negative optical power lens 116, the seventh positive optical power lens 117, and the eighth negative optical power lens 118. The fifth positive optical power lens 115, the sixth negative optical power lens 116, and the seventh positive optical power lens 117 form a cemented triplet lens, which is the second cemented lens of the system.

[0081] like Figure 2 and Figure 3 As shown, in one embodiment, during the transmission of the light beam from the object side to the image side, the highest light beam height at the first negative power lens 111 is the first height H1, the lowest light beam height at the fourth positive power lens 114 is the second height H2, and the lowest light beam height at the eighth negative power lens 118 is the third height H3.

[0082] Among them, the second height H1 > the first height H2, and the second height H1 > the third height H3.

[0083] In the application, the first negative power lens 111 is located near the object side in the Sham projection lens 100. It acts as a field lens in the Sham projection lens 100 to correct field curvature. Along the direction of light propagation, after passing through the first negative power lens 111, the light begins to rise in height and enters the "positive" power region of the rear group 110. The light height at the fourth positive power lens 114 is the highest, which is the second height (e.g., 12 mm). The light height on both sides of the fourth positive power lens 114 gradually decreases, and finally the lowest light heights are achieved at the first negative power lens 111 (e.g., 9.5 mm) and the eighth negative power lens 118 (e.g., 5 mm), respectively. The high light height on the positive power surface and the low light height on the negative power surface is a clear characteristic of field curvature correction. In this embodiment, the relationship between the first height H2 and the third height H3 is not limited; their heights are determined by the optical design parameters of the lens. For example, the first height H2 > the third height H3.

[0084] like Figure 1 and Figure 4 As shown, in one embodiment, the middle group 120 includes a third cemented lens;

[0085] The total optical power of the third cemented lens is positive.

[0086] In the third cemented lens, the refractive index difference between the lens near the rear group 110 and the lens near the front group 130 is positive.

[0087] In one embodiment, in the third cemented lens, the refractive index difference between the lens near the rear group 110 and the lens near the front group 130 ranges from 0.1 to 0.15.

[0088] In application, the third cemented lens of the middle group 120 is not entirely used for chromatic aberration correction. Instead, it corrects spherical aberration, coma, and astigmatism by controlling the curvature direction of the cemented surface and the difference in refractive index between the materials on both sides of the cemented surface. The difference in refractive index between the two sides of the cemented surface of the third cemented lens can be set according to actual needs, and the setting of the refractive index difference determines the effect of spherical aberration, coma, and astigmatism correction.

[0089] like Figure 4 As shown, in one embodiment, the third cemented lens includes a ninth negative power lens 121 and a tenth positive power lens 122.

[0090] In application, the third cemented lens, composed of the ninth negative power lens 121 and the tenth positive power lens 122, has an overall positive optical power. After the divergent beam propagated from the rear group 110 is received by the middle group 120, the height of the light beam reaches its peak again at the middle group 120.

[0091] like Figure 1 and Figure 4 As shown, in one embodiment, the middle group 120 further includes an aperture stop 123 located between the third cemented lens and the front group 130.

[0092] In application, by setting an aperture stop 123 on the side of the middle group 120 close to the front group 130, the incident angle and luminous flux of the light beam can be limited, stray light can be eliminated, and off-axis aberrations can be corrected.

[0093] like Figure 5 As shown, in one embodiment, the front group 130 includes at least two consecutively arranged negative power lenses, as well as a fourth cemented lens and a fifth cemented lens.

[0094] In application, similar to the rear group 110, the front group 130 also has a "negative-positive-negative" power layout.

[0095] In one embodiment, the two consecutively arranged negative power lenses have a refractive index ≤1.65 and an Abbe number ≥60.

[0096] In application, the two consecutively arranged negative power lenses in the front group 130, by using low refractive index, low dispersion, and high Abbe number materials, can reduce the introduction of chromatic aberration. The two are used consecutively to reduce aberrations through lens splitting.

[0097] In one embodiment, two consecutively arranged negative power lenses are biconcave and meniscus, respectively.

[0098] like Figure 5 As shown, in one embodiment, the front group 130 includes an eleventh negative power lens 131, a twelfth positive power lens 132, a thirteenth positive power lens 133, a fourteenth negative power lens 134, a fifteenth positive power lens 135, a sixteenth negative power lens 136, and a seventeenth negative power lens 137.

