Optical projection system and electronic equipment

Abstract

The present application discloses an optical projection system and an electronic device. The optical projection system includes, from the magnification side to the reduction side, a first lens group, a second lens group, a third lens group, and a fourth lens group. The first lens group has a negative optical focal length, the second lens group has a negative optical focal length, the third lens group has a positive optical focal length, and the fourth lens group has a positive optical focal length. The optical aperture of the optical projection system satisfies the following conditions: F#1.7 to F#2.0.

Description

Technical Field

[0001] The present application relates to the technical field of optical equipment, and more specifically, to an optical projection system and electronic equipment. Background Art

[0002] With the rapid development of science and technology, projection technology has become increasingly mature, and the application areas of projection equipment have become increasingly broad. For example, it is used in commercial fields such as conference presentations, road shows and promotional activities, in educational fields such as school lectures and academic discussions, and in domestic areas such as home theaters. In recent years, Digital Light Processing (DLP) projectors have become the mainstream technology for projectors. Due to its lightness, durability, high brightness, and high contrast, it is the preferred choice for projection display products.

[0003] In existing technology, the lens systems used in digital light processing (DLP) projection systems for 3D printing typically have small print sizes and low output power, making them difficult to meet the printing requirements of large-scale, high-power products. Therefore, developing a DLP projection system that can meet the requirements of high-precision 3D printing equipment has become a research topic within the industry. Summary of the Invention

[0004] One purpose of this application is to provide a new technical solution for an optical projection system and electronic equipment.

[0005] According to a first aspect of the present application, an optical projection system is provided, comprising, from a magnification side to a reduction side,:

[0006] a first lens group, a second lens group, a third lens group, and a fourth lens group;

[0007] The first lens group has a negative optical power, the second lens group has a negative optical power, the third lens group has a positive optical power, and the fourth lens group has a positive optical power;

[0008] The optical projection system has a light aperture of F#1.7 to F#2.0.

[0009] Optionally, the first lens group includes a first lens and a second lens arranged in sequence from the magnification side to the reduction side; the ratio of the focal length f1 of the first lens group to the focal length f of the optical projection system is greater than or equal to 2.1 and less than or equal to 2.6.

[0010] Optionally, the second lens group includes a third lens and a fourth lens arranged in sequence from the magnification side to the reduction side; the ratio of the focal length f2 of the second lens group to the focal length f of the optical projection system is greater than or equal to 4.6 and less than or equal to 5.0.

[0011] Optionally, the third lens group includes a fifth lens; and a ratio of a diameter of the fifth lens to a focal length f of the optical projection system is greater than or equal to 2.7 and less than or equal to 3.1.

[0012] Optionally, the fourth lens group includes a sixth lens, a seventh lens, an eighth lens, a ninth lens, a tenth lens and an eleventh lens arranged in sequence from the magnification side to the reduction side; a ratio of the focal length f4 of the fourth lens group to the focal length f of the optical projection system is greater than or equal to 1.2 and less than or equal to 1.5.

[0013] Optionally, there is a first air gap between the third lens group and the fourth lens group, and a ratio of the first air gap to the focal length f of the optical projection system is greater than or equal to 3.0 and less than or equal to 3.5.

[0014] Optionally, the optical projection system further includes a galvanometer and a prism, and the fourth lens group, the galvanometer and the prism are sequentially arranged in a direction from the magnification side to the reduction side.

[0015] Optionally, there is a second air gap between the fourth lens group and the prism, and a ratio of the second air gap to the focal length f of the optical projection system is greater than or equal to 0.85 and less than or equal to 0.95.

[0016] Optionally, the Abbe coefficient of the eleven lenses is less than 55.

[0017] According to a second aspect of the present application, an electronic device is provided, comprising the optical projection system as described in the first aspect.

[0018] In the optical projection system provided in the embodiment of the present application, through the optimized configuration of various parameters, it is possible to achieve an image effect with small projection image distortion, high relative illumination and high MTF modulation function.

[0019] Other features and advantages of the present application will become apparent from the following detailed description of exemplary embodiments of the present application with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the application and, together with the description, serve to explain the principles of the application.

