CN1226687A

CN1226687A - Projecting screen with high contrast degree and low loss

Info

Publication number: CN1226687A
Application number: CN 98104765
Authority: CN
Inventors: 姜牧
Original assignee: Individual
Current assignee: Individual
Priority date: 1998-02-16
Filing date: 1998-02-16
Publication date: 1999-08-25

Abstract

A high-contrast low-loss reflecting screen for front projection is disclosed for front-projection TV set, which includes two kinds of front-projection screen. They feature better contrast and low loss even if brighter background light exists. The image quality is similar to that of back projection.

Description

High-contrast, low-loss front projection reflective viewing screen

The invention belongs to optical technical field.

Defectives such as projection TV had been applied to various fields already, and especially rear projection TV has overcome the front projection poor contrast largely, and optical loss is big.But advantages such as the front projection TV is still in light weight, easy for installation with it, save space are in occupation of bigger application share.

Purpose of the present invention just is, overcoming the orthogonal projection reflective viewing screen is subjected to ambient light to influence this weak point, provide two kinds of brand-new orthogonal projection reflective viewing screens, make it can be under stronger ambient light, contrast and brightness that acquisition and back-projection mode are close, thereby reduced requirement greatly, widened its range of application ambient light.

Characteristics of the present invention are: spatially separate projection ray and ambient light, make ambient light can not reflex to the spectators region, thereby under than the bright ring environmental light, contrast also can be better.

Key problem in technology of the present invention is: the cooperation that utilizes local Fresnel lens or local Fresnel reflecting mirror and assorted reverse side mirror, scattering layer etc. is to realize separating of reflection back projected light and surround lighting, owing to be covered with high-reflecting film on the principal reflection interface, thereby intensity loss is less, and brightness is higher.

The invention will be further described with regard to 2 preferred embodiments below in conjunction with accompanying drawing.

(figure one) I type high-contrast, low-loss orthogonal projection reflective viewing screen structural representation.(being called for short I type screen later on).

(figure two) I type screen light path principle synoptic diagram.

(figure three) local fresnel lens structure synoptic diagram.

(figure four) the reverse side mirror structural representation of mixing.

(figure five) II type high-contrast, low-loss front projection reflective viewing screen structural representation.(hereinafter to be referred as II type screen).

(figure six) local Fresnel reflecting mirror structural representation.

(figure seven) atomic optical effect synoptic diagram of scattering of indication in this paper screen member.

Shown in (figure one): by frame 3. I type screen is, the local Fresnel lens 1., assorted reverse side mirror 2., 4. the scattering particulate in the medium is formed, projector sent only by oblique below or oblique upper directive screen.

Shown in (figure two): the optical principle of I type screen is: 7. projected light projects the local Fresnel lens and 1. goes up, after the convex-concave structure scattering 5. of its outside surface, again through the 4. diffusion of scattering particulate of its medium inside, after inside surface 6. go up, after the raised face (RF) refraction of the similar striated of Fresnel lens,, wear the local Fresnel lens 1. together again again by assorted reverse side mirror 2. after the primary reflection surface diffusion, project the spectators zone, promptly obtain the space distribution of rational light intensity.

And 8. most ambient lights pass through the refraction and the reflection of screen, project in the zone that spectators can't see to have gone, very little to the contrast influence.

Shown in (figure three): 9. the surface of local Fresnel lens 6. (figure one) is processed with a series of striped families that are made up of projection, this striped family can be a part of (a local who promptly regards common Fresnel lens as) of the 10. lip-deep circular projection striped of common Fresnel lens family, also can be a part of of other conic section striped family.

For can better diffused ray, the outside surface of local Fresnel lens 5. (figure two) also can be processed some convex-concave shapes, and 4. portion mixes a little scattering particulates within it.

Shown in (figure four): the surperficial of assorted reverse side is processed with some convex-concave shapes and is covered with high reflection film as primary reflection surface, can be metal film, and shown in the figure is the striated projection

The also projection and the depression of some mound shapes.The convex-concave shape also can be processed on another surface, and some scattering particulates can be mixed in medium inside.

Shown in (figure five): II type screen is by the local Fresnel reflecting mirror

And scattering layer constitutes zero, scattering layer

Surface working have convex-concave shape inside be doped with the scattering particulate can with the local Fresnel reflection

Integrated, the local Fresnel reflecting mirror Primary reflection surface On be covered with high reflection film, can be metal film.

Shown in (figure six): the local Fresnel reflecting mirror

Surface working by a series of striped families that form by projection

This striped family can be 10. a part of (figure three) (a local (figure three) who promptly regards common Fresnel lens as) of (figure three) lip-deep circular projection striped family of common Fresnel lens, also can be a part (figure three) of other conic section family.

For can better diffused ray, the outside surface of local Fresnel lens is (figure two) 5., also can be processed with some convex-concave shapes, and portion is mixed with the scattering particulate within it.Shown in (figure seven): scattering particulate as referred to herein Be some optical characteristics and the surrounding medium fine particle of difference to some extent, it is mixed in this paper screen member, but diffused ray.

In a word, the most basic feature of I type screen and I type screen is, local Fresnel lens and local Fresnel reflecting mirror have played topmost effect, they all are with the projected light from projector, reflect and reflect the back and import dead ahead (promptly vertical substantially) with screen, under such prerequisite, after some convex-concave structure are gone up in other interface processing of screen, projection luminous energy is scattered in the solid angle that needs, scattering particulate mixing in screen dielectric layer, also play certain effect, also can overcome some harmful effects simultaneously; The high reflectance coating of primary reflection surface, its total reflectivity can reach at utmost the efficient of light easily to more than 90%.

(generally speaking) local Fresnel lens, the striated projection on the plane of refraction (inside surface) is identical with the projection cross sectional shape of common Fresnel lens, can regard the regional area of Fresnel lens as.

The local Fresnel reflecting mirror is also intended mutually with the striped shape for lugs of Fresnel lens, and be covered with high refractive index layer on protrusion surface.

The local Fresnel of I type structure is saturating, and the surperficial inside surface of (Fresnel) striped family is (figure two) 6., also can (be about to this lens upset use) outwardly.

The local Fresnel lens, and (Fresnel) striped of local Fresnel reflecting mirror, the inclination angle of raised face (RF) is except that each root striped all to some extent the difference, the diverse location of same striped is difference to some extent also, so that the principal direction of scattered light all consistent everywhere at screen.

Claims

1. I type high-contrast, low-loss orthogonal projection reflective viewing screen, its feature just is that this screen is to be combined by local Fresnel lens and assorted reverse side mirror.

2. as screen as described in the claim I, its feature just is that the lip-deep projection striped of local Fresnel lens family is the regional area of the lip-deep projection striped of common Fresnel lens family or the regional area of conic section striped family.

3. as screen as described in the claim I, its feature just is that assorted reverse side mirror is by a series of strips, the raised or sunken composition of mound shape, and the surface is covered with high light reflectivity layer.

4. II type high-contrast, low-loss orthogonal projection reflective viewing screen, its feature just is that this screen is to be combined by local Fresnel reflecting mirror and scattering layer.

5. as screen as described in the claim II, its feature just is, the even lip-deep projection striped of local Fresnel reflection family is the regional area of the projection striped family on the common Fresnel surface, or circular cone is by the regional area of lines line family, and the surface is covered with high light reflectivity layer.

6. as screen as described in the claim II, its feature just is that scattering layer is the strip of being processed by on the curtain plate outside surface, and the projection of mound shape is formed to mix in the plate medium with depression the scattering particulate.