CN218957007U - Micro-display light engine and projector - Google Patents

Abstract

The utility model discloses a micro display light engine, which comprises a micro-LED panel, cooling liquid, a thin lens, a metal frame, a connecting column and a projection lens; the micro-LED panel comprises a substrate, a plurality of micro-LED grains with luminous pixels, a glass plate, a metal bracket, a sealing frame, a radiator, filling glue and transparent heat-conducting glue. The utility model also discloses a single-engine, double-engine and three-engine full-color projector. The utility model has the remarkable characteristics of relatively simple manufacture, capability of realizing preliminary productization, excellent heat dissipation, good heat stability, higher contrast, color gamut and the like, and lays a certain foundation for carrying out actual productization on the novel micro-LED micro-display projection technology.

Description

Micro-display light engine and projector

Technical Field

The utility model relates to the technical field of projection, in particular to a micro display light engine and a projector for carrying out optical amplification display on a micro display device.

Background

The new generation of display technology is most expected to have dual functions of illumination or pixel luminescence, and in some specific products, such as LCD televisions, mini/micro-LEDs are used as backlight, and in wear fields of VR (virtual reality), AR (augmented reality), MR (mixed reality) and the like, strong and more omnibearing technical superiority is gradually revealed by using micro-LEDs as pixel luminescence devices. In practical applications of the projection display industry, many patent technology prototypes and imaginative technical exploration, such as chinese patent publication No. CN110687742A, CN113242415A, CN110687741A, CN216718895U, CN109976079a, etc., have also emerged in succession, and although many patents are also considered to be lacking or withdrawn in inventive innovation, the description of micro-LED technology has attracted widespread social attention.

For the micro-LED display panel at the present stage, the micro-LED display panel is applied to the traditional projection industry to realize full-color display, more than 1000 lumens and more than 50:1, and a longer production distance. Besides factors such as substrate stripping, bonding, mass transfer (Masstransfer), high-power active driving and the like of Micro-LED self manufacturing technology, the Micro-LED self manufacturing technology is also characterized by scarcity of a panel with higher power (because the projection needs as high brightness as possible), and a series of problems such as effective treatment, panel light color consistency and the like of the panel with higher power are also difficult, but the research and development enthusiasm of people and the expectation of a new generation of Micro-display technology are not influenced.

The micro-LED projection display technology of the existing embryonic form still has no more reasonable opinion and uniform effort in research and development directions, including but not limited to specific technical modes of adopting a color light panel, adopting three color-based panels and carrying out RGB light combination, and whether a microlens matrix corresponding to each other is manufactured in front of a light emitting pixel, which is essentially because of the lack of a feasible implementation method. This is not only a manufacturing difficulty faced by the micro-LED panel industry at the present stage, but also a problem of communication obstacle between upstream and downstream of a supply chain caused by technical requirements of reverse pushing the micro-LED panel according to the performance definition of the projector, and a practical problem faced by the projection industry such as price/performance choice of the projector, optics of the projector, heat dissipation design and the like, and these extensive and practical problems all make the technical challenges of implementing the commercialization to develop the micro-LED projection product very great. And people often only realize a specific technical attack, and the method has positive help and obvious significance for mass production and landing of future micro-LED projection products.

As disclosed in the well-known analytical institute in the industry, IHS mark, entitled "IHS mark Micro-LED display technology and market report", it is predicted that Micro-LED panel production and marketing will mature and blow out in 2024, i.e. represent a huge release of the technology towards maturation, significant cost reduction and productivity, so that development of a Micro-LED projection product of practical value has been not yet made my.

Disclosure of Invention

The utility model aims to promote and solve some specific technical problems which are required to be faced by the production of micro-LED projection display, so that the micro-LED projection display can be further developed in the direction of the production of the floor type. The utility model provides a novel micro-display light engine based on micro-LED pixel luminescence and projection amplification, which has the remarkable characteristics of relatively simple manufacture, capability of realizing preliminary productization, excellent heat dissipation, good heat stability, higher contrast, higher color gamut and the like, and lays a certain foundation for the actual productization of the novel micro-LED micro-display projection technology.

In order to achieve the above object, the present utility model provides a micro display light engine comprising a micro-LED panel, a cooling liquid, a thin lens, a metal frame, a connection post, and a projection lens.

The micro-LED panel comprises a substrate, a plurality of micro-LED grains with luminous pixels, a glass plate, a metal bracket, a sealing frame, a radiator, filling glue and transparent heat-conducting glue.

The sealing frame is square-tube-shaped, and the length and width dimensions of the section of the sealing frame are equal to those of the glass plate; the substrate, the sealing frame and the incident surface of the glass plate are sequentially attached; the micro-LED packaging structure comprises a substrate, a sealing frame, a glass plate, a driving circuit and a sealing plate, wherein the substrate is arranged between the substrate, the sealing frame and the glass plate, and a plurality of micro-LED crystal grains and the driving circuit are arranged on the substrate and used for addressing the micro-LED crystal grains one by one; electrodes of the micro-LED crystal grains are bonded with the driving circuit arranged on the substrate; the electrodes of the micro-LED crystal grains are of a flip-chip structure.

The length of the sealing frame is 6-10 mu m larger than the height value of the top surfaces of the micro-LED crystal grains higher than the surface of the substrate.

The luminous colors of the micro-LED crystal grains are single primary colors, double primary colors or three primary colors.

The metal frame is tubular, one end of the metal frame is attached to the emergent surface of the glass plate, and the other end of the metal frame is connected with the thin lens to form a closed cavity; the closed cavity is filled with the cooling liquid; the glass plate, the cooling liquid and the thin lens constitute one liquid lens.

