WO2023184752A1

WO2023184752A1 - Optical projection system and electronic device

Info

Publication number: WO2023184752A1
Application number: PCT/CN2022/101699
Authority: WO
Inventors: 郭恒琳; 王显彬
Original assignee: 歌尔光学科技有限公司
Priority date: 2022-03-31
Filing date: 2022-06-28
Publication date: 2023-10-05
Also published as: CN114740600A

Abstract

An optical projection system and an electronic device. The optical projection system comprises, from an amplification side to a reduction side, a first lens (1), a second lens (2), a third lens (3), a fourth lens (4), a fifth lens (5), and a sixth lens (6); an effective focal length eff of the optical projection system is: 4.5mm<eff<6.7mm; and the optical projection system satisfies the following relationship: 3.5<TL/D<5, wherein TL represents a total optical length of the optical projection system, and D represents a maximum lens aperture in the optical projection system.

Description

An optical projection system and electronic device

Technical field

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

Background technique

At present, optical projection systems are developing rapidly and have a wide range of applications. For example, projection optical systems are used in digital light processing (DLP) projection equipment, augmented reality technology (Augmented Reality, AR) equipment and virtual reality (Virtual Reality, VR) equipment. The design of the optical projection system directly determines the imaging clarity, screen size, and image quality of the screen distortion of the projection product.

Therefore, how to design an optical system with a 0.2-inch DMD luminous surface, a throw ratio of 1.1, and good imaging quality while reducing the size of the imaging system is one of the issues that designers in the field of optical design urgently need to solve.

Contents of the invention

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

According to a first aspect of embodiments of the present application, an optical projection system is provided. The optical projection system includes:

From the magnification side to the reduction side, it includes: a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens. The effective focal length of the optical projection system is: 4.5mm<eff<6.7mm , the optical projection system satisfies the following relationship: 3.5<TL/D<5, where TL is the total optical length of the optical projection system, and D is the maximum lens diameter in the optical projection system.

Optionally, from the magnification side to the reduction side, the optical power order of the optical projection system is: negative, negative, positive/positive, negative, positive.

Optionally, the fourth lens and the fifth lens are cemented to form a first cemented lens, or the fourth lens and the fifth lens are cemented to form a first cemented lens, and the second lens and the The third lens is cemented and connected to form a second cemented lens.

Optionally, the distance between the second lens and the third lens is d1, and the distance between the first lens and the sixth lens is L, where: d1/L<0.2.

Optionally, the distance between the first lens and the sixth lens is L, and the distance between the third lens and the fourth lens is d2, where d2/L<0.5.

Optionally, an aperture is provided between the third lens and the fourth lens, the distance between the third lens and the aperture is d3, and the distance between the fourth lens and the aperture is d3. The distance is d4, where 0.7<d3/d4<1.3.

Optionally, the first lens has a first surface facing away from the second lens, and the first lens has a second surface disposed adjacent to the second lens, the radius of the first surface is D1, and the second surface has a radius of D1. The radius of the surface is D2, where 2≤D1/D2≤5.

Optionally, the optical projection system satisfies the following relationships: -10mm<f1<-6.6mm, -20mm<f2<-16.7mm, 6mm<f3<11mm, 9mm<f4<13mm, -15mm<f5<-9mm ,7mm<f6<12.6mm;

Wherein, f1 is the effective focal length of the first lens, f2 is the effective focal length of the second lens, f3 is the effective focal length of the third lens, f4 is the effective focal length of the fourth lens, and f5 is the effective focal length of the fourth lens. The effective focal length of the fifth lens, f6, is the effective focal length of the sixth lens.

Optionally, the first surface of the first lens is a convex surface, the second surface of the first lens is a concave surface; the second surface of the second lens is a concave surface; the first surface of the third lens and The second surfaces are both convex; the first surface of the fourth lens is concave or flat, the second surface of the fourth lens is convex; the first surface of the fifth lens is concave, and the fifth lens The second surface of the sixth lens is a convex surface; the first surface and the second surface of the sixth lens are both convex surfaces; wherein, the first surface of each lens is located closer to the magnifying side than its second surface.

