CN203533428U - Light guide device applicable to digital micromirror element - Google Patents

Abstract

The utility model provides a light guide device applicable to a digital micromirror element. The light guide device comprises three LED light sources, a main light pipe, three branch pipes, a collection light pipe and a convergence lens. The three LED light sources are concentrated on an aluminum sheet which is connected with the branch pipes. The branch pipes converge light into the main light pipe. A light outlet of the main light pipe and the convergence lens are bonded together. The collection light pipe is connected to the side face of the main light pipe. The collection light pipe comprises four parts: a connecting part connected with the main light pipe, an arc-shaped part, a straight part and a composite paraboloid optical condenser. The conditions which are met for realizing the maximal collection efficiency of the collection light pipe are determined through calculation. The light guide device applicable to the digital micromirror element has the advantages that the collection efficiency of the collection light pipe which meets the given conditions is the best, so that the light utilization rate is increased, and heat of a system is reduced; the three LED light sources can be transmitted simultaneously through the three branch pipes; the convergence lens and the main light pipe are bonded together through optical adhesive, so that light loss in the transmission process is reduced.

Description

A kind of light pipe device that is applicable to digital micromirror elements

Technical field

The utility model generally relates to light pipe, and relates in particular to a kind of light pipe device that is applicable to digital micromirror elements.

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, and 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 micro mirror in a large number 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, and 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 utility model provides a kind of light pipe device that is applicable to digital micromirror elements.

The utility model solves the problems referred to above by following proposal:

A kind of light pipe device that is applicable to digital micromirror elements, comprise three LED light sources, key light pipe, three branched pipes, collection light pipe and plus lens, three LED light sources concentrate on an aluminium sheet, aluminium sheet is connected with branch light pipe, branch's light pipe converges to light in key light pipe, light-emitting window and the plus lens of key light pipe are bonded together, collection light pipe is connected to the side of key light pipe, collecting light pipe is comprised of four parts: with coupling part, arch section, straight portion and the compound parabolic concentrator of key light pipe

Satisfied condition while collecting the maximum collection rate of light pipe by calculative determination;

Remove beyond link position, the shape of cross section of whole light pipe is circular;

Whole light pipe adopts resin material, critical angle

, the maximum collection angle of compound parabolic concentrator

, key light pipe and the angle of collecting light pipe coupling part

;

Three LED light sources are focused on to one block above aluminium sheet, and aluminium sheet is positive to link together with three branched pipes, and the aluminium sheet back side connects heat abstractor.

Compare with prior art art, this device beneficial effect has: 1. meet best to the collection light pipe collection rate of condition, improved light utilization efficiency, reduced the heat of system; 2. three branched pipes can meet three LED light sources and transmit simultaneously; 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 three LED light sources.

Fig. 3 is the schematic diagram of compound parabolic concentrator.

Fig. 4 is the schematic diagram that compound parabolic concentrator is collected light.

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

Fig. 6 collects another schematic diagram that light pipe is collected light.

Fig. 7 is the schematic diagram of plus lens.

1. aluminium sheets in figure, 2.LED light source, 3. branched pipe, 4. key light pipe, 5. optical axis, 6. collects light pipe and key light pipe jointing part and divides, 7. collect the arch section of light pipe, the straight portion of 8. collecting light pipe, 9. compound parabolic concentrator, 10. plus lens, 11. micro mirrors, 12. micro mirror initial positions, 13. planes of incidence, 14. exit facets, 15. normals.

The specific embodiment

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

With reference to Fig. 1, in an 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 collector gets up ray-collecting, and light comes back in key light pipe by collecting light pipe, and light completes and recycles.Three LED light sources concentrate on an aluminium sheet, and the light inlet of the front of aluminium sheet and three branched pipes links together.

Fig. 2 is the schematic diagram of LED light source, and three LED light sources are concentrated on to one block above aluminium sheet, connects heat abstractor after aluminium sheet, can save space, and help system heat radiation.

Fig. 3 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.If plane of incidence radius is a, 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. 4, 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, and with the angle of the optical axis of light pipe be also after primary event

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

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

.According to this condition, the maximum collection angle of this device compound parabolic concentrator is 30 °.

Fig. 5 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 figure, at light inlet, the angle in optical axis is incident ray

, light, after the transmission of light pipe, is still 30 ° at the angle of light-emitting window and optical axis.

With reference to Fig. 6, in an 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.Whole light pipe adopts resin material, and the critical angle of total reflection occurs

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

, the maximum collection angle of compound parabolic concentrator is

.

The angle of Ray Of Light and optical axis is

, 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, it enters in key light pipe and wants total reflection can occur so.The incidence angle of light in key light pipe is greater than critical angle

, in triangle ABC,

be greater than

,

, so

maximum be 17.5 °, in this device, collecting the angle that light pipe and key light pipe jointing part divide is 17.5 °.

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 utility model and effect only; and the embodiment of part; for the person of ordinary skill of the art; do not departing under the prerequisite of the utility model creation design; can also make some distortion and improvement, these all belong to protection domain of the present utility model.

Claims (1)

1. a light pipe device that is applicable to digital micromirror elements, comprise three LED light sources, key light pipe, three branched pipes, collect light pipe and plus lens, three LED light sources concentrate on an aluminium sheet, aluminium sheet is connected with branch light pipe, branch's light pipe converges to light in key light pipe, light-emitting window and the plus lens of key light pipe are bonded together, collection light pipe is connected to the side of key light pipe, 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:

Remove beyond link position, the shape of cross section of whole light pipe is circular;

Whole light pipe adopts resin material, critical angle

, the maximum collection angle of compound parabolic concentrator

, key light pipe and the angle of collecting light pipe coupling part

;

Three LED light sources are focused on to one block above aluminium sheet, and aluminium sheet is positive to link together with three branched pipes, and the aluminium sheet back side connects heat abstractor.

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