CN219872085U - Projection optical module, projection display system and wearable equipment - Google Patents

Abstract

The embodiment of the utility model discloses a projection optical module, a projection display system and wearable equipment; wherein, projection optical module includes: a beam-splitting prism, a polarizing element, a lens group, a fourth lens, and a fifth lens; the beam-splitting prism comprises a light incident surface, a light emergent surface, a second transmission surface and a first transmission surface; the polarizing element is positioned at one side of the light incident surface; the lens group is positioned at one side of the light-emitting surface and comprises a first lens, a second lens and a third lens which are sequentially arranged; the fourth lens is positioned at one side of the second transmission surface, a phase retarder is arranged between the fourth lens and the second transmission surface, and the fifth lens is positioned at one side of the first transmission surface; and a reflecting film is arranged on one side of the fourth lens, which is far away from the second transmission surface. The projection optical module provided by the embodiment of the utility model has the imaging effect of higher resolution under the design of small volume.

Description

Projection optical modules, projection display systems and wearable devices

Technical field

This application belongs to the field of optical projection technology. Specifically, this application relates to a projection optical module, a projection display system and a wearable device.

Background technique

Nowadays, with the development of computer technology, various smart wearable devices have emerged. For example, augmented reality devices (AR, Augmented ReaHity), virtual reality devices (VR, VirtuaH ReaHity), mediated reality devices (MR, Mediated ReaHity) and XR devices are gaining more and more attention and favor from consumers. Taking AR devices as an example, the current main forms of AR devices include AR glasses or AR helmets, both of which are head-mounted devices. However, AR devices are generally heavier, which is contrary to the first performance requirement of AR devices, which is wearable comfort, including miniaturization and lightweight. Therefore, in order to improve the user experience, the lightweight design of AR has become an important development direction of AR glasses.

Contents of the invention

The purpose of this application is to provide a new technical solution for a projection optical module, a projection display system and a wearable device, which solves the problem that the projection optical module in the existing wearable device cannot achieve both high performance and high performance while being small in size and thin. Resolution imaging issues.

According to a first aspect of the present application, a projection optical module is provided, which includes:

A dichroic prism, which includes a light incident surface and a light exit surface, as well as a second transmission surface and a first transmission surface;

A polarizing element located on one side of the light incident surface;

A lens group, the lens group is located on one side of the light-emitting surface, and the lens group includes a first lens, a second lens and a third lens arranged in sequence;

A fourth lens and a fifth lens. The fourth lens is located on one side of the second transmission surface. A phase retarder is provided between the fourth lens and the second transmission surface. The fifth lens is located on one side of the second transmission surface. One side of the first transmission surface;

A reflective film is provided on the side of the fourth lens away from the second transmission surface.

Optionally, the effective focal length EFFL of the projection optical module is: 6mm<EFFL<10mm.

Optionally, the first lens, the second lens and the third lens are arranged along the same optical axis;

Wherein, the first lens and the second lens are cemented with each other to form a cemented lens group, and the cemented lens group is located between the dichroic prism and the third lens.

Optionally, the light incident surface (101) and the light exit surface (102) are arranged adjacently.

Optionally, the light incident surface (101) and the light exit surface (102) are arranged oppositely.

Optionally, the polarizing element is used to receive the projection light and can transmit the first polarized light to the dichroic prism, and the dichroic prism is used to modulate the light into the second polarized light and transmit it to the phase Retarder, the phase retarder transmits light to the fourth lens, the reflective film of the fourth lens reflects the light to the phase retarder and then enters the dichroic prism, and the projection light passes through it twice The phase retarder turns into a first polarized light, which is then reflected by the dichroic prism and sequentially passes through the first lens, the second lens and the third lens to reach the exit pupil position.

According to the second aspect of the present application, a projection display system is also provided. The projection display system includes:

A light source module, the light source module is used to generate projection light, and the projection light includes light of multiple different colors;

The projection optical module as described in the first aspect, the projection optical module is located on the optical transmission path of the light source module; and

An imaging chip is located on the side of the fifth lens away from the dichroic prism.

Optionally, the projection display system further includes a field lens located between the light source module and the projection optical module;

Optionally, the field lens is a lens with positive optical power, two surfaces of the field lens are convex surfaces, and the field lens is used to collect the projection light to the projection optical module;

Optionally, the polarizing element is located between the field lens and the dichroic prism, and the polarizing element is provided on the light incident surface.

