CN1431540A - Polarized light conversion device possessing optical pipes - Google Patents

Abstract

The polarized light conversion device is composed of the light lamp, the optical pipe, the reflecting plate, the 1/4 wave piece and the reflecting polarizer sheet. The optical pipe possesses the channel formed by the circumambient walls. The light entrance faced to the lamp with the reflecting plate being installed is in the channel and the light exit is apart from the light entrance. The 1/4 wave piece is positioned between the light entrance of the optical pipe and the reflecting polarizer sheet. The opening is set up on the reflecting plate for the light beam from the lamp to going through. When the light goes into the channel of the optical pipe from the opening on the reflecting plate, the S polarized light is reflected so as to pass through the 1/4 wave piece twice, being turned to P polarized light.

Description

Polarized light conversion device with photoconductive tube

(1) technical field

The present invention relates to a kind of polarized light conversion device, particularly relate to and a kind ofly utilize cooperation between reflecting polarized wafer and photoconductive tube to reflect and change the portions of light linear polarization, to improve the polarized light conversion device of light utilization efficiency.

(2) background technology

Only a kind of electromagnetic wave, it also has the direction of polarization except having characteristics such as working direction, frequency, phase place, and the fixing light of electric field direction of vibration and magnetic field direction of vibration is called as polarized light.Line polarisation parallel with direction of an electric field or the vertical incidence face is called as P polarization and S polarization again respectively in it; the above-mentioned polarized light that only occurs in the plane and describe with mathematical equation easily is utilized easily, therefore in general projection display system regular meeting with polarized light conversion equipment general wherein a kind of polarization state light convert the utilization that another kind of polarization state light is beneficial to light to.

Consult Fig. 1,2, projection display system 1 comprised in the past: one produces lamp source 11, a matrix lens integrator 12, a Polarization converter 2, a lens combination 13 and a display board 14 of light, wherein lamp source 11 has the bulb 112 that a reflective lampshade 111 and produces light, the ray cast that lampshade 111 can send bulb 112 is to matrix lens integrator 12, through Polarization converter 2, lens combination 13, project again on the display board 14 then.Polarization converter 2 had a reflection seat 21 and several are between the upper and lower every the 1/2 ripple plate 22 that be arranged in parallel in the past, reflection seat 21 has a plane of incidence 211 parallel to each other, one exit facet 212, with several the first filmings 213 between 212 of the plane of incidence 211 and exit facets, several second plated films 214, wherein the plane of incidence 211 is towards matrix lens integrator 12, which is provided with several lightproof areas 215 of parallel interval setting up and down, and exit facet 212 is towards display board 14, each plated film 213,214 inclinations from top to bottom parallel to each other, each 1/2 ripple plate 22 be spaced and parallel be located at 14 of exit facet 212 and display boards, the position of its setting, the reflection position correspondence of length and the first filming 213.

When projection display system 1 adopts the video picture of S polarization light, the light that contains P polarization and S polarization is to invest matrix lens integrator 12 simultaneously by lamp source 11, enter Polarization converter 2 again, when P polarization light trend of purchasing is not established the plane of incidence 211 of lightproof area 215, can directly penetrate the first filming 213, and, convert the S polarization light then to and invest display board 14 at last through 1/2 ripple plate 22.When the light of S polarization is not established the plane of incidence 211 of lightproof area 215 in trend of purchasing, be to be incident upon the first filming 213, reflex to second plated film 214 then, through 214 reflections of second plated film, invest display board 14 by the position of not corresponding 1/2 ripple plate 22 on the exit facet 212 at last again.When supposing that projection display system 1 adopts the P polarization light, this 1/2 ripple plate 22 is positions of corresponding S polarization light projection, below no longer explanation.