The metal bracket covers one end of the substrate, the sealing frame, the glass plate and the metal frame, and the substrate is attached to the inner surface of the metal bracket; the filling glue is filled among the metal frame, the glass plate and the metal bracket; the radiator is mounted on the back of the metal bracket in a fitting mode.

And the emergent surface of the glass plate is manufactured into a first black matrix in a region except for the light emergent angle theta selected by the micro-LED crystal grains.

And the incidence surface of the glass plate is manufactured into a second black matrix in the area except the light emergent angle theta selected by the micro-LED crystal grains.

The transparent heat-conducting glue is manufactured on the incidence surface of the glass plate in the area opposite to the micro-LED crystal grains, and the top surfaces of the micro-LED crystal grains, the transparent heat-conducting glue and the incidence surface of the glass plate are sequentially attached; the thickness of the transparent heat-conducting glue is 10 mu m.

The projection lens comprises a lens outer barrel, and an incident lens group, a middle lens group and an emergent lens group which are arranged in the lens outer barrel and are sequentially arranged according to the light travelling direction; the incident lens group, the intermediate lens group and the emergent lens group all comprise at least one lens; the metal bracket is connected with the lens outer cylinder through the connecting column; the number of the connecting posts is at least three.

And Fno after the liquid lens and the projection lens are combined is less than or equal to 1.2.

Preferably, the glass plate is made of optical crystals.

Optionally, the incident lens group includes a first lens and a second lens sequentially arranged in a light traveling direction; the number of the lenses of the middle lens group is one; the emergent lens group comprises a fourth lens and a fifth lens which are sequentially arranged according to the light travelling direction.

Preferably, the thin lens is concave-convex, and the convex surface is opposite to the glass plate; the convex surface and the concave surface of the thin lens are one or a combination of any two of free curved surfaces, aspheric surfaces and spherical surfaces.

The thickness of the thin lens is equal or unequal from the center to the edge.

The surface shape of the light passing surface of the concave surface of the thin lens is as follows: when the angles of the light rays emitted by the micro-LED crystal grains are larger than the limitation of the FNO value on the angles of the light rays, the light rays larger than the limitation angle of the FNO value are totally reflected at the concave surface.

Optionally, the absolute value of the difference between the refractive indices of the cooling liquid and the thin lens is equal to or less than 0.2; the absolute value of the difference between the refractive indexes of the cooling liquid and the glass plate is less than or equal to 0.3.

Optionally, the filler is silicone rubber.

Optionally, the transparent heat-conducting glue is optical grade silica gel.

A single-engine full-color projector comprises a micro-display light engine, wherein the number of the micro-display light engines is one, and the luminous color of a plurality of micro-LED crystal grains included in the micro-display light engine is three primary colors.

The double-engine full-color projector comprises two micro-display light engines, wherein when the luminous color of a plurality of micro-LED crystal grains included in a first micro-display light engine is a single primary color, the luminous color of a plurality of micro-LED crystal grains included in a second micro-display light engine is a double primary color, and the two primary colors of the second micro-display light engine do not contain the luminous color of the first micro-display light engine; the two micro-display light engines are arranged at an angle a or are arranged in parallel, wherein the angle a is less than or equal to 14 degrees.

When the two micro-display light engines are arranged in parallel, the two micro-display light engines are arranged in an off-axis manner; the first micro-display light engine is offset by d towards the second micro-display light engine, and the second micro-display light engine is offset by e towards the first micro-display light engine; let the optical axis of the first micro-LED panel included in the first micro-display light engine be L51, the optical axis of the second micro-LED panel included in the second micro-display light engine be L55, the distance between the optical axis L51 and the optical axis L55 be c, and the projection magnification of the two micro-display light engines be β, then c=β (d+e).

A three-engine full-color projector comprises three micro-display light engines, wherein each micro-display light engine comprises a plurality of micro-LED crystal grains with one of three primary colors.

The first micro-display light engine and the middle micro-display light engine are arranged at an angle b/2, and the third micro-display light engine and the middle micro-display light engine are arranged at an angle b/2, wherein the angle b is less than or equal to 28 degrees.

Or three micro display light engines are arranged in parallel, and two micro display light engines on two sides are distributed: the first micro-display optical engine is offset by g towards the middle micro-display optical engine, and the third micro-display optical engine is offset by k towards the middle micro-display optical engine; let the optical axis of the first micro-LED panel included in the first micro-display light engine be L61, the optical axis of the second micro-LED panel included in the middle micro-display light engine be L62, the distance between the optical axis L61 and the optical axis L62 be f, and the projection magnification of the two micro-display light engines be β, then f=βg; let the optical axis of the third micro-LED panel included in the third micro-display light engine be L63, the distance between the optical axis L63 and the optical axis L62 be j, and the projection magnification of the two micro-display light engines be β, j=βk.

The beneficial effects of the utility model are as follows:

1. the utility model aims at manufacturing a small FNO lens (FNO is less than or equal to 1.2), and effectively dissipates heat of micro-LED crystal grains and forms a liquid lens through cooling liquid, transparent heat-conducting glue, glass plate and the like, and the liquid lens can obviously reduce the influence of stray light on the contrast of a projection image caused by too small FNO of the projection lens. Meanwhile, the black matrix is manufactured on the incident surface and the emergent surface of the glass plate, so that the micro-display optical engine is ensured to have higher contrast as much as possible, and stray light is reduced. These innovative approaches have made micro-LED microdisplay projection technology a solid step forward. The utility model has the remarkable characteristics of relatively simple manufacture, capability of realizing preliminary (namely, under the current practical conditions of low resolution, and the like) productization, excellent heat dissipation, good heat stability, and the like.