Optionally, the projection display system further includes a light uniforming element located between the light source module and the projection optical module; wherein the light uniforming element is a plastic compound eye lens.

Optionally, the light source module includes a light source and a collimating lens group, and the collimating lens group is located on the optical transmission path of the light source;

Wherein, the light source includes a plurality of light-emitting chips of different colors, the plurality of light-emitting chips are arranged to form a target array, and the center of the target array is located on the optical axis of the collimating lens group;

The projection light emitted through the collimating lens group can be directly subjected to uniform light processing.

Optionally, the collimating lens group includes a first collimating lens and a second collimating lens arranged at intervals along the same optical axis; wherein the second collimating lens includes at least one aspherical surface;

The optical power of the first collimating lens and the second collimating lens is positive;

The first collimating lens and the second collimating lens are used to collimate the projection light into parallel light and then emit it.

According to a third aspect of the present application, a wearable device is also provided. The wearable devices include:

housing; and

The projection display system as described in the second aspect.

The beneficial effects of this application are:

The projection optical module proposed in the embodiment of the present application is a miniaturized and lightweight LCOS projection imaging optical structure. It can achieve better imaging quality in a small size, and the design of the entire optical path is simple. The projection optical module can be matched with a single multi-color light source, and can reduce the number of optical devices used, further miniaturizing and lightweighting wearable devices, and saving costs.

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 the drawings

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

Figure 1 is a schematic structural diagram of a projection optical module provided by an embodiment of the present application;

Figure 2 is one of the structural schematic diagrams of the projection display system provided by the embodiment of the present application;

Figure 3 is the second structural schematic diagram of the projection display system provided by the embodiment of the present application;

Figure 4 is a schematic structural diagram of a light source of the projection display system provided by an embodiment of the present application;

Figure 5 is an MTF diagram in each field of view of the projection display system provided by the embodiment of the present application;

Figure 6 is a distortion diagram in each field of view of the projection display system provided by the embodiment of the present application.

Explanation of reference symbols:

1. Beam splitting prism; 101. Light incident surface; 102. Light exit surface; 103. Second transmission surface; 104. First transmission surface; 2. Polarizing element; 3. First lens; 4. Second lens; 5. Three lenses; 6. Fifth lens; 7. Fourth lens; 8. Phase retarder; 9. Beam splitting film; 10. Imaging chip; 11. Field lens; 12. Light uniformity element; 13. Light source; 131. Light-emitting chip ; 14. The first collimating lens; 15. The second collimating lens.

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, methods and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, such techniques, methods and devices 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.

The projection optical module, projection display system and wearable device provided by the embodiment of the present application will be described in detail below with reference to the accompanying drawings 1 to 6 .

The projection optical module provided according to the embodiment of the present application can be applied in a projection display system. The projection optical module and the light source module are matched to form a projection display system. The projection display system can be used in, for example, AR head-mounted display devices. Wherein, the projection optical module serves as the imaging light path part of the projection display module, and can project the projection light for imaging emitted by the light source module (as the illumination light path part) into an image, so that the user can see Clear picture.

Refer to Figures 1 to 3 for the projection optical module provided by the embodiment of the present application. The projection optical module includes a dichroic prism 1, a polarizing element 2, a lens group, a fourth lens 7 and a fifth lens 6. Wherein, the dichroic prism 1 includes a light incident surface 101 and a light exit surface 102, as well as a second transmission surface 103 and a first transmission surface 104. The polarizing element 2 is located on one side of the light incident surface 101 . The lens group is located on one side of the light-emitting surface 102. The lens group includes a first lens 3, a second lens 4 and a third lens 5 arranged in sequence; the fourth lens 7 is located on the second transmission surface. 103, a phase retarder 8 is provided between the fourth lens 7 and the second transmission surface 103, the fifth lens 6 is located on one side of the first transmission surface 104, and the fourth lens 6 is located on one side of the first transmission surface 104. A reflective film is provided on the side of the lens 7 away from the second transmission surface 103 . The effective focal length EFFL of the projection optical module is: 6mm<EFFL<10mm.

