CN85101770A - Back projection screens - Google Patents
Back projection screens Download PDFInfo
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- CN85101770A CN85101770A CN85101770.3A CN85101770A CN85101770A CN 85101770 A CN85101770 A CN 85101770A CN 85101770 A CN85101770 A CN 85101770A CN 85101770 A CN85101770 A CN 85101770A
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Abstract
Proposed a kind of rear projection screen, the lens display on the preceding long face of this screen can spread out with uniform brightness the light from projection light source with the level angle that is actually 180 degree.The ratio that characteristics are and mirror is wide of each lens cells of this lens display is not less than that the ratio of width and top width is not less than 2: 1 between 1: 1 mirror.Another feature of lens displays is that about 2/3rds part of front surface can cover up by black cloth.
Description
Back projection screens is made up of following apparatus: the light disperser on the described screen front surface, and it can receive the light that emits from eikongen and will penetrate each the bar light deflection that comes image is shown with brightness quite uniformly in very wide angular field of view; Described smooth disperser is by one group of compact arranged, normally general parallel convex lens composition; At least some such convex lens are made up of base part, first lateral parts, second lateral parts and the top ends branch relative with first lateral parts.
Back projection screens can be used in various types of equipment, resemble to producing Projection radar display, flight simulator, avionic display, traffic control light, microfilm reader, electronic game machine, projection video monitor and the film rear projection display of the shown usefulness of user.In these were used, the eikongen that is positioned at the screen back was launched light so that form an image on screen plane along axis of projection to screen, and spectators watch in screen the place ahead.
Under the more situation of attendance, spectators scatter along horizontal direction often, at this moment just require a very wide horizontal view angle.Special in the occasion of back projection TV, it is in the very wide horizontal view angle scope that spectators usually are sitting in respect to screen.
The problem that back-projection system runs into is local more eager to excel in whatever one does than other along the direction light of axis of projection, and near more apart from axis of projection like this, it is bright more that video just seems.Back of the body screen color TV projector is general to use three negative electrodes to penetrate orthicon, and promptly red, green and blue look is penetrated orthicon, and their projection lens by separately are to screen prjection.Typical negative electrode penetrate orthicon horizontally in, green penetrate orthicon often be placed in the middle of on the axis of projection, red and blue look is penetrated orthicon and is placed on its optic axis and becomes 5 to spend to 10 positions of spending with the optic axis that green is penetrated orthicon.If without the correction of screen, such arrangement can produce the phenomenon of so-called toner skew.If promptly for the spectators in the middle of being sitting in, redness, green and the very normal words of Lan Sedou, so, concerning whole spectators' surface level, the ratio regular meeting of various toners varies by angle of view.Like this, the image seen of spectators depends on the horizontal level with respect to screen.
In addition, if use rear projection screen existing under the situation of bias light, the contrast of projection image can be subjected to the influence of screen the place ahead bias light reflection.So, should reduce the reflection of bias light at screen front.Once used various masking techniques, between lens, inserted black no reflection events face, to reduce reflection to greatest extent.
For increasing the horizontal view angle scope, various rear projection screens had been proposed once.The rear projection screen that wherein has a kind of William Mu Aiermo (WilliamRElmer) once to obtain United States Patent (USP) 3578841 is a kind of like this screen: its rear surface resembles not Leix Nai Er (Fresnel) eyeglass, can will become parallel rays from the light that eikongen sends, its front surface can be astigmatic in specific horizontal view angle by vertically helping the shape eyeglass to be formed.The shape of vertically helping of eyeglass determined by an equation, and this equation with desired be that the astigmatic angle of benchmark is relevant with the center line.But, when astigmatic visual angle surpasses 60 degree, promptly to count two limits and surpass 30 when spending from center line, the shape of helping of being calculated by this equation does not just have anything to act on.At this moment these must be helped the shape of shape eyeglass change more light some, the visual angle can be expanded to 90 degree like this, i.e. each 45 degree from the center line both sides.