2. The single-engine full-color projector has the advantages of being very simple in structure, capable of realizing preliminary productization, and capable of experiencing the remarkable advantages of high color gamut, high contrast, high efficiency and the like brought by an advanced micro-LED micro-display technology.

3. The double-engine and three-engine full-color projector has the characteristics of simple structure, can improve the brightness of the micro-LED applied to projection products under the current technical conditions, and remarkably reduces the manufacturing difficulty of the micro-LED panel.

Drawings

In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, it being obvious that the drawings in the following description are only some embodiments of the utility model, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a schematic diagram of an embodiment of the present utility model;

FIG. 2 is a schematic view showing the arrangement of a black matrix of a glass plate according to the present utility model;

FIG. 3 is an enlarged partial schematic view of the present utility model;

FIG. 4 is a schematic view of two microdisplay light engines at an angle a;

FIG. 5 is a schematic diagram of two microdisplay light engines in a side-by-side arrangement according to the present utility model;

FIG. 6 is a schematic view of three microdisplay light engines of the present utility model disposed at an angle b;

FIG. 7 is a schematic diagram of three microdisplay light engines in a side-by-side arrangement according to the present utility model;

FIG. 8 is a schematic view of a micro-LED die and microlens;

FIG. 9 is a schematic diagram of the prior art;

fig. 10 is a schematic diagram of the prior art.

Detailed Description

In order that those skilled in the art may better understand the technical solutions of the present utility model, the following detailed description of the present utility model with reference to the accompanying drawings is provided for exemplary and explanatory purposes only and should not be construed as limiting the scope of the present utility model.

It should be noted that: like reference numerals and letters denote like items in the following figures, and thus once an item is defined in one figure, no further definition or explanation thereof is necessary in the following figures.

It should be noted that, the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," "outer," and the like refer to an azimuth or a positional relationship based on that shown in the drawings, or that the inventive product is commonly put in place when used, merely for convenience in describing the present utility model and simplifying the description, and do not indicate or imply that the apparatus or elements referred to must have a specific azimuth, be configured and operated in a specific azimuth, and thus should not be construed as limiting the present utility model. Furthermore, the terms "first," "second," "third," and the like are used merely to distinguish between descriptions and should not be construed as indicating or implying relative importance.

Furthermore, the terms "horizontal," "vertical," "overhang," and the like do not denote a requirement that the component be absolutely horizontal or overhang, but rather may be slightly inclined. As "horizontal" merely means that its direction is more horizontal than "vertical", and does not mean that the structure must be perfectly horizontal, but may be slightly inclined.

In the description of the present utility model, it should also be noted that, unless explicitly specified and limited otherwise, the terms "disposed," "mounted," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present utility model will be understood in specific cases by those of ordinary skill in the art.

Although the full-color micro-LED has a certain technical problem, firstly, the method is limited by the process and technology of material growth, namely, high-efficiency R (red), G (green) and B (blue) micro-LED grains [ "wafer particles", "chip particles", "luminescent (sub-) pixels", and the like are difficult to grow on the same substrate material, so that the proposal of RGB full-color display is realized by transferring a large amount of R, G, B micro-LED grains to the same structural substrate (the substrate is silicon-based or glass-based at the present stage) or adopting short-wave (such as ultraviolet or blue light) micro-LED grains to excite fluorescent powder or quantum dot material of long wave. The schemes have achieved a certain implementation result and in the continuous development and maturity, the wearable products such as micro-LED child watches with luminous pixels realize preliminary mass production, lay a preliminary foundation for micro-LED projection productization and also create conditions for the actual successful implementation of the utility model.

Each micro-LED crystal grain is characterized by emitting light (or lambertian) in the form of a cosine function, so that the projection lens needs a very large numerical aperture, namely a very small Fno (aperture) value, to efficiently utilize and project light. However, the lens projection picture with large numerical aperture is necessarily low in contrast, so how to ensure that the projection picture has higher contrast is a basic condition of whether the product has practicability.

The lens (micro lens array) and other modes are utilized by people to improve the light emitting (or light extracting) efficiency of the direct-view micro-LED crystal grain, and certain effect is achieved. Therefore, it is considered that the light emitting angle of the micro-LED die is reduced by using a lens or the like, so as to reduce the difficulty of designing and manufacturing the projection lens, or the projection lens is easier (or cheaper) to implement in theory, and some rudiment patent technologies are generated, such as CN109716174A, CN114846364A, CN112802403A, CN112802404a and the like, all attempt to change the light emitting angle of the micro-LED die, i.e. shape the light emitting of the micro-LED die according to a required index. Referring to fig. 8-9, micro-LED dies 11 'with light emitted by a plurality of pixels are fabricated on a substrate 1', each micro-LED die 11 'corresponds to one light-gathering microlens 2', and accordingly, a plurality of microlenses 2 'form a microlens array, so that the Fno value of the projection lens 3' can be significantly increased theoretically. As shown in fig. 8, any three light rays L1', L2' and L3' are emitted from the micro-LED die 11', and the light rays L1' -L3' are refracted and changed in angle when they enter and exit the micro-lens 2' (i.e., so-called light ray shaping in the industry).

Furthermore, the optical system of the R, G, B three-piece micro-LED luminous pixel panel is also processed in a method. Referring to fig. 10, a plurality of red micro-LED dies 211 'are fabricated on an R substrate 21', each die 211 'corresponding to one microlens 22'; a plurality of green micro-LED dies 231 'are fabricated on the G substrate 23', each die 231 'corresponding to one microlens 24'; a plurality of blue micro-LED dies 251 'are fabricated on the B substrate 25', one microlens 26 'for each die 251'. The light is combined by the X prism 27 'and projected by the projection lens 28'. The technique shown in fig. 10 is also not merely to increase the Fno value of the projection lens 28', but is primarily to accommodate the very demanding aperture definition of the X-prism 27' (or other dichroic optical film technology-based light combining device).

