A high-definition projection lens

Abstract

The application belongs to the technical field of optical imaging display, and proposes a high-definition projection lens, which comprises, in sequence from an object side to an image side, a negative-power front lens group, a diaphragm, a positive-power middle focusing group, and a positive-power rear lens group; the lens material adopts a full-glass lens design, which can not only achieve a high-definition picture, but also has small chromatic aberration and low distortion.

Description

Technical Field

[0001] This invention belongs to the field of optical imaging and display technology, and specifically relates to a high-definition projection lens. Background Technology

[0002] In today's fast-paced, efficiency-driven offices, projectors are ubiquitous as a new type of office equipment. Currently, projection display technologies primarily utilize LCOS (Liquid Crystal on Silicon) and DLP (Digital Light Processing) technologies. LCOS technology, with its high resolution and high brightness, meets the modern trend of higher display demands. As chip technology continues to improve, pixel sizes are constantly decreasing, from the original 7-8μm to the current 4μm, requiring higher-resolution projection lenses to achieve high-definition effects. This invention provides a high-definition projection lens that meets the requirements of high-definition chips. Summary of the Invention

[0003] To improve the image quality of projectors, this invention provides a high-definition projection lens. The lens material adopts an all-glass lens design, which not only achieves high-definition images, but also has small chromatic aberration and low distortion.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: a high-definition projection lens, comprising, from the object side to the image side, a front lens group with negative optical power, an aperture stop, a central focusing group with positive optical power, and a rear lens group with positive optical power.

[0005] The negative power front lens group includes a cemented doublet consisting of a first lens with negative power and a second lens with positive power, a third lens with negative power, a fourth lens with negative power, a fifth lens with negative power and a sixth lens with positive power, and a seventh lens with positive power.

[0006] The positive optical power central focusing group is composed of a positive optical power eighth lens;

[0007] The positive optical power rear lens group consists of a triplet lens composed of a negative optical power ninth lens, a positive optical power tenth lens, and a negative optical power eleventh lens, and a positive optical power twelfth lens.

[0008] The aperture stop is located between the front lens group with negative optical power and the middle focusing group with positive optical power.

[0009] Furthermore, the high-definition projection lens has an F / # of 2.2, an FOV of 31°, and a TOTR of 183mm;

[0010] Furthermore, the focal length of the high-definition projection lens is defined as f', the back focal length as lf', the image height of the optical module is defined as 2y', the focal length of the negative power front lens group is defined as f'1, the focal length of the positive power central focusing group is defined as f'2, and the focal length of the positive power rear lens group is defined as f'3.

[0011] The focal length f' and the back focal length lf' satisfy the relationship: |lf' / f'|>1;

[0012] The image height 2y' of the optical module and the focal length f' of the lens satisfy the following relationship: |2y' / f'| > 0.5;

[0013] The focal length f'1 of the negative power front lens group and the focal length f' of the lens satisfy the following relationship: 1 < |f'1 / f'| < 2;

[0014] The focal length f'2 of the focusing group in the positive focal length setting satisfies the relationship f' of the lens: |f'2 / f'| > 8;

[0015] The focal length f'3 of the rear lens group with positive optical power satisfies the relationship f' of the lens: 3<|f'3 / f'|<4;

[0016] Furthermore, all the lenses are made of glass spherical lenses. Specifically, the first, second, fourth, sixth, seventh, eighth, and ninth lenses are made of heavy flint glass, with the first, fourth, and eighth lenses having a refractive index greater than 1.9; the third and eleventh lenses are made of heavy lanthanum flint glass with a refractive index greater than 1.84; the fifth lens is made of heavy phosphorus crown glass with a refractive index between 1.5 and 1.6; the tenth lens is made of fluorine crown glass with a refractive index less than 1.5; and the twelfth lens is made of heavy crown glass with a refractive index between 1.6 and 1.7.

