CN118409471A - Compact DLP projection optical engine - Google Patents

Abstract

The application belongs to the field of optical projection, and particularly relates to a compact DLP projection optical engine, which comprises a light source assembly, wherein the light source assembly comprises a first light source for emitting first light, a second light source for emitting second light and a third light source for emitting third light; the light mixing assembly comprises a first dichroic mirror, a second dichroic mirror and a reflecting mirror which are sequentially arranged on a light emitting path of the light source assembly, wherein the first dichroic mirror only reflects first light, the second dichroic mirror only reflects second light, the third light passes through the first dichroic mirror and the second dichroic mirror and then is reflected by the reflecting mirror, and the first light, the second light and the third light are coaxial after being reflected by the light mixing assembly; the DLP micro-display panel is used for receiving light and reflecting the light modulated by the digital image; and the projection component is used for receiving the reflected light of the DLP micro-display panel and projecting and emitting the reflected light. The application has the effect of miniaturization of the projection equipment.

Description

Compact DLP projection optical engine

Technical Field

The application relates to the field of optical projection, in particular to a compact DLP projection optical engine.

Background

An optical projection engine generally includes a light source, a microdisplay panel, and a projection assembly, wherein R, G, B a mixed-light illumination system uniformly illuminates the digital microdisplay panel and then projects a color image of the digital microdisplay panel onto a wall surface or display medium through the projection assembly.

Generally, a high optical efficiency optical projection engine architecture includes three optical channels, each containing a color light source and a set of collimating optics, making the overall device large in size, unsuitable for applications such as near-eye projection systems like AR/VR and head-mounted displays, embedded projection displays like smart home appliances and robotic projection displays, and small projection lamps.

To meet the compact size requirements of optical projection engines for some of the above application scenarios, a two-channel or single-channel projection engine architecture is an alternative arrangement. By adopting a single-channel projection engine architecture, an RGB light source is packaged on the same substrate, and after independent light mixing and homogenizing components are removed through the same collimating optical channel, the projection light engine can be made compact, but the illumination and color uniformity of illumination spots are relatively poor, and the efficiency of the projection light engine is relatively low. Therefore, in the field of miniature projection applications, there is a need for a projection optical engine that reduces the overall size of the projection device while ensuring the screen illumination, color uniformity, and optical efficiency of the projection optical engine.

Disclosure of Invention

In order to solve the above problems, the present application provides a compact DLP projection optical engine that makes the structure and size of a projection apparatus compact.

The application provides a compact DLP projection optical engine, which adopts the following technical scheme:

A compact DLP projection optical engine comprising:

The light source assembly comprises a first light source for emitting first light, a second light source for emitting second light and a third light source for emitting third light, wherein the first light source, the second light source and the third light source are packaged on the same substrate;

The light mixing assembly comprises a first dichroic mirror, a second dichroic mirror and a reflecting mirror which are sequentially arranged on a light emitting path of the light source assembly, wherein the first dichroic mirror only reflects the first light, the second dichroic mirror only reflects the second light, the third light passes through the first dichroic mirror and the second dichroic mirror and then is reflected by the reflecting mirror, and the first light, the second light and the third light are coaxial after being reflected by the light mixing assembly;

the DLP micro-display panel is used for receiving light rays and reflecting the light rays modulated by the digital image, and coaxial light rays formed by the first light rays, the second light rays and the third light rays form uniform imaging illumination light spots on the DLP micro-display panel; and

And the projection component is used for receiving the reflected light rays of the DLP micro-display panel and projecting and exiting.

Through adopting above-mentioned technical scheme, first light, second light and third light mix in mixing the optical subassembly and form coaxial light beam, coaxial light beam shines to DLP micro-display panel, reflect out the output light beam that carries image information, output light beam is by projection assembly output projection, light only just forms even formation of image illumination facula on DLP micro-display panel after the reflection light path in mixing the optical subassembly after sending from the light source subassembly, need not to carry out even light by compound eye structure etc. and carry out the structure of modulation to the light and retrench, projection engine's volume is reduced greatly under the prerequisite that satisfies the projection demand.

