Projection system, near-eye display device and method for preparing optical assembly

Abstract

Disclosed are a method for preparing a projection system, a near-eye display device, and an optical component. The projection system includes: a light source; an optical component, including a light homogenizing element, a prism carrier, and a polarization beam splitter film, wherein the light homogenizing element is located on the projection path of the light source and is provided with an optical axis along the projection path, the light homogenizing element has a first end face, a second end face, and an extension corresponding to the light source; the prism carrier has a light incident surface corresponding to the light homogenizing element, the polarization beam splitter film is fitly sandwiched between the second end face of the light homogenizing element and the light incident surface of the prism carrier, the light homogenizing element, the prism carrier, and the polarization beam splitter film are assembled together to have an integrated structure; a display chip corresponding to the optical component; and a projection lens group located on the light exit path of the optical component. The optical component in the projection system has an integrated structure to reduce the complexity of its system design.

Description

Technical Field

[0001] The present application relates to the field of near-eye display optical technology, and in particular to a projection system for a near-eye display device, a near-eye display device, and a method for preparing optical components in the projection system. Background Art

[0002] In recent years, near-eye display devices such as virtual reality (VR) and augmented reality (AR) have created unique sensory experiences for humans. Near-eye display devices belong to micro-projection devices, in which the projection system is a very important optical system in near-eye display devices, and its function is to project images or videos to the human eye.

[0003] However, the existing projection system has a complex optical design, which makes its system structure complicated and is not conducive to its miniaturization. Therefore, it is difficult to meet the needs of micro-projection equipment (especially the application needs of wearable near-eye display devices).

[0004] Therefore, there is a need for an optimized micro-projection system solution for near-eye display devices. Summary of the invention

[0005] One advantage of the present application is that it provides a method for preparing a projection system, a near-eye display device and an optical component, wherein the projection system assembles a light homogenizing element, a prism carrier and a polarization splitter film together, and omits the existing relay imaging system, so that the projection system is conducive to structural miniaturization.

[0006] Another advantage of the present application is that it provides a method for preparing a projection system, a near-eye display device and an optical component, wherein the light homogenizing element, the prism carrier and the polarization splitter film are assembled together so that the output end face of the light homogenizing element is closer to the display chip, so that the uniform illumination projected from the output end face of the light homogenizing element can still maintain a relatively high uniformity when projected onto the display chip.

[0007] Another advantage of the present application is that it provides a method for preparing a projection system, a near-eye display device and an optical component, wherein the light homogenizing element, the prism carrier and the polarization splitter film are assembled together to form an optical component. This method is conducive to ensuring the relative position relationship between the light homogenizing element, the prism carrier and the polarization splitter film and improving the preparation efficiency.

[0008] Another advantage of the present application is that it provides a method for preparing a projection system, a near-eye display device and an optical component, wherein the consistency of the optical axis of the projection system can be improved by assembling the light homogenizing element, the prism carrier and the polarization splitting film together to have an integrated structure.

[0009] Another advantage of the present application is that it provides a method for preparing a projection system, a near-eye display device and an optical component, wherein the light homogenizing element, the prism carrier and the polarization splitter film are assembled together to form an optical component, so that when assembling the projection system, the optical component can be used as a separate module to cooperate with other components, so as to improve assembly accuracy and assembly efficiency.

[0010] Other advantages and features of the present application will become apparent from the following description, and may be achieved by the means and combinations particularly pointed out in the claims.

[0011] To achieve at least one of the above advantages, the present application provides a projection system, comprising:

[0012] light source;

[0013] An optical component, comprising a light homogenizing element, a prism carrier and a polarization beam splitting film, wherein the light homogenizing element is located on a projection path of the light source and is provided with an optical axis along the projection path, the light homogenizing element has a first end face corresponding to the light source, a second end face opposite to the first end face and an extension extending between the first end face and the second end face; the prism carrier has a light incident surface corresponding to the light homogenizing element, the polarization beam splitting film is fittedly sandwiched between the second end face of the light homogenizing element and the light incident surface of the prism carrier, and the light homogenizing element, the prism carrier and the polarization beam splitting film are assembled together;

[0014] a display chip corresponding to the optical component; and

[0015] A projection lens group is located on the light output path of the optical component.

[0016] In the projection system according to the present application, the second end surface of the light homogenizing element is parallel to the light incident surface of the prism carrier.

[0017] In the projection system according to the present application, a first angle formed between the second end surface of the light homogenizing element and the optical axis is 45°, and a second angle formed between the light incident surface of the prism carrier and the optical axis is 135°.

[0018] In the projection system according to the present application, the polarization splitting film is coated on the light incident surface of the prism carrier and glued to the second end surface of the light homogenizing element by an adhesive. In this way, the polarization splitting film is sandwiched between the second end surface of the light homogenizing element and the light incident surface of the prism carrier.

[0019] In the projection system according to the present application, the polarization splitting film is coated on the second end face of the light homogenizing element and glued to the light incident surface of the prism carrier by an adhesive. In this way, the polarization splitting film is sandwiched between the second end face of the light homogenizing element and the light incident surface of the prism carrier.