It is apparent that the above technique is not practical to significantly compress the light exit angle of a lambertian emitting micro-LED die such as die 11 'by a single lens such as microlens 2', for example, from a single side 90 ° (Fno about 0.5) to a single side 12 ° (Fno about 2.4), as shown in fig. 9. Meanwhile, the microlens array formed by a plurality of microlenses needs to be realized in one-to-one correspondence (optical coaxiality) with the optical centers of a plurality of micro-LED crystal grains, and the fine idea is uncertain, and particularly, the fine idea is almost impossible to realize after the massive transfer and the die re-solidification. And the single lens compresses and shapes the emergent angle of the micro-LED crystal grain, and the compression and shaping effect depends on the ratio of the light-transmitting area of the single lens to the top light-emitting area of the micro-LED crystal grain, which is constrained by a plurality of engineering conditions such as the size of the micro-LED crystal grain, the spacing of the crystal grain and the like. If the ratio of the light-passing area of the single lens to the top light-emitting area of the micro-LED die is close to 1, the single lens cannot change the light-emitting angle of the micro-LED die (unless the efficiency of extracting light is greatly sacrificed), i.e., the compression shaping effect approaches zero. While the final development effort is conceivable if the development is to be blindly done for these uncertain goals.

Compared with various conventional possibly uncertain prototype patent technologies, the utility model takes the manufacture of a small FNO lens (FNO is less than or equal to 1.2) as an initial aim, and the cooling liquid 21, the transparent heat-conducting glue 17, the glass plate 12 and the like are used for completing the heat dissipation of the micro-LED crystal grain 11 and forming a liquid lens, and ensuring that the contrast of a projection image is influenced by stray light due to the fact that the FNO of the projection lens is too small is properly solved, so that the micro-LED micro-display projection technology takes a solid step forward.

Embodiment one:

as shown in fig. 1 to 3, the micro display light engine provided in this embodiment includes a micro-LED panel, a cooling liquid 21, a thin lens 22, a metal frame 23, a connection post 24, and a projection lens.

The micro-LED panel comprises a substrate 1, a plurality of micro-LED crystal grains 11 with luminous pixels, a glass plate 12, a metal bracket 13, a sealing frame 14, a radiator 15, filling glue 16 and transparent heat-conducting glue 17. With the current technology, the color consistency (tolerance range of wavelength of each primary color < 2 nm) cannot be too demanding, but the brightness consistency is corrected with a certain solution.

The sealing frame 14 is square, and the length and width dimensions of the cross section of the sealing frame 14 are equal to those of the glass plate 12. The sealing frame 14 is preferably (but not limited to) made of the same material as the glass plate 12. Preferably, but not limited to, the substrate 1, glass plate 12 and sealing frame 14 are all made of sapphire glass to achieve excellent thermal conductivity and to eliminate the risk of failure due to thermal expansion and contraction. The incident surfaces of the substrate 1, the sealing frame 14 and the glass plate 12 are sequentially attached; the micro-LED chips 11 and the driving circuits for addressing the micro-LED chips 11 are arranged on the substrate 1 (the low-temperature polysilicon TFT active driving circuits are manufactured on the substrate 1, and the technologies such as Beijing east and Star photoelectric and the enterprises such as friendly photoelectric and samsung are very mature in the country and are not drawn in the figure and are not repeated); the electrodes of the micro-LED dies 11 are bonded to the driving circuit disposed on the substrate 1, and the electrodes of the micro-LED dies 11 are in a flip-chip structure (not shown).

The length of the sealing frame 14 (the length of the square tube) is 6 μm to 10 μm larger than the height value of the top surface of the micro-LED die 11 above the surface of the substrate 1. After the micro-LED die 11 is transferred to the receiving substrate (substrate 1) in a huge amount and bonded, the top of the micro-LED die 11 is uneven, on one hand, the thickness of the micro-LED die 11 has a certain tolerance range, on the other hand, the height difference can be generated during bonding, so that the length dimension selection of the sealing frame 14 is very important, otherwise, the heat dissipation effect of the glass plate 12 and the transparent heat-conducting glue 17 on a plurality of micro-LED dies 11 is obviously reduced.

The luminous colors of the micro-LED crystal grains are single primary colors, double primary colors or three primary colors. The micro-LED panel is sequentially single-base color, double-base color and three-base color from low to high in manufacturing difficulty. The three primary colors, i.e. full color display, are realized by manufacturing the micro-LED die 11 of R, G, B on the same substrate 1 as described above, or by exciting long-wave fluorescent powder or quantum dot material with the micro-LED die 11 of short wave (such as ultraviolet or blue light). Under the current technical conditions, the wavelength excitation technology has more difficult problems.

The metal frame 23 is tubular, one end of the metal frame 23 is attached to the exit surface of the glass plate 12, and the other end is connected to the thin lens 22 to form a closed cavity; the closed cavity is filled with the cooling liquid 21; the glass plate 12, the cooling liquid 21 and the thin lens 22 constitute one liquid lens. Preferably, the inner wall of the metal frame 23 is made black to facilitate absorbing stray light, and the outer wall may be optionally made with a necessary heat spreading structure to dissipate heat from the cooling liquid 21.

