CN116107142A - Projection module and illumination system thereof - Google Patents

Abstract

The invention provides a projection module and an illumination system thereof, wherein the illumination system comprises a light source, a condensing lens group and a light homogenizing rod, wherein light rays emitted by the light source are converged by the condensing lens group to form a condensing light path, the light rays enter the light homogenizing rod along the condensing light path and are reflected by the light homogenizing rod to form at least one reflecting light path, the condensing lens group comprises a first lens and a second lens, the first lens is positioned at the front end of the second lens in the light incident direction, and the second lens is a cylindrical mirror with focal power along the V direction, so that the light rays are larger than the light ray divergence angle along the V direction along the H direction, and the reflection times of the light rays along the H direction are improved.

Description

Projection module and illumination system thereof

Technical Field

The present invention relates to the field of optical imaging technologies, and in particular, to a projection module and an illumination system thereof.

Background

The projection display technology based on the micro display chip enables projection equipment to develop towards miniaturization and high resolution, and the projection module is a way for realizing large-size high-resolution display with high cost performance by combining optics and mature semiconductor technology.

Fig. 1 and 2 disclose a prior art projection module, wherein the projection module comprises a light source, a light homogenizing rod, a relay lens, a PBS prism, an LCOS chip, and a projection lens. The light source generally comprises a condensing lens, the angle of the light is controlled, the light is homogenized by a light homogenizing rod to form uniform illumination at the emergent end of the light homogenizing rod, the uniform illumination is imaged to an LCOS chip by a relay lens, and the uniform illumination is modulated into an image by LCOS and then projected by a projection lens.

The light source emits light rays which are reflected for multiple times in the light homogenizing rod, a virtual light source image can be formed by each reflection, and a two-dimensional virtual light source matrix is formed by multiple reflections, so that the light is more uniform. However, this is limited to having uniform illumination near the exit end of the light rod, which is again non-uniform once it is far from the exit end of the light rod, and generally the light becomes significantly non-uniform at 0.5mm distance from the exit end of the light rod, whereas the use of reflective display chips such as LCOS requires the PBS prism to be disposed in front of the display chip, which results in a significant increase in the distance from the exit end of the light rod to the display chip, so that a relay lens is generally disposed in the prior art to image the uniform illumination of the exit end of the light rod onto the LCOS chip. The addition of the relay lens not only increases the complexity and volume of the system, but also makes the projection system with more parts difficult to assemble, the probability of assembly errors is higher, and the importance of the consistency of the optical axes of the parts to the performance of the projection system is self-evident.

Fig. 3 is a chinese patent application publication No. CN101614946a, which discloses a projection system, including a light source (1), a light homogenizing rod (2), a relay imaging system (3), a display chip (5), a PBS prism (4), and a projection lens (6). The light emitted by the light source is homogenized by the light homogenizing rod, shaped by the relay imaging system, then enters the display chip, is modulated into an image by the display chip, and then is projected by the projection lens. In the illustration, a reflective display chip LCOS is shown, so a PBS prism is required. In the scheme, the magnification of the relay imaging system is 3-10 times, and the relay imaging system has beam shaping capability.

In the technical scheme of the application, the light beam emitted by the light source is shaped by an optical device to obtain parallel or approximately parallel light, and the light is homogenized by a homogenizing rod. The light beam with a large angle emitted by the light source directly enters the light rod, and the light beam can be reflected for multiple times in the shorter light rod due to the large angle of the incident light beam, and illumination with uniform distribution is formed on the emergent end face of the light rod; because the magnification of the relay imaging system is 3-10, the step of optical shaping is completed in the relay imaging system, and uniform illumination of the emergent end face of the optical rod is amplified and imaged on the micro-display chip through the relay imaging system, and meanwhile, the requirement of the incident angle of light on the micro-display chip can be met.

Even if the light source is directly attached to the incident end face of the light homogenizing rod, the incident light with a larger angle is reflected in the light homogenizing rod for multiple times, so that the structural size of the light homogenizing rod is shortened, the existence of the relay imaging system is required to image uniform illumination of the emergent end face of the light homogenizing rod to the display chip, and the existence of the relay imaging system complicates the structure of the projection system, so that the miniaturization of the projection system is not facilitated, and particularly in a miniature projection system used in wearable equipment, the size seriously influences the experience of the wearable equipment.

And because the relay imaging system needs to amplify the uniform illumination of the exit end face of the light homogenizing rod enough to cover the display chip, the relay imaging system has 3-10 times of amplifying capability as in the patent, and a lens with a certain amplifying capability needs to have a shorter focal length, generally has a shorter focal length as the curvature of the lens surface is larger, generally has a larger thickness, or is realized by using a plurality of lenses as in the patent, which all results in larger volume of the relay imaging system and is unfavorable for the application of the illumination system in a micro projector.

In addition, another light homogenizing device, an optical integrator, is disclosed in chinese patent publication No. CN101943845a, which generally includes a front collimator, two microlens arrays, and a rear collimator. The optical integrator is also an optical device for homogenizing the optical radiation distribution, and the optical integrator divides the optical radiation distribution irradiated onto the entrance pupil by the array lens and then superimposes the optical radiation distribution on the same position of the rear collimator, and the uniformity of the optical radiation distribution on each array element lens is definitely better than that of the optical radiation distribution of the whole entrance pupil, so that the amplified images are superimposed with each other to obtain uniform radiation distribution. However, the incident light beam using the optical integrator must be collimated, that is, a front collimating lens needs to be disposed behind the light source, including the existence of a rear collimating lens, so that the whole lighting system is larger, three light sources of RGB are usually required in the color projection module, and a light combining element needs to be additionally configured, so that the volume of the lighting system is further increased.