Optionally, the first light, the second light and the third light respectively belong to one of R, G, B three-color light, and all the three are different.

By adopting the technical scheme, white light can still be output under the condition that the three light sources are all small-volume monochromatic light sources, and the volume of the light source assembly is reduced.

Optionally, the first light, the second light and the third light source have the same spectrum.

By adopting the technical scheme, under the condition that the power of a single monochromatic light source is limited, the effective display power of the projection engine can be improved by mixing and coaxiality of light rays emitted by the three light sources.

Optionally, the light source assembly further includes a collimating lens, the collimating lens and the light source assembly form a single-channel architecture, and the first light source, the second light source and the third light source form collimated light after passing through the collimating lens.

By adopting the technical scheme, the first light, the second light and the third light are calibrated into the collimated light by the collimating lenses one by one, and the efficiency of reflection on the first dichroic mirror, the second dichroic mirror and the reflecting mirror on the light-emitting light path is improved.

Optionally, the light mixing component further includes a condenser lens disposed in a light emitting direction of the light mixing component, the condenser lens is a convex lens, and the condenser lens uniformly images coaxial light formed by the light mixing component onto the DLP micro-display panel.

Through adopting above-mentioned technical scheme, first light, second light and third light are by the collimating mirror collimation back, are converged by the condensing lens, form even formation of image illumination facula on DLP micro-display panel for projection engine's lighting system simple structure, compact.

Optionally, the light mixing component includes a lens of a rectangular prism, two opposite sides of the rectangular prism are an incident surface and an exit surface, the remaining two sides are a first reflection position and a second reflection position, the light emitted by the light source component is refracted and incident through the incident surface, then reflected by the first reflection position and the second reflection position in sequence, and finally refracted and emitted through the exit surface;

The first dichroic mirror, the second dichroic mirror and the reflective mirror are all arranged at the first reflective position, and the second reflective position is coated with a reflective coating.

By adopting the technical scheme, the light path is folded back by two degrees, so that the distance between the light source end and the imaging end is shortened under the condition that the total length of the light path is unchanged, the structure is more compact, in addition, the light mixing effect of the light mixing assembly is realized by only occupying the first reflection position, and the rest surfaces of the straight quadrangular prism can carry out additional modulation on the light.

Optionally, at least one of the entrance face and the exit face of the right prism has positive optical power.

By adopting the technical scheme, the collimation degree of light can be improved by the incidence surface with positive focal power, and the emergent surface with positive focal power can enable light spots of the white light beam to be matched with the DLP micro-display panel, so that the display effect is optimized.

Optionally, the two bottom surfaces of the right quadrangular prism are coated with a reflective coating.

By adopting the technical scheme, the light is prevented from leaking from the bottom surface of the right rectangular prism, and the projection light intensity is increased.

Optionally, the second reflection position is a curved surface to realize the function of light condensation.

By adopting the technical scheme, the second reflection position can pre-converge the light, reduce the subsequent modulation pressure, and further shorten the length of the light path, so that the volume of the projection engine is further reduced.

Optionally, air is present between the first dichroic mirror, the second dichroic mirror, and the mirror.

By adopting the technical scheme, the light propagation in the light mixing assembly does not need to depend on a lens, and the dependence of the device on a lens processing technology is reduced.

Optionally, the light emitted by the light source component obliquely irradiates to the DLP micro-display panel (3).

By adopting the technical scheme, as each pixel unit of the DLP micro-display panel has an inclination, light rays can be emitted in a normal direction close to the DLP micro-display panel after being reflected by the DLP micro-display panel.

In summary, the present application includes at least one of the following beneficial technical effects:

1. The three-color light is modulated by the light mixing component, is converged into white light with higher coaxiality, and forms uniform imaging light spots on the surface of the DLP micro-display panel, so that the internal structure of the projection engine is simplified under the condition of meeting the requirement of a projection light source, and the size of projection equipment is miniaturized;

2. The positions of the first dichroic mirror, the second dichroic mirror and the reflective mirror can be set according to requirements, light rays emitted by the light source assembly are firstly modulated by the collecting mirror, so that the light rays are firstly collected at the focus of the collecting mirror, and the size of the light mixing assembly can be further reduced by arranging the light mixing assembly near the focus of the collecting mirror;

3. The first light is reflected at the first dichroic mirror, the second light is transmitted twice by the first dichroic mirror, the third light is transmitted twice by the first dichroic mirror and the second dichroic mirror, and the light intensities of the first light source, the second light source and the third light source are sequentially increased, so that the three light rays have similar light densities when converging to the same optical axis, and the mixed light color unbalance caused by the over-weak third light ray and the over-strong first light ray is avoided.

