CN113701065A

CN113701065A - Combined light source collector and design method thereof

Info

Publication number: CN113701065A
Application number: CN202110991823.5A
Authority: CN
Inventors: 张锦
Original assignee: Luxnpro Chengdu Electronics Co ltd
Current assignee: Chengdu Jiutian Huaxin Technology Co Ltd
Priority date: 2021-08-26
Filing date: 2021-08-26
Publication date: 2021-11-26

Abstract

The invention discloses a combined light source collector and a design method thereof, relates to the technical field of optics, and solves the technical problem of uneven light distribution emitted by the existing light emergent surface; outside the collector, there is a separate device, which is a reflection type free-form surface reflector to collect the incident light with large angle; the invention ensures that the illumination of the emergent light of the whole collector is relatively uniform, and meets the requirement of a display device on a light field.

Description

Combined light source collector and design method thereof

Technical Field

The invention relates to the technical field of optics, in particular to the technical field of a combined light source collector.

Background

The high-power LED chip can be used for illumination, the luminous efficiency of the high-power LED chip exceeds that of an incandescent lamp, and the LED has the remarkable advantages of small volume, high efficiency, energy conservation, environmental protection, long service life, high response speed, vibration resistance, easiness in maintenance and the like, and is bound to be applied to the field of illumination. And an illumination system designed for the characteristics of the projector has also been widely used.

Currently, a rectangular illumination spot is required in projection illumination to illuminate a DMD display, either LCOS or LCD. However, due to the very different characteristics of display devices, in illumination systems illuminating micro-display devices such as DMD and LCOS, as well as illuminating large display devices such as LCD, although the performance requirements for the light source are the same, the design of the illumination system varies greatly because the display devices vary greatly, and their display areas vary by orders of magnitude.

In the case of patent CN 112856334 a, in the lighting system of the closed system, the lighting system uses a white LED light source, and uses a light cone composed of planes with four reflecting surfaces. The small end of the light cone is an LED light source, and the large end of the light cone is a light emergent end. Often at the exit end, there is also a fresnel lens. The fresnel lens acts to collimate the light. Therefore, such an illumination system has disadvantages of large size, low collection efficiency, and large difference between the edge illuminance and the center illuminance.

Meanwhile, since the whole light cone provides an illumination light field for the display device, the modulation of light rays in a LOCAL area cannot be supported, so that dynamic backlight adjustment cannot be realized, and the function of LOCAL DIMMING (LOCAL backlight adjustment) cannot be realized.

Patent CN 107490816 a discloses a total reflection fresnel lens, which includes a lens body, one side of the lens body is a plane, the center of the other side is a convex lens, the outer side of the convex lens is provided with a plurality of ring-shaped collapse structures, incident light emitted from a light source is refracted and deflected firstly by the ring-shaped collapse structures and then totally reflected to obtain emergent light, and the emergent light is emitted from the plane of the lens body in parallel. The light source is located at the center of the convex lens, and although the emergent light rays can be emitted out of the plane of the lens body in parallel, because the included angle (also called radiation angle) between the light rays emitted by the light source and the center of the light source is different, the illumination intensity distribution on the plane of the lens body is not uniform, and the farther away from the center of the light source, the lower the radiation capability of the LED light source is, and the lower the illumination intensity of the light is. And the patent does not consider and does not support the collection of the light rays with large angles, so the problem of low efficiency exists.

Disclosure of Invention

The invention aims to: in order to solve the above technical problems, the present invention provides a combined light source collector.

