CN111856853A - A micro-lens array projection system with compound micro-prism - Google Patents

Abstract

The invention provides a micro-lens array projection system of a composite micro-prism, which comprises a light source, a composite collimating mirror module, a projection source, a composite projection mirror module and a receiving surface which are sequentially arranged, wherein the composite collimating mirror module comprises a collimation and light-gathering surface and a first micro-lens array surface, the first micro-lens array surface comprises m first micro-lens units, and the projection source comprises m projection image units; the composite projection mirror module comprises a microprism array surface and a second microlens array surface, the microprism array surface is positioned on one side of the second microlens array surface close to the projection source, the microprism array surface comprises m wedge-shaped microprism units, and the second microlens array surface comprises m second microlens units; the wedge angle of the ith wedge-shaped microprism unit from the optical axis of the system satisfies the following relation:

the wedge-shaped microprism unit can realize targeted deflection on the object image unit, and finally, a clear and single projection real image is formed.

Description

A micro-lens array projection system with compound micro-prism

technical field

The invention relates to a projection system, and specifically discloses a microlens array projection system of a compound microprism.

Background technique

The projection system is an optical system that illuminates the object and images it on the projection screen. The short-distance projection system can be applied to the side of the car to welcome guests, to the front and rear of the car as a warning reminder, and can also be applied to desktop projection, such as keyboard image projection.

The projection system mainly includes three important components: light source, projection source and imaging unit. According to whether the image in the projection source appears repeatedly on the receiving surface, it is divided into single-channel projection system and multi-channel projection system.

As shown in Figure 1, the single-channel projection system is equipped with multi-piece imaging units, including projection sources such as LEDs, collimating lenses, film films, and projection unit lens groups, which can obtain high-definition projected real images at different distances. However, the depth of field is shallow, the number of lenses is large, and the overall length of the system is large.

The multi-channel projection system is shown in Figure 2, including a light source, a collimating lens, a first microlens array, a projection source and a second microlens array, which can achieve far-field imaging, but when the receiving surface is close, the microlens unit Compared with the image height of the projected real image, the height cannot be ignored. For example, when the ratio of the height of the microlens unit to the height of the projected real image is greater than 1/50, due to the offset of each imaging optical path, multiple images on the image surface will be caused. The image planes are superimposed on each other, resulting in the final inability to form a clear and single projected real image.

The projection system in the prior art cannot simultaneously achieve the performance of short-range projection, clear and single projected real image, and small total length of the system.

SUMMARY OF THE INVENTION

Based on this, it is necessary to address the problems of the prior art to provide a microlens array projection system with a compound microprism, which can achieve a clear and single projection effect at a short distance, and the total length of the system is small.

In order to solve the problems of the prior art, the present invention discloses a composite microprism microlens array projection system, comprising a light source, a composite collimating mirror module, a projection source, a composite projection mirror module and a receiving surface arranged in sequence, and the composite collimating mirror module It includes a collimating light collecting surface and a first microlens array surface, the collimating light collecting surface is located on the side of the first microlens array surface away from the projection source, and the first microlens array surface includes m first microlenses arranged in an array unit, the projection source includes m projection image units arranged in an array;

The composite projection mirror module includes a microprism array surface and a second microlens array surface, the microprism array surface is located on the side of the second microlens array surface close to the projection source, and the microprism array surface includes m wedge-shaped microprism units arranged in an array , the second microlens array surface includes m second microlens units arranged in an array, and each wedge-shaped microprism unit has a common central axis with the first microlens unit and the second microlens unit corresponding to both sides, and each The projection image units are respectively located on the central axis of each wedge-shaped microprism unit;

The distance between the first microlens array surface and the second microlens array surface is s, the distance between the microprism array surface and the receiving surface is L', the focal length of the first microlens unit f ₁ =s, the second microlens The focal length of the lens unit is f ₂ =(L'*s)/(L'+s);

The wedge angle of the wedge-shaped microprism unit is α _i , i*d<<L′, and the wedge angle of the i-th wedge-shaped microprism unit away from the optical axis of the system satisfies the following relationship:

Wherein, the distance between two adjacent first micro-lens units, the distance between two adjacent second micro-lens units, and the distance between two adjacent wedge-shaped micro-prism units are all d, and n is the refractive index.