[0021] Figure 1 Shown is a schematic diagram of the optical structure of an optical projection system of the present application;

[0022] Figure 2 Schematic diagram of field curvature and distortion of the optical projection system in Example 1 of the present application is shown;

[0023] Figure 3 Schematic diagram of relative illumination of the optical projection system in Example 1 of the present application;

[0024] Figure 4 Schematic diagram of the modulation transfer function of the optical projection system in Example 1 of the present application;

[0025] Figure 5 Schematic diagram of field curvature and distortion of the optical projection system in Example 2 of the present application;

[0026] Figure 6 Schematic diagram of relative illumination of the optical projection system in Example 2 of the present application;

[0027] Figure 7 Schematic diagram of the modulation transfer function of the optical projection system in Example 2 of the present application;

[0028] Figure 8 Schematic diagram of field curvature and distortion of the optical projection system in Example 3 of the present application is shown;

[0029] Figure 9 Schematic diagram of relative illumination of the optical projection system in Example 3 of the present application;

[0030] Figure 10 Shown is a schematic diagram of the modulation transfer function of the optical projection system in Example 3 of the present application.

[0031] Description of reference numerals:

[0032] 1. First lens; 2. Second lens; 3. Third lens; 4. Fourth lens; 5. Fifth lens; 6. Sixth lens; 7. Seventh lens; 8. Eighth lens; 9. Ninth lens; 10. Tenth lens; 11. Eleventh lens; 12. Galvanometer; 13. Prism; 14. Display chip protection glass; 15. Display chip. DETAILED DESCRIPTION

[0033] Various exemplary embodiments of the present application will now be described in detail with reference to the accompanying drawings. It should be noted that unless otherwise specifically stated, the relative arrangements of components and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present application.

[0034] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the present disclosure, its application, or uses.

[0035] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered part of the specification.

[0036] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0037] It should be noted that like reference numerals and letters refer to like items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0038] Reference Figure 1 As shown, according to one embodiment of the present application, an optical projection system is provided, which includes, from the magnification side to the reduction side, a first lens group, a second lens group, a third lens group and a fourth lens group; the optical focal power of the first lens group is negative, the optical focal power of the second lens group is negative, the optical focal power of the third lens group is positive, and the optical focal power of the fourth lens group is positive; the clear aperture of the optical projection system satisfies: F#1.7~F#2.0.

[0039] The optical projection system provided in the embodiment of the present application further includes a galvanometer 12, a prism 13, a display chip protective glass 14, and a display chip 15. Specifically, the prism 13 is an equivalent turning prism and is used to transmit light emitted or reflected by the display chip 15 to the lens. The display chip protective glass 14 is used to protect the display chip 15 from external influences such as electricity and contaminants. The display chip 15 can be a digital micromirror device display panel (DMD), a liquid crystal on silicon display panel (LCOS), a liquid crystal display panel (LCD), etc. It can be understood that the display chip 15 is a laser light source of different wavelengths or other light source capable of emitting light beams.

[0040] The optical projection system provided in the embodiment of the present application is applied to a projection device; the optical projection system includes a reduction side and an amplification side along the direction of light transmission, and the display chip 15, the display chip protection glass 14, the prism 13, the galvanometer 12, the fourth lens group, the third lens group, the second lens group and the first lens group in the optical projection system are sequentially arranged between the reduction side and the amplification side along the same optical axis. Among them, the reduction side is the side where the image source (such as the display chip 15) that generates the projection light is located during the projection process, that is, the image side; the amplification side is the side where the projection surface (such as the projection screen) used to display the projection image is located during the projection process, that is, the object side. The transmission direction of the projection light is from the reduction side to the amplification side. However, when actually designing the optical projection system, according to the principle of reversibility of the light path, the light is simulated from the actual amplification side to the reduction side.

[0041] Specifically, during the actual projection process, the projection light is emitted by the display chip 15, emitted from the reduction side toward the magnification side, and passes through the display chip protective glass 14, prism 13, galvanometer 12, fourth lens group, third lens group, second lens group and first lens group in sequence, thereby displaying the projected image.

[0042] In the embodiment of the present application, the display chip 15 serving as the image source may be a digital micromirror device (DMD) chip. The DMD is composed of many digital micromirrors arranged in a matrix. During operation, each micromirror can be deflected and locked in both positive and negative directions, thereby projecting light in a predetermined direction. The micromirrors oscillate at a frequency of tens of thousands of hertz, reflecting the light beam from the illumination source into the optical system and forming an image on the screen. The DMD has advantages such as high resolution and the absence of digital-to-analog conversion. This embodiment uses a 0.3-inch DMD. Of course, the display chip 15 serving as the image source may also be a liquid crystal on silicon (LCOS) chip, a liquid crystal display (LCD) panel, or other display element that can be used to emit light, and this application does not impose any restrictions on this.