In the existing scheme, no matter a light homogenizing rod or an array lens integrator is used, a collimation or relay imaging system is needed, so that the system is complex, the procedures of assembling all devices together in a projection module are numerous, the assembly is complex, and high optical axis consistency is difficult to realize.

Therefore, the projection module of the prior art, especially the projection module applied to the micro projection system, has at least one of the following drawbacks: firstly, the overall size and the volume of the projection module are large, so that the size of an overall product cannot meet the requirement; secondly, the assembly relation among all components in the illumination system of the projection module needs to be accurately controlled, the assembly difficulty is increased, the error is increased along with the increase of the number of the components, and the consistency of front and rear optical axes is difficult to realize; thirdly, for different sizes of projection surfaces, the light divergence angles of the projection module in the prior art in the horizontal direction and the vertical direction are smaller, so that the uniform light effect in a certain direction is poor, the illumination area is not correct, or the left and right illumination is not uniform; fourth, the light condensing capability of the illumination system of the projection module in the prior art is weak, which causes the situations of light energy waste and low light efficiency.

Disclosure of Invention

One of the main advantages of the present invention is to provide a projection module and an illumination system thereof, wherein the overall size of the illumination system of the projection module is smaller, which is beneficial to miniaturization of the projection module.

Another advantage of the present invention is to provide a projection module and an illumination system thereof, wherein the projection module further includes a display chip and a light splitting component, the illumination system includes a light source, a condensing lens group, and a light homogenizing rod, wherein the light splitting component and a part of the light homogenizing rod form a PBS prism, so that a distance between an exit end of the light homogenizing rod and the display chip is smaller, thereby omitting a relay imaging system and reducing a volume of the projection module.

Another advantage of the present invention is to provide a projection module and an illumination system thereof, wherein the illumination system omits lens components, reduces system complexity, improves convenience of assembly, thereby reducing overall assembly errors of the projection module, and improves optical axis consistency.

The invention further provides a projection module and an illumination system thereof, wherein the condensing lens group is formed by combining one spherical mirror and one cylindrical mirror, and the problem that the light homogenizing effect in the H direction is poor due to smaller divergence angles of light rays in the V direction and the H direction, which are brought by the two spherical mirrors in the traditional scheme, is solved.

Another advantage of the present invention is to provide a projection module and an illumination system thereof, wherein a central ray of the light homogenizing rod and the light splitting component of the illumination system is perpendicularly incident to a chip center of a display chip, which is beneficial to improving uniformity of illumination of the illumination system.

The present invention further provides a projection module and an illumination system thereof, wherein the condensing lens assembly includes a first lens and a second lens, and the first lens is a cylindrical lens, so as to facilitate increasing a light divergence angle of the light homogenizing rod in an H direction, so as to increase a reflection number of the light in the H direction, and each reflection forms a virtual light source image to obtain a two-dimensional virtual light source matrix, and the more the number of virtual light sources is, the more uniform the light finally exits.

Another advantage of the present invention is to provide a projection module and an illumination system thereof, wherein the condensing lens group has better condensing effect, which greatly reduces light energy waste and improves light efficiency by more than 3 times.

Another advantage of the present invention is to provide a projection module and an illumination system thereof, wherein the projection module has a small size, which is beneficial to miniaturization of the apparatus.

In accordance with one aspect of the present invention, an illumination system of the present invention capable of achieving the foregoing and other objects and advantages includes:

A light source;

the light emitted by the light source is converged by the condensing lens group to form a condensing light path; and

the light beam enters the light homogenizing rod along the light condensing light path and is reflected by the light homogenizing rod to form at least one reflecting light path, wherein the light homogenizing rod comprises an incident end, an emergent end and a light homogenizing main body positioned between the incident end and the emergent end, and the light beam forms the reflecting light path through multiple reflections from the incident end, the light homogenizing main body and the emergent end along the light homogenizing light axis direction of the light homogenizing rod, wherein the incident end is provided with an incident end face, and the incident end face of the incident end is a chamfer formed at the end part of the incident end.

According to an embodiment of the invention, the light homogenizing rod is a cuboid glass rod with wide H direction and narrow V direction.

According to an embodiment of the present invention, the condensing lens set includes a first lens and a second lens, where the first lens is located at a front end of the second lens in a light incident direction, and the second lens is a cylindrical lens with optical power along a V direction, so that a light beam divergence angle along the H direction is greater than a light beam divergence angle along the V direction, and the number of reflection times of the light beam along the H direction is increased.

According to an embodiment of the invention, the first lens is a spherical mirror.

According to an embodiment of the present invention, an included angle of 45 ° is formed between the incident end face and the lower end face of the incident end.

According to an embodiment of the present invention, the light source has a light emitting surface, and the light emitting surface of the light source is parallel to the incident end surface of the incident end, wherein the condensing lens group has a condensing optical axis, and the condensing optical axis of the condensing lens group is perpendicular to the incident end surface of the light homogenizing rod.

According to an embodiment of the present invention, the exit end of the light homogenizing rod further has an exit end surface, wherein the exit end surface of the exit end is a chamfer formed at an end of the exit end, and the exit end surface of the exit end is parallel to the incident end surface of the incident end.

According to an embodiment of the present invention, the exit end of the light homogenizing rod further has an exit end surface, wherein the exit end surface of the exit end is a chamfer formed at an end of the exit end, and the exit end surface of the exit end is perpendicular to the incident end surface of the incident end.

According to another aspect of the present invention, there is further provided a projection module, including:

An illumination system, wherein the illumination system comprises a light source, a condensing lens group and a light homogenizing rod, wherein the condensing lens group is arranged between the light source and the light homogenizing rod;

a display chip; and

the display chip and the light splitting component are arranged in the light emergent direction of the emergent end of the light homogenizing rod, the light splitting component is glued to the emergent end, and light with image information reflected by the display chip forms a projection light path through the light splitting component, wherein the projection light path extends obliquely towards the direction opposite to the light homogenizing optical axis of the light homogenizing rod so as to reduce the length of the projection module along the direction of the light homogenizing optical axis of the light homogenizing rod.