Further, the collimating light collecting surface is arranged on the collimating lens, and the first microlens array surface is arranged on the first multi-channel lens.

Further, the first microlens array surface is located on the side of the first multi-channel lens away from the projection source, the side of the first multi-channel lens close to the projection source is a plane, and the projection source is in close contact with the plane of the first multi-channel lens.

Further, the projection source includes at least two projection image units having different projection images.

Further, the microprism array surface is arranged on the deflecting lens, and the second microlens array surface is arranged on the second multi-channel lens.

Further, both sides of the deflecting lens are provided with microprism array surfaces.

Further, the side of the deflection lens close to the projection source is a microprism array surface, and the side of the deflection lens away from the projection source is a plane; the side of the second multi-channel lens close to the receiving surface is a second microlens array surface, and the first The side of the second multi-channel lens away from the receiving surface is a plane, and the plane of the deflecting lens is in close contact with the plane of the second multi-channel lens.

Further, both the microprism array surface and the second microlens array surface are arranged on the projection composite lens.

The beneficial effects of the present invention are as follows: the present invention discloses a composite microprism microlens array projection system, which is provided with a first microlens array surface and a second microlens array surface, and the first microlens unit and the second microlens are opposite to each other. The units have a common optical axis, which can effectively avoid crosstalk of optical information between adjacent optical channels. A microprism array surface is arranged between the projection source and the second microlens array surface. The sub-object image unit of the lens unit realizes targeted deflection, and the deflected sub-object image unit passes through the second micro-lens unit to form a sub-real image unit. Finally, each sub-real image unit is compounded and overlapped on the receiving surface to form a clear and single image. Projecting a real image, the total length of the system is small and the structure is simple.

Description of drawings

FIG. 1 is a schematic diagram of an optical path structure of a single-channel projection system in the prior art.

FIG. 2 is a schematic diagram of an optical path structure of a multi-channel projection system in the prior art.

FIG. 3 is a schematic diagram of an optical path structure of the present invention.

FIG. 4 is a schematic diagram of a partial structure of the present invention.

FIG. 5 is a schematic diagram of an optical path structure according to an embodiment of the present invention.

FIG. 6 is a schematic diagram of an optical path structure according to another embodiment of the present invention.

FIG. 7 is a schematic diagram of an optical path structure according to another embodiment of the present invention.

Reference numerals are: light source 10, compound collimating lens module 20, collimating light collecting surface 21, collimating lens 21A, second microlens array surface 22, second microlens unit 221, first multi-channel lens 22A, projection Source 30, projection image unit 31, compound projection mirror module 40, microprism array surface 41, wedge-shaped microprism unit 411, deflection lens 41A, second microlens array surface 42, second microlens unit 421, second multi-channel Lens 42A, projection compound lens 43, receiving surface 50.

Detailed ways

In order to further understand the features, technical means, and specific goals and functions of the present invention, the present invention will be described in further detail below with reference to the accompanying drawings and specific embodiments.

Refer to FIGS. 3 to 7 .

The basic embodiment of the present invention discloses a composite microprism microlens array projection system, as shown in FIG. 3 , including a light source 10 , a composite collimator module 20 , a projection source 30 , a composite projection mirror module 40 and a receiving surface arranged in sequence 50. Preferably, the light source 10 can be an LED lamp bead, and the composite collimating lens module 20 includes a collimating light collecting surface 21 and a first microlens array surface 22. Preferably, the collimating light collecting surface 21 is a Aspherical surface, the collimating light collecting surface 21 is located on the side of the first microlens array surface 22 away from the projection source 30, the first microlens array surface 22 includes m first microlens units 221 arranged in an array, and the projection source 30 includes There are m projection image units 31 arranged in an array, the projection source 30 can be a film, a liquid crystal screen, etc., and the receiving surface 50 can be a wall, a ground, a white screen, etc.;