According to a second aspect of the embodiment of the present application, an electronic device is provided, and the electronic device includes the optical projection system as described in the first aspect.

In the embodiment of the present application, an optical projection system is provided. By limiting the number of lenses in the optical projection system, the effective focal length of the optical projection system, and the ratio of the total optical length of the optical projection system to the maximum lens diameter, the optical projection system is The compact structure of the system reduces the size of the optical projection system and improves the imaging quality of the optical projection system.

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.

Description of drawings

In order to explain the embodiments of the present application or the technical solutions in the prior art more clearly, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings in the following description are only These are part of the drawings of this application. For those of ordinary skill in the art, other drawings can be obtained based on the provided drawings without exerting creative efforts.

Figure 1 shows a schematic structural diagram of the optical projection system of the present application.

Figure 2 shows the second structural schematic diagram of the optical projection system of the present application.

Figure 3 shows the first modulation transfer function diagram of each field of view of an embodiment of the optical projection system of the present application.

Figure 4 shows the second diagram of the modulation transfer function of each field of view of an embodiment of the optical projection system of the present application.

Figure 5 shows a defocus curve of an embodiment of the optical projection system of the present application.

Figure 6 shows the modulation transfer function of each field of view of another embodiment of the optical projection system of the present application.

Figure 7 shows a defocus curve of another embodiment of the optical projection system of the present application.

Explanation of reference symbols:

1. First lens; 2. Second lens; 3. Third lens; 4. Fourth lens; 5. Fifth lens; 6. Sixth lens; 7. Diaphragm; 8. Image source; 9. Flat glass ; 10. Prism; 20. First lens group; 30. Second lens group.

Detailed ways

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

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

Techniques and equipment known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, such techniques and equipment should be considered a part of the specification.

In all examples shown and discussed herein, any specific values are to be construed as illustrative only and not as limiting. Accordingly, other examples of the exemplary embodiments may have different values.

It should be noted that similar reference numerals and letters refer to similar items in the following figures, so that once an item is defined in one figure, it does not need further discussion in subsequent figures.

This application provides an optical projection system, which is applied to a projection device. For example, the optical projection system can be applied to projection light machines, lighting light machines, etc. Or the optical projection system can be applied to AR (augmented reality) devices or VR (virtual reality) devices.

VR (Virtual Reality) is a computer simulation system that can create and experience a virtual world. It uses computers to generate a simulated environment. It is a multi-information fusion, interactive three-dimensional dynamic vision and entity behavior. System simulation immerses the user in the environment. The optical projection system of this application is used in VR to improve the imaging screen of the VR device while reducing the volume of the VR device.

AR (Augmented Reality) is a technology that uses computer systems to generate virtual image information to increase users' perception of the real world. AR technology is committed to superimposing computer-generated virtual objects, images, text and other information onto real scenes to create a world that combines virtual and real scenes, and realizes the interaction of virtual and real scenes through image recognition, tracking, registration technology, cloud technology, etc., thereby realizing "Augmentation" of the real world. The optical projection system of this application is applied to VR, which improves the imaging image of the AR device while reducing the size of the AR device.

Referring to Figures 1 and 2, from the magnification side to the reduction side, the optical projection system includes: a first lens 1, a second lens 2, a third lens 3, a fourth lens 4, a fifth lens 5 and a sixth lens 6 , the effective focal length of the optical projection system is: 4.5mm<eff<6.7mm, the optical projection system satisfies the following relationship: 3.5<TL/D<5, where TL is the total optical length of the optical projection system, and D is the optical projection The largest lens diameter in the system.

In this embodiment, including the reduction side and the magnification side along the light transmission direction, the image source 8, the flat glass 9, the prism 10, the sixth lens 6, the fifth lens 5, the fourth lens 4, the third lens in the optical projection system The lens 3, the second lens 2, and the first lens 1 are sequentially arranged between the reduction side and the magnification side along the same optical axis. Among them, the reducing side is the side where the image source 8 (such as the DMD chip) that generates the projection light is located during the projection process, that is, the image side; the zooming side is the projection surface (such as the projection screen) used to display the projected image during the projection process. ) is located on the side, that is, the object side. The transmission direction of the projection light is from the reduction side to the magnification side. However, when actually designing the optical projection system, according to the principle of reversible light path, the light is simulated from the actual magnification side to the reduction side.