According to an embodiment of the present invention, the light-emitting end further has a light-transmitting area, and the light-splitting component is glued to the light-transmitting area of the light-emitting end, wherein the light-transmitting area is located on an upper end surface of the light-homogenizing rod, and the projected light path formed by the light-splitting component extends obliquely upwards in a direction opposite to the light-homogenizing optical axis of the light-homogenizing rod.

According to an embodiment of the present invention, the light-emitting end further has a light-transmitting area, and the light-splitting component is glued to the light-transmitting area of the light-emitting end, wherein the light-transmitting area is located at a lower end face of the light-homogenizing rod, and the projected light path formed by the light-splitting component extends obliquely downward in a direction opposite to the light-homogenizing optical axis of the light-homogenizing rod.

According to an embodiment of the present invention, the optical system further includes a projection lens, wherein the projection lens is disposed at the light emitting end of the beam splitter along the projection light path.

According to an embodiment of the present invention, the light splitting part includes a prism having a prism incident end face and a prism exit end face, and a light splitting film integrally formed on the prism incident end face of the prism, through which imaging light is incident to the prism, and exits from the prism exit end face of the prism to the projection lens.

According to an embodiment of the present invention, the incident end of the light homogenizing rod has an incident end surface, wherein the incident end surface is the chamfer surface formed on the incident end, and the light source and the condensing lens group are located obliquely above the light homogenizing rod, so as to reduce the length of the projection module along the light homogenizing optical axis direction of the light homogenizing rod.

According to an embodiment of the present invention, the incident end face of the incident end forms an angle of 45 ° with the lower end face, and the condensing lens group has a condensing optical axis, and the condensing optical axis is perpendicular to the incident end face of the light homogenizing rod.

According to an embodiment of the present invention, the condensing lens set includes a first lens and a second lens, wherein the first lens is located at a front end of the second lens in a light incident direction, and the first lens and the second lens are spherical mirrors.

According to an embodiment of the present invention, the condensing lens group includes a first lens and a second lens, wherein the first lens is located at a front end of the second lens in a light incident direction, the first lens is a spherical lens, the second lens is a cylindrical lens, and the second lens has a V-direction optical power.

According to an embodiment of the invention, the light homogenizing rod is a cuboid glass rod with wide H direction and narrow V direction.

According to another aspect of the present invention, there is further provided a projection module, including:

a lighting system, wherein the lighting system comprises:

the lighting system of any one of the above;

the light splitting component is arranged at the emergent end of the light homogenizing rod, and selectively transmits or reflects part of light to the display chip, and the display chip reflects the light with image information.

According to an embodiment of the invention, the first lens is a spherical mirror.

According to an embodiment of the invention, the light homogenizing rod is a cuboid glass rod with wide H direction and narrow V direction.

According to an embodiment of the present invention, the condensing lens set includes a first lens and a second lens, where the first lens is located at a front end of the second lens in a light incident direction, and the second lens is a cylindrical lens with optical power along a V direction, so that a light beam divergence angle along the H direction is greater than a light beam divergence angle along the V direction, and the number of reflection times of the light beam along the H direction is increased.

According to an embodiment of the present invention, an included angle of 45 ° is formed between the incident end face and the lower end face of the incident end.

According to an embodiment of the present invention, the light source has a light emitting surface, and the light emitting surface of the light source is parallel to the incident end surface of the incident end, wherein the condensing lens group has a condensing optical axis, and the condensing optical axis of the condensing lens group is perpendicular to the incident end surface of the light homogenizing rod.

According to an embodiment of the present invention, the exit end of the light homogenizing rod further has an exit end surface, wherein the exit end surface of the exit end is a chamfer formed at an end of the exit end, and the exit end surface of the exit end is parallel to the incident end surface of the incident end.

According to an embodiment of the present invention, the exit end of the light homogenizing rod further has an exit end surface, wherein the exit end surface of the exit end is a chamfer formed at an end of the exit end, and the exit end surface of the exit end is perpendicular to the incident end surface of the incident end.

According to an embodiment of the invention, the light splitting component is glued to the outgoing end, and the light with the image information reflected by the display chip forms a projection light path through the light splitting component, wherein the projection light path extends obliquely in a direction opposite to the dodging optical axis of the dodging rod so as to reduce the length of the projection module along the dodging optical axis direction of the dodging rod.

According to an embodiment of the present invention, the light-emitting end further has a light-transmitting area, and the light-splitting component is glued to the light-transmitting area of the light-emitting end, wherein the light-transmitting area is located on an upper end surface of the light-homogenizing rod, and the projected light path formed by the light-splitting component extends obliquely upwards in a direction opposite to the light-homogenizing optical axis of the light-homogenizing rod.

According to an embodiment of the present invention, the light-emitting end further has a light-transmitting area, and the light-splitting component is glued to the light-transmitting area of the light-emitting end, wherein the light-transmitting area is located at a lower end face of the light-homogenizing rod, and the projected light path formed by the light-splitting component extends obliquely downward in a direction opposite to the light-homogenizing optical axis of the light-homogenizing rod.

According to an embodiment of the present invention, the optical system further includes a projection lens, wherein the projection lens is disposed at the light emitting end of the beam splitter along the projection light path.

According to an embodiment of the present invention, the light splitting part includes a prism having a prism incident end face and a prism exit end face, and a light splitting film integrally formed on the prism incident end face of the prism, through which imaging light is incident to the prism, and exits from the prism exit end face of the prism to the projection lens.

Further objects and advantages of the present invention will become fully apparent from the following description and the accompanying drawings.

These and other objects, features and advantages of the present invention will become more fully apparent from the following detailed description and accompanying drawings.