[0020] In the projection system according to the present application, the refractive index of the light homogenizing element is consistent with the refractive index of the prism carrier.

[0021] In the projection system according to the present application, the second end surface of the light homogenizing element and the light incident surface of the prism carrier have consistent size and shape.

[0022] In the projection system according to the present application, the display chip is disposed on the bottom side of the light homogenizing element and parallel to the optical axis, and the projection lens group is disposed on the top side of the light homogenizing element opposite to the bottom side.

[0023] In the projection system according to the present application, the display chip is disposed on a first side of the prism carrier and perpendicular to the optical axis, and the projection lens group is disposed on a second side of the prism carrier adjacent to the first side.

[0024] In the projection system according to the present application, the optical component further includes a first anti-reflection film disposed on the surface of the first side.

[0025] In the projection system according to the present application, the optical component further includes a second anti-reflection film disposed on the surface of the second side.

[0026] In the projection system according to the present application, the optical component further includes a first anti-reflection film disposed on the surface of the bottom side of the light homogenizing element.

[0027] In the projection system according to the present application, the optical component further includes a second anti-reflection film disposed on a surface of the prism carrier facing the projection lens group.

[0028] In the projection system according to the present application, the distance between the display chip and the light homogenizing element is less than or equal to 0.5 mm.

[0029] In the projection system according to the present application, the distance between the display chip and the prism carrier is less than or equal to 0.5 mm.

[0030] In the projection system according to the present application, the display chip is an LCOS display chip.

[0031] In the projection system according to the present application, the light source is superimposed on the first end surface of the light homogenizing element.

[0032] In the projection system according to the present application, the projection system further includes a focusing element disposed between the light source and the light homogenizing element.

[0033] In the projection system according to the present application, the focusing element is integrated with the light source.

[0034] In the projection system according to the present application, the width dimension of the light homogenizing element is consistent along its set length direction.

[0035] In the projection system according to the present application, the extension portion includes a head portion that gradually expands from the first end surface along a set length direction thereof, and a main body portion that extends from the head portion to the second end surface.

[0036] In the projection system according to the present application, the angle formed by the side surface of the head and the optical axis has a preset angle such that the divergence angle of the light emitted from the second end surface of the light homogenizing element is less than or equal to 40°.

[0037] In the projection system according to the present application, the preset angle ranges from 7 to 15 degrees, and the length of the head ranges from 10 mm to 15 mm.

[0038] In the projection system according to the present application, the height dimension of the prism carrier is consistent with the width dimension of the light homogenizing element.

[0039] In the projection system according to the present application, the height dimension of the prism carrier is consistent with the width dimension of the main body.

[0040] According to another aspect of the present application, a near-eye display device is also provided, which includes the projection system as described above.

[0041] According to another aspect of the present application, a method for preparing an optical component is also provided, comprising:

[0042] Providing a light homogenizing element and a prism carrier;

[0043] Forming a polarization beam splitting film on the light incident surface of the prism carrier by a coating process; and

[0044] The polarization beam splitting film is glued to the second end surface of the light homogenizing element by an adhesive, so that the light homogenizing element, the polarization beam splitting film and the prism carrier are assembled together.

[0045] According to another aspect of the present application, a method for preparing an optical component is also provided, comprising:

[0046] Providing a light homogenizing element and a prism carrier;

[0047] Forming a polarization splitting film on the second end surface of the light homogenizing element by a coating process; and

[0048] The polarization beam splitting film is glued to the light incident surface of the prism carrier by the adhesive, so that the light homogenizing element, the polarization beam splitting film and the prism carrier are assembled together.

[0049] Further objectives and advantages of the present application will be fully reflected through understanding of the following description and drawings.

[0050] These and other objects, features and advantages of the present application are fully reflected in the following detailed description, drawings and claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] By describing the embodiments of the present application in more detail in conjunction with the accompanying drawings, the above and other purposes, features and advantages of the present application will become more apparent. The accompanying drawings are used to provide a further understanding of the embodiments of the present application and constitute a part of the specification. Together with the embodiments of the present application, they are used to explain the present application and do not constitute a limitation of the present application. In the accompanying drawings, the same reference numerals generally represent the same components or steps.

[0052] Figure 1 The figure shows a schematic structural diagram of an existing projection system for a near-eye display device.

[0053] Figure 2 The figure shows a schematic diagram of the projection effect of the existing projection system.

[0054] Figure 3 The figure shows a schematic diagram of the structure of a display chip in an existing projection system.

[0055] Figure 4A The figure shows a schematic structural diagram of a polarization beam splitter prism in an existing projection system.

[0056] Figure 4B The figure shows one of the working schematic diagrams of the polarization beam splitter prism in the existing projection system.

[0057] Figure 4C The figure shows the second working schematic diagram of the polarization beam splitting prism in the existing projection system.

[0058] Figure 5 A schematic diagram of a projection system for a near-eye display device according to an embodiment of the present application is illustrated.

[0059] Figure 6 FIG. 1 is a schematic diagram of a modified implementation of the projection system according to an embodiment of the present application.

