CN103528023A - Designing scheme of light guide pipe with high light use ratio - Google Patents

Abstract

The invention discloses a designing scheme of a light guide pipe with a high light guide use ratio. The light guide pipe is mainly formed by a main light pipe, a plurality of branch pipes, a collecting light pipe and a convergent lens. Light emitted by light sources is collected to the main light pipe through the branch pipes then is irradiated to a DMD through the convergent lens, and light goes back into the main light pipe through the collecting light pipe after redundant light reflected by a digital lens in an off state is collected by a condenser. The condition which is met when the collecting light pipe reaches the maximum collecting rate is determined through calculation. The designing scheme has the advantages that 1. the collecting light pipe meeting the given condition can reach the best collecting efficiency, the light use ratio is increased, heat of a system is reduced, the service life of the system is prolonged, and the light guide pipe is more economical and practical; 2. the branch pipes enable multiple light sources to be transmitted at the same time, and are better matched with an LED light source; 3. the convergence convergent lens and the main light pipe are bonded together through an optical bonding agent, and loss of light in the transmission process is reduced.

Description

A kind of design of high light utilization efficiency light pipe

Technical field

The present invention generally relates to light pipe, and relates in particular to a kind of light pipe with the high-light-energy utilization rate of branched structure.

Background technology

Light pipe has been widely used projecting apparatus, in the various electronic products such as scanner.

Digital light is processed (Digital Light Processing) optical projection system, is called for short DLP optical projection system, adopts digital light treatment technology, has fine definition, image seamless, economy advantages of higher, has become the optical projection system of main flow on market.The core parts of digital light processing projection system are digital micromirror elements (Digital Micro mirror Device), referred to as DMD.It is integrated millions of micro mirrors on a chip, by microprocessor control, under the effect of electronic switch, each micro mirror can be turned to forward, reverse two positions by independent high frequency, microcontroller is controlled the time keeping after each micro mirror upset by pulse width size, produce the grey scale image of different brightness on screen.

In traditional digital light processing projection system, light transmits by light pipe, and light pipe has the effect of uniform beam, and the light that can guarantee to be irradiated on DMD is uniform light.Micro mirror on DMD when forward, i.e. " ON state ", light is reflected on projection screen; But the micro mirror on DMD when reverse, i.e. " OFF state ", light just can not arrive projection screen, this part light is unnecessary, generally adopts absorber that this part light is absorbed.The shortcoming of doing like this has two: the one, and this part light has been wasted, and light utilization efficiency is low; The 2nd, unnecessary light can produce heat after being absorbed body absorption, is unfavorable for entire system heat radiation.The light source of tradition in optical projection system generally adopts single light source luminous, but along with technology is constantly progressive, LED light source is little with its volume, life-span length, environmental protection and energy saving, design freedom are large etc., advantage progressively replaces traditional light source.Due to mono-luminous flux deficiency of LED, often adopt plurality of LEDs light source to meet the luminous flux requirement of system, so traditional light pipe just cannot mate with LED light source.So in traditional digital light processing projection system, can meet multiple light courcess and conduct in the urgent need to a kind of, the light pipe that the unnecessary light beam of DMD reflection can be recycled again simultaneously.

Existing technology can not realize above function, if application number is " 201020126921.X ", name is called the Chinese patent of " a kind of glass-mirror light guide pipe ", a kind of light pipe of high-performance low cost is proposed, but this light pipe can only be realized the straight line conduction of single light source light, can not realize the unnecessary light that multiple light courcess conducts simultaneously and collects DMD reflection.

Application number is " 01252803.X ", name is called the Chinese patent of " guiding device ", and application number is " 200420095017.1 ", name is called the Chinese patent of " light pipe ", the light pipe of a kind of arc and bending is proposed respectively, although they can realize the change of single light source radiation direction, can only conduct the light that single light source sends, can not realize the unnecessary light that multiple light courcess conducts simultaneously and collects DMD reflection.

Application number is " 200910300907.9 ", and name is called the Chinese patent of " light pipe and guiding device ", proposes to have the light pipe of a bright dipping end and a plurality of branched pipes, can realize a plurality of light sources and transmit simultaneously; Application number is " 201110107888.5 ", name is called the Chinese patent of " single LED two light pipes ", has proposed light beam that single light source sends and has assigned in a plurality of light pipes and go.Two kinds of above-mentioned methods all cannot realize the recycling to DMD reflection ray.