The invention specifically adopts the following technical scheme for realizing the purpose:

a combined light source collector comprises a light condensing unit, an emergent unit, a light collecting unit and a reflecting unit, wherein the light condensing unit is arranged on the light condensing unit;

the light gathering unit and the light gathering unit are arranged adjacently and are both parallel to the emergent unit, a reflecting unit is arranged on the vertical surface of the emergent unit close to the light gathering unit,

the ray path of the collector comprises;

small-angle incident light rays in the LED light source become collimated light rays after passing through the light condensing unit, and the collimated light rays are emitted out of the light emitting unit in parallel to form a central aperture with the area of S1;

the middle-angle incident light in the LED light source becomes nearly collimated light after passing through the light collecting unit and is emitted out of the emergent unit in parallel to form an outer ring aperture with the area of S2;

after passing through the reflection unit, the large-angle incident light in the LED light source passes through the light collection unit and finally becomes nearly collimated light and is parallelly emitted out of the emergent unit, and all the light is emitted out of the outer ring light ring;

the LED light source is arranged on the central line of the light condensation unit and is away from the focus position of the light condensation unit or the position close to the focus position.

Furthermore, the light condensing unit is a convex lens, the light condensing unit is a total reflection type Fresnel lens, the reflecting unit is a free-form surface reflector, and the emergent unit is a light emergent surface.

Further, the outer ring aperture is concentric with the center aperture, and the area of the outer ring aperture S2 is equal to the area of the center aperture S1.

Further, the small-angle incident light refers to all the emergent light rays of the LED light source, wherein the radiation angle theta of the light source is less than or equal to 1/2 luminous flux angle alpha;

the medium-angle incident ray refers to all emergent rays of which the radiation angle theta is larger than 1/2 light flux angle alpha and is not larger than the radiation angle beta;

the large-angle incident light refers to the outgoing light with the radiation angle theta from all large angles of the radiation angle beta-90 degrees.

Further, the radiation angle β is calculated as follows: after the area of the outer ring aperture S2 is determined, the radius of the outer ring aperture S2 is calculated, and the included angle from the outer edge of the radius relative to the position of the LED light source is the radiation angle beta.

Further, the included angle between the edge of the convex lens and the LED light source is equal to 1/2 luminous flux angle alpha, and the 1/2 luminous flux angle alpha is determined by the light distribution curve of the light source; 1/2 definition of the light flux angle α refers to: the light emitted from the LED light source has a luminous flux of 1/2 of the total luminous flux of the LED light source when the light is radiated at an angle α, which is 1/2 light flux angle α.

Further, the total reflection type Fresnel lens is composed of a plurality of annular collapse structures; the incident light with the middle angle firstly refracts and deflects through the annular collapse structure and then is totally reflected and collimated to irradiate the light emergent surface.

Furthermore, the diameters of the annular collapse structures are different, and each annular collapse structure comprises an incident surface and a total reflection surface; the incident surface is a conical surface generated by the rotation of a straight line segment through a central shaft, the total reflection surface is a drum conical surface generated by the rotation of a free curved surface meeting the total reflection condition of the refracted light through the central shaft, and the central shaft is the central line of the convex lens.

A design method of a combined light source collector comprises the following manufacturing steps,

step 1: determining 1/2 a luminous flux angle alpha according to a light distribution curve of the LED light source;

step 2: making small-angle incident light rays with the radiation angle smaller than 1/2 light flux angle alpha of the LED light source pass through the first optical device to become collimated light rays, and the collimated light rays are emitted out of the light ray emergent surface of the collector body in parallel, forming a central aperture on the light ray emergent surface, and measuring the area of the central aperture S1;

and step 3: determining an outer ring aperture area S2 concentrically arranged with the central aperture on the light exit surface according to the area S1 of the central aperture, wherein S1 is S2;

and 4, step 4: calculating the radius of the outer ring aperture S2 according to the area S2 of the outer ring aperture, and then determining the included angle of the outer edge of the radius relative to the position of the light source, wherein the included angle is defined as a radiation angle beta; at the moment, the incident light with the radiation angle larger than 1/2 luminous flux angle alpha and not larger than the radiation angle beta is a medium-angle incident light; the incident light with the radiation angle between beta and 90 degrees is a large-angle incident light;

and 5: collimating the incident light rays with a medium angle to emit to the outer ring aperture by adopting a second optical device;

step 6: and after the third optical device is adopted to collect and reflect the large-angle incident light, the light is collimated by the second optical device and is emitted to the outer ring aperture.