According to the above-mentioned embodiments of the present application, the projection optical module may include five lenses, namely the above-mentioned first lens 3, second lens 4, third lens 5, fourth lens 7 and fifth lens 6. The entire The effective focal length of the projection optical module is designed to be between 6mm and 10mm. It achieves a miniaturized design while taking into account high-resolution imaging quality. Among them, five lenses are arranged on the peripheral sides of the dichroic prism 1, for example, on three sides. The entire module has the characteristics of small size.

As a preferred embodiment of the present application, the projection optical module includes five glass lenses, and the effective focal length of the projection optical module is 6 mm to 9.7 mm.

The fifth lens 6 is located on one side of the first transmission surface 104 of the dichroic prism 1 . Specifically, the fifth lens 6 can be placed between the dichroic prism 1 and the LCOS image plane (the imaging chip 10 shown in FIGS. 1 to 3 ), and the fifth lens 6 can play the role of Correcting distortion and spherical aberration.

According to the projection optical module provided in the above embodiments of the present application, when it is applied to a projection display system, see Figures 2 and 3, for example, the projection light emitted by the light source module can pass through the incident light of the dichroic prism 1 One side of the surface 101 enters the dichroic prism 1 through the polarizing element 2, and the dichroic prism 1 will reflect the available projection light into the projection optical module. When this part of the available projection light is reflected from the projection optical module back to the dichroic prism 1, it will carry image information, and the polarization direction of this part of the projection light will rotate 90°, so that it can pass through the dichroic prism 1 and The phase retarder 8 (for example, a quarter wave plate) and the fourth lens 7 are incident from the second transmission surface 103 thereof. The fourth lens 7 can reflect this part of the projection light. After this part of the projection light passes through the phase retarder 8 twice, the polarization direction of the projection light is rotated 90°, and then the projection light passes through the dichroic prism. After reflection, it passes through the first lens 3, the second lens 4 and the third lens 5 in order to reach the exit pupil position, and the end user can see a high-definition imaging picture.

The projection optical module provided by the above-mentioned implementation of the present application is designed with a folded optical path, so the formed optical framework can achieve a larger FOV imaging design, which can improve the user's immersive experience. Moreover, the design based on folded optical path can also improve the optical performance of the module.

According to the projection optical module provided by the above embodiments of the present application, the MTF value in each field of view is high, that is, the image clarity after imaging by the projection optical module in each field of view is very good. Moreover, the TV distortion after imaging by the projection optical module in each field of view will be relatively small, which can fully meet the distortion requirements of the human eye.

The projection optical module proposed in the embodiment of this application is a miniaturized and lightweight LCOS projection optical module. It has a small size and can have better imaging quality, and the entire optical path design is simple; the entire projection optical module The group can be matched with a single multi-color light source, and can reduce the number of optical devices used, further miniaturizing and lightweighting wearable devices, and saving costs.

According to the projection optical module provided by the above embodiments of the present application, the exit pupil size of the projection optical module is 3.3 mm to 4 mm, the F number is 1.8 to 2.4, and the field of view angle FOV ≤ 30°. Compared with optical structures of the same volume, this can achieve good imaging effects and users can see clear images.

In some examples of this application, referring to Figures 1 to 3, the first lens 3, the second lens 4 and the third lens 5 are arranged along the same optical axis; wherein the first lens 3 and the third lens 5 are arranged along the same optical axis; The second lenses 4 are cemented together to form a cemented lens group, and the cemented lens group is located between the dichroic prism 1 and the third lens 5 .

According to the projection optical module provided by the embodiment of the present application, a lens group is provided on one side of the light exit surface 102 of the dichroic prism 1. The lens group may include the three lenses in the above example, and the three lenses are along the Same optical axis setting. Among them, the two lenses close to the light exit surface 102 of the dichroic prism 1, that is, the first lens 3 and the second lens 4 are double glued parts, and they are glued together. This design can reduce the size of the entire projection optical module. The color difference will help improve the quality of the imaging picture.

According to the above example of this application, the third lens 5 is adjacent to and spaced apart from the cemented lens group. The third lens 5 can collect available projection light to reduce the lens aperture, which is beneficial to realizing a short focus design.

Optionally, the first lens 3 and the light exit surface 102 are arranged adjacent to each other, and the effective focal length EFFL ₁ of the first lens 3 is: -8mm<EFFL ₁ <-6mm; the second lens 4 The effective focal length of EFFL ₂ is: 8mm＜EFFL ₂ ＜13mm.