[0017] Furthermore, the first lens, second lens, third lens, fourth lens, sixth lens, seventh lens, eighth lens, ninth lens, and eleventh lens adopt a meniscus structure, the fifth lens adopts a double concave structure, and the tenth lens and twelfth lens adopt a double convex structure.

[0018] Furthermore, the parameters of each lens in this invention are shown in the following table:

[0019]

[0020] The beneficial effects of this invention are as follows: Through the technical solution adopted by the lens described above, the entire image plane is clear, with minimal chromatic aberration and low distortion without sacrificing image quality. 1) Excellent imaging effect: the MTF curve at 125 lp / mm can be maintained at approximately 60% across all fields of view. 2) The entire chromatic aberration is within the Airy disk, with a transverse chromatic aberration <1.35 μm and distortion below 0.7%. 3) The triplet lens composed of the negative power ninth lens, the positive power tenth lens, and the negative power eleventh lens uses heavy flint glass with a refractive index between 1.8 and 1.9, fluorine crown glass with a refractive index between 1.45 and 1.5, and heavy lanthanum flint glass with a refractive index between 1.8 and 1.9, respectively. This triplet lens is beneficial for correcting the image quality degradation caused by temperature changes within a temperature range of -40℃ to 85℃, maintaining image quality stability, and achieving a heat-free design effect. It uses global surface environmentally friendly glass lenses, which have high thermal stability, are easy to process and simple to assemble. It can work stably for a long time in a temperature environment of -40℃ to 85℃ without defocusing, making it very suitable for projection systems in various places. Attached Figure Description

[0021] The structure and features of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0022] Figure 1 This is a schematic diagram of the optical system of the present invention;

[0023] Figure 2 This is a schematic diagram of the MTF (modulation transfer function) according to an embodiment of the present invention;

[0024] Figure 3 This is a schematic diagram of a dot matrix representation of an embodiment of the present invention;

[0025] Figure 4 This is a schematic diagram of color difference in an embodiment of the present invention;

[0026] Figure 5 This is a distortion diagram of an embodiment of the present invention. Detailed Implementation

[0027] See appendix Figure 1-5 This is an embodiment of the present invention, which discloses a high-definition projection lens, comprising, from the object side to the image side, a front lens group with negative optical power S01, an aperture stop STOP, a central focusing group with positive optical power S02, and a rear lens group with positive optical power S03.

[0028] The negative power front lens group S01 includes a cemented doublet consisting of a first lens G1 with negative power and a second lens G2 with positive power, a third lens G3 with negative power, a fourth lens G4 with negative power, a fifth lens G5 with negative power and a sixth lens G6 with positive power, and a seventh lens G7 with positive power. In this embodiment, the first lens G1, the second lens G2, the third lens G3, and the fourth lens G4 adopt a meniscus structure, the fifth lens G5 adopts a biconcave structure, and the sixth lens G6 and the seventh lens G7 adopt a meniscus structure.

[0029] The positive optical power central focusing group S02 is composed of a positive optical power eighth lens G8; in this embodiment, the eighth lens G8 adopts a meniscus structure.

[0030] The positive power rear lens group S03 comprises a cemented triplet lens consisting of a negative power ninth lens G9, a positive power tenth lens G10, and a negative power eleventh lens G11, and a positive power twelfth lens G12. In this embodiment, the ninth lens G9 adopts a meniscus structure, the tenth lens G10 adopts a biconvex structure, the eleventh lens G11 adopts a meniscus structure, and the twelfth lens G12 adopts a biconvex structure.

[0031] The aperture stop (STOP) is located between the negative optical power front lens group (S01) and the positive optical power central focusing group (S02). In this embodiment of the invention, high resolution is achieved while lower cost without using an aspherical lens.

[0032] The focal length of the high-definition projection lens is defined as f', the back focal length as lf', the image height of the optical module as 2y', the focal length of the negative power front lens group S01 is defined as f'1, the focal length of the positive power central focusing group S02 is defined as f'2, and the focal length of the positive power rear lens group S03 is defined as f'3.