The composite projection mirror module 40 includes a microprism array surface 41 and a second microlens array surface 42, the microprism array surface 41 is located on the side of the second microlens array surface 42 close to the projection source 30, and the microprism array surface 41 includes m arrays Arranged wedge-shaped micro-prism units 411, the second micro-lens array surface 42 includes m second micro-lens units 421 arranged in an array, the cross-section of the wedge-shaped micro-prism units 411 is a right triangle, and each first micro-prism unit on the same horizontal position The lens unit 221, the micro-prism unit and the second micro-lens unit 421 are in one-to-one correspondence, and each wedge-shaped micro-prism unit 411 has a common central axis with the first micro-lens unit 221 and the second micro-lens unit 421 corresponding to both sides, respectively, It can effectively avoid the occurrence of optical information crosstalk between adjacent optical channels, resulting in the formation of ghosting of the final projected real image. Each projected image unit 31 is located on the central axis of each wedge-shaped microprism unit 411, and the first 221, the second micro-lens unit 421 and the wedge-shaped micro-prism unit 411 form an optical channel, and each projection image unit 31 is located in each optical channel;

As shown in FIG. 4 , the distance between the first microlens array surface 22 and the second microlens array surface 42 is s, the distance between the microprism array surface 41 and the receiving surface 50 is L′, and L′ is the projection distance , in order to ensure that the light collimated by the collimating condensing surface 21 can accurately reach the light channel corresponding to the second microlens unit 421 without cross light, the first microlens unit 221 is used as a field lens and its focus is set at the corresponding second microlens unit 421. The principal point of the micro-lens unit 421, the focal length of the first micro-lens unit 221 is f ₁ =s, and the focal length of the second micro-lens unit 421 is f ₂ =(L′*s)/(L′+s);

As shown in FIG. 4 , the parallel line of the optical axis of the overall system passes through the inclined surface of each wedge-shaped microprism unit 411, and the plane formed by the optical axis of any microlens unit and the optical axis of the system is perpendicular to the corresponding microlens unit. The slope of the wedge-shaped microprism unit 411, the wedge angle of the wedge-shaped microprism unit 411 is α _i , the wedge angle is the angle between the plane perpendicular to the optical axis of the system and the slope of the wedge-shaped microprism, in FIG. 4 , has the same central axis The included angle between the two inclined surfaces of the two wedge-shaped microprism units 411 is the wedge angle, the distance between the centers of two adjacent first microlens units 221, the distance between the centers of two adjacent second microlens units 421 and the The distance between the centers of the adjacent two wedge-shaped micro-prism units 411 is d, and n is the refractive index of the lens where the micro-prism array surface 41 is located. If the distance is sufficiently small, i*d<<L′, the incident angle I _i of the light is very small, and the incident angle of the light at the wedge-shaped microprism unit 411 is also very small, so the wedge angle α _i is also very small, Therefore, the sine value of the angle can be approximated as the angle radian, and the simplified declination formula is: δ _i =(n-1)*α _i , according to the geometric relationship in the figure, we can know that the declination angle δ _i =(i*d )/L′, the wedge angle of the wedge-shaped microprism unit 411 is α _i , i*d<<L′, combining the above two formulas, it can be concluded that the wedge angle of the i-th wedge-shaped microprism unit 411 from the optical axis of the system satisfies The following relationship:

Wherein, i takes an integer from 0 to m, i=0 is the center, and the unit of the above angle adopts the radian system.

The value obtained by the calculation of the above relational formula is the design reference value, which can be adjusted according to the actual situation in the specific application to adapt to the corresponding demand.

During operation, the light emitted by the light source 10 arrives at the collimating light collecting surface 21, the first microlens array surface 22, the projection source 30, the microprism array surface 41, the second microlens array surface 42 and the receiving surface 50 in sequence. The specific principle is as follows: : The light emitted by the light source 10 is collimated by the collimating and condensing surface 21 and then reaches the first microlens array surface 22, thereby forming m beam units, and each beam unit is selected and output by the corresponding projection image unit 31 to form m sub-objects After each sub-object image unit is deflected and adjusted by the corresponding wedge-shaped microprism unit 411, it enters each corresponding second microlens unit 421 to obtain m sub-real image units, and each sub-real image unit realizes compounding on the receiving surface 50 Superimpose, and finally obtain a clear projected real image. This system adjusts the deflection of the object image by adding a microprism array surface 41, and the object image in each optical channel can obtain independent deflection, and can realize the composite superposition of multi-channel optical path imaging for the projection system, so as to obtain Clear projected real image.