Further, the first optical device is a convex lens, the second optical device is a total reflection type Fresnel lens, and the third optical device is a free-form surface reflector with a reflection unit.

The invention has the following beneficial effects:

1. the LED light source device can efficiently collect light rays of the LED light source, can collect and utilize all light rays emitted by the LED light source by 100% theoretically, can not collect large-angle light rays which can not be effectively utilized by a plurality of other collectors, can not form stray light after the collected light rays are arranged and are effectively collimated, and meanwhile, the physical size length of an illuminating system of the LCD liquid crystal projector can be greatly reduced.

2. The collector has the light shaping effect, can perform light collimation, is used for the illumination system of the projector, can replace a Fresnel collimation lens in the illumination system of the traditional LCD projector, saves the cost and reduces the process difficulty.

3. The LED light source is positioned closer to the collimating lens, i.e. the focal length is smaller. In the projection utilization, the space can be effectively saved. The remaining 1/2 luminous flux is difficult to collect and utilize due to the large angle, and different treatment modes are performed, specifically as follows: the middle-angle light adopts a total reflection type design logic, and the total reflection type design can be used for collimation under the condition that the position and the focal length of the light source are determined; because of the illumination uniformity, the collimated medium angle light is as large in area as the small angle light, and therefore a large amount of light cannot be collected. This portion of the light that cannot be collected is defined as high angle light. The large-angle light rays are totally concentrated in the middle-angle light ray area by a reflection method. Thereby achieving the total concentration of the additional 1/2 light flux in the medium angle ray region. Therefore, the illuminance uniformity is good.

4. Compared with the traditional collector product for projector backlighting, the collector product has obvious cutoff lines and higher illumination uniformity. The lens not only keeps a good illumination field, but also keeps the direction and the directionality of light rays, participates in the imaging system at the rear end, and has high uniformity in the illumination field; outside the illumination field, the light is significantly reduced and eventually disappears. Thus, adaptation to the projection industry itself improves collection efficiency, reduces optical losses, and reduces the likelihood of optical contamination due to extensive illumination. Therefore, the invention has optical properties which are quite different from the traditional LED illumination lens design and the traditional LED illumination backlight lens and light equalizing device design of the liquid crystal television.

Drawings

FIG. 1 is a schematic structural view of the present invention;

FIG. 2 is a schematic view of the ray path structure of the present invention;

FIG. 3 is a schematic view showing the structure of the liquid crystal panel of example 2 for providing an illumination field;

FIG. 4 is a polar light distribution curve for a light source according to the present invention;

FIG. 5 is a rectangular light distribution curve of the light source of the present invention;

reference numerals: 1-collector, 2-LED light source, 11-light emergent surface, 12-convex lens, 13-total reflection Fresnel lens, 14-free curved surface reflector and 131-incident surface; 132-total reflection surface; 301-incident light; 302-refracting light; 303-outgoing light rays.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. The components of embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.

Thus, the following detailed description of the embodiments of the present invention, presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example 1

As shown in fig. 4, the light flux angle α can be calculated 1/2 from the light distribution curve of fig. 4, which is a polar light distribution curve of the light source, and fig. 5, which is a rectangular light distribution curve of the light source; the cross-sectional area of the light distribution curve of fig. 5 and the wall on the abscissa represents the luminous flux, and it is found by calculation that the area of the cross-section within 30 ° is almost equal to the area of the cross-section other than 30 °, so that the 1/2 luminous flux angle α of the light source employed in the present embodiment is 30 °, and all the LED light source outgoing rays defining the light source radiation angle θ equal to or less than 1/2 luminous flux angle α are small-angle incident rays.