[0060] Figure 7FIG. 1 is a schematic diagram showing another variant implementation of the projection system according to an embodiment of the present application.

[0061] Figure 8 FIG. 1 is a schematic diagram showing another variant implementation of the projection system according to the embodiment of the present application.

[0062] Fig.9A and Fig. 9B The figure shows a schematic diagram comparing the illumination test result of the projection system according to the embodiment of the present application with the existing illumination test result.

[0063] Fig. 10A and Fig. 10B The figure shows a schematic diagram comparing the illumination distribution effect of the projection system according to the embodiment of the present application with the illumination distribution result of the existing projection system.

[0064] Fig.11 A schematic diagram of a near-eye display device according to an embodiment of the present application is shown. DETAILED DESCRIPTION

[0065] Below, the exemplary embodiments according to the present application will be described in detail with reference to the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application, and it should be understood that the present application is not limited to the exemplary embodiments described here.

[0066] Application Overview

[0067] As mentioned above, the projection system is a very important optical system in near-eye display devices, and its function is to project images or videos to the human eye. However, the existing projection system has a complex optical design, which makes its system structure complicated and is not conducive to its miniaturization. Therefore, it is difficult to meet the application requirements of near-eye display devices.

[0068] More specifically, Chinese patent CN101614946A discloses a projection system for a near-eye display device. Figure 1 The figure shows a schematic diagram of the structure of an existing projection system for near-eye display devices. Figure 1 As shown, the existing projection system for near-eye display devices includes: a light source 1P, a homogenizing rod 2P, a relay imaging system 3P, a display chip 4P, a PBS prism 5P (Polarization beam splitter) and a projection lens 6P. Its working process is: the light emitted by the light source 1P is uniformed by the homogenizing rod 2P, amplified by the relay imaging system 3P, and then incident on the display chip 4P after being acted upon by the PBS prism 5P, and then modulated into an image by the display chip 4P, and then the image is projected through the PBS prism 5P through the projection lens 6P.

[0069] In the existing projection system, the display chip 4P is a reflective display chip 4P (LCOS display chip 4P), and the PBS prism 5P is compatible with the LCOS display chip 4P. Figure 3 The figure shows a schematic diagram of the structure of a display chip 4P in an existing projection system. Figure 3 As shown, the reflective display chip 4P includes a glass bottom layer 41P, a liquid crystal layer 42P, an aluminum reflector electrode 43P and a CMOS active drive circuit 44P. Figure 4A The figure shows a schematic diagram of the structure of a polarization beam splitter prism in an existing projection system. Figure 4A As shown, the PBS prism 5P is formed by gluing two prisms (an upper prism 51P and a lower prism 52P) together and a PBS film 53P is coated on one surface of the prism, wherein when natural light is incident on the PBS film 53P, P polarized light is transmitted and S polarized light is reflected. Figure 4B and Figure 4C The figure shows the working schematic diagram of the polarization beam splitter prism in the existing projection system. Figure 4B and Figure 4C As shown, the incident S polarized light is reflected by the PBS film 53P and then irradiates the display chip 4P, wherein, when the applied voltage of the corresponding pixel in the liquid crystal layer 42P is 0, the polarization direction of the input S polarized light does not deflect when passing through the corresponding pixel, and it is reflected back after reaching the bottom and outputs S polarized light, and passes through the PBS prism 5P. The reflected S polarized light cannot enter the projection light path, and the light output is zero, and the pixel is in a "dark state". On the contrary, when the corresponding pixel is externally applied with a voltage, the polarization direction of the input S polarized light deflects when passing through the liquid crystal layer 42P, reaches the bottom and reflects back to output P polarized light, directly passes through the PBS prism 5P, and enters the projection light path, and the corresponding pixel is in a "bright state".

[0070] In the existing imaging system, the light projected by the light source 1P is required to be uniformly projected to the display chip 4P. This technical requirement is achieved by the light homogenizing rod 2P and the relay imaging system 3P disposed between the light source 1P and the display chip 4P. The light homogenizing rod 2P is used to homogenize the illumination projected by the light source 1P to form uniform illumination. Figure 2 shown. Figure 2 FIG. 4 is a schematic diagram showing the projection effect of an existing projection system. Figure 2 As shown, the light emitted by the light source 1P is reflected multiple times in the light homogenizing rod 2P, and each reflection forms a virtual light source 1P image. The two-dimensional virtual light source 1P matrix formed by multiple reflections makes the light uniform. Figure 2As shown, this is limited to uniform illumination near the exit end face of the homogenizing rod 2P. Once the light is away from the exit end face of the homogenizing rod 2P, it will become uneven again. More specifically, generally speaking, the light will become obviously uneven 0.5mm away from the exit end face of the homogenizing rod 2P. The use of a reflective display chip 4P requires a PBS prism 5P to be set at the front end of the display chip 4P, which causes the distance from the exit end face of the homogenizing rod 2P to the display chip 4P to be far more than 0.5mm. Therefore, in the existing imaging system, a relay imaging system 3P is introduced to relay the uniform illumination of the exit end face of the homogenizing rod 2P to the display chip 4P.