Specifically, during the actual projection process, the projection light is emitted from the image source 8, emitted from the reduction side toward the magnification side, and passes through the flat glass 9, prism 10, sixth lens 6, fifth lens 5, fourth lens 4, The third lens 3, the second lens 2 and the first lens 1 thereby display the projected image.

In the embodiment of the present application, the image source 8 may be a Digital Micromirror Device (DMD) chip. DMD is composed of many digital micro-mirrors arranged in a matrix. When working, each micro-mirror can be deflected and locked in both forward and reverse directions, so that light is projected in a predetermined direction and at a frequency of tens of thousands of Hertz. Swinging, the light beam from the illumination source is reflected on the flip of the micro-mirror and enters the optical system to be imaged on the screen. DMD has the advantages of high resolution and no need for digital-to-analog conversion of signals. This embodiment is suitable for 0.2" DMD, throw ratio 1:1, 160% offset (off-axis) design. Specifically, this embodiment is suitable for 0.2" DMD with an aspect ratio of 16:9 and a specific size of 4.6116 *2.592mm, using design throw ratio of 1.1 and max_offset of 160%. Of course, the image source 8 can also be a Liquid Crystal On Silicon (LCOS) chip or other display elements that can be used to emit light, and this application does not limit this.

In this embodiment, the optical projection system design of this application is based on the optical path architecture of the imaging design with a 0.2" DMD light-emitting surface size and a throw ratio of 1.1, which is different from the current seven-lens architecture or more lens architecture. This application The optical projection system only includes six lenses, which reduces the volume of the optical projection system; at the same time, the optical projection system of this embodiment satisfies the following relationship: 3.5<TL/D<5, where TL is the total optical length of the optical projection system (the total optical length is : the distance between the vertex of the light exit surface of the first lens 1 and the back of the image source 8 (the surface facing away from the sixth lens 6) along the optical axis direction), D is the maximum lens diameter in the optical projection system, which can be Controlling the total length and radius of the optical projection system makes the structure of the optical projection system compact, thereby ensuring the small size of the optical projection system to a certain extent and making the optical projection system easy to carry and use.

In this embodiment, the effective focal length of the optical projection system is limited to this range, which improves the imaging effect of the optical projection system while reducing the volume of the optical projection system. Specifically, embodiments of the present application limit the effective focal length of the optical projection system so that the full field of view MTF of the optical projection system satisfies >0.5@96lp/mm, thereby improving the imaging quality of the optical projection system.

In one embodiment, from the magnification side to the reduction side, the optical power order of the optical projection system is: negative, negative, positive/positive, negative, positive.

In this embodiment, the optical power order of the optical projection system is negative negative positive/positive negative positive. That is, in the optical projection system, the first lens 1, the second lens 2 and the third lens 3 constitute the first lens group 20. The fourth lens 4 , the fifth lens 5 and the sixth lens 6 constitute the second lens group 30 . In this embodiment, the optical power of the first lens group 20 is negative, and the optical power of the second lens group 30 is positive. The optical power of the first lens group 20 and the second lens group 30 is reasonably distributed to balance the overall optical power of the optical projection system.

In one embodiment, the fourth lens 4 and the fifth lens 5 are cemented to form a first cemented lens, or the fourth lens 4 and the fifth lens 5 are cemented to form a first cemented lens, and the The second lens 2 and the third lens 3 are cemented and connected to form a second cemented lens.

In this embodiment, the first lens 1 , the second lens 2 and the third lens 3 are combined to form a first lens group 20 , and the first lens group 20 is the front lens group of the optical projection system. The fourth lens 4 , the fifth lens 5 and the sixth lens 6 are combined to form a second lens group 30 , and the second lens group 30 is the rear lens group of the optical projection system.

In one embodiment, as shown in FIG. 2 , in the second lens group 30 , the fourth lens 4 and the fifth lens 5 are cemented and connected to form a first cemented lens. That is, the rear lens group includes a cemented lens, which can effectively reduce chromatic aberration produced during the optical imaging process.