Yoshito Miyatka and Yoshitomi Nagaoka speak of the rear projection screen of other type in the article of " the super wide-angle rear projection screen of one chip " by name that Japanese exhibition 83-587 publishes.The screen system that a kind of being called " fly this III (Phase-III) " is wherein arranged, used trapezoid lens rather than traditional garden column type lens, its end face cross section is identical with traditional garden column type lens and the side is straight and tilt slightly to the center of screen.Say in the article that the horizontal view angle of this system is ± 60 degree, is easy to generate the toner skew during still as the back projection TV screen.Another kind is called the system of " flying this IV (Phase IV) ", also replaces the garden column type lens of standard with trapezoid lens, and the surface of these lens forms two garden cylinders.Between these two garden cylinders, insert the garden column type lens of standard again.Article thinks that this formation can keep bigger horizontal view angle and reduce the toner skew of " flying this IV ".Yet the lens of " flying this IV " contract extremely shortly on xsect, and width is than highly also big, and the width at top is only a little bit smaller slightly than the integral width of lens, and this has just limited the use of black masking technique.
The present invention improves to some extent to the rear projection screen curtain structure, can avoid these shortcomings.Neoteric projection screen has following characteristics: first lateral parts is that about 43 degree are between 85 degree with respect to the average pitch of base part; Second lateral parts also is approximately 43 degree between 85 degree with respect to the average pitch of base part; The first side average pitch and the second side average pitch determine according to following principle: first lateral parts and second lateral parts have the height internal reflection, the ratio of the height of eyeglass and the width of base part was greater than 1: 1, the ratio of the width of base part and top width was greater than 2: 1, the top joins with first lateral parts and second lateral parts, top section partly is made up of two protruding garden post parts and a central fovea garden post, and the top has very strong refractivity.
To top tip part, the effect of top tip part mainly is a refracted ray with the light direct projection of projection thing in the side of the lens combination of our new rear projection screen system that proposes, reflex in the spectators visual field light seldom.Top tip part is made up of two garden cylindricality convex lens and a central fovea garden cylindrical lens, has extraordinary horizontal optical scattering.In addition, when the projection thing has multi-color, for example be used in the back projection vitascan, have the horizontal cathode of three separation to penetrate orthicon, the color offset minimum of lens combination of the present invention.And the whole height of lens can be deceived 60% of rear projection screen area to the ratio of width and top tip part width to the ratio of integral width and is covered up.
To contrast diagram below and introduce the present invention in detail:
Figure one has shown the situation that rear projection screen uses among the present invention in the color TV projection.
Figure two be the employed lens combination of rear projection screen among the present invention amplification the horizontal view of part.
Figure three is horizontal views of this part of 3-3 among the figure two.
Figure four is enlarged drawings of the pinnacle part of lens among the figure three.
Figure five resembles figure three very much, has described to be emitted to through lenses from the light of projection thing the situation of auditorium.
The also similar figure three of figure six has shown that the incident bias light is incident upon the situation on the screen lens.
For ease of understanding neoteric rear projection screen, paper uses placement and the operation of the optical projection system of this projection screen, the various lens surface shapes of using in the subsequent introduction screen and the method that derives these shapes.
10 is back projection vitascans among the figure one, the 12nd, and the rear projection screen that uses in this system. In this placement situation, television reception circuit 14 receives TV video source signal, respectively by independently redness, green and blue look projection cathode are penetrated the back side 22 that orthicon becomes 16,18 and 20 projection screens 12. It is horizontal positioned with respect to axis of projection 23 that these three cathodes are penetrated orthicon (CRT) 16,18 and 20, and green is penetrated orthicon 18 in the centre. In such horizontal positioned situation, CRT16,18 and 20 optical axial are respectively 24,26 and 28, and shape has a certain degree each other. A kind of very typical way is that ruddiness axle 24 and blue streak axle 28 are with respect to the angles of 26 one-tenth 5 to 10 degree of green glow axle. The back side 22 of rear projection screen 12 is planes, the eyeglass of light beam being delivered into collimated light beam that resembles the Leix Nai Er eyeglass not is housed usually, like this, according to the principle of the not Leix Nai Er eyeglass of knowing, can will become parallel rays from projector 16,18 and 20 divergent rays that emit. The front long face 30 of screen 12 also is a plane generally, and a lot of compact arranged perpendicular mirrors unit 32 is housed. Among the present invention lens 32 have certain shape with light refraction in the auditorium 33 among quite wide horizontal view angle α.