[0071] However, due to the existence of the relay imaging system 3P, the structure of the existing projection system becomes complicated, which is not conducive to its miniaturization, especially for wearable near-eye display devices, the size seriously affects the experience of the wearable device. In other words, the existence of the relay imaging system 3P is a contradictory component for the existing projection system. Its existence is inevitable, because without it, the existing projection system cannot project uniform illumination to the display chip 4P, but it is precisely because of its existence that the optical design and structural design of the existing projection system become complicated, which does not meet the development needs of miniaturization of near-eye display devices.

[0072] Based on this, the basic idea of ​​the inventor of the present application is to conceive an optical design solution that can achieve the goal of projecting uniform illumination onto the display chip 4P without the need for a relay imaging system 3P.

[0073] After research, the inventor of the present application found that the projection light projected by the light source 1P is uniform at its exit end face due to the action of the light homogenizing rod 2P, and the light becomes obviously non-uniform when the distance from the exit end face of the light homogenizing rod 2P exceeds 0.5 mm. That is, if the exit end face of the light homogenizing rod 2P can be arranged as close to the display chip 4P as possible, it can be satisfied that the uniform illumination projected from the exit end face of the light homogenizing rod 2P can be uniformly projected onto the display chip 4P without the need for a relay imaging system 3P.

[0074] Furthermore, in the existing imaging system, the key factor affecting the layout distance between the output end face of the light homogenizing rod 2P and the display chip 4P lies in the structural design of the existing PBS prism 5P (including an upper prism 51P, a lower prism 52P and a PBS film 53P arranged between the upper prism 51P and the lower prism 52P). More specifically, due to the existence of the lower prism 52P, it is difficult to reduce the layout distance between the output end face of the light homogenizing rod 2P and the display chip 4P.

[0075] Based on this, the inventor of the present application conceived: whether it is possible to replace the function of the lower prism 52P by a part of the homogenizing rod 2P, so as to reduce the layout distance between the output end face of the homogenizing rod 2P and the display chip 4P, so as to meet the technical requirement that the uniform illumination projected from the output end face of the homogenizing rod 2P can be uniformly projected onto the display chip 4P without the need for a relay imaging system 3P.

[0076] Therefore, the present application realizes that the key to the lower prism 52P being able to play its role is that: first, it has a refractive index consistent with that of the upper prism 51P; second, it cooperates with the upper prism 51P to add a PBS film 53P between the two. That is, if the light homogenizing rod 2P can have a refractive index consistent with that of the upper prism 51P, and it provides a surface for cooperating with the surface of the upper prism 51P to sandwich the PBS, then a part of the light homogenizing rod 2P can replace the role of the lower prism 52P, thereby reducing the layout distance between the exit end face of the light homogenizing rod 2P and the display chip 4P, so as to meet the technical requirement that the uniform illumination projected from the exit end face of the light homogenizing rod 2P can be uniformly projected onto the display chip 4P without the need for a relay imaging system 3P.

[0077] Based on this, the present application provides a projection system, which includes: a light source; an optical component, including a light homogenizing element, a prism carrier and a polarization splitting film, wherein the light homogenizing element is located on the projection path of the light source and is provided with an optical axis along the projection path, the light homogenizing element has a first end face corresponding to the light source, a second end face opposite to the first end face and an extension portion extending between the first end face and the second end face; the prism carrier has a light incident surface corresponding to the light homogenizing element, and the polarization splitting film is fitly sandwiched between the second end face of the light homogenizing element and the light incident surface of the prism carrier, so that the light homogenizing element, the prism carrier and the polarization splitting film have an integrated structure; a display chip corresponding to the polarization splitting component; and a projection lens group located on the light output path of the polarization splitting component.

[0078] After introducing the basic principles of the present application, various non-limiting embodiments of the present application will be described in detail with reference to the accompanying drawings.

[0079] Exemplary Projection Systems

[0080] Figure 5 FIG. 1 is a schematic diagram of a projection system for a near-eye display device according to an embodiment of the present application. Figure 5As shown, the projection system 100 according to an embodiment of the present application includes: a light source 10, an optical component 20 corresponding to the light source 10 and located on the projection path of the light source 10, a display chip 30 corresponding to the optical component 20, and a projection lens group 40 located on the light output path of the optical component 20, wherein the optical component 20 includes a light homogenizing element 21, a prism carrier 22 and a polarization splitter film 23.

[0081] like Figure 5 As shown, in the embodiment of the present application, the light homogenizing element 21 is located on the projection path of the light source 10 and is provided with an optical axis X along the projection path, and the light homogenizing element 21 has a first end face 211 corresponding to the light source 10, a second end face 212 opposite to the first end face 211, and an extension portion 213 extending between the first end face 211 and the second end face 212. The prism carrier 22 has a light incident surface 221 corresponding to the light homogenizing element 21, and the polarization splitting film 23 is sandwiched between the second end face 212 of the light homogenizing element 21 and the light incident surface 221 of the prism carrier 22. In this way, the light homogenizing element 21, the prism carrier 22 and the polarization splitting film 23 are assembled together to have an integrated structure.