Referring to fig. 2 and 3, a combined light source collector includes a light condensing unit, an emitting unit, a light collecting unit and a reflecting unit, wherein;

the light path of the collector 1 comprises; incident light rays 301 emitted by the LED light source 2 pass through an optical device and then are changed into emergent light rays 303, wherein the incident light rays 301 are divided into three types according to angles; the large-angle incident light also passes through the reflection unit to form a refracted light 302, which is as follows:

small-angle incident light rays in the LED light source 2 pass through the light condensing unit to become collimated light rays and parallelly emit the collimated light rays out of the emergent unit to form a central aperture with the area of S1; the middle-angle incident light in the LED light source 2 becomes nearly collimated light after passing through the light collecting unit and is emitted out of the emergent unit in parallel to form an outer ring aperture with the area of S2; after passing through the reflection unit, the large-angle incident light in the LED light source 2 passes through the light collection unit and finally becomes nearly collimated light, and the light is emitted out of the emergent unit in parallel, and all the light is emitted out of the outer ring light ring; the LED light source 2 is arranged on the central line of the light condensing unit and is positioned at a distance from the focal position of the light condensing unit or near the focal position.

When in use: in the case of a conventional illumination system for a projector using a condenser system or using a cone system, the volume thereof is determined by the illumination system. The length of the illumination system is substantially close to the diagonal of the size of the liquid crystal screen. For example, a 6 "lcd projector would give a relatively good illumination field system, and the height of the cone would be about 12 cm. However, if the lens of the present invention is used, the height of the lens can be designed to be 6 cm, which is shorter. The space requirement can be greatly reduced.

As shown in fig. 4, according to the characteristics of the rectangular picture of the projector, the outer ring aperture is a virtual circle, an inner tangent rectangle, the edge of the rectangle is wireless close to the virtual circle of the central aperture,

the rectangle connected in the collector is an illumination light spot, and the size of the collector body can be reversely deduced according to the illumination light spot; on the long side of the illumination spot, there is a longer reflecting surface that needs to be inwardly convergent for internal reflection. And the basic shape is an ellipsoid shape or some special surface shape. The basic purpose is to reflect all the light on this side to the collector body; the reflector is clamped on the collector body, and the top view of the collector body presents a rectangular picture shape and is completely and perfectly buckled on the display device. The size of the light-emitting surface is rectangular, the light-emitting surface does not need any Fresnel lens, and the light-emitting surface is collimated and then projected onto a display device;

in addition, because the central aperture and the outer ring aperture are small in size and short in focal length, the central aperture and the outer ring aperture can be used independently or in combination, and a rectangular collimation illumination collecting device can be formed in a far field.

Example 2

In example 1, the LED light source 2 is provided on the center line of the convex lens 12 at a distance from the focal position of the convex lens or in the vicinity of the focal position. Specifically, the LED light source 2 is located on the side of the total reflection fresnel lens 13 where the ring-shaped collapsed structure is located. The light emitted by the LED light source 2 also directly passes through the convex lens 12;

preferably, the shape of the free-form surface reflector 14 is designed according to actual needs, and may be any shape, such as an arc shape, a rectangular shape, or a shape formed by combining an arc shape and a rectangular shape;

preferably, the included angle between the edge of the convex lens 12 and the center of the LED light source 2 is equal to 1/2 luminous flux angle α, so as to ensure that the incident angles of the incident light rays passing through the convex lens 12 are all smaller than 1/2 luminous flux angle α, save materials and reduce cost;

the total reflection type fresnel lens 13 is composed of a plurality of annular collapse structures, and medium-angle incident light rays firstly refract and deflect and then are totally reflected and collimated to irradiate the light ray exit surface 11 through the annular collapse structures. Therefore, the thickness of the collector is as thin as possible, and each ring like a total reflection lens is incident and refracted, then reflected by a total reflection curved surface, then converged as much as possible and collimated and emitted from a light emitting surface.