In the past, the figure viewed from behind screen system resembling among the figure one useful two or screen be useful single piece type screen also, and this depends on the characteristic of screen. For example, the characteristics of two-piece type screen are that the horizontal view angle is very wide, but the decrease resolution of projection image and phantom is arranged. In addition, under so wide horizontal view angle, in order to reduce to greatest extent color offset, in manufacture process, the control of the registration of screen and screen thickness must be very accurate. The characteristics of single piece type screen are that resolution ratio is higher but the horizontal view angle is littler, generally only have approximately ± 30 about degree. The perpendicular mirrors chip architecture all can be used in single piece type and two-chip type screen among the present invention, and light-dispersing effect is good in the angular field of view of ± 85 degree, and brightness is even, and color offset is little.
Can see among the figure two many parallel vertical lens 32 are arranged in the front surface 30 of projection screen 12.Be lenticular spacing W from the center to the distance at contiguous center in figure three lens combination 32.The lenticular spacing of projection screen 12 of the present invention can be adjusted under various use occasions and the performance of screen is constant, because each assembly of lens combination 32 is to adjust in proportion simultaneously.In fact, lenticular spacing is to decide according to the size of screen and the lens number that requires.During for example as the back projection TV screen, screen size is in 26 English inch to 72 English inch (catercorner length) scopes, and lenticular spacing is roughly from 0.3 millimeter to 1.0 millimeters.Lens combination 32 is done very thin very closely, and what spectators saw is sequential image, and is the same at normalized distance is rendered as binding when watching image just as horizontal linear in the television screen.
Element adjacent in the lens element group 32 preferably is close to, and like this, interelement distance is zero and lenticular spacing equals the width of each element just.Yet in fact interelement has a transition interval, and this can have a lot of ways to handle, such as add a width of cloth bar at interelement.If add such transition interval, its width had better not surpass one of percentage of element width.
Each lens element 32 has a side 34,36 and a pinnacle face 38. Side 34 and 36 can be linear, approximately linear, or cambered outwards.Preferably cambered outwards. Side 34 and 36 average pitch are represented (seeing figure three) with θ and θ respectively.The scope of θ and θ ' greatly about 43 spend to 85 the degree between, decide by desired internal reflection performance.When not necessarily requiring to equate as θ and θ ', θ among the present invention and θ ' preferably are greater than 70 degree.The side has such angle can guarantee that the light of scioptics unit 32 is mapped on the side 34,36 with the angle greater than the critical angle of being derived by Si Naier (Snell) theorem, and light can be decided total internal reflection by these rib shape lens cells like this.θ and θ ' preferably equate, 32 rib-like structure is the side direction symmetry preferably.If θ and θ ' are unequal, and the auditorium is symmetrical, the lens cells on the screen display face 30 will be mutual mirror image.
See too clearly from figure four, the garden arc 40,42 and 44 that end face 38 is equated by three and half warps is formed.As shown in FIG., garden cambered surface 40 and 44 is protruding garden cylinders and garden cambered surface 42 is recessed garden cylinders.But end face 38 refrangibles are reflection ray again, preferably can make light suede to be refracted in the spectators visual field fully go.