Projection display system 1 was in order to allow the light of investing display board 14 have identical polarization state in the past, it is that several putting approximately is the lightproof area 215 of 1/2nd planes of incidence, 211 areas on the plane of incidence 211 of reflection seat 21, could effectively be changed and be used by the light of the plane of incidence 211 like this, above-mentioned design no doubt can guarantee that the light that projects display board 14 has consistent polarization state, but the light that this design makes lamp source 11 cast out has 50% can't be utilized approximately, therefore though Polarization converter 2 can provide the light of identical polarization state in the past, but its light conversion efficiency is low, and the brightness that can provide is also relatively poor.

(3) summary of the invention

The purpose of this invention is to provide a kind of preferable light conversion efficiency that has, and can improve the polarized light conversion device with photoconductive tube of brightness.

Polarized light conversion device of the present invention is to be used on the projection display system, so that the light source of projection display system video picture to be provided, it is characterized in that: this polarized light conversion device comprises: a lamp source, a photoconductive tube, a reflecting plate, one 1/4 ripple plates and a reflecting polarized wafer; This lamp source can produce light, and the light-ray condensing of generation is by a focus; This photoconductive tube is to be positioned on the travel path of light, and it has a surrounding wall and and defines the passage that forms by this surrounding wall, has a light entrance and the light exit away from this light entrance that is positioned on the focus on the passage.This reflecting plate is the light entrance that is installed in photoconductive tube, and it has a lateral surface towards the lamp source, a medial surface and towards light exit runs through the opening that the medial and lateral face also can supply light to pass through, and this opening is positioned on the focus of light; This reflecting polarized wafer is positioned at the light exit place of photoconductive tube, and it selectively allows wherein a kind of polarization state light pass through, and allows another kind of polarization state light line reflection; This 1/4 ripple plate is to be positioned between reflecting plate and reflecting polarized wafer; The light that produces when the lamp source is when the opening of reflecting plate enters the passage of photoconductive tube, with the form of mixed light by the light exit warp let-off 1/4 ripple plate, wherein a kind of light of polarization state is understood the penetrating reflective polaroid, the light of another kind of polarization state is reflected and is subjected to the reflection of reflecting plate once again behind 1/4 ripple plate, and this strand light is penetrating reflective polaroid by 1/4 ripple plate and after changing polarization state once more.

For further specifying above-mentioned purpose of the present invention, design feature and effect, the present invention is described in detail below with reference to accompanying drawing.

(4) description of drawings

Fig. 1 is the synoptic diagram of a projection display system, and the corresponding relation between miscellaneous equipment on the Polarization converter and projection display system in the past is described.

Fig. 2 is the part enlarged drawing of the Polarization converter in the past of Fig. 1.

Fig. 3 is the synoptic diagram of first preferred embodiment of polarized light conversion device of the present invention.

Fig. 4 is the synoptic diagram of second preferred embodiment of polarized light conversion device of the present invention.

(5) embodiment

As shown in Figure 3, the polarized light conversion device of present embodiment can provide equidirectional polarization light for utilization, and described polarized light conversion device comprises: a lamp source 3, a photoconductive tube 4, a reflecting plate 5,1 ripple plates 6 and a reflecting polarized wafer 7.This lamp source 3 has the bulb 31 and a lampshade 32 of a generation light source, has an oval reflecting surface 321 on lampshade 32, concentrates projection by a focus 33 with the light that bulb 31 is produced.

But hollow tube that this photoconductive tube 4 is reflection rays or solid column, and be positioned on the path of ray cast, present embodiment explains with hollow tube.This photoconductive tube 4 have one along a center line around surrounding wall 41 and define the passage 42 that forms by this surrounding wall 41, on surrounding wall 41, have a reflection anchor ring 411 towards passage 42, and this passage 42 have a light entrance 421 and the light exit 422 away from this light entrance 421 near lamp source 3.When photoconductive tube 4 was solid column, passage 42 herein was a kind of solid constructions that supply light to pass through.