[0043] In this embodiment, the first lens group has a negative optical power, the second lens group has a negative optical power, the third lens group has a positive optical power, and the fourth lens group has a positive optical power. By rationally matching the optical powers of each lens group, the optical power of the entire optical projection system is balanced, meeting the image quality requirements of 3D printing. The first and second lens groups are both negative lenses, which can reduce distortion and help meet the low distortion requirements of 3D printing. Specifically, distortion can be controlled within 0.22%, ensuring that the 3D printed product does not deform. The third and fourth lens groups are both positive lens groups, which helps meet the high-resolution image requirements of 3D printing (actually manifested as an MTF of 0.6 or above).

[0044] Moreover, generally speaking, 3D printing systems usually use a wavelength of 385nm to 405nm, and the light source utilization efficiency is low, making it difficult to meet the power requirements of large-scale printed components. The optical projection system provided in the embodiment of the present application has a light aperture that meets the following requirements: F#1.7 to F#2.0. This can achieve the goal of a large light aperture lens while meeting the light power requirements, thereby greatly improving the power of 3D printing. The light aperture in the range of F#1.7 to F#2.0 can achieve a projection screen with a larger size range that meets the power requirements of 3D printing; in the optical projection system provided in the embodiment of the present application, a large light aperture 3D printing lens system in the range of F#1.7 to F#2.0 is used, and its DMD adopts 0.3 inches, a wavelength of 385nm to 405nm, and a projection screen range of 6.0 inches to 9.5 inches, which meets the printing power requirements of any projection screen within the projection screen size range.

[0045] Furthermore, the provision of the galvanometer mirror 12 can improve the resolution of the optical projection system. The galvanometer mirror 12 is used to double the pixels of light emitted or reflected by the display chip 15 in both the length and width directions (e.g., a 0.3DMD pixel is 1280×720, which is 2560×1440 after expansion by the galvanometer mirror 12) before transmitting it to the 3D printing lens, thereby meeting the large aperture and large-scale printing precision requirements of the 3D printing system.

[0046] In one embodiment, the first lens group includes a first lens 1 and a second lens 2 arranged in sequence from the magnification side to the reduction side; a ratio of the focal length f1 of the first lens group to the focal length f of the optical projection system is greater than or equal to 2.1 and less than or equal to 2.6.

[0047] In one embodiment, the second lens group includes a third lens 3 and a fourth lens 4 arranged in sequence from the magnification side to the reduction side; the ratio of the focal length f2 of the second lens group to the focal length f of the optical projection system is greater than or equal to 4.6 and less than or equal to 5.0.

[0048] In one embodiment, the fourth lens group includes a sixth lens 6, a seventh lens 7, an eighth lens 8, a ninth lens 9, a tenth lens 10, and an eleventh lens 11, which are arranged in sequence from the magnification side to the reduction side; and a ratio of the focal length f4 of the fourth lens group to the focal length f of the optical projection system is greater than or equal to 1.2 and less than or equal to 1.5.

[0049] In this specific example, by limiting the ratios of the focal length f1 of the first lens group, the focal length f2 of the second lens group, and the focal length f4 of the fourth lens group to the focal length f of the optical projection system, the radial dimension of the optical projection system can be effectively reduced while meeting the imaging quality, which is conducive to the lightweight and miniaturized design of the optical projection system.

[0050] In addition, the fourth lens group is arranged relatively compactly, which can effectively improve the MTF of the lens to above 0.68%, ensuring the printing accuracy requirements of the large-aperture 3D printing lens system.

[0051] In one embodiment, the third lens group includes a fifth lens 5 ; a ratio of a diameter of the fifth lens 5 to a focal length f of the optical projection system is greater than or equal to 2.7 and less than or equal to 3.1.

[0052] In this specific example, by limiting the ratio of the diameter of the fifth lens 5 to the focal length f of the optical projection system, this lens diameter can meet the requirement of a large clear aperture lens to achieve a relative illumination of more than 90%, thereby ensuring the consistency of the 3D printed parts.

[0053] In one embodiment, a first air space is defined between the third lens group and the fourth lens group, and a ratio of the first air space to a focal length f of the optical projection system is greater than or equal to 3.0 and less than or equal to 3.5.

[0054] In the optical projection system, the diaphragm is arranged between the third lens group and the fourth lens group. By limiting the first air space between the third lens group and the fourth lens group, it is ensured that the setting of the diaphragm meets the requirements of the large clear aperture lens.