In above-mentioned technology, the first light pipe can only be realized the conduction of single light source straight line, and the scope of application is too narrow; The second and the third light pipe have been realized the change of light conduction direction, but can not meet LED as the system of light source; The 4th kind of light pipe realized multiple light courcess and conducted simultaneously, and the 5th kind of light pipe realized single light source shunting conduction, but for the system with digital micromirror elements, they all can not recycle the unnecessary light of digital micro-mirror reflection, and light utilization efficiency is low.Therefore in digital light processing projection system and other, have in the optical system of light pipe and digital micromirror elements, in the urgent need to a kind of multiple light courcess of can realizing, transmit simultaneously, the light pipe that the unnecessary light of digital micromirror elements reflection can be recycled again.

Summary of the invention

In order to solve above-mentioned technical barrier, the invention provides a kind of design of high light utilization efficiency light pipe.

The present invention solves the problems referred to above by following proposal:

A kind of design of high light utilization efficiency light pipe is mainly by key light pipe, a plurality of branched pipes, collecting light pipe and plus lens forms, the light that light source sends collects key light pipe by branched pipe, after convergent lens, be irradiated in digital micromirror elements again, after being collected by concentrator by the unnecessary light of digital micro-mirror " OFF state " reflection, by collecting pipe, get back to again in supervisor's light, collecting light pipe is comprised of four parts: with the coupling part of key light pipe, arch section, straight portion and compound parabolic concentrator, satisfied condition while collecting the maximum collection rate of light pipe by calculative determination,

Collect four partial common same optical axises of light pipe;

The critical angle of light pipe generation total reflection is , key light pipe with the angle of collecting light pipe coupling part is

, the radian of arch section is

, the maximum collection angle of compound parabolic concentrator is

, the angle of straight line portion and horizontal plane is

, all angles are all used Rad;

Collect the satisfied condition of light pipe:

;

Collect the radian of light pipe arch section

meet:

;

The satisfied condition of the maximum collection angle of compound parabolic concentrator: ;

The collection surface of compound parabolic concentrator faces by the light of digital micro-mirror " OFF state " reflection;

The quantity of collecting light pipe can be one, also can make a plurality ofly, and concrete quantity is determined by size and the quantity of digital micromirror elements;

The number of branched pipe is determined by quantity and the total light flux of light source;

The effective optical adhesive of plus lens and key light is bonded together.

Compared with prior art, beneficial effect is present design: 1. the collection light pipe that meets above-mentioned condition can reach best collection efficiency, has improved light utilization efficiency, has reduced the heat of system, has extended the life-span of system, practical more economically; 2. many branched pipes can meet a plurality of light sources and transmit simultaneously, better mate with LED light source; 3. with optical adhesive, plus lens and key light pipe are bonded together, reduce the loss of light in transmitting procedure.

Accompanying drawing explanation

Fig. 1 is whole light path schematic diagram.

Fig. 2 is the schematic diagram of compound parabolic concentrator.

Fig. 3 is the schematic diagram that compound parabolic concentrator is collected light.

Fig. 4 collects the schematic diagram that light pipe is collected light.

Fig. 5 collects another schematic diagram that light pipe is collected light.

Fig. 6 collects light pipe arch section schematic diagram.

Fig. 7 is the schematic diagram of plus lens.

1. branched pipes in figure, 2. key light pipe, 3. optical axis, 4. collects light pipe and key light pipe jointing part and divides, 5. the arch section of collecting pipe, 6. collect the straight portion of light pipe, 7. compound parabolic concentrator, 8. plus lens, 9. micro mirror, 10. micro mirror initial position, 11. planes of incidence, 12 exit facets, 13. normals.

The specific embodiment

Below in conjunction with accompanying drawing and example, tell about specific embodiments.

With reference to Fig. 1, in the present embodiment, there is the light that three LED light sources send to converge the laggard light pipe of becoming owner of through three branched pipes, after the even light of key light pipe, emergent ray is irradiated in digital micromirror elements by plus lens.Micro mirror overturns fast at+12 degree and-12 two positions of degree, when micro mirror be turned to+12 while spending, light is reflected to above projection screen; When micro mirror is turned to-12 while spending, light is reflected on compound parabolic concentrator, and concentrator gets up ray-collecting, and light comes back in key light pipe by collecting light pipe, and light completes and recycles.

In concrete enforcement, adopt the digital micromirror elements of other angles to be also fine, such as the flip angle of micro mirror be ± 10 to spend.