[0033] The image height 2y' of the optical module and the focal length f' of the lens satisfy the relationship: |2y' / f'|>0.5; the image height ratio design can enhance the compatibility of the lens, match it with image sensors of different sizes, enable the optical imaging lens to have an image height corresponding to the corresponding chip, and play a positive role in improving the quality of light imaging.

[0034] The focal length f'1 of the negative power front lens group S01 and the focal length f' of the lens satisfy the relationship: 1<|f'1 / f'|<2; which makes off-axis rays smoothly converge to the vicinity of the optical axis, has a good effect on distortion correction and chromatic aberration control, and plays a positive role in improving edge image quality.

[0035] The focal length f'2 of the central focusing group S02 and the focal length f' of the lens satisfy the relationship: |f'2 / f'|>8; by reasonably setting the central lens group, the projection distance can be switched between near and far under limited space conditions, and the total length of the lens can be better limited.

[0036] The focal length f'3 of the rear lens group S03 with positive optical power satisfies the relationship f' of the lens: 3 < |f'3 / f'| < 4; such setting and combination can effectively control distortion and reduce tolerance sensitivity, which is beneficial to the high image quality imaging of this fixed focal length lens.

[0037] The first lens G1, the second lens G2, the fourth lens G4, the sixth lens G6, the seventh lens G7, the eighth lens G8, and the ninth lens G9 are made of heavy flint glass, wherein the first lens G1, the fourth lens G4, and the eighth lens G8 have a refractive index greater than 1.9; the third lens G3 and the eleventh lens G11 are made of heavy lanthanum flint glass with a refractive index greater than 1.84; the fifth lens G5 is made of heavy phosphorus crown glass with a refractive index between 1.5 and 1.6; the tenth lens G10 is made of fluorine crown glass with a refractive index less than 1.5; and the twelfth lens G12 is made of heavy crown glass with a refractive index between 1.6 and 1.7. Through the reasonable selection and combination of lens materials, the system can still maintain good resolution at high temperatures of 85℃ and low temperatures of -40℃, and there is no defocusing at high and low temperatures.

[0038] The cemented doublet consisting of a negative optical power first lens G1 and a positive optical power second lens G2 is designed with a combination of heavy flint glass with a refractive index between 1.8 and 1.9 and heavy flint glass with a refractive index between 1.7 and 1.8, respectively, which can converge the incident light of the optical system and control the system optical path; the cemented doublet consisting of a negative optical power fifth lens G5 and a positive optical power sixth lens G6 is designed with a combination of heavy phosphorus crown glass and heavy flint glass, respectively, to reduce the aperture of the incident light. This allows light to enter and exit smoothly, reducing aberrations and maintaining stable image quality. The cemented lens consisting of the negative power ninth lens G9, the positive power tenth lens G10, and the negative power eleventh lens G11 is made of heavy flint glass with a refractive index between 1.8 and 1.9, fluorine crown glass with a refractive index between 1.45 and 1.5, and heavy lanthanum flint glass with a refractive index between 1.8 and 1.9, respectively. The arrangement of this cemented lens and the selection of materials can correct chromatic aberration, balance imaging aberrations, and improve imaging performance.

[0039] In summary, this invention employs a three-group architecture with optical power of "negative-positive-positive", comprising a total of twelve lenses. By rationally setting, matching, and combining each lens with the optical power, surface shape, and form described above, the aberrations and chromatic aberrations of the projection lens optical imaging system can be reduced, optical sensitivity can be decreased, and the imaging quality of the projection lens can be further improved.