The special energy of the refractive index of the average pitch θ of the width W of end face 38 ' depend on side 34 and 36 and θ ', material and eyeglass.The objective of the invention is to propose a kind of lens group structure, it is even that it can provide the visual angle and the image brightness that are actually 180 degree, and color offset is little.For reaching this purpose, the wide W of lens and ratio, the top width W ' of lens height h should get certain numerical value with the ratio of the wide W of mirror.The high h of mirror was greater than 1: 1 the ratio of the wide W of mirror, preferably was not less than 3: 2, the wide W of mirror to the ratio of top width W greater than 2: 1, better greater than 3: 1.
Utilize some design features like this and consider other characteristics of lens arrangement, can design a certain specific purpose is best rear projection screen.If only consider above-mentioned structured data, in the angular field of view of ± 85 degree, the effect screen of design is also splendid.Screen of the present invention can in all sorts of ways and make, as pressure moulding, injection moulding, extruding, casting and photopolymerization.This screen can be made of transparent solid material such as unorganic glass and various plastics.Also can make, preferably use organic glass of composite material.
The single piece type screen is made of two stronger sheets of stickiness.The advantage of single piece type screen is that cost is low, simple.Its thickness is not very serious, does not require the image registration of pros and cons yet.
The vertical astigmatism of screen 12 is smaller comparatively speaking.Therefore, screen 12 has some diffusive.For example, diffusion can be caused by macroscopical refractivity of screen material, can cause that the diffusing layer that forms when can be by each layer bonding causes by the superficial makings at the back side (or in the two-chip type screen any one the surperficial texture except the front), or be produced by their resultant effect.In general, this diffusion has Gaussian distribution, and in the vertical astigmatism of light intensity decreasing less than 50% o'clock nearly ± 10 degree, i.e. diffusion meeting produces one and is about ± the 10 vertical half angle of view of spending.
Be noted that the aligning method of the lens set 32 on the front surface 30 of rear projection screen 12, can produce very wide level astigmatism angle.Can such as 90 degree, just can produce a very wide astigmatic angle in vertical direction at an easy rate with suitable angle of rear projection screen 12 rotations.If requiring to reach in the horizontal direction all has very bright angle on the vertical direction, can increase vertical rib-like structure again on the horizontal rib-like structure in the present invention.
Figure five has illustrated that light is by the scattering situation during lens element 32 among the present invention.From the next light beam Y of projection source
1, Y
2And Y
3The eyeglass that is resembled the Leix Nai Er eyeglass not becomes directional light.Light beam Y
1, Y
2And Y
3Uniform dielectric cathetus in lens source 32 advances.When they ran into side 34,36, because 34,36 internal reflection structure, light beam was reflected, and incident angle equates with reflection angle.When arriving end face 38 at last, its incident angle is less than the critical angle of the interface of eyeglass and air, and light beam is pressed the refraction of Si Naier theorem.
Mention above, lens cells is joined on 32 sides one by one.Another of the side 34 of each mirror unit and adjacent mirror unit forms an outwardly open V font ditch between side 36.The width W that requires mirror unit among the present invention is not less than 3: 1 with the ratio of top width W ', so 2/3rds areas of whole front surface can be deceived and covered up.The black reflection characteristic that should not destroy side 34 and 36 of covering on the screen 12.The best way is to insert a black position 48 that can absorb visible light in 16 li most spaces of ditch, and with the epidermis 50 that connects side it is covered.
Cover even without black, the structure of lens tuple makes the bias light that reflexes in the auditorium lack than traditional single piece type screen.This is that the bias light that arrives ditch portion is in the side 34 of rib- shaped structure 32 and 36 roughly path because the area of ditch 46 has accounted for 2/3rds of whole screen 30 areas greatly.Among the figure, solid line is represented incident light and reflected light, and dotted line is represented refract light.If screen is to make with the material of neutral color, incident light can be decayed gradually.From the back side 12 reflection and get back to through front 30 that the distance than the light process of coming from projection source is twice the range averaging of the light process screen that gets on the auditorium, therefore, the contrast of image is good.