[0082] More specifically, if Figure 5 As shown, in the embodiment of the present application, the light source 10 is superimposed on the first end surface 211 of the light homogenizing element 21, so that the light projected by the light source 10 can be incident into the light homogenizing element 21 through the first end surface 211. During operation, the light source 10 projects light to the light homogenizing element 21, and the light homogenizing element 21 homogenizes the projected light to form uniform illumination on its exit end surface (i.e., on the second end surface 212); further, under the action of the polarization splitting film 23 and the prism carrier 22, the uniform illumination can be relatively uniformly projected to the display chip 30, so as to be modulated by the display chip 30 into an image with a specific pattern and projected to the outside through the projection lens group 40.

[0083] It should be noted that in the embodiment of the present application, the second end face 212 of the light homogenizing element 21 is an inclined surface relative to the optical axis X set thereto, that is, the exit end face of the light homogenizing element 21 is a beveled surface. More specifically, in the embodiment of the present application, the first angle formed by the second end face 212 of the light homogenizing element 21 and the optical axis X is complementary to the second angle formed by the light incident surface 221 of the prism carrier 22 and the optical axis X, and the refractive index of the light homogenizing element 21 is consistent with the refractive index of the prism carrier 22, so that the end of the light homogenizing element 21 close to the second end face 212 can replace the role of the existing lower prism, so as to achieve the technical purpose of reducing the layout distance between the exit end face of the light homogenizing element 21 and the display chip 30, thereby meeting the technical requirement that the uniform illumination projected from the exit end face of the light homogenizing element 21 can be uniformly projected onto the display chip 30 without the need for a relay imaging system. That is, in the embodiment of the present application, the second end surface 212 of the light homogenizing element 21 is parallel to the light incident surface 221 of the prism carrier.

[0084] Preferably, in the embodiment of the present application, the first angle is 45 degrees, and the second angle is 135 degrees, so that the optical system design of the projection system 100 is relatively simple. Of course, in other examples of the present application, the first angle and the second angle can also be set to other values, which is not limited by the present application.

[0085] In order to ensure that the uniform illumination projected from the exit end face of the light homogenizing element 21 can be uniformly projected onto the display chip 30, in the embodiment of the present application, preferably, the distance between the display chip 30 and the optical component 20 is less than or equal to 0.5 mm. More specifically, Figure 5 As shown, in the embodiment of the present application, the display chip 30 is disposed on the bottom side of the light homogenizing element 21 (particularly, as shown in FIG. Figure 5 In the illustrated example, the side where the longer side of the light homogenizing element 21 is located forms the bottom side of the light homogenizing element 21 and is parallel to the optical axis X, and the projection lens group 40 is arranged on the top side of the light homogenizing element 21 opposite to the bottom side, that is, the display chip 30 and the projection lens group 40 are respectively located on the upper and lower sides of the light homogenizing element 21, and the upper and lower sides of the display chip 30 and the projection lens group 30 relative to the light homogenizing element 21 are not adjustable, wherein the upper surface of the prism carrier 22 forms the light exit surface 222 of the prism carrier 22. That is, preferably, in the embodiment of the present application, the distance between the display chip 30 and the light homogenizing element 21 is less than or equal to 0.5 mm, so that the uniform illumination from the exit end of the light homogenizing element 21 can still maintain a relatively high uniformity when projected onto the display chip 30.

[0086] Furthermore, in the embodiment of the present application, the display chip 30 is also a reflective display chip, for example, an LCOS display chip. It should be known to those skilled in the art that the LCOS display chip 30 is a dedicated chip made by integrating a display matrix and related drive circuits on a silicon chip using a design and manufacturing method compatible with large-scale integrated circuits. The LCOS display chip is a new flat panel display technology with development prospects. Compared with other display technologies, it has a series of advantages such as waferless mode, wide product sources, open architecture, and low-cost potential, making it one of the mainstream technologies in the field of high-end information displays in the future.

[0087] In the embodiment of the present application, the allowable incident angle of the display chip 30 is within 30°, that is, the maximum deviation angle of the projection light that the display chip 30 can receive is not greater than 30° (wherein the incident angle is the angle between the projection light and the optical axis of the display chip 30).

[0088] It should be noted that in the embodiment of the present application, the polarization beam splitter film 23 is sandwiched between the second end face 212 of the light homogenizing element 21 and the light incident surface 221 of the prism carrier 22, and the light homogenizing element 21, the prism carrier 22 and the polarization beam splitter film 23 are assembled together to have an integrated structure. That is, in the embodiment of the present application, not only does the light homogenizing element 21 replace the existing lower prism, but also, in terms of structural design, the light homogenizing element 21, the polarization beam splitter film 23 and the prism carrier 22 can also be configured as an integrated structure, that is, the light homogenizing element 21, the polarization beam splitter film 23 and the prism carrier 22 can be used as a separate module to participate in the optical design of the projection system 100, so that not only the assembly efficiency and matching accuracy of the projection system 100 can be improved, but also the consistency of the optical axis X of the projection system 100 can be improved.