In another embodiment, as shown in FIG. 1 , in the first lens group 20 , the second lens 2 and the third lens 3 are glued and connected to form a second cemented lens, and at the same time, in the second lens group 30 , the fourth The lens 4 and the fifth lens 5 are cemented and connected to form a first cemented lens. That is, the front lens group contains a cemented lens, and the rear lens group contains a cemented lens. Specifically, the optical projection system includes six lenses, as well as the two lenses in the front lens group close to the aperture 7 that are glued together, and the two lenses in the rear lens group that are close to the aperture 7 that are glued together. Combined with the 0.2" DMD size requirements, With the 160% offset requirement, the chromatic aberration produced during the optical imaging process can be further reduced.

In this embodiment, for the entire optical projection system, the first lens 1 is mainly used to reduce imaging distortion. The sixth lens 6 and the first lens 1 are mainly used to eliminate spherical aberration of imaging. The second lens 2 and the third lens 3 are glued and connected, mainly used to further eliminate imaging chromatic aberration; the fourth lens 4 and the fifth lens 5 are glued and connected, mainly used to eliminate imaging chromatic aberration.

In one embodiment, referring to FIG. 2 , the distance between the second lens 2 and the third lens 3 is d1, and the distance between the first lens 1 and the sixth lens 6 is L, Among them: d1/L<0.2.

In this embodiment, the second lens 2 and the third lens 3 are provided separately. In this embodiment, based on the above-mentioned optical projection system structure, (the above-mentioned optical projection system structure is: the optical projection system includes six lenses, from the magnification side to the reduction side, the power order of the six lenses is: negative Negative positive/positive negative positive, and the effective focal length of the academic projection system is: 4.5mm<eff<6.7mm, the optical projection system satisfies the following relationship: 3.5<TL/D<5, where TL is the total optical length of the optical projection system, D is the maximum lens diameter in the optical projection system), and then limits the distance ratio between lenses to optimize the optical projection system.

Specifically, in the first lens group 20 , if the second lens 2 and the third lens 3 are not glued together, that is, the second lens 2 and the third lens 3 are arranged separately, there is no gap between the second lens 2 and the third lens 3 . The distance is d1, that is, the distance between the two adjacent surfaces of the second lens 2 and the third lens 3 is d1. The distance between the first lens 1 and the sixth lens 6 is L, that is, along the optical axis direction, the distance between the light incident surface of the first lens 1 and the light exit surface of the sixth lens 6 is L. Refer to Figure 2, that is The distance between the S2 surface and the S11 surface is L.

This embodiment limits the ratio between the distance between the second lens 2 and the third lens 3 and the distance between the first lens 1 and the sixth lens 6 to optimize the parameters of the optical projection system. Specifically, when the optical imaging system is matched with the 0.2" DMD size requirement and the 160% offset design requirement, the optical projection system can obtain a high-quality picture with small distortion and small chromatic aberration of the imaging picture. If d1/L is not within this range, the optical The image quality of the projection system is poor.

In an optional embodiment, the distance between the second lens 2 and the third lens 3 is d1, and the distance between the first lens 1 and the sixth lens 6 is L, where: d1 /L<0.2, at the same time, the distance between the first lens 1 and the sixth lens 6 is L, and the distance between the third lens 3 and the fourth lens 4 is d2, where d2/L<0.5. The optical imaging system is matched with 0.2" DMD size requirements and 160% offset design requirements. The optical projection system can obtain high-quality images with small distortion, small chromatic aberration and small spherical aberration.

In one embodiment, referring to Figure 1, the distance between the first lens 1 and the sixth lens 6 is L, the distance between the third lens 3 and the fourth lens 4 is d2, Among them d2/L<0.5.

In this embodiment, the second lens 2 and the third lens 3 are glued and connected. In this embodiment, based on the above-mentioned optical projection system structure, (the above-mentioned optical projection system structure is: the optical projection system includes six lenses, from the magnification side to the reduction side, the power order of the six lenses is: negative Negative positive/positive negative positive, and the effective focal length of the academic projection system is: 4.5mm<eff<6.7mm, the optical projection system satisfies the following relationship: 3.5<TL/D<5, where TL is the total optical length of the optical projection system, D is the maximum lens diameter in the optical projection system), and then limits the distance ratio between lenses to optimize the optical projection system.