Optionally, the first lens 3 and the second lens 4 form a cemented lens group, and the thickness H ₁₂ of the cemented lens group is: 1 mm < H ₁₂ < 2 mm.

As a preferred method of this application, the effective focal length EFFL ₁ of the first lens 3 is: -8mm <EFFL ₁ <-6.4mm, and the effective focal length EFFL ₂ of the second lens 4 is: 8mm <EFFL ₂ < 12.1mm. The thickness of the cemented lens group formed by the first lens 3 and the fourth lens 4 is 1.2mm<H ₁₂ <2.0mm. The cemented lens formed in this way has the characteristics of short focus and small thickness. It is beneficial to realize the short-throw design of the entire projection optical module, and can realize the miniaturization and lightweight of the projection optical module, and on this basis, the imaging quality can be taken into consideration.

Optionally, the first lens 3 includes at least one concave surface, and the surface of the second lens 4 facing away from the first lens 3 is a convex surface.

Wherein, the Abbe number of the first lens 3 is v ₁ , the Abbe number of the second lens 4 is v ₂ , and the Abbe numbers of the first lens 3 and the second lens 4 satisfy: v ₂ ≥2v ₁ . Through a reasonable combination of Abbe numbers, dispersion can be reduced to improve image quality.

Optionally, the effective focal length EFFL ₃ of the third lens 5 is: 12mm<EFFL ₃ <19mm.

As a preferred method of this application, the effective focal length EFFL ₃ of the third lens 5 is: 12mm<EFFL ₃ <18.3mm.

The reasonable matching of the effective focal lengths of the three lenses on the light-emitting surface 102 of the dichroic prism 1 can realize the short-throw design of the entire projection optical module and take into account the quality requirements of imaging.

Optionally, the thickness H ₃ of the third lens 5 is: 0.4 mm < H ₃ < 0.8 mm; both surfaces of the third lens 5 are convex surfaces.

The third lens 5 can be designed to be thinner, which is beneficial to reducing the lateral size of the entire projection optical module and also reducing the weight.

In the projection optical module provided by the embodiment of the present application, a fourth lens 7 is provided on one side of the second transmission surface 103 of the dichroic prism 1 . The fourth lens 7 is a reflecting mirror.

In some examples of this application, the effective focal length EFFL ₄ of the fourth lens 7 is: 5mm<EFFL ₄ <9mm.

Optionally, the thickness H ₄ of the fourth lens 7 is: 0.6 mm < H ₄ < 2 mm; the fourth lens 7 includes at least one convex surface.

In the projection optical module provided by the embodiment of the present application, a reflector, that is, the fourth lens 7 is provided on one side of the second transmission surface 103 of the dichroic prism 1. At the same time, between the fourth lens 7 and the A phase retarder 8 is disposed between the second transmission surfaces 103 of the dichroic prism 1 . The phase retarder 8 here is, for example, a quarter-wave plate.

The quarter-wave plate may be fixedly disposed on the second transmission surface 103 of the dichroic prism 1 . According to the foregoing description of the optical propagation path, the available projection light carrying image information will pass through the quarter-wave plate twice, and then be reflected back to the dichroic prism 1 by the fourth lens 7 . It should be emphasized that when the projection light passes through the quarter-wave plate on the second transmission surface 103 twice, the polarization direction of the projection light will rotate 90° again so that it passes through the fourth lens 7 After the reflected projection light enters the dichroic prism 1, it will continue to vibrate along the initial polarization direction (such as the first polarization state), and then emerge through the light exit surface 102 of the dichroic prism 1, and pass through the first polarization state in turn. The lens 3, the second lens 4 and the third lens 5 then enter the human eye and form an image.

In the projection optical module provided by the embodiment of the present application, a fifth lens 6 is provided on one side of the first transmission surface 104 of the dichroic prism 1 .

In some examples of this application, the effective focal length EFFL ₅ of the fifth lens 6 is: 16mm<EFFL ₅ <23mm.

Optionally, the thickness H ₅ of the fifth lens 6 is: 0.5mm<H ₄ <1mm;

The surface of the fifth lens 6 close to the second transmission surface 103 is a convex surface, and the surface of the fifth lens 6 away from the second transmission surface 103 is a concave surface.

As a preferred method of this application, the effective focal length EFFL ₅ of the fifth lens 6 is: 16mm<EFFL ₅ <22.4mm, and the thickness _H5 of the fifth lens 6 is: 0.53mm<H ₄ <0.95mm .