The composite projection mirror module is actually an optical adder from a mathematical point of view, and the illuminance distribution of the receiving surface 5050 satisfies the following relationship: E(x, y)=∑ _i=1..m E _i (x _i , y _i ) , where (x, y) is the position coordinate of the receiving surface 5050, E is the illuminance of the receiving surface 50, (x _i , y _i ) is the position coordinate of the projection source 30, and E _i (x _i , y _i ) is the projected image The illuminance of the unit 31 on the receiving surface 50.

In this embodiment, the collimating light-converging surface 21 is disposed on the collimating lens 21A, the first microlens array surface 22 is disposed on the first multi-channel lens 22A, and the collimating lens 21A is located on the first multi-channel lens 22A away from the projection On one side of the source 30, the first microlens unit 221 may be a plano-convex lens, a biconvex lens, a convex-plano lens or a meniscus lens, or even a combination of multiple microlenses.

Based on the above embodiment, the first microlens array surface 22 is located on the side of the first multi-channel lens 22A away from the projection source 30 , the side of the first multi-channel lens 22A close to the projection source 30 is a plane, and the projection source 30 and the first multi-channel lens 22A are flat. The planes of the channel lens 22A are in close contact, which can effectively improve the utilization rate of light energy by the projection source 30 and can effectively shorten the length of the overall system.

In this embodiment, the projection source 30 includes at least two types of projection image units 31 having different projection images. As shown in FIG. 5 , there are at least two types of projection image units 31 , and the projection images of different types of projection image units 31 are different. , and finally various sub-real image units with different formed images are compounded and superimposed on the receiving surface 50 to form a specific projected real image of the image.

In this embodiment, as shown in FIGS. 3 , 5 and 6 , a deflection lens 41A and a second multi-channel lens 42A are provided between the projection source 30 and the receiving surface 50 , and the second multi-channel lens 42A is located at the deflection lens 41A On the side away from the receiving surface 50, the microprism array surface 41 is provided on the deflecting lens 41A, and the microprism array surface 41 can be located on either side of the deflecting lens 41A. The thickness of the deflecting lens 41A is small, which can effectively shorten the system time. The total length, the second micro-lens array surface 42 is disposed on the second multi-channel lens 42A, the second micro-lens array surface 42 can be located on either side of the second multi-channel lens 42A, and the light selected by the projection source 30 passes through in sequence The microprism array surface 41 and the second microlens array surface 42, and the second microlens unit 421 can be a plano-convex lens, a biconvex lens, a convex-plano lens or a meniscus lens, or even a combination of multiple microlenses.

Based on the above-mentioned embodiment, as shown in FIGS. 3 , 4 and 5 , both sides of the deflecting lens 41A are provided with microprism array surfaces 41 , that is, there are two microprism array surfaces 41 , and the two microprism array surfaces 41 are respectively The microprism array surfaces 41 on both sides of the deflection lens 41A are symmetrical with respect to the deflection lens 41A, and the included angle between the two inclined surfaces of the two wedge-shaped microprism units 411 having the same central axis is a wedge angle.

In this embodiment, as shown in FIG. 6 , the side of the deflection lens 41A close to the projection source 30 is the microprism array surface 41 , and the side of the deflection lens 41A away from the projection source 30 is a plane; the second multi-channel lens 42A The side close to the receiving surface 50 is the second microlens array surface 42 , the side of the second multi-channel lens 42A away from the receiving surface 50 is a plane, and the plane of the deflecting lens 41A is in close contact with the plane of the second multi-channel lens 42A , can further improve the utilization rate of light energy, and can effectively shorten the length of the system.

In this embodiment, as shown in FIG. 7 , a projection compound lens 43 is provided between the projection source 30 and the receiving surface 50 , and the microprism array surface 41 and the second microlens array surface 42 are both arranged on the projection compound lens 43 . That is, the microprism array surface 41 and the second microlens array surface 42 are respectively located on the two surfaces of the projection composite lens 43, which can effectively reduce the number of optical parts of the system, the system structure is simple, the system cost is low, and because the optical parts will affect the light energy. The system reduces the use of optical parts and can also effectively reduce the loss of light energy, thereby improving the utilization rate of light energy; Further simplify the system structure and reduce light energy loss.