In this embodiment, the distance between the third lens 3 and the fourth lens 4 is d2, that is, the distance between the third lens 3 and the fourth lens 4 on the optical axis is d2. In the optical projection system, the first lens 1, the second lens 2 and the third lens 3 constitute a first lens group 20. The fourth lens 4, the fifth lens 5 and the sixth lens 6 constitute the second lens group 30, that is, the distance between the first lens group 20 and the second lens group 30 is d2. Referring to Figure 1, the distance between the S5 surface and the S8 surface is d2. The distance between the first lens 1 and the sixth lens 6 is L, that is, along the optical axis direction, the distance between the light incident surface of the first lens 1 and the light exit surface of the sixth lens 6 is L. Refer to Figure 2, that is The distance between the S2 surface and the S11 surface along the optical axis is L.

This embodiment limits the ratio between the distance between the third lens 3 and the fourth lens 4 and the distance between the first lens 1 and the sixth lens 6 to further optimize the imaging parameters of the optical projection system. Specifically, the optical imaging system is suitable for 0.2” DMD size requirements, and the 160% offset design improves the imaging quality of the optical imaging system and reduces the spherical aberration and chromatic aberration of imaging.

In one embodiment, as shown in FIGS. 1 and 2 , an aperture 7 is provided between the third lens 3 and the fourth lens 4 , and the distance between the third lens 3 and the aperture 7 is is d3, and the distance between the fourth lens 4 and the aperture 7 is d4, where 0.7<d3/d4<1.3.

In this embodiment, the diaphragm 7 is provided between the third lens 3 and the fourth lens 4 , that is, the diaphragm 7 is provided between the first lens group 20 and the second lens group 30 . The distance between the third lens 3 closest to the aperture 7 in the first lens group 20 and the aperture 7 is d3. The distance between the fourth lens 4 closest to the aperture 7 in the second lens group 30 and the aperture 7 is d3. The distance between them is d4. Among them, 0.7<d3/d4<1.3. This embodiment limits the distance between the third lens 3 and the diaphragm 7 and the ratio of the distance between the fourth lens 4 and the diaphragm 7. On the one hand, it achieves the purpose of reducing the total optical length and miniaturizing the optical projection system. On the other hand, it can better correct spherical aberration and image distortion.

In one embodiment, as shown in FIGS. 1 and 2 , the first lens 1 has a first surface facing away from the second lens 2 , and the first lens 1 has a second surface disposed adjacent to the second lens 2 , the radius of the first surface is D1, and the radius of the second surface is D2, where 2≤D1/D2≤5.

In this embodiment, the ratio between the radius of the first surface in the first lens 1 and the radius of the second surface in the first lens 1 is defined. The radius of the first surface is greater than the radius of the second surface, and at the same time, 2≤D1 /D2≤5, for example, D1/D2=2, or D1/D2=3; D1/D2=4; D1/D2=5.

Specifically, the ratio of the radius of the first surface of the first lens 1 to the radius of the second surface of the first lens 1 is defined to define the shape of the first lens 1 . The first lens 1 is meniscus-shaped and can achieve a large field of view. At the same time, the first lens 1 can better eliminate distortion and improve the imaging quality of the optical projection system.

In one embodiment, the optical projection system satisfies the following relationships: -10mm<f1<-6.6mm, -20mm<f2<-16.7mm, 6mm<f3<11mm, 9mm<f4<13mm, -15mm<f5< -9mm, 7mm<f6<12.6mm;

Wherein, f1 is the effective focal length of the first lens 1, f2 is the effective focal length of the second lens 2, f3 is the effective focal length of the third lens 3, f4 is the effective focal length of the fourth lens 4, f5 is the effective focal length of the fifth lens 5 , and f6 is the effective focal length of the sixth lens 6 .

In this embodiment, the effective focal length of each lens is limited to improve the imaging quality of the optical projection system.