This reflecting plate 5 is to be installed on the light entrance 421 of photoconductive tube 4, it has the opening 53 that a lateral surface 51 towards lamp source 3, a medial surface 52 and towards light exit 422 run through medial and lateral face 52,51, described opening 53 just in time is positioned on the focus 33 of light, and the ratio of the sectional area of this opening 53 and reflecting plate 5 total sectional areas can adjust according to the conversion efficiency of design.In the present embodiment, the sectional area of opening 53 is 1/3rd of reflecting plate 5 total areas.

This 1/4 ripple plate 6 is installed in light exit 422 outsides of photoconductive tube 4, it is a kind of optical module with birefringence, function is to adjust the phase place of light, when linear polarization light incident 1/4 ripple plate 6, if the angle of polarization direction and 1/4 ripple plate, 6 optical axises is 45 °, the light that passes through will become circular polarization state.On the contrary, when the light incident 1/4 ripple plate 6 of circular polarization state, if when the angle of light that passes through and 1/4 ripple plate, 6 optical axises is 45 °, the light that passes through will become linear polarization light.Use this principle, make linear polarization light incident 1/4 ripple plate 6 and place a mirror surface thereafter, circularly polarized light can obtain and the vertical linearly polarized light in the preceding polarization direction of incident after reflection once more through 1/4 ripple plate 6.The present invention is based on this principle, so must there be 45 ° angle the polarization direction of the optical axis of 1/4 ripple plate 6 and following reflecting polarized wafer 7.

This reflecting polarized wafer 7 is mounted in the place ahead of 1/4 ripple plate 6, and and photoconductive tube 4 be positioned at 1/4 ripple plate, 6 both sides accordingly about being, function is optionally to allow the P polarization light pass through, and the reflection of the light of S polarization.

When the bulb 31 in lamp source 3 produces light, light can be invested the opening 53 of reflecting plate 5 by oval reflecting surface 321 reflections, go forward side by side and mix in the passage 42 of photoconductive tube 4, send by the light exit 422 of photoconductive tube 4 at last, then through 1/4 ripple plate 6 by reflecting polarized wafer 7.At this moment, nearly 50%P polarization light and 50% S polarization light in the light, 90% P polarization light meeting penetrating reflective polaroid 7 is wherein arranged approximately, account for 45% of whole light greatly, and about 50% S polarization light and 5% P polarization light (10% in the P polarization light just) can reflect the passage 42 that enters photoconductive tube 4 through 1/4 ripple plate 6 once again in the light when running into reflecting polarized wafer 7.

When the S polarization light is reflected when entering in the photoconductive tube 4, be subjected to the reflection of reflecting plate 5, having partly, the S polarization light of ratio reflexes to light exit 422 by reflecting plate 5, then for the second time by 1/4 ripple plate 6, when the S polarization light passes through 1/4 ripple plate 6 for the second time, originally the S polarization light will change the polarization axle angle, and change the P polarization into by initial S optical rotation, the penetrable reflecting polarized wafer 7 of 90% P polarization light then, just the S polarization state light of script 50% is when reflection is passed through photoconductive tube 4 for the second time, have part and convert P polarization and penetrating reflective polaroid 7 to, the calculating formula of this light penetration rate is: 0.5 (S polarization light originally) * 2/3 (supposing reflecting plate 5 reflexible area ratios) * 0.9 (the penetrable reflecting polarized wafer 7 of 90%P polarization light)=0.3.

And in the 5%P polarization light that originally is reflected, penetrate out through reflecting polarized wafer 7 through can have an appointment 2% P polarization light of secondary reflection, the formula of its calculating is: 0.05 * 2/3 * 2/3 * 0.9=0.02 (2%), therefore the light that is produced by lamp source 3 passes through the reflection and the conversion of present embodiment, its actual P polarization light that passes is: (the S polarized light is through changing over the ratio of P polarized light behind the secondary reflection originally)+0.02,0.45 (P polarized light originally)+0.3 (amount of P polarized light after the secondary conversion is reflected)=0.77, the penetrance of described light apparently higher than in the past 0.5, therefore this design of the present invention can improve light utilization efficiency effectively, and the amplitude that its light utilization efficiency improves is: 0.77/0.5=1.54 doubly.