Can make front surface 30 not reflective to increase diffusion front surface textureization.As requested, whole front surface 30 can veining, if screen has black covering, also can make screen not reflective only with end face 38 veinings.To covering screen, even end face 38 usefulness the no reflection events coating that expose can be covered to eliminate reflection, further to improve visual contrast.
Provide the structure that an example illustrates lens cells among the good the present invention of in back projection vitascan behaviour in service below.This example only is in order to say problem to such an extent that more know, the present invention not to be confined in the described example.Coordinate system was designated as 0 as shown in Figure 3 originally, and X-axis represents from the lower left corner to right-hand distance, and Y-axis is represented the distance that makes progress from the lower left corner.The width of lens cells is 0.55 millimeter, is symmetrical for the X=0.275 millimeter.All more than or equal to zero, mirror unit is the continuous function of the slope of Y and Y to the Y value.
The side of symmetry is made of 397 straight-line segments, is defined by following formula:
Slope=M
n=TAN (90 °-0.5 * ARCTAN ((0.2888-X
n) ÷ (0.9280-Y
n)))
Wherein
X
1＝0，Y
1＝0
D＝0.2131÷397＝5.371×10
-4
M
1＝6.5786
X
n＝（n-1）×D
Y
n＝Y
n-1+D×M
n-1
The end points of the 397th line segment is X
398=0.21310, Y
398=0.88348, the shape of side is determined by following interpolation formula: given X, X＜0.21310 and X
i≤ X≤X
I+1Y=Y then
i+ (X-X
i) * M
i+ D
The shape of pinnacle part is following to be determined:
To 0.21310≤X＜0.25735,
Y＝-R
2-（X-X
01）
2+Y
01
X wherein
01=0.23971, Y
01=0.86896, the R=0.03076 millimeter,
To 0.25735≤X＜0.2750(center section),
Y＝+R
2-（X-X
02）
2+Y
02
X wherein
02=0.22750, Y
02=0.91936, the R=0.03076 millimeter
Above formula provided that mirror wide is a side of 0.55 millimeter symmetric lens unit among the present invention.Just as has been noted, all do same change as all mirror units, the wide change of mirror does not influence the performance of mirror unit.When these mirror units were formed the lens screen curtain, adjacent mirror unit preferably connect, if middle spaced words had better not surpass one of percentage of the wide W of mirror.So the mirror tuple of forming is with traditional method polishing.Through check, the gain of She Ji lens is greater than 2.5 like this, and efficient is 79%.In the extremal intensity direction vertical direction 9.5 is spent fully big situation of given half intensity when diffusion, just can reach above gain and efficient.Stronger or increase some horizontal lens combination as diffusion, can obtain bigger vertical seeing image, but this to lose screen gain with amount.
The most handy precision equipment processing of lens combination is as diamond rotation lathe and jewelling tool.The condition of processing is a considerable factor, can allow trickle deviation, the overall formation of lens combination, and promptly the wide wide ratio to top width of ratio, mirror to height of mirror, and side internal reflection and end face refractivity are the Fundamentals of decision screen performance.
More than describe details more of the present invention in detail, wish that the master-hand of one's own profession proposes suggestion for revision.In addition, the present invention is only limited to the scope of declaring in the appendix.
Claims (13)
1, back projection screens has had the astigmatic performance of screen front surface, and it can receive from the light of video source ejaculation and with it and show the compact arranged lens that these astigmatic means comprise series of parallel with brightness quite uniformly in very wide visual angle; One of them part lens is by substrate, and first side, second side reach the top relative with substrate and form; Be characterized in that first side is that about 43 degree are between 85 degree for the mean inclination of base part; Second side is spent between 85 degree about 43 greatly the mean inclination of base part, the definite of the mean inclination of first side and the second side mean inclination should make first side and second side have very strong internal reflection, the ratio of eyeglass height and base part was greater than 1: 1, the ratio of the width of the width of base part and spire part was greater than 2: 1, the spire part is joined with first side and second lateral parts, the spire part partly is made up of the garden post of two protruding garden post parts and a central fovea, and spire partly has the height refractivity.