In one embodiment, the first surface of the first lens 1 is a convex surface, the second surface of the first lens 1 is a concave surface; the second surface of the second lens 2 is a concave surface; and the third lens The first surface and the second surface of 3 are both convex surfaces; the first surface of the fourth lens 4 is a concave surface or a flat surface, the second surface of the fourth lens 4 is a convex surface; the first surface of the fifth lens 5 The first surface of the fifth lens 5 is a concave surface, and the second surface of the fifth lens 5 is a convex surface. The first surface and the second surface of the sixth lens 6 are both convex surfaces. The first surface of each lens is more convex than its second surface. Set close to the magnification side.

Specifically, the first lens 1 is a meniscus lens with negative refractive power; the second lens 2 is a lens with negative refractive power, for example, the second lens 2 is a biconcave lens with negative refractive power, or is a lens with negative refractive power. A meniscus lens with negative power; the third lens 3 is a biconvex lens with positive power; and the second lens 2 and the third lens 3 are cemented together; the fourth lens 4 has a meniscus lens with a positive focal length, or the fourth Lens 4 is a plano-convex lens with positive focal length; the fifth lens 5 with negative refractive power is a meniscus lens, and the fourth lens 4 and the fifth lens 5 are cemented together; the sixth lens 6 is a biconvex lens with positive refractive power.

A double cemented lens composed of the second lens 2 and the third lens 3, and a double cemented lens composed of the fourth lens 4 and the fifth lens 5. The optical projection system is suitable for 0.2” DMD, throw ratio 1:1, 160% offset (off-axis) design can effectively reduce the chromatic aberration generated during the optical imaging process. The embodiment of the present application limits the surface shape and optical power of each lens in the optical projection system, and also limits the number of lenses in the optical projection system. Limited, the optical projection system is suitable for 0.2” DMD, the throw ratio is 1:1, and the 160% offset (off-axis) design improves the imaging quality of the optical projection system.

According to a second aspect of the embodiment of the present application, an electronic device is provided. The electronic device includes the optical projection system described in the first aspect. For example, the electronic device may be a projector or a smart headset. Among them, smart head-mounted devices can be augmented reality (Augmented Reality, AR) glasses, virtual reality (Virtual Reality, VR) glasses, etc.

Example 1

In a specific embodiment, the total effective focal length of the optical projection system is eff=5.113mm, and the total system length is 33mm.

Referring to Figure 1, the first lens 1 is a plastic aspheric lens, the first surface S1 of the first lens 1 is a convex surface, and the second surface S2 is a concave surface; the second lens 2 and the third lens 3 are both glass lenses. The second lens 2 and the third lens 3 are double cemented lenses. The first surface S3 of the second lens 2 is a concave surface and the second surface S4 is a concave surface; the first surface S4 of the third lens 3 is a convex surface and the second surface S5 The fourth lens 4 and the fifth lens 5 are both glass lenses, the fourth lens 4 and the fifth lens 5 are double cemented lenses, the first surface S8 of the fourth lens 4 is a concave surface, and the second surface S9 is Convex surface; the first surface S9 of the fifth lens 5 is a concave surface; the second surface S10 is a convex surface; the sixth lens 6 is a glass aspherical lens, the first surface S11 of the sixth lens 6 is a convex surface, and the second surface S12 The surface is convex.

Among them, the effective focal length f1 of the first lens 1 = -8.645mm; the effective focal length f2 of the second lens 2 = -18.751mm; the effective focal length f3 of the third lens 3 = 9.159mm; the effective focal length f4 of the fourth lens 4 = 11.417 mm; the effective focal length of the fifth lens 5 is f4 = -12.585mm; the effective focal length of the sixth lens 6 is f4 = 10.635mm.

This optical projection system is suitable for the size of 0.2" DMD, the aspect ratio is 16:9, the specific size is 4.6116*2.592mm, the design throw ratio is 1.1, and the max_offset is 160%.