Drawings

Fig. 1 is a schematic structural diagram of a projection module according to the prior art.

Fig. 2 is a schematic view of an optical path of the projection module of the prior art.

FIG. 3 is a schematic diagram of a prior art compact optical engine system based on a micro-display chip.

Fig. 4 is a schematic perspective view of a projection module according to a first preferred embodiment of the invention.

Fig. 5 is a schematic plan view of the projection module according to the first preferred embodiment of the present invention.

Fig. 6 is a schematic structural diagram of the projection module according to the first preferred embodiment of the present invention.

Fig. 7 is a schematic view illustrating an optical path structure of the projection module along the V direction according to the first preferred embodiment of the present invention.

Fig. 8A is a schematic view illustrating an optical path structure of the projection module along the H direction according to the first preferred embodiment of the present invention.

Fig. 8B is a schematic view of another optical path structure of the projection module along the H direction according to the first preferred embodiment of the present invention.

Fig. 9 is a schematic structural view of another alternative implementation of the projection module according to the first preferred embodiment of the present invention.

Fig. 10 is a schematic structural view of another alternative implementation of the projection module according to the first preferred embodiment of the present invention.

Detailed Description

The following description is presented to enable one of ordinary skill in the art to make and use the invention. The preferred embodiments in the following description are by way of example only and other obvious variations will occur to those skilled in the art. The basic principles of the invention defined in the following description may be applied to other embodiments, variations, modifications, equivalents, and other technical solutions without departing from the spirit and scope of the invention.

It will be appreciated by those skilled in the art that in the present disclosure, the terms "longitudinal," "transverse," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," etc. refer to an orientation or positional relationship based on that shown in the drawings, which is merely for convenience of description and to simplify the description, and do not indicate or imply that the apparatus or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore the above terms should not be construed as limiting the present invention.

It will be understood that the terms "a" and "an" should be interpreted as referring to "at least one" or "one or more," i.e., in one embodiment, the number of elements may be one, while in another embodiment, the number of elements may be plural, and the term "a" should not be interpreted as limiting the number.

Referring to fig. 4 to 8B of the drawings, a projection module according to a first preferred embodiment of the present invention is illustrated in the following description. The projection module comprises an illumination system 10, a display chip 20 arranged in the light emergent direction of the illumination system and a light splitting component 30, wherein the illumination light emitted by the illumination system 10 selectively reflects part of the light to the display chip 20 through the light splitting component 30, and then the light modulated by the display chip 20 forms light with an image and is projected outwards through the light splitting component. The lighting system 10 includes a light source 11, a condensing lens group 12 and a light homogenizing rod 13, wherein the light emitted from the light source 11 is projected to the condensing lens group 12, and is converged by the condensing lens group 12 to form a condensing light path 120; the light enters the light homogenizing rod 13 along the light condensing optical path 120, and is reflected by the light homogenizing rod 13 and forms at least one reflecting optical path 130 in the light homogenizing rod 13; the light rays are emitted to the display chip 20 or the light splitting component 30 along the reflection light path 130, and form illumination spots on the surface of the display chip 20.

As shown in fig. 4, the projection module further includes at least one projection lens 40, wherein the projection lens 40 is disposed on the light-emitting side of the light-splitting component 30, and the image light emitted by the display chip 20 is projected outwards through the light-splitting component 30 and the projection lens 40 to form a projection pattern.

In detail, the light source 11 is used for illumination, and the light source 11 emits illumination light. Preferably, in this preferred embodiment of the invention, the light source 11 is implemented as an LED, wherein the light source emits light at an angle of around 120 °. It is understood that the type of light source and the angle of the light rays are herein given by way of example only and not by way of limitation.

The condensing lens group 12 of the illumination system 10 has a condensing optical axis O ₁ And is taken along the condensing optical axis O by the condensing lens group 12 ₁ Light emitted from the light source 11 is condensed and forms the condensed light path 120. The condensing lens set 12 includes a first lens 121 and a second lens 122, wherein the first lens 121 is located at a front end of the second lens 122 in a light incident direction, that is, light emitted from the light source 11 is converged by the first lens 121 to the second lens 122, and then converged by the second lens 122 to form the condensing light path 120. Preferably, in the preferred embodiment of the present invention, the central ray of the condensing lens group 12 is along the condensing optical axis O ₁ The direction of the light is emitted from the condensing lens group 12 to the light homogenizing rod 13.

Fig. 8A and 8B illustrate two different embodiments of the condensing lens group 12 of the present invention. As shown in fig. 8A, the first lens 121a and the second lens 122a of the condensing lens group 12 are spherical mirrors, so that the condensing lens group 12 has optical powers in the V direction (horizontal direction) and the H direction (vertical direction), that is, the condensing lens group 12 has the same converging and diverging effects in the V direction and the H direction. As shown in fig. 8B, the first lens 121B of the condensing lens group 12 is a spherical lens, and the second lens 122B of the condensing lens group 12 is a cylindrical lens, and since the cylindrical lens has optical power in the V direction and has no optical power in the H direction, the divergence angle of the light in the H direction is larger than that in the V direction, so as to increase the reflection times of the light in the H direction. It will be appreciated that each reflection forms a virtual light source image to obtain a two-dimensional virtual light source matrix, and that the greater the number of virtual light sources, the more uniform the light rays finally emitted.

Correspondingly, if two spherical mirrors are adopted as the condensing lens group, the divergence angles of the light rays in the V direction and the H direction are consistent, and the smaller the divergence angle of the light rays in the V direction is, the better the divergence angle of the light rays in the H direction is, the smaller the divergence angle of the light rays in the H direction is, the less the reflection times of the light rays on the two side walls of the light homogenizing rod are, and the light homogenizing effect in the H direction is poor.