Drawings

FIG. 1 is a schematic diagram of the light path of a compact DLP projection optical engine according to embodiment 1 of the present application;

FIG. 2 is a schematic diagram of the light path of a compact DLP projection optical engine according to embodiment 2 of the present application;

FIG. 3 is a schematic diagram of the light path of a compact DLP projection optical engine according to embodiment 3 of the present application;

FIG. 4 is a schematic diagram of a compact DLP projection optical engine according to embodiment 4 of the present application;

fig. 5 is a schematic diagram of a compact DLP projection optical engine according to embodiment 4 of the present application.

Reference numerals illustrate:

1. A light source assembly; 11. a first light source; 12. a second light source; 13. a third light source; 14. a condenser; 2. a light mixing assembly; 21. a first dichroic mirror; 22. a second dichroic mirror; 23. a reflective mirror; 24. an incidence surface; 25. an exit surface; 26. a first reflection bit; 27. a second reflection bit; 3. a DLP micro-display panel; 4. a projection assembly; 5. a condensing lens; 6. a projection lens group.

Detailed Description

The application is described in further detail below with reference to fig. 1-5.

The embodiment of the application discloses a compact DLP projection optical engine.

Example 1

Referring to fig. 1, the compact DLP projection optical engine includes a light source assembly 1, a light mixing assembly 2, a DLP micro-display panel 3 and a projection assembly 4, wherein R, G, B three colors of light emitted from the light source assembly 1 are modulated by the light mixing assembly 2 to be mixed to form white light, and then the white light is irradiated to the DLP micro-display panel 3, the DLP micro-display panel 3 is subjected to program control to reflect a light beam with image information, and the light beam is received and projected by the projection assembly 4 to form an image.

The light source assembly 1 comprises a first light source 11, a second light source 12, a third light source 13 and a collecting lens 14, wherein the first light source 11 emits first light, the second light source 12 emits second light, the third light source 13 emits third light, and the first light, the second light and the third light all pass through the collecting lens 14. The first light, the second light and the third light are respectively one of R, G, B three-color light, and the three are different.

Preferably, the first light source 11, the second light source 12 and the third light source 13 are provided with collimating lenses in a one-to-one correspondence manner, the collimating lenses are convex lenses, and the first light source 11, the second light source 12 and the third light source 13 are positioned at the focuses of the corresponding collimating lenses.

In this embodiment, the first light is located in a blue band, the second light is located in a green band, and the third light is located in a red band; the optical axes of the light-emitting light paths of the first light source 11, the second light source 12, and the third light source 13 are coplanar and parallel to each other. The light output intensities of the first light source 11, the second light source 12 and the third light source 13 are sequentially increased.

It should be noted that, although the three-color light mixing is implemented in the present embodiment, in practice, in one embodiment of the present application, the first light source 11, the second light source 12 and the third light source 13 may be configured identically, so that the first light, the second light and the third light have the same spectrum, and a higher light density is implemented, which may enhance the viewing experience on the green AR glasses and other devices.

The optical axis of the condenser 14 is parallel to the optical axes of the first light, the second light and the third light on the side of the condenser 14 away from the light mixing assembly 2, and after passing through the condenser 14, the optical paths of the first light, the second light and the third light deflect and pass through the condenser 14 to be close to the focal point on the side of the light mixing assembly 2.