The metal bracket 13 covers one end of the substrate 1, the sealing frame 14, the glass plate 12 and the metal frame 23, and the substrate 1 is attached to the inner surface of the metal bracket 13; the filling glue 16 is filled among the metal frame 23, the glass plate 12 and the metal bracket 13, and plays a role in further strengthening and differentiating stress of the materials such as the metal frame 23, the substrate 1 and the glass plate 12, namely, the stress of the micro-LED panel is concentrated on the metal bracket 13 as far as possible; the heat sink 15 is attached to the back surface of the metal bracket 13. The heat sink 15 is preferably, but not limited to, a straight rib profile heat sink.

Referring to fig. 2 and 3, the exit surface of the glass plate 12 is formed into a first black matrix 121 in a region (a region other than the light rays L1 and L2 in fig. 3) except for the light exit angle θ selected by the micro-LED dies 11; the light emitting angle θ is a specific value, and the angle corresponding to the Fno is taken as a reference design value, but the value of the light emitting angle θ is not meant to be equal to the limit value of Fno [ arcsin (0.5/Fno) ]. Light rays with the micro-LED die 11 light emitting angle > the Fno corresponding angle [ arcsin (0.5/Fno) ] cannot be utilized by the light engine, so that the light rays are shielded as much as possible to reduce stray light. When the fno=1.2, light of about > 24.6 ° is already unavailable. However, the micro-LED die 11 is not an absolute point light source, so the specific value of θ is often an empirical embodiment in design, and the micro-LED die 11 emits light with an angle > θ, which is blocked by the first black matrix 121 as much as possible, so as to ensure the contrast of the projected image. The specific size of the first black matrix 121 is mainly related to the size of the micro-LED die 11, the thickness of the transparent heat conductive paste 17, the choice of θ, and the thickness of the glass plate 12.

The manufacturing process of the first Black Matrix 121 is very mature, similar to the manufacturing process of BM (Black Matrix, i.e. Black Matrix, black frame, etc.) of LCD, and the level of BM technology is more than sufficient for the manufacturing of the first Black Matrix 121 according to the present utility model, because the line width of BM is already very mature and stable under the current technical conditions (3 μm or less), while micro-LED panel for projection does not need such a fine (3 μm or less) structure at present. Meanwhile, considering that the first black matrix 121 (organic material+toner) and the cooling liquid 21 do not affect each other, the formation of a transparent protective film on the surface of the first black matrix 121 is a common sense problem, and will not be described again.

Accordingly, the incident surface of the glass plate 12 is formed into a second black matrix 122 in a region other than the light-emitting angle θ selected by the micro-LED dies 11. The specific size of the second black matrix 122 is mainly related to the size of the micro-LED die 11, the value of θ, and the thickness of the transparent heat conductive paste 17.

The arrangement of the first black matrix 121 and the second black matrix 122 also helps to further enhance the depth of field of the projection lens.

The transparent heat-conducting glue 17 is manufactured on the incidence surface of the glass plate 12 in the area opposite to the micro-LED crystal grains 11, and the top surfaces of the micro-LED crystal grains 11, the transparent heat-conducting glue 17 and the incidence surface of the glass plate 12 are sequentially attached; the thickness of the transparent heat-conducting glue 17 is 10 mu m; preferably, the transparent heat-conducting gel 17 is optical grade silica gel, so as to obtain better heat conductivity, enough light resistance and excellent interface filling elasticity, and the transmittance is better. The manufacturing process of the transparent heat-conducting glue 17 is similar to the manufacturing method of the first black matrix 121 and the second black matrix 122.

The projection lens comprises a lens outer cylinder 34, and an incident lens group 31, a middle lens group 32 and an emergent lens group 33 which are arranged in the lens outer cylinder 34 and are sequentially arranged according to the light travelling direction; the incident lens group 31, the intermediate lens group 32, and the exit lens group 33 each include at least one lens; the metal bracket 13 is connected with the lens outer cylinder 34 through the connecting column 24; the number of the connecting posts 24 is at least three.

And Fno after the liquid lens and the projection lens are combined is less than or equal to 1.2.

In this embodiment, the micro-LED panel is a 2.6 inch panel (modified from the full-color micro-LED panel process of the latest smart watch) as the pixel light source of the present utility model, the resolution is 480×rgb×272, each (group of) light-emitting pixels includes R, G, B directly-emitting sub-pixel grains, and the three sub-pixels are arranged in a "delta" shape; the size of each light emitting subpixel is about 12 μm by 12 μm; to ensure a smooth fabrication of the substrate 1, the center-to-center distance of each group of light emitting pixels is 0.12mm. In the projection lens of the embodiment, the spatial frequency MTF value of the projection lens is 5Lp/mm, the total design target value can be easily more than 65%, and when fno=1.2, the depth of field, aberration, distortion and other indexes are excellent; the number of the incident lens group 31 of the projection lens is two, and the incident lens group 31 is provided with a first lens 311 (positive lens) and a second lens 312 (negative lens) in sequence according to the light travelling direction, and the incident lens group 31 bears main chromatic aberration correction; the number of lenses of the intermediate lens group 32 is one, contributing to the main magnification; the number of lenses of the exit lens group 33 is two, and the fourth lens 331 (negative lens) and the fifth lens 332 (positive lens) are in this order in the light traveling direction. The substrate 1 is formed by a series of processes such as film deposition, photoresist coating, exposure, development, etching, photoresist stripping, etc. on a sapphire glass, and then forms a driving circuit of the micro-LED die 11 and an electrode bonded with the micro-LED die 11, and of course, further includes a contact Pad (Pad) of other peripheral circuits, and a large-current inflow and outflow wiring structure, etc. which will not be described again.