The display chip 20 of the projection module has a chip reflecting surface 201, wherein the chip reflecting surface 201 faces the light homogenizing rod 13 of the illumination system 10, and the chip reflecting surface 201 reflects the image light to the light splitting component 30. It should be noted that in the preferred embodiment of the present invention, the chip reflecting surface 201 of the display chip 20 is a rectangular surface. Preferably, the chip reflecting surface 201 of the display chip 20 is 16: 9. It will be appreciated by those skilled in the art that the specific shape and proportions of the chip reflecting surface 201 of the display chip 20 are given by way of example only and not limitation, and that in alternative embodiments of the present invention, the shape and size of the display chip 20 may be adjusted as desired.

Preferably, the light homogenizing rod 13 is a square rod with a wide H direction and a narrow V direction, so that the uniform illumination light spot modulated by the light homogenizing rod 13 is close to the shape of the display chip, and the light energy waste is reduced. Accordingly, in the preferred embodiment of the present invention, the first lens 121 of the condensing lens group 12 is a spherical lens, and the second lens 122 is a cylindrical lens, and since the cylindrical lens has optical power in the V direction and has no optical power in the H direction, the divergence angle of the light in the H direction is larger than that in the V direction, so as to increase the number of reflections of the light in the H direction, each reflection forms a virtual light source image to obtain a two-dimensional virtual light source matrix, and the more virtual light sources, the more the number of virtual light sources, the more uniform the finally outgoing light.

It should be noted that, in the preferred embodiment of the present invention, the light receiving capability of the display chip 20 is generally about 60 °, and the condensing lens set 12 of the present application has better condensing effect compared to the prior art, and the condensing lens set 12 can receive light to 50 ° to 70 °, which greatly reduces light energy waste and improves light efficiency by more than 3 times.

As shown in fig. 4 to 8B, the light homogenizing rod 13 of the illumination system 10 is a rectangular parallelepiped glass rod. Preferably, in the preferred embodiment of the present invention, the refractive index of the material of the light homogenizing rod 13 ranges from 1.5 to 1.7. The light-homogenizing rod 13 comprises an incident end 131, an emergent end 132 and a homogenizing body 133 between the incident end 131 and the emergent end 132, wherein the light enters the incident end 131 of the light-homogenizing rod 13 along the condensing light path 120, and the light is along a homogenizing optical axis O of the light-homogenizing rod 13 ₂ The direction is reflected for multiple times by the incident end 131, the light homogenizing body 133 and the emergent end 132 in sequence to form the reflected light path 130, and then is emergent to the display chip 20 by the emergent end 132.

It should be noted that each reflection of the light forms a virtual light source image, and a two-dimensional virtual light source matrix is obtained based on the chip reflecting surface 201 of the display chip 20, so that the more virtual light sources, the more uniform the light is finally emitted. Each time the light beam passes through the light homogenizing rod 13, the light beam is reflected to form a reflecting light path 130. Therefore, the number of reflections of the light rays within the light bar 13 directly determines the illuminance of the illumination system 10.

The light-homogenizing rod 13 further has an upper end face 134 and a lower end face 135 opposite to the upper end face 134, wherein the upper end face 134 and the lower end face 135 of the light-homogenizing rod 13 are reflective surfaces facing each other, and a part of light is reflected by each other between the upper end face 134 and the lower end face 135 of the light-homogenizing rod 13 to form a plurality of V-direction reflective light paths 130a along the V-direction. The light-homogenizing rod 13 further has a left end face 136 and a right end face 137 forward opposite to the left end face 136, wherein the left end face 136 and the right end face 137 of the light-homogenizing rod 13 are reflective surfaces facing each other, and a part of light is reflected by each other between the left end face 136 and the right end face 137 of the light-homogenizing rod 13 to form a plurality of H-direction reflective light paths 130b along the H-direction. It is understood that the V-direction reflection optical path 130a and the H-direction reflection optical path 130b are at least part of optical paths constituting the reflection optical path 130.

The incident end 131 of the light homogenizing rod 13 is further provided with an incident end face 1310, and the light converged by the condensing lens group 12 is incident to the light homogenizing rod 13 through the incident end face 1310 of the incident end 131. The incident end surface 1310 of the incident end 131 is a chamfer formed at the end of the incident end 131, wherein the light collected by the condensing lens group 12 is incident through the incident end surface 1310 of the incident end 131, is refracted to each end surface (the upper end surface 134, the lower end surface 135, the left end surface 136 or the right end surface 137) of the light homogenizing rod 13, and is reflected between each end surface to form the reflected light path 130.

It should be noted that the condensing optical axis O of the condensing lens group 12 ₁ And the dodging optical axis O of the dodging rod 13 ₂ Crossing or interleaving each other. In other words, in the preferred embodiment of the present invention, the light collected by the condensing lens group 12 is incident on the incident end face 1310 of the light homogenizing rod 13 obliquely downward along the condensing light path 120, that is, the light source 11 and the condensing lens group 12 are located obliquely above the light homogenizing rod 13, which is beneficial to reduce the projection module along the light homogenizing optical axis O ₂ The length of the direction is further beneficial to miniaturization of the projection module.

Preferably, in the preferred embodiment of the present invention, the incident end face 1310 of the incident end 131 forms an angle of 45 ° with the lower end face 135. More preferably, the condensing optical axis O of the condensing lens group 12 ₁ Perpendicular to the incident end face 1310 of the light homogenizing rod 13, that is, the central light converged by the condenser lens group 12 is perpendicularly incident to the incident end face 1310 of the light homogenizing rod 13, so as to increase lightThe number of reflections in the light rod 13, i.e. the number of reflection light paths 130 is increased, is beneficial for the light homogenizing effect of the light rod 13. The light source 11 of the illumination system 10 has a light emitting surface 110, wherein the light source 11 emits illumination light from the light emitting surface 110, the light emitting surface 110 of the light source 11 is parallel to the incident end surface 1310 of the incident end 131 of the light homogenizing rod 13, and the condensing optical axis O of the condensing lens group 12 ₁ Perpendicular to the incident end surface 1310 of the light homogenizing rod 13, so that the central light can be incident perpendicular to the incident end surface, the reflection times of the light in the V direction in the light homogenizing rod are maximized, and the light homogenizing effect of the lighting system 10 in the V direction is improved.