Can above embodiment formulism is as follows: suppose that the P of incident light conduit 4 and S polarisation intensity respectively are 1 unit, Tp, Ts, Rp, Rs are the penetrance and the reflectivity of P and S polarisation, A, Am are photoconductive tube 4 total sectional areas and reflective surface area, and the polarisation utilization factor of the exit facet of this photoconductive tube 4 is: $\mathrm{Tp}+\frac{2\×\mathrm{Rs}\×\mathrm{Am}\×\mathrm{Tp}}{A}$

Consult Fig. 4, the necessary assembly of second embodiment of the invention is identical with first embodiment, and comprise: lamp source 3, photoconductive tube 4, reflecting plate 5,1/4 ripple plate 6 and reflecting polarized wafer 7, the difference of the present embodiment and first embodiment is: this 1/4 ripple plate 6 is located in the passage 42 of photoconductive tube 4, and and reflecting plate 5 near, change by aforementioned 1/4 ripple plate 6 installation sites can reach identical effect equally.That is to say,, just can reach the effect of expection as long as 1/4 ripple plate 6 of the present invention is positioned at 7 of the light entrance 421 of photoconductive tube 4 and reflecting polarized wafers.

By above explanation as can be known, polarized light conversion device of the present invention had not only seen like product, and this design also can make the utilization factor of light rise to 1.54 times of person in the past or higher, has promoted the brightness of collocation system indirectly.

Certainly, those of ordinary skill in the art will be appreciated that, above embodiment is used for illustrating the present invention, and be not to be used as limitation of the invention, as long as in connotation scope of the present invention, all will drop in the scope of claims of the present invention variation, the modification of the above embodiment.

Claims (4)

1. polarized light conversion device with photoconductive tube, it is characterized in that: this polarized light conversion device comprises:

One can produce the lamp source of light, and the light-ray condensing of generation is by a focus;

One photoconductive tube is positioned on the travel path of light, has a surrounding wall and and defines the passage that forms by this surrounding wall, and this passage has a light entrance and the light exit away from this light entrance that is positioned on the focus;

One reflecting plate is installed in the light entrance of photoconductive tube, has the opening that a lateral surface towards the lamp source, a medial surface and towards light exit run through the medial and lateral face and can pass through for light, and this opening is positioned on the focus of light;

One reflecting polarized wafer is positioned at the light exit place of photoconductive tube, selectively allows wherein a kind of polarization state light pass through, and allows another kind of polarization state light line reflection; And

One 1/4 ripple plates are positioned between reflecting plate and reflecting polarized wafer;

The light that produces when the lamp source is when the opening of reflecting plate enters the passage of photoconductive tube, with the form of mixed light by the light exit warp let-off 1/4 ripple plate, a kind of light penetration reflecting polarized wafer of polarization state wherein, the light of another kind of polarization state is reflected and is subjected to the reflection of reflecting plate once again behind 1/4 ripple plate, this strand light can pass through 1/4 ripple plate once more, and penetrates this reflecting polarized wafer after changing polarization state.

2. have the polarized light conversion device of photoconductive tube according to claim 1, it is characterized in that: the opening section of reflecting plate is long-pending to be 1/3rd of this reflecting plate total sectional area.

3. have the polarized light conversion device of photoconductive tube according to claim 1, it is characterized in that: this 1/4 ripple plate is positioned between the light exit and reflecting polarized wafer of photoconductive tube.

4. have the polarized light conversion device of photoconductive tube according to claim 1, it is characterized in that: this 1/4 ripple plate is the passage that is positioned at photoconductive tube, and abuts reflecting plate.

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