Preferably, the diameters of the ring-shaped collapsible structures are different, each ring-shaped collapsible structure includes an incident surface 131 and a total reflection surface 132, in this embodiment, an included angle between the incident surface 131 and a vertical plane is set to be 1 °, and a medium-angle incident light ray 301 is refracted by the incident surface 131, enters the medium surface, is reflected by the total reflection surface 132 via a path of a refracted light ray 302, and is collimated by a path of an emergent light ray 303 to be emitted from the light ray exit surface 11. The incident surface 131 is a conical surface generated by rotating a straight line segment through a central axis, the total reflection surface 132 is a drum conical surface generated by rotating a free curved surface satisfying the total reflection condition of the refracted light through the central axis, and the central axis is the central axis of the convex lens 12. Each annular collapsing structure has a gradually increasing pitch from center to edge, with one ring being larger than one ring. Because the pitch near the axis ring is too small, the convex lens 12 with a focal point coincident with the LED light source 2 is used to replace the part near the axis in consideration of the processing technology.

The tooth height of the first annular collapse structure adjacent to the convex lens 12 depends on the size of the light emitting point of the LED light source 2 and the light emitting angle required by the design; after the tooth height of the first annular collapse structure is set, the pitch of the first annular collapse structure and the oblique angle of the incident surface 131 of the first annular collapse structure are set by a processing technology, so that a curved surface meeting the tooth height total reflection condition of the first annular collapse structure is obtained, the incident light 301 passing through the tooth height vertex of the first annular collapse structure is refracted and then can intersect with the total reflection surface 132, the intersection point is set to be the vertex of the tooth height of the second annular collapse structure, the incident light 301 passing through the tooth height vertex of the second annular collapse structure is refracted and then can intersect with the total reflection surface 132, the intersection point is set to be the vertex of the tooth height of the third annular collapse structure, and the tooth height of each annular collapse structure is set in sequence.

Example 3

When the optical lens is used, the first optical device is a convex lens, the second optical device is a total reflection type Fresnel lens, and the third optical device is a free-form surface reflector with a reflection unit.

The free-form surface reflector is a bucket-shaped device in overall view, and all four surfaces are free-form surfaces. The two surfaces are used for reflecting large-angle light rays and projecting the large-angle light rays to an S2 area to realize uniformity and collimation; the two outer surfaces are regions where all light is reflected back to S1 and S2. These rays include part of the low angle rays, part of the medium angle rays and part of the high angle rays.

The collector of the application enables the formation area of the small-angle incident light collimation shooting light emergent surface to be S₁The small-angle incident light refers to all the emergent light rays of the LED light source with the radiation angle theta smaller than 1/2 luminous flux angle alpha, which means that the emergent light rays of the LED light source are divided into two parts with the same luminous flux according to the size of the luminous flux, wherein the radiation angle is smaller than 1/2, namely the small-angle incident light rays are collimated and emitted to the light ray emergent surface in parallel after passing through the convex lens to form the area S₁The central aperture of (1); the other part of the emergent light of the light source is divided into a medium-angle incident light and a large-angle incident light according to different incident angles of the light source, wherein the medium-angle incident light is ensured to be collimated to a light emergent surface after passing through a total reflection Fresnel lens so as to form an area S₂And the area S of the outer ring aperture₂Equal to the area S of the central aperture₁(ii) a Finally, in order to ensure uniform light flux distribution on the light ray outgoing surface, the large-angle incident light rays are collected and reflected by the free-form surface reflector, and then are collimated and emitted from the total reflection type Fresnel lens, and the light rays are uniformly emitted to the S₂So that light source exit rays having a radiation angle greater than 1/2 light flux angle alpha are collimated into an outer ring aperture having an area equal to the area of the central aperture. Because the area of the central aperture is equal to that of the outer ring aperture, and the luminous flux of the central aperture is equal to that of the outer ring apertureThe luminous flux in the ring is also the same, so that the illumination of emergent rays of the whole collector is ensured to be more uniform, and the requirement of a display device on a light field is met.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. The combined light source collector comprises a light condensing unit and an emergent unit, and is characterized by also comprising a light collecting unit and a reflecting unit, wherein the light condensing unit is arranged on the light condensing unit;