According to the above example of this application, the fifth lens 6 is located on one side of the first transmission surface 104 of the dichroic prism 1 , and the fifth lens 6 can be designed to be located between the dichroic prism 1 and the imaging chip 10 At a suitable position, the fifth lens 6 is used to correct distortion and spherical aberration.

For example, the distortion values of the projection optical module in each field of view are less than 1.1%, which indicates that the imaging quality is good.

In some examples of this application, referring to Figures 1 and 2, the dichroic prism 1 includes a first prism and a second prism connected to each other, and a dichroic film 9 is provided between the first prism and the second prism. .

The dichroic film 9 can transmit a part of the projection light and reflect a part of the projection light. The light transmittance of the light splitting film 9 (PBS film) can be adjusted as needed.

Specifically, the projection optical module is provided with a dichroic film 9 , a phase retarder 8 and a polarizing element 2 so that a folded optical path can be formed. Wherein, the dichroic film 9 (PBS film) is between the first prism and the second prism, and the polarizing element 2 is, for example, a polarizing film (POL film) provided on the light incident surface 101 of the dichroic prism 1, The phase retarder 8 is, for example, a quarter-wave plate (QWP film), and the quarter-wave plate is mounted on the second transmission surface 103 of the dichroic prism 1 . Wherein, the polarization direction of the polarizing element 2 is, for example, to transmit the first polarized light (S light).

Wherein, the phase retarder 8 includes a quarter wave plate. The fast axis of the phase retarder 8 and the edge of the dichroic prism 1 form a 45-degree arrangement.

According to the above-mentioned projection optical module provided by the embodiment of the present application, its optical path propagation path is as follows:

The polarizing element 2 is used to receive the projection light and can transmit the first polarized light to the dichroic prism 1; the dichroic prism 1 is used to modulate the light into the second polarized light and transmit it to the phase delay 8; the phase retarder 8 transmits light to the fourth lens 7, the fourth lens 7 reflects the light to the phase retarder 8 and then enters the dichroic prism 1, and the projection light is After passing through the phase retarder 8 once, it becomes the first polarized light, and then is reflected by the dichroic prism 1 before exiting and passing through the first lens 3, the second lens 4 and the third lens in sequence. 5 reaches the exit pupil position and finally forms an image in the human eye.

According to the projection optical module provided by the embodiment of the present application, the dichroic prism 1 includes a light incident surface 101, a light exit surface 102, a second transmission surface 103 and a first transmission surface 104. Depending on the position of the incident light source, the incident light The layout positions and directions of the surface 101 , the light-emitting surface 102 , the second transmission surface 103 and the first transmission surface 104 are also different.

For example, referring to FIGS. 1 and 2 , the light incident surface 101 and the light exit surface 102 are arranged oppositely, and the second transmission surface 103 and the first transmission surface 104 are arranged oppositely.

For another example, see FIG. 3 , the light incident surface 101 and the light exit surface 102 are arranged adjacently, and the second transmission surface 103 and the first transmission surface 104 are arranged adjacently.

Among them, FIG. 3 shows an optical architecture modification of the projection optical module shown in FIGS. 1 and 2 .

In specific applications, the first lens 3 and the second lens 3 can be configured according to the different positions and directions of the light incident surface 101 and the light exit surface 102 of the dichroic prism 1, as well as the second transmission surface 103 and the light exit surface 102. The relative positions of the lens 4, the third lens 5, the fourth lens 7 and the fifth lens 6 can be adjusted and transformed.

Referring to Figure 3, the first lens 3 and the second lens 4 still form a cemented lens, and the third lens 5 and the cemented lens are adjacent and spaced apart. After the lens 4 and the third lens 5 form a lens group, they are located on one side of the light exit surface 102 of the dichroic prism 1, and the fourth lens 7 is located on one side of the second transmission surface 103 of the dichroic prism 1. The fifth lens 6 is located on one side of the first transmission surface 104 of the dichroic prism 1 . However, the difference from the optical architecture shown in Figures 1 and 2 is that the light incident surface 101 and the light exit surface 102 of the dichroic prism 1, as well as the second transmission surface 103 and the first transmission surface 104 are no longer Relative settings, but adjacent settings.