The above-mentioned embodiments only represent several embodiments of the present invention, and the descriptions thereof are specific and detailed, but should not be construed as a limitation on the scope of the patent of the present invention. It should be pointed out that for those skilled in the art, without departing from the concept of the present invention, several modifications and improvements can be made, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention should be subject to the appended claims.

Claims (8)

1. A microlens array projection system of a composite microprism, characterized in that it comprises a light source (10), a composite collimator module (20), a projection source (30), a composite projection mirror module (40) and A receiving surface (50), the composite collimating lens module (20) includes a collimating light-converging surface (21) and a first microlens array surface (22), and the collimating light-converging surface (21) is located on the first microlens array surface (22). A side of a microlens array surface (22) away from the projection source (30), the first microlens array surface (22) includes m first microlens units (221) arranged in an array, and the projection source (30) including m projection image units (31) arranged in an array; The composite projection mirror module (40) includes a microprism array surface (41) and a second microlens array surface (42), the microprism array surface (41) is located on the second microlens array surface (42) close to the projection source On one side of (30), the microprism array surface (41) includes m wedge-shaped microprism units (411) arranged in an array, and the second microlens array surface (42) includes m number of first microprism units (411) arranged in an array. Two micro-lens units (421), each of the wedge-shaped micro-prism units (411) has a common central axis with the first micro-lens unit (221) and the second micro-lens unit (421) corresponding to both sides, respectively, and each The projected image units (31) are respectively located on the central axis of each of the wedge-shaped microprism units (411); The distance between the first microlens array surface (22) and the second microlens array surface (42) is s, and the distance between the microprism array surface (41) and the receiving surface (50) is s. The distance is L', the focal length of the first micro-lens unit (221) is f ₁ =s, and the focal length of the second micro-lens unit (421) is f ₂ =(L'*s)/(L'+s ); The wedge angle of the wedge-shaped microprism unit (411) is α _i , i*d<<L', and the wedge angle of the i-th wedge-shaped microprism unit (411) from the optical axis of the system satisfies the following relationship:

Wherein, the distance between two adjacent first micro-lens units (221), the distance between two adjacent second micro-lens units (421), and the distance between two adjacent wedge-shaped micro-prism units (411) The pitches are all d, and n is the refractive index. 2 . The microlens array projection system of a composite microprism according to claim 1 , wherein the collimating light-converging surface (21) is arranged on the collimating lens (21A), and the first microlens The lens array surface (22) is arranged on the first multi-channel lens (22A). 3 . The micro-lens array projection system of a compound micro-prism according to claim 2 , wherein the first micro-lens array surface ( 22 ) is located on the first multi-channel lens ( 22A) away from the One side of the projection source (30), the side of the first multi-channel lens (22A) close to the projection source (30) is a plane, the projection source (30) and the first multi-channel lens (22A) ) are in close contact with the plane. 4. A composite microprism microlens array projection system according to claim 1, wherein the projection source (30) comprises at least two projection image units (31) having different projection images. 5. The micro-lens array projection system of a composite micro-prism according to claim 1, wherein the micro-prism array surface (41) is arranged on the deflecting lens (41A), and the second micro-lens The array surface (42) is arranged on the second multi-channel lens (42A). 6 . The micro-lens array projection system of composite micro-prisms according to claim 5 , wherein the micro-prism array surfaces ( 41 ) are provided on both sides of the deflecting lens ( 41A ). 7 . 7 . The micro-lens array projection system of a composite micro-prism according to claim 5 , wherein the side of the deflecting lens ( 41A ) close to the projection source ( 30 ) is the micro-prism array. 8 . surface (41), the side of the deflecting lens (41A) away from the projection source (30) is a plane; the side of the second multi-channel lens (42A) close to the receiving surface (50) is the The second microlens array surface (42), the side of the second multi-channel lens (42A) away from the receiving surface (50) is a plane, and the plane of the deflecting lens (41A) is the same as the second The planes of the multi-channel lens (42A) are in close contact. 8. The micro-lens array projection system of a composite micro-prism according to claim 1, wherein the micro-prism array surface (41) and the second micro-lens array surface (42) are both provided in the projection on the compound lens (43).

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