The light mixing assembly 2 includes a first dichroic mirror 21, a second dichroic mirror 22, and a reflective mirror 23, which are sequentially disposed on the light outgoing path of the light source assembly 1, with the reflective surface of the reflective mirror 23 facing toward one side thereof adjacent to the second dichroic mirror 22. The dichroic mirror has a function of reflecting a part of the wavelength light and passing another part of the wavelength light, and specifically, the reflection band of the first dichroic mirror 21 includes a first light, and the transmission band includes a second light and a third light; the reflection band of second dichroic mirror 22 includes the second light, and the transmission band includes the third light; the reflector reflects light rays of various wavelengths.

The included angles of the first light, the second light and the third light before being reflected by the light mixing component 2 and the first dichroic mirror 21 are sequentially increased, and the reflection angle of the first light and the first dichroic mirror 21, the reflection angle of the second light and the second dichroic mirror 22 and the reflection angle of the third light and the reflective mirror 23 are sequentially reduced.

It should be noted that the above arrangement is only a preferred embodiment of the present example in view of shortening the optical path and miniaturizing the structure. In practice, under the premise of ensuring that the first dichroic mirror 21, the second dichroic mirror 22, and the reflective mirror 23 are sequentially arranged in the light-emitting direction of the light source assembly 1, there is a case where the angle between the third light ray and the first dichroic mirror 21 is smaller than the angle between the second light ray and the first dichroic mirror 21.

The first light, the second light and the third light are modulated by the light mixing component 2 and then coaxial, and are mixed into light beams of white light.

The DLP micro-display panel 3 is disposed on the light path of the white light and is disposed at an angle with respect to the white light, and specifically, the angle between the white light and the normal line of the DLP micro-display panel 3 is 24 ° or 34 °. The DLP micro-display panel 3 is program controlled to reflect the received white light beam into an output light beam having image information. Optionally, in order to adapt the light path to the structure of the projection device, other optical elements may be further arranged between the light mixing assembly 2 and the DLP micro-display panel 3 to change the light path direction.

The projection assembly 4 is disposed on the optical path of the output beam, and is used for modulating and projecting the output beam onto a wall, curtain or other display medium to form an image. In this embodiment, the projection assembly 4 includes a readout prism, where the readout prism is a prism and the cross section of the readout prism is an isosceles right triangle, and a side corresponding to a hypotenuse of the isosceles right triangle is a reflecting surface. The output beam is incident perpendicular to one of the right-angle sides, reflected by the reflecting surface, and then exits from the other right-angle side.

Specifically, the light beam may not pass through the readout prism when entering the DLP micro-display panel 3, but may also pass through the readout prism, in which case the inclined side surface of the readout prism is not completely covered by the reflective material, and only the part receiving the output light beam is coated with the reflective coating, which is a conventional means in the industry, and will not be repeated here.

The implementation principle of the embodiment 1 is as follows:

The first light source 11, the second light source 12 and the third light source 13 work simultaneously, emit first light, second light and third light which are parallel to each other, and after the three light beams irradiate the surface of the condenser 14, the light path deflects and passes through the condenser 14 to be close to the focal point on one side of the light mixing component 2.

The first light is reflected by the first dichroic mirror 21.

The second light is transmitted by the first dichroic mirror 21 and then reflected by the second dichroic mirror 22, and the reflected second light is transmitted by the first dichroic mirror 21 coaxially with the first light.

The third light is sequentially transmitted by the first dichroic mirror 21 and the second dichroic mirror 22, and then reflected by the reflecting mirror 23, and the reflected third light is sequentially transmitted by the second dichroic mirror 22 and the first dichroic mirror 21, coaxially with the first light.

The first light, the second light and the third light which are coaxial are mixed into white light and are irradiated to the surface of the DLP micro-display panel 3 to form uniform imaging illumination spots, and the DLP micro-display panel 3 reflects the white light into an output light beam with image information and propagates to the projection component 4.

Since only the light mixing component 2 is disposed between the light source component 1 and the DLP micro-display panel 3, the light mixing component 2 itself achieves the effect of uniformly irradiating the light source light rays with uniform light emission to the DLP micro-display panel 3, so in this embodiment, no light homogenizing structure such as compound eye structure is required, and the whole projection engine is miniaturized.