According to another embodiment of the present application, a projection display system is also provided. See FIG. 2 . The projection display system includes: a light source module, the above-mentioned projection optical module and the imaging chip 10 . Wherein, the light source module is used to generate projection light, and the projection light includes light of multiple different colors; the projection optical module is located on the optical transmission path of the light source module. The imaging chip 10 is located on the side of the fifth lens 6 away from the dichroic prism 1 .

The projection display system provided according to the above embodiments of the present application includes a light source module. See Figure 2. The light source module is an illumination light path design and belongs to the illumination light path part of the projection display system.

Wherein, the light source module is, for example, a multi-color light source. The light source module can emit projection light for imaging, and the projection light can include light of multiple different colors, such as green light, red light, and blue light.

Of course, the light source modules in the embodiments of the present application include, but are not limited to, being able to emit light of these three colors. They can also emit light of other colors, as long as they can emit visible light.

In some examples of the present application, referring to FIG. 2 , the projection display system further includes a field lens 11 located between the light source module and the projection optical module. The field lens 11 is a lens with positive optical power, and two surfaces of the field lens 11 are convex surfaces. The field lens 11 is used to collect the projection light to the projection optical module. The polarizing element 2 is located between the field lens 11 and the dichroic prism 1 , and is provided on the light incident surface 101 .

In the projection display system provided by the embodiment of the present application, a field lens 11 is introduced and disposed on the light incident side of the projection optical module, that is, between the light source module and the projection optical module. At a suitable position between the two, the optical power of the field lens 11 is positive, and the field lens 11 can be used to collect the projection light to the projection optical module, which is beneficial to improving the light efficiency.

In some examples of this application, referring to Figure 2, the projection display system further includes a light uniforming element 12, which is located between the light source module and the field lens 11; wherein the uniform light element 12 is located between the light source module and the field lens 11; The optical element 12 is a plastic compound eye lens.

Among them, the uniform light element 12 can perform uniform light processing on the projection light emitted by the light source module, which is beneficial to improving the final imaging quality.

Among them, the light uniforming element 12 can be a fly-eye lens.

The material of the compound eye lens can be designed as plastic material, for example. This lighter weight helps reduce the weight of the entire device and improves the user's wearing comfort.

In some examples of this application, the light source module includes a light source 13 and a collimating lens group, and the collimating lens group is located on the optical transmission path of the light source 13; wherein the light source 13 includes a plurality of different Colored light-emitting chips 131, a plurality of the light-emitting chips 131 are arranged to form a target array, the center of the target array is located on the optical axis of the collimating lens group; the projection light emitted through the collimating lens group can Directly perform homogenization processing.

According to the above examples of this application, a target array can be formed by arranging the light-emitting chips 131 of different colors, thus forming a multi-color light source, which is the above-mentioned light source 13 . This design allows only one light source 13 to emit projection light containing, for example, at least three different colors (eg, R/G/B). Moreover, the projection light emitted by the light source 13 can be collimated by a single collimating lens group on a single optical channel, and after being collimated by the collimating lens group, the light spots of the various colors of light are The uniformity is good and can fully meet the viewing needs of the human eye.

That is to say, the above-mentioned light source 13 adopts an all-in-one light source, for example, the RGB light source is integrated on an LED. In the illumination light path part, the collimated and uniform light path only needs to be provided with a single channel, which greatly reduces the size of the other two directions. This greatly reduces the overall thickness and volume of the light source module. When this light source module is applied to a projection display system, it will help achieve thinning and miniaturization of related equipment.

Referring to Figure 4, when forming the light source 13, the center of the target array formed by the plurality of light-emitting chips 131 is designed to be located on the optical axis of the collimating lens group, that is, the center of the target array and the The center of the collimating lens group is coaxial. Under this design, after the collimating lens group collimates the light of corresponding wavelengths emitted by each light-emitting chip 131, the uniformity of light of various colors is better, thereby improving the user's viewing experience.

The light source module proposed in the above embodiment of the present application can be used as an illumination light path in a projection display system. A single light source 13 can integrate multiple light-emitting chips 131 of different colors, and only one collimating lens group can be used to illuminate a variety of Light of different colors is collimated and the collimation effect is better. There is no need to set up a beam splitter element in the entire optical path design to combine the light, that is, it can directly enter the uniform light. The light source module can achieve small-volume illumination. Furthermore, since a single light source 13 has multiple light-emitting chips (light-emitting surfaces), it can also achieve high-brightness lighting.