As shown in fig. 4 to 6, the emitting end 132 of the light bar 13 has an emitting end surface 1320, wherein the emitting end surface 1320 of the emitting end 132 is formed at an end of the emitting end 132, and the chip reflecting surface 201 of the display chip 20 is opposite to the emitting end surface 132 of the light bar 13. The reflected light is emitted to the display chip 20 through the emitting end surface 1320 of the emitting end 132 of the light homogenizing rod 13. Preferably, the chip reflecting surface 201 of the display chip 20 is parallel to the emitting end surface 132 of the light homogenizing rod 13. Preferably, the exit end surface 1320 of the light homogenizing rod 13 is a chamfer formed at the exit end 132, and the exit end surface 1320 is parallel to the entrance end surface 1310 of the entrance end 131.

The light-splitting member 30 is provided at the exit end 132 of the light-homogenizing rod 13, and the light-splitting member 30 has a selective action on light rays, which can selectively transmit and/or reflect part of the light rays. The exit end 132 of the light homogenizing rod 13 is further provided with a light-transmitting area 1321, wherein the reflected light can pass through the light-transmitting area 1321 of the exit end 132, and the light-splitting component 30 is disposed in the light-transmitting area 1321 of the exit end 132. Preferably, in the preferred embodiment of the present invention, the light splitting component 30 is adhered to the light transmitting region 1321 of the exit end 132 of the light homogenizing rod 13, and the light reflected by the light homogenizing rod 13 reaches the light splitting component 30 through the light transmitting region 1321 of the exit end 132, and part of the light is selectively reflected and/or transmitted by the light splitting component 30. More preferably, the light-transmitting area 1321 of the exit end 132 of the light-homogenizing rod 13 is located on the upper end face 134 of the light-homogenizing rod 13.

The light-splitting member 30 includes a prism 31 and a light-splitting film 32, wherein the light-splitting film 32 is provided to the prism 31, and a part of light is selectively reflected and/or transmitted by the light-splitting film 32. Preferably, in the preferred embodiment of the present invention, the light splitting film 32 is a PBS film, which is capable of selectively projecting P light and reflecting S light.

More preferably, the prism 31 is a right angle prism, the prism 31 has a prism entrance face 311 and a prism exit face 312, wherein the light splitting film 32 is integrally formed on the prism entrance face 311 of the prism 31. The imaging light emitted from the display chip 20 is incident on the prism 31 through the prism incident end face 311 of the prism 31, and is emitted from the prism emitting end face 312 of the prism 31 to the projection lens 40. It should be noted that the prism incident end face 311 of the prism 31 is an inclined plane of the right-angle prism, that is, a polarizing beam splitter (PBS film) is coated on the inclined plane of the prism 31 to form the beam splitter 30.

The light reflected by the light-homogenizing rod 13 forms a light-splitting path 320 under the action of the light-splitting film 32 from the light-transmitting region 1321 of the light-emitting end 132, wherein the P light is transmitted, and the S light is reflected by the light-splitting film 32 to the display chip 20 at the end of the light-homogenizing rod 13. The S light modulated by the display chip 20 is changed into P light, the imaging light with image information is reflected by the display chip 20 to the light splitting film 32, the light splitting film 32 transmits the imaging light with image information to the projection lens 40, and the projection lens 40 projects the imaging light outwards to form a projection image.

Taking the central light as an example, when the exit end 132 of the light homogenizing rod 13 reaches the upper end face 134 of the light homogenizing rod 13, the central light forms an included angle of 45 ° with the light transmitting area 1321, and under the action of the light splitting film 32, the P light is transmitted, the S light is reflected and vertically incident into the display chip 20, the S light is modulated by the display chip 20 and becomes the P light, the P light is reflected by the micro-mirror in the display chip 20 to the light splitting film 32, and the P light is transmitted into the projection lens to form a final image.

The light beam with imaging information, which is modulated by the display chip 20, passes through the exit end 132 of the light homogenizing rod 13 and penetrates through the prism 31 and the light splitting film 32 of the light splitting component 30 to form a projection light path 321, and the light beam with imaging information passes through the projection light path 321 to the projection lens 40. It should be noted that, in the preferred embodiment of the present invention, the projection light path 321 formed by the transmission of the light splitting film 32 is directed opposite to the dodging optical axis O ₂ The projection lens 40 is located obliquely above the beam splitter 30 along the projection optical path 321. Therefore, in the preferred embodiment of the present invention, the position of the projection lens 40 is adjusted by a specific light path design, i.e. the direction of the projection light path 321, so as to reduce the projection module along the dodging optical axis O ₂ The length in the direction is beneficial to miniaturization of the projection module.

In the prior art, the incident S polarized light irradiates the display chip 20 after being reflected by the PBS prism, when the applied voltage of a certain pixel of the liquid crystal layer is 0, the input S polarized light passes through the liquid crystal layer, the polarization direction is not deflected, the input S polarized light reaches the bottom and is reflected back to output S polarized light, the S polarized light is reflected by the PBS prism beam splitting component, the S polarized light returns to the original path and cannot enter the transmission light path, the light output is zero, and the pixel presents a "dark state". When voltage is applied to the outside of the pixel, the input S polarized light passes through the liquid crystal layer, the polarization direction deflects, the light reaches the bottom and is reflected back to output P polarized light, the light directly passes through the PBS prism beam splitting component and enters the transmission light path, and the pixel presents a bright state and forms images on a screen. The PBS prism beam splitting component is formed by gluing two prisms, wherein one prism surface is plated with a PBS film, when natural light enters the PBS film, P light is transmitted, and S light is reflected.