The thin lens 22 is preferably, but not limited to, concave-convex, with the convex surface opposite the glass plate 12; the convex and concave surfaces of the thin lens 22 are one or a combination of any two of free-form surfaces, aspherical surfaces, or spherical surfaces. In this embodiment, the convex and concave surfaces of the thin lens 22 are free curved surfaces, and the thickness varies from the center to the edge, but the offset value is relatively very small, and is substantially nearly equal to the thickness to ensure the best precision in injection molding.

The surface shape of the light passing surface of the concave surface of the thin lens 22 is: when the angle of the light rays emitted by the micro-LED dies 11 is larger than the limitation of the Fno value on the angle of the light rays, the light rays larger than the limitation angle of the Fno value are totally reflected at the concave surface. It should be specifically noted that, as the micro-LED die 11 is not an absolute point light source, the light emitting angle is larger than the corresponding angle of the Fno value, and in practice, total reflection is not completely achieved, which is also a problem of reasonable selection of the chief ray and the off-axis ray by engineering experience, and will not be repeated.

The absolute value of the difference between the refractive indices of the cooling liquid 21 and the thin lens 22 is 0.2 or less; the absolute value of the difference between the refractive indices of the cooling liquid 21 and the glass plate 12 is 0.3 or less. Proper refractive index matching is selected, fresnel reflection of each interface can be effectively reduced, light transmission efficiency is improved, and stray light is reduced.

Because the micro-LED panel driving circuit is an LTPS TFT technology, a series of process flaws such as screen, mosaic, bright lines, dark lines, uneven bright colors and the like still exist under the technical conditions of the current grain screening, driving circuit and the like after being projected and amplified to 100 inches. The total power consumption of the driving circuit is approximately 100W, each group of pixels is approximately 0.61mW, the R sub-pixels are approximately 0.15mW, the g sub-pixels are approximately 0.24mW, the b sub-pixels are approximately 0.22mW, the remaining about 20W of electric power is consumed by the driving circuit, the micro-display light engine can output luminous flux of more than 800 lumens, the same frame (ANSI, american standard association) that is eight white/eight black contrast ratio is up to 600:1, the color gamut is up to 95% (NTSC), the sequential field contrast ratio (all white/all black) is close to infinity, which is very excellent data, compared with the state LCD or DLP projector, the contrast ratio of projected images, the color gamut, the layering, the second shadow, the character jumping of the display surface, and other high-speed moving pictures are much better, and the temperature rise of each crystal grain, especially the temperature rise of the crystal grain located in the center area of the micro-LED panel, can be controlled in the range of less than 3-4 ℃ and the cooling liquid 21, the heat dissipation condition of the utility model has more excellent heat dissipation performance of more than 2.6 inches under the power of more than 70W. With the progress of technology, brightness and resolution can be improved continuously, and defects of screen, mosaic, bright lines, dark lines, uneven bright colors and the like are overcome.

Example two

The single-engine full-color projector provided by the embodiment includes the micro-display light engine of the first embodiment, wherein the number of the micro-display light engines is one, and the light emitting colors of the micro-LED dies 11 included in the micro-display light engine are three primary colors.

The single-engine projector has the advantages of being very simple in structure, capable of achieving preliminary productization, and capable of experiencing the remarkable advantages of high color gamut, high contrast, high efficiency and the like brought by an advanced micro-LED micro display technology.

Embodiment III:

referring to fig. 4, the dual-engine full-color projector provided in this embodiment includes the micro-display light engines described in the first embodiment, wherein the number of the micro-display light engines is two, when the light emission color of the micro-LED dies 11 included in the first micro-display light engine 341 is a single primary color, the light emission color of the micro-LED dies 11 included in the second micro-display light engine 342 is a dual primary color, and the two primary colors of the second micro-display light engine 342 do not include the color emitted by the first micro-display light engine 341; the two microdisplay light engines 341, 342 are disposed at an angle a. Wherein the angle a is less than or equal to 14 degrees.

As described above, the dual engine mode can improve the output brightness of the projector and reduce the manufacturing difficulty of the micro-LED panel, such as defects of a patterned screen, a mosaic, bright lines, dark lines, uneven bright colors and the like, can be reduced to a certain extent, and has a certain cost performance.

However, instead of the layout shown in fig. 4 to achieve practical projection of the image, it is necessary to perform necessary electronic trapezoidal correction (the driving circuit needs to change the addressing start and stop positions of each row of dies) so that the two micro-display light engines 341 and 342 can both project rectangular images with the same size, and perfect superposition of the output images of the two micro-display light engines 341 and 342 is achieved through necessary mechanical position adjustment, so as to generate a full-color image.

The angle a is based on the actual application scene condition, and depends on the projection ratio of the microdisplay light engines, if the angle a needs to be greater than 14 ° and the two microdisplay light engines 341 and 342 output images to overlap, the depth index of the projection lens is difficult to design and manufacture, so that the angle a has no practical applicability basically.

Embodiment four:

referring to fig. 5, the fourth embodiment differs from the third embodiment in that: the two micro-display light engines 341 and 342 are arranged in parallel (i.e. parallel), and the two micro-display light engines 341 and 342 are arranged in an off-axis manner; the first micro display optical engine 341 is offset by d from the second micro display optical engine 342, and the second micro display optical engine 342 is offset by e from the first micro display optical engine 341; let the optical axis of the first micro-LED panel 131 included in the first micro-display light engine 341 be L51, the optical axis of the second micro-LED panel 132 included in the second micro-display light engine 342 be L55, the distance between the optical axis L51 and the optical axis L55 be c, and the projection magnification of both micro-display light engines 341, 342 be β, c=β (d+e).