2, one of feature of the shadow of the figure viewed from behind described in the claim 1 screen is that all compact arranged parallel lens have same structure.
3, the feature of rear projection screen described in the claim 2 is that described first side mean inclination and described two side faces mean inclination are all spent greater than 70.
4, the feature of rear projection screen described in the claim 3 is that described first mean inclination and second mean inclination equate.
5, the feature of rear projection screen described in the claim 1 is that two the protruding garden posts parts of described spire part and the radius of described central fovea garden post part equate.
6, the feature of rear projection screen described in the claim 5 is that described lens are axisymmetric about central authorities.
7, the feature of rear projection screen described in the claim 1 is described height to the ratio of width greater than 3: 2
8, the feature of rear projection screen described in the claim 7 is described width to the ratio of width greater than 3: 1.
9, the lens of rear projection screen described in the claim 6 have first side, second side and spire part, and the width of lens is 0.55 millimeter, is symmetrical for the X=0.275 millimeter, and each symmetrical side is made up of 397 straight-line segments, are determined by following formula:
(90 °-0.5 * ARCTAN((0.28888-X of slope=Mn=TAN
n) ÷ (0.9280-y
n)))
X wherein
1=0, Y
1=0,
D＝0.2131÷397＝5.371×10
-4
M
1＝6.5786
X
n＝（n-1）×D
Y
n＝Y
n+1+D×M
n-1
The end points of the 397th line segment is X
398=0.21310, Y
398=0.88438; The shape of first side is by peaceful interpolation formula is definite down: given X, X＜0.21310 and X
i≤ X≤X
I+1, Y=Y then
i+ (X-X
i) * M
i+ D;
The shape of described spire part is determined by following formula:
To 0.21310≤X＜0.25735, be a garden arc:
Y＝-R
2-（X-X
01）
2+Y
01
X wherein
01=0.23971, Y
01=0.86896, the R=0.3076 millimeter,
To 0.25735≤X＜0.2750(center section), also be the garden arc
Y＝+R
2-（X-X
02）+Y
02
X wherein
02=0.22750, Y
02=0.91936, the R=0.3076 millimeter;
Here, all more than or equal to zero, rib-like structure is the continuous function of the slope of Y and Y to all value of Y.
10, the feature of rear projection screen described in the claim 1 be between the described parallel lens ditch and wherein the extinction solid particle can absorb visible light, system can weaken the visible background reflection of light.
11, the feature of rear projection screen is to be filled with particle in ditch described in the statement 10.
12, the feature of rear projection screen is that it also has diffuse properties described in the statement 1.
13, the feature of rear projection screen described in above each power power is that the back side of screen has the collimation performance, can receive the diverging light that sends from image projector and it is become parallel rays to show at described screen.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN85101770.3A CN1004728B (en) | 1985-04-01 | 1985-04-01 | Back projection screen |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN85101770.3A CN1004728B (en) | 1985-04-01 | 1985-04-01 | Back projection screen |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN85101770A true CN85101770A (en) | 1987-03-04 |
| CN1004728B CN1004728B (en) | 1989-07-05 |
Family
ID=4792044
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN85101770.3A Expired CN1004728B (en) | 1985-04-01 | 1985-04-01 | Back projection screen |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN1004728B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1322354C (en) * | 1996-03-28 | 2007-06-20 | 富士通先端科技株式会社 | Display element, display-element lens, and surface panel for display device |
-
1985
- 1985-04-01 CN CN85101770.3A patent/CN1004728B/en not_active Expired
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1322354C (en) * | 1996-03-28 | 2007-06-20 | 富士通先端科技株式会社 | Display element, display-element lens, and surface panel for display device |
Also Published As
| Publication number | Publication date |
|---|---|
| CN1004728B (en) | 1989-07-05 |
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