[0040] The optical performance of the projection lens provided in this invention will be described in detail below with reference to specific design parameters. Specific embodiments are as follows:

[0041]

[0042]

[0043] In this embodiment, the distance between the vertex of the rear surface of the second lens G2 and the vertex of the front surface of the third lens G3 is 0.3 mm; the distance between the vertex of the rear surface of the third lens G3 and the vertex of the front surface of the fourth lens G4 is 4.8 mm; the distance between the vertex of the rear surface of the fourth lens G4 and the vertex of the front surface of the fifth lens G5 is 4.66 mm; the distance between the vertex of the rear surface of the sixth lens G6 and the vertex of the front surface of the seventh lens G7 is 15.36 mm; the distance between the vertex of the rear surface of the seventh lens G7 and the stop is 41.37 mm; the distance between the stop and the vertex of the front surface of the eighth lens G8 is 8.44 mm; the distance between the vertex of the front surface of the eighth lens G8 and the vertex of the front surface of the ninth lens G9 is 20.71 mm; and the distance between the vertex of the rear surface of the eleventh lens G11 and the vertex of the front surface of the twelfth lens G12 is 0.2 mm.

[0044] The above embodiments achieve the following technical indicators:

[0045] Focal length: 10.7mm;

[0046] F-number: 2.2;

[0047] Projection ratio: 1.3;

[0048] Projection distance: 1100mm;

[0049] Bias: 0–100%;

[0050] Overall optical length: 183mm;

[0051] Working environment: It can work stably for a long time in the range of -40℃ to 80℃ without defocusing.

[0052] Figure 1 This is a schematic diagram of the optical system structure according to an embodiment of the present invention. The entire structure is small and compact.

[0053] Figure 2The figure shows the MTF (modulation transfer function) curves of an embodiment of the present invention. The horizontal axis represents spatial frequency, with units of line pairs per millimeter (lp / mm), and the vertical axis represents the MTF value. As can be seen from the figure, the MTF curves of this embodiment exhibit high concentration, indicating excellent imaging consistency across the entire image plane, achieving high-resolution images across the entire plane. The MTF curves consistently maintain approximately 60% at 125 lp / mm across all fields of view.

[0054] Figure 3 The dot plot of this invention has all fields of view less than 1 pixel, which is sufficient for human eye viewing.

[0055] Figure 4 This is the vertical axis chromatic aberration diagram of the present invention. The horizontal axis represents the aberration of the image height between different colored lights and the reference colored light, and the vertical axis represents the field of view. From Figure 4 It can be seen that the entire color difference is within the Airy spot, and the vertical color difference is <1.35μm.

[0056] Figure 5 This is a distortion diagram of the present invention. The horizontal axis represents the percentage of distortion, and the vertical axis represents the field of view. From... Figure 5 It can be seen that the distortion in the entire image plane is below 0.7%.

[0057] The embodiments described above are only some embodiments of the present invention, and the concept and scope of the present invention are not limited to the details of the above exemplary embodiments. Therefore, various modifications and improvements made by other people skilled in the art based on the technical solutions of the present invention without departing from the design concept of the present invention should fall within the protection scope of the present invention, and all the contents of the claims are set forth in the claims.