The parameters of each of the above lenses are shown in Table 1:

In this embodiment, the optical projection system meets the design requirements, that is, the optical projection system is suitable for the size of 0.2" DMD, the aspect ratio is 16:9, the specific size is 4.6116*2.592mm, and the optical projection system meets the throw ratio of 1:1 , projection distance 300mm, offset160%, wavelength RGB, TV distortion less than 0.5%, full field of view MTF>0.5@96lp/mm, telecentricity <1°, chromatic aberration <0.5pixel, F# is 1.7.

After measurement, the obtained field-of-view parameters of the above-mentioned optical imaging module are shown in Figures 3 to 5.

Figure 3 shows a modulation transfer function (MTF) diagram of this embodiment. Figure 3 is a diagram of the modulation transfer function of the projection optical system at different image heights. The horizontal axis is the spatial frequency (Spatial Frequency in cycles per mm), and the vertical axis is the OTF modulus (Modulus of the OTF). It can be seen from the figure that the OTF module value of the image can always be maintained above 0.5 in the spatial frequency range of 0mm-93mm. Generally speaking, the closer the OTF module value is to 1, the higher the quality of the image. However, due to the influence of various factors, it does not There is a situation where the OTF module value is 1. Generally, when the OTF module value can be maintained above 0.5, it means that the image has high imaging quality and the picture clarity is excellent. Refer to Figure 3, the MTF value of each field of view is high. At 0.5, it can be seen that the image clarity after imaging by this system will be very good in various fields of view.

As shown in Figure 4, it is a modulation transfer function diagram for each field of view tolerance according to the embodiment of the present application. Referring to Figure 3, the MTF values of each field of view perform very well under normal tolerances.

As shown in FIG. 5 , it is a defocus curve of the optical projection system according to the embodiment of the present application. As shown in Figure 5, the defocus range is >20um@MTF0.4, so the assembly requirements of this optical projection system are also greatly reduced.

Example 2

In a specific embodiment, the total effective focal length of the optical projection system is eff=5.2mm, and the total system length is 35mm.

Referring to Figure 2, the first lens 1 is a plastic aspheric lens, the first surface S1 of the first lens 1 is a convex surface, and the second surface S2 is a concave surface; the second lens 2 and the third lens 3 are both glass lenses. The first surface S3 of the second lens 2 is a concave surface, and the second surface S4 is a concave surface; the first surface S5 of the third lens 3 is a convex surface, and the second surface S6 is a convex surface; the fourth lens 4 and the fifth lens 5 are both It is a glass lens. The fourth lens 4 and the fifth lens 5 are double cemented lenses. The first surface S8 of the fourth lens 4 is a concave surface and the second surface S9 is a convex surface. The first surface S9 of the fifth lens 5 is a concave surface. ; The second surface S10 is a convex surface; the sixth lens 6 is a glass aspherical lens, the first surface S11 of the sixth lens 6 is a convex surface, and the second surface S12 is a convex surface.

In this embodiment, the effective focal length f1 of the first lens 1 = -9.45mm; the effective focal length f2 of the second lens 2 = -20.151mm; the effective focal length f3 of the third lens 3 = 8.01mm; the effective focal length of the fourth lens 4 The focal length f4=10.77mm; the effective focal length f4 of the fifth lens 5=-10.417mm; the effective focal length f4 of the sixth lens 6=7.535mm.

The parameters of each of the above lenses are shown in Table 2:

After measurement, the obtained field-of-view parameters of the above-mentioned optical imaging module are shown in Figures 6 to 7.

Figure 6 shows the modulation transfer function diagram (modulation transfer function, MTF) of this embodiment). Figure 6 is a diagram of the modulation transfer function of the projection optical system at different image heights. The horizontal axis is the spatial frequency (Spatial Frequency in cycles per mm), and the vertical axis is the OTF modulus (Modulus of the OTF). It can be seen from the figure that the OTF module value of the image can always be maintained above 0.55 in the spatial frequency range of 0mm-93mm. Generally speaking, the closer the OTF module value is to 1, the higher the quality of the image. However, due to the influence of various factors, it does not There is a situation where the OTF module value is 1. Generally, when the OTF module value can be maintained above 0.55, it means that the image has high imaging quality and the picture clarity is excellent. Refer to Figure 6, the MTF value of each field of view is high. At 0.55, it can be seen that the image clarity after imaging by this system will be very good in various fields of view.