It should be noted that, in the preferred embodiment of the present invention, the light splitting component 30 is glued to the upper end face 134 of the light homogenizing rod 13, and the light splitting component 30 is located at the exit end 132, and the light splitting component 30 and at least part of the exit end 132 of the light homogenizing rod 13 form a PBS prism. In other words, a part of the structure of the PBS prism is integrally formed at the exit end 132 of the light bar 13. By the mode, the distance between the emergent end of the light homogenizing rod and the display chip is reduced, so that larger uniformity can be maintained when uniform illumination of the emergent end face of the light homogenizing rod is projected to the display chip. Meanwhile, the scheme omits a relay lens, eliminates the assembly process among the light homogenizing rod, the relay lens and the PBS prism, improves the preparation efficiency, reduces the assembly error, and further improves the consistency of the optical axis of the projection system.

In other words, in the preferred embodiment of the present invention, the light homogenizing rod 13 and the light splitting part 30 are designed to ensure that the central light is perpendicularly incident to the center of the display chip 20, thereby reducing the occurrence of uneven illumination areas or uneven illuminance. In addition, under the condition that the lengths of the light homogenizing bars 13 are the same, the condensing lens group 12 is located above the inclination of the light homogenizing bars 13, and the light splitting component 30 and the projection lens 40 are located above the light homogenizing bars 13, so that the longitudinal lengths of the light splitting component and the projection lens are reduced to a certain extent, the size of the projection module provided by the application is smaller, and equipment miniaturization is facilitated.

Referring to fig. 9 of the drawings, a projection module according to the first preferred embodiment of the present invention is illustrated in the following description. The projection module comprises an illumination system 10, a display chip 20 arranged in the light emergent direction of the illumination system and a light splitting component 30, wherein the illumination light emitted by the illumination system 10 selectively reflects part of the light to the display chip 20 through the light splitting component 30, and then the light modulated by the display chip 20 forms light with an image and is projected outwards through the light splitting component. In this preferred embodiment of the present invention, the structure and function of the illumination system 10, the display chip 20 and the light splitting component 30 are substantially the same as those of the first preferred embodiment described above, except that the location of the display chip 20 is used to better match the overall structural design of the near-eye display device.

In detail, the prism 31 of the light-splitting component 30 is located at the upper end of the light-homogenizing rod 13, and the prism 31 further has a light-transmitting surface 313, wherein the display chip 20 is facing the light-transmitting surface 313 of the prism 31. The light-transmitting surface 313 of the prism 31 is adjacent to the prism exit end surface 312, a portion of the light selectively transmitted through the light-splitting film 32 can pass through the light-transmitting surface 313 of the prism 31, the image light with display information reflected by the display chip 20 enters the prism 31 through the light-transmitting surface 313 of the prism 31, and then the light-splitting film 32 reflects the image light to the prism exit end surface 312. Unlike the first preferred embodiment, the light splitting film 32 of the light splitting member 30 selectively reflects and transmits a part of the light, and forms a light splitting path 320 in the prism 31 from the transmitted part of the light.

Preferably, in the preferred embodiment of the present invention, the chip reflecting surface 201 of the display chip 20 is parallel to the light transmitting surface 313 of the prism 31. It should be noted that, in the preferred embodiment of the present invention, the projection light path 321 formed by the reflection of the light splitting film 32 is directed opposite to the dodging optical axis O ₂ The projection lens 40 is located obliquely above the beam splitter 30 along the projection optical path 321. Therefore, in the preferred embodiment of the present invention, the position of the projection lens 40 is adjusted by a specific light path design, i.e. the direction of the projection light path 321, so as to reduce the projection module along the dodging optical axis O ₂ The length in the direction is beneficial to miniaturization of the projection module.

A projection module according to the above-described first preferred embodiment of the present invention is illustrated in the following description with reference to fig. 10 of the drawings accompanying the present invention. The projection module comprises an illumination system 10, a display chip 20 arranged in the light emergent direction of the illumination system, a light splitting component 30 and at least one projection lens 40, wherein the illumination light emitted by the illumination system 10 selectively reflects part of the light to the display chip 20 through the light splitting component 30, and then the light modulated by the display chip 20 to form light with an image is projected outwards through the light splitting component to form an image. In this preferred embodiment of the present invention, the structure and function of the display chip 20 and the light splitting means 30 are substantially the same as those of the first preferred embodiment described above, except that the structure of the light homogenizing rod 13 of the illumination system 10 and the positions of the light splitting means 30 and the projection lens 40 are better matched to the overall structural design of the near-eye display device.

In detail, the exit end 132 of the light rod 13 has a light-transmitting region 1321A, wherein the light-transmitting region 1321A is formed on the lower end surface 135 of the light rod 13, and the light-splitting component 30 is glued to the light-transmitting region 1321A of the exit end 132 of the light rod 13. The projection lens 40 is located at the light emitting end of the beam splitter 30, that is, the imaging light is projected to the projection lens 40 through the prism 31 of the beam splitter 30.

The exit end 132 of the light bar 13 further has an exit end surface 1320A, and the display chip 20 is opposite to the exit end surface 1320A. Unlike the first preferred embodiment, the exit end surface 1320A is a chamfer, and the plane of the chamfer of the exit end surface 1320A is perpendicular to the plane of the incident end surface 1310 of the incident end 131, i.e. the exit end surface 1320A is a chamfer inclined from top to bottom, so as to guide the imaging light downwards from the display chip 20 to the beam splitting component 30.