[0099] Among them, the eleventh negative power lens 131 and the twelfth positive power lens 132 are bonded together to form the fourth cemented lens;

[0100] The total optical power of the twelfth positive optical power lens 132, the thirteenth positive optical power lens 133, the fourteenth negative optical power lens 134, and the fifteenth positive optical power lens 135 is positive;

[0101] The thirteenth positive power lens 133, the fourteenth negative power lens 134, and the fifteenth positive power lens 135 are bonded together to form the fifth cemented lens;

[0102] The total optical power of the sixteenth negative optical power lens 136 and the seventeenth negative optical power lens 137 is negative.

[0103] In application, the middle group 120, together with the eighth negative power lens 118 and the eleventh negative power lens 131, once again realizes the high and low differences of the local beam to correct the field curvature. Here, aberrations are corrected again by sharing lenses, which has a high utilization rate and can effectively reduce the size and cost of the entire Sham projection lens 100.

[0104] In application, the outer contours of the first cemented lens, the third cemented lens, the fourth cemented lens, and the seventeenth negative power lens 137 in the entire Sham projection lens 100 are all meniscus. The meniscus lens is essentially a combination of positive and negative power surfaces. This combination is distributed throughout the front, middle and rear groups of the entire Sham projection lens 100. It corrects aperture aberrations, including coma and astigmatism, primarily spherical aberration, through positive and negative cancellation.

[0105] In application, the first cemented lens, second cemented lens, third cemented lens, fourth cemented lens, and fifth cemented lens can all be split into a double lens with a suitable air gap, while maintaining the contour shape of each individual lens in the double lens as similar to the corresponding individual lens in the original cemented lens. Each positive power lens can also be split into two positive power lenses with equivalent functions. In the embodiments of this application, the specific configuration of each lens is not limited.

[0106] like Figure 3 and Figure 5 As shown, in one embodiment, during the transmission of the light beam from the object side to the image side, the lowest light beam height at the eleventh negative power lens 131 is the fourth height H4, the highest light beam height at the thirteenth positive power lens 133 is the fifth height H5, and the lowest light beam height at the seventeenth negative power lens 137 is the sixth height H6.

[0107] Among them, the fourth altitude H4 < the sixth altitude H6, and the fourth altitude H4 < the fifth altitude H5.

[0108] In application, the light beam height reaches its lowest values ​​at the eleventh negative power lens 131 and the seventeenth negative power lens 137, which are the fourth height (e.g., 8.5 mm) and the sixth height (e.g., 10 mm), respectively, and reaches its highest value at the thirteenth positive power lens 133, which is the fifth height (e.g., 12 mm), thus achieving the effect of field curvature correction. In this embodiment, the relationship between the sixth height H6 and the fifth height H5 is not limited; their heights are determined by the optical design parameters of the lenses. For example, the sixth height H6 < the fifth height H5.

[0109] like Figure 1 , Figure 2 , Figure 4 or Figure 5 As shown, in one embodiment, all lenses in the Sham projection lens 100 are spherical lenses;

[0110] Arranged sequentially from the object side to the image side along the optical axis, the rear group 110 includes: a first negative power lens 111, a second negative power lens 112, a third positive power lens 113, a fourth positive power lens 114, a fifth positive power lens 115, a sixth negative power lens 116, a seventh positive power lens 117, and an eighth negative power lens 118.

[0111] The middle group 120 includes: a ninth negative power lens 121, a tenth positive power lens 122, and an aperture stop 123;

[0112] The front group 130 includes: an eleventh negative power lens 131, a twelfth positive power lens 132, a thirteenth positive power lens 133, a fourteenth negative power lens 134, a fifteenth positive power lens 135, a sixteenth negative power lens 136, and a seventeenth negative power lens 137.

[0113] like Figure 6 As shown, in one embodiment, the Sham projection lens 100 further includes a display chip 101, a protective glass 102, a quarter-wave plate 103, a polarization beam splitter (PBS) 104, and a polarizer 105, which are located on the object side and arranged in sequence.

[0114] In applications, the display chip 101 and the protective glass 102 can be integrated into a single unit. The display chip can be selected based on Digital Light Processing (DLP), Liquid Crystal on Silicon (LCOS), or Liquid Crystal Display (LCD) technologies, depending on actual needs.