[0089] In a specific example of the present application, the polarization splitting film 23 is coated on the light incident surface 221 of the prism carrier 22 and glued to the second end surface 212 of the light homogenizing element 21 by an adhesive, so that the polarization splitting film 23 is sandwiched between the second end surface 212 of the light homogenizing element 21 and the light incident surface 221 of the prism carrier 22. That is, in this example, the polarization splitting film 23 is first formed on the light incident surface 221 of the prism carrier 22 by a coating process, and further, is bonded to the second end surface 212 of the light homogenizing element 21 by an adhesive.

[0090] It is worth mentioning that in the preparation process corresponding to this example, the polarization splitter film 23 and the prism carrier 22 can be used as independent components to participate in the assembly of the projection system 100 .

[0091] In another specific example of the present application, the polarization splitting film 23 is coated on the second end face 212 of the light homogenizing element 21 and glued to the light incident surface 221 of the prism carrier 22 by an adhesive, so that the polarization splitting film 23 is sandwiched between the second end face 212 of the light homogenizing element 21 and the light incident surface 221 of the prism carrier 22. That is, in this example, the polarization splitting film 23 is first formed on the second end face 212 of the light homogenizing element 21 by a coating process, and further, is bonded to the light incident surface 221 of the prism carrier 22 by an adhesive.

[0092] It is worth mentioning that in the preparation process corresponding to this example, the polarization beam splitting film 23 and the light homogenizing element 21 can be used as independent components to participate in the assembly of the projection system 100 .

[0093] Furthermore, if Figure 5 As shown, in the embodiment of the present application, the light homogenizing element 21 has an elongated structure, and its width dimension is consistent along its set length direction and the width dimension of the light homogenizing element 21 is consistent with the height dimension of the prism carrier 22. And, preferably, in the implementation of the present application, the second end face 212 of the light homogenizing element 21 has a consistent size and shape with the light incident surface 221 of the prism carrier 22. With such a size configuration, during the process of assembling the optical component 20, the second end face 212 of the light homogenizing element 21 can be perfectly aligned with the light incident surface 221 of the prism carrier 22 and the polarization splitting film 23 can be sandwiched therebetween. In particular, as Figure 5 As shown, in the embodiment of the present application, the optical component 20 formed by the light homogenizing element 21, the polarization beam splitting film 23 and the prism carrier 22 has a compact and small structural design.

[0094] In order to improve the transmittance of the projection light on the surface, in the embodiment of the present application, an anti-reflection film (not shown in the figure) may be provided on the surface of the light homogenizing element 21 facing the display chip 30 and / or the surface of the prism carrier 22 facing the projection lens group 40 (i.e., the light exiting surface 222). That is, in the embodiment of the present application, the optical component 20 further includes a first anti-reflection film (not shown in the figure) provided on the surface of the bottom side of the light homogenizing element 21 and / or a second anti-reflection film (not shown in the figure) provided on the surface of the prism carrier 22 facing the projection lens group 40.

[0095] Figure 6 FIG. 1 is a schematic diagram of a modified implementation of the projection system 100 according to an embodiment of the present application. Figure 5 In the illustrated projection system 100, in this variant embodiment, the setting position of the display chip 30 is adjusted. Specifically, in this variant embodiment, the display chip 30 is set on the first side of the prism carrier 22 and perpendicular to the optical axis X, and the projection lens group 40 is set on the second side of the prism carrier 22 adjacent to the first side. In this way, the light received by the display chip 30 is P-polarized light transmitted through the polarization splitter film 23.

[0096] In particular, in Figure 5 In the projection system 100 shown in the figure, if the angle of the light is too large, part of the light will directly enter the display chip 30 without passing through the polarization beam splitter film 23, resulting in both P-polarized light and S-polarized light in the light received by the display chip 30, which will weaken the image modulation capability of the display chip 30, that is, the quality of the projected image will deteriorate. Figure 5 In the illustrated projection system 100, the light angle requirement is relatively high. In this variant embodiment, the display chip 30 is arranged at one side of the prism carrier 22, so that all the light entering the display chip 30 is P-polarized light filtered by the polarization beam splitting film 23, thereby ensuring that the image modulation capability of the display chip 30 is not affected.

[0097] In addition, since there is no need to consider the situation where the light enters the display chip 30 without passing through the polarization splitting film 23 , in this modified embodiment, the maximum allowable incident angle of the display chip 30 can be appropriately increased.

[0098] Furthermore, in order to ensure that the uniform illumination at the output end of the light homogenizing element 21 can still maintain a relatively high uniformity when projected onto the display chip 30 , preferably, in this variant embodiment, the distance between the display chip 30 and the prism carrier 22 is less than or equal to 0.5 mm.