The projection lens of the first micro-display light engine 341 is coaxial with the liquid lens (L52), the projection lens of the second micro-display light engine 342 is coaxial with the liquid lens (L56), and a straight line segment (length c) is assumed to be a (straight line segment a is not shown in the figure) between the center (on L51) of the micro-LED panel 131 included in the first micro-display light engine 341 and the center (on L55) of the micro-LED panel 132 included in the second micro-display light engine 342. The off-axis of the projector, i.e., offset, the projection lens and the liquid lens of the first micro-display light engine 341 only need to move integrally along the straight line segment a, or the projection lens and the liquid lens of the second micro-display light engine 342 move integrally along the straight line segment a until the output images of the two micro-display light engines 341, 342 overlap.

In this embodiment, when the two light engines overlap the image, no electronic trapezoidal correction is required, so that the image is not compressed and the best definition can be maintained. Compared with the third embodiment, the installation and debugging are also quite simple, and the usability of the user can be improved.

Fifth embodiment:

referring to fig. 6, the three-engine full-color projector provided in this embodiment includes the micro-display light engine described in the first embodiment, wherein the number of the micro-display light engines is three, and each micro-display light engine includes a plurality of micro-LED dies 11 with light emission colors that are one of three primary colors.

The first micro-display light engine 343 and the middle micro-display light engine 344 are arranged at an angle b/2, and the third micro-display light engine 345 and the middle micro-display light engine 344 are arranged at an angle b/2, wherein the angle b is less than or equal to 28 degrees.

Obviously, the embodiment and the third embodiment have similarity, but the embodiment can output higher brightness, can reduce the manufacturing difficulty of the micro-LED panel and has better cost performance. The defects of the screen, the mosaic, the bright line, the dark line and the like aim at the micro-display light engine with single primary colors, and the method has substantial improvement.

Typically, the three-engine approach is typically, but not limited to, a green microdisplay light engine as the middle stage and red and blue microdisplay light engines on either side of the column.

Example six:

referring to fig. 7, the three-engine full-color projector provided in this embodiment includes the micro-display light engine described in the first embodiment, wherein the number of the micro-display light engines is three, and each micro-display light engine includes a plurality of micro-LED dies 11 with light emission colors that are one of three primary colors.

The three micro display light engines 343, 344, 345 are arranged in parallel, and two micro display light engines 343, 345 on two sides are distributed: the first micro-display light engine 343 is offset by g toward the middle micro-display light engine 344, and the third micro-display light engine 345 is offset by k toward the middle micro-display light engine 344; let the optical axis of the first micro-LED panel 133 included in the first micro-display light engine 343 be L61, the optical axis of the second micro-LED panel 134 included in the intermediate micro-display light engine 344 be L62, the distance between the optical axis L61 and the optical axis L62 be f, and the projection magnification of the two micro-display light engines 343, 344 be β, f=βg; similarly, let the optical axis of the third micro-LED panel 135 included in the third micro-display light engine 345 be L63, the distance between the optical axis L63 and the optical axis L62 be j, and the projection magnification of the two micro-display light engines 345, 344 be β, j=βk.

Obviously, the embodiment and the fourth embodiment have similarity, but the embodiment can output higher brightness, can reduce the manufacturing difficulty of the micro-LED panel, and has better cost performance and practicability.

The foregoing has shown and described the basic principles, principal features and advantages of the utility model. It will be understood by those skilled in the art that the present utility model is not limited to the embodiments described above, and that the above embodiments and descriptions are merely illustrative of the principles of the present utility model, and various changes and modifications may be made without departing from the spirit and scope of the utility model, which is defined in the appended claims. The scope of the utility model is defined by the appended claims and equivalents thereof.

Claims (10)

1. The micro display light engine is characterized by comprising a micro-LED panel, cooling liquid (21), a thin lens (22), a metal frame (23), a connecting column (24) and a projection lens;

the micro-LED panel comprises a substrate (1), a plurality of micro-LED crystal grains (11) with luminous pixels, a glass plate (12), a metal bracket (13), a sealing frame (14), a radiator (15), filling glue (16) and transparent heat-conducting glue (17);

The sealing frame (14) is square-tube-shaped, and the length and width dimensions of the section of the sealing frame (14) are equal to those of the glass plate (12); the substrate (1), the sealing frame (14) and the incidence surface of the glass plate (12) are sequentially attached; the micro-LED packaging structure is characterized in that the micro-LED packaging structure is positioned among the substrate (1), the sealing frame (14) and the glass plate (12), and a plurality of micro-LED crystal grains (11) and a driving circuit used for carrying out one-to-one addressing on the micro-LED crystal grains (11) are arranged on the substrate (1); electrodes of the micro-LED crystal grains (11) are bonded with the driving circuit arranged on the substrate (1); the electrodes of the micro-LED crystal grains (11) are of a flip-chip structure;

the length of the sealing frame (14) is 6-10 mu m larger than the height value of the top surface of the micro-LED crystal grains (11) higher than the surface of the substrate (1);

the luminous colors of the micro-LED crystal grains (11) are single primary colors, double primary colors or three primary colors;

the metal frame (23) is tubular, one end of the metal frame (23) is attached to the emergent surface of the glass plate (12), and the other end of the metal frame is connected with the thin lens (22) to form a closed cavity; the closed cavity is filled with the cooling liquid (21); -said glass plate (12), said cooling liquid (21) and said thin lens (22) constitute a liquid lens;