[0115] like Figure 7 or Figure 8 As shown, in one embodiment, the display chip 101 is implemented based on LCOS technology and has a size of 0.62 inches (i.e., image plane size). The tilt angle of the entire projection surface of the Sham projection lens 100 (i.e., the object plane where the display plane of the display chip 101 is located) relative to the vertical plane (i.e., the plane perpendicular to the optical axis) can be set according to actual needs (e.g., 15°), and the aperture F# = 2.4; wherein, Figure 8 and Figure 7 The difference is: Figure 8In the fourth cemented lens of the front group 130, the eleventh negative power lens 131 and the twelfth positive power lens 132 are separately arranged. The types, radii of curvature, thicknesses, and glass materials from the object plane to the image plane in the Sham projection lens 100 are shown in Table 1 below (corresponding to...). Figure 7 ) and Table 2 (corresponding) Figure 8 As shown in the image:

[0116] Table 1

[0117]

[0118]

[0119]

[0120] Table 2

[0121]

[0122]

[0123] like Figure 9 As shown, an exemplary schematic diagram of the modulation transfer function (MTF) at display chip 101 is illustrated; where the MTF observation line pair is 150 lp / mm, the horizontal axis represents the spatial frequency in cycles per millimeter (cycles / mm), and the vertical axis represents the MTF value.

[0124] In applications, MTF represents the overall resolving power of an optical system. The MTF value is used to evaluate the image quality of a lens, ranging from 0 to 1. A higher and straighter vertical axis on the MTF curve indicates better image quality, stronger ability to reproduce realistic images, better overlap of curves across different fields of view, and better consistency of image quality. Figure 9 It can be seen that in the visible light band, when the spatial frequency is 150 lp / mm, the MTF of the entire field of view is ≥0.5, and the imaging quality is good.

[0125] This embodiment also provides a projection device, including the Sham projection lens 100 in any of the above embodiments.

[0126] In applications, the projection device can be a HUD device or a projector used in the field of circuit board defect detection. By using the SAM projection lens 100, the image quality is good and the resolution is high (e.g., 4K resolution). When the projection device is used in the field of HUD device circuit board or defect detection, the display chip 101 in the SAM projection lens 100 can be implemented based on LCOS technology. Since aspherical lenses are not used, the structure of the SAM projection lens 100 is simplified and the cost of the SAM projection lens 100 is reduced.

[0127] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A Sham projection lens, characterized in that, It consists of a total of 17 lenses, arranged sequentially from the object side to the image side along the optical axis to form the rear group, middle group, and front group; The rear group includes a first negative power lens, a second negative power lens, a third positive power lens, a fourth positive power lens, a fifth positive power lens, a sixth negative power lens, a seventh positive power lens, and an eighth negative power lens. The middle group includes a third cemented lens, which includes a ninth negative power lens and a tenth positive power lens. The front group includes an eleventh negative power lens, a twelfth positive power lens, a thirteenth positive power lens, a fourteenth negative power lens, a fifteenth positive power lens, a sixteenth negative power lens, and a seventeenth negative power lens. The second negative power lens and the third positive power lens are bonded together to form a first cemented lens; The total optical power of the second negative optical power lens, the third positive optical power lens, the fourth positive optical power lens, and the fifth positive optical power lens is positive; The three positive power lenses arranged in succession include the third positive power lens, the fourth positive power lens, and the fifth positive power lens; The total optical power of the sixth negative optical power lens, the seventh positive optical power lens, and the eighth negative optical power lens is negative; The fifth positive power lens, the sixth negative power lens, and the seventh positive power lens are bonded together to form a second cemented lens; The total optical power of the third cemented lens is positive; The eleventh negative power lens and the twelfth positive power lens are bonded together to form the fourth cemented lens; The total optical power of the twelfth positive optical power lens, the thirteenth positive optical power lens, the fourteenth negative optical power lens, and the fifteenth positive optical power lens is positive; The thirteenth positive power lens, the fourteenth negative power lens, and the fifteenth positive power lens are bonded together to form the fifth cemented lens; The type, radius of curvature, thickness, and glass material of the object plane to the image plane in the Sham projection lens are shown in Table 1 or Table 2 below: Table 1 Table 2 2. A projection device, characterized in that, Including the Sham projection lens as described in claim 1.

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