As shown in Figure 7, it is a defocus curve of the optical projection system according to the embodiment of the present application. As shown in Figure 7, the defocus range is >18um@MTF0.4, so the assembly requirements of this optical projection system are also greatly reduced.

The above embodiments focus on the differences between the various embodiments. As long as the different optimization features between the various embodiments are not inconsistent, they can be combined to form a better embodiment. Considering the simplicity of the writing, they will not be discussed here. Repeat.

Although some specific embodiments of the present application have been described in detail through examples, those skilled in the art will understand that the above examples are for illustration only and are not intended to limit the scope of the present application. Those skilled in the art will understand that the above embodiments can be modified without departing from the scope and spirit of the application. The scope of the application is defined by the appended claims.

Claims

An optical projection system, characterized in that it includes: a first lens (1), a second lens (2), a third lens (3), a fourth lens (4), and a fifth lens in order from the magnification side to the reduction side. (5) and the sixth lens (6), the effective focal length of the optical projection system is: 4.5mm<eff<6.7mm, the optical projection system satisfies the following relationship: 3.5<TL/D<5, where TL is the optical The total optical length of the projection system, D is the maximum lens diameter in the optical projection system.
The optical projection system according to claim 1, characterized in that, from the magnification side to the reduction side, the optical power order of the optical projection system is: negative, negative, positive/positive, negative, positive.
The optical projection system according to claim 1, characterized in that the fourth lens (4) and the fifth lens (5) are cemented to form a first cemented lens, and the second lens (2) and the The third lens (3) is glued and connected to form a second glued lens.
The optical projection system according to claim 1, characterized in that the distance between the second lens (2) and the third lens (3) is d1, and the distance between the first lens (1) and the sixth lens (3) is d1. The distance between lenses (6) is L, where: d1/L<0.2.
The optical projection system according to claim 1, characterized in that the distance between the first lens (1) and the sixth lens (6) is L, and the distance between the third lens (3) and the fourth lens (6) is L. The distance between lenses (4) is d2, where d2/L<0.5.
The optical projection system according to claim 1, characterized in that an aperture (7) is provided between the third lens (3) and the fourth lens (4), and the third lens (3) The distance between the fourth lens (4) and the aperture (7) is d3, and the distance between the fourth lens (4) and the aperture (7) is d4, where 0.7<d3/d4<1.3.
The optical projection system according to claim 1, characterized in that the first lens (1) has a first surface facing away from the second lens (2), and the first lens (1) has a surface parallel to the second lens (2). (2) For adjacent second surfaces, the radius of the first surface is D1 and the radius of the second surface is D2, where 2≤D1/D2≤5.
The optical projection system according to claim 1, characterized in that the optical projection system satisfies the following relationships: -10mm<f1<-6.6mm, -20mm<f2<-16.7mm, 6mm<f3<11mm, 9mm< f4<13mm, -15mm<f5<-9mm, 7mm<f6<12.6mm;

Wherein, f1 is the effective focal length of the first lens (1), f2 is the effective focal length of the second lens (2), f3 is the effective focal length of the third lens (3), and f4 is the fourth lens (3). The effective focal length of the lens (4), f5 is the effective focal length of the fifth lens (5), and f6 is the effective focal length of the sixth lens (6).
The optical projection system according to claim 1, characterized in that:

The first surface of the first lens (1) is a convex surface, and the second surface of the first lens (1) is a concave surface;

The second surface of the second lens (2) is a concave surface;

The first surface and the second surface of the third lens (3) are both convex surfaces;

The first surface of the fourth lens (4) is a concave surface or a flat surface, and the second surface of the fourth lens (4) is a convex surface;

The first surface of the fifth lens (5) is a concave surface, and the second surface of the fifth lens (5) is a convex surface;

The first surface and the second surface of the sixth lens (6) are both convex surfaces;

Wherein, the first surface of each lens is disposed closer to the magnifying side than the second surface thereof.
An electronic device, characterized in that the electronic device includes the optical projection system according to any one of claims 1-9.