the light path of the collector (1) comprises;

small-angle incident light rays in the LED light source (2) pass through the light condensing unit and then become collimated light rays, and the collimated light rays are emitted out of the emergent unit in parallel to form a central aperture with the area of S1;

the middle-angle incident light in the LED light source (2) becomes a nearly collimated light after passing through the light collecting unit and is emitted out of the light emitting unit in parallel to form an outer ring diaphragm with the area of S2;

after passing through the reflection unit, the large-angle incident light in the LED light source (2) passes through the light collection unit and finally becomes nearly collimated light, and the light is emitted out of the emergent unit in parallel, and all the light is emitted out of the outer ring light ring;

the LED light source (2) is arranged on the central line of the light condensation unit and is away from the focus position of the light condensation unit or close to the focus position.

2. The combined light source collector of claim 1, wherein the light gathering unit is a convex lens (12), the light gathering unit is a total reflection type Fresnel lens (13), the reflection unit is a free-form surface reflector (14), and the exit unit is a light exit surface (11).

3. The combination light source collector as claimed in claim 2, wherein the outer ring aperture is concentric with the central aperture, and the area of the outer ring aperture S2 is equal to the area of the central aperture S1.

4. The combination light source collector of claim 2, wherein the low angle incidence rays are all LED light source emergent rays having a light source radiation angle θ less than or equal to 1/2 luminous flux angle α;

5. The combination light source collector of claim 4, wherein the radiation angle β is calculated as follows: after the area of the outer ring aperture S2 is determined, the radius of the outer ring aperture S2 is calculated, and the included angle from the outer edge of the radius relative to the position of the LED light source is the radiation angle beta.

6. The combination light source collector as claimed in claim 4, wherein the edge of the convex lens (12) is at an angle equal to 1/2 luminous flux angle α with respect to the LED light source (2), the 1/2 luminous flux angle α being determined by the light distribution curve of the light source; 1/2 definition of the light flux angle α refers to: the light emitted from the LED light source has a luminous flux of 1/2 of the total luminous flux of the LED light source when the light is radiated at an angle α, which is 1/2 light flux angle α.

7. The combination light source collector according to claim 4, wherein the total reflection type Fresnel lens (13) is composed of a plurality of annular collapsed structures; the incident light with the medium angle firstly refracts and deflects through the annular collapse structure, and then is totally reflected and collimated to irradiate the light emergent surface (11).

8. The combination light source collector as claimed in claim 7, wherein each ring-shaped collapsing structure has a different diameter, the ring-shaped collapsing structure comprises an incident surface (131) and a total reflection surface (132); the incident surface (131) is a conical surface generated by rotating a straight line segment through a central shaft, the total reflection surface (132) is a drum conical surface generated by rotating a free curved surface meeting the total reflection condition of the refracted light through the central shaft, and the central shaft is the central line of the convex lens (12).

9. A design method of a combined light source collector is characterized by comprising the following manufacturing steps,

step 1: determining 1/2 a luminous flux angle alpha according to a light distribution curve of the LED light source (2);

step 2: making small-angle incident light rays with the radiation angle smaller than 1/2 light flux angle alpha of the LED light source (2) pass through a first optical device to become collimated light rays, and the collimated light rays are emitted out of a light ray outgoing surface (11) of the collector body in parallel, forming a central aperture on the light ray outgoing surface (11), and measuring the area S1 of the central aperture;

and step 3: determining an outer ring aperture area S2 arranged concentrically with the central aperture on the light exit surface (11) according to the area S1 of the central aperture, wherein S1 is S2;

10. The design method of a combined light source collector as claimed in claim 9, wherein the first optical device is a convex lens (12), the second optical device is a total reflection type fresnel lens (13), and the third optical device is a free-form surface reflector (14).