In the above-mentioned example of this application, when forming a single light source 13, multiple light-emitting chips 131 are arranged symmetrically around the optical axis of the collimating lens group as the central axis to form a target array of the light source 13. The center of is located on the optical axis of the collimating lens group. On this basis, the corresponding light emitted by each of the light-emitting chips 131 can be collimated close to the optical axis through a collimating lens group, and since the multiple light-emitting chips 131 are symmetrically arranged, the uniformity can be compensated for each other during collimation. , so that the uniformity of the collimated light of each color is better, which can fully meet the viewing needs of the human eye.

For example, referring to Figure 4, there are two green light chips G, and the two green light chips G form a set of diagonally symmetrical arrangements; the red light chip R and the blue light chip B are respectively set to one , and the red light chip R and the blue light chip B form another group of diagonally symmetrical arrangements.

The above-mentioned arrangement of multiple light-emitting chips is simple and easy to implement, and a collimating lens group can be used to collimate the red, green, and blue light emitted by the three light-emitting chips. The uniformity of each light after collimation OK, and no need to combine photos. At the same time, due to the design of a single light source 13 with multiple light-emitting chips, high-brightness lighting can also be achieved.

It needs to be emphasized that when the projection screen has high requirements for a certain color, the light-emitting chip corresponding to the light of that color can be appropriately added and the light-emitting chip is set to be diagonally symmetrical. For example, there are two green light chips G in the above example. On this basis, two green light chips G and a single blue light chip B and a single red light chip R can form two groups of diagonally symmetrical distribution (or centrally symmetrical arrangement) around the optical axis of a collimating lens group, so that each The uniformity of the color light after collimation is better, which can better improve the visual experience of users watching the projection screen.

In some examples of this application, referring to Figure 2, the collimating lens group includes a first collimating lens 14 and a second collimating lens 15 arranged along the same optical axis and spaced apart; wherein, the second collimating lens 15 includes at least one aspherical surface;

The optical power of the first collimating lens 14 and the second collimating lens 15 is positive;

The first collimating lens 14 and the second collimating lens 15 are used to collimate the projection light into parallel light and then emit it.

The projection light emitted by the light source module is collimated by the collimating lens group and then passes through the uniform light element 12. After the uniform light element 12 uniformly diffuses the collimated light, the projection light passes through The field lens 11 then enters the polarizing element 2. The polarizing element 2 transmits the first polarized light to the dichroic prism 1. The dichroic prism 1 modulates the incident light into the second polarization state. The light is transmitted to the phase retarder 8, then reflected to the fourth lens 7, reflected to the phase retarder 8 through the fourth lens 7, and then to the dichroic prism 1. During the above process, the light is projected to two After passing through the phase retarder 8 for the first time, the projection light becomes the first polarized light, and is reflected by the dichroic prism 1 and passes through the first lens 3, the second lens 4 and the third lens in turn. 5 reaches the exit pupil.

In a specific example of this application, referring to Figures 1 and 2, the projection display system includes: a light source module, a projection optical module and an imaging chip 10; wherein the projection optical module includes five lenses, respectively. They are the first lens 3, the second lens 4, the third lens 5, the fourth lens 7 and the fifth lens 6. The light source module includes a light source 13, which is a four-in-one light source. The light source module is located on the light incident surface 101 side of the dichroic prism 1 . The lens group composed of the first lens 3, the second lens 4 and the third lens 5 is located on the light exit surface 102 side of the dichroic prism 1, and the fourth lens 7 is located on the second transmission side of the dichroic prism 1. On the surface 103 side, the fifth lens 6 and the imaging chip 10 are located on the first transmission surface 104 side of the dichroic prism 1 .

Referring to Table 1 below, the optical parameters of the projection display system provided by the above specific examples are shown.

Table 1

performance parameter Entrance pupil diameter 3.3mm EFFL 7.0mm LCOS size 2.462*2.462mm wavelength RGB TV distortion <1.1% Full field of view MTF ＞0.5@132lp/mm telecentric <1.5° FOV 28°

In order to effectively improve the optical performance of the projection display system, using the optical structure shown in Figure 1 and Figure 2, the specific parameters of the designed projection display system are as follows:

The effective focal length of the projection display system is EFFL=7.03mm, and the total length of the system is 8mm*8mm.