[0099] Figure 7 FIG. 2 is a schematic diagram showing another variant implementation of the projection system 100 according to an embodiment of the present application. Figure 7 As shown, in this variant implementation, the projection system 100 further includes a focusing element 50 (e.g., a condenser) disposed between the light source 10 and the light homogenizing element 21, and the focusing unit is used to gather the light projected by the light source 10. That is, before the light homogenizing element 21, the projection system 100 is further provided with a focusing unit for reducing the divergence angle of the light, so as to prevent the light from having an excessively large divergence angle when entering the light homogenizing element 21.

[0100] In a specific example of this variant implementation, the light focusing element 50 can be independently provided with the light source 10, that is, the light focusing element 50 and the light source 10 are two independent components. Of course, in other specific examples of this variant implementation, the light focusing element 50 can be integrated with the light source 10, that is, the light source 10 and the light focusing element 50 have an integrated structure.

[0101] Figure 8 FIG. 2 is a schematic diagram showing another variant implementation of the projection system 100 according to an embodiment of the present application. Figure 8 As shown, in this variant embodiment, the extension portion 213 includes a head portion 214 gradually expanding from the first end surface 211 along the set length direction thereof, and a main body portion 215 extending from the head portion 214 to the second end surface 212. That is, in this variant embodiment, the light homogenizing element 21 is provided with a cone angle at its incident end portion, so as to achieve the purpose of gathering light through the cone angle.

[0102] In particular, in this variant embodiment, the angle formed by the side surface of the head 214 and the optical axis X has a preset angle such that the divergence angle of the light emitted from the second end surface 212 of the light homogenizing element 21 is less than or equal to 40°. More specifically, in this variant embodiment, the length of the head 214 ranges from 10 mm to 15 mm, and the preset angle ranges from 7 to 15 degrees. For example, in a specific example of this variant embodiment, the length of the head 214 is 13.36 mm, the refractive index of the light homogenizing element 21 is 1.75, and the preset angle is 9.19°.

[0103] It is worth mentioning that, preferably, in a modified embodiment, the height dimension of the prism carrier 22 is consistent with the width dimension of the main body 215 .

[0104] In summary, the projection system 100 based on the embodiment of the present application is explained, wherein the projection system 100 can meet the technical requirement that the uniform illumination projected from the output end face of the light homogenizing element 21 can be uniformly projected onto the display chip 30 without the need for a relay imaging system. In addition, in the projection system 100, the light homogenizing element 21, the prism carrier 22 and the polarization beam splitting film 23 are integrated to facilitate the miniaturization of the projection system 100.

[0105] Fig.9A and Fig. 9B FIG. 1 is a schematic diagram showing a comparison between the illumination test result of the projection system 100 according to an embodiment of the present application and the existing illumination test result, wherein: Fig.9Arepresents the illumination test result of the projection system 100 according to the embodiment of the present application, Fig. 9B A comparative schematic diagram showing the illumination test results of the existing projection system 100 is shown in FIG. Fig.9A and Fig. 9B In the left figure, different grayscale blocks indicate different illumination levels. In the right figure, the ordinate indicates the illumination level, and the abscissa indicates the proportion of each grayscale block to the total. Fig.9A and Fig. 9B It can be seen that Fig.9A Medium illumination is more concentrated. Fig. 10A and Fig. 10B FIG. 1 is a schematic diagram showing a comparison between the illumination distribution effect of the projection system 100 according to an embodiment of the present application and the illumination distribution result of the existing projection system 100 , wherein: Fig. 10A The figure shows the illumination distribution effect of the projection system 100 according to the embodiment of the present application. Fig. 10B The figure shows the illumination distribution effect of the conventional projection system 100 .

[0106] like Fig.9A and Fig. 9B ,as well as, Fig. 10A and Fig. 10B As shown, the projection system 100 provided according to the embodiment of the present application and its variant implementation has a better light uniformity effect than the existing projection system 100, and its combined light chromaticity coordinates are more concentrated than the existing solution, and the display effect is better.

[0107] Schematic near-eye display device

[0108] According to another aspect of the present application, a near-eye display device 200 is also provided, which includes the projection system 100 as described above.

[0109] Fig.11 FIG. 2 is a schematic diagram of a near-eye display device 200 according to an embodiment of the present application. Fig.11 In the illustrated example, the near-eye display device 200 is implemented as a wearable near-eye display device 200. It should be understood that the projection system 100 according to the embodiment of the present application has a relatively smaller, compact and small optical design and structural design, and therefore, the projection system 100 matches the development trend of miniaturization of the near-eye display device 200.

[0110] Exemplary Methods of Making Optical Assemblies

[0111] According to another aspect of the present application, a method for preparing an optical component 20 is also provided.

[0112] Accordingly, according to the preparation method of the optical component 20 of the embodiment of the present application, the method includes: first, providing a light homogenizing element 21 and a prism carrier 22; then, forming a polarization splitting film 23 on the light incident surface 221 of the prism carrier 22 through a coating process; then, gluing the polarization splitting film 23 to the second end surface 212 of the light homogenizing element 21 through an adhesive, so that the light homogenizing element 21, the polarization splitting film 23 and the prism carrier 22 are assembled together to have an integrated structure.