Claims

1. A high-definition projection lens, characterized in that, From the object side to the image side, the lens consists of a negative power front lens group, an aperture stop, a positive power central focusing group, and a positive power rear lens group. The negative power front lens group includes a cemented doublet composed of a first lens with negative power and a second lens with positive power, a third lens with negative power, a fourth lens with negative power, a fifth lens with negative power and a sixth lens with positive power, and a seventh lens with positive power. The positive power central focusing group is composed of an eighth lens with positive power. The positive power rear lens group is composed of a cemented triplet composed of a ninth lens with negative power, a tenth lens with positive power, and an eleventh lens with negative power, and a twelfth lens with positive power. The aperture stop is located between the negative power front lens group and the positive power central focusing group. The high-definition projection lens has an F / # of 2.2, an FOV of 31°, and a TOTR of 183mm. The focal length of the high-definition projection lens is defined as f', the back focal length as lf', the image height of the optical module as 2y', the focal length of the negative optical power front lens group is defined as f'1, the focal length of the positive optical power central focusing group is defined as f'2, and the focal length of the positive optical power rear lens group is defined as f'3. The image height 2y' of the optical module and the focal length f' of the lens satisfy the following relationship: |2y' / f'| > 0.5; The focal length f'1 of the negative power front lens group and the focal length f' of the lens satisfy the following relationship: 1 < |f'1 / f'| < 2; The focal length f'2 of the focusing group in the positive focal length setting satisfies the relationship f' of the lens: |f'2 / f'| > 8; The focal length f'3 of the rear lens group with positive optical power satisfies the relationship f' of the lens: 3<|f'3 / f'|<4; The first lens has a front surface radius of 55.3 mm, a rear surface radius of 25 mm, a center thickness of 2 mm, a refractive index of 1.95, and an Abbe number of 17.

9. The second lens has a front surface radius of 25mm, a rear surface radius of 261mm, and a center thickness of: 10.6mm, refractive index: 1.73, Abbe number: 28.3; The third lens has a front surface radius of 31.3 mm, a rear surface radius of 16.9 mm, and a center thickness of: 1.5mm, refractive index: 1.88, Abbe number: 39.2; The fourth lens has a front surface radius of 57.3 mm, a rear surface radius of 22.4 mm, a center thickness of 1.3 mm, a refractive index of 1.95, and an Abbe number of 17.

9. The fifth lens has a front surface radius of -70.7 mm, a rear surface radius of 19.3 mm, a center thickness of 1.5 mm, a refractive index of 1.59, and an Abbe number of 68.

3. The sixth lens has a front surface radius of 19.3 mm, a rear surface radius of 42.5 mm, and a center thickness of: 4.8mm, refractive index: 1.81, Abbe number: 25.5; The seventh lens has a front surface radius of -147.3 mm, a rear surface radius of -44.9 mm, and a center thickness of: 3.8mm, refractive index: 1.85, Abbe number: 23.8; The eighth lens has a front surface radius of 44.5 mm, a rear surface radius of 86.3 mm, a center thickness of 3.6 mm, a refractive index of 1.95, and an Abbe number of 17.

9. The ninth lens has a front surface radius of 54.2 mm, a rear surface radius of 17.8 mm, and a center thickness of: 1.2mm, refractive index: 1.85, Abbe number: 23.8; The tenth lens has a front surface radius of 17.8 mm, a rear surface radius of -17.8 mm, and a center thickness of: 9.5mm, refractive index: 1.50, Abbe number: 81.6; The eleventh lens has a front surface radius of -17.8 mm, a rear surface radius of -51.2 mm, a center thickness of 2 mm, a refractive index of 1.54, and an Abbe number of 42.

7. The twelfth lens has a front surface radius of 47.7 mm, a rear surface radius of -35.4 mm, and a center thickness of: 7.5mm, refractive index: 1.61, Abbe number: 56.

7.

2. A high-definition projection lens according to claim 1, characterized in that, The first, second, fourth, sixth, seventh, eighth, and ninth lenses are made of heavy flint glass, wherein the first, fourth, and eighth lenses have a refractive index greater than 1.9; the third and eleventh lenses are made of heavy lanthanum flint glass with a refractive index greater than 1.84; the fifth lens is made of heavy phosphorus crown glass with a refractive index between 1.5 and 1.6; the tenth lens is made of fluorine crown glass with a refractive index less than 1.5; and the twelfth lens is made of heavy crown glass with a refractive index between 1.6 and 1.

7.

3. A high-definition projection lens according to claim 1, characterized in that, The first, second, third, fourth, sixth, seventh, eighth, ninth, and eleventh lenses adopt a meniscus structure, the fifth lens adopts a double concave structure, and the tenth and twelfth lenses adopt a double convex structure.

Images