Fig. 2 is the schematic diagram of compound parabolic concentrator.Compound parabolic concentrator (Compound Parabolic Concentrator), be called for short CPC, a kind of according to the non-imaging concentrator of edge optics principle design, incident light arrives receiving surface by reflection in CPC, reach theoretical maximum optically focused ratio, performance is in close proximity to desirable concentrator.Plane of incidence radius is a, and exit facet radius is b, so the maximum collection angle of CPC

meet:

.If the angle of incident ray and optical axis is greater than , light will be reflected back by CPC, can not be collected; If the angle of incident ray and optical axis is less than

, light can be collected by CPC.The angle of light and optical axis is larger, and the uniformity that is collected light is lower, so the collection surface of compound parabolic concentrator should be faced by the light of digital micro-mirror " OFF state " reflection, to be collected the uniformity of light high in assurance like this.

With reference to Fig. 3, in the present embodiment, it is upper that light incides CPC, with the angle of the optical axis maximum collection angle that is CPC

, light is just in time collected, and enters in light pipe after primary event, and the angle of light and light pipe optical axis is also

.The condition that this light can transmit in light pipe is that total reflection occurs in light pipe,

, the condition that the maximum collection angle of concentrator will be satisfied is:

Fig. 4 collects the schematic diagram that light pipe is collected light.Light pipe has the character that does not change incident ray and optical axis included angle, and as Fig. 4, at light inlet, the angle in optical axis is incident ray

, light, after the transmission of light pipe, at the angle of light-emitting window and optical axis is still

.

With reference to Fig. 5, in the present embodiment, collect light pipe and formed by four parts: with coupling part, arch section, straight portion and the compound parabolic concentrator of key light pipe.The critical angle of light pipe generation total reflection is

, key light pipe with the angle of collecting light pipe coupling part is , the radian of arch section is

, the maximum collection angle of compound parabolic concentrator is

, the angle of straight line portion and horizontal plane is

.The angle of Ray Of Light and optical axis is the maximum collection angle of concentrator

, just by concentrator, collected, enter in light pipe, light pipe itself has the character that does not change light and optical axis included angle, with

enter light pipe, also with

go out light pipe.If the light of this collection can be utilized, require so it to enter in key light pipe and want total reflection can occur.The incidence angle of light in key light pipe is greater than critical angle

, in triangle ABC,

be greater than

, .

So collect light pipe, to satisfied condition be:

.

Fig. 6 collects light pipe arch section schematic diagram.Wherein

,

.The radian of arch section so

.The radian of collecting as can be seen here light pipe arch section by

with

common decision, the less light loss of radian is fewer, is guaranteeing under the prerequisite of collection efficiency increase

or reduce

can reduce light loss.

Fig. 7 is the schematic diagram of plus lens.Plus lens sticks on key light pipe with optical adhesive, reduces the loss of light in communication process.

Above-described embodiment is illustrative principle of the present invention and effect only; and the embodiment of part, for the person of ordinary skill of the art, without departing from the concept of the premise of the invention; can also make some distortion and improvement, these all belong to protection scope of the present invention.

Claims (1)

1. the design of a high light utilization efficiency light pipe is mainly by key light pipe, a plurality of branched pipes, collecting light pipe and plus lens forms, the light that light source sends collects key light pipe by branched pipe, after convergent lens, be irradiated in digital micromirror elements again, after being collected by concentrator by the unnecessary light of digital micro-mirror " OFF state " reflection, through collecting the conduction of light pipe, get back to again in supervisor's light, collecting light pipe is comprised of four parts: with the coupling part of key light pipe, arch section, straight portion and compound parabolic concentrator, satisfied condition while collecting the maximum collection rate of light pipe by calculative determination, it is characterized in that:

Collect four partial common same optical axises of light pipe;

The critical angle of light pipe generation total reflection is

, key light pipe with the angle of collecting light pipe coupling part is

, the radian of arch section is

, the maximum collection angle of compound parabolic concentrator is

, the angle of straight line portion and horizontal plane is

, all angles are all used Rad;

Collect the satisfied condition of light pipe:

;

Collect the radian of light pipe arch section

meet: ;

The satisfied condition of the maximum collection angle of compound parabolic concentrator: ;

The collection surface of compound parabolic concentrator faces by the light of digital micro-mirror " OFF state " reflection;

The quantity of collecting light pipe can be one, also can make a plurality ofly, and concrete quantity is determined by size and the quantity of digital micromirror elements;

The number of branched pipe is determined by quantity and the total light flux of light source;

The effective optical adhesive of plus lens and key light is bonded together.

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