[0113] Alternatively, according to the preparation method of the optical component 20 of the embodiment of the present application, the method includes: first, providing a light homogenizing element 21 and a prism carrier 22; remember, forming a polarization splitting film 23 on the second end face 212 of the light homogenizing element 21 through a coating process; then, gluing the polarization splitting film 23 to the light incident surface 221 of the prism carrier 22 through the adhesive, so that the light homogenizing element 21, the polarization splitting film 23 and the prism carrier 22 are assembled together to have an integrated structure.

[0114] Preferably, a solution of coating the prism carrier 22 is adopted, because in this way, the existing coating process and equipment of PBS prism can be used, which is more convenient and saves cost.

[0115] It should be understood that the light homogenizing element 21, the prism carrier 22 and the polarization splitter film 23 are assembled together to form an optical component 20, so that when assembling the projection system 100, the optical component 20 can be used as a separate module to cooperate with other components to improve assembly accuracy and assembly efficiency.

[0116] It should be understood by those skilled in the art that the embodiments of the present invention described above and shown in the accompanying drawings are only examples and do not limit the present invention. The purpose of the present invention has been fully and effectively achieved. The functional and structural principles of the present invention have been demonstrated and explained in the embodiments, and the embodiments of the present invention may be deformed or modified in any way without departing from the principles.

Claims

1. A projection system, characterized in that: include: light source; An optical component, comprising a light homogenizing element, a prism carrier and a polarization beam splitting film, wherein the light homogenizing element is located on a projection path of the light source and is provided with an optical axis along the projection path, the light homogenizing element has a first end face corresponding to the light source, a second end face opposite to the first end face and an extension extending between the first end face and the second end face; the prism carrier has a light incident surface corresponding to the light homogenizing element, the polarization beam splitting film is fittedly sandwiched between the second end face of the light homogenizing element and the light incident surface of the prism carrier, and the light homogenizing element, the prism carrier and the polarization beam splitting film are assembled together; a display chip corresponding to the optical component; and A projection lens group located on the light output path of the optical component; The second end face of the light homogenizing element forms an exit end face of the light homogenizing element, and the second end face is a beveled face, and a first angle formed between the second end face and the optical axis is 45°; a second angle formed between the light incident surface of the prism carrier and the optical axis is 135°; The display chip is arranged on the bottom side of the side where the second end face of the light homogenizing element is located and is parallel to the optical axis, the projection lens group is arranged on the top side of the light homogenizing element opposite to the bottom side, and the light source is superimposed on the first end face of the light homogenizing element, so that after the light source projects light to the light homogenizing element during operation, the light homogenizing element homogenizes the light projected by the light source to form uniform illumination on its exit end face, and under the action of the polarization beam splitting film and the prism carrier, the uniform illumination can be relatively uniformly projected to the display chip, so as to be modulated by the display chip into an image with a specific pattern and projected to the outside through the projection lens group; The refractive index of the light homogenizing element is consistent with the refractive index of the prism carrier; the optical component further includes a first anti-reflection film arranged on the surface of the bottom side of the light homogenizing element and a second anti-reflection film arranged on the surface of the prism carrier facing the projection lens group.

2. The projection system according to claim 1, wherein: The polarization splitting film is coated on the light incident surface of the prism carrier and glued to the second end surface of the light homogenizing element by an adhesive, so that the polarization splitting film is sandwiched between the second end surface of the light homogenizing element and the light incident surface of the prism carrier.

3. The projection system according to claim 1, wherein: The polarization splitting film is coated on the second end surface of the light homogenizing element and glued to the light incident surface of the prism carrier by an adhesive, so that the polarization splitting film is sandwiched between the second end surface of the light homogenizing element and the light incident surface of the prism carrier.

4. The projection system according to claim 2, wherein: The second end surface of the light homogenizing element has consistent size and shape with the light incident surface of the prism carrier.

5. The projection system according to claim 1, wherein: The distance between the display chip and the light homogenizing element is less than or equal to 0.5 mm.

6. The projection system according to claim 1, wherein: The display chip is an LCOS display chip. 7 . The projection system according to claim 1 , further comprising a focusing element disposed between the light source and the light homogenizing element.

8. The projection system according to claim 7, wherein: The light focusing element is integrated with the light source.

9. The projection system according to claim 1, wherein: The extension portion includes a head portion gradually expanding from the first end surface along a set length direction thereof, and a main body portion extending from the head portion to the second end surface.

10. The projection system according to claim 9, wherein: The angle formed by the side surface of the head and the optical axis is a preset angle such that the divergence angle of the light emitted from the second end surface of the light homogenizing element is less than or equal to 40°.

11. The projection system according to claim 10, wherein: The preset angle ranges from 7 to 15 degrees, and the length of the head ranges from 10 mm to 15 mm.

12. The projection system according to claim 9, wherein: The height dimension of the prism carrier is consistent with the width dimension of the light homogenizing element.

13. The projection system according to claim 12, wherein: The height dimension of the prism carrier is consistent with the width dimension of the main body.

14. A near-eye display device, characterized in that: Comprising a projection system as claimed in any one of claims 1 to 13.

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