[0055] In one embodiment, a second air gap is defined between the fourth lens group and the prism 13 , and a ratio of the second air gap to the focal length f of the optical projection system is greater than or equal to 0.85 and less than or equal to 0.95.

[0056] In this specific example, the spacing between the fourth lens group and the prism 13 can ensure that a galvanometer can be placed in the large-aperture 3D printing lens system, thereby improving printing accuracy.

[0057] Furthermore, by optimizing the ratio of the first air space and the second air space to the focal length f of the optical projection system, the image quality can be effectively improved and the total length of the optical lens group can be reduced, thereby achieving lightness, thinness and miniaturization.

[0058] In one embodiment, the Abbe coefficient of the eleven lenses 11 is less than 55.

[0059] Because the closer an optical projection system is to a light source during operation, its temperature increases. Therefore, the lens material near the light source must be made of a glass material with good thermal stability. In this specific example, the eleven lenses 11 closest to the light source (i.e., display chip 15) are made of a glass material with a good thermal stability and an Abbe coefficient less than 55. This meets the requirements of the 3D printing system for maintaining lens deformation and image value drift under continuous high-temperature operation.

[0060] In addition, the remaining lenses are also made of glass, which can effectively reduce the impact of thermal drift on 3D printing accuracy. Furthermore, it can transmit shorter wavelength purple light, which has a wavelength range of 380nm-420nm.

[0061] Reference Figure 1 As shown, the magnifying side surface of the first lens 1 is convex, and the reducing side surface is concave; the magnifying side surface of the second lens 2 is convex, and the reducing side surface is concave; the magnifying side surface of the third lens 3 is convex, and the reducing side surface is concave; the magnifying side surface of the fourth lens 4 is a plane, and the reducing side surface is concave; the magnifying side surface of the fifth lens 5 is convex, and the reducing side surface is convex; the magnifying side surface of the sixth lens 6 is concave, and the reducing side surface is a plane; the magnifying side surface of the seventh lens 7 is concave, and the reducing side surface is convex; the magnifying side surface of the eighth lens 8 is concave, and the reducing side surface is convex; the magnifying side surface of the ninth lens 9 is concave, and the reducing side surface is convex; the magnifying side surface of the tenth lens 10 is convex, and the reducing side surface is convex; the magnifying side surface of the eleventh lens 11 is convex, and the reducing side surface is concave.

[0062] In this specific example, the above-mentioned structural design enables the entire optical projection system to meet the image value requirements and light convergence capabilities of 3D printing.

[0063] The optical projection system provided in the embodiments of the present application has a projected image with low distortion, high relative illumination, and a high MTF modulation function. By optimizing the above parameters, it can achieve a projected image distortion of less than 0.22%, a relative illumination of greater than 90%, and an MTF modulation function of greater than 0.6, ensuring the consistency of 3D printed parts, as well as high precision and deformation-free printing.

[0064] According to another embodiment of the present application, an electronic device is provided, comprising the optical projection system described above. The electronic device may be, for example, a projection device, such as a projector or an illumination light machine.

[0065] Example 1:

[0066] Reference Figure 1 As shown, from the magnification side to the reduction side, the optical projection system is sequentially provided with a first lens 1, a second lens 2, a third lens 3, a fourth lens 4, a fifth lens 5, an aperture, a sixth lens 6, a seventh lens 7, an eighth lens 8, a ninth lens 9, a tenth lens 10, an eleventh lens 11, a galvanometer 12, a prism 13, a display chip protection glass 14 and a display chip 15.

[0067] The parameters involved in Example 1 are shown in Table 1 below:

[0068] Table 1

[0069]

[0070]

[0071] Reference Figure 2 As shown, the meridional field curvature and sagittal field curvature of the optical projection system in Example 1 are both within the range of ±0.03mm in the entire field of view, and the optical distortion of the maximum field of view is within the range of 0.22%, which can meet the lens distortion requirements for 3D printing. Figure 3 As shown, the relative illumination of the optical projection system is 100%, which meets the requirement of 3D printing brightness uniformity greater than 93%. Figure 4 As shown, the modulation transfer function of the optical projection system is greater than 0.68 in each field of view, meeting the accuracy requirements of 3D printing.

[0072] Example 2:

[0073] Reference Figure 1 As shown, from the magnification side to the reduction side, the optical projection system is sequentially provided with a first lens 1, a second lens 2, a third lens 3, a fourth lens 4, a fifth lens 5, an aperture, a sixth lens 6, a seventh lens 7, an eighth lens 8, a ninth lens 9, a tenth lens 10, an eleventh lens 11, a galvanometer 12, a prism 13, a display chip protection glass 14 and a display chip 15.