The imaging optical path part of the projection display system includes five spherical lenses made of glass material.

The surface S6 of the first lens 3 close to the dichroic prism 1 is concave. The surface S3 of the second lens 4 close to the third lens 5 is a flat surface, and the surface S4 of the second lens 4 away from the third lens 5 is a convex surface. The two surfaces S1 and S2 of the third lens 5 are convex surfaces. The surface S8 of the fourth lens 7 away from the dichroic prism 1 is a convex surface. The surface S11 of the fifth lens 6 close to the dichroic prism 1 is a convex surface, and the surface S10 away from the dichroic prism 1 is a concave surface.

Table 2

The performance achieved is as follows:

Referring to Figure 5, the MTF value of the projection optical system in each field of view is higher than 0.55, and the image clarity formed by the system in each field of view will be very good. Moreover, because it is made of all-glass material, the temperature resistance of the entire system is also very good.

Referring to Figure 6, the distortion value of the projection optical system in each field of view is less than 1.1%. The TV distortion after imaging by the system in each field of view will also be small, which can fully meet the distortion requirements of the human eye.

On the other hand, an embodiment of the present application also provides a wearable device. The wearable device includes a housing and a projection display system as described above.

The above-mentioned wearable devices are, for example, AR smart glasses or AR smart helmets.

The specific implementation of the projection display system and the wearable device according to the embodiment of the present application can refer to the above-mentioned light source module embodiment. Therefore, it has at least all the beneficial effects brought by the technical solutions of the above-mentioned embodiments, and will not be detailed here. Repeat.

Although some specific embodiments of the present application have been described in detail through examples, those skilled in the art should 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 (10)

1. A projection optical module, characterized by comprising: Beam splitting prism (1), which includes a light incident surface (101) and a light exit surface (102), as well as a second transmission surface (103) and a first transmission surface (104); Polarizing element (2), the polarizing element (2) is located on one side of the light incident surface (101); A lens group, the lens group is located on one side of the light exit surface (102), the lens group includes a first lens (3), a second lens (4) and a third lens (5) arranged in sequence; The fourth lens (7) and the fifth lens (6), the fourth lens (7) is located on one side of the second transmission surface (103), the fourth lens (7) and the second transmission surface A phase retarder (8) is provided between the surfaces (103), and the fifth lens (6) is located on one side of the first transmission surface (104); A reflective film is provided on the side of the fourth lens (7) away from the second transmission surface (103). 2. The projection optical module according to claim 1, characterized in that the first lens (3), the second lens (4) and the third lens (5) are arranged along the same optical axis; Wherein, the first lens (3) and the second lens (4) are cemented with each other to form a cemented lens group, and the cemented lens group is located between the dichroic prism (1) and the third lens (5). between. 3. The projection optical module according to claim 1, wherein the effective focal length EFFL of the projection optical module is: 6mm<EFFL<10mm. 4. The projection optical module according to claim 1, characterized in that the light incident surface (101) and the light exit surface (102) are arranged adjacent to or opposite to each other. 5. The projection optical module according to claim 1, characterized in that the effective focal length EFFL ₄ of the fourth lens (7) is: 5mm<EFFL ₄ <9mm. 6. The projection optical module according to claim 1, characterized in that the effective focal length EFFL ₅ of the fifth lens (6) is: 16mm<EFFL ₅ <23mm. 7. A projection display system, characterized by comprising: A light source module, the light source module is used to generate projection light, and the projection light includes light of multiple different colors; The projection optical module according to any one of claims 1 to 6, which is located on the optical transmission path of the light source module; and Imaging chip (10), the imaging chip (10) is located on the side of the fifth lens (6) away from the dichroic prism (1). 8. The projection display system according to claim 7, characterized in that the light source module includes a light source (13) and a collimating lens group, and the collimating lens group is located in the optical transmission path of the light source (13). superior; Wherein, the light source (13) includes a plurality of light-emitting chips (131) of different colors. The plurality of light-emitting chips (131) are arranged to form a target array, and the center of the target array is located on the optical axis of the collimating lens group. superior. 9. The projection display system according to claim 7, characterized in that the projection display system further includes a light uniformity element (12), the light uniformity element (12) is located between the light source module and the projection optical system. between modules. 10. A wearable device, characterized by comprising: housing; and The projection display system according to any one of claims 7-9.