It should be noted that, in the present embodiment, the coaxial white light formed by mixing the first light, the second light and the third light forms a uniform imaging illumination spot on the surface of the DLP micro-display panel 3, which depends on the uniformity of the light emitted from the light source assembly 1 itself, and if the cost is limited, the accuracy of the first light source 11, the second light source 12 or the third light source 13 is not sufficient, and may be imaged near the DLP micro-display panel 3. This is a common disadvantage in the art, and is a normal phenomenon for low cost DLP projection engines, and does not affect the path direction.

The output light beam enters the vertical incidence reading prism through one right-angle side surface of the reading prism, is reflected by the inclined side surface, and then is emitted perpendicular to the other right-angle side surface of the reading prism. The outgoing light beam falls on the projection medium to form an image.

In addition, the light with longer wavelength has smaller energy loss when penetrating the dichroic mirror, so the wavelengths of the three light rays emitted by the light source assembly 1 are increased along with the increase of the number of the penetrating optical elements, the energy loss in the transmission process is reduced, and the heating condition of the light mixing assembly 2 is relieved. The same applies to the sequential increasing of the light intensities of the first light source 11, the second light source 12 and the third light source 13, and the fine adjustment of the light source side enables the balance of various components in the white light beam output by the light mixing component 2 as much as possible, so as to avoid the color distortion of projection.

Example 2

Referring to fig. 2, this embodiment is different from embodiment 1 in that:

The light mixing assembly 2 of this embodiment includes a prismatic lens, two bottom surfaces of the prismatic lens are coated with a reflective coating, two opposite side surfaces of the prismatic lens are respectively an incident surface 24 and an exit surface 25, and the remaining two side surfaces are respectively a first reflection position 26 and a second reflection position 27. The light emitted from the light source assembly 1 enters through the incident surface 24, is reflected at the first reflection position 26 and the second reflection position 27 in sequence, and finally exits from the exit surface 25.

The first dichroic mirror 21, the second dichroic mirror 22, and the reflective mirror 23 are disposed at the first reflection position 26, specifically, may be attached to the outside of the rectangular prism, or may be embedded in the inside of the rectangular prism through a process such as coating. The second reflective sites 27 are coated with a reflective coating. Preferably, at least one of the exit face 25 and the entrance face 24 has positive optical power.

The implementation principle of the embodiment 2 is as follows:

The light mixing assembly 2 has a more compact structure, and the first dichroic mirror 21 and the second dichroic mirror 22 only occupy the first reflection position, so that the remaining sides of the rectangular prism can modulate light paths. Specifically, the entrance face 24 of positive power may collimate light; the outgoing surface 25 with positive focal power can make the white light beam more convergent and match the size of the DLP micro-display panel 3; the second reflective locations 27 may also be convex or concave to achieve a concentrating or diverging effect.

It should be noted that, in this embodiment, each optical lens is integrated in the right quadrangular prism, and only for the purpose of simplifying the structure and reducing the volume, the straight line distance between the light source end and the imaging end of the optical path is compressed by at least two foldback of the optical path under the condition that the total length of the optical path is unchanged. Therefore, between the different lenses, whether inside the quadrangular prism lens of the present embodiment or in the air of embodiment 1, the propagation path of the light rays in the uniform medium is a straight line, and the uniform medium itself does not exert an effect of modulating the light rays.

Example 3

Referring to fig. 3, this embodiment is different from embodiment 1 in that:

The first dichroic mirror 21, the second dichroic mirror 22, and the reflecting mirror 23 in the present embodiment are parallel to each other, and the first light, the second light, and the third light are parallel to each other when irradiated to the first dichroic mirror 21.

The implementation principle of the embodiment 3 is as follows:

The first, second, and third light rays parallel to each other are modulated by the first, second, and reflective mirrors 21, 22, and 23 parallel to each other and then coaxially mixed into a white light beam.

Example 4

Referring to fig. 4 and 5, this embodiment is different from embodiment 1 in that:

The light mixing assembly 2 of the present embodiment further includes a condenser lens 5 of a convex lens and a projection lens group 6. The condensing lens 5 is arranged in the light-emitting direction of the light mixing component 2, and the focus of the condensing lens 5 falls on the DLP micro-display panel 3; the projection lens group 6 is disposed in the light-emitting direction of the entire apparatus.