[0074] The parameters involved in Example 2 are shown in Table 2 below:

[0075] Table 2

[0076]

[0077]

[0078] Reference Figure 5 As shown, the meridional field curvature and sagittal field curvature of the optical projection system in Example 2 are both within the range of ±0.03mm in the entire field of view, and the optical distortion of the maximum field of view is within the range of 0.22%, which can meet the lens distortion requirements for 3D printing. Figure 6 As shown, the relative illumination of the optical projection system is 100%, which meets the requirement of 3D printing brightness uniformity greater than 93%. Figure 7 As shown, the modulation transfer function of the optical projection system is greater than 0.62 in each field of view, meeting the accuracy requirements of 3D printing.

[0079] Example 3:

[0080] Reference Figure 1As shown, from the magnification side to the reduction side, the optical projection system is sequentially provided with a first lens 1, a second lens 2, a third lens 3, a fourth lens 4, a fifth lens 5, an aperture, a sixth lens 6, a seventh lens 7, an eighth lens 8, a ninth lens 9, a tenth lens 10, an eleventh lens 11, a galvanometer 12, a prism 13, a display chip protection glass 14 and a display chip 15.

[0081] The parameters involved in Example 3 are shown in Table 3 below:

[0082] Table 3

[0083]

[0084] Reference Figure 8 As shown, the meridional field curvature and sagittal field curvature of the optical projection system in Example 3 are both within the range of ±0.03mm in the entire field of view, and the optical distortion of the maximum field of view is within the range of 0.22%, which can meet the lens distortion requirements for 3D printing. Figure 9 As shown, the relative illumination of the optical projection system is 100%, which meets the requirement of 3D printing brightness uniformity greater than 93%. Figure 10 As shown, the modulation transfer function of the optical projection system is greater than 0.6 in each field of view, meeting the accuracy requirements of 3D printing.

[0085] Although some specific embodiments of the present application have been described in detail by way of examples, it should be understood by those skilled in the art that the above examples are for illustration only and are not intended to limit the scope of the present application. It should be understood by those skilled in the art that the above embodiments may be modified without departing from the scope and spirit of the present application. The scope of the present application is defined by the appended claims.

Claims

1. An optical projection system, characterized in that: From the magnification side to the reduction side, they include: There are four lens groups in total: the first lens group, the second lens group, the third lens group and the fourth lens group; The first lens group has a negative optical power, the second lens group has a negative optical power, the third lens group has a positive optical power, and the fourth lens group has a positive optical power; The optical projection system has a clear aperture of F#1.7 to F#2.0; wherein the first lens group is composed of a first lens (1) with negative optical power and a second lens (2) with negative optical power, which are arranged in sequence from the magnification side to the reduction side; the second lens group is composed of a third lens (3) with negative optical power and a fourth lens (4) with negative optical power, which are arranged in sequence from the magnification side to the reduction side; the third lens group is composed of a fifth lens (5) with positive optical power; the fourth lens group is composed of a sixth lens (6) with negative optical power, a seventh lens (7) with positive optical power, an eighth lens (8) with positive optical power, a ninth lens (9) with positive optical power, a tenth lens (10) with positive optical power, and an eleventh lens (11) with positive optical power, which are arranged in sequence from the magnification side to the reduction side; An absolute value of a ratio of a focal length f1 of the first lens group to a focal length f of the optical projection system is greater than or equal to 2.1 and less than or equal to 2.

6.

2. The optical projection system according to claim 1, wherein: The ratio of the diameter of the fifth lens (5) to the focal length f of the optical projection system is greater than or equal to 2.7 and less than or equal to 3.

1.

3. The optical projection system according to claim 1, wherein: The optical projection system further comprises a galvanometer mirror (12) and a prism (13), and the fourth lens group, the galvanometer mirror (12), and the prism (13) are arranged in sequence along a direction from the magnification side to the reduction side.

4. The optical projection system according to claim 3, wherein: A second air gap is provided between the fourth lens group and the prism (13), and a ratio of the second air gap to the focal length f of the optical projection system is greater than or equal to 0.85 and less than or equal to 0.

95.

5. The optical projection system according to claim 1, wherein: The Abbe coefficient of the eleven lenses (11) is less than 55.

6. An electronic device, characterized in that: The electronic device comprises the optical projection system according to any one of claims 1 to 5.

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