It should be noted that, in the preferred embodiment of the present invention, the light beam with the imaging information, which is modulated by the display chip 20, passes through the exit end 132 of the light homogenizing rod 13 and passes through the prism 31 and the light splitting film 32 of the light splitting component 30 to form a projection light path 321A, and the light beam with the imaging information passes through the projection light path 321A to the projection lens 40. The projection light path 321A formed by the transmission of the light splitting film 32 is directed opposite to the dodging optical axis O ₂ The projection lens 40 is located obliquely downward of the spectroscopic member 30 along the projection optical path 321A. Thus, in this preferred embodiment of the invention, the light path is designed specifically, i.e. the throwThe position of the projection lens 40 is adjusted along the direction of the light-emitting path 321A, which is favorable for reducing the projection module along the dodging optical axis O ₂ The length in the direction is beneficial to miniaturization of the projection module.

It will be appreciated by persons skilled in the art that the embodiments of the invention described above and shown in the drawings are by way of example only and are not limiting. The objects of the present invention have been fully and effectively achieved. The functional and structural principles of the present invention have been shown and described in the examples and embodiments of the invention may be modified or practiced without departing from the principles described.

Claims (16)

1. A lighting system, comprising:

a light source;

the light emitted by the light source is converged by the condensing lens group to form a condensing light path; and

the light beam enters the light homogenizing rod along the light condensing light path and is reflected by the light homogenizing rod to form at least one reflecting light path, wherein the light homogenizing rod comprises an incident end, an emergent end and a light homogenizing main body positioned between the incident end and the emergent end, and the light beam forms the reflecting light path through multiple reflections from the incident end, the light homogenizing main body and the emergent end along the light homogenizing light axis direction of the light homogenizing rod, wherein the incident end is provided with an incident end face, and the incident end face of the incident end is a chamfer formed at the end part of the incident end.

2. The illumination system of claim 1, wherein the light homogenizing rod is a rectangular parallelepiped glass rod having a wide H-direction and a narrow V-direction.

3. The illumination system according to claim 1 or 2, wherein the condensing lens group includes a first lens and a second lens, the first lens being located at a front end of the second lens in a light incident direction, wherein the second lens is a cylindrical mirror having optical power in a V direction so that light rays are larger in an H direction than a light ray divergence angle in the V direction, increasing the number of reflection times of the light rays in the H direction.

4. The illumination system of claim 3, wherein the first lens is a spherical mirror.

5. The illumination system of claim 4, wherein the entrance end face of the entrance end is at a 45 ° angle to the lower end face.

6. The illumination system of claim 5, wherein the light source has a light emitting surface, the light emitting surface of the light source being parallel to the incident end face of the incident end, wherein the condenser lens group has a condenser optical axis, the condenser optical axis of the condenser lens group being perpendicular to the incident end face of the light homogenizing rod.

7. The illumination system of claim 6, wherein the exit end of the light bar further has an exit end face, wherein the exit end face of the exit end is a chamfer formed at an end of the exit end, and the exit end face of the exit end is parallel to the entrance end face of the entrance end.

8. The illumination system of claim 6, wherein the exit end of the light bar further has an exit end face, wherein the exit end face of the exit end is a chamfer formed at an end of the exit end, and the exit end face of the exit end is perpendicular to the entrance end face of the entrance end.

9. A projection module, comprising:

an illumination system, wherein the illumination system comprises a light source, a condensing lens group and a light homogenizing rod, wherein the condensing lens group is arranged between the light source and the light homogenizing rod;

a display chip; and

the display chip and the light splitting component are arranged in the light emergent direction of the emergent end of the light homogenizing rod, the light splitting component is glued to the emergent end, and light with image information reflected by the display chip forms a projection light path through the light splitting component, wherein the projection light path extends obliquely towards the direction opposite to the light homogenizing optical axis of the light homogenizing rod so as to reduce the length of the projection module along the direction of the light homogenizing optical axis of the light homogenizing rod.

10. The projection module of claim 9, wherein the exit end further has a light-transmitting region, the light-splitting component is glued to the light-transmitting region of the exit end, wherein the light-transmitting region is located on an upper end face of the light-homogenizing rod, and wherein the projected light path formed by the light-splitting component extends obliquely upward in a direction opposite to the light-homogenizing optical axis of the light-homogenizing rod.

11. The projection module of claim 9, wherein the exit end further has a light-transmitting region, the light-splitting component is glued to the light-transmitting region of the exit end, wherein the light-transmitting region is located at a lower end face of the light-homogenizing rod, and wherein the projected light path formed by the light-splitting component extends obliquely downward in a direction opposite to the light-homogenizing optical axis of the light-homogenizing rod.

12. The projection module of claim 10 or 11, further comprising a projection lens, wherein the projection lens is disposed at the light exit end of the light splitting component along the projection light path.

13. The projection module of claim 12, wherein the light splitting component comprises a prism having a prism entrance face and a prism exit face, and a light splitting film integrally formed on the prism entrance face of the prism, the imaging light being incident on the prism through the prism entrance face of the prism and exiting from the prism exit face of the prism to the projection lens.

14. The projection module of claim 12, wherein the incident end of the light bar has an incident end surface, wherein the incident end surface is the chamfer surface formed on the incident end, and the light source and the condenser lens group are positioned obliquely above the light bar to reduce the length of the projection module along the light-homogenizing optical axis direction of the light bar.

15. A projection module, comprising:

the lighting system of any one of claims 1 to 8;

the light splitting component is arranged at the emergent end of the light homogenizing rod, and selectively transmits or reflects part of light to the display chip, and the display chip reflects the light with image information.

16. The projection module of claim 15, wherein the condensing lens group comprises a first lens and a second lens, the first lens is positioned at the front end of the second lens in the light incident direction, wherein the second lens is a cylindrical lens with optical power along the V direction, so that the light divergence angle of the light along the H direction is larger than the light divergence angle along the V direction, and the number of reflections of the light along the H direction is increased.

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