The implementation principle of the embodiment 4 is as follows:

the condensing lens 14 of embodiment 1 is used for condensing the light emitted from the light source assembly 1, reducing the volume of the light mixing assembly 2, and the condensing lens 5 of embodiment 4 is used for condensing the light mixed by the light mixing assembly 2 onto the DLP micro-display panel 3, reducing the size of the DLP micro-display panel 3.

The above embodiments are not intended to limit the scope of the present application, so: all equivalent changes in structure, shape and principle of the application should be covered in the scope of protection of the application.

Claims (10)

1. A compact DLP projection optical engine comprising

The light source assembly (1), the light source assembly (1) comprises a first light source (11) emitting first light rays, a second light source (12) emitting second light rays and a third light source (13) emitting third light rays, and the first light source (11), the second light source (12) and the third light source (13) are packaged on the same substrate;

the light mixing assembly (2) comprises a first dichroic mirror (21), a second dichroic mirror (22) and a reflecting mirror (23) which are sequentially arranged on a light emitting path of the light source assembly (1), wherein the first dichroic mirror (21) only reflects the first light, the second dichroic mirror (22) only reflects the second light, the third light passes through the first dichroic mirror (21) and the second dichroic mirror (22) and then is reflected by the reflecting mirror (23), and the first light, the second light and the third light are coaxial after being reflected by the light mixing assembly (2);

The DLP micro-display panel (3) is used for receiving light rays and reflecting the light rays modulated by the digital image, and coaxial light rays formed by the first light rays, the second light rays and the third light rays form uniform imaging illumination light spots on the DLP micro-display panel (3); and

The projection component (4) is used for receiving the reflected light rays of the DLP micro-display panel (3) and projecting and emitting the reflected light rays.

2. The compact DLP projection optical engine of claim 1, wherein said first light, said second light and said third light each belong to one of R, G, B three colors of light, and all three are different.

3. The compact DLP projection optical engine of claim 1, wherein the first light ray, the second light ray and the third light source (13) have the same spectrum.

4. The compact DLP projection optical engine of claim 1, wherein the light source assembly (1) further comprises a collimating mirror, the collimating mirror and the light source assembly (1) form a single channel architecture, and the first light source (11), the second light source (12) and the third light source (13) form collimated light after passing through the collimating mirror.

5. The compact DLP projection optical engine of claim 1, wherein the light mixing assembly (2) assembly further comprises a condenser lens (14) disposed in the light exit direction of the light mixing assembly (2), the condenser lens (14) being a convex lens, the condenser lens (14) uniformly imaging the coaxial light formed by the light mixing assembly (2) onto the DLP microdisplay panel (3).

6. The compact DLP projection optical engine as claimed in claim 1, wherein the light mixing assembly (2) comprises a lens of a right prism, two opposite sides of the right prism are an incident surface (24) and an exit surface (25), respectively, the remaining two sides are a first reflection site (26) and a second reflection site (27), and light rays emitted from the light source assembly (1) are refracted and incident through the incident surface (24), then reflected by the first reflection site (26) and the second reflection site (27) in sequence, and finally refracted and emitted through the exit surface (25);

The first dichroic mirror (21), the second dichroic mirror (22) and the reflective mirror (23) are all arranged in the first reflective position (26), and the second reflective position (27) is coated with a reflective coating.

7. The compact DLP projection optical engine of claim 6 wherein at least one of the entrance face (24) and exit face (25) of the right prism has positive optical power; and/or

The two bottom surfaces of the right quadrangular prism are coated with reflective coatings.

8. The compact DLP projection optical engine of claim 6 wherein said second reflective location (27) is curved to achieve a light focusing function.

9. The compact DLP projection optical engine of claim 1 wherein air is present between the first dichroic mirror (21), the second dichroic mirror (22) and the mirror.

10. The compact DLP projection optical engine as claimed in any one of claims 1-9, characterized in that the light rays emitted by the light source assembly (1) impinge obliquely on the DLP micro-display panel (3).