The metal bracket (13) covers one end of the substrate (1), the sealing frame (14), the glass plate (12) and the metal frame (23), and the substrate (1) is attached and mounted on the inner surface of the metal bracket (13); the filling glue (16) is filled among the metal frame (23), the glass plate (12) and the metal bracket (13); the radiator (15) is attached to the back of the metal bracket (13);

the emergent surface of the glass plate (12) is manufactured into a first black matrix (121) in a region except for a light emergent angle theta selected by a plurality of micro-LED crystal grains (11);

the incidence surface of the glass plate (12) is manufactured into a second black matrix (122) in the area except the light emergent angle theta selected by the micro-LED crystal grains (11);

the incidence surface of the glass plate (12) is provided with the transparent heat-conducting glue (17) in the area opposite to the micro-LED crystal grains (11), and the top surfaces of the micro-LED crystal grains (11), the transparent heat-conducting glue (17) and the incidence surface of the glass plate (12) are sequentially attached; the thickness of the transparent heat-conducting glue (17) is 10 mu m;

the projection lens comprises a lens outer cylinder (34), and an incident lens group (31), an intermediate lens group (32) and an emergent lens group (33) which are arranged in the lens outer cylinder (34) and are sequentially arranged according to the light travelling direction; the entrance lens group (31), the intermediate lens group (32) and the exit lens group (33) each comprise at least one lens; the metal bracket (13) is connected with the lens outer cylinder (34) through the connecting column (24); the number of the connecting posts (24) is at least three or more;

And Fno after the liquid lens and the projection lens are combined is less than or equal to 1.2.

2. A micro-display light engine as claimed in claim 1, characterized in that the glass plate (12) is made of an optical crystal.

3. A micro-display light engine according to claim 1, wherein the incident lens group (31) comprises a first lens (311) and a second lens (312) arranged in order in the direction of light travel; the number of the lenses of the middle lens group (32) is one; the exit lens group (33) includes a fourth lens (331) and a fifth lens (332) which are disposed in this order in the light traveling direction.

4. A micro-display light engine according to claim 1, characterized in that the thin lens (22) is concave-convex, the convex surface being opposite to the glass plate (12); the convex surface and the concave surface of the thin lens (22) are one or the combination of any two of free-form surfaces, aspheric surfaces and spherical surfaces;

the thickness of the thin lens (22) is equal or unequal from the center to the edge;

the surface shape of the light-passing surface of the concave surface of the thin lens (22) is as follows: when the angles of the light rays emitted by the micro-LED crystal grains (11) are larger than the limitation of the FNO value on the angles of the light rays, the light rays larger than the FNO value limitation angle are totally reflected at the concave surface.

5. A micro-display light engine according to claim 1, characterized in that the absolute value of the difference between the refractive indices of the cooling liquid (21) and the thin lens (22) is equal to or less than 0.2; the absolute value of the difference between the refractive indices of the cooling liquid (21) and the glass plate (12) is not more than 0.3.

6. A micro-display light engine according to claim 1, characterized in that the filler glue (16) is silicone rubber.

7. A micro-display light engine according to claim 1, characterized in that the transparent heat-conducting glue (17) is an optical grade silica gel.

8. A single-engine full-color projector, characterized by comprising the micro-display light engine according to any one of claims 1-7, wherein the number of the micro-display light engines is one, and the light emission color of a plurality of micro-LED dies (11) included in the micro-display light engine is three primary colors.

9. A dual-engine full-color projector, characterized by comprising the micro-display light engines of any one of claims 1-7, wherein the number of the micro-display light engines is two, when the light emission color of a plurality of micro-LED dies (11) included in a first micro-display light engine (341) is a single primary color, the light emission color of a plurality of micro-LED dies (11) included in a second micro-display light engine (342) is a dual primary color, and the two primary colors of the second micro-display light engine (342) are not included in the light emission color of the first micro-display light engine (341); the two micro-display light engines (341, 342) are arranged at an angle a or are arranged in parallel, wherein the angle a is less than or equal to 14 degrees;

When the two micro display light engines (341, 342) are arranged in parallel, the two micro display light engines (341, 342) are arranged in an off-axis manner; the first micro display optical engine (341) is offset by d from the second micro display optical engine (342), and the second micro display optical engine (342) is offset by e from the first micro display optical engine (341); let the optical axis of the first micro-LED panel (131) included in the first micro-display light engine (341) be L51, the optical axis of the second micro-LED panel (132) included in the second micro-display light engine (342) be L55, the distance between the optical axis L51 and the optical axis L55 be c, and the projection magnification of the two micro-display light engines (341, 342) be β, c=β (d+e).

10. A three-engine full-color projector, characterized by comprising the micro-display light engine according to any one of claims 1-7, wherein the number of the micro-display light engines is three, and each micro-display light engine comprises a plurality of micro-LED crystal grains (11) with light emission color being one of three primary colors;

the first micro-display light engine (343) and the middle micro-display light engine (344) are arranged at an angle b/2, and the third micro-display light engine (345) and the middle micro-display light engine (344) are arranged at an angle b/2, wherein the angle b is less than or equal to 28 degrees;

Or three micro display light engines (343, 344, 345) are arranged in parallel, and two micro display light engines (343, 345) on two sides are distributed: the first micro-display optical engine (343) is offset by g towards the middle micro-display optical engine (344), and the third micro-display optical engine (345) is offset by k towards the middle micro-display optical engine (344); let the optical axis of the first micro-LED panel (133) included in the first micro-display light engine (343) be L61, the optical axis of the second micro-LED panel (134) included in the intermediate micro-display light engine (344) be L62, the distance between the optical axis L61 and the optical axis L62 be f, and the projection magnification of the two micro-display light engines (343, 344) be β, f=βg; let the optical axis of the third micro-LED panel (135) included in the third micro-display light engine (345) be L63, the distance between the optical axis L63 and the optical axis L62 be j, and the projection magnification of the two micro-display light engines (345, 344) be β, j=βk.

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